CN101048059B - trimmer head - Google Patents

Abstract

The invention provides a trimmer head. The trimmer head (10) for a flexible line rotary trimmer comprises: a housing (14) adapted to be operatively connected to the trimmer to effect rotation of the head (10); and a spool (16) operatively connected to the housing (14) for rotation therewith. The spool (16) defines at least one inwardly extending line receptor channel (91) preferably formed by a plurality of inwardly tapered walls (93) so as to be polygonal in cross-section. With such a configuration, the channel walls (93) will firmly grip the cutting wire (17) when the cutting wire (17) is inserted into the channel (91) and wound around the spool. For uniform winding of the cutting line (17), a plurality of cams (44), cam abutment and sliding surfaces (46) are operatively connected to the housing (14) and the spool (16) so that, when the spool (16) is manually rotated in a driving direction relative to the housing (14), the spool (16) reciprocates axially in the housing (14) so that the cutting line (17) is uniformly distributed around the body of the spool (16).

Description

trimmer head

technical field

The present invention relates to an improved trimmer head for use in a flexible wire rotary trimming device for trimming lawns, weeds and other vegetation. More specifically, the present invention seeks to improve trimmer heads of the "bump-feed" type, such as disclosed in U.S. Patent No. 4,458,419 and No. 4,959,904, and such Wire loading of the head for easier manual operation. The contents of said patents are hereby incorporated by reference as fully set forth below.

Background technique

Trimmer heads for flexible line rotary trimmers typically carry one or two lengths of flexible nylon cutting line wound on an internal spool with the ends of the line passing through the side walls of the trimmer head facing each other. The hole sticks out. The head is threadedly mounted on one end of an elongated shaft and is rotated at high speed by a gas or electric motor so that the end of the cutting wire extends radially from the trimmer head and cuts through weeds or other plant. When the cutting wire protruding from the trimmer head breaks or becomes excessively worn, the cutting wire must be cut and a new cutting wire pulled from the spool through the outlet eyelet in the side of the housing. The bump feed head includes a wire feed mechanism that responds to a deliberate bump on the ground by the operator to feed a measured length of new cutting wire, usually via a hood extending from a shroud mounted to the trimmer above the cutting head. A blade, spaced a predetermined distance from the perimeter of the trimmer head housing, cuts the new cutting line to the required length. Manual heads do not include any such wire feeding mechanism. The fastening nut holding the housing portion of the trimmer head to the spool must be loosened so that the spool can be detached from the housing and manually rotated relative to the housing to pay out additional cutting wire. The spool and housing are then secured again by fastening means.

In bump-fed heads and manual heads, one or more lengths of cutting wire are usually wound by hand on a spool. Since most cutting heads employ two lengths of wire protruding from opposite sides of the cutting head, care must be taken during the winding of the spool to avoid crossing or otherwise tangling of the two strands in the spool, crossing Or tangles will interfere with the new thread payout. This is especially important in impact feed heads where the head is bumped against the ground to use centrifugal force to pull a new length of line from the spool during use, as any tangle of line will interfere with proper line feeding . Difficulty loading the line properly on the spool is the most common complaint of home users of flexible line trimmers. It is also a time-consuming task for professional users.

Early bump feed mechanisms typically included dog or friction clutches between the spool of wire and the surrounding housing. By impacting the extension of the spool on the ground or other fixed object, the friction clutch is temporarily disengaged for a period of time, the length of which depends on the duration of the impact. The dog clutch is disengaged by the bump and then snapped on at the next opportunity to feed a length of wire relative to the dog clutch's engagement point. Such dog clutches have outwardly extending ribs that engage inwardly extending abutment tangs so that when only a length needs to be transferred, skillful bumping is required. However, friction and excessive bumping in such devices often results in feeding two or more wire segments, particularly when the device has been used and the ribs and corners of the tangs are worn such that a secure engagement is no longer ensured. This unavoidable sudden operation of the dog clutch results in this wear.

A bump feeding mechanism was subsequently developed that automatically feeds a predetermined length of wire with each bump, regardless of the duration of the bump, and does not lose this function in continued use. Such a device is disclosed and is the subject of US Patent No. 4,458,419, which is incorporated herein by reference. As detailed in that patent, an improved trimmer head includes a spool holding one or more cutting coils and a simplified mechanism that selectively allows the spool to move relative to the housing in response to impact of the head with the ground. The body performs relative motion to release a line of measured length. This simplified payout mechanism includes a novel spring-loaded cam and cam follower arrangement, wherein the cam follower includes two pairs of diametrically opposed and generally inwardly facing abutment surfaces that surround the trimmed The axis of rotation of the device housing is aligned. The abutment surfaces are thus spaced apart by 90° and are carried by a depending cylindrical wall circumscribing the inner chamber. The cam member is disposed in the chamber in threaded engagement with the extended lower end of the drive bolt of the trimmer housing and defines two vertically adjacent cams, each cam being of square configuration and defining four vertically disposed A cam surface adapted to engage an abutment surface on the cam follower. The rotation of the upper cam and the lower cam is staggered by 45°.

In operation, the housing is rotationally driven by the drive bolt through the connection between the upper end of the drive bolt and the trimmer drive. The housing and cam member are thus driven by the drive bolt and, due to the engagement between the cam surface on the cam member and the abutment surface on the cam follower, in turn drive the cam follower and the cam follower mounted on the cam follower. spool. The spool carrying the wire is disposed about the cylindrical wall of the cam follower and is coupled to the cam follower by a pair of opposed outwardly projecting studs on the cam follower member, wherein the studs extend to form the wire. in the groove in the shaft interior. The spool is provided with a striker at its lower end, so that when the striker is pressed against the ground or collides with the ground, the housing overcomes the force of the spring and moves downward relative to the spool to disengage the lower cam from the cam follower and allow the cam member to rotate 45° relative to the cam follower so that the cam surface of the upper cam will abut the abutment surface on the cam follower. This produces a similar degree of relative rotation between the spool and the housing. Once the force of the impact is removed, the spring loading forces the spool and housing back to their relative positions, which separates the cam surface on the upper cam from the abutment surface of the cam follower and allows the cam member and cam follower and thereby Rotating the spool and housing relative to each other another 45°, for a total of 90° per impact, provides the predetermined relative relationship between the housing and the spool required to pay out the desired length of line through the hole in the trimmer housing. rotate. Since the cam interacts with a simple, inwardly facing cam follower surface formed on only a single layer, the release mechanism is considered to be relatively economical to manufacture and due to the presence of a Large abutment surface area, so the device is durable, trouble-free and reliable.

Due to early difficulties in molding some of the components of the cutting head disclosed in Patent No. 4,458,419, the head was more expensive to manufacture than expected. The development of new materials subsequently reduced manufacturing costs. At the same time, however, similar bump-fed drive mechanisms were developed in which a plurality of larger square cams were formed on the upper and lower outer diameter surfaces of the spool, and corresponding cams were formed by the upper and lower portions of the housing surrounding the spool. of multiple cam followers. Such heads are disclosed in US Patent No. 4,959,904, incorporated herein by reference, and are still in production.

Over the years, as competition from foreign manufacturers intensified, it became apparent that even with the development of new materials, the manufacture of the early crash feed mechanisms covered by Patent No. 4,459,419 was not as economical as was earlier thought. The crash feed mechanism consists of multiple parts, some of which must be assembled manually. Additionally, vibration, threaded engagement between the cam member and drive bolt, and heat generated by the trimmer require the use of chemical adhesives with high melting points to prevent the cam member and cam follower from loosening from the drive bolt. However, this adhesive has a very high breaking torque, rendering the threaded connection permanent. As a result, some parts of the head cannot be replaced after wear. Therefore, a major modification of this head was made to retain all the advantages of the original head and also utilize fewer parts without any manual assembly and without the use of chemical bonding. This modification is the subject of a pending U.S. patent application entitled "Trimmer head for use in flexible line rotary trimmers," filed on October 2, 2003. Filed on , Serial No. 10/677,700, this application is a continuation-in-part of the aforementioned patent application. The bump-fed and manual head of the present invention retains all the advantages of the aforementioned heads and adds to the aforementioned heads the ability to more quickly and easily wind a length of cut wire uniformly on a spool without substantially increasing the Cost of production.

Contents of the invention

Briefly, the present invention comprises an improved impingement-fed rotary trimmer head comprising: a housing defining a depending axially disposed tubular extension adapted to For receiving a drive bolt therein, and the tubular extension is shaped to define a first interference fit with the drive bolt and a second interference fit with the cam member, such that rotation of the drive bolt causes the housing and The cam member rotates accordingly. The cam member defines a pair of vertically adjoining cams, the cams are preferably square in cross-section, and each cam defines four vertically disposed cam surfaces, the upper one of the cams being opposite to the lower one of the two cams. One rotation is staggered by 45°. A generally cylindrical cam follower defines two pairs of diametrically opposed and inwardly facing abutment members aligned about a central axis of the housing passage, the cam follower being disposed on the near the cam member described above. The abutment members are spaced 90° apart in a common horizontal plane and are carried by a cylindrical wall of the cam follower extending around the cam follower. Each of the abutment members defines an angularly disposed leading surface and a trailing surface, the trailing surface defining a cam abutment surface. A coil spring presses the cam follower downwardly against the cam member, and a slidably disposed fastener engages the extended lower end of the drive bolt adjacent the lower end of the cam member such that the cam member is vertically movable relative to the cam follower against the force of the coil spring between a first drive position in which the front cam surface on the lower cam is aligned with the the rear cam abutment surface on the cam follower is in planar alignment with the front cam surface on the upper cam in planar alignment with the rear cam abutment surface on the cam follower in the second drive position alignment.

In operation, the drive motor on the trimmer rotates the trimmer housing and the cam member in a first direction as the cam surface on the lower cam engages the rear cam on the cam follower The abutment surfaces abut, causing rotation to be imparted to the cam follower. As engagement lugs on the cam follower project into slots in the inner wall of the spool, a corresponding rotation of the spool is caused. When the cutting head hits the ground, the cam rotates 45° relative to the cam follower, and when the head lifts off the ground, a further 45° rotation occurs, causing a gap between the spool and the housing. Rotate 90° relative to each other, so that a new cutting line of predetermined length is released every time the head collides with the ground, regardless of the duration of the collision.

To facilitate loading of cutting wire on the head, said spool is provided with a wire receiver channel, preferably tapered and polygonal in cross-section, which extends substantially radially into the spool upper flange, and adapted to radially align the outlet eyelet in the housing wall by rotating the spool relative to the housing. When the end of a length of cut wire is inserted through each eyelet and the wire is pushed firmly into the aligned receiver channel, the wire will pass securely through the channel wall as it is pushed back toward the spool at an acute angle. stay in place. Therefore, by keeping the housing stationary and rotating the spool in the same direction as the spool in drive mode, it is possible to wind a fixed length of wire around the rotating spool, thereby eliminating the need to move the spool to load the wire. The spool is detached from the housing.

In order to distribute the length of cutting wire evenly around the spool and to prevent tangling in the spool, the rear surface of the lower cam abuts and is perpendicular to the cam surface above it and the rear surface of the cam follower The front surfaces on the abutment members are relatively sloped such that rotating the spool in the drive direction while holding the housing stationary will cause the sloped front surfaces on the abutment members on the cam follower to periodically abut against Take the rear surface on the lower cam, slide along and up on the lower cam rear surface, thereby compressing the coil spring. Once the cam surface clears the cam abutment member, the coil spring will force the cam follower downward, thereby realigning the cam abutment surface and the lower cam. As a result, continued manual rotation of the spool relative to the housing will cause the wire to be wound around the spool and provide vertical reciprocation or clutching of the spool relative to the housing while the wire is wound on the spool, such that The wire is evenly arranged around the spool. Preferably, printed markings are molded into the upper surface of the spool to allow the user to easily orient the spool relative to the housing with the receiver channel radially aligned with the spool in the housing. A wire exit hole to enable easy insertion of wire through the eye loop into the receiver channel for loading wire around the spool.

The wire receiver channel and spool clutch mechanism of the present invention to facilitate wire loading can also be used with other bump feed head configurations and manual heads as well. In each case, the wire receiver is provided on a spool flange which can be radially aligned with the outlet eyelet in the housing. In an impact feed head as disclosed in U.S. Patent No. 4,959,904, at least the rear surface on the lower cam follower, defined by the lower radially outer surface of the spool, is beveled so that when the housing is in a fixed position Simultaneously, rotation of the spool in the drive direction will cause the spool to periodically ratchet up and down in the housing as the cutting wire is pulled inwardly through the eye ring and wound around the spool, thereby making the length The wire is evenly distributed around the spool in the housing. The front radial surface of the lower cam follower and the rear surface of the cam formed by the upper and lower portions of the housing may also be sloped to provide a smoother clutching movement to the head during winding of the wire onto the spool.

In a manual feed head such as that disclosed in U.S. Patent No. 4,145,809, a plurality of pins or drive projections are disposed around and protrude upwardly from the upper surface of the spool and into dimensions of the upper surface of the housing holes corresponding to the spacing so that rotation of the housing will cause a corresponding rotation of the spool. By providing a radially alignable wire receiver in the spool flange and sloping the inner upper surface of the housing between the holes therein, the wire end can be inserted through the eye ring into the receiver channel and retained by the spool , so that rotation of the bobbin relative to the housing as described above will cause the protrusion on the bobbin to repeatedly move down adjacent ramps and snap up into the next hole. Continued relative rotation will thus cause the required reciprocation of the spool in the housing to distribute the cutting wire evenly around the spool.

Description of drawings

Figure 1 is a perspective view of a first embodiment of the trimmer head of the present invention showing the drive bolt securing the trimmer head to the rotary trimmer.

FIG. 2 is an exploded perspective view of the various components making up the embodiment of the trimmer head of the present invention shown in FIG. 1 .

Fig. 3 is a cross-sectional view of the trimmer head housing of the present invention taken along line 3-3 in Fig. 2 .

Figure 4A is a top view of the cam member of the present invention.

Figure 4B is a side view of the cam member of the present invention.

Figure 5A is a top view of a cam follower member of the present invention.

Figure 5B is a side view of a cam follower member of the present invention.

FIG. 5C is a cross-sectional view taken along line 5C-5C in FIG. 5A.

Figure 6 is a top view showing the relative positioning of the cam member and cam follower in their normal operating positions.

FIG. 6A is a cross-sectional view taken along line 6A-6A in FIG. 6 .

Fig. 7 is a top view showing the relative positioning of the cam member and cam follower in the wire feeding position.

Figure 8 is a top view showing the relative positioning of the cam member and cam follower in the wire winding position.

FIG. 8A is a cross-sectional view taken along line 8A-8A in FIG. 8 .

8B is a cross-sectional view showing the movement of one of the cam abutment members on the cam follower along and up the rear surface of the lower cam during winding of the wire onto the spool.

Figure 9 is a cross-sectional view of the embodiment of the trimmer head of the present invention shown in Figures 1-8B.

10 is a perspective view of a spool for use in the embodiment of the trimmer head of the present invention shown in FIGS. 1-9 with a portion of the spool cut away to show the configuration of one of the thread receiver channels therein.

FIG. 11A is an enlarged cross-sectional view taken along line 11A in FIG. 10 .

11B is an enlarged fragmentary side view showing the guide surface adjacent the outlet end of the wire receiver channel.

11C is yet another enlarged partial side view showing the configuration of the wire receiver channel shown in FIG. Angular orientations are preferred.

11D is an enlarged fragmentary side view showing a preferred angular orientation of a wire receiver channel having a diamond-shaped cross-sectional configuration relative to a guide wall adjacent the outlet end of the receiver channel.

11E is an enlarged fragmentary side view showing a preferred angular orientation of a wire receiver channel having a triangular cross-sectional configuration relative to a guide wall adjacent to the outlet end of the receiver channel.

11F is an enlarged fragmentary side view showing the preferred angular orientation of a wire receiver channel having an elliptical channel wall configuration relative to a guide wall surface adjacent to the outlet end of the receiver channel.

11G is an enlarged fragmentary side view showing the desired orientation of the ribbed channel wall configuration relative to the guide surface adjacent the outlet end of the wire receiver channel.

11H is a perspective view of a portion of a length of specially configured cutting wire that may be used in the trimmer head of the present invention.

Figure 11I is a cross-sectional view taken along line 11I-11I of Figure 11H.

11J is an enlarged fragmentary side view showing a wire receiver channel and adjoining guide surface suitable for use with the cutting wire shown in FIGS. 11H and 11I.

11K is a perspective view of a portion of another exemplary length of specially configured cutting wire that may be used in the trimmer head of the present invention.

Figure 11L is an enlarged partial side view showing a wire receiver channel and adjoining guide surface suitable for use with the cutting wire shown in Figure 11K.

Figure 12 is a cross-sectional exploded view showing a modification of the housing portion of the trimmer head of the present invention and bolts for use with the modified housing.

Figure 13 is a cross-sectional view of one of the trimmer head eye rings.

14A is a cross-sectional view of a spool showing the inner end of a length of cutting wire held in one of the wire receivers and wound around the spool.

14B is a cross-sectional view of a spool with inwardly sloped wire receiver channels and showing the inner end of a length of cutting wire held in one of the wire receivers and wrapped around the spool.

14C is a partial cross-sectional view of a spool having a single wire guide wall and showing the inner end of a length of cutting wire exiting an adjoining wire receiver channel and being pulled against the guide wall surface.

Figure 15 is a bottom plan view of the spool showing the eye ring alignment marks on the spool.

Figure 16 is a bottom plan view of an alternate embodiment of a spool employing a second opposing pair of wire receivers to accommodate different sized wires.

Figure 17 is an enlarged exploded view of portions of an alternative embodiment of a housing and cam member that may be used in the present invention.

18 is an enlarged exploded view of yet another alternative embodiment of the housing and drive cam of the present invention similar to that shown in FIG. 17, except that the components forming the interference fit between the housing and cam members are Swap.

Figure 19 is an enlarged partial exploded view of yet another alternative embodiment of a housing and drive cam that may be used in the present invention.

Figure 20 is a perspective view from below of a second embodiment of the trimmer head of the present invention.

Figure 21 is a perspective view from above of a second embodiment of the trimmer head of the present invention.

FIG. 22 is an exploded perspective view of the various components making up the second embodiment of the trimmer head of the present invention shown in FIGS. 20 and 21 .

23 is a top plan view of a trimmer head housing of a second embodiment of the present invention.

Figure 24 is a bottom plan view of a trimmer head housing of a second embodiment of the present invention.

FIG. 25 is a cross-sectional view taken along line 25-25 in FIG. 24. FIG.

26 is a perspective view of the underside of the housing of the second embodiment of the present invention, showing the inner surface of the upper wall of the housing and the clutch slope formed in the housing.

Fig. 27 is a cross-sectional view of a bobbin according to a second embodiment of the present invention.

Figure 28 is a top plan view of a spool of a second embodiment of the present invention.

Figure 29 is a cross-sectional view of the second embodiment of the trimmer head of the present invention, showing the spool and trimmer head housing in drive mode.

30 is a cross-sectional view of a second embodiment of a trimmer head of the present invention showing the spool and trimmer head housing in an initial wire winding mode.

31 is a cross-sectional view of the trimmer head spool of the second embodiment of the present invention taken along line 31-31 of FIG. 27 and showing the inner end of the cutting wire wrapped around the spool.

Figure 32 is a perspective view from below of a third embodiment of a trimmer head of the present invention.

Figure 33 is a perspective view from above of a third embodiment of a trimmer head of the present invention.

Fig. 34 is an exploded perspective view from below of the various components making up the third embodiment of the trimmer head of the present invention shown in Figs. 20 and 21 .

Figure 35 is an exploded perspective view of the various components making up the third embodiment of the trimmer head, similar to Figure 34, but viewed from above.

Figure 36 is a cross-sectional view of a third embodiment of a trimmer head of the present invention showing the spool and trimmer head housing in the wire loading and bump feed modes.

37 is a cross-sectional view of a third embodiment of a trimmer head of the present invention, showing the spool and trimmer head housing in initial wire loading and drive modes.

Figure 38 is a bottom plan view of the upper portion of the housing of the third embodiment of the present invention.

FIG. 39 is a cross-sectional view taken along line 39-39 in FIG. 38. FIG.

Fig. 40 is a top plan view of a lower portion of a housing in a third embodiment of the present invention.

FIG. 41 is a cross-sectional view taken along line 41-41 in FIG. 40. FIG.

Figure 42 is a top view of the spool of the present invention showing the relative positioning of the lower cam follower relative to the upper cam follower, with the lower cam follower and wire receiver shown in phantom.

FIG. 43 is a cross-sectional view taken along line 43-43 in FIG. 42. FIG.

44 is a bottom plan view of the spool of the third embodiment of the trimmer head of the present invention, showing the relative positioning of the upper cam follower relative to the lower cam follower, and the upper cam follower and wire receiver. Shown in dashed lines.

Detailed ways

Referring now to the drawings in detail, there is shown in FIG. Not shown) on the extended end of the rotatable drive shaft 12. The trimmer head 10 generally includes a housing 14, a spool 16 for loading one or more lengths of coiled monofilament nylon cutting line 17, a cam member 18, a cam follower 20, a coil spring 22, a drive Bolt 24 and lock nut 25. The trimmer housing 14 is preferably formed by injection molding nylon 6 copolymer, and the trimmer housing 14 defines a circular upper wall 26, a cylindrical depending skirt 28, and a centrally disposed tubular extension 30 that An extension 30 depends from the upper housing surface 26 into the interior of the housing about the central axis of rotation "Y" of the head. The tubular extension 30 in the trimmer head housing 14 defines an annular outer shoulder 32 for the coil spring 22 and an axial passage 34 through which the drive bolt 24 extends. Channel 34 is configured to form a mating member with drive bolt 24 and cam member 18 . The upper end 36 of the channel 34 is preferably square in cross-section; the middle portion 38 has a constant radius and the lower portion 40 is hexagonal in cross-section.

As shown in FIGS. 2 and 9 , the drive bolt 24 defines a square head 24 a received in a correspondingly configured upper portion 36 of the channel 34 ; a cylindrical body portion 24 b extending through the center of the channel 34 . barrel portion 38 ; and lower shaft portion 24c extending from larger diameter body portion 24b and extending through and extending from lower hexagonal portion 40 of channel 34 . The drive bolt also defines an internally threaded cylindrical bore 24d extending axially through a solid portion of the head 24a and middle 24b for threaded engagement with the trimmer drive shaft 12 . Thus, by disposing the drive bolt 24 in the passage 34 and threadingly engaging the drive shaft 12, the drive shaft 12 is driven by the drive shaft due to the interference fit between the square head 24a of the drive bolt and the upper portion 36 of the passage 34 defined by the housing extension 30. The rotation of causes the drive bolt 24 and the housing 14 to rotate accordingly.

It should be noted that the cross-sections of the head of the drive bolt and the upper portion of the axially depending tubular member may be formed in shapes other than square to form the desired interference fit. For example, they could both be hexagonal so that rotation of the drive bolt can still be transmitted to the trimmer head.

The cam member 18 is preferably molded from a glass reinforced nylon 6 material, the cam member 18 is of unitary construction and in a preferred embodiment defines: a hexagonal head 42, an upper cam 44, a lower cam 46 and a lower cam 46. skirt 48. The head 42 is sized and shaped to be received into the lower portion 40 of the channel 34 in the extension 30 such that the counterclockwise direction of the housing 14 (indicated by arrow D in FIGS. 6 and 7 when viewed from above) (shown) rotation will transmit a corresponding rotation to the cam member 18. In a preferred embodiment, the head 42 of the cam member 18 and the lower portion 40 of the channel 34 are hexagonal in cross-section. It should be understood, however, that other non-circular (eg, square) shapes may be used to achieve the desired interference fit between the tubular extension 30 and the cam member in the housing.

In an alternative embodiment of the housing and cam member, the head 42A of the cam member 18A and the lower portion 40A of the tubular extension 30A in the housing 14A are cylindrical in cross-section and the interference fit between the housing and cam member By a plurality of ribs or lugs 45A extending vertically from the extension end 47A of the tubular extension 30A shown in FIG. 17 and a corresponding plurality of receiving grooves or holes 49A formed in the upper surface 51A of the cam 44A. supply. While at least one pair of ribs and grooves, or lugs and holes, is required to prevent relative rotation between the housing and cam member, it is more preferred to use more sets, equally spaced from a manufacturing and operational standpoint An array of four pairs of ribs and grooves, or lugs and holes, appears to be preferred. This configuration is shown in FIG. 17 . It should be appreciated that such an interference fit male member (eg, a rib or lug) could be provided on the extension end 47A of the tubular housing extension 30A shown in FIG. 17 or on the upper surface 51A of the cam 44A. . In either case, a corresponding female member (eg, slot or hole) can be provided in the other component. This reversed arrangement of components is shown in FIG. 18 . In yet another alternative embodiment, the head of the cam member can be eliminated entirely, and the required interference fit provided by the same or similar plurality of ribs or flanges 45A' and receiving slots or holes 47A'. This variation is shown in FIG. 19 . Likewise, corresponding male and female members can be reversed.

Both the upper cam 44 and the lower cam 46 are preferably of square configuration to define four likewise vertically disposed surfaces 44' and 46' on each cam. The portion of each of these surfaces that abuts a corner on the cam drive side or front side of either cam 44 or cam 46 defines a cam surface 44a or 46a when the cam rotates in the counterclockwise direction D (when viewed from above). Each cam surface on each cam is parallel to the axis of rotation Y of the head. As shown in FIG. 4A , the upper cam 44 and the lower cam 46 are rotationally offset by 45°. As shown in FIGS. 2 and 4B, the portion of the lower cam surface 46' that is perpendicular to and adjoins the cam surface 46a (thus lying on the rear side of the cam 46 when the cam member 18 is rotated counterclockwise) slopes upward. And defines a sliding surface 46b. The sliding surface 46b can be formed by an inclined linear surface or a curved surface. In the embodiment of the invention shown in Figures 1-9, the sliding surfaces are preferably radiused. As an example, in cam member 18, upper cam 44 and lower cam 46 each define surfaces 44' and 46' having a length of about 0.90 inches, and lower cam 46 has a thickness of about 0.20 inches. The slope on the rear sliding surface 46b defines a circular segment with a radius of 0.125 inches. Optionally, surface 46b can slope upward at an angle of about 25 degrees.

The cam member 18 also defines an axially disposed passage 50 that extends vertically through the cam member. The channel 50 has a first upper constant radius portion 50a adapted to receive the first constant radius portion 24b of the drive bolt 24 and a second (smaller) constant radius portion 24c adapted to receive the drive bolt 24 in a sliding fit with a smaller diameter. A small second constant radius portion 50b, the drive bolt extends through the channel.

The cam member 18 is disposed inside the trimmer head 10 of a cam follower 20, the configuration of which is best shown in Figures 5A and 5B. In order for the cam member 18 to properly align with the thread exit eyelet 78 in the trimmer head housing, a key 42' is molded into the side of the head 42 of the cam member, said key being received in the center housing. In a slot 40' in the lower portion 40 of the channel 34.

The cam follower 20 is preferably molded from the same material as the cam member 18, is of unitary construction and defines a cylindrical wall portion 52 circumscribing a chamber 54 and four equiangularly disposed projections defining An abutment member 56 radially extends from the upper inner end of the cylindrical wall 52 toward the inner side of the chamber 54 . Each abutment member 56 defines an angled cam abutment surface 56a and an inclined sliding surface 56b. Between the members 56 a relief area 60 is provided. An abutment surface 56a is located on the rear side of each abutment member, extends parallel to the axis of rotation Y of the cutting head and forms an angle of 135° with respect to the adjacent sliding surface 56b. To detachably secure the spool 16 to the cam follower, a plurality of outwardly projecting radial lugs 62 are equiangularly disposed around the cylindrical wall portion 52 of the cam follower 20 (four are shown). ).

The spool 16 defines an upper annular flange 70 and a lower annular flange 72 carried by a hollow cylindrical body portion 74 to define an annular region 76 between the flanges 72 and 74 for loading a coil wound around the body portion 74. A coil of flexible nylon cutting wire 17, such that, when assembled, the end 17' of the cutting wire extends outwardly through an eye ring 78 which is press-fitted through the side wall of the head formed by the housing skirt 28 The opposite hole 80 in. In the preferred head configuration shown in Figure 1, the portion of the housing skirt 28 adjacent the eye ring 78 is raised or sloped radially outward to protect the eye ring from foreign matter in use.

The body portion 74 of the spool 16 further defines: a circular striker 81 at the lower end of the body portion, an internal cylindrical chamber 82, a pair of diametrically opposed vertical locking passages 84 of identical configuration in the inner side wall of the body portion, and A pair of diametrically opposed and identically configured vertical guide passages 88 are arranged transversely relative to the locking passage 84 . As shown in FIG. 10 , the locking channel 84 terminates at a lower end in a slightly shallow offset 90 that terminates in a pair of opposing retaining holes 92 extending through the cylindrical body portion 74 . Each locking channel and guide channel are adapted to slidably receive an outwardly projecting radial lug 62 on cam follower 20 . The guide channel 88 differs from the locking channel 84 in that the guide channel is wider, of constant length and does not terminate in a hole. Preferably, the width of the guide channel is equal to the width of the locking channel plus the length of the offset portion 90 of the locking channel 84 .

When the lug 62 is aligned with the locking channel 84 and the guide channel 88, the spool 16 is secured to the cam follower 20 so that the end 17' of the cutting wire 17 protrudes radially from the spool 16 near the eye ring 78, and the spool 16 is pressed on the cam follower until the lug 62 reaches the lower end of the guide channel and locking channel. The spool is then rotated so that the lugs in the two locking passages 84 enter the slightly shallow offset 90 of the locking passages and the spool compresses the cam follower slightly until the two lugs reach the holes 92 so that the cam The resiliency of the follower material causes the lugs to snap into holes 92, securing the spool to the cam follower. In the locked position, the two lugs in the hole 92 are placed adjacent to the hole wall and the two lugs in the guide channel 88 abut the front wall of the channel so that during use, all four lugs will abut against it. The abutment wall enables corresponding rotation of the spool 16 with the cam follower 20 . To remove the spool, it is simply twisted relative to the cam follower and is easily axially removed from the housing when the lug is pulled back into the vertical portion of the locking channel.

The lug and channel configuration described above allows the spool 16 to be used with a cam follower having four equally spaced drive lugs 62 (as shown) or two opposing lugs if desired. Additionally, the driving force is evenly distributed between the four lobes 62 on the cam follower 20 . The provision of guide channels 88 in place of the second pair of locking channels 84 is for molding purposes only. Otherwise four identical locking channels can be used. If desired, the two guide channels in the spool can be widened such that each guide channel defines an arc length of approximately 95° so that the spool can accept a cam follower configuration having six equally spaced projecting lugs. Furthermore, the guide channels may be dimensioned such that two lugs in each guide channel abut the front wall of the channel, so that during use, the four lugs will again act as drive lugs to effect the rotation of the spool.

In order to provide quick loading of trimmer wire around the spool 16, the spool upper flange 70 is provided with a pair of opposed wire receivers 91 for gripping the inner ends 17″ of two separate lengths of cutting wire 17. Each receiver 91 Including a wire receiver channel 93 extending radially inwardly from an enlarged flared portion 93' adjacent the outer edge of the spool to the cylindrical body portion 74 of the spool. As will be described, the receiver channel 93 is constructed and oriented so that when cut The end of the wire is inserted into the receiver channel through the aligned eye ring and when pulled back at an acute angle towards the spool, tightly grips the cutting wire 17. Examples of channels 93 are shown in Figures 11A-11G, 11J, Shown in detail in Figure 11L, Figure 14A and Figure 14B.The cross-section of preferred channel configuration is polygonal, most preferably hexagonal, and from enlarged flared portion 93 ' to body portion 74 at an angle of about 5°. Inwardly tapered. The dimensions of the receiver channel depend on the size of the wire to be secured therein. By tapering the channel walls inwardly at an angle of about 5°, the channel can accommodate changes in wire size.

As an example, a tapered channel 93 that is hexagonal in cross-section and approximately 0.650 inches in length (excluding flared portion 93') has been successfully employed in trimmer head 10, adjacent parallel sides of the enlarged flared outlet end. The transverse dimension between them measured about 0.130 inches, and the transverse dimension across the end of the inner channel was about 0.075 inches (see, eg, FIG. 11A ). Conventional nylon cutting wire with diameters of 0.080 inches, 0.095 inches, and 0.105 inches can be received in the trimmer head, and the cutting wire is pulled from the outer end of the channel and wound around the spool as shown in Figures 14A and 14B , the cutting line can be tightly clamped by the receiver channel wall.

After the cutting line comes out of the receiver channel, in order to properly guide the cutting line inwardly, the downstream side or left side of the enlarged flared portion 93' of each receiver 91 is cut off to define the position shown in FIGS. 11B and 13-15. Flat guide walls 94a and 94b are shown. Surface 94a is substantially perpendicular to the central axis of the receiver channel and slopes slightly downward so that the central longitudinal axis "X" of the guide wall defines an angle relative to the horizontal of about 5°-10°, depending on the configuration of the bobbin. The abutment face 94b slopes inwardly to guide the wire towards the center of the spool. Thus, when a cutting wire is inserted into one of receiver channels 93 and pulled laterally against guide surface 94a and inwardly against guide surface 94b, the wire effectively forms an acute angle with the central channel axis. Additionally, the inner lower surface 95 of the flange extending below the channel 93 is rounded to avoid any abrupt surface differences on the spool adjacent to the wire receiver 91 and to direct the wire downwardly towards the lower flange 72, which This potential difference interferes with the correct winding of the wire. The channel 93 is preferably oriented about its central axis with opposite corners of the channel aligned with the central axis X of the guide wall 94a, as shown in Figure 11C.

By aligning the opposing channel corners with the central axis "X" of the guide wall 94a, the cutting line is pinched by the contracting channel walls as the wire is pulled from the channel and along the adjoining guide wall 94a. Due to the inherent strength of the nylon cutting wire, this pinching of the cutting wire occurs not only at the channel wall corner 93" adjoining the guide face 94a (see FIG. 11C), but also at the opposite corner at the inner end of the wire receiver channel. , thereby enhancing the clamping of the wire. Although the wire receiver channel has a cross-section configured as a hexagon that is misaligned with the central axis of the surface 94a as described above (see, for example, FIG. But the alignment shown in Figure 11C makes better use of the crimping effect created by the channel of the hexagonal cross-section configuration and is therefore preferred. Moreover, by aligning the central axis of the receiver channel 93 as shown in Figure 14B The guide wall 94a is angled inwardly by about 5°, rather than radially aligning the center axis of the channel with the center of the spool as shown in FIG. 14A relative to a line tangent to the flange at the outlet end of the channel. An acute angle is formed. As a result, when the cutting wire emerges from the receiver channel and is pulled against the adjoining guide wall 94b, it immediately forms an acute angle with respect to the central channel axis. This further increases the pinching effect of the channel wall on the wire , which in turn enhances the grip on the cutting wire. The firmer the receiver channel holds the wire, the easier it is for the user to achieve the initial winding of the wire spool without inadvertently pulling the wire out of the wire receiver channel. However, by The acute angle formed by sloping the central axis of the channel inwardly as described above adjoining the outlet end of the receiver channel may be too tight for a 0.105" diameter wire. Therefore, on trimmer heads designed to accommodate this larger size wire Among them, radially oriented channels are preferred.

Other line receiver channel configurations are shown in Figures 11D-11G. Figures 11D and 11E illustrate other polygonal configurations that are particularly suitable for use with the present invention. FIG. 11D shows a wire receiver channel 93a having a diamond-shaped cross-section. In order to maximize the wire crimping effect of such a channel, the channel should be oriented so that, as shown in the figures, the opposite corners on the minor axis of the cross-section lie on the longitudinal axis "X" of the guide wall. Figure 1 IE shows a wire receiver channel 93b having a triangular cross-section. To maximize the wire crimping effect of this channel configuration, one apex of the triangle defined by the channel at its outlet end is positioned on the longitudinal axis of the guide wall, adjacent to said guide wall, as shown in Figure 11E. Other polygonal cross-sectional configurations may also be employed in forming the wire receiver channel 93 of the present invention. However, it is generally believed that a channel formed by more than about eight sidewalls will be sufficiently round to not provide a desired gripping force to the wire. It has been found that circular radial channels do not provide sufficient grip on the wires as do channels defining a square cross-sectional structure when the flat sides of the square lie on the longitudinal axis of the guide wall. Other channel configurations may also be used. For example, a wire receiver channel 93c having an elliptical configuration, with the minor axis of the ellipse lying on the longitudinal axis of the guide wall channel face, as shown in FIG. 11F will provide sufficient gripping force on the wire. Irregularities in the channel walls can also be used. For example, FIG. 11G shows a wire receiver channel structure in which a plurality, preferably four, of longitudinally extending ribs 93"' are provided on an otherwise circular channel wall to grip the wire. To prevent damage to the ribs and and/or excessive wear on the wire, the ribs are preferably spaced apart so that the wire will abut two of the ribs equally at the inner and outer ends of the channel as shown in Figure 11G. Other such Irregularities in the sidewalls of the channel may include roughened surfaces and helically extending ribs (not shown) on the channel.

While the above described wire receiver channel structure is described and shown as extending along the entire length of the channel, and indeed such a structure is preferred, it should be noted that the gripping features of the channel need not extend the length of the channel. Acceptable clamping of the wires can be achieved by providing the wire clamping cross-sectional structure only at the outer ends of the channels. For example, the cross-section of the outer end of the channel may be hexagonal or rhomboid, while the remainder of the channel may be circular. As the wire is pulled laterally from the channel and against abutment guide face 94a and then inwardly against face 94b, the wire can be retained in the receiver channel by the constricted walls in the outer end of the channel. The length of the outer end of the channel of this configuration should be at least about 0.150 inches. When utilizing tapered wire receiver channels to receive wire of multiple sizes, only the inside of the wire needs to be tapered. Preferably, in such channel configurations, at least about fifty percent of the axial length of the channel (except flared portion 93") should taper.

In addition to clamping the cutting wire as described above by configuring at least a section of the exterior of the wire receiver passageway to hold the end of the cutting wire, the passageway can be configured to cooperate with a particular wire configuration so that when the wire is wound around the spool The fixation of the line is achieved through the cooperation effect or the embedding effect. For example, a flexible noise-reducing trimmer cord sold by Proulx Manufacturing, Inc. of Rancho Cucamonga, California, USA, under the name Ultra Quiet, is obtained by extruding two non-filamentous The polymer strands are formed by twisting the two strands together about a longitudinal axis in a cooling bath. After curing, the formed wire defines two overlapping columnar strands joined together in two opposing substantially V-shaped troughs along the wire and around the Line spiral extension. Compared with conventional wires of the same size rotating at the same speed, it was found that this wire construction can reduce noise to a large extent when rotating at the same speed. This wire construction is the serial number submitted on August 29, 2001 is the subject of co-pending US Patent Application No. 09/942,248. An example of such a noise reduction trimmer wire 517 is shown in FIG. 11H and its cross-sectional configuration is shown in FIG. 11J . By configuring the wire receiver channel 593 (see FIG. 11J ) to have a corresponding cross-section extending helically along at least the outside of the channel, when a wire is inserted into the channel through aligned outlet openings in the housing skirt and rotated , the channel walls will engage the wire and effectively helically engage the wire in the channel and secure the end of the wire to the spool.

Another example of a keyed wire and receiver channel is shown in Figures 11K and 11L. As shown here, a length of cutting wire 617 is provided with a protruding locking member 617a near one end of the wire. Member 617a may be of any convenient configuration. At least the end of the wire receiver channel 693 (see FIG. 11L ) is correspondingly configured to receive a wire with a protruding member, and an offset channel area is provided in the channel to allow the wire to rotate. The protruding member is thus received in the offset region. Thus, when the alignment member 617a is aligned with the outer end of the receiver channel 693, the wire is inserted and twisted, the length of wire is secured to the spool by the locking member being snapped so that it can be wound around the spool as described above. Wind the thread. In all such embodiments, the circular hole in the eye ring 78 in the side of the trimmer housing is substantially larger than the diameter of the cutting wire so that the locking member does not interfere with the extension of the wire through the eye ring.

Figure 14C shows another modified wire receiver that employs a single, inwardly sloped guide wall 94c positioned near the outlet end of the receiver channel. The single, inwardly sloped guide wall 94c similar to the inwardly sloped channel 17" shown in Figure 14B creates an acute angle between the central axis of the receiver channel and the guide surface adjacent the channel outlet. The single guide surface 94a guides the wire inwardly to the center of the spool faster than the aforementioned guide surfaces of the extension 94a and the slope 94b, and the smaller diameter spool reciprocates up and down faster than the larger diameter spool , so a single guide surface 94c is preferably used in smaller heads. Since smaller spools are generally not designed to receive larger diameter wires, the sharp bends created by guide surface 94c are generally not a problem.

The winding process of the wire is substantially the same in each variant of the wire receiver described above. To wind cutting wire onto the spool 16 , first align the wire receiver channel 93 in the spool with the eye ring 78 in the side of the housing 14 . The lower surface of the spool is preferably provided with printed markings such as arrows 85 to facilitate alignment, as shown in FIG. 15 . Next, the inner ends 17″ of the two separate lengths of cutting wire 17 are inserted through opposing eyelets 78 in the housing and pushed securely into aligned receiver channels 93 in the spool flange 70. In FIG. In the wire and channel configuration shown in 11L, the wires must be twisted together as described above. Next, the length of wire is bent at an acute angle and pulled toward the spool body portion 74 against the lateral guide walls 94 Next, while holding the housing in a stationary setting, the spool is manually rotated in a counterclockwise direction using the striker 81 as a handle. The preferably tapered and angularly arranged walls defining the receiver channel tightly grip the cutting wire The inner end prevents the inner end of the wire from being retracted from the channel. As the spool continues to rotate in a counterclockwise direction, the two lengths of cutting wire will wrap around the spool.

Manual rotation of the spool relative to the housing 14 in a counterclockwise direction will also cause a corresponding rotation of the cam follower 20 relative to the cam member 18 such that the sloped sliding surface 56b on the abutment member 56 is aligned with the opposite sloped surface on the lower cam 46. The sliding surface 46b abuts (see FIG. 8A ). Because surface 56b and surface 46b are sloped in opposite directions, continuing to rotate the spool counterclockwise while holding the housing stationary will cause abutment member 56 on the cam follower to press above sliding surface 46b on lower cam 46 . As the cam follower 20 moves upward relative to the cutting head housing 14, the spool 16 also moves upward. This movement is shown in Figure 8B. When the cam follower 20 is rotated to a position where the trailing corner of the lower cam 46 is aligned with the deactivated region 60 in the cam follower, the cam follower, and thus the spool 16, is in contact with the coil spring 22. Under force they will snap down to their original height relative to the housing, with cam surface 46a on the cam member aligned with cam abutment surface 56a on the cam follower. Therefore, when the two lengths of cutting wire are pulled inwardly through the eyelet 78 and wound around the spool, continued manual rotation of the spool relative to the housing in a counterclockwise direction will achieve continuous vertical clutching or disengagement of the spool in the housing. reciprocating motion.

When the two lengths of wire enter the spool area from opposite sides of the spool and are respectively directed to the center of the spool through the outlet ends of the wire receiver, even though the vertical distance the spool moves relative to the housing is less than the upper spool flange 70 and Lowering the distance between the spool flanges 72, this reciprocating motion of the rotating spool will also distribute the cutting line evenly around the spool. As a result, said length of thread will wind itself and fill the spool without tangling on the spool.

The above description of the trimmer head 10 and its components is based on the use of the head on a conventional rotary trimmer, in which a gearbox (not shown) typically transmits counterclockwise rotation to the drive. The shaft 12 is passed from there to the trimmer head. If the head is used on a trimmer without a gearbox or with a gearbox that turns the head clockwise, the front and rear surfaces on the cam and the cam follower abutment member will simply reverse . Thus, it is only necessary to reverse the orientation of the sliding surfaces on the cam and lower cam and on the abutment member 56 of the cam follower 20 . The cam surface 46a on the lower cam will still be on the front surface 46' of the cam 46, while the sliding surface 46b is on the rear side. Similarly, the cam abutment surface 56a will still be on the rear side of each abutment member, while the sliding surface 56b will still be on the front side.

Where the spool 16 has been described and shown to include two diametrically opposed wire receivers 91, if only the head of a single wire is required, one such receiver may be employed, or alternatively, a wire receptacle such as Multiple receivers spaced apart by distance. Also, two opposing pairs of receivers of different sizes may be employed to provide additional versatility to the cutting head. For example, in addition to the receptors shown in the drawings and described above, a second pair of linear receptors of slightly larger cross-sectional dimensions may be employed, wherein each pair of opposing receptors is perpendicular to the other so that the head balance. With this configuration, one pair of opposing receivers is sized to accommodate small diameter cutting wires, such as 0.065", 0.080", and 0.095" wire, while a second pair of receivers can accommodate larger diameter wires, such as 0.095 inches, 0.105 inches and 0.130 inches. For such applications, a second pair of markings should be printed on the upper surface of the spool to aid alignment of the second pair of wire receivers and wire outlet eyelets, and to indicate which pair of receivers holds the larger size wire and which A pair of receivers accommodates smaller sized lines. For example, a pair of smaller or narrower arrows 85' may be positioned perpendicular to a pair of opposing layer arrows 85" as shown in FIG. 16 to identify the size of the channel and align the cut lines for the length.

When fully assembled and loaded with the cutting line, the cam member 18 is located in the cavity 54 in the cam follower 20 with the hexagonal head 42 of the cam member 18 disposed in the channel 34 defined by the tubular extension 30 of the housing. Corresponding construction part 40. Coil spring 22 is disposed between and bears against shoulder 32 formed by housing extension 30 and the upper surface of cam follower 20 defined by cylindrical wall 52 and projection 56. surface, thereby depressing the cam follower 20 around the cam member 18 such that the underside of the abutment member 56 on the cam follower surrounds the upper surface of the skirt 48 of the cam member. A 5/16 inch or other suitable size push retainer or pal nut 25 (also known as a push nut or bolt retainer) slides onto the cylinder of the shaft portion 24c of the drive bolt 24. On the lower end, it is closely attached to the lower side of the skirt 48 on the cam member 18 . The shaft portion 24c of the drive bolt may be tapped or smooth, and a push-on fastener such as that shown and described in the 2003 edition of the McMaster-Carr Catalog on page 2982 is suitable for threaded or non-threaded bolts. By providing threads on the shaft portion 24c of the drive bolt, conventional threaded hex nuts can be used in field repairs if necessary and if push-type retainers are not available. However, the use of push-type holders enables the assembly of the trimmer head 10 to be simplified and fully automated, which is also the object of the present invention.

The spool 16 is arranged inside the housing 14, and the two lugs 62 on the spool 16 are placed in the offset portion of the locking passage 82, protruding from the hole 92, and the remaining two lugs are placed in the two guide passages 88. bottom. A striker 81 on the bottom of the bobbin 16 projects downwardly from the lower end of the housing 14 as shown in FIG.

The eyerings 78 preferably employed in the present invention are constructed of aircraft grade aluminum and each define at their inner ends an annular retaining flange 100 and a radial aperture for passing the cutting wire therethrough and into the receiver 91. Extended channel 102 . As shown in FIG. 13, the inner end 104 and outer end 106 of the channel 102 are rounded to eliminate any sharp corners and to accommodate the bending of the wire around the eye ring without crimping or undue stress on the wire. This eye ring configuration allows the eye ring 78 to be attached to the head 10 during an automated process and held in place during use by the flange 100 and the centrifugal force exerted thereon.

In operation, rotation of the drive shaft 12 on the trimmer causes a corresponding rotation of the housing 14 and cam member 18 due to the fit between the drive bolt 24 , the drive shaft 12 and the tubular extension 30 of the housing 14 . The cam follower 20 is pressed down relative to the cam member 18 so that the underside of the protrusion 56 on the cam follower abuts the skirt 48 of the cam member 18 and the cam surface 46a on the lower cam 46 is aligned with the An abutment member 56 on the follower 20 defines an abutment surface 56 and bears against said abutment surface 56, thereby causing a corresponding counterclockwise rotation of the cam follower and the spool carried by said cam follower. , as seen above in Figure 6. By having the skirt 48 of the cam member 18 have a vertical length of about 0.5 inches, rather than employing a thinner disk configuration, wobble of the cam member in the cam follower during use can be minimized.

After pressing the rotary striker 81 on the bottom of the spool 16 against the ground or other rigid surface, pressing down on the trimmer housing 14 and the cam member 18 secured to the trimmer housing by the driven bolt 24 and retainer 25 compresses the coil spring 22 And disengages the lower cam 46 from the abutment surface 56a on the cam follower. When the cam member 18 moves downward until the lower end 30' of the tubular extension 30 abuts the upper surface of the upper cam 44, the lower cam comes out of its way in engagement with the cam abutment surface on the cam follower and pushes the upper cam to the upper surface of the upper cam 44. Cam surface 44a on 44 feeds into the passage of cam abutment surface 56a. This slows the rotation of the cam follower 20 relative to the cam member 18 , and thereby slows the rotation of the spool 16 relative to the cam member 18 and housing 14 . When the upper cam surface 44a hits the abutment surface 56a, the corresponding rotation of the cam and cam follower resumes (see FIG. 7). During this time, however, the cam member and housing rotate 45° relative to the cam follower and spool.

Once the force of the impact is lost, the coil spring 22 returns the spool and housing to their original positions, releasing the engagement of the cam surface 44a on the upper cam 44 with the abutment surface 56a of the cam follower, engaging the cam surface 46a again, causing the cam The member and cam follower, and thus the spool and housing, rotate relative to each other another 45°, resulting in a total of 90° rotation during the collision, regardless of the duration of the collision. During relative rotation, the spool lags relative to the housing, and centrifugal force causes a predetermined amount of fresh cutting wire to be released through opposing eye-rings 78 in the trimmer housing. Next, the worn strands are severed by a conventional cutting blade (not shown) carried by a protective canopy (not shown) mounted above the trimmer and spaced radially from the rotating head 10 .

It should be noted that cam follower 20 includes a deactivated region 60 between projections 56 so that when cam 44 and cam 46 are in the wire feeding position relative to the cam follower as shown in FIGS. 6 and 7 , cam 44 And cam 46 is vertically slidable relative to cam follower 20 and allows the spool to reciprocate during loading of the line but not at other times. In the position shown in FIG. 7 , cam 44 and cam 46 can slide upwardly off cam surface 44 a , while in FIG. 6 they can slide downwardly off cam surface 46 a . Cams with three or more or differently configured cam surfaces are also possible, while cams 44 and 46 with four sides are a practical compromise between surface area contact, ease of processing and ideal wire feed. Also, instead of a square cam defining a cam and sliding surfaces abutting the corners of the cam, the angularly offset upper and lower cams may each have four concave sidewalls and define four corners at the four corners. radial projections or tangs that are equally spaced. In this way, the leading and trailing edges of the tang will define the camming and sliding surfaces. Such a cam member can function without modification of the cam follower 18 .

In the preferred embodiment of the cutting head housing 14, a recessed area 99 is provided in the housing skirt 28 to form a "window" for a label. Since the surface 99' on which the label is to be applied is offset from the remainder of the housing skirt, the label is protected during use.

An alternative embodiment of a housing and drive bolt that may be used in the present invention is shown in FIG. 12 . These embodiments differ from the previous embodiments in that the drive bolt 124 is pushed up into the lower hexagonal portion 140 of the inner housing extension 130 for assembly. The tubular extension 130 of the modified housing 114 defines a cylindrical upper portion 136 having a raised annular ridge 137 extending around its interior sidewall and an extended hexagonal lower portion 140 . Drive bolt 124 defines: a cylindrical upper portion 124a having an annular groove 124e formed therein; a hexagonal middle portion 124b; The shaft portion 24c can also be threaded or smooth. After the drive bolt 124 is inserted into the tubular extension 130, a ridge 137 in the upper portion of the bolt provides an interference fit to retain the bolt in the housing. If the bolts are pushed into place immediately after the housing is formed, the nylon material will shrink around the bolts as it cools, enhancing the hold. However, even if the bolt is inserted into the casing extension long after the casing has been formed and cooled, the engagement between the bolt and the casing extension will hold the bolt in place.

The upper cylindrical portion 124a of the drive bolt 124 has a threaded cylindrical hole 124d extending axially through the upper cylindrical portion 124a and to the hexagonal portion 124b for threaded engagement with the drive shaft 12 of the trimmer, as in the previous embodiment . However, if desired, the bolt 124 may be provided with a threaded extension (not shown) adapted to engage a trimmer drive shaft having a threaded female end. The same variation applies, of course, to the drive bolt 24 . The hexagonal portion 124b of the drive bolt is received in the upper portion of the hexagonal portion 140 of the housing extension 130, and after the cam member 18 and the cam follower 20 are fixed, the hexagonal portion 124b is set. into tight abutment against the hexagonal head 42 of the cam member. As in the previous embodiments, the shaft portion 124c of the drive bolt 124 protrudes downward beyond the end of the housing extension 130 and is used by the cam member 18 to engage the push retainer 25 . The rest of the elements are also the same as the corresponding elements of the previous embodiment. As with the previous embodiments, this embodiment can be assembled in a fully automated process and using a minimum of components, requiring no chemical adhesives that are heat sensitive and/or hinder component replacement.

A second embodiment of the present invention is shown in FIGS. 20-31 , wherein a wire loading mechanism is used in a hand trimmer head 100 . Head 100 is also mounted on the extended end of a rotatable drive shaft on a gasoline powered or electric rotary trimmer. The trimmer head 100 generally includes a housing 114, a spool 116 for loading one or more lengths of coiled monofilament nylon cutting line 17, a coil spring 122, a drive bolt 124 and a mechanism for securing the spool 116 to the Wing nut 125 of trimmer head housing 114.

Preferably, the trimmer housing and spool are formed from the same material as the corresponding components of the previous embodiments. Housing 114 defines an upper circular wall 126 , a cylindrical skirt 128 depending therefrom, and a centrally disposed tubular extension 130 . The tubular extension 130 is aligned with the head's central axis of rotation "Y" and includes a depending portion 130a and an upwardly projecting portion 130b. The tubular extension 130 is configured to receive the drive bolt 124, and the upward projection 130b is preferably square in cross-section to match the square head 124a of the bolt, and the radius of the depending portion 130a is a decreasing constant to receive the drive bolt. The columnar body portion 124b. Lower shaft portion 124c extends down and through the interior of the housing and then to the spool where it is threadedly engaged by wing nut 125 as will be described below (see, eg, FIG. 29 ).

The drive bolt 124 also defines an internally threaded cylindrical bore (not shown) that extends axially through the head and the solid portion of the middle of the trimmer for threaded engagement with the trimmer's drive shaft, as in As in the collision supply head of the first embodiment. Thus, by placing the drive bolt 124 in the tubular extension 130 of the trimmer head housing 114 and threadingly engaging the drive shaft, rotation of the drive shaft is due to the square head 124a of the drive bolt and the upper portion of the extension 130. The interference fit between 130b causes the drive bolt and housing to rotate accordingly (typically counterclockwise). Furthermore, the cross-sections of the head of the drive bolt and the upper portion of the tubular extension in the housing may be shaped differently than square to provide the desired interference fit.

The trimmer head housing 114 also defines a pair of opposing slots 180 in the depending cylindrical skirt 128 . Slot 180 is open at its bottom end and is adapted to slidably receive a pair of opposing outlet eyerings 178 with a press fit. Optionally, as in the previous embodiment, the eye ring may be press fit through a hole in the housing skirt. Also, it is preferred that the portion of the housing skirt 128 adjacent the eye ring is raised or sloped outward to protect the eye ring from foreign matter during use. A plurality of radially protruding cooling ribs 115 are formed on the upper wall 126 of the housing 114 , and the cooling ribs extend upward along the upper portion 130 b of the tubular extension 130 . Preferably, the cooling ribs 115 are provided with sharpened surfaces 117 for cutting weeds that may wrap around the drive shaft near the trimmer head during use. A plurality of equidistantly spaced drive lug receiving apertures 119 extend axially through the upper wall 126 of the trimmer housing, the apertures 119 being adapted to receive upwardly extending projections on the spool defining drive lugs 121, as will be as described.

The trimmer head spool 116 defines an upper annular flange 170 and a lower annular flange 172 carried by a cylindrical body portion 174 to define an annular region 176 between the flanges 170 and 172 for loading A coil of flexible nylon cutting wire 17 wrapped around body portion 174 such that the end 17' of the cutting wire will extend outwardly through exit eyelet 178 when assembled. The spool also includes a lower body portion 175 depending from a lower flange 172 . The spool 116 also includes a depending cylindrical extension 131 which, when assembled, aligns with the tubular extension 130 on the trimmer head housing 114, as shown in FIG. Threaded lower shaft portion 124c extends through extension 131 and into a region circumscribed by lower body portion 175 of the spool where the shaft portion is threadably engaged by wing nut 125 .

The coil spring 122 extends around the depending extension 131 in the spool, abuts against and extends between the underside of the upper spool flange 170 and the annular concave surface 125' in the upper portion of the wing nut 125. So secured, the spool 116 and trimmer head housing 114 are urged together by the coil spring 122 . In this secured position, drive lug 121 projects upwardly from the upper surface of flange 170 into drive lug receiving aperture 119 in the trimmer head housing, securing the spool to the trimmer housing so that the housing The rotation by the drive bolt is transmitted to the spool. To remove the spool from the trimmer head housing, it is only necessary to thread the wing nut 125 off the threaded lower shaft portion of the drive bolt.

In order to enable the line of the trimmer to be wound around the spool 116 without removing the spool from the housing, the upper spool flange 170 is provided with a pair of opposing inner ends 17″ for holding two separate lengths of cutting line 17. Wire receiver 191. The size and configuration of the spool 116 is such that the flange 170 is in planar alignment with the wire outlet eyelet 178. Each wire receiver 191 comprising a wire receiver channel 193 is identical to the wire receiver 91 in the previous embodiment. Have the same construction and function in the same way.Its size can vary slightly according to the size variation of each spool and the diameter variation of the cutting wire for which the head is designed.

In addition to including a cord receptacle 191 on the spool 116 , the inner surface 126 ′ of the upper wall 126 of the trimmer head housing 114 is provided with a plurality of arcuate slopes 123 . One such ramp adjoins each lug receiving hole 119 and extends from each lug receiving hole 119 to the next hole, as shown in FIG. 26 . In the embodiment of the trimmer head 100 as shown, the ramps 123 are configured such that they follow an arcuate path, respectively, and begin at a position adjacent laterally and slightly below the inner surface 126' of the upper housing wall 126 toward the Extending obliquely downward, defining a vertical step 119' at the rear side of the lug receiving aperture. The ramp 123 then transitions smoothly back to the inner surface 126' of the upper housing wall near the next lug receiving aperture 119 . Thus, when gripping the lower body portion 174' of the spool 116 and rotating the spool in a counterclockwise direction while holding the trimmer head housing stationary, the drive lugs move from each side of the upper wall of the trimmer head housing. The hole 119 moves down the ramp around the step 119' to the inner surface 126' of the upper housing wall and then moves up under the action of the spring 122 to the next position in the lug receiving hole. Thus, continued rotation of the spool relative to the housing will cause the spool to clutch or reciprocate within the housing as described above in the discussion of the first embodiment of the invention.

The step 119' defined by the vertical spacing between the outer surface of the housing upper wall 126 and the upper end of the ramp 123 prevents any chatter or backlash of the wire during use causing reverse rotation of the spool and accidental payout of the wire. For this purpose, vertical steps with a height of about 0.015 inches to 0.025 inches are employed. In order for the driving lug 121 to pass smoothly over the step 119' under the action of the manually rotating spool 116, the upper surface of the lug (in the driven position, said upper surface is substantially flush with the upper surface of the housing wall 126) 121' into a circle. A surface 121' having a radius of approximately 0.030 inches is employed. Although the ramp 123 vertically aligns the upper spool flange 170 and thus the line receiver 191 therein with the eyelet 178 as the drive lug 121 rotates off the ramp and onto the inner housing wall surface 126', Preferably, the spool 116 is sized relative to the trimmer housing 114 so that when the drive lug 121 is disposed in the lug receiving aperture, the opposing wire receiver is radially aligned with the eyelet. In either case, radial alignment between the receiver and the eyelet is readily achieved.

Thus, as with the previous embodiment, the length of cutting wire 17 is wound around the spool by pressing the extended end of the wire into the wire receiver and rotating the spool relative to the housing as described above. As the spool rotates, the length of wire bends sharply toward the inside of the spool as it exits the receiver channel and is pulled against the flat lateral guide walls adjacent the channel exit. As the spool continues to rotate, the spool reciprocates vertically relative to the housing as the drive lug repeatedly moves along the downwardly sloping ramp and snaps upward into the next receiving aperture. As a result, the wire is caused to be evenly wound on the bobbin, while entanglement of the wire is avoided, as in the previous embodiment.

Finally, as with the previous embodiments, various modifications in wire receiver configuration, number and size can be used in the manual head 100 to provide the desired grip on the wire and to receive wire of various sizes, Of course also suitable for the number of cutting lines extending from the cutting head. Additionally, the orientation of drive lug 121 , aperture 199 and ramp 123 can be changed or reversed. For example, the drive lug can be formed on the upper housing wall and the hole and abutment ramp can be formed in the upper surface of the spool.

A third embodiment of the invention is shown in FIGS. 32 to 44 . The trimmer head 200 shown in the figures is a bump feed type head having the drive mechanism and wire feed mechanism disclosed in U.S. Patent No. 4,959,904 but modified to include the rapid Line loading features. As will be shown, the main difference between the trimmer head 200 and the impact feed head 10 of the first embodiment is that in the trimmer head 200, the cam, driven by an axially mounted cam member 18 within the head 10 and The cam abutment and sliding surfaces defined by the cam follower 20 are molded directly into the spool in the trimmer head 200 and the trimmer head housing.

Trimmer head 200 includes: housing 214 , spool 216 , coil spring 222 and drive bolt 224 . The housing includes an upper portion 214a and a lower portion 214b that are releasably secured together about the spool. Furthermore, the trimmer head housing and spool are preferably formed from the same material as the corresponding components of the previous embodiments. The upper housing 214a defines an upper circular wall 226 , a cylindrical skirt 228 depending therefrom, and a centrally disposed tubular extension 230 . The extension 230 is axially aligned with the central axis of rotation of the head and includes a depending portion 230a and an upwardly projecting portion 230b. Additionally, the tubular extension 230 is configured to receive a drive bolt 224 having an upper portion 224a that is circular in cross-section and a lower portion 224b that is hexagonal in cross-section to match the hexagonal shape of the tubular extension. The lower part 230a matches. The lower portion of the drive bolt and tubular extension in the housing may also be squared or otherwise configured to provide the desired interference fit between the drive bolt and housing. The drive bolt 224 is secured in the tubular extension 230 by heat shrinking the extension 230 around the bolt. An annular groove 224e is provided around the drive bolt to create an interference fit between the bolt and the housing as the plastic housing material contracts to facilitate securing the bolt to the housing. Other means may also be used to secure the drive bolt to the housing. The drive bolt 224 also defines an internally threaded cylindrical bore 224f extending axially therethrough for threaded engagement with the drive shaft of the trimmer as in the previous embodiments. A second tubular extension 211 radially spaced from a depending portion 230a of the extension 230 extends downwardly from the inner surface of the upper housing wall 226 to define an upper annular seat 213 for the coil spring 222 at its lower end.

The upper portion of the housing 214 also defines a pair of opposing slots 277 in the depending cylindrical housing skirt 228 . As with the previous embodiment, the slot 280 is open at its lower end and is adapted to receive a pair of opposing metal outlet eyerings 278 with a press fit. Optionally, as in the first embodiment, the eye ring can be press fitted through a hole in the housing skirt. In addition, the portion of the housing skirt adjacent to the eye ring is preferably elevated or outwardly inclined to protect the eye ring from foreign matter in use, and a plurality of radially protruding cooling ribs 215 are formed on the upper housing on the upper wall 226 . A plurality of equiangularly disposed and outwardly projecting radial projections 233 are also provided at the lower end of the skirt 228 to secure the lower housing portion 214b to the upper portion 214a as will be described.

The upper wall 226 of the trimmer head housing has a raised central portion 227 and defines a recessed area 229 within said central portion. As shown in FIG. 38 , the peripheral wall surface 231 extending around the concave region 229 defines four equiangularly arranged protrusions 244 , and the protrusions 244 protrude radially inward from the wall surface 231 . Each protrusion defines a pair of angularly disposed surfaces 244' that intersect at 135° and are parallel to the axis of rotation of the head. These protrusions are similar in construction to the protrusions 56 on the cam follower 20 of the first embodiment, though larger. Here, however, these protrusions will define a cam surface rather than a cam abutment surface.

The front surface on each protrusion 244 defines an upper cam 244a (counterclockwise as viewed from above). Each rear surface defines an upper sliding surface 244b. The surface of each cam is also parallel to the axis of rotation of the head. Especially on small size heads, said upper sliding surface 244b may be sloped downwards, preferably rounded, to facilitate loading lines as described below.

The lower housing portion 214b of the trimmer head 200 defines: an enlarged circular opening 235 located on the underside of the lower housing portion, an annular horizontal surface 237 disposed around the opening 235, and an upper surface adjacent to the lower housing portion 214b. A plurality of equiangularly disposed slots 239 (four shown) of surface 241 for receiving a corresponding number of locking protrusions 233 on upper housing portion 214a. The slot 239 is provided with a narrower offset 239', as shown in Figure 35, and at least one locking projection 233a is mounted on the cantilevered portion 228' of the housing skirt so as to be resilient so that when rigidly locked The protrusions 233 are inserted into the three slots in the lower housing portion, pressing the resilient protrusions 233a radially inward to press them into the remaining aligned slots, and rotate counterclockwise relative to the lower portion of the housing When the upper part of the housing is removed, the locking projection will move into the offset of the slot, thereby releasably securing the two housing parts together.

As shown in FIG. 40 , the lower housing portion 214b further defines four equiangularly disposed protrusions 246 on the annular surface 237 adjacent the opening 235 . Angularly disposed surface 246' on protrusion 246 defines an angularly disposed lower cam 246a and lower sliding surface 246b, similar to surface 244' in protrusion 244 in upper housing portion. The lower cam 246a is located on the raised front surface and extends parallel to the axis of rotation of the cutting head, also at an angle of 135° to said abutting sliding surface. The sliding surface 246b may also be rounded upward in the same manner as the sliding surface 46b on the lower cam 46 in the first embodiment. However, in a preferred embodiment, the sliding surface 246b on the lower projection 246 is angled not at 135° relative to the cam surface 246a, but rather at a smaller angle as shown in FIG. Preferred sloped configuration defined by the spool on the front side of the cam follower.

The spool 216 in the trimmer head 200 defines an upper flange 270 and a lower flange 272 carried by a cylindrical upper body portion 274, thereby defining an annular region 276 between the upper flange 270 and the lower flange 272, which The area is used to carry the coil of flexible nylon cutting wire 17 wrapped around the body portion 274 so that, when assembled, the end 17' of the cutting wire will extend outwardly through the outlet eyelet 278. A cylindrical chamber 243 open at the upper end is arranged around the central axis of rotation. An annular upstanding wall 245 is disposed in the lower end of the chamber 243 to define an annular spring receiving area 247 and a lower spring seat 247'. The lower body portion 275 of the spool terminates in a striker 281, and radial flanges 249 extend outwardly from the lower spool body portion to prevent debris from becoming trapped between the spool 216 and the lower housing portion 214b (see FIG. 36). When head 200 is assembled, coil spring 222 extends around extension 230, abuts against and extends between upper seat 213 formed in upper housing portion 214a and lower spring seat 247' in spool 216, as shown in FIGS. 36 and 37 shown in . The striker 281 on the bottom of the spool protrudes through the opening 235 in the bottom of the lower housing portion 214b so that the striker 281 can strike the ground to let out additional cutting wire through the opposing eye ring 278, as in the first embodiment. Show.

The upper flange 270 of the spool 216 defines an upper cam follower 256 on its upper surface, and the lower spool flange 272 defines a lower cam follower 257 on its lower surface, as shown in FIGS. 42-44 . Although other configurations are possible, the cam followers are preferably of square configuration, distributed to define four vertical surfaces 256' and 257', and offset by 45° relative to the central axis of rotation of the trimmer head. Cam abutment surfaces 256a and 257a defined by the front surfaces of the upper and lower cams are also parallel to the axis of rotation of the head. The front surface of the lower cam follower defining the sliding surface 257b may slope upwards near the upper corner to provide smoother clutching if necessary. Also, the front surface of the upper cam follower may also be sloped downward to facilitate the feed line. The downward slope of the trailing edge 256b is believed to be necessary for smaller heads where the length of each cam follower surface is short, otherwise, the relative rotation of the spool and housing during wire winding may be made more difficult. difficulty. It may also prove advantageous to slope the rear surfaces of the upper and lower cams.

In a preferred construction, the sliding surface 257b on the lower cam follower is defined by a sloped ramp, as shown in Figures 34, 42 and 44, which is more gradual than the slope provided by a radiused surface. In the process of winding the cutting wire onto the bobbin, the bobbin can be clutched more smoothly. As noted above, when the spool 216 is moved up when the trimmer head hits the ground to pay out new line, and during manual rotation of the spool to wind the cutting line onto the spool, the bumps on the protrusions 246 The corresponding sliding surface 246b defined by the lower housing portion slopes inwardly more steeply than the corresponding surface on the protrusion 244 on the upper housing portion 214a to provide more space adjacent to the sliding surface on the protrusion 246 to accommodate the protrusion. These inclined bevels on the 224.

The operation of the bump feed mechanism provided by the upper and lower cams and cam followers is explained in detail in referenced Patent No. 4,959,904. It should be noted, however, that the cam followers in head 200 carried by the upper and lower spool flanges are referred to as upper and lower cams in the referenced patent, but the upper and lower cams in head 200 are referred to in In the referenced patent it is referred to as a cam follower. As explained in more detail in the cited reference, in use, the lower cam 246a on the lower housing portion 214b is aligned with and abuts a lower cam abutment surface on the rear surface of the lower cam follower 257 . Thus, when the housing is rotated in a counterclockwise direction by the trimmer drive, the spool rotates with the housing. In this drive position, the upper cam 244a is spaced upwardly from the upper cam follower 256, so only the drive force is generated by the lower cam. When the striker 281 is pressed against the ground, the spool 216 is forced upward in the housing to disengage the lower cam abutment surface 257a on the lower cam follower from the lower cam 246 and allow the upper cam follower 256 The upper cam abutment surface 256a on the top is aligned and immediately abuts on the upper cam 244a, so that the driving force is generated only by the upper cam. When the striker 281 is lifted from the ground, the coil spring 222 forces the spool downward to disengage the upper cam follower from the upper cam and reengage the lower cam follower from the lower cam. Thus, as with the first embodiment of the invention, each impact on the ground produces the effect of a relative rotation of the bobbin and housing by 90°, regardless of the duration of the impact. During this relative rotation, centrifugal force causes a predetermined amount of fresh cutting wire to be released through opposing eyelets 278 in the trimmer head housing.

In order to provide quick loading of the trimmer's line around the spool 216, the upper spool flange 270 is provided with a pair of opposed line receivers 291 to hold the inner ends 17" of the two separate lengths of cutting line 17. Dimensions of the spool 216 And the configuration is determined to make the upper flange 270 on the spool planarly aligned with the eye outlet hole 278.Each thread receiver 291 comprising a thread receiver channel 293 has the same construction as the thread receiver in the previous embodiment, and uses the same In addition, the size can be slightly changed according to the size variation of each spool and the diameter variation of the cutting wire for which the head is designed. The above-mentioned cam, cam abutment surface and sliding surface are used to provide the head The cam, the abutment and the sliding surface in the first embodiment are matched in substantially the same manner so that the bobbin reciprocates in the housing so that the wire is evenly distributed on the bobbin. When the bobbin 216 is clamped by the striker 281, And when rotated in a counterclockwise direction relative to the housing, the lower sliding surface 257b on the lower cam follower 257 will abut the rear surface 246b on the lower boss 246, causing the spool to move upward relative to the housing, thereby compressing the coil spring 222. As the spool continues to be manually rotated, the corners of the lower cam follower 257 will ride over and clear the protrusion 246 in the lower portion of the housing, and the spring will thus cause the spool to snap downward so that the lower protrusion and lower The cam abutment surfaces are again planarly aligned. Since the upper sliding surface on the upper projection 244 abuts against the front (sliding) surface on the upper cam follower 256, each time the coil spring 222 engages the spool 216 downwards, The cutting wire is wound onto the spool, so it can be shown that having the front surface 244b of the upper projection 244 and/or the front (sliding) surface 256b of the upper cam follower 256 beveled provides a spool relative to the housing during loading of the wire. The smoother rotation is beneficial.

As noted in referenced Patent No. 4,959,904, the bump feed mechanism provided by the cam and cam abutment surface need not be limited to square cam followers (or cams as noted in the referenced patent). The same is true for trimmer head 200 . For example, the upper and lower cam followers formed by the upper and lower bobbins may have three faces or five faces, as shown in FIGS. 12-15 of reference Patent No. 4,959,904. Three-sided or five-sided cam followers can cooperate with equal amounts of cam abutment members in the upper and lower housings, as shown in the referenced figures. Otherwise, the function, fit and operation of such cams and cam followers is substantially the same as in the aforementioned and referenced patents.

Various changes and modifications can be made in the present invention without departing from the spirit and scope of the invention. A spool such as employed in the present invention may be formed with a single flange around which the wire will be wound around the body of the spool between the flange and a portion of the housing. A single wire receiver or multiple wire receivers can still be provided in a single flange. These and other changes and modifications are intended to be a part of the present invention so long as they come within the scope of the appended claims.

Claims (25)

1. trimmer head, the flexible line of cut of its at least one length in flexible line rotary trimmers uses, and described trimmer head comprises:

Housing, it is suitable for operatively being connected to rotary trimmers so that described trimmer head rotates, and described housing limits the sagging skirt section of tubular, has at least one outlet opening in the sagging skirt section of described tubular:

Bobbin, it operatively is connected to described housing, in drive pattern, to rotate around common axis with described housing, and rotate with respect to described housing in the online winding pattern, described bobbin comprises cylindrical body part and from radially-protruding at least one flange of described body part, thereby around described body part and in abutting connection with described flange limit line of cut storage area, being operatively connected between described bobbin and the described flange makes and produce moving mutually along described common rotating shaft line when described bobbin rotates with respect to described housing between described bobbin and described housing; And

At least one line receiver, it is formed in the described flange, described receiver comprises the passage that extends internally, described passage limits when described bobbin is relative with described housing can aim at the outer end of the outlet opening in the described skirt section when rotating, and wherein, the outside at least of described passage formed by a plurality of walls, thereby cross section is a polygon, described wall limits such surface, promptly be inserted in the described passage by described outlet opening in the end of described line, the part of the described line that extends from described passage is by the described body part guiding towards described bobbin, and described bobbin is during with respect to described housing rotation, the line of cut of described surperficial clamping certain-length.

2. trimmer head according to claim 1, the cross section of the described at least outside of the described passage in the wherein said receiver is a hexagon.

3. trimmer head according to claim 1, the inner at least inwardly convergent of the described passage in the wherein said receiver.

4. trimmer head according to claim 2, the inner at least inwardly convergent of the described passage in the wherein said receiver.

5. trimmer head according to claim 1, it comprises in abutting connection with the line spigot surface of the described outer end of described passage, inwardly guides from the described part of the described line of described passage extension with the described body part towards described bobbin.

6. trimmer head according to claim 1, wherein said passage limits the linear center axis and described passage radially extends through described line receiver, makes the described central axis of described passage and described common axis intersect.

7. trimmer head according to claim 1, wherein said passage limits the linear center axis, and described axis is at the place, described outer end of described passage and the tangent line formation acute angle of described flange.

8. trimmer head according to claim 1, the outside at least cross section of the described passage in the wherein said receiver is a rhombus.

9. trimmer head according to claim 1, the cross section of the described at least outside of the described passage in the wherein said receiver is a triangle.

10. trimmer head according to claim 5, wherein said passage limits the linear center axis, and wherein, at least a portion of the described outer end of the described passage in the described line receiver of the adjacency of described line spigot surface is linear, and limit the central longitudinal axis along its extension, described central longitudinal axis intersects with the described central axis of described passage.

11. trimmer head according to claim 5, the first of the described outer end of the described passage in the described line receiver of the adjacency of wherein said line spigot surface extends laterally from the described outer end of described passage, and the second portion of described line spigot surface is from described first side direction and extend internally.

12. trimmer head according to claim 5, at least a portion of the described outer end of the described passage in the described line receiver of the adjacency of wherein said line spigot surface is linear, and limit central longitudinal axis along its extension, and wherein, at least the described outside of described passage is formed by a plurality of pinch wall, limiting corresponding a plurality of passages bight, described passage is oriented to and makes the described longitudinal axis of described part of described spigot surface intersect with the described linear center axis of described passage and at least one bight in the described passage bight.

13. trimmer head according to claim 12, the cross section of the described at least outside of the described passage in the wherein said receiver is a hexagon.

14. trimmer head according to claim 12, the cross section of the described at least outside of the described passage in the wherein said receiver is a rhombus.

15. trimmer head according to claim 12, the cross section of the described at least outside of the described passage in the wherein said receiver is a triangle.

16. trimmer head according to claim 12, the inner at least inwardly convergent of the described passage in the wherein said receiver.

17. trimmer head according to claim 12, the described central axis of wherein said passage also are defined as acute angle with respect to the described longitudinal axis of the described part of described spigot surface.

18. a trimmer head, the flexible line of cut of its at least one length in flexible line rotary trimmers uses, and described trimmer head comprises:

Housing, it is suitable for operatively being connected to rotary trimmers so that described trimmer head rotates, and described housing limits the sagging skirt section of tubular, has at least one outlet opening in the sagging skirt section of described tubular;

Bobbin, it operatively is connected to described housing, in drive pattern, to rotate around common axis with described housing, and rotate with respect to described housing in the online winding pattern, described bobbin comprises cylindrical body part and from radially-protruding at least one flange of described body part, thereby around described body part in abutting connection with described flange limit line of cut storage area, being operatively connected between described bobbin and the described flange makes and produce moving mutually along described common rotating shaft line when described bobbin rotates with respect to described housing between described bobbin and described housing; And

At least one line receiver, it is formed in the described flange, described receiver comprises the passage that extends internally, described passage limits the outer end that can aim at the outlet opening in the described skirt section when the relative rotation of described bobbin and described housing, and wherein, at least the outside cross section of structure like this that limits of described passage, promptly, when the described end of described line is inserted in the described passage by described outlet opening, the part of the line that extends from described passage is by towards the described body part side direction of described bobbin and inwardly guiding, and when described bobbin rotates with respect to described housing, the line of cut of clamping certain-length.

19. trimmer head according to claim 18, the inner at least inwardly convergent of wherein said passage.

20. trimmer head according to claim 18, the cross section of the described at least outside of wherein said passage is a hexagon, and wherein, each described line receiver comprises also that in abutting connection with the line spigot surface of the described outer end of described passage described line spigot surface is used for inwardly guiding from the part of the line of described passage extension towards the described body part of described bobbin.

21. trimmer head according to claim 20, wherein said spigot surface comprises in abutting connection with the described outer end of described passage and the first that extends laterally from described outer end, and in abutting connection with described first and from described first side direction and the second portion that extends internally.

22. trimmer head according to claim 18, wherein said reciprocator comprises being operatively connected between described bobbin and the described housing, and be included in the isolated projection of a plurality of equal angles on described bobbin or the described housing, with be formed on described housing or the described bobbin to receive corresponding a plurality of holes of described projection, each described hole limits front wall section and rear wall section, described front wall section has the axial length longer than described rear wall section, one spring member pushes described projection in the described hole, thereby described trimmer head makes the described front wall section of described projection against described hole along the rotation of described first direction, and make described bobbin along the corresponding rotation of described first direction, and the curve slope of corresponding a plurality of inclinations, each described inclined-plane extends to the rear surface in another described hole from the position near a described hole the arc inclined path, like this, when described bobbin along described first direction during with respect to the rotation of described housing, described projection is crossed the described rear wall section in described hole repeatedly, inclined ramp along adjacency, and under the effect of the power of described spring member, enter in another hole, thereby make described bobbin move back and forth along described common axis with respect to described housing.

23. trimmer head according to claim 18, thereby wherein said trimmer head is to be suitable for colliding the type that the predetermined length line is realized supplying with in ground, and described trimmer head further comprises perpendicular alignmnet, overhead cam that shape is similar and rotation is staggered and following cam, described be connected to cam-operatedly described housing with therewith the rotation, each described cam limits a plurality of cam faces thereon, and cam follower member, described cam pack operatively is connected to described bobbin to rotate therewith and to limit a plurality of cam abutment surface, described cam abutment surface be suitable in response to described trimmer head to the bump on ground and with predetermined increment of rotation selectively with described cam, thereby in described first direction rotation, described bobbin is vertically moved in described housing at described trimmer head and described bobbin, between described bobbin and described housing, produce rotation relatively thus, thereby outwards supply the line of predetermined length by the described outlet opening in the described housing, and wherein, at least one cam and described cam follower member in the described cam limit a slidingsurface, this slidingsurface and each described cam face and described cam abutment surface in abutting connection with and on angle, stagger, thereby when being wrapped in described line on the described bobbin, allow described bobbin to rotate along described first direction, and make described bobbin move back and forth with respect to described housing with respect to described housing.

24. trimmer head according to claim 18, wherein said cross section are oval, thereby limit long axis of pitch, hyphen to axis with perpendicular to the linear center axis of described long axis and described minor axis, are used for the line of cut of the described length of clamping.

25. be provided with the surface imperfection thing in the described passage in the trimmer head according to claim 18, wherein said receiver, be used for the line of cut of the described length of clamping.

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