HK1099607B - Wire stripper which can be automatically adapted to different conductor cross sections - Google Patents

Description

Wire stripper capable of automatically matching different wire cross sections

Technical Field

The invention relates to a stripping pliers which automatically adapts to different wire cross sections and insulation layer thicknesses and has two pairs of pivoting jaws, of which the outer pair is designed as a clamping jaw and can be moved by a first jaw arm and a jaw part having a common pivot point, and the other pair of inner jaws is designed as a shearing jaw, has a shearing blade which cuts into the insulation and has a pull rod which is fastened to the shearing jaw and is moved longitudinally in the pliers body to cause a stripping movement, and is connected to the second jaw arm by means of a lever.

Background

It is known to use various pliers and similar hand tools for removing the insulation of the cable. Adjustable or fixed-adjustment wire strippers provide greater safety for the operator and the cable material than conventional electrician knives. In order to obtain an efficient electrically conductive connection, it must be ensured that the electrical lines (single-core or multi-core) are not damaged during the insulation removal. In this respect, it is important firstly that the covering on the cable end and also the insulation of the individual conductors can be cleaned and removed in the contact area according to length. The main advantage of conventional automatic wire strippers is that the insulation can be cut in one operation and then removed from the conductor using the handles of the pliers. However, previous adaptations to different insulation layers and cable thicknesses have had to be accomplished by manually adjusting pliers or by having a plurality of differently shaped knife edges. There is always a risk of damage to the wires due to handling or adjustment errors.

DE 4420006 a1, for example, describes a forceps for insulation removal of the wire ends, having a pair of outer holding jaws and a pair of inner cutting jaws. The limited fit with the cable cross-section is achieved by the resistance of the holding jaws on the compressed cable sheath. In the case of very small cable diameters, the compression is limited by additional stops. In this respect, it must not be possible to adapt to different thicknesses of insulating material. There is therefore a risk of shearing too shallow if the insulating material is hard or too deep if the insulating material is soft. As a result, the cable to be decoated is uneven or the wires are damaged.

EP 0645861 a2 describes a stripping pliers with two pairs of pivotally mounted jaws, the outer pair of jaws being formed as clamping jaws and the other pair of inner jaws being formed as shearing jaws with a shearing blade which cuts into the insulation. By means of an eccentric wheel, different wire cross sections and insulation thicknesses can be matched. The operator can change the position of the lower cutting jaw and the associated cutting knife by twisting the eccentric.

DE 4420050C 1 discloses a stripping pliers, in which at least one cutting jaw has a bundle of lamellae arranged side by side and displaceable perpendicularly to the longitudinal direction of the jaw, which have cutting edges that are pressed into the insulation of the conductor when the pliers are closed. The lamellae are supported by clamping arms with V-shaped notches. Narrowing or widening through the gap is matched with different lead cross sections. The insulation removal for different conductor cross sections therefore requires the provision of clamping arms with different indentations, which must be selected by the operator and inserted into the stripping pliers.

Disclosure of Invention

The object of the invention is therefore to improve a stripping pliers in such a way that the cutting depth of the cutting blade can be automatically adapted to different conductor cross sections, insulation thicknesses and insulation materials in a simple manner.

This object is achieved by the wire stripper according to the invention in that the at least one sliding key is mounted in a recess in the first jaw arm or jaw part which is matched to the shape of the sliding key, wherein the first sliding key surface facing the shearing jaw is planar and the second sliding key surface lying in the recess is designed in such a way that the distance between the two sliding key surfaces decreases from the central region of the sliding key at least towards one of the two sliding key ends. When the wire stripper is opened, the sliding key moves in the longitudinal direction and is matched with the sliding key in a position perpendicular to the longitudinal direction, so that the automatic cutting depth adjustment of the cutting knife is realized.

By using such a feather key, the cutting jaw can be adjusted in a simple manner to match the cutting depth in the insulation. Depending on whether corresponding feather keys are present in the first jaw arm, in the jaw part or in both parts, one or both cutting jaws can be adjusted. By means of a corresponding shaping of the second sliding-key surface, which is supported in the first jaw arm or in the gap of the jaw part, a basic adaptation to the required cutting depths of different insulating materials can also be achieved on the part of the manufacturer.

The use of the stripping pliers according to the invention ensures for the first time an automatic adaptation of the cutting depth of the cutting blade of the cutting jaw, which enables the pliers to be used for about 0.5mm²-10mm²Cable cross-section within the range.

According to a particularly advantageous embodiment of the stripping pliers, a first sliding key is mounted in a recess in the first pliers leg and a second sliding key, which is formed in the same manner, is mounted in a recess in the jaw part. In this respect, a circular arc shape has proved to be particularly advantageous for the second sliding key surface of the sliding key. The distance between the two sliding key surfaces is thus reduced from the central region of the sliding key to the ends of the sliding key. In this embodiment, the two cutting jaws can be adjusted in depth, thereby always ensuring a uniform and clean cut on both sides. In a variant embodiment, however, the second sliding surface can also have another profile, for example, inclined to the plane of the first sliding surface, so that a sliding key with a wedge shape on only one side is formed.

In another embodiment, depending on the purpose, the face of the cutting jaw adjacent to the feather key has first and second projections. The first projection is used for the shearing jaw to produce point contact on the first sliding key surface. By having only such contact between the shear jaw and the feather key surface, rather than full-face contact, friction of the shear jaw against the feather key surface can be minimized and thus ensure that the feather key does not move abruptly.

According to a further advantageous embodiment, the clamping jaws have in each case one projecting clamping tooth, preferably at the end of the clamping jaws that comes into contact with the cutting jaws. The raised clamping teeth and the shearing blades have a shearing bevel which is formed as a mirror image of one side. When the pliers are closed, the raised clamping teeth cut slightly into the cable, thereby achieving additional positioning of the insulation remaining on the cable.

In a further embodiment according to the object, the first feather key surfaces are brought into a slightly inclined position relative to one another by the shape of the second feather key surfaces during the longitudinal displacement of the feather key. This causes the shear jaws to open slightly as they are directed forward during stripping of the shear jaws. It is possible to compensate for unevenness on the sheathed cable to be removed and prevent damage to the core wire.

It is also advantageous if the cutting knife is releasably fastened to the cutting jaw. Preferably, the cutting knife is screwed onto the end face of the cutting jaw close to the clamping jaw. Whereby they can be easily replaced in case of wear or replaced by other shearing knives adapted to the purpose. The use of profiled edges is also conceivable if relatively hard insulating materials, such as teflon for example, have to be handled.

Preferably, the clamping jaws are releasably fixed in the receiving jaw. In the event of wear, the clamping jaws can therefore also be replaced here simply. Furthermore, the clamping jaws can be vertically adjusted, so that the press-in depth can be adapted.

Drawings

Further advantages, details and further developments arise from the following description of a preferred embodiment with the aid of the drawing. Wherein:

figure 1 shows a general view of a wire stripper according to the invention with open jaws;

figure 2 shows a general view of a wire stripper with closed jaws according to the invention;

FIG. 3 shows a schematic diagram of the longitudinal movement of the feather key;

FIG. 4 shows a detail of the jaws;

FIG. 5 shows a detail of a clamping jaw with a material receiving jaw;

fig. 6 shows a detailed view of the feather key with position assurance.

Detailed Description

Fig. 1 shows a general view of a stripping pliers according to the invention with open jaws. The wire stripper comprises a first jaw arm 1 and a jaw part 3 having a common pivot point 5. The second gripper arm 7, which is connected to the first gripper arm 1 via the pivot axis 8, acts via the lever 9 with the roller 11 on the jaw part 3 in such a way that the jaws are likewise closed during the closing of the gripper arms by the user.

Located in the cutout of the first pliers leg 1 is a first sliding key 13 with a first sliding key surface 15 facing the jaw opening and a second sliding key surface 17 resting against the cutout. The first feather key 13 is connected to the jaw member 3 by a first link 19. The first pin 21 is used to secure the first link 19 within the jaw member 3.

The second feather key 23 is supported in a notch in the jaw member 3. It has a first splined surface 25 turned towards the jaw opening and a second splined surface 27 resting against the notch. The second feather key 23 is connected to the first jawarm 1 via a second link 29. The second pin 31 is used to fixedly engage the second link 29 with the first jawarm 1.

The first splined surface 15, 25 turned towards the jaw opening is plane. The second sliding-key surfaces 17, 27, which lie in contact with the recesses, are preferably designed in such a way that the distance between the first and second sliding-key surfaces 15, 17 or 25, 27, starting from the central region of the sliding key 13, 23, narrows uniformly towards the two sliding-key ends. A circular arc shape proves particularly advantageous. The recesses for supporting the slide keys 13, 23 are adapted to the shape of the slide keys 13, 23 and likewise have a circular-arc-shaped sliding surface, which corresponds to the second slide key surface.

The stripping pliers are also provided with two pairs of pivoting jaws. The outer first pair of jaws is formed as a clamping jaw 33 and can be moved by means of the first gripper arm 1 and the jaw part 3. The other pair of inner jaws is formed as a cutting jaw 41, with a cutting knife 37 releasably fixed to the cutting jaw and cutting into the insulation. The shear jaw 41 is fixed on a pull rod 43 which is moved in the longitudinal direction of the jaw body to cause the stripping movement and is connected with the second jaw arm 7 through a lever 9.

Also between the first and second jawarms 1, 7 is a wire cutter 45 for transversely cutting the cable to be stripped. The cutting edges of the pliers are also closed when the pliers legs are closed, wherein the cutting can be easily performed by the lever action produced on the pivot shaft 8.

The de-insulating layer process is performed as follows. A cable (not shown) is threaded between the clamping jaws 33 so that the desired area of insulation to be removed is behind the shearing blade 37. The movable gripper arm 7 is then moved toward the first gripper arm 1 when the gripper is gripped. At the same time, the jaw part 3 is also pivoted about the pivot point 5 by means of the lever 9, which is connected at one end to the second gripper arm 7 and at the other end is articulated to the jaw part 3 by means of the roller 11, whereby the jaws are closed and the two clamping jaws 33 are firmly engaged with the cable sheath. At the same time, the cutting jaw 41 is also moved into the cutting position, as will be described in more detail below.

The clamping jaws 33 preferably each have a raised clamping tooth 47 (see fig. 4). Such raised gripping teeth 47 and shear knives 37 have single mirror-image shear slopes. The raised clamping teeth 47 cut into the cable sheath when the clamping jaws 33 are closed and thus serve for additional positioning of the insulation remaining on the cable. The resistance of the clamping jaws 33 on the clamped cable sheath prevents a further closing movement.

The adjustment of the cutting depth is achieved in that, during further clamping of the pliers and the pivoting of the jaw part 3 about the pivot point 5, the first feather key 13 is easily pulled out of the jaw end by the pull rod 43 connected to the jaw part 3. At the same time, the first feather key 13 is moved by the amount by which the difference is generated by the distances a and B between the front end of the feather key and the stopper leading edge in the notch shown in fig. 1 and 2. By this movement, the cutting jaw 41 is closed by the feed amount C and at the same time the angular position of the first feather key 13 is changed from the position E to the position D (see fig. 3).

In synchronism with this, the second feather key 23, which is fixedly connected to the first gripper arm 1 by means of the connecting rod 29, is deflected by the jaw part 3, so that the second feather key 23 moves relative to the jaw part 3 in the same direction as the first feather key 13. A feed movement of the cutting jaw 41 perpendicular to the longitudinal movement by the amount C and a positional correction of the second feather key 23 from E to D therefore also take place here. By selecting the back arc radius R of the feather key 13, 23 shown in fig. 3, the feed C and the position correction can be optimized for different purposes.

During the further change, the insulation is thus stripped off the conductor, i.e. by the movement of the lever 9 towards the tension spring 49, the cutting jaws 37, 39 are pulled into the direction of the center of the pliers by the tension rod 43 connected to the lever 9.

There is a point-like contact of the shearing jaw 41 on the first spline surfaces 15, 25 during stripping. This contact is achieved by a first projection 51 on the face of the shear jaw 41 adjacent the first splined surface 15, 25. Furthermore, a second projection 53 is provided on the same cutting jaw face. The second projection 53 faces the center of the moving cutting jaw 41. For this purpose, the tension rod 43 has a long hole 55 therein, so that the two shearing jaws 41 can be positioned uniformly on the clamping jaw 33 by means of the tension spring 49.

In a preferred embodiment, the shape of the second feather key surface 17, 27 causes a slight tilting of the first feather key surface 15, 25 during longitudinal displacement of the feather key 13, 23. As the cutting jaws 41 are guided in an antegrade manner, the cutting jaws 41 and the cutting knives 37 screwed thereon are thus opened to a minimum during the stripping.

FIG. 4 shows a detail of the jaws. The clamping jaws 33 each have a raised clamping tooth 47. The clamping jaw can be formed as a plug receptacle as shown in fig. 5 or as two parallel planar columns. On the spigot or flat column is a respective thickened portion 57 which ensures clamping in the receiving jaw 59. The clamping jaw 33 can be vertically adjusted by means of a compression screw 61. This adjustment is typically made at the manufacturer.

As can be seen from fig. 6, a securing pin 63 is used to secure the position of the feather keys 13, 23. The sliding keys 13, 23 are therefore additionally protected against undesirable changes in position under any conceivable load conditions.

Reference numerals

1 first tong arm

3 jaw part

5 turning point

7 second forceps arm

9 Lever

11 roller

13 first sliding key

15 first feather key surface of first feather key

17 second feather key surface of first feather key

19 first link

21 first pin

23 second feather key

25 first feather key surface of second feather key

27 second feather key surface of second feather key

29 second connecting rod

31 second pin

33 clamping jaw

37 shearing knife

41 shearing jaw

43 draw bar

45 wire pliers

47 raised gripping teeth

49 tension spring

51 first projection

53 second projection

Slot 55

57 thickened part

59 material receiving jaw

61 compression screw

63 safety pin

Claims (9)

1. Stripping pliers for automatically adapting to different wire cross sections and insulation thicknesses, having two pairs of pivotably mounted jaws, of which the outer pair is formed as a clamping jaw (33) and can be moved by a first pliers limb (1) having a common pivot point (5) and a pliers limb (3), and the other pair of inner jaws is formed as a shearing jaw (41), having a shearing blade (37) which cuts into the insulation and a tension rod (43) which is fastened to the shearing jaw (41) and is longitudinally movable in the pliers body to cause a stripping movement, the tension rod being coupled to the second pliers limb (7) via a lever (9), characterized in that a first sliding key (13) is mounted in a recess in the first pliers limb (1) which is matched to the shape of the first sliding key (13) and a second sliding key (23) is mounted in a recess in the pliers limb (3) which is matched to the shape of the second sliding key (23), the first sliding key surfaces (15, 25) of the turning cutting jaw (41) are plane surfaces, and the second sliding key surfaces (17, 27) which are closely attached in the gap are formed in such a way that the distance between the two sliding key surfaces is reduced from the central area of the first sliding key (13) and the second sliding key (23) to at least one of the two sliding key ends, and when the wire stripper is clamped, the first sliding key (13) and the second sliding key (23) move in the longitudinal direction and simultaneously the first sliding key (13) and the second sliding key (23) are matched in position perpendicular to the longitudinal direction, so that the cutting depth of the cutting jaw (41) and the cutting knife (37) fixed on the cutting jaw is adjusted.

2. Wire stripper according to claim 1, wherein the second sliding key surfaces (17, 27) of the first sliding key (13) and the second sliding key (23) are rounded.

3. Stripping pliers according to claim 2, wherein the first sliding key (13) is connected to the jaw part (3) via a first connecting rod (19) and the second sliding key (23) is connected to the first pliers leg (1) via a second connecting rod (29), and the jaw part (3) pivots during the clamping of the pliers, while the first connecting rod (19) moves in relation to this in such a way that the first sliding key (13) is moved in the longitudinal direction, wherein in synchronism with this the second connecting rod (29) fixes the second sliding key (23), and the jaw part (3) is deflected by the second sliding key (23) during the movement around it and thus produces a corresponding engagement of the second sliding key (23) by this relative movement.

4. Stripping pliers according to one of claims 1 to 3, wherein the cutting jaw (41) has, on its side adjacent to the first feather key (13) and the second feather key (23), a first projection (51) for the cutting jaw (41) to make point contact on the first feather key side (15, 25) and a second projection (53) opposite the center of the moving cutting jaw (41).

5. Stripping pliers according to claim 1, wherein the clamping jaws (33) each have a raised clamping tooth (47), and the raised clamping teeth (47) and the cutting blade (37) have a single-sided mirror-image cutting bevel.

6. Wire stripper according to claim 1, wherein the second splined surface (17, 27) is shaped to cause a slightly inclined position of the first splined surface (15, 25) when the splines (13, 23) are moved longitudinally, which position causes a slight opening of the cutting blade (37) when the cutting jaw (41) is guided forward during stripping.

7. Stripping pliers according to claim 1, wherein the cutting blade (37) is releasably fastened to the cutting jaw holder (41).

8. Stripping pliers according to claim 1, wherein the clamping jaw (33) is releasably fixed in the receiving jaw (59), and the clamping jaw (33) is adjustable in distance relative to the clamping surface.

9. Wire stripper as claimed in claim 1, wherein a wire cutter (45) is arranged between the first (1) and the second (7) jaw arm.