CN103707270A

CN103707270A - Handheld tool

Info

Publication number: CN103707270A
Application number: CN201210371015.XA
Authority: CN
Inventors: 杜祥金
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2012-09-28
Filing date: 2012-09-28
Publication date: 2014-04-09

Abstract

A handheld tool comprises a casing, an output shaft, a work head support mechanism and a connecting shaft. The output shaft is provided with an accommodating hole for accommodating a work head. The work head support mechanism is arranged inside the casing and provided with a plurality of parallel accommodating spaces used for supporting the work head, and the work head support mechanism can be adjusted to positions where one of the accommodating spaces axially corresponds to the accommodating hole of the output shaft. The connecting shaft is arranged inside the casing and can move between two positions so as to drive the work head to be in the working position inside the accommodating hole or the accommodating position of the work head support mechanism. The connecting shaft is provided with a supporting surface abutted against the work head, the work head is provided with a fitting surface abutted against the connecting shaft, and at least one of the supporting surface and the fitting surface is a curved surface.

Description

Hand-held tool

Technical Field

The invention relates to a hand-held tool, in particular to a gun drill type power tool capable of realizing storage and quick replacement of a working head.

Background

Among the existing power tools of the gun drill type, electric drills, electric screwdrivers and impact drills are generally included.

When a hand-held tool movably connected with a working head such as a drill bit and a screwdriver bit acts on an operation object, the problem that the working head obviously shakes often occurs. The working head shaking can cause the working quality problems of inaccurate processing position, oblique screw installation, rough edges of screw caps and the like.

The research shows that the factors of working head shaking are mainly as follows: 1. the shape and the manufacturing accuracy of the connecting shaft. 2. The shape and the manufacturing precision of the working head.

Accordingly, the inventors have provided a hand held tool that overcomes the above-mentioned disadvantages, based on an extensive study of the prior art.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a handheld tool with good working head stability.

The technical scheme adopted by the invention for solving the technical problems is as follows: a hand-held tool comprising: a housing; the output shaft is provided with an accommodating hole which is axially arranged and used for accommodating the working head; the working head supporting mechanism is arranged in the shell and is provided with a plurality of accommodating spaces which are arranged in parallel and used for supporting the working heads, and the working head supporting mechanism can be adjusted to a position where one accommodating space axially corresponds to the accommodating hole of the output shaft; the connecting shaft is arranged in the machine shell and can move between two positions to drive the working head to be positioned at a working position in the accommodating hole or at an accommodating position of the working head supporting mechanism; the connecting shaft is provided with a supporting surface capable of being abutted against the working head, the working head is provided with a matching surface capable of being abutted against the connecting shaft, and at least one of the supporting surface and the matching surface is a curved surface.

Preferably, the other of the support surface and the mating surface is planar.

Preferably, the curved surface is a convex curved surface.

Preferably, the supporting surface is a curved surface, and the mating surface is a flat surface.

Preferably, the support surface is a convex curved surface.

Preferably, the accommodating hole is provided with a supporting piece for circumferentially supporting the working head.

Preferably, at least one end of the connecting shaft, which can abut against the working head, is magnetized.

Preferably, the curved surface is provided on the magnet.

Preferably, the hand-held tool further comprises: a motor disposed in the housing and outputting rotational power; and the transmission mechanism is arranged between the motor and the output shaft and can transmit the rotary power output by the motor to the output shaft.

Compared with the prior art, the invention has the beneficial effects that: one of the supporting surface of the connecting shaft and the adapting surface of the working head is a curved surface, and the collinear degree of the connecting shaft and the working head can still be stably contacted within a certain range and cannot shake.

Drawings

FIG. 1 is a cross-sectional view of a preferred power tool of the present invention in an operational state.

Fig. 2 is a partially exploded perspective view of the power tool of fig. 1.

Fig. 3 is a schematic illustration of the first embodiment of the present invention prior to mating.

Fig. 4 is a schematic view of the mating of the first embodiment of the present invention.

Fig. 5 is a schematic view of the mating of the second embodiment of the present invention.

Fig. 6 is a schematic diagram of a third embodiment of the present invention.

Fig. 7 is a schematic view of a fourth embodiment of the present invention.

Wherein,

100 DC electric screwdriver 2 motor 51 accepting hole

1 Chassis 21 gearbox 511 support

11 sliding cover 22 cover plate 52 shaft sleeve

111 guide rail 3 transmission mechanism 6 working head

112 first cam 30 pinion mechanism 60 mating surface

113 second cam 31 planetary gear reduction 7 storage clip

12 guide groove 4 connecting shaft 71 containing bin

13 stopper 40 bearing surface 8 Battery

14 front shell 41 fixed block 9 button switch

141 axial opening 5 output shaft

Detailed Description

The invention provides a handheld tool with good stability of a working head.

In a preferred embodiment of the hand tool of the present invention, a dc powered screwdriver is provided, but the hand tool involved in the present invention should not be limited to include only such a dc powered screwdriver. The hand-held tools can be classified into pneumatic, hydraulic, and electric tools according to the power source. In the case of electric tools, there is a distinction between direct current and alternating current. And the tool can be classified into screwdriver, drilling tool, milling tool and the like according to the difference of the working head or the difference of the processing object. In order to briefly explain the core content of the present invention, the present invention is specifically described by taking a dc power screwdriver as an example.

Referring to fig. 1 and 2, the dc electric screwdriver 100 includes a casing 1, a motor 2, a battery 8, a transmission mechanism 3 coupled to the motor 2, a connecting shaft 4 coupled to the transmission mechanism 3, an output shaft 5 coupled to the connecting shaft 4 and driving a working head 6 to move, and a working head supporting mechanism for storing the working head 6. According to the above configuration of the dc electric screwdriver 100, the dc electric screwdriver 100 can be divided into a motor section D in which the motor 2 is provided, a transmission section C in which the transmission mechanism 3 is provided, a storage section B in which the storage clip 7 is provided, and an output section a in which the output shaft 5 is provided, in this order from the rear to the front (with the right side of the drawing as the rear).

The casing 1 is used for accommodating components in the dc electric screwdriver 100 and for an operator to hold and operate. The casing 1 is assembled by folding two half-shell-shaped casings which are symmetrical left and right through screws (not shown). The housing 1 has a horizontal portion and a handle portion arranged at an obtuse angle K to the horizontal portion. The preferred angle K of the present invention is between 100 and 130 degrees so that the grip handle is comfortable to handle. The horizontal portion of the housing 1 houses the transmission mechanism 3 and the motor 2. The handle portion of the housing 1 houses a battery 8 and is provided with a push button switch 9. The button switch 9, the battery 8 and the motor 2 are electrically connected to control the state of the dc electric screwdriver 100. A battery 8 is secured to the rear of the handle portion. A push button switch 9 is arranged at the front of the handle portion.

The motor 2 is a direct current motor having a motor shaft extending forward from the motor housing 1. The motor 2 is connected to a battery 8 to generate a driving force. In alternative embodiments, the solution providing the driving force may be a pneumatic pump, a hydraulic pump, an internal combustion engine, or the like.

The battery 8 is a lithium ion battery. It should be noted that the lithium ion battery is a generic term of a rechargeable battery in which a negative electrode material is lithium element, and may be constructed in many systems, such as a "lithium manganese" battery, a "lithium iron" battery, and the like, depending on a positive electrode material. In the present embodiment, the battery 8 is a lithium ion battery having a rated voltage of 3.6V (volts). Of course, the battery 8 may also be of a nickel cadmium, nickel hydrogen, or the like, of a type well known to those skilled in the art.

The transmission mechanism 3 is used for transmitting power. The transmission mechanism 3 includes a planetary gear reduction mechanism 31 and a pinion mechanism 30 driven by the motor 2 from back to front (back on the right side of the drawing). The planetary gear reduction mechanism 31 and the pinion mechanism 30 are housed in a gear case 21 fixed in the housing 1. The planetary gear reduction mechanism 31 is coupled to the pinion mechanism 30, and the pinion mechanism 30 is connected to the connecting shaft 4 to transmit the rotational motion of the motor 2 to the connecting shaft 4. The gear box 21 is fixed in the housing 1 at the front of the motor 2. A cover plate 22 is arranged between the gear box 21 and the working head supporting mechanism to separate the transmission mechanism 3 from the working head supporting mechanism, namely, the transmission mechanism 3 and the working head supporting mechanism are mutually independent.

One end of the connecting shaft 4 is connected to the pinion mechanism 30, and the other end is connected to the housing 1. Referring to fig. 1 to 3 and 6, the connecting shaft 4 is a hexagonal shaft. A hexagonal hole is provided in the pinion mechanism 30. The connecting shaft 4 passes through the hexagonal hole of the pinion mechanism 30 with clearance fit, and is driven by the pinion mechanism 30.

The storage part B mainly comprises a working head supporting mechanism. The working head supporting mechanism is arranged in the machine shell 1 and is provided with a plurality of parallel accommodating spaces for storing the working heads 6. The working head 6 mainly refers to a cross screwdriver head, a straight screwdriver head and the like which are commonly used by the direct current electric screwdriver. The output shaft 5 is provided with a receiving hole 51 for receiving the working head 6. The working head support mechanism can be adjusted to a position where one of the receiving spaces axially corresponds to the receiving hole 51 of the output shaft 5, so that different working heads 6 can be quickly replaced to tighten or loosen different screws.

In a preferred embodiment of the invention the work head support mechanism is a storage clamp 7 rotatably supported between the cover plate 22 of the gearbox and the output shaft 5. The storage clamp 7 is provided with a plurality of storage bins 71 for storing the working heads 6 uniformly distributed along the circumferential direction, that is, a plurality of storage spaces are arranged in parallel along the rotation axis of the storage clamp 7. The axial correspondence between the storage compartment 71 of the working head 6 and the storage hole 51 of the output shaft 5 is achieved by rotating the storage clip 7.

The working head 6 is replaced by axially moving the connecting shaft 4. The axial displacement of the connecting shaft 4 and the exchange of the working head 6 will now be described.

A sliding cover 11 is slidably connected to the housing 1. The sliding cover 11 can drive the connecting shaft 4 to move axially. The edge of the sliding cover 11 is provided with a guide rail 111, the corresponding casing 1 is provided with a guide groove 12, and the sliding cover 11 is installed in the guide groove 12 through the guide rail 111 and can slide axially relative to the casing 1. Of course, the sliding cover 11 may be provided with a guide groove, and the sliding cover 11 may be moved by providing a guide rail on the housing 1.

A fixing block 41 is axially fixed on the connecting shaft 4, and the sliding cover 11 can drive the connecting shaft 4 to move by connecting with the fixing block 41. The inside of the sliding cover 11 is provided with a first bump 112 and a second bump 113 at an interval along the axial direction of the connecting shaft 4, and the first bump 112 is spaced from the fixed block 41 by a distance S in the axial direction in the operating state of the dc electric screwdriver. When the sliding cover 11 slides backwards, i.e. slides towards the motor 2, after the distance S, the first protrusion 112 abuts against the fixed block 41 axially, so that the sliding cover 11 drives the fixed block 41 and then drives the connecting shaft 4 to move backwards axially. Conversely, the second protrusion 113 drives the connecting shaft 4 to move axially forward. In addition, when the direct current electric screwdriver 100 is operated, the working head 6 needs to be axially pressed against a screw or a workpiece, so that the working head 6 can be acted by a reverse axial force and can generate backward movement of the connecting shaft 4, in the embodiment, the shell 1 is provided with the limiting block 13 which is elastically pressed, and the limiting block 13 can move between two positions which are abutted against and separated from the fixing block 41 so as to limit and allow the axial movement of the connecting shaft 4.

Of course, there are many ways for the sliding cover 11 to drive the connecting shaft 4 to move, for example, an annular groove surrounding the periphery of the connecting shaft 4 may be provided on the connecting shaft 4, and the sliding cover 11 extends into the annular groove through a pin or a wire ring to connect with the connecting shaft 4, so that the rotation of the connecting shaft 4 is not affected, and the sliding cover 11 drives the connecting shaft 4 to move is also not affected.

The connecting shaft 4 is magnetized as a whole or at least at one end abutting against the working head 6. The working head 6 is attracted to the connecting shaft 4. Thus, the axial movement of the connecting shaft 4 drives the working head 6 to move, so that the working head 6 is in a working position in the accommodating hole 51 or in an accommodating position in the working head supporting mechanism. Of course, mounting slots for receiving magnets may also be provided in the connecting shaft 4. At least one magnet is mounted in the mounting slot.

The connecting shaft 4 is operated to place the working head 6 in the working position. The torque when the motor 2 rotates is transmitted to the connecting shaft 4 through the transmission mechanism 3, and the output shaft 5 is matched and connected with the connecting shaft 4 to rotate and drives the working head 6 to rotate. When the working head 6 is replaced, the connecting shaft 4 is operated to make the working head 6 be in the accommodating position in the working head supporting mechanism, namely the accommodating bin 71 of the storage clamp 7. The working head accommodating mechanism is rotated, so that the accommodating space provided with the matched working head 6 is axially corresponding to the accommodating hole 51 of the output shaft 5, namely the accommodating bin 71 is opposite to the accommodating hole 51. The connecting shaft 4 is operated again to move axially to push the working head 6 into the working position, namely the accommodating hole 51 of the output shaft 5.

The output portion a mainly includes an output shaft 5. The receiving hole 51 of the output shaft 5 and the connecting shaft 4 are hexagonal shapes that fit each other. The output shaft 5 is coupled with the connecting shaft 4. The driving force of the motor 2 is transmitted to the output shaft 5 to drive the working head 6 for operation. The cabinet 1 includes a front case 14. The front shell 14 is provided with an axial opening 141. The output shaft 5 is supported within the axial opening 141 of the front housing 14 by a bushing 52. The sleeve 52 provides radial support for the output shaft 5, although radial support of the output shaft 5 may be provided by bearings.

The section of the handle of the working head 6 is regular hexagon, that is, the handle is formed as the torque stress part of the working head 6. The working head 6 is inserted into the output shaft 5 accommodating hole 51 and driven by the output shaft 5.

The connecting shaft 4 has a support surface 40 that can abut against the working head 6. The working head 6 has an engagement surface 60 that can abut against the connecting shaft 4. At least one of the support surface 40 and the mating surface 60 is curved. In one case, one of the support surface 40 and the mating surface 60 is curved and the other is flat. In the second case, both the support surface 40 and the mating surface 60 are curved. These two cases are described separately below.

Referring to fig. 3 to 5, the supporting surface 40 is a convex curved surface, and the mating surface 60 is a flat surface. When the supporting surface 40 is a convex curved surface, the central convex point E on the supporting surface 40 abuts against the planar mating surface 60. The contact position of the central bump with the mating surface 60 is located near the center of the mating surface 60, or the contact region when the mating surface 60 and the supporting surface 40 are abutted is located around the center of the mating surface 60. Thus, even if the connecting shaft 4 and the working head 6 have poor accuracy of alignment within a certain range, a certain point near the central salient point on the supporting surface 40 contacts with the mating surface 60, and because the contact region is arranged around the center of the mating surface 60, the supporting forces of the contact region and the connecting shaft 4 around the contact region to the mating surface 60 are relatively balanced, and no obvious shaking occurs between the two. As shown in fig. 5, the contact position E' of the support surface 40 with the mating surface 60 is offset from the center of the support surface. The supporting surface 40 and the adapting surface 60 are in point contact, and the accommodating hole 51 provides circumferential support for the working head 6, so that the working head 6 can still be prevented from shaking. Of course, it is also possible that the support surface 40 is concavely curved. Referring to fig. 6, the supporting surface 40 is a plane surface, and the mating surface 60 is a convex curved surface.

Referring to fig. 7, the supporting surface 40 is a convex curved surface, and the mating surface 60 is a convex curved surface. When the supporting surface 40 is a convex curved surface, the contact area formed by the supporting surface 40 and the mating surface 60 is a point contact area, the two contact areas are stably abutted, the supporting forces of the contact area and the connecting shaft 4 around the contact area to the mating surface 60 are relatively balanced, and no obvious shaking is generated between the two. Of course, it is also possible that at least one of the supporting surface 40 and the mating surface 60 is concave.

When the magnet is installed at one end of the connecting shaft 4, which can be abutted against the working head 6, the magnet can be provided with a curved surface matched and connected with the working head 6.

The contact area is determined by the angle formed between the working head 6 and the connecting shaft 4, or by the difference in accuracy allowed by the co-linearity of the two. Within the allowable range of precision difference, when the distance between the center of the contact area and the axis of the working head 6 is less than 2 mm, the balance of the supporting force of the connecting shaft 4 to the working head 6 is better. Particularly, the maximum gap between the supporting surface 40 and the adapting surface 60 is less than 1 mm, and the supporting force of the connecting shaft 4 on the working head 6 is uniform when the connecting shaft is extruded and deformed by the working head 6.

The present invention designs at least one of the supporting surface 40 and the mating surface 60 as a curved surface. The shaking of the working head 6 caused by the poor precision generated by the manufacturing and mounting precision when the two are planes is overcome. Wherein, the adapting surface 60 of the working head 6 is planar because the working head is usually a standard component. In order to make the hand-held tool as versatile as possible, the supporting surface 40 of the connecting shaft 4 of the hand-held tool is designed as a curved surface. In particular, the support surface 40 is a convexly curved surface in order to allow the working head 6 to be adjusted to a rest position by means of power. Preferably, in order to maintain the alignment between the working head 6 and the connecting shaft 4, as shown in fig. 6, a support member 511 for circumferentially supporting the working head 6 is provided in the receiving hole 51.

Claims

1. A hand-held tool comprising:

a housing;

the output shaft is provided with an accommodating hole which is axially arranged and used for accommodating the working head;

the working head supporting mechanism is arranged in the shell and is provided with a plurality of accommodating spaces which are arranged in parallel and used for supporting the working heads, and the working head supporting mechanism can be adjusted to a position where one accommodating space axially corresponds to the accommodating hole of the output shaft;

the connecting shaft is arranged in the shell and can move between two positions to drive the working head to be positioned at a working position in the accommodating hole or at an accommodating position of the working head supporting mechanism;

the method is characterized in that: the connecting shaft is provided with a supporting surface capable of being abutted against the working head, the working head is provided with a matching surface capable of being abutted against the connecting shaft, and at least one of the supporting surface and the matching surface is a curved surface.

2. The hand-held tool of claim 1, wherein: the other of the support surface and the mating surface is planar.

3. The hand-held tool of claim 1, wherein: the curved surface is a convex curved surface.

4. The hand-held tool of claim 1, wherein: the supporting surface is a curved surface, and the matching surface is a plane.

5. The hand-held tool of claim 4, wherein: the supporting surface is a convex curved surface.

6. The hand-held tool of claim 1, wherein: the accommodating hole is provided with a supporting piece for circumferentially supporting the working head.

7. The hand-held tool of claim 1, wherein: one end of the connecting shaft, which is abutted against the working head, is magnetized.

8. The hand-held tool of claim 1, wherein: and one end of the connecting shaft, which can be abutted against the working head, is provided with a magnet.

9. The hand-held tool of claim 8, wherein: the curved surface is arranged on the magnet.

10. The hand-held tool of claim 1, wherein: the hand-held tool further comprises:

a motor disposed in the housing and outputting rotational power;

and the transmission mechanism is arranged between the motor and the output shaft and can transmit the rotary power output by the motor to the output shaft.