CN219582725U - Torque spanner - Google Patents

Abstract

The utility model provides a torque wrench which comprises a handle, a force limiting assembly and a clamping head, wherein the force limiting assembly comprises a fixed cam, a movable cam and an elastic piece, the fixed cam is rotationally connected with the handle, and a first cam surface is arranged on one end surface of the fixed cam; the movable cam is connected to the handle in a sliding way, the movable cam can rotate along with the handle, a second cam surface matched with the first cam surface is arranged on the end surface of the movable cam facing the fixed cam, the central shaft of the movable cam is mutually overlapped with the central shaft of the fixed cam, and the sliding direction of the movable cam is parallel to the central shaft of the fixed cam; opposite ends of the elastic piece are respectively propped against the end face of the movable cam, which is opposite to the fixed cam, and the handle, and the expansion and contraction direction of the elastic piece is parallel to the sliding direction of the movable cam; the clamping head is positioned outside the handle and connected with the fixed cam so as to rotate along with the fixed cam, and is provided with at least one bayonet for clamping a workpiece. The torque wrench limits the torque output by the chuck through the force limiting assembly in the screwing process, so that the workpiece is prevented from being damaged due to overlarge torque.

Description

Torque spanner

Technical Field

The utility model relates to a wrench, in particular to a torque wrench.

Background

In dental treatment, the tips of ultrasonic bone knives, ultrasonic tooth cleaners, ultrasonic wave oscillation washers and other devices are connected to handles of corresponding devices through threads, and wrench positions are usually arranged at the rear parts of the tips, so that the tips can be screwed down conveniently by using tools such as wrenches. In addition, in order to meet the needs of different functions and also to meet the sanitary needs, it is often necessary to use tools such as wrenches to detach the tip from the handle for replacement or sterilization. In the prior art, the force for twisting the working tip needs to be controlled more accurately, and if the torque force is too large, the working tip or the handle is easily damaged, so that the treatment effect on teeth is affected. However, it is difficult to control the torque output by the wrench during use of the wrench in the prior art, and thus it is necessary to provide a torque wrench capable of limiting the magnitude of the torque output.

Disclosure of Invention

In order to solve the above-mentioned technical problems, it is necessary to provide a torque wrench capable of limiting the output torque.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:

the torque wrench comprises a handle, a force limiting assembly and a clamping head, wherein the force limiting assembly comprises a fixed cam, a movable cam and an elastic piece, the fixed cam is rotationally connected with the handle, and one end face of the fixed cam is provided with a first cam surface; the movable cam is connected to the handle in a sliding manner, the movable cam can rotate along with the handle, a second cam surface matched with the first cam surface is arranged on the end surface of the movable cam facing the fixed cam, the central shaft of the movable cam and the central shaft of the fixed cam are mutually overlapped, and the sliding direction of the movable cam is parallel to the central shaft of the fixed cam; opposite ends of the elastic piece are respectively propped against the end face of the movable cam, which is opposite to the fixed cam, and the handle, and the expansion and contraction direction of the elastic piece is parallel to the sliding direction of the movable cam; the clamping head is positioned outside the handle and connected with the fixed cam so as to rotate along with the fixed cam, and at least one bayonet used for clamping a workpiece is arranged on the clamping head.

Further, one end of the handle is provided with an installation cavity, and the fixed cam is rotatably arranged at the installation cavity; the movable cam is slidingly arranged in the mounting cavity, and the elastic piece is accommodated in the mounting cavity.

Further, the fixed cam comprises a cam part and a connecting shaft fixed at the center of the end face of the cam part facing away from the movable cam, the cam part is rotatably arranged in the mounting cavity, and the end face of the cam part facing the movable cam is provided with the first cam surface; the connecting shaft penetrates through the mounting cavity in a rotating mode, and one end, located outside the handle, of the connecting shaft is vertically connected with the clamping head.

Further, the mounting cavity comprises a containing part and a penetrating part which are coaxially arranged and sequentially communicated, and the containing part and the penetrating part are sequentially arranged along the direction close to the clamping head; the movable cam is slidingly arranged in the accommodating part, the cam part is rotationally arranged in the accommodating part, and the connecting shaft rotationally penetrates through the penetrating part.

Further, the aperture of the accommodating portion is larger than the aperture of the penetrating portion so as to form a step portion between the accommodating portion and the penetrating portion, the torque wrench further comprises a first check ring and a second check ring, and the first check ring is sleeved on the connecting shaft and is arranged between the cam portion and the step portion in a cushioning mode; the second check ring is sleeved on the connecting shaft and is arranged between the clamping head and the side face of the handle facing the clamping head in a cushioning manner

Further, the handle comprises a spanner head, an operation handle and a top cover, the installation cavity penetrates through two opposite sides of the spanner head along the central shaft of the movable cam to form an opening, and the connecting shaft penetrates through the opening of the installation cavity facing one side of the clamping head; one end of the operating handle is fixedly connected with the peripheral wall of the spanner head, and the top cover is in threaded connection with the opening of the mounting cavity on the side opposite to the clamping head; one end of the elastic piece, which is far away from the movable cam, is elastically abutted with the top cover.

Further, the end face of the movable cam, which is opposite to the fixed cam, is concavely provided with a first limit groove, the side face of the top cover, which faces the mounting cavity, is concavely provided with a second limit groove, and the opposite ends of the elastic piece respectively extend into the first limit groove and the second limit groove.

Further, the center of the chuck is communicated with a flat shaft hole, one end of the connecting shaft, which is far away from the cam part, is provided with an anti-rotation flat position matched with the flat shaft hole, and the flat shaft hole is in plug-in fit with one end of the connecting shaft, which is far away from the cam part.

Further, a first rotation stopping flat position is arranged on the peripheral wall of the movable cam, a second rotation stopping flat position is arranged on the inner wall of the mounting cavity, and the second rotation stopping flat position is matched with the first rotation stopping flat position so as to prevent the movable cam from rotating relative to the handle.

Further, the bayonet penetrates through the peripheral wall of the chuck to form an inlet and an outlet, the bayonet is provided with two side walls which are respectively arranged on two opposite sides of the inlet and the outlet, each side wall is provided with at least two bayonet sections, the at least two bayonet sections are sequentially arranged along the direction away from the inlet and the outlet, the two bayonet sections corresponding to the two side walls form a pulling opening which is used for being clamped with an external workpiece, and the width of at least two pulling openings in each bayonet is gradually reduced along the direction away from the inlet and the outlet.

Further, the chuck is disc-shaped, the number of the bayonets is a plurality of the bayonets, and the bayonets are arranged at intervals along the circumferential direction of the chuck.

Further, the first cam surface comprises a plurality of first protruding surfaces which are arranged at intervals around the central axis of the fixed cam and protrude towards the movable cam, and a first inner concave surface which is connected with two adjacent first protruding surfaces and is recessed towards the direction far away from the movable cam; the second cam surface comprises a plurality of second protruding surfaces which are arranged around the central shaft of the movable cam at intervals and protrude towards the fixed cam, and second inner concave surfaces which are connected with two adjacent second protruding surfaces and are recessed towards the direction far away from the fixed cam, the second protruding surfaces are matched with the first inner concave surfaces, and the first protruding surfaces are matched with the second inner concave surfaces.

By adopting the technical scheme, the utility model has the following beneficial effects:

above-mentioned torque wrench, limit the torsion of chuck output through limit force subassembly in twisting the in-process for work pieces such as work point can twist under the torsion of predetermineeing, avoid torsion too big destruction work piece.

Drawings

Fig. 1 is a schematic perspective view of a torque wrench according to a preferred embodiment of the utility model.

Fig. 2 is a top view of the torque wrench shown in fig. 1.

Fig. 3 is a cross-sectional view taken along line A-A of fig. 2.

Fig. 4 is an enlarged view of fig. 3 at B.

Fig. 5 is a bottom view of the torque wrench of fig. 1.

Fig. 6 is an exploded view of the torque wrench shown in fig. 1.

Fig. 7 is a view of the torque wrench of fig. 6 in another view.

Fig. 8 is a structural view of a handle and a movable cam in a torque wrench according to a preferred embodiment of the present utility model.

Description of the main reference signs

100. A torque wrench; 10. a handle; 11. a mounting cavity; 111. a housing part; 113. a first mounting portion; 114. a second mounting portion; 115. an insertion portion; 116. a step portion; 117. a second rotation stopping flat position; 12. a spanner head; 13. an operation handle; 14. a top cover; 141. the second limit groove; 20. a force limiting assembly; 21. a fixed cam; 211. a first cam surface; 212. a cam section; 214. a connecting shaft; 215. a first protruding surface; 216. a first concave surface; 217. anti-rotation flat position; 23. a movable cam; 231. a second cam surface; 232. a second protruding surface; 234. a second concave surface; 235. a first rotation stopping flat position; 236. a first limit groove; 25. an elastic member; 30. a chuck; 31. a bayonet; 310. an inlet and an outlet; 311. a sidewall; 312. a bayonet section; 313. pulling the opening; 32. a flat shaft hole; 40. a first retainer ring; 50. and a second check ring.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When a component is considered to be "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1 to 3, a torque wrench 100 according to a preferred embodiment of the present utility model includes a handle 10, a force limiting assembly 20 and a chuck 30, wherein the chuck 30 is connected to the handle 10 through the force limiting assembly 20, and the chuck 30 is provided with at least one bayonet 31 circumferentially spaced apart, and the bayonet 31 is used for being clamped with an end of a working tip (not shown) provided with a wrench position. The chuck 30 can drive the working tip to rotate under the drive of the handle 10, so as to realize the screwing or unscrewing of the working tip.

Referring to fig. 4, in the present embodiment, a mounting cavity 11 is provided at one end of a handle 10, specifically: the handle 10 includes a wrench head 12, an operation grip 13, and a top cover 14, and the mounting cavity 11 penetrates opposite sides of the wrench head 12 in the axial direction of the chuck 30 to form an opening (not shown). In the present embodiment, the mounting chamber 11 includes the housing portion 111 and the insertion portion 115 coaxially provided and sequentially communicating, the housing portion 111 and the insertion portion 115 are sequentially provided in a direction approaching the chuck 30, and the aperture diameters of the housing portion 111 and the insertion portion 115 are sequentially reduced in a direction approaching the chuck 30, so that the stepped portion 116 is formed between the insertion portion 115 and the housing portion 111. In the present embodiment, the housing portion 111 specifically includes a first mounting portion 113 and a second mounting portion 114 that are coaxially disposed and communicate with each other, the second mounting portion 114 is closer to the insertion portion 115 than the first mounting portion 113, the aperture of the second mounting portion 114 is smaller than the aperture of the first mounting portion 113, and the stepped portion 116 is formed between the second mounting portion 114 and the insertion portion 115.

One end of the operation handle 13 is fixedly connected to the outer peripheral wall of the wrench head 12, and in this embodiment, the longitudinal direction of the operation handle 13 is perpendicular to the axial direction of the chuck 30. The top cover 14 is in threaded connection with an opening of the mounting cavity 11 on the side facing away from the chuck 30, in this embodiment, an external thread is provided on an outer peripheral wall of the top cover 14, an internal thread is provided on a hole wall of the opening of the mounting cavity 11 on the side facing away from the chuck 30, and the internal thread is in threaded connection with the external thread of the top cover 14, so that the top cover 14 is detachably mounted at the opening of the mounting cavity 11 on the side facing away from the chuck 30. It will be appreciated that in other embodiments, the top cover 14 may be provided with internal threads as desired, and the wrench head 12 of the handle 10 may be correspondingly provided with external threads that threadably engage the internal threads of the top cover 14.

The force limiting assembly 20 is used for limiting the torque force output by the chuck 30. Referring to fig. 6 and 7, the force limiting assembly 20 includes a fixed cam 21, a movable cam 23 and an elastic member 25, wherein the fixed cam 21 is rotatably connected with the handle 10, in this embodiment, an end surface of the fixed cam 21 is located outside the mounting cavity 11 and is connected with the chuck 30, and an end surface of the fixed cam 21 facing away from the chuck 30 is located inside the mounting cavity 11 and is provided with a first cam surface 211; the movable cam 23 is slidably connected to the handle 10 and is rotatable with the handle 10. In the present embodiment, the movable cam 23 is slidably disposed in the mounting chamber 11, the slidable direction of the movable cam 23 is parallel to the central axis of the fixed cam 21, the end surface of the movable cam 23 facing the fixed cam 21 is provided with a second cam surface 231 engaged with the first cam surface 211, and the central axis of the movable cam 23 and the central axis of the fixed cam 21 overlap; opposite ends of the elastic member 25 respectively abut against the end surface of the movable cam 23 facing away from the fixed cam 21 and the handle 10, and the extending and contracting direction of the elastic member 25 is parallel to the slidable direction of the movable cam 23.

In the present embodiment, the fixed cam 21 includes a cam portion 212 and a connecting shaft 214 fixed to the center of the end surface of the cam portion 212 facing away from the movable cam 23. Specifically, in the present embodiment, one end of the cam portion 212, which is close to the connection shaft 214, is rotatably disposed in the second mounting portion 114 of the housing portion 111, and one end of the cam portion 212, which is far from the connection shaft 214, extends into the first mounting portion 113 of the housing portion 111. The cam portion 212 is provided with the first cam surface 211 on an end surface facing the movable cam 23. In the present embodiment, the first cam surface 211 includes a plurality of first protruding surfaces 215 provided at intervals around the central axis of the fixed cam 21 and protruding toward the movable cam 23, and a first concave surface 216 connecting the adjacent two first protruding surfaces 215 and recessed in a direction away from the movable cam 23. The connecting shaft 214 is rotatably connected to the wrench head 12 and penetrates the opening of the mounting chamber 11 facing the chuck 30, and in this embodiment, the connecting shaft 214 rotatably penetrates the insertion portion 115, and the positioning cam 21 can be positioned by the receiving portion 111 and the insertion portion 115. In the present embodiment, the outer diameter of the connecting shaft 214 is smaller than the outer diameter of the cam portion 212, so that the cam portion 212 can abut against the step portion 116, and further, the fixed cam 21 can be prevented from accidentally falling off from the opening of the mounting chamber 11 on the chuck 30 side by the step portion 116.

The movable cam 23 is slidably connected to the wrench head 12, and in the present embodiment, the movable cam 23 is slidably provided in the first mounting portion 113 of the housing portion 111, and the movable cam 23 can be slidably guided by the housing portion 111. The end surface of the movable cam 23 facing the fixed cam 21 is provided with the second cam surface 231, and in this embodiment, the second cam surface 231 includes a plurality of second protruding surfaces 232 disposed at intervals around the central axis of the movable cam 23 and protruding toward the fixed cam 21, and a second concave surface 234 connecting two adjacent second protruding surfaces 232 and recessed away from the fixed cam 21, wherein the second protruding surfaces 232 are engaged with the first concave surface 216 of the first cam surface 211, and the first protruding surfaces 215 of the first cam surface 211 are engaged with the second concave surfaces 234 of the second cam surface 231. Referring to fig. 8, in the present embodiment, a first rotation stopping flat position 235 is further provided on a peripheral wall of the movable cam 23, a second rotation stopping flat position 117 is provided on an inner wall of the accommodating portion 111 of the mounting cavity 11 of the handle 10 in a protruding manner, in the present embodiment, the second rotation stopping flat position 117 is provided on an inner wall of the first mounting portion 113, and the second rotation stopping flat position 117 cooperates with the first rotation stopping flat position 235 to prevent the movable cam 23 from rotating relative to the handle 10, so that the movable cam 23 can rotate together with the handle 10, and torque transmission is realized through cooperation of the first cam surface 211 and the second cam surface 231; and the sliding of the movable cam 23 relative to the handle 10 is not affected by the cooperation of the second rotation stopping flat position 117 and the first rotation stopping flat position 235. It will be appreciated that in other embodiments, the synchronous rotation of the movable cam 23 and the handle 10 may also be achieved by a spline fit. In the present embodiment, the diameter of the movable cam 23 is larger than the diameter of the wheel body 212 of the fixed cam 21, and the reliability of torque transmission between the movable cam 23 and the fixed cam 21 can be further increased. It will be appreciated that in other embodiments, the diameters of the movable cam 23 and the fixed cam 21 may be the same, and accordingly, the apertures of the first mounting portion 113 and the second mounting portion 114 may be the same, or the diameter of the movable cam 23 may be made smaller than the diameter of the fixed cam 21.

The elastic member 25 is accommodated in the mounting cavity 11 of the wrench head 12, one end of the elastic member 25 abuts against one side of the movable cam 23 facing away from the fixed cam 21, and one end of the elastic member 25 facing away from the movable cam 23 abuts against the top cover 14 elastically. In the present embodiment, the elastic member 25 is a spring, and the direction in which the elastic member 25 expands and contracts is parallel to the slidable direction of the movable cam 23. In order to position the elastic member 25 for telescopic movement, in this embodiment, the end surface of the movable cam 23 facing away from the fixed cam 21 is further concavely provided with a first limiting groove 236, and the side surface of the top cover 14 facing the mounting cavity 11 is concavely provided with a second limiting groove 141, and two opposite ends of the elastic member 25 respectively extend into the first limiting groove 236 and the second limiting groove 141.

The torque wrench 100 further includes a first retainer ring 40 and a second retainer ring 50, where the first retainer ring 40 is sleeved on the connecting shaft 214 and is arranged between the cam portion 212 and the step portion 116 in a cushioning manner; the second retainer ring 50 is sleeved on the connecting shaft 214 and is arranged between the chuck 30 and the side surface of the handle 10 facing the chuck 30 in a cushioning manner. By providing the first retainer ring 40 and the second retainer ring 50, foreign matters can be prevented from entering the installation cavity 11 to affect torque transmission between the movable cam 23 and the fixed cam 21.

Referring to fig. 5, the chuck 30 is vertically connected to one end of the connecting shaft 214 outside the mounting cavity 11, in this embodiment, the chuck 30 is disc-shaped, the axis of the chuck 30 coincides with the central axis of the fixed cam 21, the center of the chuck 30 is penetrated and provided with a flat shaft hole 32, one end of the connecting shaft 214 away from the cam portion 212 is provided with an anti-rotation flat 217 adapted to the flat shaft hole 32, and the flat shaft hole 32 is in plug-in fit with one end of the connecting shaft 214 away from the cam portion 212, so that the chuck 30 can rotate together with the fixed cam 21.

In the present embodiment, a plurality of bayonets 31 are provided at the edge of the chuck 30, and the plurality of bayonets 31 are provided at intervals along the circumferential direction of the chuck 30. The bayonet 31 penetrates through the peripheral wall of the chuck 30 to form an inlet and outlet 310, the bayonet 31 is provided with two side walls 311 respectively arranged at two opposite sides of the inlet and outlet 310, each side wall 311 is provided with at least two bayonet sections 312, at least two bayonet sections 312 are sequentially arranged along the direction away from the inlet and outlet 310, the corresponding two bayonet sections 312 on the two side walls 311 of each bayonet 31 form a wrenching opening 313 for being clamped with an external workpiece such as a working tip, and the width of at least two wrenching openings 313 in each bayonet 31 (namely, the vertical distance between the two side walls 311 surrounding the wrenching opening 313) is gradually reduced along the direction away from the corresponding inlet and outlet 310.

In use, the bayonet 31 at the front end of the chuck 30 (i.e. the bayonet 31 at the end far away from the handle 10) is sleeved at the end of the working tip provided with the wrench position, and the working tip is clamped by the wrench opening 313 with proper width. The operating handle 10 rotates, the handle 10 rotates to drive the movable cam 23 to rotate together, and when the movable cam 23 rotates, the fixed cam 21 and the clamping head 30 connected with the fixed cam 21 are driven to rotate together by the friction force between the first cam surface 211 and the second cam surface 231, so that the effect of screwing or unscrewing the working tip is achieved. The friction force between the first cam surface 211 and the second cam surface 231 has a component force pushing the movable cam 23 along the axial direction of the chuck 30 towards one side of the elastic member 25, when the torsion force is smaller than a set value, the component force is smaller than the elastic force of the elastic member 25, the elastic force of the elastic member 25 enables the movable cam 23 to be meshed with the fixed cam 21, namely, the second protruding surface 232 is in plug-in fit with the first concave surface 216 of the first cam surface 211, the first protruding surface 215 of the first cam surface 211 is in plug-in fit with the second concave surface 234 of the second cam surface 231, and then the movable cam 23 drives the fixed cam 21 and the chuck 30 connected with the fixed cam 21 to rotate together with the handle 10; when the torque force is greater than the set value, the component force is greater than the elastic force of the elastic member 25, and the component force pushes the movable cam 23 to slide in a direction away from the fixed cam 21 and compress the elastic member 25, so that the friction force between the first cam surface 211 and the second cam surface 231 is insufficient to drive the fixed cam 21 to rotate, and the movable cam 23 slides relative to the fixed cam 21 during rotation, so that the power transmission between the fixed cam 21 and the movable cam 23 is disconnected, and the force limiting effect is achieved. In addition, when in use, the position of the top cover 14 can be adjusted by rotating the top cover 14 to change the compression degree of the elastic piece 25 in the initial state, so as to adjust the set value of the torsion limiting force.

The torque wrench 100 limits the torque output by the chuck 30 through the force limiting assembly 20 during screwing, so that workpieces such as a working tip can be screwed under the preset torque, and the workpieces such as the working tip are prevented from being damaged due to overlarge torque.

The wrench for disassembling and assembling the working tip in the prior art is used for fixing the size of the bayonet 31 matched with the working tip, and the wrench can only be used for unscrewing or screwing the working tip with one specification wrench position, so that when the working tips with different specification wrench positions need to be replaced on the handle 10, a plurality of wrenches need to be prepared for operation, the operation is inconvenient, and the working efficiency is affected. The torque wrench 100 has the advantages that the bayonet 31 on the chuck 30 is provided with the plurality of pulling ports 313 with different widths, the plurality of pulling ports 313 with different widths can adapt to the screwing and unscrewing of the working tips of the wrench positions with different specifications, and the torque wrench is free from preparing a plurality of wrenches to replace the working tips during working, is convenient to operate, and is beneficial to improving the working efficiency.

In the torque wrench of the embodiment, the chuck 30 is disc-shaped, and a plurality of bayonets 31 are arranged at intervals along the circumferential direction of the chuck 30, so that an operator can conveniently clamp the working tip by adopting the bayonets 31 at proper positions in the process of screwing the working tip, and the torque wrench is convenient to use; and the disc-shaped chuck 30 is more convenient to manufacture.

The torque wrench 100, the handle 10 includes the top cover 14 in threaded connection, the elastic member 25 is only in contact with the top cover 14 and the movable cam 23, when the torque wrench 100 needs to be maintained, the top cover 14 can be detached from the wrench head 12, and then the elastic member 25, the movable cam 23 and the handle 10 are taken out, so that the elastic member 25 can be replaced or maintained conveniently. The top cover 14 is disposed on a side of the handle 10 facing away from the chuck 30, so as to more conveniently adjust the compression degree of the elastic member 25 in the initial state.

In the above-mentioned torque wrench, the opposite ends of the elastic member 25 are respectively disposed in the first limit groove 236 of the top cover 14 and the second limit groove 141 of the movable cam 23, so that the elastic member 25 can be guided to stretch and retract, and the resetting accuracy of the elastic member 25 can be improved.

When the torque wrench is assembled, the fixed cam 21, the movable cam 23 and the elastic piece 25 are sequentially arranged in the mounting cavity 11, and then the top cover 14 is connected with threads, so that the assembly is convenient. After the fixed cam 21 is installed, the cam part 212 of the fixed cam 21 is supported on the step part 116, and the fixed cam 21 can be prevented from moving randomly along the axial direction by the action of the step part 116 and the clamping head 30, so that the fixed cam 21 is prevented from falling off the handle 10; the top cover 14 can also protect the force limiting assembly 20 from external impurities affecting the operation of the force limiting assembly 20.

It will be appreciated that the structure of the resilient member 25 is not limited to the spring of the present embodiment, and that a resilient pad or other elastomer may be used.

It is understood that the shape and structure of the handle 10 are not limited to the present embodiment, and may be provided in other shapes or structures as needed, for example, the operation handle 13 may be omitted, and the movable cam 23 may be rotated by rotating the wrench head 12.

It will be appreciated that the torque wrench 100 of the present embodiment is not limited to twisting with a tip, but may be used for twisting of other workpieces.

It is understood that the connection mode of the chuck 30 and the fixed cam 21 is not limited to the present embodiment, and for example, the chuck 30 and one end of the fixed cam 21 may be fixedly connected by welding or the like.

It will be appreciated that the structure of the fixed cam 21 is not limited to this example, and for example, in other embodiments, the fixed cam 21 may include only the cam portion 212, and one end of the connecting shaft 214 may be connected to the chuck 30 vertically, and at this time, the other end of the connecting shaft 214 is fixedly connected to the cam portion 212 of the fixed cam 21.

It is to be understood that the shape of the chuck 30 is not limited to the disk-like shape of the present embodiment, but may be other shapes, for example, a polygonal plate shape, etc., and the number of the bayonets 31 may be set to one as needed.

It is understood that the shapes of the first cam surface 211 and the second cam surface 231 are not limited to the embodiment, and may be other shapes as required, as long as the chuck 30 can be driven to rotate by the cooperation of the first cam surface 211 and the second cam surface 231, and when the torque force is too large, the movable cam 23 can be pushed to push the movable cam 23 against the fixed cam 21 by the first cam surface 211.

It will be appreciated that only one width of the trigger 313 may be provided in the bayonet 31, or that the width of the trigger 313 may be different in a plurality of bayonets 31, as desired.

The foregoing description is directed to the preferred embodiments of the present utility model, but the embodiments are not intended to limit the scope of the utility model, and all equivalent changes or modifications made under the technical spirit of the present utility model should be construed to fall within the scope of the present utility model.

Claims (10)

1. The torque wrench is characterized by comprising a handle, a force limiting assembly and a clamping head, wherein the force limiting assembly comprises a fixed cam, a movable cam and an elastic piece, the fixed cam is rotationally connected with the handle, and a first cam surface is arranged on one end surface of the fixed cam; the movable cam is connected to the handle in a sliding manner, the movable cam can rotate along with the handle, a second cam surface matched with the first cam surface is arranged on the end surface of the movable cam facing the fixed cam, the central shaft of the movable cam and the central shaft of the fixed cam are mutually overlapped, and the sliding direction of the movable cam is parallel to the central shaft of the fixed cam; opposite ends of the elastic piece are respectively propped against the end face of the movable cam, which is opposite to the fixed cam, and the handle, and the expansion and contraction direction of the elastic piece is parallel to the sliding direction of the movable cam; the clamping head is positioned outside the handle and connected with the fixed cam so as to rotate along with the fixed cam, and at least one bayonet used for clamping a workpiece is arranged on the clamping head.

2. The torque wrench of claim 1, wherein one end of the handle is provided with a mounting cavity, and the fixed cam is rotatably mounted at the mounting cavity; the movable cam is slidingly arranged in the mounting cavity, and the elastic piece is accommodated in the mounting cavity.

3. The torque wrench of claim 2, wherein the fixed cam includes a cam portion and a connecting shaft fixed to a center of an end surface of the cam portion facing away from the movable cam, the cam portion being rotatably provided in the mounting chamber, the end surface of the cam portion facing the movable cam being provided with the first cam surface; the connecting shaft penetrates through the mounting cavity in a rotating mode, and one end, located outside the handle, of the connecting shaft is vertically connected with the clamping head.

4. The torque wrench as claimed in claim 3, wherein the mounting cavity includes a receiving portion and an insertion portion coaxially disposed and sequentially connected, the receiving portion and the insertion portion being sequentially disposed in a direction approaching the chuck; the movable cam is slidingly arranged in the accommodating part, the cam part is rotationally arranged in the accommodating part, and the connecting shaft rotationally penetrates through the penetrating part.

5. The torque wrench as claimed in claim 3, wherein said handle includes a wrench head, a handle and a top cover, said mounting cavity penetrating opposite sides of said wrench head along a central axis of said movable cam to form an opening, said connecting shaft penetrating said opening of said mounting cavity on a side facing said chuck; one end of the operating handle is fixedly connected with the peripheral wall of the spanner head, and the top cover is in threaded connection with the opening of the mounting cavity on the side opposite to the clamping head; one end of the elastic piece, which is far away from the movable cam, is elastically abutted with the top cover.

6. The torque wrench of claim 5, wherein a first limit groove is concavely formed in an end surface of the movable cam facing away from the fixed cam, a second limit groove is concavely formed in a side surface of the top cover facing the mounting cavity, and opposite ends of the elastic member extend into the first limit groove and the second limit groove respectively.

7. The torque wrench as claimed in claim 3, wherein a flat shaft hole is formed through the center of the chuck, an anti-rotation flat position adapted to the flat shaft hole is formed on one end of the connecting shaft away from the cam portion, and the flat shaft hole is in plug-in fit with one end of the connecting shaft away from the cam portion.

8. The torque wrench of claim 2, wherein a first rotation stop feature is provided on a peripheral wall of the movable cam, and a second rotation stop feature is provided on an inner wall of the mounting cavity, the second rotation stop feature cooperating with the first rotation stop feature to prevent rotation of the movable cam relative to the handle.

9. The torque wrench of any one of claims 1-8, wherein the bayonet extends through a peripheral wall of the chuck to form an access opening, the bayonet has two side walls disposed on opposite sides of the access opening, each side wall is provided with at least two bayonet sections, the at least two bayonet sections are disposed in sequence along a direction away from the access opening, two bayonet sections corresponding to the two side walls form a pulling opening for clamping an external workpiece, and a width of at least two of the pulling openings in each bayonet is gradually reduced along a direction away from the access opening.

10. The torque wrench of any one of claims 1-8, wherein the first cam surface includes a plurality of first protruding surfaces disposed at intervals around a central axis of the fixed cam and protruding toward the movable cam, and a first concave surface connecting two adjacent first protruding surfaces and recessed away from the movable cam; the second cam surface comprises a plurality of second protruding surfaces which are arranged around the central shaft of the movable cam at intervals and protrude towards the fixed cam, and second inner concave surfaces which are connected with two adjacent second protruding surfaces and are recessed towards the direction far away from the fixed cam, the second protruding surfaces are matched with the first inner concave surfaces, and the first protruding surfaces are matched with the second inner concave surfaces.