PAWL CONTROL DEVICE FOR RATCHET WRENCH

Abstract

A ratchet wrench includes a handle and a head through which a hole is defined. A recess is defined in the inner periphery of the hole. A driving member is rotatably received in the hole. A pawl and a positioning member are respectively located in two respective ends of the recess. A spring is connected between the pawl and the positioning member. The pawl has a slot defined in a lateral side thereof so as to be connected to one end of the spring. The positioning member is a resilient member and has an engaging portion and a curved portion. An opening is defined between the engaging portion and the curved portion. The other end of the spring is engaged with the opening. The spring linearly biased between the pawl and the positioning member to engage the pawl with the driving member.

Claims

1. A ratchet wrench comprising: a handle and a head, the head having a hole defined there through, a recess defined in an inner periphery of the hole and located between the hole and the handle; a driving member rotatably received in the hole and having first teeth defined in an outside thereof, and a pawl and a positioning member respectively located in two respective ends of the recess, a spring connected between the pawl and the positioning member, the pawl having second teeth defined in a front side thereof, the second teeth facing the first teeth, a slot defined in a lateral side of the pawl, a first end of the spring engaged with the slot, the positioning member being a resilient member and made by a stainless steel plate which is bent to include having an engaging portion and a curved portion, the engaging portion resiliently in contact with the first teeth of the driving member, an opening defined between the engaging portion and the curved portion, the engaging portion has a bent end, a second end of the spring engaged with the opening and connected to the bent end, the curved portion having a protrusion extending from an inside thereof, the protrusion inserted into the second end of the spring, the spring linearly biased between the pawl and the positioning member, the pawl being pushed by the linearly operational spring to move along the recess, the second teeth of the pawl being engaged with the first teeth of the driving member.

2. The ratchet wrench as claimed in claim 1, wherein the recess has a curved inner periphery, the pawl has a curved face which is connected between the front side having the first teeth and the lateral side having the slot of the pawl, the curved face of the pawl moves along the curved inner periphery of the recess.

3. The ratchet wrench as claimed in claim 1, wherein the slot is a dove-tailed slot with which the first end of the spring is engaged.

4. The ratchet wrench as claimed in claim 2, wherein the slot is a dove-tailed slot with which the first end of the spring is engaged.

5. (canceled)

6. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is an exploded view of the ratchet wrench of the present invention;

[0014] FIG. 2 is a perspective view to show the ratchet wrench of the present invention;

[0015] FIG. 3 is a cross sectional view, taken along line III-III in FIG. 2;

[0016] FIG. 4 shows that the ratchet wrench of the present invention is rotated clockwise;

[0017] FIG. 5 shows that the ratchet wrench of the present invention is rotated counter clockwise, and

[0018] FIG. 6 is an enlarged view to show the relationship between the pawl and the driving member when the ratchet wrench of the present invention is rotated counter clockwise.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] Referring to FIGS. 1 to 3, the ratchet wrench 1 of the present invention comprises a handle 11 and a head 12, wherein the head 12 has a hole 13 defined therethrough. A recess 14 is defined in the inner periphery of the hole 13 and located between the hole 13 and the handle 11. The recess 14 has a curved inner periphery.

[0020] A driving member 15 is rotatably received in the hole 13 and has first teeth 151 defined in the outside thereof. The driving member 15 has a mounting hole defined centrally therethrough so as to be mounted to an object.

[0021] A pawl 2 and a positioning member 3 are respectively located in two respective ends of the recess 14, and a spring 4 is connected between the pawl 2 and the positioning member 3. The pawl 2 is a substantially wedge-shaped member and includes a front side, a lateral side and a rear side which is connected between the front side and the lateral side. Multiple second teeth 21 are defined in the front side thereof, and the second teeth 21 face the first teeth 151. A slot 22 is defined in the lateral side of the pawl 2 and the slot 22 is a dove-tailed slot. The first end of the spring 4 is engaged with the slot 22 and cannot be disengaged from the slot 22 in the direction perpendicular to the lateral side of the pawl 2. The positioning member 3 is a stainless steel plate which is bent to include an engaging portion 31 and a curved portion 32 which extends integrally from the engaging portion 31. An opening 33 is defined between the engaging portion 31 and the curved portion 32. The positioning member 3 is a resilient member. The second end of the spring 4 is engaged with the opening 33. Specifically, the engaging portion 31 has a bent end 311 which is connected to the second end of the spring 4. The curved portion 32 has a protrusion 321 extending from the inside thereof, and the protrusion 321 is inserted into the second end of the spring 4. The slot 22 of the pawl 2 and the opening 33 of the positioning member 3 are located along a straight line. In other words, the spring 4 is linearly biased between the pawl 2 and the positioning member 3. The pawl 2 has a curved face 23 which is connected between the front side having the first teeth 21 and the lateral side having the slot 22 of the pawl 2. The curved face 23 of the pawl 2 moves along the curved inner periphery of the recess 14. The pawl 3 is pushed by the linearly operational spring 4 to move along the recess 14 so that the second teeth 21 of the pawl 2 are engaged with the first teeth 151 of the driving member 15 when the ratchet wrench 1 is rotated clockwise as shown in FIG. 4.

[0022] As shown in FIG. 5, when the ratchet wrench 1 is rotated counter clockwise, the inner periphery of the recess 14 tends to remove away from the pawl 2 so that the second teeth 21 of the pawl 2 are disengaged from the first teeth 151 of the driving member 15. Under this status, the ratchet wrench 1 is freely rotated relative to the object. The pawl 2 and the positioning member 3 do not have any restriction means to restrict their position except for the inner periphery of the recess 14, so that the spring 4 is linearly operated to move the pawl 2 along the inner periphery of the recess 14.

[0023] As shown in FIG. 6, when the ratchet wrench 1 is rotated counter clockwise, the positioning member 3 is moved by the inner periphery of the recess 14, the engaging portion 31 of the positioning member 3 is slightly deformed as shown by the phantom line, and the first teeth 151 of the driving member 15 move along the surface of the engaging portion 31, this also reduces wearing to the first teeth 151.

[0024] The advantages of the present invention are that the pawl 2 and the positioning member 3 do not have any restriction means to restrict their position except for the inner periphery of the recess 14, so that the spring 4 is linearly operated to move the pawl 2 along the inner periphery of the recess 14 to precisely engage with the driving member 15.

[0025] The positioning member 3 is a stainless steel plate which is bent to include the engaging portion 31 and the curved portion 32, so that the positioning member 3 has a certain level of flexibility which allows the engaging portion 31 of the positioning member 3 to be slightly deformed so that when the first teeth 151 of the driving member 15 move along the surface of the engaging portion 31, the wearing to the first teeth 151 is reduced.

[0026] While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.