Ratchet wrench

Abstract

A ratchet wrench includes a wrench body, a ratchet gear, a pawl and a switch assembly. The pawl has a central tooth, multiple first sub teeth and multiple second sub teeth in a concave surface thereof. Each of the first sub teeth and the second sub teeth has an inner side face abutting against opposing tooth face of the ratchet gear and an outer side face spaced apart from opposing tooth face of the ratchet gear. The first sub teeth and the second sub teeth are located symmetrical relative to the central tooth. The center of the concave surface of the pawl and the center of the ratchet gear are located on a common line that passes through the center of the central tooth of the pawl. The switch assembly is movably disposed in the head of the ratchet wrench for driving the pawl to engage with the ratchet gear.

Claims

1. A ratchet wrench comprising: a wrench body having a head at one end thereof, the head having a cavity, a first compartment and a second compartment therein, the first compartment intercommunicating the cavity and the second compartment; a ratchet gear rotatably disposed in the cavity of the wrench body and defining a plurality of ratchet teeth, each of the ratchet teeth defining two opposite tooth faces; a pawl movably received in the first compartment of the wrench body, the pawl defining a central tooth, a plurality of first sub teeth and a plurality of second sub teeth in a concave surface on a front side thereof, the first sub teeth and the second sub teeth disposed at opposite sides of the central tooth, a curvature of the concave surface of the pawl being defined such that the first sub teeth and the second sub teeth are located symmetrical relative to the central tooth, a center of the concave surface of the pawl and a center of the ratchet gear being located on a common line that passes through a center of the central tooth of the pawl, the central tooth being fully engaged with two adjacent ratchet teeth of the ratchet gear and two side faces of the central tooth respectively abutting against opposing tooth faces of the two adjacent ratchet teeth, each of the first and second sub teeth defining an inner side face closer to the central tooth, and an outer side face opposite to the inner side face, the inner side faces of the first and second sub teeth being larger than the outer side faces of the first and second sub teeth respectively, when the central tooth is fully engaged with two adjacent ratchet teeth of the ratchet gear, the inner side face abuts against an opposing tooth face of the ratchet gear, and the outer side face and opposing tooth face of the ratchet gear are spaced apart by a distance; and a switch assembly movably disposed in the second compartment of the wrench body for driving the pawl to engage with the ratchet gear.

2. The ratchet wrench of claim 1, wherein the pawl defines at a top thereof a concave surface of a curvature corresponding to the ratchet gear and a recess corresponding to the switch assembly.

3. The ratchet wrench of claim 1, wherein tips of the central tooth, the first sub teeth and the second sub teeth of the pawl are rounded.

4. The ratchet wrench of claim 1, wherein tips of the ratchet teeth are flat.

5. The ratchet wrench of claim 2, wherein the switch assembly has a switch lever and an elastic driving member; and the switch lever is operable to have the elastic driving member abut against a wall of the recess of pawl for selectively driving the pawl to engage with the ratchet gear and to control an active direction of the ratchet gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an exploded perspective view of a ratchet wrench of the present invention;

(2) FIG. 2 is an enlarged view of the pawl of the ratchet wrench shown in FIG. 1;

(3) FIG. 3 is a perspective view of the ratchet wrench of the present invention;

(4) FIG. 4 is a top view of the ratchet wrench of the present invention, showing the switch assembly being turned to the first position;

(5) FIG. 5 is a partial enlarged view of FIG. 4;

(6) FIG. 6 is a top view of the ratchet wrench of the present invention, showing the switch assembly being turned to the second position;

(7) FIG. 7 is a partial enlarged view of FIG. 6, and

(8) FIG. 8 shows that the center of the concave surface of the pawl and the center of the ratchet gear are located on the same line that passes through the center of the central tooth of the pawl.

DETAILED DESCRIPTION OF THE INVENTION

(9) Referring to FIGS. 1-7, a ratchet wrench in accordance with a preferred embodiment of the present invention comprises a wrench body 1, a ratchet gear 2, a pawl 3 and a switch assembly 4. The wrench body 1 has a head 10 at one end thereof. The head 10 defines a cavity 11, a first compartment 12 and a second compartment 13 therein. The first compartment 12 intercommunicates the cavity 11 and the second compartment 13, as shown in FIG. 1. The ratchet gear 2 is rotatably disposed in the cavity 11 of the wrench body 1 and defines a plurality of ratchet teeth 21. Each of the ratchet teeth 21 has two opposite tooth faces.

(10) The pawl 3 is movable in the first compartment 12 of the wrench body 1 between a firs position (FIGS. 4-5) and a second position (FIGS. 6-7). The pawl 3 defines a central tooth 31, a plurality of first sub teeth 32 and a plurality of second sub teeth 33 in a concave surface thereof which is located at the front side of the pawl 3 and faces the ratchet gear 2. A recess 34 is defined in the rear side of the pawl 3 and located corresponding to the switch assembly 4. The first sub teeth 32 and the second sub teeth 33 are respectively disposed at opposite sides of the central tooth 31. Referring to FIG. 5 and FIG. 7, the central tooth 31 is fully engaged with two adjacent ratchet teeth 21 of the ratchet gear 2 while two side faces of the central tooth 31 are respectively abut against opposing tooth faces of the two adjacent ratchet teeth 21. Specifically, each of the first and second sub teeth 32, 33 defines an inner side face 321, 331 closer to the central tooth 31 and an outer side face 322, 332 opposite to the inner side face 321, 331. The inner side face 321, 331 abuts against opposing tooth face of the ratchet gear 2. Particularly, the outer side face 322, 332 and opposing tooth face of the ratchet gear 2 are spaced apart in a distance 30. Referring to FIGS. 4-7, the switch assembly 4 is movably disposed in the second compartment 13 of the wrench body 1 for driving the pawl 3 to switch between the first position and the second position.

(11) Under this arrangement, the distance 30 is defined between the respective outer side face 322, 332 of each of the first and second sub teeth 32, 33 and the respective opposing tooth face of the ratchet gear 2, as shown in FIG. 5 and FIG. 7. In other words, the first sub teeth 32 and the second sub teeth 33 each engages with the respective ratchet tooth 21 of the ratchet gear 2 by only one side face. Therefore, the ratchet gear 2 could be smoothly rotatable relative to the pawl 3; besides, the pawl 3 could also be smoothly switched between the first position and the second position to prevent each of the first and second sub teeth 32, 33 from being worn easily during the operation.

(12) Referring to FIG. 8, the curvature of the concave surface of the pawl 3 is defined such that the first sub teeth 32 and the second sub teeth 33 are located symmetrical relative to the central tooth 31. Furthermore, the curvature of the concave surface of the pawl 3 and the curvature of the outer periphery of the ratchet gear 2 are the same, which means that the center R1 of the concave surface of the pawl 3 and the center R2 of the ratchet gear 2 are located on a common line that passes through the center of the central tooth 31 of the pawl 3. Accordingly, there is no radial distance as disclosed in above-mentioned analysis regarding to the disclosure of US 2004/0083860 to Arnold et al.

(13) Specifically, the inner side faces 321, 331 of the first and second sub teeth 32, 33 are slightly larger than the outer side faces 322, 332 of the first and second sub teeth 32, 33 respectively, as shown in FIG. 5 or FIG. 7. Furthermore, tips of the central tooth 31, the first sub teeth 32 and the second sub teeth 33 of the pawl 3 are rounded slightly. Tips of the ratchet teeth 21 are flat. As shown in FIG. 1, the switch assembly 4 has a switch lever 41 and an elastic driving member 42. The switch lever 41 is operable to have the elastic driving member 42 abut against a wall of the recess 34 of pawl 3 for selectively pushing the pawl 3 to engage with the ratchet gear 2 and to control an active direction of the ratchet gear 2.

(14) Although embodiments of this invention have been fully described with reference to the accompanying drawings, it is to be understood that various modifications can be made by those skilled in the art without departing from the scope of the invention as hereinafter claimed.