HK40070000A - Dual pawl ratchet mechanism - Google Patents

Description

Ratchet mechanism with double pawls

Technical Field

The present invention relates generally to ratcheting tools, and more particularly to a ratcheting tool having a dual-pawl ratcheting mechanism.

Background

Many dual pawl ratchet mechanisms are known and used today. Typically, these mechanisms are incorporated into hand tools, such as ratchet wrenches and/or screwdrivers and the like, such that there is a drive portion that can engage a workpiece (e.g., a bolt head). A first drive direction (e.g., clockwise) may be selected for the dual pawl ratchet mechanism such that when the tool is engaged with a workpiece, torque is provided in a clockwise direction with the tool and loosening or loosening is provided when the tool is rotated in a second direction (e.g., counterclockwise). A second drive direction (e.g., counterclockwise) may be selected for the dual pawl ratchet mechanism such that when the tool is engaged with a workpiece, torque is provided in the counterclockwise direction with the tool and loosening or loosening is provided when the tool is rotated in a first direction (e.g., clockwise).

The selection of the drive direction for the drive section depends on which of the two pawls is engaged with the ratchet wheel. The mechanism generally relies on a manually actuatable portion (commonly referred to as a reversing lever) to effect engagement of one pawl with the ratchet and disengagement of a second pawl from the ratchet, see U.S. patent 8,499,666. Other known mechanisms use pawl carriers to effect engagement and disengagement of the pawls, see U.S. patent 2,978,081. The mechanism described in us patent 2,978,081 uses a wire to hold the pawl on the pawl carrier. However, fitting the wire to the pawl carrier requires additional parts and manufacturing time and complexity.

Disclosure of Invention

The present invention broadly relates to a hand tool, such as a ratchet wrench, including a ratchet mechanism for selectively engaging either of a first pawl and a second pawl with a ratchet to select either of a first drive direction and a second drive direction (e.g., clockwise and counterclockwise). The pawls include projections that matingly engage recesses in the pawl carrier to selectively provide controlled movement of one of the pawls to an engaged position (in which the pawl engages the teeth of the ratchet wheel) while the other pawl is disposed in a disengaged position (in which the pawl disengages the teeth of the ratchet wheel). The present invention has fewer parts and is simpler to manufacture and substantially uninterrupted pawl-to-gear tooth engagement than current designs.

In one embodiment, the invention broadly comprises a tool. The tool comprises: the tool includes a head having a cavity, a ratchet rotatably disposed in the cavity and having a drive portion and a tooth portion, a pawl carrier pivotally disposed in the cavity and including a groove, wherein the drive portion projects outwardly from the cavity and is adapted to transmit torque to a workpiece, and first and second pawls adapted to selectively engage the tooth portion of the ratchet for selecting either of first and second drive directions of the ratchet. Each of the first and second pawls includes a protrusion adapted to engage the recess such that one of the pawls is engaged with the tooth by pushing the pawl toward the ratchet and the other pawl is disengaged from the tooth by pulling the pawl away from the ratchet.

In another embodiment, the invention broadly comprises a ratchet mechanism comprising a pawl carrier having a recess and being pivotable to cause selection of one of first and second drive directions and a first pawl and a second pawl adapted to selectively engage with a tooth of a ratchet for selecting either of the first and second drive directions. Each of the first and second pawls includes a protrusion adapted to engage the recess such that one pawl is engaged with the tooth by pushing the pawl toward the ratchet and the other pawl is disengaged from the tooth by pulling the pawl away from the ratchet.

Drawings

For the purposes of promoting an understanding of the subject matter sought to be protected, there are shown in the drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

FIG. 1 is an exploded perspective view of an exemplary tool in a disassembled state according to an embodiment of the present invention.

Fig. 2 is a side plan view of a head of an exemplary tool according to an embodiment of the present invention.

Fig. 3 is a front view of the head of fig. 2 with the cover plate removed to view the internal components and a first rotational drive direction selected.

FIG. 4 is a front view of the head of FIG. 2 with the cover plate removed to view the internal components and a second rotational drive direction selected.

Fig. 5 is a cross-sectional view of the head of fig. 2 taken along line 5-5 of fig. 2.

FIG. 6 is a perspective view of a pawl carrier and pawl according to an embodiment of the present invention.

FIG. 7 is an exploded perspective view of another exemplary tool in a disassembled state, according to another embodiment of the present invention.

Fig. 8 is a front view of the head of the tool of fig. 7 in an assembled state with the cover plate removed to view the internal components and a first rotational drive direction selected.

Fig. 9 is a front view of the head of the tool of fig. 7 in an assembled state with the cover plate removed to view the internal components and a second rotational drive direction selected.

FIG. 10 is a perspective view of a pawl carrier and pawl according to another embodiment of the present invention.

FIG. 11 is an exploded perspective view of the pawl carrier and pawl in a disassembled state in accordance with another embodiment of the present invention.

Fig. 12 is another exploded perspective view of the pawl carrier and pawl of fig. 11 in a disassembled state.

Detailed Description

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail embodiments of the invention (including the preferred embodiments), with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to any one or more of the embodiments illustrated herein. As used herein, the term "present invention" is not intended to limit the scope of the claimed invention, but is used merely for explanatory purposes to discuss exemplary embodiments of the invention.

The present invention broadly comprises a tool, such as a ratchet wrench. The ratchet wrench includes a ratchet mechanism for selectively engaging a ratchet in a first drive direction and a second drive direction. The ratchet mechanism includes a first pawl, a second pawl, and a pawl carrier. Each pawl includes a projection and the pawl carrier includes a recess, preferably two recesses, wherein the projections of the pawls are adapted to engage the recesses to selectively move the first pawl to an engaged position (wherein the first pawl engages the ratchet gear) and the second pawl to a disengaged position (wherein the second pawl is disengaged from the ratchet gear). The invention has fewer parts and is simpler to manufacture and provides substantially uninterrupted engagement of the pawl with the ratchet teeth as compared to prior designs.

Referring to fig. 1-6, an exemplary tool 100, such as a dual pawl ratchet wrench, is depicted having a head portion 102 and a handle portion 104. The head 102 includes a cavity 106 for receiving a component of the tool 100, the tool 100 for providing torque to a workpiece (not shown), such as a socket and/or fastener.

The head 102 includes a first detent 108 and a second detent 110 disposed in the cavity 106. The first pawl 108 and the second pawl 110 are selectively engageable with a ratchet wheel 112, the ratchet wheel 112 being operatively engageable with a workpiece in a known manner. When the first pawl 108 is engaged with the ratchet wheel 112 (as shown in FIG. 3), torque drive is permitted as the head 102 rotates in a first rotational drive direction and disengagement occurs as the head 102 rotates in a second rotational drive direction opposite the first rotational drive direction. Conversely, when the second pawl 110 is engaged with the ratchet wheel 112 (as shown in fig. 4), the first pawl 108 disengages the ratchet wheel 112 and allows torque drive as the head 102 rotates in the second rotational drive direction and disengagement occurs as the head 102 rotates in the first rotational drive direction.

The cavity 106 includes portions for receiving and retaining components of the tool 100, respectively. The ratchet wheel 112 is received in a large generally circular first portion of the cavity 106, referred to herein as a drive cavity portion 114. The ratchet wheel 112 has a generally circular body portion 116, said body portion 116 having a circumferential tooth portion 118, and a drive portion 120 projecting from the body portion 116, the drive portion 120 being, for example, a drive lug such as a square. The teeth 118 selectively engage pawl teeth 122 formed on each of the pawls 108, 110 to selectively engage the pawls 108, 110 to provide torque drive via the drive portion 120 in either of the first and second rotational drive directions.

A cover plate 124 is secured to the head 102 to enclose the components of the tool 100 in the cavity 106 in a well known manner. In one embodiment, the cover plate 124 is retained to the head 102 with fasteners 126, such as, for example, screws, rivets, or the like. The cover plate 124 includes an opening 128, such as a circular aperture, through which the drive portion 120 protrudes for operative engagement with a workpiece. Opening 128 also defines a bearing surface for drive portion 120 to retain and position ratchet 112.

The first and second pawls 108, 110 are disposed in a second portion of the cavity 106, referred to herein as a pawl cavity portion 130. The drive cavity portion 114 and the pawl cavity portion 130 overlap or communicate to allow the first pawl 108 and the second pawl 110 to be selectively moved into and out of engagement with the tooth portion 118 of the ratchet wheel 112.

An actuator 132 is provided, the actuator 132 for selectively engaging and disengaging the first pawl 108 and the second pawl 110 from the ratchet wheel 112. In one embodiment, the actuator 132 is disposed in the pawl cavity portion 130. An actuator 132 extends through the head 102, with a stem 134 of the actuator 132 located outside of the head 102 and adapted to be manually operated to select a drive direction of the tool. A seal (not shown) is disposed circumferentially around the stem 134 to inhibit or prevent contaminants or liquids from entering the cavity 106. In one embodiment, the actuator 132 is assembled with the head 102 by inserting the stem 134 into the pawl cavity portion 130 from a first side of the head 102 and by extending the stem 134 through an opening in the head 102 to a second side of the head 102, which improves the ability to prevent the ingress of contaminants with a seal. The actuator 132 is sized to avoid passing completely through the opening, so the actuator 132 can only be installed in one orientation.

The actuator 132 is pivotally coupled to the pawl carrier 136 such that the pawl carrier 136 rotates in unison with the actuator 132 to selectively position one of the pawls 108, 110 into engagement with the ratchet gear to select a torque drive direction. The pawl carrier 136 includes a first recess 138 and a second recess 140. Each pawl 108, 110 includes a surface 142 opposite the pawl teeth, the surface 142 being correspondingly shaped to generally correspond to the first and second recesses 138, 140. In one embodiment, the surface 142 is rounded/curved, and the first and second recesses 138, 140 have a concave or convex surface that is substantially similar to the rounded/curved surface 142 of each pawl 108, 110.

The pawl carrier also includes grooves, preferably first and second grooves 144a and 144b disposed adjacent the first and second recesses 138 and 140. In one embodiment, the grooves 144a, 144b are formed along arcuate paths to generally correspond to the concave or convex shape of the first and second recesses 138, 140. The first pawl 108 and the second pawl 110 each include a projection 146, the projection 146 adapted to slidably engage the grooves 144a, 144b, respectively. For example, the projection 146 of the first pawl 108 engages the first recess 144a and the projection 146 of the second pawl 110 engages the second recess 144 b. While two separate recesses 144a, 144b are shown, the present invention is not so limited and a single recess adapted to selectively engage the protrusions 146 of the respective first and second pawls 108, 110 may be used.

Referring to fig. 3, when the pawl carrier 136 is moved to the first position by the actuator 132 to select the first rotational drive direction, the first recess 144a engages the projection 146 of the first pawl 108 to urge the first pawl 108 into engagement with the ratchet gear 112. Meanwhile, the second recess 144b is engaged with the protrusion 146 of the second pawl 110 to disengage the second pawl 110 from the ratchet gear 112. Thus, when the head 102 is moved in the first rotational drive direction, the pawl teeth 122 of the first pawl 108 remain engaged with the tooth portion 118 of the ratchet gear 112. Conversely, referring to fig. 4, when the pawl carrier 136 is moved by the actuator 132 to the second position to select the second rotational drive direction, the second recess 144b engages the projection 146 of the second pawl 110 to urge the second pawl 110 into engagement with the ratchet gear 112. At the same time, the first recess 144a engages the projection 146 of the first pawl 108 to disengage the first pawl 108 from the ratchet gear 112. Thus, when the head 102 is moved in the second rotational drive direction, the pawl teeth 122 of the second pawl 110 engage the tooth portion 118 of the ratchet gear 112.

The tool 100 is preferably designed to provide a recognized tactile sensation to the user when the actuator 132 is in place for selecting one of the torque drive directions. To this end, a ball and stop arrangement may be provided, as is common in devices of this type. More specifically, the head 102 may include a bore 148 with a biasing member 150, such as, for example, a spring, ball, or pin 152, inserted in the bore 148. The ball 152 is retained in the bore 148 by the pawl carrier 136. Thus, as the actuator 132 rotates, the ball 152 contacts and moves along the outer surface of the pawl carrier 136. More specifically, the outer surface of the pawl carrier 136 includes a pair of stops 154 disposed thereon to engage the balls 152 when the select actuator 132 for the first and second torque drive directions is disposed in position.

Referring to fig. 7-10, an exemplary tool 200, such as a dual pawl ratchet wrench, is depicted having a head portion 202 and a handle portion 204, according to another embodiment. The tool 200 is generally similar to the tool 100 described above, except for the ball and detent structure described below.

Similar to the tool 100 described above, the tool 200 is preferably designed to provide a recognized tactile sensation to the user when the actuator 232 is in place for selecting one of the torque drive directions. To this end, a ball and stop arrangement is provided, as is common in this type of device. In this embodiment, the pawl carrier 236 has a bore 248 in which a biasing member 250, such as, for example, a spring, ball or pin 252 is inserted into the bore 248. The ball 252 contacts an inner surface 256 of the cavity 206 and is retained in the bore 248 by the inner surface 256. Thus, as the actuator 232 rotates, the ball 252 contacts an inner surface 256 of the cavity 206 and moves along the inner surface 256. More specifically, the inner surface 256 of the cavity 206 includes a pair of stops adapted to engage the balls 252 when the actuator 232 is disposed in position for selecting the first and second torque drive directions.

Referring to fig. 11 and 12, a pawl carrier 336 and pawls 308, 310 in accordance with another embodiment of the present invention are shown. The pawl carrier 336 and pawls 308, 310 are substantially similar to the pawl carrier 136 and pawls 108, 110 described above except for the location of the first and second recesses 344a, 344b, and the pawls 308, 310 are substantially identical, as described below.

Similar to the pawl carrier 136 described above, the pawl carrier 336 includes first and second grooves 344a, 344b disposed adjacent the first and second recesses 338, 340. In this embodiment, the first groove 344a is disposed on a first side 356 of the pawl carrier 336 and the second groove 344b is disposed on a second side 358 of the pawl carrier 336. In one embodiment, the grooves 344a, 344b are formed along arcuate paths to generally correspond to the concave or convex shape of the first and second recesses 338, 340. The first pawl 308 and the second pawl 310 each include a projection 346, the projection 346 adapted to slidably engage the grooves 344a, 344b, respectively. For example, in a similar manner as described above, the projection 346 of the first pawl 308 engages the first groove 344a and the projection of the second pawl 310 engages the second groove 344 b. In this embodiment, the first pawl 308 and the second pawl 310 are substantially identical.

In general, the design of the tool 100, 200 serves to retain and position each component within the head 102, 202, either by the cover plate 124, 224 or by cooperation with one of the other components, thereby minimizing the use of, for example, screws or other fasteners, as well as other manufacturing steps commonly used to assemble a dual pawl ratchet wrench.

As used herein, the term "coupled" may refer to any direct or indirect physical, electrical, magnetic, or other connection between two components. The term "coupled" is not limited to a fixed and direct coupling between two entities.

The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. The actual scope of protection sought is intended to be defined by the claims appended hereto, when viewed in their proper perspective based on the prior art.

Claims (21)

1. A tool, comprising:

a head having a cavity;

a ratchet rotatably disposed in the cavity and having a drive portion and a tooth portion, wherein the drive portion protrudes outwardly from the cavity and is adapted to transmit torque to a workpiece;

a pawl carrier rotatably disposed in the cavity and including a groove; and

a first pawl and a second pawl adapted to selectively engage the tooth portion for selecting one of a first drive direction and a second drive direction, wherein each of the first pawl and the second pawl includes a protrusion adapted to engage the groove when the pawl carrier rotates to disengage one of the first pawl and the second pawl from the tooth portion and engage the other of the first pawl and the second pawl with the tooth portion.

2. The tool of claim 1, wherein the first drive direction is selected when the first pawl is engaged with the tooth portion and the second pawl is disengaged from the tooth portion; the second drive direction is selected when the first pawl is disengaged from the tooth portion and the second pawl is engaged with the tooth portion.

3. The tool of claim 1, further comprising: a reversing lever coupled with the pawl carrier, wherein the reversing lever is movable between and to first and second lever positions corresponding to the first and second drive directions, respectively.

4. The tool of claim 1, wherein the pawl carrier includes a first recess and a second recess.

5. The tool of claim 1, further comprising a biasing member and a ball, wherein the head includes a bore adapted to receive the biasing member and the ball.

6. The tool of claim 5, wherein the pawl carrier includes a detent positioned thereon to correspond to a proper position of the ball for selection of one of the first and second drive directions, wherein the ball is biased into engagement with the corresponding detent by a spring when one of the first and second drive directions is selected.

7. The tool of claim 1, further comprising: a cover plate attachable to the head for closing the cavity, the cover plate comprising an opening adapted to receive the drive portion projecting outwardly from the cavity.

8. The tool of claim 1, wherein the groove is formed along a generally arcuate path.

9. The tool of claim 1, further comprising: a biasing member and a ball, wherein the pawl carrier includes a bore adapted to receive the biasing member and the ball.

10. The tool of claim 9, wherein the cavity includes a detent formed on an inner surface to correspond to a proper position of the ball for selection of one of the first and second drive directions, wherein the ball is biased into engagement with the corresponding detent by a spring when the one of the first and second drive directions is selected.

11. The tool of claim 1, wherein the groove comprises a first groove and a second groove, and wherein the first groove is disposed on a first side of the pawl carrier and the second groove is disposed on a second side of the pawl carrier.

12. The tool of claim 11, wherein the first pawl and the second pawl are substantially identical.

13. A ratchet mechanism comprising:

a pawl carrier including a groove and rotatable to cause selection of one of a first drive direction and a second drive direction; and

a first pawl and a second pawl adapted to selectively engage a tooth of a ratchet wheel to select one of the first drive direction and the second drive direction, wherein each of the first pawl and the second pawl includes a protrusion adapted to engage the groove when the pawl carrier rotates to disengage one of the first pawl and the second pawl from the tooth and engage the other of the first pawl and the second pawl with the tooth.

14. The ratchet mechanism of claim 13, wherein the first drive direction is selected when the first pawl is engaged with the tooth portion and the second pawl is disengaged from the tooth portion; the second drive direction is selected when the first pawl is disengaged from the tooth portion and the second pawl is engaged with the tooth portion.

15. The ratchet mechanism of claim 13, further comprising a reversing lever coupled with the pawl carrier, wherein the reversing lever is movable between and to first and second lever positions corresponding to the first and second drive directions, respectively.

16. The ratchet mechanism of claim 13, wherein the pawl carrier includes a first recess and a second recess.

17. The ratchet mechanism of claim 13, wherein the pawl carrier includes a detent positioned thereon to correspond to a proper position of a ball for selection of one of the first and second drive directions, wherein the ball is biased into engagement with the corresponding detent by a spring when the one of the first and second drive directions is selected.

18. The ratchet mechanism of claim 13, wherein the pawl carrier includes an aperture adapted to receive a biasing member and a ball.

19. The ratchet mechanism of claim 13, wherein the groove is formed along a generally arcuate path.

20. The ratchet mechanism of claim 13, wherein the groove comprises a first groove and a second groove, and wherein the first groove is disposed on a first side of the pawl carrier and the second groove is disposed on a second side of the pawl carrier.

21. The ratchet mechanism of claim 13, wherein the first pawl and the second pawl are substantially identical.