Ratchet tool comprising pawl with biasing action

Abstract

A ratchet tool is disclosed that includes a pawl having a biasing effect that permits a user to selectively determine the direction in which torque is applied to a workpiece. The rear surface of the pawl creates an instability between the biasing member and the rear surface when the biasing member engages the rear surface at the mid-plane of the pawl. The instability results in a net force that guides the biasing member and the pawl away from the mid-plane. This arrangement ensures that the pawl does not position itself in a central rest position between the sidewalls of the ratchet head.

Description

Technical Field

[0001] The present disclosure generally relates to a pawl for use in a ratchet tool. Ratchet tools include, for example, ratchet wrenches and torque wrenches. Such ratchet tools typically include a reversible drive that is capable of applying torque to a workpiece in a first rotational direction or a second rotational direction to tighten or loosen a fastener. Background Art

[0002] Ratchet tools typically include a cylindrical gear attached to the drive, a pawl for engaging the gear, a switch for controlling the relative orientation of the pawl with respect to the gear, and a biasing member disposed within the switch. Generally, the biasing member engages the rear surface of the pawl to bias the pawl towards the gear. Applying torque to the fastener relies on the mechanical engagement of the pawl and the gear to prevent the gear (and thus the drive) from rotating in the first rotational direction or the second rotational direction.

[0003] Traditional ratchet tools include a pawl having a symmetric rear surface. In these traditional pawl configurations, when the biasing member contacts the symmetric rear surface of the pawl at the midplane of the pawl, the pawl may undesirably position itself in a central rest position at the midplane of the ratchet gear, between the sidewalls of the ratchet assembly cavity. Such a position may be prone to gear slip or failure. In this central rest position, when the biasing member contacts the pawl at the midplane, a net zero force is generated by the symmetric rear surface of the pawl and the biasing force of the biasing member. Thus, it is advantageous to eliminate the possibility of the central rest position and ensure that the pawl is fully biased in a clockwise or counterclockwise position to improve the reliability of the ratchet tool. It is further advantageous to provide a pawl that is operable to generate a net force that guides the pawl away from the midplane when the biasing member contacts the pawl at the midplane. Summary of the Invention

[0004] Disclosed is a ratchet tool including a pawl having a biasing action, as illustrated and described in connection with the figures of the present disclosure and as set forth in the appended claims.

[0005] Specifically, an exemplary ratchet tool is disclosed. The ratchet tool includes a ratchet head that includes a ratchet assembly cavity and a ratchet gear rotatably disposed within the ratchet assembly cavity. The ratchet gear includes a drive member for transmitting torque to a workpiece. The ratchet gear further defines a perimeter and a plurality of ratchet gear teeth disposed about the perimeter. The ratchet tool further includes a pawl operable to selectively engage the ratchet gear. The pawl includes a front surface defining a midpoint of the front surface and a first plurality of pawl teeth disposed on a first side of the midpoint of the front surface. The first plurality of pawl teeth are selectively engageable with the ratchet gear teeth. The front surface further defines a second plurality of pawl teeth disposed on a second side of the midpoint of the front surface. The second plurality of pawl teeth are selectively engageable with the ratchet gear teeth. The pawl is operable to selectively engage either the first plurality of pawl teeth or the second plurality of pawl teeth with the ratchet gear teeth to restrict rotation of the ratchet gear in one of a first rotational direction and a second rotational direction. The pawl further includes a rear surface defining a midpoint of the rear surface and a midplane intersecting the midpoint of the front surface and the midpoint of the rear surface. The rear surface further defines an engagement surface disposed within an engagement plane. The engagement plane is disposed at a selected angle relative to the midplane of the pawl. The ratchet tool further includes a switch disposed through a switch aperture in the ratchet assembly cavity. The switch includes a biasing member operable to engage the rear surface of the pawl such that the biasing member urges the pawl against the ratchet gear.

[0006] In one example, the selected angle of the engagement surface is non-perpendicular. In another example, the engagement surface is inclined relative to the midplane of the pawl. In another example, at the midplane of the pawl and the midplane of the ratchet gear, the engagement surface creates an instability between the biasing member and the pawl such that the pawl is forced in a first rotational direction or a second rotational direction.

[0007] In one example, the engagement surface of the pawl includes a first concave curve, a second concave curve, and a convex curve formed between the first concave curve and the second concave curve. In one example, the convex curve is eccentrically positioned relative to the midplane of the pawl and a tangent to the convex curve forms a non-perpendicular angle relative to the midplane of the pawl. In another example, at the midplane of the pawl and the midplane of the ratchet gear, the convex curve creates an instability between the biasing member and the pawl such that the pawl is forced in a first rotational direction or a second rotational direction.

[0008] In one example, the biasing member includes a spring and a pin. The spring and the pin are at least partially disposed within the switch. In one example, the pin includes a body and a head. In this example, the head includes a non-planar surface.

[0009] An example ratchet tool is also disclosed. The ratchet tool includes a ratchet head. The ratchet head includes a ratchet assembly cavity and a ratchet gear rotatably disposed in the ratchet assembly cavity. The ratchet gear includes a drive member for transmitting torque to a workpiece. The ratchet gear defines a perimeter and a plurality of gear teeth disposed about the perimeter. The ratchet head further includes a pawl operable to selectively engage the ratchet gear. The pawl includes a front surface defining a midpoint of the front surface, the front surface including a first plurality of pawl teeth disposed on a first side of the midpoint of the front surface. The first plurality of pawl teeth are selectively engageable with the ratchet gear teeth. The front surface further includes a second plurality of pawl teeth disposed on a second side of the midpoint of the front surface. The second plurality of pawl teeth are selectively engageable with the ratchet gear teeth. The pawl is operable to selectively engage either the first plurality of pawl teeth or the second plurality of pawl teeth with the ratchet gear teeth to restrict rotation of the ratchet gear in one of a first rotational direction and a second rotational direction. The pawl further includes a rear surface defining a midpoint of the rear surface. The pawl defines a midplane intersecting the midpoint of the front surface and the midpoint of the rear surface. The rear surface further defines an engagement surface disposed in an engagement plane. The ratchet head further includes: a switch disposed to pass through a switch hole in the ratchet assembly cavity; and a biasing member partially disposed within the switch. The biasing member is operable to engage the engagement surface of the pawl such that the biasing member biases the pawl against the ratchet gear. When the biasing member contacts the engagement surface of the pawl, a surface angle that is not perpendicular is formed between a central axis of the member and the engagement surface of the pawl.

[0010] In another example, the engagement surface is inclined relative to the midplane of the pawl. In another example, at the midplane of the pawl and the midplane of the ratchet gear, the engagement surface creates an instability between the biasing member and the pawl such that the pawl is forced in a first rotational direction or a second rotational direction.

[0011] In one example, the engagement surface of the pawl includes a first concave curve, a second concave curve, and a convex curve formed between the first concave curve and the second concave curve. In one example, the convex curve is eccentrically positioned relative to the midplane of the pawl, and a tangent to the convex curve forms an angle that is not perpendicular to the midplane of the pawl. In another example, at the midplane of the pawl and the midplane of the ratchet gear, the convex curve creates an instability between the biasing member and the pawl such that the pawl is forced in a first rotational direction or a second rotational direction.

[0012] Also disclosed is an exemplary pawl for a ratchet tool. The pawl includes a front surface defining a midpoint of the front surface, the front surface including a first plurality of pawl teeth disposed on a first side of the midpoint of the front surface. The first plurality of pawl teeth are selectively engageable with a plurality of ratchet gear teeth. The pawl further includes a second plurality of pawl teeth disposed on a second side of the midpoint of the front surface. The second plurality of pawl teeth are selectively engageable with the ratchet gear teeth. The pawl is operable to selectively engage either the first plurality of pawl teeth or the second plurality of pawl teeth with the ratchet gear teeth. The pawl further includes a rear surface defining a midpoint of the rear surface. The pawl further defines a midplane intersecting the midpoint of the front surface and the midpoint of the rear surface. The rear surface further defines an engagement surface disposed in an engagement plane, the engagement plane being disposed at a selected angle relative to the midplane. When the biasing member contacts the pawl at the midplane of the pawl, the engagement surface creates an instability between the biasing member and the pawl such that the pawl is forced in a first rotational direction or a second rotational direction.

[0013] In one example, the selected angle of the engagement surface is non - perpendicular. In another example, the engagement surface is inclined relative to the midplane of the pawl.

[0014] In one example, the engagement surface of the pawl includes a first concave curve, a second concave curve, and a convex curve formed between the first concave curve and the second concave curve. In another example, the convex curve is eccentrically positioned relative to the midplane of the pawl, and the tangent of the convex curve forms a non - perpendicular angle relative to the midplane of the pawl. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following is a brief description of the drawings associated with the present disclosure, which will be discussed in more detail in the Detailed Description section below.

[0016] Figure 1 An exploded perspective view of a ratchet head of a ratchet tool is illustrated.

[0017] Figure 2 A top perspective view of the front side of the ratchet head is illustrated, showing the ratchet assembly positioned in a first position (clockwise position) within the ratchet assembly cavity.

[0018] Figure 3 A perspective view of the pawl is illustrated, showing the front surface of the pawl.

[0019] Figure 4 A reference according to one aspect of the present disclosure is illustrated Figure 6 The top plan view of the pawl shown.

[0020] Figure 5 A bottom rear perspective view of the pawl is illustrated, showing the rear surface of the pawl.

[0021] Figure 6The top plan view of the pawl is shown, which shows the engaging surface of the pawl.

[0022] Figure 7 The reference is shown Figure 8 The top plan view of the ratchet assembly shown in the first position (clockwise position).

[0023] Figure 8 The top plan view of the biasing member and the pawl is shown, which shows the relative forces of the biasing member and the pawl in the first position (clockwise position).

[0024] Figure 9 The reference is shown Figure 10 The top plan view of the ratchet assembly shown in the temporary position.

[0025] Figure 10 The top plan view of the biasing member and the pawl is shown, which shows the relative forces of the biasing member and the pawl in the temporary position.

[0026] Figure 11 The reference is shown Figure 12 The top plan view of the ratchet assembly shown in the second position (counterclockwise position).

[0027] Figure 12 The top plan view of the biasing member and the pawl is shown, which shows the relative forces of the biasing member and the pawl in the second position (counterclockwise position).

[0028] Figure 13 The top plan view of an alternative configuration of the pawl is shown.

[0029] Figure 14 The reference is shown Figure 13 The detailed top plan view of the portion of the pawl identified in

[0030] Figure 15 The reference is shown Figure 13 of the biasing member and the pawl, which shows the relative forces of the biasing member and the pawl in the temporary position.

[0031] When read in conjunction with the accompanying drawings, the foregoing summary of the invention and the following detailed description of certain features of the present application can be better understood. For purposes of illustration, certain features are shown in the drawings. However, it should be understood that the claims are not limited to the arrangements shown in the drawings. Although specific features of various embodiments may be shown in some drawings and not in others, this is merely for convenience. Any feature of any drawing may be cited and / or claimed in combination with any feature of any other drawing.

[0032] Unless otherwise indicated, the drawings provided herein are intended to illustrate features of embodiments of the present disclosure. These features are believed to be applicable in a wide variety of applications including one or more embodiments of the present disclosure. Thus, the drawings are not intended to include all conventional features known to a person of ordinary skill in the art that are necessary for the practice of the embodiments disclosed herein. Detailed Description

[0033] The present disclosure relates to a ratchet tool that enables a user to selectively determine the direction (i.e., clockwise or counterclockwise) in which torque is applied to a workpiece (not shown). Among other factors, a reliable ratchet tool requires stable and dynamic engagement of the internal and / or external components of the tool. In Figure 1 an exploded view of which the ratchet tool 1 is shown. Figure 1 The x-axis, y-axis, and z-axis are also shown in Figure 1 to assist in describing various movements and relationships of the internal components of the ratchet tool 1. As illustrated, the ratchet tool 1 of the present disclosure includes a ratchet assembly 20 that includes a sleeve 40, a ratchet gear 50, a switch 60, a biasing member 70, and a pawl 100. The ratchet assembly 20 is disposed in a ratchet assembly cavity 13 of a ratchet head 2. The ratchet assembly cavity 13 includes a bottom surface 9, a gear sidewall 10, a first sidewall 16, a second sidewall 17, and a switch-sleeve cavity 14 that is operable to receive the switch 60 and the sleeve 40. The gear sidewall 10 extends from the first sidewall 16 and the second sidewall 17 to form an arcuate shape that is substantially complementary to the shape of the ratchet gear 50. As

[0034] shown in Figure 2As shown in FIG. The sleeve 40 further includes at least one anchor 42 operable to engage at least one pocket 15 disposed in the switch-sleeve cavity 14 such that the sleeve 40 stabilizes the switch 60 within the ratchet head 2, specifically within the switch-sleeve cavity 14. The sleeve 40 further includes a first portion 44 and a second portion 45 disposed at opposite ends of the body 41, the first portion and the second portion operable to restrict rotation of the switch 60 along the y-axis in a clockwise or counterclockwise direction. It should be understood that the present disclosure contemplates a ratchet tool 1 that does not include the sleeve 40.

[0035] As Figure 1 and Figure 2 shown in FIGS., the ratchet gear 50 is rotatably disposed in the ratchet assembly cavity 13 and includes a drive member 52 for transmitting torque to a workpiece (not shown). The ratchet gear 50 defines a perimeter 53 and a plurality of gear teeth 54 disposed about the perimeter 53 for selectively engaging the pawl 100. The drive member 52 is operable to engage a socket, fastener, or other tool. As shown, the drive member 52 has a substantially square shape, but may also have a rectangular or other shape. The drive member 52 may optionally include a ball detent operable to engage a conventional socket.

[0036] As Figure 1 and Figure 2 shown in FIGS., the switch 60 is rotatably disposed through the switch hole 19 and is positioned adjacent to the switch pocket 43 of the sleeve 40. The switch 60 includes a switch body 62 and a first flange 63 that extends away from the central z-axis 65 of the switch body 62 or extends laterally from the central z-axis. The switch 60 further includes a second flange 64 that extends away from the central z-axis 65 of the switch body 62 or extends laterally from the central z-axis. A portion of the pawl 100 is received between the first flange 63 and the second flange 64, thereby restricting movement of the pawl 100 along the y-axis when the switch 60 is rotated clockwise or counterclockwise. As Figure 1 shown in FIGS., the first flange 63 is positioned on one side of the biasing member 70, and the second flange 64 is positioned on the side of the biasing member 70 opposite the side on which the first flange 63 is positioned.

[0037] The user can activate the switch 60 via a switch lever 66 positioned on the rear side 12 of the ratchet head 2, which is opposite to the front side 11 of the ratchet head 2. The user can rotate the switch 60 clockwise or counterclockwise along the y-axis via the lever 66 to move the pawl 100 into engagement with the ratchet gear 50. In the illustrated embodiment, the switch 60 defines a hole 67 configured to partially receive a biasing member 70 including a pin 72. The pin 72 includes a body 73 and a head 74, wherein the head 74 includes a non-planar surface 75 operable to contact the pawl 100. The biasing member 70 further includes a central axis 71 that intersects the midpoint of the non-planar surface 75 of the pin 72. As Figure 1 shown, the biasing member 70 further includes a spring 76. The biasing member 70 uses elastic potential energy (i.e., the biasing force generated by the compression of the spring 76) to push the pin 72 into engagement with the rear surface 120 of the pawl 100, thereby pushing the pawl 100 against the ratchet gear 50.

[0038] As Figure 1 and Figure 2 shown, the pawl 100 includes a body 102 having a circular shape that conforms to a portion of the perimeter 53 of the ratchet gear 50. The pawl 100 further includes at least one or more extension portions 103 disposed on opposite sides of a recess 104. In the embodiment shown in Figure 2 , a first flange 63 of the switch 60 overlaps the recess 104 of the pawl 100 between the extension portions 103 such that the switch 60 does not rest on or interfere with the pawl 100. Further, as shown in detail in Figures 3 to 6 , the pawl 100 includes a front surface 110 and a rear surface 120. The front surface 110 includes a front surface midpoint 111 and a first plurality of pawl teeth 112 disposed on a first side 113 of the front surface midpoint 111. The front surface 110 further includes a second plurality of pawl teeth 114 disposed on a second side 115 of the front surface midpoint 111. As shown in Figure 2 , the first plurality of pawl teeth 112 and the second plurality of pawl teeth 114 are operable to selectively engage the ratchet gear teeth 54 to limit the rotation of the ratchet gear 50 about the y-axis in a first rotational direction 203 (clockwise) or a second rotational direction 204 (counterclockwise). As shown in Figures 4 to 6 , the rear surface 120 further defines a rear surface midpoint 121 and an engagement surface 122 disposed in an engagement plane (not shown). The pawl 100 further includes a midplane 101 that intersects the front surface midpoint 111 and the rear surface midpoint 121. The biasing member 70 is operable to contact and engage the engagement surface 122 of the pawl 100.

[0039] The shape of the rear surface 120 of the pawl 100 and the engagement between the rear surface 120 and the biasing member 70 are operable to generate a net force that biases the pawl 100 and the ratchet gear 50 away from the midplane 101 when the biasing member 70 contacts the rear surface 120 of the pawl 100 near the midplane 101. This ensures that the pawl 100 does not position itself in a central rest position where gear slip or failure may occur, or a position where the pawl 100 and / or the ratchet gear 50 may undesirably or inadvertently move in the first or second rotational directions. For example, in Figure 6 the illustrated embodiment, the engagement surface 122 of the pawl 100 includes a convex curve 130 formed between a first concave curve 133 and a second concave curve 136. Both the first concave curve 133 and the second concave curve 136 each define a parabola 134, 137, wherein the parabola 134 of the first concave curve 133 disposed in the first plane is shallower than the parabola 137 of the second concave curve 136 disposed in the second plane. For example, the bottom of the parabola 134 of the first concave curve 133 defines a first depth relative to the convex curve 130. Similarly, the bottom of the parabola 137 of the second concave curve 136 defines a second depth relative to the convex curve 130. In a preferred embodiment, the first depth of the first concave curve 133 is less than the second depth of the second concave curve 136. In other words, the bottom of the parabola 137 of the second concave curve 136 is formed at a greater depth in the body of the pawl 100 than the bottom of the parabola 134 of the first concave curve 133. As Figure 6 shown, the convex curve 130 is eccentrically positioned relative to the midplane 101 of the pawl 100 such that the convex curve midplane 131 and the midplane 101 of the pawl 100 are offset from each other. Thus, the engagement surface 122 (specifically, the convex curve 130) is not perpendicular to the midplane 101 of the pawl 100 at the rear surface midpoint 121. In the illustrated embodiment, the engagement surface 122 is disposed at a selected angle relative to the midplane 101 of the pawl 100. It should be understood that the present disclosure contemplates an engagement surface 122 wherein the first depth of the first concave curve 133 is greater than the second depth of the second concave curve 136 such that the bottom of the parabola 134 of the first concave curve 133 is formed at a greater depth in the body of the pawl 100 than the bottom of the parabola 137 of the second concave curve 136. It should be further understood that the present disclosure is not limited to the exact curvatures shown in the illustrated embodiment, but contemplates any curvature sufficient to ensure that the engagement surface 122 is not perpendicular to the midplane 101 at the midplane 101.

[0040] As Figures 7 to 12As shown, when the non-planar surface 75 of the biasing member 70 contacts the rear surface midpoint 121 at the mid-plane 101 of the pawl 100, an instability is created between the engaging surface 122 of the biasing member 70 and the pawl 100. When the instability is at the mid-plane 101 of the pawl 100, the net force vector 200 created by the shape of the engaging surface 122 and the biasing force applied by the biasing member 70 guides the pawl 100 away from the mid-plane 101. For example, in Figure 7 when the rod 66 is activated and the switch 60 and the biasing member 70 rotate counterclockwise, the pawl 100 wedges against the first sidewall 16 in the first rotational direction 203 through the biasing member 70 and the ratchet gear 50. The position of the pawl 100 relative to the ratchet gear 50, specifically the engagement of the pawl teeth 112 with the gear teeth 54, restricts the rotation of the ratchet gear 50 in the clockwise direction such that torque can be applied to a workpiece (not shown) in the clockwise direction. In this position, as Figure 8 shown, the net force between the biasing member 70 and the pawl 100 is zero, where the biasing force vector 202 (created by the spring 76) is opposite to the normal force vector 201 of the first concave curve 133. As shown, the normal force vector 201 of the first concave curve 133 is perpendicular to the tangent 135 of the first concave curve 133. The net zero force between the biasing member 70 and the pawl 100 helps to hold the pawl 100 and the ratchet gear 50 in the Figure 7 and Figure 8 first position (clockwise position) shown.

[0041] As Figure 9 shown, when the pawl 100 and the ratchet gear 50 move in the second rotational direction 204 from the activated switch 60, the biasing member 70 moves across the engaging surface 122 of the pawl 100. When the biasing member 70 contacts or approaches the rear surface midpoint 121 at the mid-plane 101 of the pawl 100, the ratchet gear assembly 20 is in a temporary position. In this temporary position, the central axis 71 of the biasing member 70 coincides with the mid-plane 101 of the pawl 100 and the mid-plane 51 of the ratchet gear 50. Due to the selected angle of the engaging surface 122 relative to the mid-plane 101 of the pawl 100, an instability is created between the biasing member 70 and the pawl 100 at the rear surface midpoint 121. As Figure 10As shown, the tangent line 132 of the convex curve 130 forms a non-perpendicular angle with the middle plane 101 of the pawl 100. The normal force vector 201 of the convex curve 130 is perpendicular to the tangent line 132 of the convex curve 130. When the biasing member 70 contacts the midpoint 121 of the rear surface at the middle plane 101 of the pawl 100, the normal force vector 201 of the convex curve 130 forms an angle with the biasing force vector 202 of the biasing member 70. Similarly, the central axis 71 of the biasing member 70 and the biasing force vector 202 form non-perpendicular angles with the engaging surface 122 of the pawl 100. The non-zero sum of the biasing force vector 202 and the normal force vector 201 of the convex curve 130 produces a net force vector 200 that causes the biasing member 70 and the pawl 100 to move away from the middle plane 101.

[0042] It should be understood that although Figure 9 and Figure 10 the illustrated embodiments of depict the biasing member 70 as being in a direct line with the middle plane 101 of the pawl 100, the shape of the engaging surface 122 ensures that there is instability between the biasing member 70 and the pawl 100 across the entire convex curve 130. In other words, whenever the pawl 100 is not in place in the first or second position, the pawl 100 is biased towards the first position (clockwise) or the second position (counterclockwise). As illustrated, whenever the biasing member 70 is positioned to the right of the middle plane 131 of the pawl, the pawl 100 is biased into the second position. Similarly, whenever the biasing member 70 is positioned to the left of the middle plane 131 of the pawl, the pawl 100 is biased into the first position.

[0043] As Figure 10 and Figure 11 shown in the illustrated embodiments of, the net force vector 200 causes the biasing member 70 and the pawl 100 to move to the second position (counterclockwise position) in the second rotational direction 204, at which position the pawl 100 wedges against the second sidewall 17 by the biasing member 70 and the ratchet gear 50. As Figure 12As shown, the net force between the biasing member 70 and the pawl 100 is zero, where the biasing force vector 202 is opposite to the normal force vector 201 of the second concave curve 136. The normal force vector 201 of the second concave curve 136 is perpendicular to the tangent 138 of the second concave curve 136. The zero net force between the biasing member 70 and the pawl 100 helps to hold the pawl 100 and the ratchet gear 50 in the second position (counterclockwise position). This position of the pawl 100 relative to the ratchet gear 50, specifically the engagement of the pawl teeth 112 with the gear teeth 54, restricts the counterclockwise rotation of the ratchet gear 50 such that torque can be applied to a workpiece (not shown) in the counterclockwise direction. Further, to move the pawl 100 and the ratchet gear 50 back to the first position (clockwise position) along the first rotation direction 203, the user can rotate the switch 60 counterclockwise with sufficient force via the lever 66 to overcome the net force vector 200 generated at the midplane 101 of the pawl 100.

[0044] The present disclosure also contemplates alternative convex curve embodiments where the engagement surface 122 is biased in a manner opposite to that shown in the illustrated embodiment. In such embodiments (not shown), the engagement surface 122 includes a parabola 134 of the first concave curve 133 that is deeper than the parabola 137 of the second concave curve 136. Thus, at the midplane 101, the net force vector 200 biases the pawl 100 in the first rotation direction 203.

[0045] As described above, the biasing action between the engagement surface 122 and the biasing member 70 is operable to bias (such that) the pawl 100 and the ratchet gear 50 in the first rotation direction 203 or the second rotation direction 204. In other words, the configurations disclosed herein ensure that when the biasing member 70 is at the midplane of the pawl 101, and when the pawl 100 is not positioned in the first or second position, and when contacting the rear surface midpoint 121 at any point along the engagement surface 122, the net force between the biasing member 70 and the pawl 100 and the ratchet gear 50 is not zero. In use, the biasing action continuously biases the pawl 100 and the ratchet gear 50 towards the first sidewall 16 or the second sidewall 17 in the first rotation direction 203 or the second rotation direction 204, respectively. By preventing the pawl 100 from positioning itself in the central rest position, the present disclosure provides a more reliable ratchet tool 1.

[0046] The present disclosure also contemplates different geometries of the rear surface 120 of the pawl 100 that similarly create instability, i.e., a biasing action, between the biasing member 70 and the rear surface 120 of the pawl 100 at the rear surface midpoint 121. Figure 13Illustrated is the configuration of the rear surface 120 of the pawl 100, wherein the engaging surface 122 is inclined. This alternative configuration also creates a biasing action between the biasing member 70 and the rear surface 120 of the pawl 100 at the rear surface midpoint 121. As Figure 13 and Figure 14 shown, the inclined engaging surface 122 includes a planar surface 140 that is disposed in the engagement plane between the first concave curve 143 and the second concave curve 146. Both the first concave curve 143 and the second concave curve 146 each define a parabola 144, 147, wherein the parabola 144 of the first concave curve 143 disposed in the first plane is shallower than the parabola 147 of the second concave curve 146 disposed in the second plane. Since the parabola 144 of the first concave curve 143 is shallower than the parabola 147 of the second concave curve 146, the planar surface 140 is inclined at the rear surface midpoint 121 in the midplane of the pawl 101. For example, the bottom of the parabola 144 of the first concave curve 143 defines a first depth relative to the planar surface 140. Similarly, the bottom of the parabola 147 of the second concave curve 146 defines a second depth relative to the planar surface 140. In a preferred embodiment, the first depth of the first concave curve 143 is less than the second depth of the second concave curve 146. In other words, the bottom of the parabola 147 of the second concave curve 146 is formed at a greater depth in the body of the pawl 100 than the bottom of the parabola 144 of the first concave curve 143. It should be understood that the present disclosure contemplates different degrees of slope of the inclined engaging surface 122 of the pawl 100 such that the inclined engaging surface 122 is disposed at a selected angle relative to the midplane 101 of the pawl 100.

[0047] As Figure 15As shown, the planar surface 140 forms a non - perpendicular angle relative to the central plane 101 of the pawl 100 at the mid - point 121 of the rear surface. The normal force vector 201 of the planar surface 140 is perpendicular to the planar surface 140. In the case where the biasing member 70 contacts the mid - point 121 of the rear surface at the central plane 101 of the pawl 100, the normal force vector 201 of the planar surface 140 is angled relative to the biasing force vector 202 of the biasing member 70. In the temporary position, the central axis 71 of the biasing member 71 coincides with the central plane 101 of the pawl 100 and the central plane 51 of the ratchet gear 50. As shown, the central axis 71 of the biasing member 70 and the biasing force vector 202 form a non - perpendicular angle with the engaging surface 122 of the pawl 100. The non - zero sum of the biasing force vector 202 and the normal force vector 201 of the planar surface 140 produces a net force vector 200 that biases the biasing member 70 and the pawl 100 away from the central plane 101. As illustrated, the net force vector 200 biases the pawl 100 towards the second position. Thus, the instability between the planar surface 140 and the biasing member 70 is operable to push the pawl 100 and the ratchet gear 50 forcefully in the first rotational direction 203 or the second rotational direction 204. It should be understood that the present disclosure contemplates an inclined engaging surface 122 that is a mirror image of the inclined engaging surface 122 shown in the figure. It should also be understood that the inclined engaging surface 122 can be mirrored (not shown) such that the pawl 100 is generally biased into the first position.

[0048] The present disclosure has been described in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains to practice the disclosure. It should be understood that the foregoing description of the preferred aspects and modifications of the present disclosure may be made therein without departing from the spirit or scope of the present disclosure as set forth in the appended claims. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions. Thus, this application is not intended to be limited to the particular aspects disclosed, but this application will include all aspects falling within the scope of the appended claims.

Claims

1. A ratchet tool, comprising: A ratchet head, the ratchet head comprising: A ratchet assembly cavity; A ratchet gear rotatably disposed in the ratchet assembly cavity, wherein the ratchet gear includes a drive member for transmitting torque to a workpiece, and wherein the ratchet gear defines a perimeter and a plurality of ratchet gear teeth disposed around the perimeter; A pawl operable to selectively engage with the ratchet gear, the pawl comprising: A front surface defining a midpoint of the front surface, the front surface including a first plurality of pawl teeth disposed on a first side of the midpoint of the front surface and capable of selectively engaging with the ratchet gear teeth, and a second plurality of pawl teeth disposed on a second side of the midpoint of the front surface and capable of selectively engaging with the ratchet gear teeth, the pawl being operable to selectively engage either the first plurality of pawl teeth or the second plurality of pawl teeth with the ratchet gear teeth to restrict rotation of the ratchet gear in one of a first rotational direction or a second rotational direction, and A rear surface defining a midpoint of the rear surface, the pawl defining a midplane intersecting the midpoint of the front surface and the midpoint of the rear surface, the rear surface further defining an engagement surface disposed in an engagement plane, the engagement plane being disposed at a selected angle relative to the midplane; and A switch disposed through a switch hole in the ratchet assembly cavity, wherein the switch includes a biasing member operable to engage the rear surface of the pawl such that the biasing member pushes the pawl against the ratchet gear.

2. The ratchet tool according to claim 1, wherein The selected angle of the engagement surface is non-perpendicular.

3. The ratchet tool according to claim 2, wherein, The engagement surface is inclined relative to the midplane of the pawl.

4. The ratchet tool according to claim 3, wherein, At the midplane of the pawl and the midplane of the ratchet gear, the engagement surface creates instability between the biasing member and the pawl such that the pawl is subjected to a force in the first rotational direction or the second rotational direction.

5. The ratchet tool according to claim 1, wherein, The engagement surface of the pawl further includes: A first concave curve; A second concave curve; and A convex curve formed between the first concave curve and the second concave curve.

6. The ratchet tool according to claim 5, wherein, The convex curve is eccentrically positioned relative to the midplane of the pawl, and a tangent of the convex curve forms a non-perpendicular angle relative to the midplane of the pawl.

7. The ratchet tool according to claim 6, wherein, At the midplane of the pawl and the midplane of the ratchet gear, the convex curve creates instability between the biasing member and the pawl such that the pawl is subjected to a force in the first rotational direction or the second rotational direction.

8. The ratchet tool according to claim 1, wherein, The biasing member includes a spring and a pin, the spring and the pin being at least partially disposed within the switch.

9. The ratchet tool according to claim 8, wherein, The pin further includes a body and a head, the head including a non-planar surface.

10. A ratchet tool, comprising: A ratchet head, the ratchet head comprising: A ratchet assembly cavity; A ratchet gear rotatably disposed in the ratchet assembly cavity, wherein the ratchet gear includes a drive member for transmitting torque to a workpiece, and wherein the ratchet gear defines a perimeter and a plurality of ratchet gear teeth disposed around the perimeter; A pawl operable to selectively engage with the ratchet gear, the pawl comprising: A front surface defining a midpoint of the front surface, the front surface including a first plurality of pawl teeth disposed on a first side of the midpoint of the front surface and capable of selectively engaging with the ratchet gear teeth, and a second plurality of pawl teeth disposed on a second side of the midpoint of the front surface and capable of selectively engaging with the ratchet gear teeth, the pawl being operable to selectively engage either the first plurality of pawl teeth or the second plurality of pawl teeth with the ratchet gear teeth to restrict rotation of the ratchet gear in one of a first rotational direction or a second rotational direction, and A rear surface defining a midpoint of the rear surface, the pawl defining a midplane intersecting the midpoint of the front surface and the midpoint of the rear surface, the rear surface further defining a mating surface disposed in a mating plane; A switch disposed to pass through a switch hole in the ratchet assembly cavity; and A biasing member partially disposed within the switch and operable to engage the mating surface of the pawl such that the biasing member urges the pawl against the ratchet gear, wherein when the biasing member contacts the mating surface of the pawl, a central axis of the biasing member and the mating surface of the pawl form a non-perpendicular angle.

11. The ratchet tool according to claim 10, wherein, The mating surface is inclined relative to the midplane of the pawl.

12. The ratchet tool according to claim 11, wherein, At the midplane of the pawl and the midplane of the ratchet gear, the mating surface creates instability between the biasing member and the pawl such that the pawl is subjected to a force in the first rotational direction or the second rotational direction.

13. The ratchet tool according to claim 10, wherein, The mating surface of the pawl further includes: A first concave curve; A second concave curve; and A convex curve formed between the first concave curve and the second concave curve.

14. The ratchet tool according to claim 13, wherein, The convex curve is eccentrically positioned relative to the midplane of the pawl, and a tangent to the convex curve forms a non-perpendicular angle relative to the midplane of the pawl.

15. The ratchet tool according to claim 14, wherein, At the midplane of the pawl and the midplane of the ratchet gear, the convex curve creates instability between the biasing member and the pawl such that the pawl is subjected to a force in the first rotational direction or the second rotational direction.

16. A pawl for a ratchet tool, the pawl comprising: A front surface defining a midpoint of the front surface, the front surface including a first plurality of pawl teeth disposed on a first side of the midpoint of the front surface and capable of selectively engaging with a plurality of ratchet gear teeth, and a second plurality of pawl teeth disposed on a second side of the midpoint of the front surface and capable of selectively engaging with the ratchet gear teeth, the pawl being operable to selectively engage either the first plurality of pawl teeth or the second plurality of pawl teeth with the ratchet gear teeth; And A rear surface defining a midpoint of the rear surface, the pawl defining a midplane intersecting the midpoint of the front surface and the midpoint of the rear surface, the rear surface further defining a mating surface disposed in a mating plane, the mating plane being disposed at a selected angle relative to the midplane, Wherein, when the biasing member contacts the pawl at the mid-plane of the pawl, the engagement surface creates instability between the biasing member and the pawl such that the pawl is forced in a first rotational direction or a second rotational direction.

17. The pawl according to claim 16, wherein The selected angle of the engagement surface is non-perpendicular.

18. The pawl according to claim 17, wherein, The engagement surface is inclined with respect to the mid-plane of the pawl.

19. The pawl according to claim 16, wherein, The engagement surface of the pawl further comprises: a first concave curve; a second concave curve; and a convex curve formed between the first concave curve and the second concave curve.

20. The pawl according to claim 19, wherein, The convex curve is eccentrically positioned with respect to the mid-plane of the pawl, and a tangent to the convex curve forms a non-perpendicular angle with respect to the mid-plane of the pawl.

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