Patent Publication Number: US-2020298379-A1

Title: Ratchet Mechanism for Tool

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     The present application is a continuation of U.S. application Ser. No. 15/709,131, filed on Sep. 19, 2017, which claims the benefit of and priority to U.S. Provisional Application No. 62/397,247, filed on Sep. 20, 2016, which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     The present invention relates generally to the field of tools. The present invention relates specifically to a tool with a ratchet mechanism, such as a ratchet, a combo wrench with ratchet mechanism, socket wrench with ratchet mechanism, screw driver with ratchet mechanism, etc. Ratchet mechanisms are used in a variety of tools that use a twisting or rotating motion of the tool, typically to drive a fastener component (e.g., a nut, a bolt, a screw, etc.), and the ratchet mechanism allows the tool or tool handle to be rotated relative to the fastening component to reset the handle position without driving the fastening component and without requiring the tool to be disengaged from the fastening component. 
     SUMMARY OF THE INVENTION 
     One embodiment of the invention relates to a tool. The tool includes a tool body including workpiece engagement surfaces and a ratcheting mechanism coupled to the workpiece engagement structure. The ratcheting mechanism includes a gear structure having a plurality of gear teeth, and a pawl structure having a plurality of pawl teeth engaged with the gear teeth. The pawl structure includes a pawl body integral with the pawl teeth formed from an elastic material that biases the pawl teeth against the gear teeth, that allows the pawl body to flex away from the gear teeth which allows the pawl teeth to rotate past the gear teeth in a first rotational direction, and that allows the pawl teeth to engage the gear teeth such that the pawl teeth are rotationally fixed relative to the gear teeth in a second rotational direction. 
     In various embodiments, the pawl structure includes at least two arms extending from a pawl body, and each of the pawl arms include at least one pawl tooth. The pawl teeth of the arms are shaped and/or positioned relative to each other such that the maximum distance from a leading surface of one of the pawl teeth to the closest adjacent engagement surface of one of the gear teeth is less than or equal to a gear tooth spacing distance (e.g., an arc length between opposing portions of adjacent gear teeth) divided by the number of pawl arms. In a specific embodiment, the number of pawl arms is two and the maximum distance from a leading surface of one of the pawl teeth to the closest adjacent engagement surface of one of the gear teeth is less than or equal to one half of the gear tooth spacing distance. In a specific embodiment, the number of pawl arms is six and the maximum distance from a leading surface of one of the pawl teeth to the closest adjacent engagement surface of one of the gear teeth is less than or equal to one sixth of the gear tooth spacing distance. 
     In specific embodiments, the pawl body includes a central trunk coupled at a first end to a base and coupled at a second end to a pair of pawl arms both extending away from the central trunk. In some such embodiments, one of the pawl arms also extends in a clockwise direction, and the other extends in a counterclockwise direction. The pawl teeth are located at the ends of both of the pawl arms opposite of the pawl base. The pawl structure is shaped relative to the gear teeth such that during rotation in the first direction, the pawl teeth of each arm alternate in engagement with the gear teeth. 
     In specific embodiments, the pawl structure is shaped relative to the gear teeth such that during rotation in the second direction, the pawl teeth of only one of the arms engages with the gear teeth. In specific embodiments, a medial axis of the tool body traverses the pawl structure, and the pawl structure is shaped such that it is non-symmetrical relative to the medial axis of the tool body. In a specific embodiment, a buttress structure formed in the tool body is positioned to engage a surface of the pawl structure during rotation in the second direction, and the buttress structure is located on the opposite side of the medial axis from at least one of the arms of the pawl structure. 
     In various embodiments, at least one portion of the pawl body is formed from an elastic material biasing the pawl teeth. In specific embodiments, at least one of the central trunk and the pawl arms are formed from the elastic material biasing the pawl teeth. In specific embodiments, the central trunk and the pawl arms formed from a metal material that is contiguous and continuous with the material of the pawl teeth. 
     In a specific embodiment, the gear teeth extend radially outward and away from the workpiece engagement surfaces, and the pawl teeth extend radially inward toward the gear teeth and the workpiece engagement surfaces. In a specific embodiment, the pawl structure is located between the gear teeth and the tool body. In a specific embodiment, the ratchet mechanism does not include a separate spring element (e.g., a coil spring) that is separate from the pawl body for biasing the pawl teeth. 
     In other specific embodiments, the pawl structure includes a central body defining an opening, and the workpiece engagement structures are located in the opening. In this embodiment, the pawl teeth extend radially outward and away from the workpiece engagement surfaces, and the gear teeth extend radially inward toward the gear teeth and the workpiece engagement surfaces. In a specific embodiment, the pawl structure includes a plurality of arms extending in the circumferential direction around the pawl body, and the pawl teeth extend radially outward from ends of the arms. In a specific embodiment, a flexible hinge structure couples each pawl arm to the pawl central body. In some such embodiments, the hinge structure is formed from a metal material that is contiguous and continuous with the material of both the pawl arms and the pawl central body. 
     In a specific embodiment, the gear teeth are located between the pawl structure and the tool body. In a specific embodiment, the gear teeth and/or pawl teeth surround at least 180 degrees of the workpiece engagement surfaces. In a specific embodiment, the gear teeth are evenly spaced and completely surround the work piece engagement surfaces. In a specific embodiment, the pawl structure includes at least three pawl arms such that at least one of the pawl teeth are located within each 120 degree arc around the workpiece engagement surfaces. 
     Another embodiment relates to a driving tool. The driving tool includes a body, a workpiece engagement surface coupled to the body and a ratchet mechanism supported by the body and coupled to the workpiece engagement surface. The ratchet mechanism includes a gear structure coupled to the workpiece engagement surface, and the gear structure includes a plurality of gear teeth. The ratchet mechanism includes a pawl structure including a pawl body, pawl teeth and a spring joint coupling the pawl teeth to the pawl body. The pawl body, the pawl teeth and the spring joint are all formed from a single integral piece of metal material. An elasticity of the metal material within the spring j oint allows the pawl body to flex away from the gear teeth such that the pawl teeth rotate past the gear teeth when the body is rotated in a first rotational direction. The elasticity of the metal material within the spring joint biases the pawl teeth into engagement with the gear teeth such that the pawl teeth are rotationally fixed relative to the gear teeth in a second rotational direction allowing a torque applied to the body in the second rotational direction to translate through the ratchet mechanism to the workpiece engagement surface. 
     Another embodiment relates to a driving tool. The driving tool includes a body, a workpiece engagement surface coupled to the body and a ratchet mechanism supported by the body and coupled to the workpiece engagement surface. The ratchet mechanism includes a gear structure coupled to the workpiece engagement surface, and the gear structure includes a plurality of gear teeth. The ratchet mechanism includes a pawl body, a pawl tooth and a spring joint coupling the pawl tooth to the pawl body. The spring joint is located between the pawl body and the pawl tooth in a direction from the body toward the workpiece engagement surface. When the body is rotated in a first rotational direction, the spring joint bends allowing the pawl body to flex away from the gear teeth such that the pawl tooth rotates past the gear teeth. When the body is rotated in a second rotational direction, the spring joint biases the pawl tooth into engagement with the gear teeth such that the pawl tooth is rotationally fixed relative to the gear teeth. 
     Another embodiment relates to a ratcheting driving tool. The tool includes a body, a workpiece engagement surface coupled to the body and a gear structure coupled to and surrounding the workpiece engagement surface. The gear structure includes a plurality of gear teeth and an angular gear tooth spacing, GTS. The tool includes a pawl body, a plural nnumber of pawl arms coupled to and extending from the pawl body and a pawl tooth extending from each pawl arm toward the gear teeth. The tool includes a maximum backlash distance. A spacing between pawl teeth on adjacent pawl arms relative to the gear teeth is such that the maximum backlash distance, measured in degrees, is less than or equal to GTS divided by n. 
     Additional features and advantages will be set forth in the detailed description which follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary. 
     The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and together with the description serve to explain principles and operation of the various embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a tool including a ratcheting mechanism, according to an exemplary embodiment. 
         FIG. 2  is a perspective view of a ratchet mechanism of the tool of  FIG. 1 , according to an exemplary embodiment. 
         FIG. 3  is a top plan view of a pawl structure of the ratchet mechanism of  FIG. 2 , according to an exemplary embodiment. 
         FIG. 4  is a cross-sectional view of the ratcheting tool of  FIG. 1  showing the ratcheting mechanism of  FIG. 2  mounted within a tool body, according to an exemplary embodiment. 
         FIG. 5  is a top plan view showing a ratcheting mechanism mounted within a tool body, according to another exemplary embodiment. 
         FIG. 6  is a gear structure of the ratcheting mechanism of  FIG. 5 , according to an exemplary embodiment. 
         FIG. 7  is a top plan view of a pawl structure of the ratcheting mechanism of  FIG. 5  located within a tool body, according to an exemplary embodiment. 
         FIG. 8  is a perspective view of the pawl structure of  FIG. 7 , according to an exemplary embodiment. 
         FIG. 9  is a perspective view of a pawl unit, according to an exemplary embodiment. 
         FIG. 10  is a cross-sectional view of the ratcheting tool of  FIG. 5  showing the ratcheting mechanism mounted within a tool body, according to an exemplary embodiment. 
         FIG. 11  is a top plan view of a pawl unit of the pawl structure of  FIG. 7 , according to an exemplary embodiment. 
         FIG. 12  is a perspective view of a pawl structure from below, according to another exemplary embodiment. 
         FIG. 13  is a perspective view of a pawl unit of the pawl structure of  FIG. 12 , according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring generally to the figures, various embodiments of a ratchet mechanism for a tool are shown and described. In general, ratchet mechanisms are used in a variety of tools that deliver torque to a workpiece such as a component of fastener (e.g., a nut, a bolt, a screw, etc.). In various embodiments, the ratchet mechanisms discussed herein utilize a variety of innovative structures which reduce backlash (e.g., the amount of backward motion permitted before the ratchet mechanism engages stopping rotation of the ratchet). In addition, various embodiments of the ratchet mechanism discussed herein provide a high level of engagement between components of the ratchet mechanism during driving rotation (e.g., restricted rotation in which the ratchet mechanism transfers torque from the tool body/tool handle to the workpiece) such that forces are distributed across multiple engagement surfaces during use. In addition, the components of various embodiments of the ratchet mechanisms are configured relative to the tool body such that the tool body provides a high level of support to the components of the ratchet mechanism during driving. Both the tool body support and the high level of ratchet component engagement are believed to provide a ratchet mechanism with a high level of durability. 
     In an exemplary embodiment, the ratchet mechanism includes a toothed gear or sprocket and a branched or forked engagement structure, such as a forked pawl structure. The forked pawl includes a pair of arms extending from a central trunk. The arms and/or trunk of the forked pawl act as a spring bending in alternating directions to allow pawl teeth located at the ends of the arms to slide over the teeth of the gear during forward or unrestricted rotation of the ratchet mechanism. In contrast to a typical pawl structure, the spring action of the forked pawl discussed herein maintains a high level of contact between the pawl teeth and the gear teeth, which reduces backlash. 
     In another exemplary embodiment, the ratchet mechanism includes a toothed ring structure and a generally annular engagement structure or pawl structure located within the toothed ring structure. In this arrangement, the gear includes inward facing teeth, which engage with outward facing teeth of the annular pawl. The annular pawl includes a plurality of engagement arms and plurality of engagement teeth located at the ends of the engagement arms. The engagement arms are shaped in an arc-shape and extend generally in the circumferential direction. Each engagement arm acts as a spring allowing the teeth to slide over the teeth of the gear during forward or unrestricted rotation of the ratchet mechanism. Similar to the prior embodiment, the spring action of the engagement arms discussed herein maintains a high level of contact between the pawl teeth and the gear teeth, which reduces backlash. 
     In a specific embodiment, the annular pawl structure is formed from multiple layers of similarly shaped annular structures stacked on top of each other. In such embodiments, each layer of the stack is rotationally offset from each other. This rotational offset increases the number of circumferentially spaced pawl surfaces that are available to engage with the gear teeth, which in turn decreases the amount of backlash experienced by the pawl mechanism. 
     Referring to  FIG. 1 , a tool, such as wrench  10 , is shown according to an exemplary embodiment. In the embodiment shown, wrench  10  is a combination wrench including a tool body  12 , an open wrench end  14  and a ratchet head or end  16 . Ratchet head  16  is formed from a generally ring shaped portion  18  of tool body  12  that surrounds and supports wrench engagement surfaces  20 . As will be understood, in use, wrench engagement surfaces  20  engage a component of a workpiece (e.g., a fastener, a bolt, a nut, etc.), and tool body  12  acts as a handle and a lever to apply torque to the component. 
     Wrench  10  includes a ratchet mechanism  22  that is supported within a tool body  12 , and ratchet mechanism  22  provides ratcheting action to wrench engagement surfaces  20 . In general, ratchet mechanism  22  is a mechanical structure that allows for free or unrestricted rotation of tool body  12  around engagement surfaces  20  in a first direction, shown as arrow  24 , and allows for restricted or driving rotation of tool body  12  around engagement surfaces  20  in a second direction  26 . In general, during rotation in the unrestricted direction  24 , ratchet mechanism  22  allows tool body  12  to rotate around engagement surfaces  20  (and around a fastening component located within engagement surfaces  20 ) without transferring torque to engagement surfaces  20 , and during rotation in the restricted direction  26 , ratchet mechanism  22  prevents tool body  12  from freely rotating around engagement surfaces  20  (and around a fastening component located within engagement surfaces  20 ) such that torque applied to tool body  12  is transferred to engagement surfaces  20  and to the fastening component located within engagement surfaces  20 . 
     Referring to  FIGS. 2-4 , components of ratchet mechanism  22  are shown in detail. As shown in  FIG. 2 , ratchet mechanism  22  includes a sprocket or gear  30 . Gear  30  is a generally ring or annularly shaped structure that includes an inner surface that defines an opening in which engagement surfaces  20  are located. The outer surface of gear  30  includes a plurality of teeth  32  which face radially outward from gear  30 . 
     Ratchet mechanism  22  includes a forked or branched engagement structure, shown as a forked pawl  34 . Referring to  FIG. 3 , forked pawl  34  includes a base  36 , a central body  38 , a first arm  40  and a second arm  42 . First arm  40  includes a plurality of teeth  44  located at the end of arm  40  opposite of base  36 , and second arm  42  includes a plurality of teeth  46  located at the end of arm  42  opposite of base  36 . In general, forked pawl  34  is configured to have both rigidity sufficient to engage and drive engagement surfaces  20  during restricted rotation  26 , and elasticity/spring action sufficient to allow the outer surfaces of teeth  44  and  46  to slide over gear teeth  32  during unrestricted/ratchet rotation  24 . In contrast to typical pawl structures that utilize a helical coil compression spring to bias the pawl into engagement, forked pawl  34  utilizes the elasticity of the material of body  38  and/or arms  40  and  42  to provide the biasing and flexibility needed to provide the ratcheting movement discussed herein. 
     Referring to  FIGS. 3 and 4 , details of the structure and operation of forked pawl  34  are explained in more detail. As tool body  12  is rotated in the direction of arrow  24 , clockwise facing surfaces of teeth  44  engage with teeth  32  of gear  30 , shown in area  48 . Due to the spacing and relative shape of pawl teeth  44  and gear teeth  32 , arm  40  and/or central body  38  bends or deflects upon engagement between pawl teeth  44  and gear teeth  32  during rotation in direction  24  which allows pawl teeth  44  to slide over gear teeth  32 . Once pawl teeth  44  pass over one of the gear teeth, the elasticity/spring action of arm  40  and/or central body  38  biases pawl teeth  44  into the space located before the next gear tooth  32  as rotation in direction  24  continues. In specific embodiments, the elasticity/spring action of arm  40  and/or central body  38  of pawl  34  is selected to ensure that the amount of force that needs to be applied to the tool handle/body during freewheeling/ratcheting motion is below a threshold, and in particular embodiments, the freewheeling ratcheting threshold is less than 4 lbs., specifically less than 2 lbs., and more specifically is less than 0.5 lbs. In specific embodiments, arms  40  and  42  each include multiple (specifically four) pawl teeth  44  and  46 , respectively. In various embodiments, multiple pawl teeth  44  and  46  allow for better/even load distribution across the pawl teeth surfaces during driving engagement (when the tool is rotated in the direction of arrow  26 ). 
     Upon continued rotation in direction  24 , while pawl teeth  44  are located within the gaps between gear teeth  32 , pawl teeth  46  each engage and slide over the adjacent gear tooth  32  in a similar manner. Due to the spacing and relative shape of pawl teeth  46  and gear teeth  32 , arm  42  and/or central body  38  bends or deflects upon engagement between pawl teeth  46  and gear teeth  32  during rotation in direction  24 . Once pawl teeth  46  pass over the clockwise adjacent gear tooth, the elasticity/spring action of arm  42  and/or central body  38  biases pawl teeth  44  into the space located before the next gear tooth  32 , as rotation in direction  24  continues. 
     In general, forked pawl  34  is shaped and sized such that pawl teeth  44  and  46  are not engaged with gear teeth  32  at the same time. In this arrangement, pawl teeth  44  and  46  alternatingly engage gear teeth  32  generating an alternating pattern of compression and expansion of arms  40  and  42  which moves forked pawl in an alternating or rocking motion during freewheeling rotation similar to an escapement mechanism. Specifically in this arrangement, arm  42  and pawl teeth  46  are spaced and shaped relative to pawl teeth  44  and gear teeth  32  such that pawl teeth  46  are located within gaps between adjacent gear teeth  32  when pawl teeth  44  are sliding over gear teeth  32  and such that pawl teeth  44  are located with gaps between adjacent gear teeth  32  when pawl teeth  46  are sliding over gear teeth  32  during freewheeling rotation. 
     Similarly, arm  42  and pawl teeth  46  are spaced and shaped relative to pawl teeth  44  and gear teeth  32  such that pawl teeth  46  are located within gaps between adjacent gear teeth  32  when leading surfaces of pawl teeth  44  are engaged with gear teeth  32  during engaged or driving rotation and such that pawl teeth  44  are located with gaps between adjacent gear teeth  32  when pawl teeth  46  are engaged with gear teeth  32  during engaged or driving rotation. Thus in this arrangement, when the user ceases freewheeling motion and rotates tool body  12  in the direction of arrow  26  to engage and drive a workpiece, pawl  34  is shaped such that the pawl teeth of only one of either pawl arm  40  or pawl arm  42  engage with gear teeth  32  during that driving rotation. The engagement of the arm&#39;s teeth during any particular driving rotation is based on the positioning of the pawl teeth relative to gear teeth  32  when freewheeling rotation stops such that whichever arm&#39;s teeth are closest to the adjacent clockwise facing surfaces of gear teeth  32  will be engaged during driving rotation. In this arrangement, the teeth of the pawl arm that are not engaged are generally located within the gaps between gear teeth  32  such that a space is located between the counterclockwise facing non-engagement pawl tooth surface and the adjacent clockwise facing gear tooth surface, and this results in an arrangement where the non-engaged pawl arm teeth are non-load bearing during that instance of driving rotation. 
     In addition, forked pawl  34  is shaped and sized to engage with tool body  12  in a manner that provides the support to generate the spring action during unrestricted movement. In such embodiments, base  36  has a surface  50  facing away from, and opposite from, arms  40  and  42  that engages an inner surface of tool body  12 . This engagement provides the backstop against which arms  40  and  42  are compressed during ratcheting movement. In specific embodiments, base  36  has a width, W 1 , that is greater than the width of central body  38 , and that is less than the maximum width between the lateral-most portions of arms  40  and  42 . This sizing allows for relatively narrow arms  40  and  42  and relatively narrow central body  38  to provide the spring action discussed above, while providing forked pawl  34  with stable base facilitating compression. 
     In addition, arms  40  and  42  and teeth  44  and  46  are shaped and positioned to provide both the ratcheting movement and the engaged movement of ratchet mechanism  22 , discussed herein. In particular, arms  40  and  42  are generally asymmetric about a medial or length axis  52  and form the generally y-shaped structure shown in  FIG. 3 . Teeth  44  and  46  are each positioned on arms  40  and  42 , respectively, such that teeth  44  and  46  are sloped or pointed inward toward length axis  52 . As will be discussed in more detail below, the asymmetric shape of arms  40  and  42  allows for the alternating engagement during freewheeling rotation and also ensures that the pawl teeth of only one arm  40  or  42  are engaged at one time during driving rotation. In addition, each arm  40  and  42  includes a thinned or narrowed portion  54  located between teeth  44  and  46  and central body  38 . Narrowed portions  54  are thinner than central body  38  which facilitates the flexing and spring action discussed herein. This arrangement the spring joint provided by portions  54  is located between central body  38  and pawl teeth  44  and  46  relative to a direction from the tool body  12  toward the workpiece engagement surface  20 . In contrast, typical ratchet mechanisms include a coil spring located between a tool body and a pawl body. 
     In various embodiments, the pawl mechanisms discussed herein include an n number of at least two pawl arms each bearing one or more pawl teeth, and in these embodiments, the pawl arms and/or pawl teeth on the arms have a spacing relative to each other in a manner that reduces backlash. In various embodiments, the pawl arms and/or pawl teeth on the arms have a spacing relative to each other such that maximum backlash distance (i.e., the maximum distance a leading pawl tooth must travel before engagement with a gear tooth during driving rotation, e.g., in the direction of arrow  26 ) is less than or equal to the gear tooth spacing, GTS, divided by the n number of at least two pawl arms. As used herein, GTS is the circumferential distance or angular distance between adjacent gear teeth, as shown, for example, in  FIG. 6 . This structure allows the space between adjacent gear teeth to be evenly divided by the number of pawl arms, which in turn ensures that the pawl teeth on the various arms are evenly distributed across the gaps between adjacent gear teeth, which provides the backlash reduction. As a specific example, the shape and positioning of arms  40  and  42  and/or of pawl teeth  44  and  46  on arms  40  and  42  are such that pawl teeth  44  are offset from pawl teeth  46  in the circumferential direction by distance such that backlash is less than or equal to GTS divided by 2. In one embodiment, GTS is 6 degrees and pawl  34  provides a maximum backlash of about 3 degrees (e.g., 3 degrees plus or minus 10%, 1%, etc.), and in another embodiment, GTS is 5 degrees and pawl  34  provides a maximum backlash of about 2.5 degrees (e.g., 3 degrees plus or minus 10%, 1%, etc.). 
     As will be understood as discussed above, the backlash provided by ratchet mechanism  22  can be further decreased by increasing the number of arms that pawl  34  includes and/or by decreasing the GTS of gear  30 . In one such embodiment, pawl  34  has four arms, and is formed from a stacked structure having two layers and each of the layers has two arms. In this arrangement, the teeth of each one of the four arms are positioned relative to each other (e.g., via a circumferential offset) such that the maximum backlash provided by the ratchet mechanism is GTS divided by 4. In other embodiments, pawl  34  may have 3, 4, 5, or more stacked layers each having two arms such that backlash is further decreased. 
     Further, tool body  12  includes a buttress structure  56  located adjacent to arm  42 . In the orientation of  FIG. 4 , buttress structure  56  is located clockwise from arm  42 . When tool body  12  is rotated counterclockwise (e.g., to engage the ratchet mechanism to drive a fastener), an outer, clockwise facing portion of the outer surface of arm  42  engages a counterclockwise facing surface of buttress structure  56 . Through this engagement, ratchet mechanism  22  is supported via tool body  12  during engagement with a workpiece such as a fastener. 
     Referring to  FIG. 4 , tool body  12  defines a lengthwise or medial axis  58 . In general, pawl mechanism  34  is positioned within tool body  12  such that medial axis  58  traverses, and more specifically bisects, base surface  50  of pawl mechanism  34 . In a specific embodiment, and in contrast to many compression spring based pawl mechanisms, pawl  34  is shaped such that one arm (e.g., arm  40 ) is located on one side of axis  58 , and the other arm (e.g., arm  42 ) is located on the other side of axis  58 . In addition, pawl  34  is shaped such that one arm, arm  40 , is located on one side of axis  58 , and buttress structure  56  is located on the other side of axis  58 . Applicant believes that this arrangement allows for both the use of the generally y-shaped pawl discussed herein while providing the tool body support of buttress structure  56  while also facilitating a satisfactory level of force distribution around gear  30  during driving rotation. 
     Referring to  FIGS. 5-10 , a ratchet mechanism  60  is shown according to another embodiment. Similar to ratchet mechanism  22 , ratchet mechanism  60  is supported within tool body  12  and provides both restricted movement for driving a workpiece (e.g., a fastener) and unrestricted/ratcheting movement as discussed above. In addition, similar to ratchet mechanism  22 , ratchet mechanism  60  includes a pawl arrangement having flexible elastic arms that provide spring action to the pawl rather than including a separate spring member that engages and biases the pawl. 
     Referring to  FIG. 6 , ratchet mechanism  60  includes a gear structure  62 . As shown in  FIG. 6 , gear structure  62  is a ring or annular shaped structure that includes an inner surface defining a plurality of radially inwardly extending gear teeth  64  that extend around a central open area  67 . In this arrangement, ratchet mechanism  60  and fastener engagement surfaces  20  shown in  FIG. 5  are located within and are surrounded by gear structure  62 . In this arrangement, gear structure  62  is supported by ring-shaped head portion  18  and is located within gap  66  shown in  FIG. 5 . As will be generally understood, the teeth of a pawl structure of ratchet mechanism  60  freely rotate relative to gear teeth  64  in one direction providing for ratcheting movement, and the teeth of a pawl structure of ratchet mechanism  60  engage with gear teeth  64  in the opposite direction providing for engaged or driving movement. 
     In general, gear structure  62  includes one or more connector for rigidly coupling gear structure  62  to tool body  12 . As shown in  FIG. 6 , gear structure  62  includes a projecting arm  68 . Projecting arm  68  extends radially outward from an outer surface of gear structure  62 . In general, projecting arm  68  engages a cooperating recess or surface within tool body  12  such that gear structure  62  is rigidly fixed relative to tool body  12  such that rotation of gear structure  62  relative to tool body  12  is substantially prevented. This engagement between gear structure  62  and tool body  12  allows for both driving/engaged rotation and ratcheting rotation. In the specific embodiment shown, projecting arm  68  is a generally triangular shaped structure that engages a generally triangular shaped recess within tool body  12 . In another embodiment, as shown for example in  FIG. 10 , gear teeth  64  may be formed directly on tool body  12  surrounding the pawl structure of ratchet mechanism  60 . 
     Referring to  FIGS. 7-9 , pawl structure  70  of ratchet mechanism  60  is shown and described in more detail. Pawl structure  70  includes a generally ring-shaped body  72  defining faceted (e.g., hexagonal) inner surface  71 . A hexagonal collar  73  is located within and surrounded by pawl structure  70 , and as shown in  FIG. 7 , hexagonal collar  73  defines fastener engagement surfaces  20 . In addition, collar  73  alone or combined with an outer surrounding collar, acts to hold the components of pawl structure  70  together and in proper alignment within tool body. It should be understood that collar  73  may form other shapes as may be needed to engage other, non-hexagonally shaped fasteners. 
     Pawl structure  70  includes plurality of arms  74  extending radially outward from body  72 . Each arm  74  includes a flexible arm segment  76  and a plurality of pawl teeth  78  located at the outer end (e.g., distal from the connection between body  72  and arm  74 ) of each arm  74 . A flexible spring hinge or joint  75  joins each arm  74  to pawl body  72  and is located between a radially outer section of pawl body  72  and flexible arm segment  76 . In this arrangement, spring joint  75  is in the form of a living hinge formed from material that is contiguous and continuous with both body  72  and arm  74 . In general, each arm segment  76  and/or spring hinge  75  provides flexibility sufficient for the ratcheting movement and rigidity sufficient for the driving movement as discussed herein. In specific embodiments, the elasticity/spring action of arm segment  76  and/or spring hinge  75  of pawl  70  is selected to ensure that the amount of force that needs to be applied to the tool handle/body during freewheeling/ratcheting motion is below a threshold, and in particular embodiments, the freewheeling ratcheting threshold is less than 4 lbs., specifically less than 2 lbs., and more specifically is less than 0.5 lbs. Similar to the spring joint provided by portions  54  as discussed above, spring joint  75  is located between pawl body  72  and pawl teeth  78  relative to a direction from the tool body  12  toward the workpiece engagement surface  20 . 
     In various embodiments, pawl structure  70  includes at least three arms  74 . In the specific embodiment shown, pawl structure  70  includes six arms  74 , and each arm includes three pawl teeth  78 . However, in other embodiments, pawl structure  70  includes more or less than six arms  74  and/or more or less than three pawl teeth  78  per arm. 
     As shown in the embodiment of  FIG. 8 , pawl structure  70  is formed from a stack of pawl units  80 ,  82 ,  84  and  86 . In this embodiment, each pawl unit  80 ,  82 ,  84  and  86  have the same shape and arrangement as each other. Pawl units  80 ,  82 ,  84  and  86  are arranged in a stack forming pawl structure  70 , as shown in  FIG. 8 . In some embodiments, pawl structure  70  includes two pawl units, three pawl units or more than four pawl units. It should be understood that in other embodiments, pawl structure  70  may be formed from a single, unitary piece of material that provides the functionality discussed herein. 
     As shown in  FIG. 9 , each of the pawl units  80 ,  82 ,  84  and  86  (pawl unit  80  is shown as an example) are shown and described in more detail. In specific embodiments, pawl unit  80  includes one pawl arm  74  for each side of engagement surface  20 , and in the specific embodiment shown, pawl unit  80  surrounds a hexagonally shaped, six-sided engagement surface  20  and therefore includes six pawl arms  74 . In addition, pawl arms  74  are positioned relative to engagement surfaces  20  to provide strength and load distribution during driving rotation. In specific embodiments, joints  75  are positioned adjacent to engagement surface vertices  77  which Applicant believes provides for a desirable level of load distribution. In specific embodiments, joint  75  of each arm  74  is coupled to body  72  within plus or minus 20 degrees, specifically plus or minus 10 degrees, and more specifically plus or minus 5 degrees of each vertex  77 . In specific embodiments, arms  74  and teeth  78  are sized and shaped such that the outer most tooth (e.g., the tooth at the end of each arm opposite from joint  75 ) is located adjacent to the vertex  77  and to joint  75  of the clockwise vertex or joint (in the orientation of  FIG. 9 ), and in specific embodiments, arm  74  is shaped/sized such that the outer most one of teeth  78  of each arm  74  is  72  within plus or minus 20 degrees, specifically plus or minus 10 degrees, and more specifically plus or minus 5 degrees of the adjacent, clockwise vertex  77 . In various embodiments, pawl unit  80  has a thickness, T 1 , that is selected to provide the pawl unit with a high enough strength and consistent and predictable level of compression and deformation during freewheeling and driving rotation. 
     Referring to  FIG. 10 , operation of ratchet mechanism  60  is explained in more detail. Similar to ratchet mechanism  22 , ratchet mechanism  60  is a mechanical structure that allows for free or unrestricted rotation of tool body  12  around engagement surfaces  20  in a first direction, shown as arrow  24 , and allows for restricted or driving rotation of tool body  12  around engagement surfaces  20  in a second direction  26 . When tool body  12  is rotated in the direction of arrow  24 , pawl teeth  78  slide over the counterclockwise facing surface of each gear teeth  64 , and the flexibility provided by arms  74  generally, and by flexible joint  75  specifically, allows for arms  74  to deflect inwardly as pawl teeth  78  crest the radially innermost points of pawl teeth  78 . 
     When tool body  12  is rotated in the direction of arrow  26 , the spring action flexibility provided by arms  74  generally, and by flexible joint  75  specifically, bias pawl teeth  78  into the space between adjacent gear teeth  64 . Further rotation engages clockwise facing surfaces of gear teeth  64  against counterclockwise facing surfaces of pawl teeth  78 . As will generally be understood, the relative shape and positioning of pawl teeth  78 , gear teeth  64  and arms  74  result in locking of pawl teeth  78  against gear teeth  64  (e.g., pawl teeth  78  are not permitted to slide over gear teeth  64 ) upon rotation in the direction of arrow  26 . This locking of pawl teeth  78  against gear teeth  64  allows for transfer of torque from handle  12  through ratchet mechanism  60 , engagement surfaces  20  to the workpiece (e.g., fastener) being driven by tool  10 . In the embodiment shown, multiple pawl teeth  78  at various circumferential positions around pawl structure  70  engage with gear teeth  64  upon driving rotation. This allows for forces during engaged/driving rotation to be more evenly distributed around ratchet mechanism  60  as compared to typical pawl structures. 
     Further, even force distribution is provided by a ratchet mechanism structure that distributes gear teeth  64  and/or pawl teeth  78  around fastener engagement surfaces  20 . In a specific embodiment, gear teeth  64  and/or pawl teeth  78  surround at least 180 degrees of the fastener engagement surfaces  20 . In a specific embodiment, gear teeth  64  are evenly spaced and completely surround the fastener engagement surfaces  20 . In addition, pawl teeth  78  are also positioned in evenly spaced groups surrounding fastener engagement surfaces  20 . 
     Referring to  FIGS. 11 and 12 , pawl unit  80  and a stack  120  of three pawl units,  80 ,  82  and  84 , are shown and described to illustrate various aspects of the ratchet design Applicant has determined facilitate backlash decrease and even load distribution. It should be understood that stack  120  is substantially the same as pawl stack  70  discussed above except it has three pawl units instead of four. 
     In general, as noted above, the pawl mechanisms discussed herein are sized and shaped to decrease or minimize the distance that must be traveled for the pawl teeth to engage the gear teeth upon rotation of the tool body in the driving direction. Referring to  FIG. 11 , in one embodiment, this backlash limitation is provided by slightly offsetting each of the arms  74  of pawl  80  from each other in a sequential manner around the perimeter of pawl  80 . This additional offset spacing in effect divides the gear tooth spacing by the number of arms which ensures that the maximum distance that a pawl unit must be rotated in the driving direction before one of the pawl teeth engages a gear tooth is less than GST. As a contrasting example, if arms  74  were evenly spaced around pawl  80 , the maximum distance that pawl unit could be rotated in the driving direction before a pawl tooth engages a gear tooth would be the same as the GST (see  FIG. 6  and  FIG. 10 ) of gear  62 . In specific embodiments, this offsetting distance between adjacent arm pairs is equal to GST divided by the number of pawl arms that the pawl unit has (6 in the case of pawl unit  80 ). 
     Referring specifically to  FIG. 11 , each pawl arm  74  has an angular position relative to the counterclockwise adjacent arm, starting at the 12 o&#39;clock position, shown as angles A, B, C, D, E and F. In general, one of the arms  74  can be identified as a first position arm  100  and is defined by an angle A relative to the counterclockwise adjacent arm (arm  110  in  FIG. 11 ). Second position arm  102  is positioned at an angle B from arm  100 , and angle B=A+GST/6. Third position arm  104  is positioned at an angle C from arm  102 , and angle C=B+GST/6. Fourth position arm  106  is positioned at an angle D from arm  104 , and angle D=C+GST/6. Fifth position arm  108  is positioned at an angle E from arm  106 , and angle E=D+GST/6. Sixth position arm  110  is positioned at an angle F from arm  108 , and angle F=E+GST/6. 
     Thus, given a six armed pawl mechanism, this spacing ensures that the pawl teeth of one of the arms is no more than GST divided by 6 away from engagement with the next closest gear tooth  64  when the tool handle is rotated in the driving direction, and thus, this reduces the maximum amount of backlash to GST divided 6. In various embodiments, the offset distance, represented in the 6 arm embodiment as GST/6 is less than 1.5 degrees, specifically is less than 1 degree and more specifically is between 0.5 degrees and 0.9 degrees. In specific embodiments, gear  62  includes 72 teeth, and in such embodiments, GST is 5 degrees, and GST/6 is 0.8333 degrees. In other embodiments, pawl unit  80  may include more or less than six arms, such as two arms, three arms, four arms, five arms, eight arms, etc. 
     Referring to  FIG. 12 , a stack  120  of three pawl units  80 ,  82  and  84  is shown according to an exemplary embodiment. In this embodiment, pawl units  80 ,  82  and  84  all have the same configuration as each other, and in the stacked arrangement, each pawl unit is rotationally offset from the adjacent units in the stack. In general, this rotational offset ensures that the pawl arms with a given position (e.g., pawl arm  100  at angle A) are evenly distributed around the circumference of stack  120 . As will be understood, given a particular position of pawl stack  120  relative to gear teeth  64 , one of the arms  100 ,  102 ,  104 ,  106 ,  108  and  110  will be a leading arm (i.e., the pawl arm closest to engagement with a gear tooth when rotation in the driving direction begins, which can be any one of the pawl arms depending on the position when freewheeling motion is stopped) due to the offset position of that arm. By distributing the leading arm around the circumference of stack  120 , the pawl teeth that engage with gear teeth  64  upon engagement when the tool body is rotated in the driving direction is also evenly distributed around stack  120  and gear  62 . Applicant believes this force/load distribution limits the risk of wear, breakage, etc. by distributing the load during fastener driving. 
     Referring specifically to  FIG. 12 , the rotational position between pawl units  80 ,  82  and  84  is shown in more detail. As shown, each of pawl units  80 ,  82  and  84  are rotationally offset from each other by 120 degrees, such that each of the distinctly positioned pawl arms are offset from the corresponding arm in the adjacent unit in the stack by 120 degrees. Thus, as show in  FIG. 12  as an example, pawl arms  100  (shown at the 12 o&#39;clock position in the orientation of  FIG. 11 ) of each pawl unit  80 ,  82  and  84  are spaced at 120 degrees from each other in the circumferential direction. As will be understood the rotational offset between pawl units within the stack is based on the number of units in the stack as determined by the equation 360 degrees divided by the number of pawl units in the stack. For example, the four pawl unit stack  70  shown in  FIG. 8  has a 90 degree rotational offset between adjacent units in the stack. 
     Referring to  FIGS. 12 and 13 , in various embodiments, pawl units include an alignment feature to facilitate alignment of the pawl units in a manner that generates the rotational offset discussed above. In one embodiment, each pawl unit includes a recess  122  on one major surface and a projection  124  on the opposite major surface. The recess  122  and projection  124  are positioned such that as pawl units are stacked, recess  122  of one pawl unit receives the projection  124  of the adjacent pawl unit such that the desired rotational offset position is achieved, as discussed above. 
     It should be understood that the figures illustrate the exemplary embodiments in detail, and it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention. 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more component or element, and is not intended to be construed as meaning only one. 
     Various embodiments of the invention relate to any combination of any of the features, and any such combination of features may be claimed in this or future applications. Any of the features, elements, or components of any of the exemplary embodiments discussed above may be utilized alone or in combination with any of the features, elements, or components of any of the other embodiments discussed above. 
     In various exemplary embodiments, the relative dimensions, including angles, lengths and radii, as shown in the Figures are to scale. Actual measurements of the Figures will disclose relative dimensions, angles and proportions of the various exemplary embodiments. Various exemplary embodiments extend to various ranges around the absolute and relative dimensions, angles and proportions that may be determined from the Figures. Various exemplary embodiments include any combination of one or more relative dimensions or angles that may be determined from the Figures. Further, actual dimensions not expressly set out in this description can be determined by using the ratios of dimensions measured in the Figures in combination with the express dimensions set out in this description. In addition, in various embodiments, the present disclosure extends to a variety of ranges (e.g., plus or minus 30%, 20%, or 10%) around any of the absolute or relative dimensions disclosed herein or determinable from the Figures.