Abstract:
An assembly or reset gear device, typically used with ratchet wrenches, that has a body and at least two pawls pivotally attached to it and another part that has teeth that engage with the second pawl&#39;s teeth. The device that acts as an anvil has one body that is fixed to the head of a ratchet tool, while a second body can selectively rotate within the head. The second body also has two pawls, the second of which can selectively engage with the fixed first body. A pneumatic ratchet tool that employs such a device and a method of using the same is also disclosed.

Description:
BACKGROUND OF INVENTION  
       [0001]     1. Technical Field  
         [0002]     This invention relates generally to the field of ratchet wrenches. More particularly, this invention provides for a reset gear that improves the reliability of various ratchet tools, such as pneumatic ratchet wrenches.  
         [0003]     2. Related Art  
         [0004]     In the field of pneumatic ratchet wrenches, as with tools, in general, greater reliability with the tool is desirous.  
         [0005]     For example, it is desirable to have pneumatic ratchet wrenches without excessive slipping of the ratchet head, which frequently is due to worn out springs in the ratchet head. In order to fix the broken, or inefficient, wrench, the springs are typically replaced in the head. Alternatively, the existing ratchet head is replaced with an entirely new ratchet head. In either event, cost and time is expended in maintaining and/or fixing, the wrench.  
         [0006]     Accordingly, there is a need in the field of ratchet wrenches, including pneumatic ratchet wrenches, for an improved ratchet head design.  
       SUMMARY OF INVENTION  
       [0007]     The present invention provides an apparatus for use with a ratchet wrench that offers improved reliability.  
         [0008]     A first general aspect of the invention provides an anvil assembly, said assembly comprising: 
        a body, having a first pawl and a second pawl, each said first pawl and said second pawl pivotally mounted thereon; and     an element attached to said body, said element includes a plurality of teeth for engagement with a plurality of teeth on said second pawl.        
 
         [0011]     A second general aspect of the invention provides an anvil device for use in a head of a ratchet tool, said device comprising: 
        a first body, fixedly attachable to said head;     a second body, configured to selectively rotate within said head, said second body further comprising a first pawl and a second pawl, wherein said second pawl is configured to selectively engage with said first body.        
 
         [0014]     A third general aspect of the invention provides a pneumatic ratchet tool, said tool comprising: 
        a housing;     a motor, mounted within said housing;     a ratchet head, extending from said housing;     a first pawl, operatively attached within said ratchet head for engaging a first ratchet; and     a second pawl, operatively attached within said ratchet head for engaging with a second ratchet, wherein said motor is operatively attached to said first pawl and said second pawl.        
 
         [0020]     A fourth general aspect of the invention provides a method comprising: 
        providing a body;     pivotally attaching a first pawl and a second pawl to said body; and     attaching an element to said body, said element includes a plurality of teeth for engagement with a plurality of teeth on said second pawl.        
 
         [0024]     The foregoing and other features of the invention will be apparent from the following more particular description of various embodiments of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     Some of the embodiments of this invention will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:  
         [0026]      FIG. 1  depicts a top, perspective view of an embodiment of an anvil, in accordance with the present invention;  
         [0027]      FIG. 2  depicts a top, perspective view of an embodiment of an anvil with a reset gear cover removed, in accordance with the present invention;  
         [0028]      FIG. 3  depicts an exploded, top, perspective view of an embodiment of an anvil, in accordance with the present invention;  
         [0029]      FIG. 4  depicts an exploded, top, perspective view of an anvil and a front portion of a pneumatic ratchet wrench, in accordance with the present invention; and  
         [0030]      FIG. 5  depicts a side, elevation view of a pneumatic ratchet wrench, in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]     Although certain embodiments of the present invention will be shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present invention will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of an embodiment. The features and advantages of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings.  
         [0032]     As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.  
         [0033]     Referring to the drawings,  FIG. 1  depicts one embodiment of an anvil assembly, hereinafter designated  10 . The assembly, or device,  10  includes a plurality of parts including a first pawl  20  and a second pawl  30  (see e.g.,  FIG. 2 ). Each of the first and second pawls  20 ,  30  include a plurality of teeth  21 ,  31 . The pawls  20 ,  30  are situated on, or within, a ratchet anvil body  12 . At a first end of the body  12  is an anvil drive end  15 . The drive end  15  may be any suitable shape and configuration to adapt to a workpiece (not shown) or receive a driving device (not shown) such as a socket, tool bit, screwdriver, and the like. At the second end of the body  12 , opposite to the drive end  15  is an actuator  16 , similarly with a plurality of teeth  17 . A shift linkage  112  (See  FIG. 5 ) engages with the teeth  17  of the actuator  16  in order to switch the direction of rotation of the anvil  12 . Further located on the anvil body  12  is a gear cover  40 , which covers the second pawl  30  ( FIG. 2 ). The gear cover  40  has a hexagonally-shaped outer circumference. This shape allows the gear cover  40  to mate with a matching hexagonal shape recess (not shown) on a ratchet housing  100  (See e.g.,  FIG. 4 ) so that the gear cover  40  remains fixed and does not rotate along with the anvil body  12 .  
         [0034]     Alternatively, there are other embodiments that will allow the gear cover  40  to not rotate with the anvil body  12 . For example, the gear cover  40  may have an appendage, or extension (not shown), that allows the gear cover  40  to be fixed to a portion of the ratchet housing  100  ( FIG. 4 ) so that the gear cover  40  remains fixed and does not rotate with the anvil body  12 . The appendage mates with a corresponding recess, hole, slot, or the like, on or within the ratchet housing  100 . In still another embodiment (not shown), teeth  42  ( FIG. 3 ) of the gear cover  40  can be integrated directly into the ratchet housing  100  itself, thereby rendering the gear cover  40  superfluous. The teeth  42 , thus, provide a second ratchet to the invention. A first ratchet will be discussed below.  
         [0035]      FIG. 2  shows the same view as in  FIG. 1 , yet with the reset gear cover  40  removed. In  FIG. 2 , one can readily see that the second pawl  30  is located so the teeth  31  can engage with the teeth  42  (See  FIG. 3 ) on the internal surface of the reset gear cover  40  (i.e., the second ratchet). The second pawl  30  is rotatably attached to the anvil body  12  via a second pivot pin  35 .  
         [0036]     Finally,  FIG. 3  most clearly shows an exploded view of the entire assembly  10 . The assembly  10  includes an anvil body  12  that has an axial opening  13  in which resides the actuator  16 . The axial opening  13  is coaxial with the aforementioned drive end  15 . Rotatably attached to the anvil body  12  via a pin  25  resides the first pawl  20 . The first pawl  20  resides within a recess in the anvil body  12 . A first spring  23  and lock pin  22  allow the first pawl  20  to engage, via teeth  21 , against teeth on the inside of a ratchet yoke  104  ( FIG. 4 ), as is standard in the art. That is the teeth on the inside of the yoke  104  form the, aforementioned, first ratchet. The spring  23  provides a bias so that the pawl  20  stays engaged against the ratchet yoke  102  thereby preventing any slipping, or back (or “second” direction) rotation of the anvil  10 , during rotation in a forward (or “first” direction) rotation. Depending on the direction of the rotation of the anvil body  12 , the teeth  21  engage against the ratchet yoke  103  and prevent back rotation of the anvil body  12 .  
         [0037]     The anvil body  12  has a second pawl  30  that resides within a second recess on the anvil body  12 . The second pawl  30  includes teeth  31 . The second pawl  30  is rotatably attached, via a pin  35 , to the anvil body  12 . Further a lock pin  32  and spring  33  provide bias to the second pawl  30 . The teeth  31  of the second pawl  30  engage and bear against the teeth  42  located on the reset gear cover  40 . The reset gear cover  30  may rest upon a surface  14  of the anvil body  12 . The first spring  23  and lock pin  22  of the first pawl  20  and the second spring  33  and locking pin  32  of the second pawl  30  may be opposed, as seen in  FIG. 3 .  
         [0038]     An advantage of the second pawl  30  is that it provides additional anti-slipping capability to the assembly  10 . This anti-slipping aspect is a further advantage when additional extension(s) and/or torsion/torque bars (not shown) are amended to the drive end  15  of the anvil  10 . A disadvantage of adding these various extension(s) is that they may act as a type of torsion spring that may overcome the spring force of any springs providing locking bias to a pawl. Thus, frequently, when one adds an extension(s), a slipping occurs because the torsion, or spring, force of the extension(s) overcomes and exceeds the spring force of the pawl spring. This invention overcomes this shortcoming, amongst others. In part because the teeth  42  and cover  40  of the assembly  10  are fixed to the ratchet head, or ratchet housing  100  ( FIG. 4 ), the invention provides enhanced and improved anti-slip capability. The teeth  31  of the second pawl  30  more positively engage with, or obtain purchase against, the teeth  42  of the cover  40 . Thus, during rotation of the anvil assembly  10 , the possibility of any of the aforementioned “back” slipping, or back rotation, is mitigated, or entirely removed.  
         [0039]     Turning now to  FIGS. 4 and 5 , which show one embodiment of how the assembly  10  may be incorporated into a ratchet tool, in this case a pneumatic ratchet wrench  200 . Note that, although the embodiments shown depict a pneumatic tool, the invention clearly can be utilized with other types of power tools (e.g., electric, etc.), as well as, hand (i.e., non-powered) ratchet tools.  
         [0040]     A ratchet housing  100  that includes a clamp nut  102  for attachment to a tool housing  105  with a motor  106  therein also housing the anvil assembly  10  and a ratchet yoke  104  such as those known in the art. The teeth  21  of the first pawl  20  engage with the teeth on the ratchet yoke  104 . The tool  200  further includes a trigger  108  that operates the motor  106 . The housing  105  further includes a connection port  109  for fluid connection with a pressurized fluid source (not shown). A cover  110  is shown removed that covers and protects the actuator  16  and shift linkage  112  that is in communication with a manual forward reverse switch  113 .  
         [0041]     In general terms, the wrench  200  converts the flow and pressure of fluid (e.g., air) from an air source (not shown) in fluid communication with the connection port  109  to rotational energy at the anvil  12 . The wrench  200  being employed to rotate workpieces (not shown) via the anvil  12 , or an attachment (not shown) attached to the drive end  15  of the anvil  12 .  
         [0042]     While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.