Patent Publication Number: US-6907804-B2

Title: Pawl switch member for ratchet tools

Description:
This is a Continuation-In-Part application of applicant&#39;s former patent application with the application Ser. No. 10/104,529, filed on Mar. 25, 2002 now abandoned. 

   BACKGROUND OF THE INVENTION 
   Field of the Invention 
   A conventional ratchet tool generally includes a head with a ratchet mechanism received therein and a handle connected to the head. The ratchet mechanism includes a toothed engaging member and a pawl is engaged with the teeth of the toothed engaging member. The pawl is controlled by a pawl shifting member which generally extends from the top surface of the head and the pawl shifting member limits the head of the tool from inserting into a recess to reach a bolt or an object to be tightened or loosened. 
   Besides, the pawl shifting member is applied a force that comes from the pawl when the teeth of the pawl move over the teeth of the toothed engaging member during rotating the handle of the tool. The force slightly moves the pawl shifting member away from the head of the tool and the movement gives a quality of assembly issue to the users. In other words, the pawl shifting member is not well positioned during the rotating the handle while the engaging member is stationary relative to the head of the tool. 
   SUMMARY OF THE INVENTION 
   In accordance with one aspect of the present invention, there is provided a ratchet tool which comprises a handle and a head which has a through hole for receiving a driving member therein and a recess is defined in an inner periphery of the through hole. A first hole is defined in an inner periphery of the recess for receiving a first spring and a first bead therein. A first concavity is defined in one of two sides of the head and communicates with the recess so as to receive a pawl shifting member therein. A second concavity is defined in a throat portion connected between the handle and the head so as to receive a pawl shifting member therein. The pawl has a protrusion extending from an end surface thereof and the pawl shifting member has recessed area defined in an underside thereof so as to accommodate the protrusion of the pawl. A lever extends from the pawl shifting member and is movably engaged with the second concavity. A second hole is defined in a top of the pawl shifting member and a second spring and a second bead are received in the second hole. 
   A cap is engaged with a groove defined in the inner periphery of the through hole in the head and has a hole so that an end of the driving member is engaged with the hole in the cap. An extension extends outward from the cap and includes two positioning recesses so that the second bead is engaged in one of the two positioning recesses. 
   The primary object of the present invention is to provide a ratchet tool wherein the pawl switch member is well positioned during operation and is not moved by the pawl during rotation of the handle. 
   The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view to show the ratchet tool of the present invention; 
       FIG. 2  is a top view to show the arrangement of the driving member, the pawl and the pawl switch member of the ratchet tool of the present invention; 
       FIG. 2-1  shows an enlarged view of the second bead being engaged with one of the two positioning recesses in the cap; 
       FIG. 3  shows the second bead is shifted to the other one of the two positioning recesses in the cap; 
       FIG. 3-1  shows an enlarged view of the second bead being engaged with the other one of the two positioning recesses in the cap, and 
       FIG. 4  is a side cross sectional view to show the ratchet tool of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 ,  2 - 1 , and  4 , the ratchet tool of the present invention comprises a handle and a head  1  which has a through hole  10  defined therethrough so that a driving member  3  is engaged with the through hole  10 , and a recess  11  is defined in an inner periphery of the through hole  10  so that a pawl  4  is movably received in the recess  11 . The driving member  3  has first teeth  31  defined in an outer periphery thereof and has a polygonal inner periphery  30  such that a nut for example can be clamped by the polygonal inner periphery  30 . 
   A first hole  110  is defined in an inner periphery of the recess  11  and a first spring  60  and a first bead  61  are received in the first hole  110 . The pawl  4  has second teeth  40  defined in a first side thereof so as to be engaged with the first teeth  31  of the driving member  3 . The first bead  61  contacts a second side of the pawl  4 . An elongate protrusion  41  extends from an end surface of the pawl  4 . 
   A first concavity  12  is defined in one of two sides of the head  1  and communicates with the recess  11 , and a second concavity  13  is defined in a throat portion connected between the handle and the head  1 . The second concavity  13  communicates with the first concavity  12 . The first concavity  12  and the second concavity  13  are located in two different horizontal planes. 
   A pawl shifting member  5  is rotatably received in the first concavity  12  and has a recessed area  50  defined in an underside thereof so as to accommodate the protrusion  41  of the pawl  4 . A lever  51  extends from the pawl shifting member  5  and is movably engaged with the second concavity  13 . A second hole  52  is defined in a top of the pawl shifting member  5  and a second spring  62  and a second bead  63  are received in the second hole  52 . 
   There is a shoulder portion  14  extends from the inner periphery of the through hole  10  in the head  1  and a retaining member  7  is rested on the shoulder portion  14  and encloses an annular flange extending from an end of the driving member  3 . The retaining member  7  is engaged with the a groove  15  defined in the inner periphery of the through hole  10  in the head  1 . A cap  2  has a hole  20  defined therethrough so that the annular flange of the driving member  3  is engaged with the hole  20  in the cap  2 . A groove  21  is defined in an outer periphery of the cap  2  so that an inner periphery of the retaining member  7  is engaged with the groove  21  to position the cap  2 . An extension extends outward from the cap  2  and covers on the pawl shifting member  5 . Two positioning recesses  22  are defined in an underside of the extension of the cap  2  so that the second bead  63  is engaged in one of the two positioning recesses  22 . 
   It is to be noted that the top of the pawl shifting member  5  is a flat surface which is in flush with the side of the head  1  so that no extra protrusion protrudes from the side of the head  1  and this allows the head  1  of the ratchet tool to be inserted in a narrow space. 
   When the second bead  63  is engaged with one of the two positioning recesses  22  as shown in  FIG. 2-1 , this position means that the lever  51  is pushed upward in the drawing and the remote end  43  contacts the inner periphery of the recess  11 . When rotating the handle counter clockwise, the driving member  3  is co-rotated with the handle, and the nut (not shown) clamped by the driving member  3  is loosened or tightened. 
   As shown in FIGS.  3  and  3 - 1 , when shifting the lever  51  downward in the drawing, the second bead  63  is moved to the other positioning recess  22 . When rotating the handle counter clockwise, the second teeth  40  of the pawl  4  move over the first teeth  31  of the driving member  3  while the driving member  3  is remained still. The pawl shifting member  5  is well positioning by the engagement of the second bead  63  and the positioning recesses  22  so that the pawl shifting member  5  will not move during operation by the pawl  4 . 
   While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.