Patent Publication Number: US-6981434-B2

Title: Reinforcement structure for wrench head

Description:
FIELD OF THE INVENTION 
   This is a Continuation-In-Part application of applicant&#39;s former patent application Ser. No. 10/428,114, filed on May 2, 2003, now U.S. Pat. No. 6,857,339. 

   BACKGROUND OF THE INVENTION 
   Applicant&#39;s former U.S. Pat. No. 6,691,594 discloses a wrench wherein the pawls each have a protrusion on a top thereof and when installing the pawls into the recess defined in communication with the through hole in the head, the pawls have to be tilted such that the protrusions can be inserted in the recess first and then the two respective bodies of the pawls are rotated to be inserted in the recess. This spends too much assembly time. Some manufacturers break the portion between the through hole for receiving the engaging wheel and the recessed area for receiving the control member, such that the pawls can be inserted in the recess for the pawls directly without any angle adjustment. Nevertheless, the broken space weakens the structural strength of the head of the wrench. 
   U.S. Pat. Nos. 6,575,060 and 6,279,428 respectively disclose a wrench wherein the pawl includes a curve surface and the control member drives the center of the curve surface directly. As shown in  FIG. 9  which discloses the structure of U.S. Pat. Nos. 6,282,991 and 6,282,992. The head  91  of the wrench  90  has a first hole  910  for receiving an engaging wheel  94  therein and a second hole  95  is defined between and in communication with the first hole  910  and a third hole  93  which receives a control member  92  therein. A pawl  96  is received in the second hole  95  and is engaged with the engaging wheel  94 . a driving piece  97  has one end received int eh control member  92  and the other end of the driving piece  97  is engaged with a recess defined in the pawl  96 . The pawl  96  is shifted left and right so that the distal end of the second hole  95  is in a broken state with the third hole  93 , and the curve inside of the second hole  93  supports the pawl  96 . The curve inside cannot provide sufficient support to the pawl  96 . 
   The present invention intends to provide a wrench wherein a yield space is defined in an underside of the bridge portion located between the through hole for receiving the engaging wheel in the head and a recessed area for receiving the control member such that the protrusions of the pawls can be installed directly without any adjustment and the structural strength of the head of the wrench is reinforced. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a wrench which comprises a head having a through hole for receiving an engaging wheel and a recess for receiving two pawls is defined in an inner periphery of the through hole. A recessed area is defined in a surface of the head and a bridge portion is located between the through hole and the recessed area. A space is defined in an underside of the bridge portion and in communication with the through hole. A spring is connected between the two pawls and each pawl has a protrusion which extends into the recessed area. A control member is rotatably received in the recessed area and has a concavity in which the two protrusions are retained. 
   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 wrench of the present invention; 
       FIG. 2  is a perspective view to show the wrench of the present invention; 
       FIG. 3  is a perspective view to show the two pawls received in the recess; 
       FIG. 4  is a top cross sectional view to show the wrench of the present invention; 
       FIG. 5  is a side cross sectional view to show the wrench of the present invention; 
       FIGS. 6 and 7  show two positions of the pawls controlled by the control member; 
       FIG. 8  is an exploded view to show another embodiment of the wrench of the present invention, and 
       FIG. 9  is a side cross sectional view to show a conventional wrench. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 to 5 , the wrench  10  of the present invention comprises a head  11  having a through hole  12  defined therethrough and a recess  14  is defined in an inner periphery of the through hole  12 . An engaging wheel  20  with outer teethed surface  201  is rotatably received in the through hole  12  and positioned by a C-clip  21  cooperated with a ring  22 . 
   A recessed area  13  is defined in a surface of the head  11  and a bridge portion  16  is located between the through hole  12  and the recessed area  13 . The bridge portion  16  is made to be thinner so as to have a space  17  defined in an underside of the bridge portion  16  and in communication with the through hole  12  and the recess  14 . A central hole  130  is defined through the recessed area  13 . Two pawls  30  are movably received in the recess  14  and a spring  31  is connected between two respective holes  302  defined in two facing ends of the two pawls  30 . The two pawls  30  each have a protrusion  303  on a top thereof and the two protrusions  303  extend into the recessed area  13  via an opening  15  that is a part of the space  17  and defined through the recessed area  13 . The two pawls  30  have a toothed side  301  which is alternatively engaged with the outer teethed surface  201  of the engaging wheel  20 . 
   Further referring to  FIGS. 6 and 7 , a control member  40  rotatably received in the recessed area  13  and includes a disk  41  which has a positioning hole  410  so that a bolt  43  extends through the central hole  130  and the positioning hole  410 . A recess  131  is defined in a top of the inside of the recessed area  13  and a bead  45  and a spring  44  are received in the recess  131 . The bead  45  is engaged with one of two dents  411  defined in an underside of the disk  41  so that the user can position the disk  40  at two positions defined by the two dents  411 . A concavity  412  is defined in a periphery thereof so as to retain the two protrusions  303  so that when the user shifts a lever  42  on the disk  41 , the two pawls  30  are moved in the recess  14  and engaged with the engaging wheel  20 . 
   Because of the space  17 , when installing the pawls  30  into the recess  14 , the pawls  30  need not to tilt and the protrusions  303  are allowed to pass through the space  17  and the pawls  30  are conveniently installed in the recess  14 . 
   As shown in  FIG. 8 , the invention can also used in a ratchet wrench that has a driving shaft  200  integrally extending from the engaging wheel  20 A. The difference from the embodiment as disclosed in  FIGS. 1–5  is that the control member  40 A includes a rod  46  extending from an underside of the disk  41 A and a retaining member  47  is mounted to the rod  46  after the rod  46  extends through the central hole  130  in the recessed area  13  so as to position the control member  40 A. 
   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.