Abstract:
A ratchet wrench includes a wrench body, a ratchet wheel, a pawl member, a control member, a direction control member, and a locking plate. Thus, the pawl member engages the ratchet wheel rigidly and closely, so that the pawl member and the ratchet wheel have the optimum locking state.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a ratchet wrench, and more particularly to a ratchet wrench having the optimum locking state. 
   2. Description of the Related Art 
   A conventional ratchet wrench in accordance with the prior art comprises a wrench body, a ratchet wheel rotatably mounted in the wrench body, and a locking pawl pivotally mounted in the wrench body and engaged with the ratchet wheel. In operation, a workpiece, such as a screw member, is mounted in the ratchet wheel, so that the ratchet wheel can be used to rotate the workpiece by rotation of the wrench body. 
   However, only one side of the locking pawl is engaged with the ratchet wheel and the other side of the locking pawl is not in contact with the ratchet wheel, so that the locking pawl does not engage the ratchet wheel rigidly and closely. Thus, the locking pawl and the ratchet wheel do not form the optimum locking state. 
   The closest prior art of which the applicant is aware is disclosed in his U.S. Pat. No. 6,516,690. 
   SUMMARY OF THE INVENTION 
   The present invention is to mitigate and/or obviate the disadvantage of the conventional ratchet wrench. 
   The primary objective of the present invention is to provide a ratchet wrench, wherein the pawl member engages the ratchet wheel rigidly and closely, so that the pawl member and the ratchet wheel have the optimum locking state. 
   Another objective of the present invention is to provide a ratchet wrench, wherein the peripheral face of the control member is tangent to the arcuate concave face of the pawl member, so that when the control member is rested on the pawl member, the control member and the pawl member form a linear contact face, and the control member can be locked on and detached from the pawl member easily and conveniently. 
   In accordance with the present invention, there is provided a ratchet wrench, comprising a wrench body, a ratchet wheel, a pawl member, and a control member, wherein:
         the wrench body has an end formed with a receiving hole having a side formed with a receiving recess and a control recess located beside the receiving recess;   the ratchet wheel is rotatably mounted in the receiving hole of the wrench body;   the pawl member is pivotally mounted in the receiving recess of the wrench body and has a first side engaged with the ratchet wheel and a second side formed with an arcuate concave face;   the control member is rotatably mounted in the control recess of the wrench body to control movement of the pawl member in the receiving recess of the wrench body;   the control member has a peripheral face rested on the arcuate concave face of the pawl member; and   the control member drives the pawl member to press a side face of the receiving recess of the wrench body and to engage the ratchet wheel.       

   Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of the ratchet wrench in accordance with the first embodiment of the present invention; 
       FIG. 1A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 2  is a partially perspective assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 2A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 2 ; 
       FIG. 3  is a partially cut-away perspective assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 4  is a top plan assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 4A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 4 ; 
       FIG. 5  is a top plan assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 5A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 5 ; 
       FIG. 6  is a partially perspective assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 6A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 6 ; 
       FIG. 7  is a top plan assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 7A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 7 ; 
       FIG. 8  is a top plan assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 8A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 8 ; 
       FIG. 9  is an exploded perspective view of the ratchet wrench in accordance with the second embodiment of the present invention; 
       FIG. 10  is a partially perspective assembly view of the ratchet wrench as shown in  FIG. 9 ; and 
       FIG. 10A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 10 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings and initially to  FIGS. 1–3 , a ratchet wrench in accordance with a first embodiment of the present invention comprises a wrench body  10 , a ratchet wheel  20 , a pawl member  30 , a control member  40 , a direction control member  70 , and a locking plate  80 . 
   The wrench body  10  has an end formed with a receiving hole  11 . The receiving hole  11  of the wrench body  10  has a bottom formed with a snap groove  14  and has a side formed with a receiving recess  12  and a control recess  13  located beside the receiving recess  12 . The control recess  13  of the wrench body  10  communicates with the receiving recess  12  of the wrench body  10 . 
   The ratchet wheel  20  is rotatably mounted in the receiving hole  11  of the wrench body  10 . The ratchet wheel  20  has an inner wall formed with a polygonal recess  21  and an outer wall provided with a plurality of ratchet teeth  22 . 
   The pawl member  30  is pivotally mounted in the receiving recess  12  of the wrench body  10 . The pawl member  30  has a first side provided with a plurality of locking teeth  31  meshing with the ratchet teeth  22  of the ratchet wheel  20  and a second side formed with an arcuate concave face  32 . 
   The control member  40  is rotatably mounted in the control recess  13  of the wrench body  10  to control movement of the pawl member  30  in the receiving recess  12  of the wrench body  10 . The control member  40  has a peripheral face rested on the arcuate concave face  32  of the pawl member  30 . The control member  40  has an upper end formed with two abutting faces  42  (see  FIG. 1A ) and two concave portions  43  each aligning with a respective one of the two abutting faces  42 . The control member  40  has a top formed with a polygonal protruding stud  44 . The control member  40  is formed with a receiving chamber  41 . 
   The ratchet wrench further comprises an urging cap  50  movably mounted in the receiving chamber  41  of the control member  40  and urged on the arcuate concave face  32  of the pawl member  30  to force the pawl member  30  to engage the ratchet wheel  20 . 
   The ratchet wrench further comprises an elastic member  51  mounted in the receiving chamber  41  of the control member  40  and urged on the urging cap  50  to move the urging cap  50  toward the arcuate concave face  32  of the pawl member  30 . 
   The direction control member  70  is rotatably mounted on the wrench body  10  and secured on the top of the control member  40  for rotating the control member  40 . The direction control member  70  has a bottom formed with a polygonal recess  71  for securing the protruding stud  44  of the control member  40 . 
   The locking plate  80  made of an elastic material is secured in the receiving recess  12  of the wrench body  10  and locked between the direction control member  70  and the control member  40 . The locking plate  80  has a side formed with an abutting edge  81  (see  FIG. 2A ) rested on one of the two abutting faces  42  of the control member  40 . The locking plate  80  is provided with a convex portion  82  (see  FIG. 2A ) secured in the respective concave portion  43  of the control member  40 . 
   The ratchet wrench further comprises a bottom cover  90  secured in the receiving recess  12  of the wrench body  10  and rested on a bottom of the ratchet wheel  20 . 
   The ratchet wrench further comprises a snap ring  91  secured in the snap groove  14  of the wrench body  10  and rested on a bottom of the bottom cover  90 . 
   In assembly, the control member  40  is placed in the control recess  13  of the wrench body  10 . Then, the locking plate  80  is secured in the receiving recess  12  of the wrench body  10 , with the abutting edge  81  of the locking plate  80  being rested on the respective abutting face  42  of the control member  40  to prevent the control member  40  from detaching from the control recess  13  of the wrench body  10 . At this time, the convex portion  82  of the locking plate  80  is secured in the respective concave portion  43  of the control member  40 . Then, the urging cap  50  and the elastic member  51  are mounted in the receiving chamber  41  of the control member  40  to form a sub-assembly as shown in FIG.  2 . Then, the pawl member  30 , the ratchet wheel  20 , the bottom cover  90 , the snap ring  91  and the direction control member  70  are in turn mounted on the wrench body  10 , thereby forming the ratchet wrench as shown in  FIG. 3 . 
   Referring to  FIGS. 4 and 4A  with reference to  FIGS. 1 and 2 , the direction control member  70  is rotated in a first direction to rotate the control member  40  until one concave portion  43  of the control member  40  is positioned on the convex portion  82  of the locking plate  80 , so that the control member  40  is positioned on the locking plate  80 . At the same time, one abutting face  42  of the control member  40  is locked with the abutting edge  81  of the locking plate  80  during rotation of the control member  40  so as to control the maximum rotation angle of the control member  40 , thereby preventing the urging cap  50  from hitting the side face of the receiving recess  12  of the wrench body  10 . At this time, the urging cap  50  drives the pawl member  30  to press a side face of the receiving recess  12  of the wrench body  10  and to engage the ratchet wheel  20 , so that the ratchet wheel  20  can be driven by the wrench body  10  to rotate clockwise as shown in  FIG. 4 . 
   Referring to  FIGS. 5 and 5A  with reference to  FIGS. 1 and 2 , the urging cap  50  is rested on a first side of the arcuate concave face  32  of the pawl member  30  to drive the pawl member  30  to press a side face of the receiving recess  12  of the wrench body  10  and to engage the ratchet wheel  20 , and the control member  40  has a peripheral face rested on a second side of the arcuate concave face  32  of the pawl member  30 , so that the pawl member  30  engages the ratchet wheel  20  rigidly and closely. Preferably, the peripheral face of the control member  40  has a cylindrical shape. In addition, the peripheral face of the control member  40  is tangent to the second side of the arcuate concave face  32  of the pawl member  30 , so that when the control member  40  is rested on the pawl member  30 , the control member  40  and the pawl member  30  form a linear contact face. Thus, the control member  40  is locked on and detached from the pawl member  30  easily and conveniently. 
   Referring to  FIGS. 6 ,  6 A,  7  and  7 A with reference to  FIGS. 1 and 2 , the direction control member  70  is rotated in a second direction to rotate the control member  40  until the other concave portion  43  of the control member  40  is positioned on the convex portion  82  of the locking plate  80 , so that the control member  40  is positioned on the locking plate  80 . At the same time, the other abutting face  42  of the control member  40  is locked with the abutting edge  81  of the locking plate  80  during rotation of the control member  40  so as to control the maximum rotation angle of the control member  40 , thereby preventing the urging cap  50  from hitting the side face of the receiving recess  12  of the wrench body  10 . At this time, the urging cap  50  drives the pawl member  30  to press a side face of the receiving recess  12  of the wrench body  10  and to engage the ratchet wheel  20 , so that the ratchet wheel  20  can be driven by the wrench body  10  to rotate counterclockwise as shown in  FIG. 7 . 
   Referring to  FIGS. 8 and 8A  with reference to  FIGS. 1 and 2 , the urging cap  50  is rested on the second side of the arcuate concave face  32  of the pawl member  30  to drive the pawl member  30  to press a side face of the receiving recess  12  of the wrench body  10  and to engage the ratchet wheel  20 , and the control member  40  has a peripheral face rested on the first side of the arcuate concave face  32  of the pawl member  30 , so that the pawl member  30  engages the ratchet wheel  20  rigidly and closely. In addition, the peripheral face of the control member  40  is tangent to the first side of the arcuate concave face  32  of the pawl member  30 , so that when the control member  40  is rested on the pawl member  30 , the control member  40  and the pawl member  30  form a linear contact face. Thus, the control member  40  is locked on and detached from the pawl member  30  easily and conveniently. 
   Referring to  FIGS. 9 ,  10  and  10 A, the ratchet wrench in accordance with the second embodiment of the present invention is shown, wherein the control member  40  has a bottom formed with two concave portions  43 , and the convex portion  82  of the locking plate  80  is undefined. The ratchet wrench further comprises an elastic plate  60  secured in the receiving recess  12  of the wrench body  10  and provided with a convex portion  61  positioned in one of the two concave portions  43  of the control member  40 . 
   Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.