Abstract:
A ratchet wrench mainly includes a main body installed with a driving gear and a driven gear respectively having teeth formed spirally and engaged with each other. A confining chamber in the main body has an inner wall formed with ratchet teeth able to restrictively lock with ratchet teeth formed on the teeth of the driven gear. An interactive member is installed in an insert hole of the driven gear, with one end connected with the orientating member and another end positioned on the cover. A pressing piece is fixed on the interactive member, confined in the insert hole of the driven gear. A spring is located between the pressing piece and the driven gear. By switching the orientating member, the driving gear can easily change rotating direction, with a strong locking effect.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a ratchet wrench, particularly to one facilitating to alter a rotation direction of a driving gear by change-over of an orientating member, able to achieve excellent efficacy of engagement and braking of the driving gear. In addition, it can stabilize transmission when the ratchet wrench works. 
     2. Description of the Prior Art 
     Generally, a ratchet wrench cooperating with different sleeves is employed for locking and detaching different kinds of bolts or nuts. A conventional ratchet wrench  1 , as shown in  FIG. 1 , includes a main body  10  formed with an accommodating groove  100  and a receiving groove  101 , the accommodating groove  100  bored with a through hole  102 , and the receiving groove  101  provided with a control grip hole  103  and having a wall surface disposed with a recessed hole  104 . A ratchet  11  is received in the accommodating groove  100 , and an adjusting block  12  is set in the receiving groove  101  of the main body  10 , with the ratchet teeth  110  of the ratchet  11  meshed with the teeth  120  at one side of the adjusting block  12 . The ratchet  11  is mounted thereon with a sleeve engaging post  111  while the adjusting block  12  has an intermediate portion of another side provided with a projection  121  having two sides respectively formed with a concave arcuate surface  122 . The recessed hole  104  of the main body  10  is fixed therein with a positioning ball  13  and a spring  14 , the positioning ball  13  resisting against one of the two concave arcuate surfaces  122 . A control grip  15  is positioned at an outer side of the main body  10  and connected with the adjusting block  12  by a shaft rod  16 , and a blocking plate  17  to be covered and secured on the main body  10  by fixing members  18  is bored with a through hole  170  for the sleeve engaging post  111  of the ratchet  11  to be inserted therethrough and a shaft hole  171  for receiving the shaft rod  16  therein. Thus, when the control grip  15  is operated to actuate the adjusting block  12  to rotate and have one end transferred to closely lean on one sidewall of the receiving groove of the main body  10 , the ratchet  11  will be held and braked by the adjusting block  12  to carry out one-way gearing. 
     However, the engagement of the ratchet  11  of the conventional ratchet wrench  1  with the teeth  120  of the adjusting block  12  is point contact or line contact; therefore, the ratchet  11  and the teeth  120  of the adjusting block  12  cannot stably carry out meshing transmission, likely to produce tooth skipping and indefinite gearing. In addition, when the adjusting block  12  is actuated to carry out braking to the ratchet  11 , it is only by mutual resisting and engagement of the wall surfaces of the adjusting block  12  and of the receiving groove  101 , which are smooth surfaces unable to produce great frictional force, thus failing to attain good effect of engagement and braking and also apt to slip off. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to offer a ratchet wrench, not only achieving excellent efficacy of engagement and braking while changing rotating direction of a driving gear, but also stabilizing transmission while the ratchet wrench is working. 
     The ratchet wrench mainly includes a main body, a driving gear, a driven gear and a cover. 
     The main body is provided with an operating end having a recessed surface formed in one side, an accommodating chamber and a confining chamber formed inside the recessed surface to communicate with each other, a through hole bored in another side of the operating end to communicate with the accommodating chamber, and an orientating member installed at an outside. 
     The driving gear is installed in the accommodating chamber, provided with plural gear teeth, a positioning projection located at one end for being inserted in the through hole of the main body, and a sleeve-engaging rod located at another end. 
     The driven gear is set in the confining chamber, provided with plural gear teeth to engage with the gear teeth of the driving gear. 
     The cover is laid in the recessed surface of the main body, provided with a through hole for the sleeve-engaging rod of the driving gear to pass through. 
     The ratchet wrench is characterized by having plural ratchet teeth formed on an inner wall of the confining chamber of the main body and the gear teeth of the driven gear also formed with plural ratchet teeth respectively so that the ratchet teeth of the driven gear can restrictively interlock with those ratchet teeth on the confining chamber. The gear teeth of driving gear and the gear teeth of driven gear are formed spirally in order to match and work with each other. The driving gear is bored with a through hole for being inserted with an interactive member having one end connected with the orientating member outside the main body and another end positioned on the cover. The interactive member is further provided with an insert hole for being inserted with a projected bar of a pressing piece. A spring is mounted on the projected bar of the pressing piece between the pressing piece and the interactive member. 
     Furthermore, the operating end of the main body has another side formed with a recessed groove corresponding to the confining chamber. The recessed surface of the main body is bored with plural insert holes to communicate with the recessed groove. The interactive member is provided with a positioning projection located at one end, and a positioning bar located at another end. Laid in the recessed groove of the main body is a blocking plate, which is provided with a through hole for being inserted by the positioning projection of the interactive member, and plural threaded holes to correspond to the insert holes of the recessed groove of the main body. The orientating member is installed at an outside of the blocking plate, bored with an insert hole for a fixing member to pass through to fix on the positioning projection of the interactive member. The cover is further bored with a positioning hole for the positioning bar of the interactive member to insert therein, and plural insert holes corresponding to the insert holes in the recessed surface of the main body. And plural screws can penetrate through the insert holes of the cover and the main body to threadably engage with the threaded holes of the blocking plate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       This invention is better understood by referring to the accompanying drawings, wherein: 
         FIG. 1  is an exploded perspective view of a conventional ratchet wrench; 
         FIG. 2  is an exploded perspective view of a preferred embodiment of a ratchet wrench in the present invention; 
         FIG. 3  is a perspective view of the preferred embodiment of a ratchet wrench in the present invention; 
         FIG. 4  is another perspective view of the preferred embodiment of a ratchet wrench in the present invention; 
         FIG. 5  is a cross-sectional view of the preferred embodiment of a ratchet wrench in the present invention, showing a driving gear being restricted by a driven gear to enable a main body to rotate in a direction for effective gearing; 
         FIG. 6  is a cross-sectional view of the preferred embodiment of a ratchet wrench in the present invention, showing the driving gear being freed to enable the main body to carry out idle rotation in a direction opposite to that in  FIG. 5 ; and 
         FIG. 7  is a cross-sectional view of the preferred embodiment of a ratchet wrench in the present invention, showing the driving gear being restricted by the driven gear to enable the main body to rotate in another direction for effective gearing. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in  FIGS. 2˜5 , a preferred embodiment of a ratchet wrench in the present invention includes a main body  2 , a driving gear  3 , a driven gear  4 , a blocking plate  5  and a cover  6 . 
     The main body  2  is provided with an operating end  20  having a recessed surface  21  formed in one side, with an accommodating chamber  22  and a confining chamber  23  formed to communicate mutually inside the recessed surface  21 . A through hole  220  is bored in one side of the operating end  20  to communicate with the accommodating chamber  22 . A recessed groove  230  is bored in another side of the operating end  20  to correspond to the position of confining chamber  23 . The recessed surface  21  is bored with plural holes  210  are bored to communicate with the recessed groove  230 . The confining chamber  23  has two corresponding portions of the interior wall formed with plural ratchet teeth  231 . 
     The driving gear  3  is installed in the accommodating chamber  22 , provided with plural gear teeth  30  formed spirally, a positioning projection  31  located at one end and a sleeve-engaging rod  32  located at another end. 
     The driven gear  4  is installed in the confining chamber  23 , provided with plural gear teeth  40  to spirally engage with the gear teeth  30  of the driving gear  3 . Each of the gear teeth  40  possesses plural ratchet teeth  41 . In addition, the driven gear  4  is bored with an insert hole  42  inserted with an interactive member  43 , which has an insert hole  430 , a positioning projection  431  located at one end and a positioning bar  432  located at another end. A pressing piece  44  has a projected bar  440  inserted in the insert hole  430 , and a spring  45  is mounted on the projected bar  440  between the interactive member  43  and the pressing piece  44 . 
     The blocking plate  5  is laid in the recessed groove  230  of the main body  2 , provided with a through hole  50 , plural threaded holes  51  corresponding to the insert holes  210  of the main body  2 , an orientating member  52  installed on the outside, and a fixing member  53  inserted through an insert hole  520  of the orientating member  52  to engage with the positioning projection  431  of the interactive member  43 . 
     The cover  6  is laid in the recessed surface  21  of the main body  2 , provided with a through hole  60 , a positioning hole  61  employed to let the positioning bar  432  to pass through, and plural insert holes  62  corresponding to the insert holes  210  of the recessed surface  21  to respectively let plural screws  63  pass through. 
     In assembling, as shown in  FIGS. 2˜5 , the positioning projection  431  of the interactive member  43  is first inserted in the through hole  50  of the blocking plate  5 , with the fixing member  53  to position the orientating member  52  on the positioning projection  431  outside the blocking plate  5 . Then, the blocking plate  5  is placed on the recessed groove  230  of the main body  2 . Next, the spring  45  is mounted around the projected bar  440  of the pressing piece  44 , with the projected bar  440  inserted in the insert hole  430  of the interactive member  43  so that the interactive member  43 , the pressing piece  44  and the spring  45  are enclosed in the confining chamber  23  of the main body  2 . Then, the driven gear  4  is laid in the confining chamber  23  of the main body  2 , with the interactive member  43 , the pressing piece  44  and the spring  45  inserted in the insert hole  42 . Next, the driving gear  3  is placed in the accommodating chamber  22  of the main body  2 , enabling the gear teeth  40  of the driven gear  4  to engage with the gear teeth  30  of the driving gear  3  and the threaded holes  51  of the blocking plate  5  to exactly correspond to the insert holes  210  of the main body  2 . The cover  6  is laid in the recessed surface  21  of the main body  2 , with the engaging rod  32  in the accommodating chamber  22  of the main body  2  to penetrate the through hole  60 , and the positioning bar  432  of the interactive member  43  in the insert hole  42  is inserted in the positioning hole  61 . Then the screws  63  are inserted through the insert holes  62  of the cover  6  and the insert holes  210  of the main body  2  to threadably engage with the threaded holes  51  of the blocking plate  5 . Hence, the driving gear  3  and the driven gear  4  are fixed in the accommodating chamber  22  and the confining chamber  23  of the main body  2  respectively, finishing the assembly of the ratchet wrench. 
       FIGS. 4˜7  show how to operate the ratchet wrench. If the direction of the main body  2  intends to change, it just needs to switch the orientating member  52  to the direction as expected. As shown in  FIGS. 4 and 5 , if the main body  2  intends to operate clockwise, then, all need to do is switching the direction of orientating member  50  clockwise so that it can drive the interactive member  43  to spin. Successively, the interactive member  43  is able to drive the pressing piece  44  to rotate in the insert hole  42  of the driven gear  4 . By the time, as the pressing piece  44  is elastically squeezed by the spring  45 , the driven gear  4  can be moved upward and is as well displaced to contact the upper interior wall of the confining chamber  23  of the main body  2 , as shown in  FIG. 5 , with the ratchet teeth  41  on the teeth  40  of the driven gear  4  interlocked with the ratchet teeth  231  of the confining chamber  23 , making another lower portion of the confining chamber  23  forming a space. As the turning direction of the main body  2  is turned clockwise, the gear teeth  30  of the driving gear  3  will drive the gear teeth  40  of the driven gear  4  counterclockwise, so the driven gear  4  to rotate clockwise as the rotating direction of main body  2  as shown in  FIG. 5 . However, the ratchet teeth  41  of the driven gear  4  are restrictively engaged with the ratchet teeth  231  of the confining chamber  23 , making the driving gear  3  unable to turn around so that a sleeve tool (not shown in FIGS.) engaged with the sleeve-engaging rod  32  of the driving gear  3  can work to screw or unscrew a nut or a bolt. However, if the orientating member  52  is switching counterclockwise to lower position, then, the main body  2  is turned counterclockwise, the driving gear  3  can drive the driven gear  4  to slightly shift downward in the confining chamber  23  as shown in  FIG. 6 . Hence, the ratchet teeth  41  of the gear teeth  40  of the driven gear  4  won&#39;t be tightly engaged with the ratchet teeth  231  of the confining chamber  23 , so that the driven gear  4  can&#39;t be driven by the driving gear  3 . 
     When the ratchet wrench is to be operated counterclockwise, only the orienting member  52  is switched upward counterclockwise in order to change over, moving the orienting member  52  upward counterclockwise to the needed direction for rotating the body  2 , as shown in  FIGS. 4 and 7 . Then the orienting member  52  can drive the interactive member  43  to turn counterclockwise, with the interactive member  43  pushing the pressing piece  44  to turn in the insert hole  42  of the driven gear  4 . Then the driven gear  4  moves downward in the confining chamber  23  of the main body  2 , hence, a space is formed in an upper portion of the confining chamber  23 , with the spring  45  elastically pushing the driven gear  4  move downward and contact with a lower interior wall of the confining chamber  23  as shown in  FIG. 7 . When the ratchet wrench is turned counterclockwise, the teeth  30  of the driving gear  3  turns clockwise to mesh with the teeth  40  of the driven gear  4  and force the driven gear  4  to turn counterclockwise, with the ratchet teeth  41  closed engage with the ratchet teeth  231  of the lower portion of the driven gear  4 , producing a braking state to stop the driving gear  3  completely. So, a sleeve tool, not shown in Figs, fixed on the sleeve-engaging rod  32  of the driving gear  3  can loose or screw tightly a nut or a bolt. If the orienting member  52  is turned counterclockwise upward and the main body  2  is turned clockwise, the driving gear  3  can drive the driven gear  4  slightly toward the upper portion of the confining chamber  23 , forcing the ratchet teeth  41  of the gear teeth  40  of driven gear  4  mesh with the ratchet teeth  231  of the confining chamber  23 , with the driven gear  4  driven by the driving gear  3  to turn, producing idle rotation. 
     Therefore, with the ratchet teeth  41  on the gear teeth  40  of the driven gear  4  to restrictively interlock with the ratchet teeth  231  of the confining chamber  23 , and with the driving gear  3  to cooperate with the driven gear  4 , the ratchet wrench of the invention can work as a stepless driving tool, with a firmly restrictive effect to prevent any slipping off. Moreover, as the gear teeth  30  of the driving gear  3  and the gear teeth  40  of the driven gear  4  are formed spirally, enlarging mutual contact area to make their engagement and transmission firmly, so that the condition like “slipping off” or “transmitting improperly” won&#39;t be happened. 
     While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.