Patent Publication Number: US-6981435-B2

Title: Ratchet wrench having a sealing structure

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 a sealing structure. 
   2. Description of the Related Art 
   A conventional ratchet wrench has an oil seal to prevent the dust or particles from entering the inner space of the ratchet wrench so as to provide a dustproof effect. However, the oil seal cannot be positioned rigidly and stably, thereby decreasing the sealing effect. In addition, the oil seal is easily worn out during a long-term utilization. 
   SUMMARY OF THE INVENTION 
   The primary objective of the present invention is to provide a ratchet wrench having a sealing structure that can be positioned rigidly and stably. 
   Another objective of the present invention is to provide a ratchet wrench, wherein the C-shaped snap can abut and press the oil seal to position the oil seal accurately, so that the oil seal has a better positioning effect. 
   A further objective of the present invention is to provide a ratchet wrench, wherein the oil seal can receive and entirely cover the C-shaped snap to prevent the C-shaped snap from being worn out. 
   In accordance with the present invention, there is provided a ratchet wrench, comprising: 
   a wrench body having a drive head formed with a receiving recess; 
   a ratchet wheel rotatably mounted in the receiving recess of the drive head; 
   a positioning member secured in the receiving recess of the drive head and secured on the ratchet wheel to retain the ratchet wheel in the receiving recess of the drive head; and 
   an oil seal secured in the receiving recess of the drive head and enclosed around the positioning member. 
   In accordance with the present invention, there is also provided a ratchet wrench, comprising: 
   a wrench body having a drive head formed with a receiving recess; 
   a direction control switch rotatably mounted in the receiving recess of the drive head; 
   a positioning member secured in the receiving recess of the drive head and secured on the direction control switch to retain the direction control switch in the receiving recess of the drive head; and 
   an oil seal secured in the receiving recess of the drive head and enclosed around the direction control switch. 
   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 a ratchet wrench in accordance with the preferred embodiment of the present invention; 
       FIG. 2  is a partially side plan cross-sectional assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 3  is a side plan cross-sectional assembly view of the ratchet wrench as shown in  FIG. 1 ; 
       FIG. 3A  is a partially enlarged view of the ratchet wrench as shown in  FIG. 3 ; 
       FIG. 4  is a side plan cross-sectional assembly view of the ratchet wrench in accordance with another embodiment of the present invention; 
       FIG. 5  is a partially enlarged view of the ratchet wrench as shown in  FIG. 4 ; 
       FIG. 6  is a partially exploded perspective view of the ratchet wrench as shown in  FIG. 4 ; 
       FIG. 7  is a perspective assembly view of the ratchet wrench in accordance with another embodiment of the present invention; and 
       FIG. 8  is a side plan cross-sectional view of the ratchet wrench as shown in  FIG. 7 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings and initially to  FIGS. 1–3  and  3 A, a ratchet wrench in accordance with the preferred embodiment of the present invention comprises a wrench body  20 , a ratchet wheel  30 , a pawl member  50 , and a direction control switch  60 . 
   The wrench body  20  has an end formed with a drive head  21 . The drive head  21  has a first portion formed with a first receiving recess  210 , a mediate portion formed with a second receiving recess  22  communicating with the first receiving recess  210 , and a second portion formed with a third receiving recess  23  communicating with the second receiving recess  22 . The first receiving recess  210  has an upper end formed with a protruding shoulder  211  and a lower end formed with a locking groove  212 . The protruding shoulder  211  has a bottom formed with a concave annular groove  214 . 
   The ratchet wheel  30  is rotatably mounted in the first receiving recess  210  of the drive head  21 . The ratchet wheel  30  has an inner wall formed with a polygonal driving portion  32  for driving a workpiece (not shown), such as a nut or the like. The ratchet wheel  30  has an outer wall  31  formed with a plurality of ratchet teeth  311 . 
   The outer wall  31  of the ratchet wheel  30  has a first end formed with an annular locking recess  33  aligning with the annular groove  214  of the protruding shoulder  211  of the drive head  21 . The locking recess  33  has a diameter smaller than that of the outer wall  31  of the ratchet wheel  30 . The ratchet wrench further comprises an oil seal  11  secured in the locking recess  33  of the ratchet wheel  30  and received in the annular groove  214  of the protruding shoulder  211  of the drive head  21  to seal the inner space of the ratchet wheel  30 . The oil seal  11  is rested on the bottom of the protruding shoulder  211  of the drive head  21 . 
   The outer wall  31  of the ratchet wheel  30  has a second end formed with a concave portion  34 . The ratchet wrench further comprises a positioning member  40  (such as a C-shaped snap) secured in the locking groove  212  of the drive head  21  and the concave portion  34  of the ratchet wheel  30  to retain the ratchet wheel  30  in the first receiving recess  210  of the drive head  21 . 
   The ratchet wrench further comprises an oil seal  10  secured in the locking groove  212  of the drive head  21  and the concave portion  34  of the ratchet wheel  30  and is enclosed around the positioning member  40 . Preferably, the oil seal  10  has a substantially inverted L-shaped cross-section. Preferably, the oil seal  10  is formed with a receiving space  101  to receive and locally cover the positioning member  40 . 
   The pawl member  50  is pivotally mounted in the second receiving recess  22  of the drive head  21  and has a first side formed with a plurality of engaging teeth  52  meshing with the ratchet teeth  311  of the ratchet wheel  30 . 
   The direction control switch  60  is rotatably mounted in the third receiving recess  23  of the drive head  21  and is rested on a second side of the pawl member  50  to control a driving direction of the pawl member  50 . 
   In assembly, the positioning member  40  is a C-shaped snap, so that the positioning member  40  has an outward expanded elastic force during the mounting process so as to abut and press the oil seal  10 , so that the oil seal  10  has a better positioning effect. In addition, the pressing force applied by the positioning member  40  on the oil seal  10  is limited by the wall of the locking groove  212  of the drive head  21  and the wall of the concave portion  34  of the ratchet wheel  30 , so that the positioning member  40  produces an upward pressing force to press the oil seal  11 , so that the oil seal  11  has a better positioning effect. 
   Referring to  FIGS. 4–6 , the ratchet wrench in accordance with another embodiment of the present invention is shown, wherein the oil seal  10 A has a substantially inverted U-shaped cross-section and is formed with a receiving space  101 A to receive and entirely cover the positioning member  40 . 
   Referring to  FIGS. 7 and 8 , the ratchet wrench in accordance with another embodiment of the present invention is shown, wherein the direction control switch  60  is retained by the positioning member  40 ′ and the oil seal  10 ′. 
   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.