Patent Publication Number: US-11376716-B2

Title: Ratchet wrench

Description:
FIELD OF THE INVENTION 
     The present invention relates to a ratchet wrench. 
     BACKGROUND OF THE INVENTION 
     A conventional ratchet wrench comprises a handle and a head formed at one end of the handle. One side of the head is recessed with an accommodating chamber. A rotatable ratchet wheel is provided in the accommodating chamber. The outer side of the accommodating chamber is covered with a cover plate. Two pawls are provided in the accommodating chamber. The pawls are connected with a direction-changing rod. The direction-changing rod is configured to operate the pawls to selectively abut against the ratchet wheel for controlling the rotation direction of the ratchet wheel. 
     For the ratchet wheel to rotate in the accommodating chamber, the head has a first shaft hole, and the cover plate has a second shaft hole corresponding to the first shaft hole. Two sides of the ratchet wheel are provided with a first shaft portion inserting through the first shaft hole and a second shaft portion inserting through the second shaft hole, respectively. Thereby, the ratchet wheel can rotate in the accommodating chamber. 
     However, when the user operates the ratchet wrench, the cover plate is likely to be slightly displaced after being stressed, and the first shaft hole and the second shaft hole are not located on the same axis, resulting in the ratchet wheel does not rotate smoothly. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a ratchet wrench having a bearing ring to locate and lubricate a ratchet wheel so that the ratchet wheel rotates smoothly. 
     In order to achieve the aforesaid object, a ratchet wrench is provided. The ratchet wrench has a head. One side of the head is recessed with a driving chamber. A ratchet wheel is rotatably accommodated in the driving chamber. The driving chamber is covered with a cover plate. Another side of the head, opposite to the driving chamber, is formed with a first shaft hole communicating with the driving chamber. The cover plate has a second shaft hole corresponding to the first shaft hole. The second shaft hole communicates with the driving chamber. The ratchet wheel has an annular toothed portion. A first shaft portion and a second shaft portion are provided on two sides of the annular toothed portion. The first shaft portion is rotatably inserted through the first shaft hole. The second shaft portion is rotatably inserted through the second shaft hole. The ratchet wrench further comprises a bearing ring. The bearing ring is disposed between the ratchet wheel and the cover plate. The bearing ring has a central hole corresponding in size to a diameter of the second shaft portion for the second shaft portion to be inserted therethrough so that the bearing ring can be sleeved onto the second shaft portion of the ratchet wheel. An outer diameter of the bearing ring is greater than an outer diameter of the annular toothed portion. An outer periphery of the bearing ring abuts against an inner wall surface of the driving chamber. 
     In the ratchet wrench provided by the present invention, the bearing ring is sleeved onto the second shaft portion of the ratchet wheel, and the outer periphery of the bearing ring abuts against the inner wall surface of the driving chamber. Therefore, the second shaft portion of the ratchet wheel can be positioned and lubricated by the bearing ring, so that the rotation of the ratchet wheel is smoother. On the other hand, because the bearing ring and the ratchet wheel are separate parts, there is no interference with the processing of the ratchet wheel, and the integrity of the teeth of the ratchet wheel can be maintained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is an exploded view in accordance with the preferred embodiment of the present invention; 
         FIG. 3  is an axial cross-sectional view in accordance with the preferred embodiment of the present invention; 
         FIG. 4  is a radial cross-sectional view in accordance with the preferred embodiment of the present invention; 
         FIG. 5  is an exploded view of the ratchet wheel in accordance with the preferred embodiment of the present invention; and 
         FIG. 6  is a partial enlarged cross-sectional view in accordance with the preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. 
     As shown in  FIG. 1  through  FIG. 6 , the present invention discloses a ratchet wrench  100 . The ratchet wrench  100  comprises a main body  10 , a ratchet wheel  20 , a bearing ring  30 , a direction-changing unit  40 , and a cover plate  50 . 
     The main body  10  has a handle  11  and a head  12  formed at one end of the handle  11 . One side of the head  12  is recessed with a driving chamber  13  and an operating chamber  14  communicating with the driving chamber  13 . The other side of the head  12 , opposite to the driving chamber  13 , is formed with a first shaft hole  15  communicating with the driving chamber  13  and an operating hole  16  communicating with the operating chamber  14 . 
     The ratchet wheel  20  is rotatably accommodated in the driving chamber  13 . The ratchet wheel  20  has an annular toothed portion  21 . A first shaft portion  22  and a second shaft portion  23  are formed symmetrically on two sides of the annular toothed portion  21 . The first shaft portion  22  is rotatably inserted through the first shaft hole  15 . The second shaft portion  23  has a large-diameter section  231  axially extending from the annular toothed portion  21  and a small-diameter section  232  axially extending from the large-diameter section  231 . The diameter of the large-diameter section  231  is greater than the small-diameter section  232 . The second shaft portion  23  is further extended with a connecting portion  24  for connecting a driven member, such as a sleeve. Referring to  FIG. 5 , the ratchet wheel  20  includes sealing structures  25  arranged between the first shaft portion  22  and the annular toothed portion  21 , between the large-diameter section  231  and the annular toothed portion  21  and between the large-diameter section  231  and the small-diameter section  232 , respectively. In this embodiment, the sealing structure  25  is composed of an annular groove  251  and a sealing ring  252  arranged in the annular groove  251 . 
     The bearing ring  30  is disposed in the driving chamber  13 . The bearing ring  30  has a central hole  31  corresponding in size to the diameter of the second shaft portion  23  for the second shaft portion  23  to be inserted therethrough, so that the bearing ring  30  can be sleeved onto the second shaft portion  23  of the ratchet wheel  20 . Referring to  FIG. 6 , the outer diameter of the bearing ring  30  is greater than the outer diameter of the annular toothed portion  21 . The outer periphery of the bearing ring  30  abuts against the inner wall surface  131  of the driving chamber  13 . In this embodiment, the bearing ring  30  is sleeved on the large-diameter section  231  of the second shaft portion  23 . The bearing ring  30  may be a self-lubricating bearing, a ball bearing or a needle roller bearing. 
     The direction-changing unit  40  has a pawl  41  accommodated in the operating chamber  14  and a direction-changing rod  42  inserted through the operating hole  16 . The direction-changing rod  42  is configured to drive the pawl  41  to selectively abut against the annular toothed portion  21  of the ratchet wheel  20 . In this embodiment, one side of the direction-changing rod  42 , facing the pawl  41 , is recessed with an elliptical groove  421 . A spring  43  and an elliptical block  44  are provided in the elliptical groove  421 . The elliptical block  44  is biased by the spring  43  to elastically push the pawl  41  against the annular toothed portion  21 . In this way, the elastic force of the spring  43  can push the pawl  41  evenly through the elliptical design. 
     The cover plate  50  is disposed on the outer sides of the driving chamber  13  and the operation chamber  14  to confine the ratchet wheel  20 , the bearing ring  30  and the direction-changing unit  40  within the driving chamber  13  and the operation chamber  14 . The cover plate  50  has a second shaft hole  51  corresponding to the first shaft hole  15  for the second shaft portion  23  of the ratchet wheel  20  to pass therethrough. In this embodiment, the small-diameter section  232  of the second shaft portion  23  is rotatably inserted through the second shaft hole  51 . 
     Referring to  FIG. 2  and  FIG. 3 , when the ratchet wrench  100  is to be assembled, the center hole  31  of the bearing ring  30  is first fitted on the large-diameter section  231  of the second shaft portion  23  of the ratchet wheel  20 . Then, the ratchet wheel  20  with the bearing ring  30  is placed into the driving chamber  13 , and the first shaft portion  22  of the ratchet wheel  20  is inserted through the first shaft hole  15 . After that, the pawl  41  of the direction-changing unit  40  is placed into the operating chamber  14 , and then the elliptical block  44  and the spring  43  are placed into the elliptical groove  421  of the direction-changing rod  42  to be assembled in the operating hole  16 . Then, the cover plate  50  covers the outer sides of the driving chamber  13  and the operating chamber  14 , and the small-diameter section  232  of the second shaft portion  23  is inserted through the second shaft hole  51  to complete the assembly of the ratchet wrench  100 . Thereby, when in use, the user only needs to operate the direction-changing rod  42  to drive the pawl  41  to selectively abut against the annular toothed portion  21  of the ratchet wheel  20  or not and to control the direction of rotation. This operation is general knowledge, so it won&#39;t be described hereinafter. The present invention emphasizes that, as shown in  FIG. 5 , the second shaft portion  23  of the ratchet wheel  20  is sleeved with the bearing ring  30 , and the outer periphery of the bearing ring  30  abuts against the inner wall surface  131  of the driving chamber  13 . Therefore, the second shaft portion  23  of the ratchet wheel  20  can be positioned and lubricated by the bearing ring  30 , so that the ratchet wheel  20  can rotate smoothly. 
     It is worth mentioning that because the bearing ring  30  and the ratchet wheel  20  are two separate parts, when the teeth of the ratchet wheel  20  are processed, they will not be interfered by the bearing ring  30  and the teeth can be formed completely. This design ensures that the strength of the teeth is not reduced. The number of teeth of the ratchet wheel  20  may be greater than  72 , such as  108  or  144 . 
     Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.