Patent Publication Number: US-2006016295-A1

Title: Wrench having greater torque

Description:
The present invention is a continuation in part of U.S. patent Ser. No. 10/684,156 assigned to and invented by the inventor of the present invention. Thus the contents of the U.S. patent Ser. No. 10/684,156 is incorporated into the present invention as a part of the specification of the present invention. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a wrench, and more particularly to a wrench having a greater torque.  
      2. Description of the Related Art  
      A conventional wrench in accordance with the prior art shown in  FIG. 4  comprises a wrench body  10  having an end formed with a round driving portion  11 . A center of the driving portion  11  is formed with a round receiving portion  12 . A round ratchet wheel  13  is mounted in the receiving portion  12  of the driving portion  11  and has a periphery formed with a plurality of oblique concave portions  14 , and each of a plurality of rollers  15  is movably mounted in a respective one of the oblique concave portions  14  of the ratchet wheel  13  and each roller is urged by a wall of the receiving portion  12  of the driving portion  11 . Each of the oblique concave portions  14  of the ratchet wheel  13  has a first end formed with a deeper concave portion  141  and a second end formed with a shallower concave portion  142 .  
      Referring to  FIGS. 4, 5  and  6 , in the prior art, each oblique concave portion  14  has two sides, a long side and a short side. In the prior art, when the roller  15  is at a position where one side of the roller  15  is in contact with a periphery of the driving portion  11  and one side of he roller  15  is in contact with a long side of the oblique concave portions  14 , a line C tangent to the periphery of the driving portion  11  and passing through the contact point of the roller  15  and the driving portion  11  is parallel to a line D passing through the long side of the oblique concave portions  14 .  
      The plurality of oblique concave portions  14  are not continuous, namely, two adjacent oblique concave portions  14  are spaced by a section  18  along a periphery of the ratchet wheel  13 . Furthermore, the section  18  is not in contact with an inner wall of the driving portion  11 .  
      In operation, when the driving portion  11  of the wrench body  10  is rotated in the normal direction, each of the rollers  15  is rolled into the shallower concave portion  142  of a respective one of the oblique concave portions  14  of the ratchet wheel  13  and is urged on the wall of the receiving portion  12  of the driving portion  11 , so that the ratchet wheel  13  is combined with the driving portion  11  of the wrench body  10  to rotate therewith. Thus, the ratchet wheel  13  is rotated by rotation of the driving portion  11  of the wrench body  10  so as to rotate a screw member (not shown) mounted in the ratchet wheel  13 .  
      Alternatively, when the driving portion  11  of the wrench body  10  is rotated along a reverse direction, each of the rollers  15  is rolled into the deeper concave portion  141  of a respective one of the oblique concave portions  14  of the ratchet wheel  13  and is detached from the wall of the receiving portion  12  of the driving portion  11 , so that the ratchet wheel  13  is detached from the driving portion  11  of the wrench body  10 . Thus, the driving portion  11  of the wrench body  10  idles in the reverse direction.  
      The defect of the prior art is that since the long side of the oblique concave portions  14  is parallel to the line C, see  FIG. 4 , the roller  15  is possible to roll to one of the two sides, a left side and a right side in  FIG. 4 , so that the roller  15  is at an unstable position. Furthermore, the section  18  is not in contact with the side of the driving portion  11 . Thus, the ratchet wheel  13  cannot tightly resist against the inner wall of the driving portion  11 . Thus the force from the handle cannot be effectively transferred to the ratchet wheel  13  through the driving portion  11  to drive a screw unit.  
     SUMMARY OF THE INVENTION  
      The primary objective of the present invention is to provide a wrench having a greater torque.  
      Another objective of the present invention is to provide a wrench, wherein the resultant driving force of the wrench passes through the ratchet wheel is greater, so that the wrench produces the maximum torque during operation.  
      A further objective of the present invention is to provide a wrench which produces the maximum torque during operation, thereby preventing the wrench from slipping from the screw member due to a smaller torque.  
      In accordance with the present invention, a wrench capable of transferring power effectively comprise a wrench body having an end formed with a driving portion; the driving portion being formed with a receiving portion; a ratchet wheel being mounted in the receiving portion of the driving portion and having a periphery formed with a plurality of oblique concave portions; a plurality of rollers each movably mounted in a respective one of the oblique concave portions of the ratchet wheel and each urged on a wall of the receiving portion of the driving portion; each of the oblique concave portions of the ratchet wheel having a first end formed with a deeper concave portion and a second end formed with a shallower concave portion. Each oblique concave portion has two sides, a long side and a short side. When the roller is at a position where one side of the roller is in contact with a periphery of the driving portion and one side of he roller is in contact with a long side of the oblique concave portions, a line A tangent to the periphery of the driving portion and passing through the contact point of the roller and the driving portion is inclined to the long side of the oblique concave portions. An angle is defined between the long side and a line passing the long side of the oblique concave portions, then the angle is between 5 degrees to 30 degrees. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a partially plan cross-sectional view of a wrench in accordance with the preferred embodiment of the present invention;  
       FIG. 2  is a plan view of a driving portion of the wrench as shown in  FIG. 1 ;  
       FIG. 3  is a locally plan view of the driving portion of the wrench as shown in  FIG. 2 ;  
       FIG. 4  is a partially plan cross-sectional view of a conventional wrench in accordance with the prior art;  
       FIG. 5  is a plan view of a driving portion of the conventional wrench as shown in  FIG. 5 ; and  
       FIG. 6  is a locally plan view of the driving portion of the conventional wrench as shown in  FIG. 5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to the drawings and initially to  FIG. 1 , a wrench in accordance with the preferred embodiment of the present invention comprises the following elements.  
      A wrench body  20  has one end formed with a driving portion  21 . The driving portion  21  is formed with a receiving portion  22 . A ratchet wheel  23  is mounted in the receiving portion  22  of the driving portion  21  and has a periphery formed with a plurality of oblique concave portions  24 .  
      A plurality of rollers  25  is included and each is movably mounted in a respective one of the oblique concave portions  24  of the ratchet wheel  23  and urged on a wall of the receiving portion  22  of the driving portion  21 . Each of the oblique concave portions  24  of the ratchet wheel  23  has a first end formed with a deeper concave portion  241  and a second end formed with a shallower concave portion  242 .  
      Each oblique concave portion  24  has two sides, a long side and a short side. When the roller  25  is at a position where one side of the roller  25  is in contact with a periphery of the driving portion  21  and one side of the roller  25  is in contact with a long side of the oblique concave portions  24 , a line A is tangent to the periphery of the driving portion  21  and passing through the contact point of the roller  25  and the driving portion  21 . The line A is inclined to the long side of the oblique concave portions  24 . An angle θ is defined between the long side and a line B passing the long side of the oblique concave portions  24 . In the present invention, it is preferable, that the angle θ is between 5 degrees to 30 degrees.  
      Furthermore, a periphery point at a periphery of the ratchet wheel  23  between two adjacent oblique concave portions  24  is in contact to an inner wall of the driving portion  21 .  
      Advantages of the present invention is that when the ratchet wheel  23  is tightly engaged to the driving portion  11 , the roller  25  tightly resists against the wall of the driving portion  21 . When driving a screw unit (not shown), the ratchet wheel  23  rotates counterclockwise, so that the roller  25  is driven to be more tightly clamped by the long sides of the oblique concave portion  24  and the inner wall of the driving portion  21 . Moreover since a periphery point at a periphery of the ratchet wheel  23  between two adjacent oblique concave portions  24  is in contact to an inner wall of the driving portion  21 , the driving portion  21  provides a friction force to the ratchet wheel  23 . Thereby the force from the handle can be effectively transferred to the ratchet wheel  23  through the driving portion  21  so as to drive a screw effectively.  
      In operation, when the driving portion  21  of the wrench body  20  is rotated in the normal direction, each of the rollers  25  is rolled into the shallower concave portion  242  of a respective one of the oblique concave portions  24  of the ratchet wheel  23  and is urged on the wall of the receiving portion  22  of the driving portion  21 , so that the ratchet wheel  23  is combined with the driving portion  21  of the wrench body  20  to rotate therewith. Thus, the ratchet wheel  23  is rotated by rotation of the driving portion  21  of the wrench body  20  so as to rotate a screw member (not shown) mounted in the ratchet wheel  23 .  
      Alternatively, when the driving portion  21  of the wrench body  20  is rotated in the reverse direction, each of the rollers  25  is rolled into the deeper concave portion  241  of a respective one of the oblique concave portions  24  of the ratchet wheel  23  and is detached from the wall of the receiving portion  22  of the driving portion  21 , so that the ratchet wheel  23  is detached from the driving portion  21  of the wrench body  20 . Thus, the driving portion  21  of the wrench body  20  idles in the reverse direction.  
      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.