Patent Publication Number: US-RE41296-E

Title: Retainer ring for securely retaining a first object to a second object

Description:
CROSS- REFERENCE TO RELATED APPLICATIONS    
     
       This application is a reissue application of U.S. Pat. No.  6 , 691 , 593 , issued Feb.  17 ,  2004 , and filed on Mar.  8 ,  2002 , with application Ser. No.  10 / 094 , 342 , and claims priority from Taiwanese Patent Application No.  90220753  U, filed Nov.  28 ,  2001 . 
     
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a retainer ring for securely retaining a first object, e.g., an adaptor or a bit, to a second object, e.g., a box end of a wrench or a shank of a screwdriver. 
     2. Description of the Related Art 
       FIG. 12A  of the drawings illustrates a conventional retainer ring  1  engaged in an annular groove  3  of an object  2 , e.g., an adaptor. After mounting on the object  2 , the retainer ring  1  could move to a position shown in  FIG. 12B  under the action of gravity. This is because there is no means for securely retaining retainer ring  1  in the annular groove  3 . As a result, as illustrated in  FIG. 13 , it would be impossible to mount the object  2  into a receiving compartment  4  of, e.g., a box end of a wrench, as the retainer ring  1  protrudes too much outward to be inserted into the receiving compartment  4 . 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a retainer ring for securely retaining a first object to a second object. 
     In an embodiment of the invention, the first object is an adaptor and the second object is a box end of a wrench. In another embodiment of the invention, the first object is a bit and the second object is a shank of a screwdriver. 
     A retainer ring in accordance with the present invention comprises at least two holding sections and at least one engaging section. Each holding section has a radius of curvature equal to a diameter  radius of a reduced section of a first object. The engaging section has a radius of curvature greater than that of the holding sections. The holding sections securely clamp the reduced section of the first object with the engaging section partially protruding out of the reduced section of the first object for engaging with a second object. 
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a wrench, an adaptor, and a retainer ring in accordance with the present invention. 
         FIG. 1A  is a plan view of the retainer ring in accordance with the present invention. 
         FIG. 2  is a bottom view of the adaptor and the retainer ring in an assembled state. 
         FIG. 3  is a sectional view of an end of the wrench, the adaptor, and the retainer ring in FIG.  2 . 
         FIG. 4  is a sectional view similar to  FIG. 3 , illustrating use of the retainer ring with an end of a wrench having a hexagonal inner periphery. 
         FIG. 5  is a sectional view similar to  FIG. 3 , illustrating a modified embodiment of the retainer ring in accordance with the present invention. 
         FIG. 6  is an exploded perspective view illustrating a wrench, an adaptor, and another embodiment of the retainer ring in accordance with the present invention. 
         FIG. 7  is a bottom view of the adaptor and the retainer ring of  FIG. 6  in an assembled state. 
         FIG. 8  is a sectional view of the end of the wrench, the adaptor, and the retainer ring in FIG.  7 . 
         FIG. 9  is an exploded perspective view illustrating a bit, a screwdriver, and another modified embodiment of the retainer ring in accordance with the present invention. 
         FIG. 10  is a sectional view illustrating engagement between the bit, the screwdriver, and the retainer ring in FIG.  9 . 
         FIG. 11  is a view illustrating use of the retainer ring in a shank having a circular receiving compartment. 
         FIG. 12A  is a sectional view illustrating engagement between a conventional retainer ring and an adaptor. 
         FIG. 12B  is a sectional view illustrating anomalous engagement between the retainer ring and the adaptor in FIG.  12 A. 
         FIG. 13  is a schematic sectional view illustrating difficulty of attaching the adaptor with the retainer ring mounted thereon to a wrench. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , in accordance with the present invention, a retainer ring  10  is provided to securely retain a first object, e.g., an adaptor  20  to a second object, e.g., a box end of a wrench  30 . The adaptor  20  includes a first end  21  engaged in a receiving compartment  31  of the box end of a wrench  30  and a second end  24  that acts as a drive end for engaging with and driving a socket (not shown). A spring-biased ball  25  is mounted to the drive end  24  of the adaptor  20  for releasably engaging with the socket, which is conventional and therefore not described in detail. The first end  21  of the adaptor  20  includes a hexagonal engaging portion  22  with a reduced section in which an annular groove  23  is defined. 
     Referring to  FIG. 1A , the retainer ring  10  is resilient and includes at least two radially inward holding sections  11  and at least one radially outward engaging section  12 . Namely, the engaging section  12  is located in a position radially outward of the holding sections  11 . In this embodiment, the retainer ring  10  includes three holding sections  11  located on two distal ends  11 a of the retainer ring  10  and a section  11 b of the retainer ring  10  opposite to an opening  13  of the retainer ring  10  between the distal ends  11 a. As illustrated in  FIG. 1A , each holding section  11  has a radius of curvature r 1  from a center  0  equal to half of a diameter of the annular groove  23  defined in the reduced section of the engaging portion  22 . Further, the retainer ring  10  includes two engaging sections  12  on both sides of the section  11 b opposite to the opening  13  of the retainer ring  10 . Each engaging section  12  has a radius of curvature r 2  greater than the radius of curvature r 1  of the holding sections  11 . Preferably, the retainer ring  10  has a uniform thickness d. Preferably, the radius of curvature r 2  of the engaging sections  12  is greater than the radius of curvature r 1  of the holding sections  11  by an amount t less than a thickness d of the retainer ring  10 . 
     Thus, when the retainer ring  10  is mounted in the annular groove  23  of the adaptor  20 , the holding sections  11  of the retainer ring  10  securely clamp a bottom wall  231  defining the annular groove  23 . Thus, the retainer ring  10  is securely engaged in the annular groove  23  of the adaptor  20  without the risk of relative movement therebetween. This is owing to the fact that each holding section  11  has a radius of curvature r 1  equal to half of a diameter of the reduced section of the engaging portion  22 . Each engaging section  12  of the retainer ring  10  protrudes beyond the annular groove  23  of the adaptor  20  (see the solid black lines R and the dashed lines between the solid black lines R). 
     Referring to  FIG. 3 , when the adaptor  20  coupled with the retainer ring  10  is mounted in a dodecagonal receiving compartment  31  of a wrench  30 , the retainer ring  10 , when compressed, would not move or wobble in the annular groove  23  of the adaptor  20 , as the three holding sections  11  of the retainer ring  10  securely clamp the bottom wall  231  defining the annular groove  23  of the adaptor  20 . Further, the engaging sections  12  engage with the dodecagonal inner periphery of the receiving compartment  31  at six points P. Thus, the adaptor  20  is securely engaged in the receiving compartment  31  of the wrench  30 . 
     When the adaptor  20  coupled with the retainer ring  10  is mounted in a polygonal receiving compartment  31  of a wrench  30 , as illustrated in  FIG. 4 , the retainer ring  10 , when compressed, would not move or wobble in the annular groove  23  of the adaptor  20 , as the three holding sections  11  of the retainer ring  10  securely clamp the bottom wall  231  defining the annular groove  23  of the adaptor  20 . Further, the engaging sections  12  engage with the hexagonal inner periphery of the receiving compartment  31  at four points P. Thus, the adaptor  20  is securely engaged in the receiving compartment  31  of the wrench  30 . 
       FIG. 5  illustrates a modified embodiment of the retainer ring  10 , wherein like numerals denotesdenote like elements. In this embodiment, the engaging portion (now designated by  22 ′) of the adaptor  20  is circular, and wrench  30  has a circular receiving compartment  33 . When mounting  the adaptor  20  coupled with the retainer ring  10  is mounted in the circular receiving compartment  33  of the wrench  30 , as illustrated in  FIG. 5 , the retainer ring  10 , when compressed, would not move or wobble in the annular groove  23  of the adaptor  20 , as the three holding sections  11  of the retainer ring  10  securely clamp the bottom wall  231  defining the annular groove  23  of the adaptor  20 . Further, the whole engaging sections  12  engage with the circular inner periphery of the receiving compartment  33  (see the solid black lines R in FIG.  5 ). Thus, the adaptor  20  is securely engaged in the receiving compartment  33  of the wrench  30 . 
       FIG. 6  illustrates another modified embodiment of the present invention, wherein like numerals denotesdenote like elements. In this embodiment, the retainer ring  10 ′ includes a radially outward engaging section  12 ′ opposite to an opening  13 ′ of the retainer ring  10 ′ and two radially inward holding sections  11 ′. Each radially inward holding section  11 ′ includes an associated one of the distal ends (not labeled) of the retainer ring  10 ′. The radii of the holding section  11 ′ and the engaging section  12 ′ in this embodiment are respectively the same as that of the holding section  11  and the engaging section  12  of the embodiment shown in FIG.  1 A. 
     As illustrated in  FIG. 7 , when mounting the retainer ring  10 ′ to the adaptor  20 , the holding sections  11 ′ of the retainer ring  10 ′ securely clamp the bottom wall  231  defining the annular groove  23  of the adaptor  20  without the risk of relative movement therebetween. Further, the engaging section  12 ′ of the retainer ring  10 ′ protrudes beyond the annular groove  23  of the adaptor  20 . 
     When mounting the adaptor  20  coupled with the retainer ring  10 ′ is mounted in a dodecagonal receiving compartment  31  of a wrench  30 , as illustrated in  FIG. 8 , the retainer ring  10 ′, when compressed, would not move or wobble in the annular groove  23  of the adaptor  20 , as the holding sections  11 ′ of the retainer ring  10  securely clamp the bottom wall  231  defining the annular groove  23  of the adaptor  20 . Further, the engaging section  12 ′ engages with the dodecagonal inner periphery of the receiving compartment  31  at four points P. Thus, the adaptor  20  is securely engaged in the receiving compartment  31  of the wrench  30 . 
       FIG. 9  illustrates a further modified embodiment of the present invention. In this embodiment, the retainer ring  10 ′ includes a radially outward engaging section  12 ′ opposite to an opening  13 ′ of the retainer ring  10 ′ and two radially inward holding sections  11 ′. Each radially inward holding section  11 ′ includes an associated one of the distal ends (not labeled) of the retainer ring  10 ′. The retainer ring  10 ′ securely retains a bit  20 ′ to a shank  30 ′ of a screwdriver. An end  22 ′ of the bit  20 ′ is hexagonal and includes a reduced section having an annular groove  23 ′ defined by a bottom wall  231 ′. A drive end  24 ′ is formed on the other end of the bit  20 ′. The shank  30 ′ of the screwdriver includes a receiving compartment  32 ′. The radii of the holding section  11 ′ and the engaging section  12 ′ in this embodiment are respectively the same as that of the holding section  11  and the engaging section  12  of the embodiment shown in FIG.  1 A. 
     As illustrated in  FIG. 10 , when mounting the retainer ring  10 ′ to the bit  20 ′, the holding sections  11 ′ of the retainer ring  10 ′ securely clamp the bottom wall  231 ′ defining the annular groove  23 ′ of the bit  20 ′ without the risk of relative movement therebetween. Further, the engaging section  12 ′ of the retainer ring  10 ′ protrudes beyond the annular groove  23 ′ of the bit  20 ′. 
     When the bit  20 ′ coupled with the retainer ring  10 ′ is mounted in the hexagonal receiving compartment  32 ′ of the shank  30 ′, as illustrated in  FIG. 10 , the retainer ring  10 ′, when compressed, would not move or wobble in the annular groove  23 ′ of the bit  20 ′, as the holding sections  11 ′ of the retainer ring  10 ′ securely clamp the bottom wall  231 ′ defining the annul groove  23 ′ of the bit  20 ′. Further, the engaging section  12 ′ engages with the hexagonal inner periphery of the receiving compartment  32 ′ at three points P. Thus, the bit  20 ′ is securely engaged in the receiving compartment  32 ′ of the shank  30 ′. 
       FIG. 11  illustrates still another modified embodiment that is modified from the embodiment of  FIGS. 9 and 10 . In this embodiment, the end  22 ′ of the bit  20 ′ is circular and the receiving compartment (now designated by  33 ′) of the shank  30 ′ is also circular. When the bit  20 ′ coupled with the retainer ring  10 ′ is mounted in the circular receiving compartment  33 ′ of the shank  30 ′, as illustrated in  FIG. 10 , the retainer ring  10 ′ would not move or wobble in tothe annular groove  23 ′ of the bit  20 ′ when compressed, as the holding sections  11 ′ of the retainer ring  10 ′ securely clamp the bottom wall  231 ′ defining the annular groove  23 ′ of the bit  20 ′. Further, the engaging section  12 ′ engages with the circular inner periphery of the receiving compartment  33 ′ (see the solid black line R). Thus, the bit  20 ′ is securely engaged in the receiving compartment  33 ′ of the shank  30 ′. The radii of the holding section  11 ′ and the engaging section  12 ′ in this embodiment are respectively the same as that of the holding section  11  and the engaging section  12  of the embodiment shown in FIG.  1 A. 
     It is noted that the numbers  number and the shapes of the holding sections  11 ,  11 ′ and the engaging sections  12 ,  12 ′ may vary according to the need. 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed.