Patent Publication Number: US-6701808-B2

Title: Wrench capable of preventing a screwed member from slipping out and holding the screwed member

Description:
BACKGROUND OF THE INVENTION 
     The present invention is related to a hand tool, and more particularly to a wrench having a box end. When the box end of the wrench is fitted onto a hexagonal screwed member, the box end is able to stop the screwed member from slipping from the wrench. Furthermore, the box end is able to hold the screwed member. 
     A conventional wrench has a box end formed with a polygonal socket for fitting onto and driving a screwed member such as a nut or a bolt. The socket passes through the box end so that when the box end of the wrench is fitted onto the screwed member, the screwed member is likely to slip out of the socket. This results in inconvenience in operation. Many kinds of improved wrenches with stopping effect have been developed to prevent the screwed member from slipping from the wrench. 
     FIG. 1 shows a conventional wrench  10  having a polygonal socket  11 . A projecting section  12  is formed on the top edge of each inner corner. When the wrench is fitted onto a nut  14 , the projecting sections  12  serve to stop the nut as shown in FIG.  2 . 
     FIGS. 3 and 4 show another type of conventional wrench  15  having a head section  16 . A ring body  17  is inlaid in the head section  16  and protrudes from the inner circumference into the socket  18  for stopping a nut. 
     Both the above stopper structures have shortcomings. For example, when the wrench is fitted onto the screwed member, the screwed member is prevented from upward slipping out of the socket. However, when lifting the wrench, the screwed member still will downward slip out of the socket. In other words, the wrench is unable to hold the screwed member in the socket. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the present invention to provide a wrench capable of preventing a screwed member from slipping out of the socket of the wrench. Furthermore, the wrench is able to hold the screwed member. 
     The present invention can be best understood through the following description and accompanying drawings wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a conventional wrench; 
     FIG. 2 shows the use of the conventional wrench of FIG. 1; 
     FIG. 3 is a perspective exploded view of another type of conventional wrench; 
     FIG. 4 is a sectional assembled view according to FIG. 3; 
     FIG. 5 is a perspective view of a preferred embodiment of the present invention applied to a fixed wrench; 
     FIG. 6 is a perspective exploded view according to FIG. 5; 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG. 6; 
     FIG. 8 is a sectional view according to FIG. 5, showing that the wrench is fitted onto a screwed member; 
     FIG. 9 is a sectional view taken along line  9 — 9  of FIG. 8; 
     FIG. 10 is a view according to FIG. 8, showing that the screwed member is held in the socket of the wrench; 
     FIG. 11 is a sectional view taken along line  11 — 11  of FIG. 10; 
     FIG. 12 shows that the retainer ring of FIG. 5 is applied to a ratchet wrench; 
     FIG. 13 is a longitudinal sectional view according to FIG. 12; 
     FIG. 14 is a sectional view of another embodiment of the present invention applied to a fixed wrench; 
     FIG. 15 is a view according to FIG. 14, showing that the present invention is applied to a ratchet wrench; 
     FIG. 16 is a perspective view of another embodiment of the retainer ring of the present invention; 
     FIG. 17 is a top enlarged view of a part of FIG. 16; 
     FIGS. 18 and 19 show that the retainer ring of FIG. 16 is mounted in the wrench in an operated state; and 
     FIG. 20 shows still another embodiment of the retainer ring of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The wrench of the present invention can be a fixed wrench  20  as shown in FIGS. 5 and 6 or a ratchet wrench as shown in FIG.  12 . 
     Referring to FIGS. 5 and 6, the wrench  20  has a box end  22 . The head section  24  of the box end  22  is formed with a polygonal socket  25  which is generally hexagonal or dodecagonal. The socket  25  has multiple teeth  26 . The circumference of the socket  25  is formed with an annular groove  28 . 
     A retainer ring  30  is inlaid in the annular groove  28 . The retainer ring  30  is a resiliently stretchable ring body. In this embodiment, the ring body has a split  31  and can be resiliently stretched. FIG. 7 shows the cross-section of the retainer ring  30 . An inner side of the top of the cross-section is formed with an upper slope  32 , while an inner side of the bottom thereof is formed with a lower slope  34 . The outer side of the cross-section is formed with an arched face  35 . 
     Referring to FIG. 8, in normal state, the retainer ring  30  is positioned in the annular groove  28  in the socket  25 . A gap exists between the outer edge of the retainer ring  30  and the inner circumference  281  of the annular groove  28 , whereby a space is reserved for the retainer ring  30  to stretch. The inner edge of the retainer ring protrudes into the socket. 
     FIGS. 8 and 9 show a using state of the wrench  20 . When the socket  25  of the wrench is fitted onto a screwed member  40 , the six corners  42  of top end of the screwed member  40  abut against the lower slope  34  of the retainer ring  30 . Therefore, the screwed member is stopped by the retainer ring from upward slipping from the socket. 
     In operation, as shown in FIGS. 10 and 11, the wrench  20  can be forcedly pressed down. Under such circumstance, the top end of the screwed member  40  presses the lower slope  34  to stretch the retainer ring  30 . At this time, the outer circumference of the screwed member can slip into the retainer ring and the six corners  42  are held by the retainer ring. In some operation conditions, this enables a user to more conveniently operate the wrench. 
     It should be noted that the top end of the screwed member  40  has a tapered face  44  as shown in FIGS. 10 and 11. Therefore, in the case that the retainer ring is free from the lower slope  34 , the tapered face  44  of the screwed member can still forcedly stretch the retainer ring. 
     FIG. 12 shows another embodiment of the present invention which is a ratchet wrench  50 . As shown in FIG. 13, a ratchet wheel  55  is disposed in a through hole  54  of the head section  52  of the wrench. The ratchet wheel cooperates with a dog member (not shown) to only one-way rotate within the through hole. The ratchet wheel  55  is formed with a polygonal socket  56 . Also, an annular groove  58  is formed in the socket. 
     The retainer ring  30  is inlaid in the annular groove  58  as shown in FIG.  13 . In normal state, a gap exists between the outer edge of the retainer ring  30  and the inner circumference  581  of the annular groove  58 , whereby the retainer ring can be resiliently stretched. The inner edge of the retainer ring protrudes into the socket. When the ratchet wrench  50  is fitted onto a screwed member  40 , the retainer ring also serves to stop the screwed member. The ratchet wrench can be pressed down to stretch the retainer ring. At this time, the screwed member will slip into the retainer ring and held thereby. 
     In the fixed wrench of FIG. 5, the teeth  26  are fully formed in the socket  25  with a height between the top and bottom of the head section  24 . The annular grooves  28 ,  58  of FIGS. 5 and 12 are formed in the sockets  25 ,  56 . 
     FIG. 14 is a sectional view of still another embodiment of the present invention, which is a fixed wrench  60 . The socket  65  of the box end of the wrench has multiple teeth  66 . This embodiment is different from the above embodiments in that the teeth  66  have a certain height H. A wall with thickness S free from any tooth is reserved between the top of the teeth and the top of the head section  64  of the wrench. The wall defines an inner hole  67  communicating with the socket  65 . An annular groove  68  is formed in the inner hole  67 . The retainer ring  30  is inlaid in the annular groove. Also, the inner edge of the retainer ring protrudes into the socket  65  to stop and hold a screwed member  40 . 
     FIG. 15 is a sectional view of a ratchet wrench  70 . A wall with thickness W is reserved between the top of the ratchet wheel  75  mounted in the head section  72  and the top of the head section. The wall defines a tooth-free inner hole  77  communicating with the socket  76  of the ratchet wheel. An annular groove  78  is formed in the inner hole  77 . The retainer ring  30  is inlaid in the annular groove  78 . Also, the inner edge of the retainer ring protrudes into the socket  76  to stop and hold a screwed member  40 . 
     FIG. 16 shows still another embodiment of the retainer ring  80  of the present invention. The retainer ring has two semicircular ring bodies  82 ,  84  which are oppositely adjoined with each other. Two ends of each ring body are respectively formed with two recesses  85 . Two resilient members  86  are respectively disposed in the recesses  85  of the two ring bodies as shown in FIG.  17 . Two ends of each resilient member are respectively hooked on the two ring bodies  82 ,  84 , whereby the retainer ring can be resiliently split. The cross-section of the retainer ring also has an upper slope  87  and a lower slope  88 . 
     The retainer ring  80  is inlaid in the annular groove  92  of a wrench  90  of the above wrenches. In FIG. 18, the retainer ring is resiliently forcedly closed by the resilient members  86  to stop the screwed member  40 . When the wrench is pressed down, the retainer ring is resiliently split to hold the screwed member as shown in FIG.  19 . 
     FIG. 20 shows still another embodiment of the retainer ring  100  of the present invention. The retainer ring  100  also has two ring bodies  102 ,  104 . Two opposite ends of the two ring bodies are connected by means of a mortise section  105  and a tenon section  106  inserted therein. An insertion pin  107  is passed through the mortise section  105  and tenon section  106  to form a pivot end. The other two opposite ends of the ring bodies are connected by a resilient member  108  as in FIG.  16 . Accordingly, the retainer ring can be resiliently stretched to stop and hold a screwed member. 
     According to the above arrangement, when operated, the wrench of the present invention not only is able to stop the screwed member from slipping out, but also is able to hold the screwed member.