Abstract:
An open end ratchet wrench is defined with a gap which allows the ratchet wrench to pass through a pipe or obstacle to carry out rotation, thus improving the operability and convenience of the wrench. Both ends of the open end ratchet wrench extend outward to form a stopping piece, respectively. The stopping pieces allow the toothed pawl to be well positioned and prevent it from disengaging, thus maintaining a stable torque and making the ratchet wrench easy to use.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a hand tool, and more particularly to an open end ratchet wrench. 
         [0003]    2. Description of the Prior Art 
         [0004]    Hand tools are indispensible to many works, take the wrench as an example, an open end wrench is easy to use since it can be used to rotate a fastener directly by passing though barrier. In many situations, however, the user has to repeatedly attach the wrench to the fastener to be rotated, take it off and then attach it again to the fastener, in order continue the rotation of the fastener. Hence, a ratchet wrench appeared, which is rotatable in a unidirectional manner, so that the user can keep turning the wrench without taking it off the fastener, and thus the ratchet wrench is much improved in operability. However, in some situations, during the assembly of a cooler pipeline for example, the fastener maybe located at the end of the pipeline, so it cannot be rotated by a ratchet wrench without disassembling the pipeline and conventionally, it can only be screwed or unscrewed by an open end wrench. Hence, the author of the invention made an open end ratchet wrench. 
       SUMMARY OF THE INVENTION 
       [0005]    The primary object of the present invention is to provide an open end ratchet wrench which can be inserted on pipe directly via its gap, so that its operability and convenience are much improved. 
         [0006]    To achieve the above object, the open end ratchet wrench comprises a head portion, a ratchet and at least one ratchet. The head portion is defined with head portion defined with a receiving hole, a receiving chamber in the receiving hole, and a gap defined in a periphery edge of the head portion. The ratchet is rotatably received in the head portion, an inner surface of the ratchet serves as a work area, the ratchet is provided on its outer periphery with a plurality of teeth and a gap to be aligned with the gap of the head portion. The toothed pawl is received in the receiving chamber of the head portion and provided with a plurality of teeth for meshing with the teeth of the ratchet, one end of the toothed pawl extends outward to form a stopping piece which is shaped corresponding to an outer periphery of the ratchet. By such arrangements, the ratchet wrench provides a better operability and convenience. Furthermore, the stopping piece makes the ratchet rotate smoothly in the receiving hole of the body of the wrench, thus improving the torque performance of the open end ratchet wrench. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of an open end ratchet wrench in accordance with the present invention; 
           [0008]      FIG. 2  is an exploded view of the open end ratchet wrench in accordance with the present invention; 
           [0009]      FIG. 3  is a cross sectional view of the open end ratchet wrench in accordance with the present invention; 
           [0010]      FIG. 4  is an operational view of the open end ratchet wrench in accordance with the present invention; 
           [0011]      FIG. 5  is another cross sectional view of the open end ratchet wrench in accordance with the present invention; 
           [0012]      FIG. 6  shows that the ratchet is being adjusted by rotating the rotary member; 
           [0013]      FIG. 7  is a cross sectional view of a bidirectional open end ratchet wrench in accordance with the present invention; and 
           [0014]      FIG. 8  shows that the bidirectional open end ratchet wrench in accordance with the present invention is provided with two toothed pawl. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. 
         [0016]    Referring to  FIGS. 1-3 , an open end ratchet wrench in accordance with a preferred embodiment of the present invention comprises: a body  10 , ratchet  20 , a rotary member  30 , a C-shaped retainer  40  and a toothed pawl  50 . 
         [0017]    The body  10  comprises a head portion  11  and a handle portion  12 . The head portion  11  is defined with a circular receiving hole  111  and a gap  112  formed in the periphery edge of the head portion  11 , so that the head portion  11  is C-shaped. In the receiving hole  111  is formed an annular groove  113 , and in the inner periphery of the receiving hole  111  close to the handle portion  12  is further defined a crescent-shaped receiving chamber  114  and a restriction recess  115  formed at each of both sides of the receiving chamber  114 . On a side of the receiving chamber  114  opposite the annular groove  113  is further formed a flange  116 . 
         [0018]    The ratchet  20  is rotatably received in the receiving groove  111  of the head portion  11  and abutted against the flange  116  which restricts the ratchet  20  in the receiving groove  111 . The ratchet  20  is C-shaped and provided with a plurality of teeth  21  on its outer surface, and the inner surface of the ratchet  20  is a work area  22  for engaging with a tool or fastener. One end of the ratchet  20  extends outward to form a first joint portion  23 . A gap  24  is formed in the periphery of the ratchet  20  and can be aligned with the gap  112  of the head portion  11 , and the ratchet  20  is further defined with a non-circular engaging portion  25 . 
         [0019]    The rotary member  30  is provided with a second joint portion  31 , a disc-shaped portion  32  connected to the second joint portion  31 , and an annular groove  33  defined between the second joint portion  31  and the disc-shaped portion  32 . The second joint portion  31  is engaged with the first joint portion  23  of the ratchet  20  and restricted by the engaging portion  25 , so that the disc-shaped portion  32  can synchronously drive the ratchet  20  to rotate. The disc-shaped portion  32  protrudes out of the head portion  11  of the body  10  and is provided on its outer periphery with an anti-skid portion  321  which can be in the form of irregular embossing or ribs. The rotary member  30  is further defined with a gap  34  to be aligned with the gaps  112  and  24 . 
         [0020]    The C-shaped retainer  40  is clamped in the annular groove  33  of the rotary member  30 , and after the rotary member  30  is jointed to the ratchet  20 , the C-shaped retainer  40  is expanded outwards and pressed against the inner surface of the annular groove  113  of the head portion  11 . 
         [0021]    The toothed pawl  50  is received in the receiving chamber  114  of the head portion  11  of the body  10  and provided on its surface facing the ratchet  20  with a plurality of teeth  51  for meshing with the teeth  21  of the ratchet  20  and for allowing the ratchet  20  to rotate only in a unidirectional manner. Both ends of the toothed pawl  50  extend to form a stopping piece  52 , respectively. The stopping pieces  52  are arc-shaped corresponding to the outer periphery of the ratchet  20 , and the total length of the toothed pawl  50  including the stopping pieces  52  is longer than the length of each of the gaps  112  and  24 . When the toothed pawl  50  is received in the receiving chamber  114 , the stopping pieces  52  are restricted in the restriction recess  115 , and an elastic member  53  is abutted against the toothed pawl  50  and the bottom of the receiving chamber  114  to make the toothed pawl  50  move elastically in the receiving chamber  114 . 
         [0022]    As shown in  FIG. 4 , when a fastener A is located at the end of a pipeline B, with the gaps  112  and  24 , the head portion of the open end ratchet of the present invention can be inserted on the pipeline B, so that the fastener A can be rotated without disassembling the pipeline B. In the use of the ratchet wrench, when the gap  24  of the ratchet  20  is rotated to the position of the toothed pawl  50 , as shown in  FIG. 5 , the stopping pieces  52  of the toothed pawl  50  will make the ratchet  20  keep abutting against the toothed pawl  50  without being affected by the gap  24  or the receiving chamber  114 , making the ratchet  20  rotate smoothly without seizing up, and meanwhile, preventing the torque value of the wrench from being influenced. 
         [0023]    After the use of the open end ratchet wrench, the gaps  24  and  112  might not be aligned, and at this moment, rotating the rotary member  30  to cause the rotation of the ratchet  20  can make the gaps  24  and  112  aligned. Since the rotary member  30  protrudes out of the head portion  11  and is provided on its outer periphery with the anti-skid portion  321 , the disc-shaped portion  32  is easy to grip. 
         [0024]    The above embodiment is a unidirectional ratchet wrench as an example, but it can also be a bidirectional ratchet wrench, as shown in  FIG. 7 , each of the stopping pieces  52  of the toothed pawl  50  is provided with a plurality of teeth  51  in such a manner that the angular direction of the teeth  51  of one stopping piece  52  is reversed to that of the teeth  51  of the other stopping piece  52 . The bidirectional ratchet wrench is further provided with a diverter member  61  and an elastic member  62 . The diverter member  61  is engaged with the toothed pawl  50  and drives it to swing, and the elastic member  62  serves to push the toothed pawl  50  back to its original position. The diverter member  61  can change the direction of the force applied by the ratchet  20  and improve the operability and convenience of the open end ratchet wrench. In addition, the head portion  11  can further be provided with another receiving chamber  114  in which is disposed another toothed pawl  50 , as shown in  FIG. 8 , so as to provide more engaging points for the ratchet  20 , improving the torque performance of the open end ratchet wrench. 
         [0025]    While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.