Abstract:
A ratchet wrench includes a first body made of light material and has a first recess, a closed bottom, a first hole, a first groove, a second recess and a shoulder formed between the first and second recesses. A second body made of strong material and has a first portion and a second portion so as to be respectively received in the first and second recesses. The first portion is rested on the shoulder. A ratchet wheel and a pawl respectively received in the second body, and a switch unit is connected to the second body to operate the pawl to be engaged with the ratchet wheel. The ratchet wrench has simple structure and easily assembled and manufactured. The ratchet wrench is light and durable.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Fields of the Invention 
         [0002]    The present invention relates to a ratchet wrench, and more particularly, to a ratchet wrench with light weight and reliable structure. 
         [0003]    2. Descriptions of Related Art 
         [0004]    One of the conventional ratchet wrenches is disclosed in U.S. Pat. No. 4,991,468 and comprises a body with a first recess and a second recess. A ratchet wheel is located in the first recess and has a toothed portion defined in the outside thereof. A bottom cover is connected to the underside of the body. A pawl is received in the second recess and has engaging teeth which are engaged with the toothed portion of the ratchet wheel. A top cover is connected to the top of the body. However, the body is made by steel which is heavy so that the user has to operate by a significant force and the heavy tool may hurt the user&#39;s wrist. Another one of the conventional ratchet wrenches is disclosed in U.S. Pat. No. 3,742,788 and which has similar drawbacks as the U.S. Pat. No. 4,991,468. 
         [0005]    The present invention intends to provide a ratchet wrench which improves the shortcomings mentioned above. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention relates to a ratchet wrench and comprises a body made of light material and has a first recess which has a closed bottom. The first recess has a first side, a second side and a third side, wherein the first and third sides each are a curved side, and the second side is a straight side. The second side is tangent to the first and third sides. A first hole is defined through the closed bottom and shares a common axis with the first side. The diameter of the first side is larger than that of the first hole. A first groove is defined in the inner periphery of the first hole. A second recess is defined in the body and located above the first recess, and is larger than the first recess. A shoulder is formed between the first and second recesses. The second recess is offset from the first recess. The first, second and third sides are located between the closed bottom and the shoulder. 
         [0007]    A second body is made of strong material and has a first portion and a second portion, wherein the first portion is smaller than the second portion. The first portion is received in the first recess and contacts the closed bottom. The second portion is received in the second recess and contacts the shoulder. The second body has a first room, a second room and a third room. The first room, the second room and the third room communicate with each other. The first room is a round through hole. The first room shares a common axis with the first hole. The first room and the first hole have the same diameter. The second room is defined in the inner periphery of the first room. The center of the second room is located within the first room. The diameter of the second room is smaller than that of the first room. The second room has a closed top. The second room has a fourth side. The second side faces the second room which is located between the first and third rooms. The third room is a round hole, and the diameter of the third room is smaller than that of the second room. The third room shares a common axis with the third side. An end face is formed around the top of the second portion. 
         [0008]    A ratchet wheel is pivotably located in the first hole and the first room. The ratchet wheel has a toothed portion defined in the outer periphery thereof. The ratchet wheel has an engaging recess defined in the center thereof. A disk is connected to the top of the ratchet wheel. The periphery of the disk protrudes outward radially from the top of the ratchet wheel. The disk contacts the end face of the second body. The ratchet wheel has a second groove which is located corresponding to the first groove. 
         [0009]    A pawl is located in the second room of the second body and is movable within the second room. The top of the pawl is restricted by the fourth side of the second body. The bottom of the pawl is restricted by the closed bottom of the first body. The pawl has engaging teeth defined in the front side thereof, and the engaging teeth are engaged with the toothed portion of the ratchet wheel. 
         [0010]    A switch unit is pivotably connected to the third room of the second body and controls movement of the pawl in the second room. The switch unit has a switch member, a cap and a spring. The switch member is pivotably connected to the third room. An underside of the switch member contacts the closed bottom of the first body. A lever is connected to the top of the switch member and exposed beyond the second body. The lever contacts the end face. The switch unit has a reception recess which faces the pawl. The cap and the spring are located in the reception recess. The cap is biased by the spring to contact the rear side of the pawl so as to push the pawl to engage the engaging teeth with the toothed portion of the ratchet wheel. The cap contacts the fourth side of the second body to prevent the switch unit from disengaging from the third room. 
         [0011]    A clip is engaged with the first and second grooves to restrict the ratchet wheel within the first hole and the first room. The disk contacts the end face to connect the second body to the first body. 
         [0012]    The primary object of the present invention is to provide a ratchet wrench which is light in weight and durable for use. 
         [0013]    The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is an exploded view of the ratchet wrench of the present invention; 
           [0015]      FIG. 2  is a top view of the first body of the ratchet wrench of the present invention; 
           [0016]      FIG. 3  is a top view of the second body of the ratchet wrench of the present invention; 
           [0017]      FIG. 4  is a perspective view of the ratchet wrench of the present invention; 
           [0018]      FIG. 5  is a top view of the ratchet wrench of the present invention; 
           [0019]      FIG. 6  is a cross sectional view, taken along line B-B in  FIG. 5 ; 
           [0020]      FIG. 7  is a side view of the ratchet wrench of the present invention; 
           [0021]      FIG. 8  is a cross sectional view, taken along line C-C in  FIG. 7 ; 
           [0022]      FIG. 9  is a perspective view of the second embodiment of the ratchet wrench of the present invention; 
           [0023]      FIG. 10  is a perspective view of the third embodiment of the ratchet wrench of the present invention; 
           [0024]      FIG. 11  is a perspective view of the fourth embodiment of the ratchet wrench of the present invention, and 
           [0025]      FIG. 12  is a side view of the fourth embodiment of the ratchet wrench of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Referring to  FIGS. 1 to 3 , the ratchet wrench of the present invention comprises a first body  10  made of light material, such as Aluminum, Magnesium, alloy, plastic or carbon fibers. The first body  10  has a first recess  11  which has a closed bottom  110 . The first recess  11  has a first side  111 , a second side  112  and a third side  113 , wherein the first and third sides  111 ,  113  each are a curved side, and the second side  112  is a straight side. The second side  112  is tangent to the first and third sides  111 ,  113 . A first hole  12  is defined through the closed bottom  110  and shares a common axis with the first side  111 . The diameter of the first side  111  is larger than that of the first hole  12 . A first groove  13  is defined in the inner periphery of the first hole  12 . A second recess  14  is defined in the body  10  and located above the first recess  11 , and is larger than the first recess  11 . A shoulder  15  is formed between the first and second recesses  11 ,  14 . The second recess  14  is offset from the first recess  11 . The first, second and third sides  111 ,  112 ,  113  are located between the closed bottom  110  and the shoulder  15 . 
         [0027]    A second body  20  is made of strong material such as steel, iron or alloy. The second body  20  has a first portion  21  and a second portion  22 , wherein the first portion  21  is smaller than the second portion  22 . The first portion  21  is received in the first recess  11  and contacts the closed bottom  110 . The second portion  22  is received in the second recess  14  and contacts the shoulder  15 . The second body  20  has a first room  23 , a second room  24  and a third room  26 . The first room  23 , the second room  24  and the third room  26  communicate with each other. The first room  23  is a round through hole. The first room  23  shares a common axis with the first hole  12 . The first room  23  and the first hole  12  have the same diameter. The second room  24  is defined in the inner periphery of the first room  23 . The center of the second room  24  is located within the first room  23 . The diameter of the second room  24  is smaller than that of the first room  23 . The second room  24  has a closed top. The second room  24  has a fourth side  25 . The second side  112  faces the second room  24  which is located between the first and third rooms  23 ,  26 . The third room  26  is a round hole, and the diameter of the third room  26  is smaller than that of the second room  24 . The third room  26  shares a common axis with the third side  113 . An end face  27  is formed around the top of the second portion  22 . 
         [0028]    A ratchet wheel  30  is pivotably located in the first hole  12  and the first room  23 . The ratchet wheel  30  has a toothed portion  31  defined in the outer periphery thereof. The ratchet wheel  30  has an engaging recess  32  defined in the center thereof. The engaging recess  32  is a polygonal recess and is a recess with a closed end so as to be directly connected with a socket or other parts. A disk  33  is connected to the top of the ratchet wheel  30 . The periphery of the disk  33  protrudes outward radially from the top of the ratchet wheel  30 . The disk  33  contacts the end face  27  of the second body  20 . The ratchet wheel  30  has a second groove  34  which is located corresponding to the first groove  13 . 
         [0029]    A pawl  40  is located in the second room  24  of the second body  20  and is movable within the second room  24 . The top of the pawl  40  is restricted by the fourth side  25  of the second body  20 . The bottom of the pawl  40  is restricted by the closed bottom  110  of the first body  10 . The pawl  40  has engaging teeth  41  defined in the front side thereof, and the engaging teeth  41  are engaged with the toothed portion  31  of the ratchet wheel  30 . 
         [0030]    A switch unit  50  is pivotably connected to the third room  26  of the second body  20  and controls movement of the pawl  40  in the second room  24 . The switch unit  50  has a switch member  51 , a cap  52  and a spring  53 . The switch member  51  is pivotably connected to the third room  26 . An underside of the switch member  51  contacts the closed bottom  110  of the first body  10 . A lever  511  is connected to the top of the switch member  51  and exposed beyond the second body  20 . The lever  511  contacts the end face  27 . The switch unit  50  has a reception recess  512  which faces the pawl  40 . The cap  52  and the spring  53  are located in the reception recess  512 . The cap  52  is biased by the spring  53  to contact the rear side of the pawl  40  so as to push the pawl  40  to engage the engaging teeth  41  with the toothed portion  31  of the ratchet wheel  30 . The cap  52  contacts the fourth side  25  of the second body  20  to prevent the switch unit  50  from disengaging from the third room  26 . 
         [0031]    A clip  60  is engaged with the first and second grooves  13 ,  34  to restrict the ratchet wheel  30  within the first hole  12  and the first room  23 . The disk  33  contacts the end face  27  to connect the second body  20  to the first body  10 . 
         [0032]    As shown in  FIG. 4 , the first room  23  shares a common axis with the first hole  12 , and the first room  23  and the first hole  12  have the same diameter. The toothed portion  31  of the ratchet wheel  30  is located in the first hole  12  and the first room  23 . The disk  33  and the lever  511  both contact the end face  27  of the second body  20 . 
         [0033]    As shown in  FIGS. 5 and 6 , the first portion  21  of the second body  20  is received in the first recess  11  of the first body  10 , and the first portion  21  is in contact with the closed bottom  110 . The second portion  22  is received in the second recess  14  and contacts the shoulder  15 . The lower end of the switch member  51  contacts the closed bottom  110  of the first body  10 , and the lever  511  contacts the end face  27  of the second body  20 . The clip  60  is engaged with the first and second grooves  13 ,  34  to pivotably connect the ratchet wheel  30  to the first hole  12  of the first body  10  and the first room  23  of the second body  20 . The disk  33  contacts the end face  27  of the second body  20  to connect the second body  20  to the first body  10 . 
         [0034]    As shown in  FIGS. 7 and 8 , the switch unit  50  is pivotably connected to the third room  26  of the second body  20 . The switch unit  50  is operated to control the movement of the pawl  40  in the second room  24 . The pawl  40  is moved left and right to control the ratchet wrench to rotate clockwise and counter clockwise. The cap  52  and the spring  53  are located in the reception recess  512 . The cap  52  is biased by the spring  53  to contact the rear side of the pawl  40  so as to push the pawl  40  to engage the engaging teeth  41  with the toothed portion  31  of the ratchet wheel  30 . The engaging recess  32  is a polygonal recess and is a recess with a closed end so as to be directly connected with a socket or other parts. 
         [0035]    As shown in  FIG. 9 , the engaging recess  32  is a passage defined through the ratchet wheel  30 , and the passage  35  communicates with the second groove  34  and the engaging recess  32 . The clip  60  has a contact end  61  which is located in the passage  35  and protrudes into the engaging recess  32 . 
         [0036]    As shown in  FIG. 10 , the first recess  11  and the second recess  14  of the first body  10  have the same shape and size, and no shoulder is formed. The first and second portions  21 ,  22  have the same shape and size. 
         [0037]    As shown in  FIGS. 11 and 12 , the first body  10  has a connection recess  16  and a threaded recess  17 . The connection recess  16  is defined through the first body  10  and shares a common axis with the third room  26 . The first groove  13  is located at the lower portion of the first hole  12 . The second groove  34  is located at the lower portion of the toothed portion  31  of the ratchet wheel  30 . The clip  60  protrudes beyond the first body  10  so as to be easily assembled and dis-assembled. The threaded recess  17  is located at the lower end of the connection recess  16 . The switch member  51  has an insertion  513  which is pivotably connected to the connection recess  16 . The distal end of the insertion  513  is threadedly connected to the threaded recess  17 . A nut  70  is connected to the distal end of the insertion  513 . The switch unit  50  is pivotably connected to the third room  26  of the second body  20 . 
         [0038]    Yet another embodiment of the present invention is that the engaging recess  32  is a rectangular head so as to be connected with a socket, a connector or a universal joint. 
         [0039]    The first body  10  is made of light material, such as Aluminum, Magnesium, alloy, plastic or carbon fibers, so that the first body is light in weight. The second body  20  is made of strong material such as steel, iron or alloy so that the second body  20  can bear large torque. 
         [0040]    The clip  60  is engaged with the first and second grooves  13 ,  34  to restrict the ratchet wheel  30  within the first hole  12  and the first room  23 . The disk  33  contacts the end face  27  to connect the second body  20  to the first body  10 . 
         [0041]    The cap  52  contacts the fourth side  25  of the second body  20  to prevent the switch unit  50  from disengaging from the third room  26 , and 
         [0042]    When manufacturing the first and second bodies  10 ,  20 , because the first, second and third sides  111 ,  112 ,  113 , and the first hole  12 , the first room  23 , the second room  24  and the third room  26  each have an open side, so that they are manufactured by using drills without other complicated tools. This can reduce the manufacturing cost. 
         [0043]    As shown in  FIG. 11 , the insertion  513  is threadedly connected to the nut  70 , so that the switch unit  50  is securely connected to the wrench. The clip  60  can be easily removed and re-assembled, so that some parts can be easily replaced to expand the range of use of the ratchet wrench of the present invention. 
         [0044]    While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.