Abstract:
A connecting rod assembly is capable of pushing the work head outward to allow more of the part of the work head to be exposed out of the connecting rod assembly, making it easier for the user to pull out the work head, thus solving the problem that it is difficult to pull the work head out of the conventional connecting rod structure since the conventional connecting rod structure doesn&#39;t have any function or devices to move the work head outwards.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a connecting rod assembly, and more particularly to a connecting rod assembly for quick connecting and releasing a work head. 
         [0003]    2. Description of the Prior Art 
         [0004]    The operation of screwing and unscrewing screws normally requires the use of a connecting rod which is provided with a replaceable work head at one end thereof, and the other end of the connecting rod is to be clamped and driven to rotate by a pneumatic tool, so that the work head at the end of the connecting rod is rotated to screw or unscrew screws. In order to quickly replace the work head, the connecting rod is usually provided with a quick release unit, pushing or releasing a sleeve of the quick release unit can allow for quick insertion (assembling) or pulling (releasing) of the work head. 
         [0005]    To pull out the work head, the user has to grip the part of the work head that exposed out of the connecting rod and then pulls it out. However, the conventional connecting rod doesn&#39;t have any function or devices to move the work head outwards, so that it is not easy for the user to grip the work head tight (the exposed part of the work head is too small to grip) sometimes when the work head is inserted too deeply, making it difficult to pull out the work head. 
         [0006]    The present invention has arisen to mitigate and/or obviate the afore-described disadvantages. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary object of the present invention is to provide a connecting rod assembly, wherein the work head can be pushed outward to, allow more of the part of the work head to be exposed out of the connecting rod assembly, making it easier for the user to pull out the work head. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an exploded view of a connecting rod assembly and a work head in accordance with the present invention; 
           [0009]      FIG. 2  is a cross sectional view of the connecting rod assembly with a work head in accordance with the present invention; 
           [0010]      FIG. 3  is an operational view in accordance with the present invention showing that the sleeve is pushed toward the work head; and 
           [0011]      FIG. 4  is another operational view in accordance with the present invention showing that the inner spring pushes the link and the work head toward the tube. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]    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. 
         [0013]    Referring to  FIGS. 1 and 2 , a connecting rod assembly in accordance with the present invention is provided for insertion and positioning of a work head  91  and is to be driven by a pneumatic tool  92 . The connecting rod assembly comprises a tube  10 , a rod  20 , an inner spring  31 , a link  40 , a magnet  50 , two first balls  61 , two second balls  62 , a positioning member  63 , an outer spring  32 , a sleeve  70  and an annular member  80 . 
         [0014]    The tube  10  is provided with an axial inner space  11  for insertion of the work head  91 , two first holes  12 , two second holes  13  and a positioning hole  14  formed in an outer surface of the tube  10  and in communication with the axial inner space  11  in such a manner that the positioning hole  14  is disposed between the two first holes  12  and the two second holes  13 , and the first holes  12  are aligned with each other, and so are the second holes  13 . An annular protruding portion  15  is formed on the outer surface of the tube  10  and located between the first holes  12  and the positioning hole  14 , a first annular surface  151  is formed at one end of the annular protruding portion  15  and located adjacent to the two first holes  12 , and a second annular surface  152  is formed adjacent to the second holes  13  and located at another end of the annular protruding portion  15 . It is to be noted that the front section of the axial inner space  11  is hexagonal shaped in cross section to receive the work head  91 , while the rear section of the axial inner space  11  is circular in cross section for insertion of the link  40  and the rod  20 . 
         [0015]    The rod  20  includes an engaging portion  21  to be engaged in the axial inner space  11  of the tube  10 , a connecting portion  22  to be clamped by the pneumatic tool  92 , and an extension portion  23  on which the inner spring  31  is to be mounted. The extension portion  23  and the connecting portion  22  are located at both ends of the rod  20  and the engaging portion  21  is in the middle. 
         [0016]    The inner spring  31  is disposed in the axial inner space  11  and has a first end  311  pressed against the engaging portion  21  of the rod  20  and a second end  312 . 
         [0017]    The link  40  is slidably received in the axial inner space  11  of the tube  10  and includes a first portion  41  to be pressed against the second end of the inner spring  31 , an annular positioning groove  42  formed in the first portion  41 , an annular restricting groove  43  defined by a first wall  431  and an opposite second wall  432 , and a second portion  44 . The link  40  is pushed outward with respect to the tube  10  by the inner spring  31 . 
         [0018]    The magnet  50  is fixed in the second portion  44  of the link  40  and then disposed in the axial inner space  11  of the tube  10  together with the link  40  to position the work head  91  through magnetic attraction. The first balls  61  are movably disposed in the first holes  12  of the tube  10  to lock or release the work head  91 . 
         [0019]    The second balls  62  are movably disposed in the second holes  13  of the tube  10  to lock or release the annular positioning groove  42  of the link  40 . 
         [0020]    The positioning member  63  is a ball which is provided with a positioning portion  631  to be engaged in the positioning hole  14  of the tube  10  and a restricting portion  632  to be disposed between the first and second walls  431 ,  432  to prevent the link  40  from being pushed to disengage from the tube  10  by the inner spring  31 . 
         [0021]    The outer spring  32  is mounted on the tube  10  and includes a first end  321  to be pressed against the second annular surface  152  and a second end  322 . 
         [0022]    The sleeve  70  is slidably sleeved onto the tube  10  and formed with an axial inner space  71  and a pressing portion  72  at one end of the axial inner space  71 . The pressing portion  72  is formed with an annular pressing surface  721  to press against or disengage from the first balls  61 , and a pressing end surface  722  to press against or to move away from the first annular surface  151 . When the pressing end surface  722  is disengaged from the first annular surface  151  and the annular pressing surface  721  is not pressed against the first balls  61 , an avoiding space  73  will be formed between the sleeve  70  and the tube  10  to receive the first balls  61 , as shown in  FIG. 3 . 
         [0023]    The annular member  80  is slidably sleeved on the tube and includes an annular inserting portion  81  to be inserted at another end, of the axial inner space  71  of the sleeve  70 , an annular end surface  811  formed on the annular inserting portion  81  and to be pressed against the second end  322  of the outer spring  32 , an annular pressing surface  812  serving to press against or disengage from the second balls  62 , and a receiving groove  82  for reception of the second balls  62 . 
         [0024]    The abovementioned are the structural relations of the main components of the present invention, and the operation and effect of the embodiment of the present invention are described as follows. 
         [0025]    As shown in  FIG. 2 , the work head  91  is inserted in the axial inner space  11  of the tube  10  and positioned therein by the engagement of the first balls  61  and the magnetic attraction of the magnet  50 . Meanwhile, the link  40  is pushed inwards by the work head  91  to compress the inner spring  31  in such a manner that the annular positioning groove  42  of the link  40  is engaged with the second balls  62  to hold (position) the link  40 , and thus the rod  20  is kept in a work position. 
         [0026]    Referring then to  FIGS. 3 and 4 , to pull out the work head  91 , the sleeve  70  is pushed a certain distance toward the work head  91 , so that the annular member  80  is pushed by the sleeve  70  to compress the outer spring  32 . Meanwhile, the second balls  62  disengage from the annular pressing surface  812  and engage with the receiving groove  82 . Furthermore, the first balls  61  disengage from the annular pressing surface  721  of the sleeve  70  and engage in the avoid space  73  after the sleeve  70  is pushed toward the work head  91 . At this moment, since the first and second balls  61 ,  62  are released from being pressed by the annular pressing surfaces  721 ,  812  respectively; the inner spring  31  is decompressed to push the link  40  and the work head  91  to move out of the tube  10  until the second wall  432  of the link  40  is stopped against the restricting portion  632  of the positioning member  63 , as shown in  FIG. 4 . At this moment, the second balls  62  will be pushed by the first portion  41  of the link  40  to move into the receiving groove  82  of the annular member  80 . Before the link  40  is pushed inward and the second balls  60  are still engaged in the annular positioning groove  42 , the sleeve  70  is maintained in its after-being-pushed position. The distance that the work head  91  is pushed outward equals the distance between the first and second walls  431 ,  432  of the link  40 . By such arrangements, the work head  91  can be pushed outward to allow more of the area of the work head to be exposed out of the connecting rod assembly, making it easier for the user to pull out the work head  91 . After the work head  91  is pulled out and replaced with a new work head, the new work head pushes the link  40  inwards to decompress the outer spring  32 , thus returning the rod  20  back to its work position. 
         [0027]    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.