A shock absorber utilizes an internal passage design and cooperates with at least one flow-restricting member and elastic member to change the flow speed and displacement during the extension and retraction of the shock absorber, so as to make the extending and retracting speeds of the shock absorber different for buffering the shake wave to the house, thus reducing the force shaking the house in the earthquake.

BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a shock absorber, and more particularly to a shock absorber which can defeat the inertia to slow the energy compression speed and increase the energy release speed. 
         [0003]    2. Description of the Prior Art 
         [0004]    Taiwan is located at the active plate boundary between the Eurasian plate and the Philippine Sea plate. The huge pressure generated by the collision between the two plates will cause earthquake, and different quake-hit areas in the same earthquake will have different situations. 
         [0005]    So far, Taiwan has certain knowledge about earthquake, but is still unable to forecast precisely where and when the quake occurs is going to happen. Living in such an unstable geological environment, we can't stop an earthquake, but we can do something to reduce the damage caused by it. 
         [0006]    The owner of this application, with many years of technology and experiences in the field of shock absorber, has developed a shock absorber which can solve the above problem. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary objective of the present invention is to provide a shock absorber, which can defeat the inertia displacement of the shock absorber to slow the retracting speed to absorb energy and increase the extending speed to release the energy. 
         [0008]    In order to achieve the above objective, the shock absorber in accordance with the present invention comprises a driving member, a first flow-restricting member, a holder and a second flow-restricting member. 
         [0009]    the driving member includes a driven rod and a piston, one end of the driven rod is assembled with one end of the piston, the piston is formed with a flow-restricting passage. The first flow-restricting member includes a through hole for insertion of the piston, and a flow-restricting portion for cooperating with the flow-restricting passage of the piston. The holder includes an inner tube, a first leak-proof member, a second leak-proof member, a positioning member and an outer tube, the inner tube is used for insertion of the piston of the driving member, both ends of the inner tube are engaged with the first leak-proof member and the second leak-proof member to define a first inner space, the first leak-proof member is provided for insertion of the driven rod of the driving member, the second leak-proof member includes at least one flow-restricting passage, one end of the flow-restricting passage penetrates one end of the second leak-proof member, and the other end of the flow-restricting passage penetrates a side of the second leak-proof member. One end of the positioning member is assembled with one end of the second leak-proof member. The first leak-proof member, the inner tube and the second leak-proof member are disposed in the outer tube and define a second inner space. The flow-restricting passage of the second leak-proof member communicates with the first inner space and the second inner space, respectively. The second flow-restricting member includes a through hole and a flow-restricting portion, the through hole is provided for insertion of the positioning member and assembled with the leak-proof member, and the flow-restricting portion of the second flow-restricting member is provided for cooperating with the second leak-proof member. 
         [0010]    To summarize, the shock absorber in accordance with the present invention has the following advantages: 
         [0011]    The buffer liquid in the shock absorber utilizes the flow-restricting passage, the flow-restricting portion of the first flow-restricting member, the flow-restricting passage of the second leak-proof member and the flow-restricting portion of the second flow-restricting member to cooperate with the first inner space and the second inner space to change the flow speed, respectively to change the flow speed by ways of changing the inner flow passages; and under the condition that the second flow-restricting is restricted by the positioning member, the distance between the second flow-restricting member and the second leak-proof member can be changed with the movement of the piston, when the shock absorber retracts, the speed at which the buffer liquid flows from the first inner space to the second inner space will decrease, when the shock absorber extends, the speed at which the buffer liquid flows from the second inner space to the first inner space will increase, so that the retracting speed of the shock absorber is smaller than the extending speed of the shock absorber. The shock absorber retracts more slowly to absorb energy, and the shock absorber extends more quickly to release energy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an exploded view of a shock absorber in accordance with the present invention; 
           [0013]      FIG. 2  is a first cross-sectional view of the shock absorber in accordance with the present invention; 
           [0014]      FIG. 3  is a second cross-sectional view of the shock absorber in accordance with the present invention; 
           [0015]      FIG. 4  illustrates how the shock absorber in accordance with the present invention is used; 
           [0016]      FIG. 5  illustrates the state of the shock absorber in accordance with the present invention before the earthquake occurs; 
           [0017]      FIG. 6  illustrates the state of the shock absorber in accordance with the present invention after the earthquake occurs; and 
           [0018]      FIG. 7  illustrates that the shock absorber in accordance with the present invention is assembled with springs. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    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. 
         [0020]    Referring to  FIGS. 1-3 , a shock absorber in accordance with the present invention comprises: a driving member  10 , a first flow-restricting member  20 , a holder  30 , a second flow-restricting member  40  and an elastic member  50 . 
         [0021]    The driving member  10  includes a connecting head  11 , a driven rod  12  and a piston  13 . 
         [0022]    The connecting head  11  is formed with a radial restricting hole  111  at one end thereof, and the other end of the connecting head  11  is axially defined with an assembling portion  112  in the form of an inner threaded hole. 
         [0023]    The driven rod  12  is formed at one end thereof with a first assembling portion  121  which is in the form of an outer threaded portion for screwing with the assembling portion  112  of the connecting head  11 , and formed at the other end thereof with a second assembling portion  122  which is in the form of an inner threaded hole to be matched with the piston  13 . 
         [0024]    The piston  13  has one end formed with an assembling portion  131  in the form of an outer threaded portion to be screwed with the second assembling portion  122  of the driven rod  12 . Around the outer surface of the piston  13  are defined three spaced-apart grooves  132  for accommodation of two stopping members  133  and a wear-resistance member  134 , respectively. The stopping members  133  and the wear-resistance member  134  are all O rings. The piston  13  is axially formed with an eccentric flow-restricting passage  135 . 
         [0025]    The first flow-restricting member  20  is a flat piece being axially defined with a central through hole  21  for insertion of the assembling portion  131  of the piston  13 , and at the outer edge of the first flow-restricting member  20  is formed a flow-restricting portion  22 . When the assembling portion  131  of the piston  13  is assembled with the second assembling portion  122  of the driven rod  12 , the flow-restricting member  20  is pressed onto the piston  13  by the driven rod  12  in such a manner that the flow-restricting portion  22  of the first flow-restricting member  20  cooperates with the flow-restricting passage  135 . 
         [0026]    The holder  30  includes an inner tube  31 , a first leak-proof member  32 , a second leak-proof member  33 , a positioning member  34  and an outer tube  35 . 
         [0027]    The inner tube  31  is used for axial insertion of the piston  13  of the driving member  10 , such that the piston  13  is in contact with the inner surface  31  of the holder  30  via the stopping members  133  and the wear-resistance  134 . 
         [0028]    The first leak-proof member  32  is axially defined with a through hole  321  in which are disposed a bush  322 , a stopping member  323  and a guiding member  324 , respectively, which are all O rings. The through hole  321  of the first leak-proof member  32  is provided for axial insertion of the driven rod  12  of the driving member  10  in such a manner that the first leak-proof member  32  is brought into contact with the outer surface of the driven rod  12  by the bush  322 , stopping member  323  and guiding member  324 . Around the outer surface of the first leak-proof member  32  are defined two spaced-apart grooves  325  for accommodation of two stopping members  326 , respectively, which are O rings. One end of the first leak-proof member  32  is engaged with one end of the inner tube  31 , and the outer surface of the first leak-proof member  32  abuts against one end inner surface of the outer tube  35 . 
         [0029]    The second leak-proof member  33  is defined in the outer surface thereof with two spaced-apart grooves  331  for accommodation of two stopping members  332  which are all O rings. One end of the second leak-proof member  33  is defined with an assembling portion  333  which is cylinder-shaped. Around the outer surface of the second leak-proof member  33  is formed a groove  334  for accommodation of a stopping member  335 . The second leak-proof member  33  is further provided with two flow-restricting passages  336  that are not connected to each other. One end of each of the flow-restricting passages  336  penetrates one end of the second leak-proof member  33 , and the other end of each of the flow-restricting passages  336  penetrates a side of the second leak-proof member  33 . The other end of the second leak-proof member  33  is axially defined with a connecting head  337  which is formed with a radial restricting hole  338 . 
         [0030]    The positioning member  34  has one end to be axially assembled with the assembling portion  333  of the second leak-proof member  33 . The assembling portion  333  of the second leak-proof member  33  is engaged with the other end of the inner tube  31 , and the outer surface of the second leak-proof member  33  abuts against the other end inner surface of the outer tube  35 . 
         [0031]    Both ends of the inner tube  31  are engaged with the first leak-proof member  32  and the second leak-proof member  33  to define a first inner pace A. Subsequently, the first leak-proof member  32 , the inner tube  31  and the second leak-proof member  33  are placed into the outer tube  35 . The outer surface of the first leak-proof member  32  is in contact with one end inner surface of the outer tube  32  via the stopping members  326 , and the outer surface of the second leak-proof member  33  is in contact with the other end inner surface of the outer tube  35  via the stopping members  332  in such a manner that a second inner space B is defined between the inner tube  31  and the outer tube  35 . In addition, one end of each of the flow-restricting passages  336  of the second leak-proof member  33  communicates with first inner space A, and the other end of each of the flow-restricting passages  336  of the second leak-proof member  33  communicates with the second inner space B. 
         [0032]    The second flow-restricting member  40  is a flat piece being axially defined with a central through hole  41  for insertion of the positioning member  34 , and at the outer surface of the second flow-restricting member  40  is formed with a flow-restricting portion  42 . When the positioning member  34  is inserted through the through hole  41  of the second flow-restricting member  40  and then assembled with the assembling portion  333  of the second leak-proof member  33 , the second flow-restricting member  41  is pressed onto the second leak-proof member  33  by the positioning member  34  in such a manner that the flow-restricting portion  42  of the second flow-restricting member  40  cooperates the flow-restricting passage  336  of the second leak-proof member  33 . 
         [0033]    The elastic member  50  is a spring mounted on the positioning member  34 . One end of the elastic member  50  elastically abuts against the positioning member  34 , and the other end of the elastic member  50  elastically abuts against the second leak-proof member  33 . 
         [0034]    The first inner space A and the second inner space B of the holder  30  are both pre-filled with an appropriate amount of buffer liquid. The restricting hole  111  of the connecting head  11  of the driving member  10  and the restricting hole  338  of the connecting head  337  of the second leak-proof member  33  respectively cooperate with positioning pieces and screws to position the shock absorber in accordance with the present invention between two beams (as shown in  FIGS. 4 and 5 ), so that when the beams are subjected to external force to shake (please refer to  FIG. 6 ), the driving member  10  and the holder  30  of the shock absorber in accordance with the present invention will extend and retract axially. 
         [0035]    When the shock absorber in accordance with the present invention retracts, the driving member  10  will utilize the driven rod  12  to drive the piston  13  to move axially from the first leak-proof member  32  to the second leak-proof member  33  in the inner tube  31 , so that the buffer liquid between the piston  13  and the second leak-proof member  33  will be compressed to press the second flow-restricting member  40  to abut against assembling portion  333  of the second leak-proof member  33  closely. As a result, the speed at which the buffer liquid in the first inner space A flow to the second inner space B will decrease. 
         [0036]    While the piston  13  moves forwards, under the condition that the first inner space A is fixed, the buffer liquid in the space defined between the piston  13  and the second leak-proof member  33  will move toward the space defined between the first leak-proof member  32  and the piston  13 . The flow of the buffer liquid will be restricted by the flow-restricting passage  135  of the piston  13  and the flow-restricting portion  22  of the first flow-restricting member  20 , and the flow speed of the buffer liquid can be changed by changing the inner flow passage space. 
         [0037]    When the shock absorber in accordance with the present invention extends, the driving member  10  will utilize the driven rod  12  to drive the piston  13  to move axially from the second leak-proof member  33  to the first leak-proof member  32  in the inner tube  31 , and the buffer liquid between the piston  13  and the first leak-proof member  32  will be compressed by the piston, so that the second flow-restricting member  40  will not be pressed to abut against the assembling portion  333  of the second leak-proof member  33  closely. As a result, the speed at which the buffer liquid in the second inner space B flow to the second inner space B through the flow-restricting passage  336  of the second leak-proof member  33  will increase. 
         [0038]    While the piston  13  moves forwards, under the condition that the first inner space A is fixed, the buffer liquid in the space defined between the piston  13  and the first leak-proof member  32  will move toward the space defined between the second leak-proof member  33  and the piston  13 . The flow of the buffer liquid will be restricted by the flow-restricting passage  135  of the piston  13  and the flow-restricting portion  22  of the first flow-restricting member  20 . By such arrangements, the flow-restricting passage  135  of the piston  13  and the flow-restricting portion  22  of the first flow-restricting member  20  can provide such a flow speed that the inertia displacement of the shock absorber can be defeated to decrease the retracting speed of the shock absorber to absorb energy and increase the extending speed of the shock absorber to release the energy. The flow speed of the buffer liquid can be changed by changing the inner flow passage space. 
         [0039]    Referring to  FIG. 7 , the piston  13  is provided with an elastic member  60  at each of two ends thereof in the first inner space A. The elastic members  60  are provided to retain and position the shock absorber for preventing the shock absorber from being shaken to deform uncontrollably. 
         [0040]    The above shock absorber is applicable to houses, motorcycles, cars or mechanical equipments. 
         [0041]    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.