Abstract:
A front fork shock-absorbing damper for use in between an upper front fork tube and a lower front fork tube of a vehicle&#39;s front fork for producing a damping effect upon movement of the upper front fork tube relative to the lower front fork tube includes a control rod movable by an external force between a top locking position where the front fork shock-absorbing damper does no work, and a bottom unlocking position where the front fork shock-absorbing damper is functioning.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to a vehicle, such as a bicycle, motorcycle, etc., and, more specifically, to a damper for use in a front fork of the vehicle.  
         [0003]     2. Description of the Related Art  
         [0004]     A hydraulic shock-absorbing damper of bicycle front fork forces the internal fluid to change the flowing path upon relative movement between the upper front fork tube and the lower front fork tube, thereby absorbing shocks. However, this shock-absorbing damper absorbs active force from the pedals when the rider riding the bicycle upwards on a slope, giving a burden to the rider.  
         [0005]     Therefore, an improved design of front fork shock-absorbing structure is developed to eliminate the aforesaid problem. This improved design of front fork shock-absorbing structure allows the bicycle rider to control the structure to work or not to work subject to different road conditions. According to this design, a control rod is provided and movable between a first position where the bottom end of the control rod blocks the fluid passage to prohibit flowing of the fluid between the upper front fork tube and the lower front fork tube, and a second position where the fluid passage is fully opened for enabling the fluid to circulate between the upper front fork tube and the lower front fork tube. This design of front fork shock-absorbing structure is still not satisfactory in function. Because the control rod is adapted to block the fluid passage directly, it directly receives upward impact pressure from the fluid during relative emotion between the upper front fork tube and the lower front fork tube when the rider riding the bicycle over an uneven road surface. Frequently receiving upward impact pressure from the fluid may cause the parts of the control rod to loose. Further, because the device for controlling the position of the control rod is usually provided at the bottom side of the front fork, it is inconvenient to adjust the position of the control rod.  
       SUMMARY OF THE INVENTION  
       [0006]     It is the primary objective of the present invention to provide a front fork having a shock-absorbing damper for a vehicle, which allows the user to control the front fork shock-absorbing damper to work or not to work accurately.  
         [0007]     It is another objective of the present invention to provide a front fork having a shock-absorbing damper for a vehicle, which has a relief loop design for absorbing sudden impact pressure as the bicycle running over an uneven road surface after the user controlled the front fork shock-absorbing damper not to work.  
         [0008]     To achieve these objectives of the present invention, the front fork comprises an upper front fork tube, a lower front fork tube axially movably coupled to the upper front fork tube, a fluid contained in the upper and lower front fork tubes, and a damper immersed in the fluid and sealedly mounted inside the upper front fork tube. The damper comprises a cylindrical main body, a first blocking member, a first spring member, a second blocking member, a second spring member, a control rod, a third blocking member and a third spring member. The main body has a fluid inlet and a fluid outlet axially extended therethrough, and at least one through hole in communication between the fluid inlet and an outside of the main body. The first blocking member is mounted in the fluid inlet of the main body and movable between a first blocking position where the first blocking member blocks the through hole to prohibit flowing of the fluid from the lower front fork tube upwards to the upper front fork tube, and a first opening position where the first blocking member is moved away from the through hole for enabling the fluid to pass upwards from the lower front fork tube through the fluid inlet and the through hole to the upper front fork tube. The first spring member is mounted in the fluid inlet for holding the first blocking member in the first blocking position. The second blocking member is mounted in the fluid inlet above the first blocking member and movable between a second blocking position where the second blocking member blocks the fluid inlet, and a second opening position where the second blocking member opens the fluid inlet. The second spring member is mounted in the fluid inlet for pushing the second blocking member to the second blocking position. The control rod is inserted into the upper front fork tube and movable by an external force between a locking position where the second blocking member is positioned in the second blocking position, and an unlocking position wherein the control rod pushes the second blocking member to the second opening position and holds the second blocking member in the second opening position. The third blocking member is mounted in the fluid outlet of the main body and movable between a third blocking position where the third blocking member prohibits the fluid from passing upwards from said lower front fork tube through the fluid outlet of the main body to the upper front fork tube, and a third opening position where the fluid is allowed to flow downwards from the upper front fork tube through the fluid outlet to the lower front fork tube. The third spring member is mounted in the fluid outlet for holding the third blocking member in the third blocking position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a sectional view of the present invention where the upper and lower front fork tubes are maintained immovable relative to each other.  
         [0010]      FIG. 2  is an exploded view of the front fork shock-absorbing damper according to the present invention.  
         [0011]      FIG. 3  is a sectional view of the main body of the front fork shock-absorbing damper according to the present invention.  
         [0012]      FIG. 4  is a schematic drawing showing the relationship between the control rod and the second blocking member according to the present invention.  
         [0013]      FIG. 5  is similar to  FIG. 1  but showing the unlocking status of the front fork shock-absorbing damper and downward movement of the upper front fork tube relative to the lower front fork tube.  
         [0014]      FIG. 6  is similar to  FIG. 5  but showing upward movement of the upper front fork tube relative to the lower front fork tube.  
         [0015]      FIG. 7  is similar to  FIG. 1  but showing the front fork shock-absorbing damper set in the locking position and the second blocking member blocked the fluid inlet.  
         [0016]      FIG. 8  is similar to  FIG. 7  but showing the front fork shock-absorbing damper set in the locking status and the fourth blocking member moved to the fourth opening position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     As shown in  FIGS. 1-4 , a front fork  1  is shown comprising an upper front fork tube  1   a , a lower front fork tube  1   b  axially movably coupled to the upper front fork tube  1   a , a fluid A is contained in the upper and lower front fork tubes  1   a  and  1   b , and a front fork shock-absorbing damper  100  sealedly fastened to the inside of the upper front fork tube  1   a  and immersed in the fluid A.  
         [0018]     The damper  100  comprises a main body  10 , a first blocking member  20 , a first spring member  25 , a second blocking member  30 , a second spring member  33 , a spacer member  40 , a first ball  50 , a first ball spring  51 , a second ball  60 , a second ball  25  spring  61 , a control rod  70 , a coupling block  72 , a link  73 , and a guide rod  74 .  
         [0019]     The main body  10  is comprised of a cylindrical casing  11  and a bottom block  12  fastened to the bottom side of the cylindrical casing  11 . The cylindrical casing  11  has a neck  13  on the middle. The main body  10  has a fluid inlet  14  axially extended through the casing  11  and the bottom block  12 , a fluid outlet  15  axially extended through the bottom block  12  and the casing  11  below the neck  13 , two upper shoulders  141  and  151  respectively disposed around the top ends of the fluid inlet  14  and the fluid outlet  15 , two bottom shoulders  142  and  152  respectively disposed around the bottom ends of the fluid inlet  14  and the fluid outlet  15 , two transverse through holes  16  extended across the periphery of the casing  11  below the neck  13  in communication between the fluid inlet  14  and the outside of the main body  10 , and a longitudinal through hole  17  disposed above the neck  13  in axial alignment with the fluid outlet  15 . It is to be noted that only one transverse through hole  16  is shown in the drawings.  
         [0020]     The first blocking member  20  is a hollow cylindrical member mounted in the fluid inlet  14  and vertically (axially) movable between a first blocking position P 1  as shown in  FIG. 1  and a first opening position P 2  as shown in  FIG. 5 , having a block body  21 , an enclosed head  23  axially extended from the bottom side of the block body  21 , and a seal ring  24  fastened to the periphery of the enclosed head  23 . The block body fits the inner diameter of the fluid inlet  14 , having an axial hole  22  axially upwardly extended from the enclosed head  23  to the top side, a first step  221  and a second step  222  formed in the axial hole  22  inside the enclosed head  23  at different elevations.  
         [0021]     The first spring member  25  is mounted in the fluid inlet  14 , having one end stopped at the upper shoulder  141  and the other end inserted into the axial hole  22  and stopped against the first step  221 . The first spring member  25  imparts a downward pressure to the first blocking member  20  to force the enclosed head  23  and the seal ring  24  against the bottom shoulder  142 , thereby holding the first blocking member  20  in the first blocking position P 1  as shown in  FIG. 1 .  
         [0022]     The second blocking member  30  is a hollow cylindrical member mounted in the fluid inlet  14  above the first blocking member  20  and vertically (axially) movable between a second blocking position P 3  as shown in  FIG. 7  and a second opening position P 4  as shown in  FIG. 1 . The outer diameter of the second blocking member  30  is smaller than the inner diameter of the block body  21  of the first blocking member  20 , having an inside hole  31  and a top through hole  32  in communication with the inside hole  31 .  
         [0023]     The second spring member  33  has a relatively smaller diameter than the aforesaid first spring member  25 , and is axially inserted inside the first spring member  25 , having one end, namely, the bottom end stopped at the second step  222  and the other end, namely, the top end extending toward the second blocking member  30  and stopped at the spacer member  40 .  
         [0024]     The spacer member  40  is a rod member press-fitted with the upper part thereof into the inside hole  31  of the second blocking member  30 , having a stop flange  41  extended around the periphery and an axial through hole  42  axially extended through the top and bottom ends thereof in communication between the inside hole  31  of the second blocking member  30  and the fluid inlet  14 . The top side of the stop flange  41  is closely attached to the bottom side of the second blocking member  30 . The bottom side of the stop flange  41  is stopped against the top end of the second spring member  33 .  
         [0025]     The first ball  50 , i.e. the third blocking member, and the first ball spring  51  are mounted in the fluid outlet  15  of the main body  10 . The first ball spring  51  has one end stopped at the bottom shoulder  152  and the other end stopped at the bottom side of the first ball  50 . The first ball spring  51  imparts an upward pressure to the first ball  50  against the upper shoulder  151 , holding the first ball  50  in a third blocking position P 5  as shown in  FIG. 1 . The first ball  50  can be forced away from the upper shoulder  151  by downward flowing force of the fluid A to a third opening position P 6  as shown in  FIG. 6 .  
         [0026]     The second ball  60 , i.e. the fourth blocking member, and the second ball spring  61  are put in the inside hole  31  of the second blocking member  30  before connection of the spacer member  40  to the second blocking member  30 . The second ball spring  61  imparts a downward pressure to the second ball  60  against the spacer member  40 , thereby causing the second ball  60  to block the axial through hole  42  of the spacer member  40 , i.e., the second ball spring  61  holds the second ball  60  in a fourth blocking position P 7  as shown in  FIG. 1  to block the passage between the inside hole  31  and the fluid inlet  14 . Further, the second ball  60  can be moved away from the fourth blocking position P 7  to a fourth opening position P 8  by upward flowing force of the fluid A as shown in  FIG. 8 .  
         [0027]     The control rod  70  is coupled to the link  73  by the coupling block  72 , and mounted with the coupling block  72  and the link  73  in the upper front fork tube  1   a . The link  73  extends upwardly to the outside of the upper front fork tube  1   a , and can be moved vertically up and down with the control rod  70  and the coupling block  71  by an external force. Because the driving method of the link  73  is not within the scope of the present invention, no further detailed description in this regard is necessary. As shown in  FIG. 1 , the guide rod  74  is provided at the bottom side of the coupling block  72  in parallel to the control rod  70 . When the bottom end of the control rod  70  entered the fluid inlet  14  and touched the second blocking member  30 , the guide rod  74  is inserted into the longitudinal through hole  17  of the casing  11  to guide axial movement of the control rod  70 . As shown in  FIG. 4 , the control rod  70  has a bottom notch  71  in the bottom side of the flat lower part thereof corresponding to the top through hole  32  of the second blocking member  30 . The control rod  70  can be alternatively set between an unlocking position P 9  as shown in  FIG. 1  and a locking position P 10  as shown in  FIG. 7 .  
         [0028]     The operation of the front fork shock-absorbing damper  100  is outlined hereinafter.  
         [0029]      FIG. 1  shows the standing status of the bicycle where the upper front fork tube  1   a  and the lower front fork tube  1   b  are not moved relative to each other. At this time, the first blocking member  20  is in the first blocking position P 1 , the second blocking member  30  is in the second opening position P 4 , the first ball  50  is in the third blocking position P 5 , and the fluid A is prohibited from passing through the main body  10 .  
         [0030]     When the upper front fork tube  1   a  is moving downwards relative to the lower front fork tube  1   b  during running of the bicycle as shown in  FIG. 5 , the fluid A below the main body  10  is forced to move the first blocking member  20  upwards to the first opening position P 2 . At this time, the first block member  20  does not block the transverse through holes  16 , and the fluid A is circulating through the fluid inlet  14  into the transverse through holes  16  toward the top side of the main body  10 . When the upper front fork tube  1   a  is moving upwards relative to the lower front fork tube  1   b  as shown in  FIG. 6 , a part of the fluid A above the main body  10  flows into the fluid inlet  14 , and the first spring member  25  is released, thereby causing the first blocking member  20  to be returned to the first blocking position P 1 . At the same time, a part of the fluid A flows through the neck  13  into the fluid outlet  15  to move the first ball  50  to the third opening position P 6 , and therefore the fluid A is allowed to pas to the bottom side of the main body  10 . By means of the aforesaid action, the fluid A is moving upwards and downwards through the main body  10  to absorb shocks during relative motion between the upper front fork tube  1   a  and the lower front fork tube  1   b.    
         [0031]     Further, the rider may control the front fork  1  not to provide a shock absorbing effect subject to the condition of the road. At this time, the rider can drives the link  73  to move the control rod  70  upwards to a locking position P 10  when the first blocking member  20  is in the first blocking position P 1  and the first ball  50  is in the third blocking position P 5  as shown in  FIG. 7 . At this time, the second spring member  33  pushes the second blocking member  30  upwards to the second blocking position P 3  to block the fluid inlet  14  of the main body  10 , and the second ball  60  is held by the second ball spring  61  to block the top through hole  42 , stopping the fluid A from passing through the main body  10 , and therefore the front fork shock-absorbing damper  100  does no work.  
         [0032]     If the bicycle unexpectedly moves over an uneven road surface (or a hole on the road) when the front fork shock-absorbing damper  100  set in the locking status, the first blocking member  20  will receive a sudden impact pressure from the fluid A. This sudden impact pressure is greater than the reactive force from the road surface against the bicycle, thereby causing the first blocking member  20  to be moved upwards to squeeze the fluid A as shown in  FIG. 8 . However, because the second blocking member  30  blocks the fluid inlet  14  at this time, the squeezed fluid A will move upwards through the top through hole  42  to push the second ball  60  to the fourth opening position P 8 , thereby causing the front fork shock-absorbing damper  100  to absorb shocks from the aforesaid sudden impact pressure.  
         [0033]     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.