Abstract:
An anti-lock braking system for bicycle connected to the chain stays and the front forks is cooperated with a disk. The characteristics of the brake system is that when the bicycle is stopped at high speed and an initial force is generated, when the initial force is larger than the spring forces in the brake system, the system generates a buffers the initial force so as to prevent the disk from being clamped overly. Therefore, the bicycle is under controlled when it brakes at high speed.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an anti-lock braking system (A.B.S.) for bicycle so as to buffer the initial force when the bicycle is stopped at high speed. 
     BACKGROUND OF THE INVENTION 
     A conventional disk brake system for bicycle is shown in FIG.  1  and generally includes an arm  1 , a clamp device  2  and a cable  3 . The disk type brake system has several benefits such as stable, brake precisely, good heat dispensing and can be used for a long period of time. Nevertheless, when the bicycle brakes at high speed, because the disk is clamped firmly so that the initial force of the bicycle pushes the bicycle forward still and the bicycle could shake or even the rider falls down from the bicycle. 
     The present invention intends to provide a disk type brake system wherein the initial force can be absorbed by deformation of springs and the disk can be loosened for only a very short period of time and is then clamped again. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide an anti-lock braking system for bicycle such that the initial force of the bicycle can be buffered. 
     Another object of the present invention is to provide an anti lock braking system for bicycle wherein the structure of the brake system is mechanical constructed and simple. 
     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 
     FIG. 1 is a plan view to show the conventional disk type brake system; 
     FIG. 1 is an exploded view to show the brake system of the present invention; 
     FIG. 3 is a plan view to show the brake system of the present invention; 
     FIG. 4 is a cross sectional view along the cutting line  4 — 4 ; 
     FIG. 5 shows that the brake system of the present invention is not operated; 
     FIG. 6 shows that the brake system of the present invention is operated; 
     FIGS. 7 and 8 show the disk is loosened and clamped within a short period of time, and 
     FIG. 9 shows an exploded view of another embodiment of the brake system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 2 to  4 , the brake system  5  of the present invention is connected to the chain stay or fort fork  6  of the bicycle and is cooperated with a disk  7 . The brake system comprises a main frame  10 , a fixing frame  20  and a brake mechanism  30 . 
     The main frame  10  is located at a side of the disk  7  and has a teethed inside  14 . Two grooves  15 ,  16  are defined in two sides of the main frame  10  and two springs  17 ,  18  are received in the two grooves  15 ,  16 . The two grooves  15 ,  16  each have a protrusion  19  such that an end of the spring  17 / 18  is engaged. 
     The fixing frame  20  includes a main portion  21  and two connection portions which are an upper connection portion  22  at one end and a lower connection portion  23  at the other end. The upper connection portion  22  is connected to the main frame  10  by an adjusting rod  24 . The lower connection portion  23  is connected to the main frame  10  by another adjusting rod  25 . Two threaded holes  26  are defined through the main portion  21  of the fixing frame  20  so that the fixing frame  20  is fixed to the chain stay or front fork  6  by bolts  27 . 
     The brake mechanism  30  is located onto the disk  7  and cooperated with the main frame  10  and the fixing frame  20 . The mechanism  30  includes a first brake arm  31 , a second brake arms  32 , a toothed cam  33 , a main shaft  34 , a cap  35 , a first lining plate  36 , a second lining plate  37  and a brake cable set  50 . 
     The first brake arm  31  and the second brake arm  32  are located on two sides of the disk  7 . A first hole  311  is defined in a predetermined location of the first brake arm  31  and a second hole  321  is defined in a predetermined location of the second brake arm  32 . A recess  312 / 322  is defined in a facing side of first brake arm  31  and the second brake arm  32 . A protrusion  313 / 323  extends from an inside of each of the recesses  312 ,  322  so that the other end of each of the two springs  17 ,  18  is engaged. Two lining strips  38  are received in each of the recesses  312 ,  322 . A recessed area  315  is defined in the side located in opposite to the side having the recess  312  in the first brake arm  31 . 
     The toothed cam  33  is located between the disk  7  and the first brake arm  31 . The toothed cam  33  has a central hole  331  and a plurality of teeth  332  so as to be engaged with the toothed inside  14  of the main frame  10 . The side facing the disk  7  of the toothed cam  33  has a plurality of tear-shaped notches  333  and each of the notches  333  includes a shallow end  334  and a deep end  335 . 
     The main shaft  34  is located between the disk  7  and the toothed cam  33 , and includes a plate portion  31  and a shaft  342  which extends from a side of the plate portion  31  and towards the first brake arm  31 . The shaft  342  extends through the central hole  331  in the toothed cam  33  and the first hole  311  in the first brake arm  31 . The plate portion  31  of the main shaft  34  has a plurality of beads  345  which are received in the tear-shaped notches  333 . A magnet  346  and an O-ring  347  are connected to the other side of the plate portion  341 . 
     The cap  35  is located between the disk  7  and the second brake arm  32 , and received in the second hole  321  of the second brake arm  32 . A side facing the disk  7  of the cap  35  has a magnet  351 . 
     The first lining plate  36  and the second lining plate  37  are located on two sides of the disk  7 . The. first lining plate  36  is located between the disk  7  and the main shaft  34 , and is located on the side of the plate portion  341  so as to be attracted by the magnet  346 . The second lining plate  37  is located between the cap  35  and the disk  7 . The second lining plate  37  is located on the side of the cap  36  such that it is attracted by the magnet  351 . 
     The brake cable set  50  is engaged with the recessed area  315  of the first brake arm  31  and includes an arm  51 , a brake cable  52 , a base  53 , a spring  54  and a cap  55 . The brake cable set  50  is well known in the art and will not be described in detailed. 
     Referring to FIGS. 5 to  8 , when the bicycle brakes at a high speed, the arm  51  of the brake cable set  50  is connected to the main shaft  34  of the brake mechanism  30  and rotated counter clockwise. The beads  345  of the main shaft  34  are moved from the deep ends  335  in the tear-shaped notches  333  to the shallow ends  334 . The beads  345  then protrude the main shaft  34  and toward the disk  7 . The first and second lining plates  36 ,  37  firmly clamp the disk  7  and the brake mechanism  30  and the main frame  10  are proceeding braking process on the fixing frame  20  as shown in FIGS. 5 and 6. 
     If an initial force of the high speed bicycle is larger than the forces of the springs  17 ,  18  in the main frame  10 , the brake system  5  proceeds a buffer action to prevent the disk  7  from being clamped overly by the brake system  5 . The initial force drives the brake mechanism  30  to move along the grooves  15 ,  16  of the main frame  10 , and the projections  313 ,  323  of the two brake arms  31 ,  32  compress the springs  17 ,  18 . At this moment, the teeth  332  of the toothed cam  33  are engaged with the toothed inside  14  of the main frame  10 , so that the toothed cam  33  is rotated counter clockwise. The tear-shaped notches  333  are shifted with the toothed can  33  and the beads  345  are moved back to the deep ends  335 . The main shaft  34  is not urged by the beads  345  and two lining plates  36 ,  37  are released suddenly as shown in FIG.  7 . 
     After a very short period of time such as five thousandth seconds, the initial force is less than the forces of the springs  17 ,  18 , the brake mechanism  30  pushes the mechanism  30  to its original position along the grooves  15 ,  16  in the main frame  10 . The toothed cam  33  is rotated clockwise and the tear-shaped notches  334  are rotated with the toothed cam  33  and the beads  345  move from the deep ends  335  to the shallow ends  333  to drive the main shaft  34 , and the two lining plates  36 ,  37  clamp the disks  7  firmly again as shown in FIG.  8 . By the arrangement, the disk  7  is not clamped overly by the lining plates  36 ,  37  and the affection by the initial force to the bicycle can be reduced. 
     Referring to FIG. 9, another preferred embodiment of brake system  98  is shown and includes a main frame  60  located at a side of the disk  7  and has a toothed inside  61 . Two grooves  62 ,  63  are defined in two sides of the main frame  60  and each have a spring  64  received therein. 
     A fixing frame  70  is connected to the chain stay or front fork  6  of the bicycle, and has two connection portions  71 ,  72  so as to be connected to the main frame  60 . 
     A brake mechanism  80  is operatively connected to the main frame  60  ad the fixing frame  70 , and includes two brake arms  81 ,  82  which are located on two sides of the disk  7 . Each brake arm  81 / 82  has a recess  811 / 812  on the facing side and located corresponding to the grooves  62 ,  63  of the main frame  60 . A toothed cam  83  is located between the disk  7  and the brake arm  81 . A plurality of teeth  831  are defined in the cam  83  so as to be engaged with the toothed inside  61  of the main frame  60 . A plurality of tear-shaped notches  832  are defined in the toothed cam  83 . A main shaft  84  is located between the disk  7  and the toothed cam  83 , and includes beads  841  so as to be received in the notches  832 . A cap  85  is located between the disk  7  and the brake arm  82 . Two lining plates  86 ,  87  are located on two sides of the disk  7  and located between the cap  85  and the main shaft  84 . A brake cable set  90  is connected to the brake arm  81  and includes an arm  91 , a brake cable  92 , a base  93 , a spring  94  and a dust cap  95 . 
     The relationship between parts of the above mentioned preferable embodiment is similar to the brake mechanism  5  described relative to FIGS. 2 to  8 , and will not be described in detailed here. The difference is that the grooves  62 ,  63  in the main frame  60  has a threaded hole  65  for a bolt  67  threadedly engaged. The two brake arms  81 ,  82  each have holes  812 ,  822  at predetermined positions so that bolts  813 ,  823  may extend. The springs  64  in the grooves  62 ,  63  each have hooks  641  at two ends thereof so that the hooks  641  on one end may hook on the bolt  67  and the hooks on the other end are hooked to the holes  812 ,  822  in the brake arms  81 ,  82 . By this arrangement, the brake mechanism  8  performs the same as the mechanism  5  mentioned above. 
     The brake mechanism has anti-lock braking feature to prevent the disk from being clamped overly by the operation of the toothed cam to release the beads to loosen the main shaft such that the lining plates release the disk. After the initial force is less than the forces of the springs, the brake mechanism is activated again to clamp the disk again. The brake feature is ensured and increases the safety of the rider. The mechanism is a mechanical arrangement which needs no complicated control devices and lines arrangements and can be done at low cost. 
     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.