Abstract:
A height adjusting device for a bicycle seat post provides an up-down adjust unit. All the oil-flow control elements of the height adjusting device are arranged inside the up-down adjust unit. The oil flows between the valve port and the oil-block plate are blocked by both the oil-block plate and the valve port touching tightly in an up-down engaging manner. By the structure, what repairing the oil-flow control elements needs is to replace the up-down adjust unit when the oil-flow control elements are out of work. Therefore, it is convenient to repair and assemble. The valve port and the oil-block plate are arranged up and down so that they may touch each other closely in surfaces engaging. Thus, it provides good oil-blocking effects. Besides, the oil-block plate receives no shear stress occurring in the prior art generated from suddenly pressing down the seat. Therefore, it has a long service life.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a height adjusting device for a bicycle seat post and, more particularly, to a height adjusting device that not only provides a novel structure but also requires fewer elements and allows to be processed, repaired, and assembled easily. 
     Description of the Prior Art 
     Generally, a prior art height adjustment device of a bicycle seat post includes an inner tube, an outer tube, an up-down adjusting unit, and an up-down controlling unit. Wherein, the inner and outer tubes are inserted to each other. The up-down adjusting unit is positioned inside the inner and outer tubes. One end of the up-down adjusting unit is fastened to the outer tube, and the other end of the up-down adjusting unit is secured to the inner tube so as to direct the inner tube to move up or down. The up-down controlling unit, operated by a user, is used to manage the up-down adjusting unit to work or to stop. The prior art height adjustment devices of the bicycle seat post, as disclosed in Taiwan Patent 104205140 and 099137166 (hereafter, the prior art cases), are used to adjust the height of the bicycle seat post. The oil-flow control elements of the up-down adjusting units of the height adjustment devices disclosed in the prior art cases are arranged within both the inner and outer tubes, such that the prior art cases have the following deficiencies: 
     1. Inconvenient to Assemble and Repair: 
     The oil-flow control elements of the prior art up-down adjusting unit are configured inside both the inner and outer tubes, so the prior art up-down adjusting unit will use both space of the inner and outer tubes when working. Consequently, all the elements within the seat post need to be disassembled for repairing or replacing if the components are out of work. Hence, what it causes is not only inconvenient repairing but also inconvenient assembling. 
     2. Frail Oil-Block Ring: 
     As disclosed in the prior art cases, the outer side of the axle wears a hollow oil-block ring, and the hollow oil-block ring is secured to the axle after being worn on the axle. The oil flows are blocked by both the outer wall of the oil-block ring and the inner wall of the tube touching each other so as to prevent the oil of the first oil chamber separated by the oil-block ring from flowing into the second oil chamber. When the seat is adjusted down, there is a strong press-down force suddenly exerted on the seat post. Accordingly, the oil-block ring bears the shear stress from the sudden press-down movement, so it is easy to break. Furthermore, the oil-block ring may easily get thinner because the outer wall of the oil-block ring rubs the inner wall of the tube under long-time behavior of the shear-stress. Thus, it is easy to be worn to cause oil leakage problems and even out of work. 
     3. Higher Cost: 
     The oil flow control elements of the prior art cases are configured within the space of both the inner and outer tubes, such that the firing pin for pushing the oil-flow valve needs to be prolonged in length. Therefore, it may increase costs of pins. Besides, the prior art cases comprise many assemblies, and those assemblies may accumulate high standard deviation so that high precision of the assemblies is also required. In consequence, it may result in a high cost in assemblies processing. 
     It is against the background and the drawbacks associated therewith that the present invention has been developed. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to provide a height adjusting device for a bicycle seat post which not only provides a novel structure but also requires fewer elements and allows to be processed, repaired, and assembled easily. 
     The height adjusting device for a bicycle seat post disclosed in the present invention is characterized by the followings: the height adjusting device is provided with an up-down adjust unit, the oil-flow control elements of the height adjusting device are all arranged in the interior of the up-down adjust unit, and the valve port and the oil-block plate controlling the oil flows touch each other tightly in an up-down engaging manner. By virtue of the aforesaid structure, what repairing the oil-flow control elements needs is to replace the up-down adjust unit with a new one when the oil-flow control elements are out of work. Therefore, it is convenient to repair and assemble. The valve port and the oil-block plate are arranged up and down so as to touch each other closely in surfaces engaging, so that it has good oil-blocking effects. Besides, the oil-block plate does not receive a shear stress, occurring in the prior art, generated from suddenly pressing down the seat. Accordingly, it can provide a long service life. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the present invention may be more fully understood, a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which: 
         FIG. 1  is a stereogram of a preferred embodiment of the present invention. 
         FIG. 2  is a breakdown drawing of the preferred embodiment of the present invention. 
         FIG. 3  is a sectional view of the combination of the preferred embodiment of the present invention. 
         FIG. 4  to  FIG. 8  illustrate how the present invention works to adjust and locate the seat post height position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The means for achieving the aforesaid objective and the functions of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein a preferred embodiment of the present invention is disclosed. 
     Referring to  FIG. 1  to  FIG. 3 , a height adjusting device  1  for a bicycle seat post disclosed in the present invention includes an outer tube  10 , an inner tube  20 , an up-down adjust unit  30 , and an up-down control unit  40 . 
     The outer tube  10  has a bottom end inserted in a seat tube of a bicycle frame so as to allow the outer tube  10  to be secured to the seat tube. An inner wall of the bottom end of the outer tube  10  is provided with a first threaded surface  11 . An outer wall of a top end of the outer tube  10  is disposed with a head end  12 . 
     The inner tube  20  provides a bottom end inserted into an interior of the outer tube  10  from the top end of the outer tube  10 , and a top end arranged with a fixing base  21  for securing a bicycle seat. 
     After being combined together, the outer tube  10  and the inner tube  20  form a combination. The up-down adjust unit  30  is arranged inside the combination of the outer tube  10  and the inner tube  20 . Moreover, The up-down adjust unit  30  is provided with a first tube  31  and a second tube  32  inserted into the first tube  31 , wherein, the second tube  32  is shorter than the first tube  31 . An upper joining base  33  is disposed between a top-end opening of the first tube  31  and a top-end opening of the second tube  32  to combine the first tube  31  and the second tube  32 . A lower joining base  34  is fixed to a bottom-end opening of the first tube  31 . The upper joining base  33  may seal the top-end opening of the first tube  31 , and the lower joining base  34  may seal the bottom-end opening of the first tube  31 . The lower joining base  34  has an outer wall provided with a second threaded surface  341 , and the second threaded surface  341  is allowed to be screwed with the first threaded surface  11  of the outer tube  10  so as to be secured. The upper joining base  33  is arranged with an upper through hole  330  in the center thereof and the lower joining base  34  is also provided with a lower through hole  340  in the center thereof. The second tube  32  has a bottom end disposed with a valve base  35  allowing to seal a bottom-end opening of the second tube  32 . The valve base  35  provides an eccentric position arranged with a plurality of axial valve ports  350 , and a center provided with a center through hole  351  arranged axially. The up-down adjust unit  30  also includes an axle rod  36  and a firing pin  37 . The axle rod  36  has a bottom end configured with a piston  360 . The piston  360  is inside the second tube  32 . An outer wall of the piston  360  touches an inner wall of the second tube  32 . The axle rod  36  has a top end which may stay within the inner tube  20  after passing through the upper through hole  330 . Moreover, the top end of the axle rod  36  is disposed with a coupling base  361  fastened with the fixing base  21  so as to allow the axle rod  36  and the inner tube  20  to axially move simultaneously. The firing pin  37  provides an top end whose outer side is arranged with an oil-block plate  370  formed by glue bonding a metal plate  370   a  and a rubber plate  370   b  together, as shown in  FIG. 4  and  FIG. 6 , wherein the rubber plate  370   b  faces the valve port  350 . The oil-block plate  370  may stay on top of the valve base  35  after the top end of the firing pin  37  passes through the center through hole  351  of the valve base  35 , so that the oil-block plate  370  and the valve port  350  are arranged up and down. The oil-block plate  370  is large enough in diameter to cover and block the plurality of valve ports  350 . The firing pin  37  is pushed downwards by an elastic element  371  inside the valve base  35  so as to allow the oil-block plate  370  to block the valve port  350  in a normal state. The firing pin  37  has a bottom end provided with a pushing surface  372  allowing to pass through a lower through hole  340  of the lower joining base  34  to the position under the lower joining base  34 . An outer side of a middle section of the firing pin  37  within the first tube  31  is arranged with a floating piston  373  which may axially move along the firing pin  37  after being pushed. The floating piston  373  provides an outer wall touching an inner wall of the first tube  31 . A first oil chamber  374  whose interior is filled with oil is arranged inside the second tube  32  and between the piston  360  and the upper joining base  33 . A second oil chamber  375  whose interior is filled with oil is also arranged inside the second tube  32  and between the piston  360  and the valve base  35 . A third oil chamber  376  whose interior is filled with oil is arranged inside the first tube  31  and in a space formed among the valve base  35 , the floating piston  373 , and an outer wall of the second tube  32 . An air chamber  377  whose interior is filled with air is arranged inside the first tube  31  and between the floating piston  373  and the lower joining base  34 . An outer wall of a top end of the second tube  32  is provided with a plurality of oil through holes  320  to allow oil within the third oil chamber  376  to flow into the first oil chamber  374  via the oil through holes  320  when the oil inside the third oil chamber  376  is squeezed. 
     The up-down control unit  40 , being arranged under the pushing surface  372  of the firing pin  37 , provides a control arm  41 . The control arm  41  has an end disposed with a pivot hole  42  allowing a pivot pin  43  to pass through, and an opposite end, opposite to the position of the pivot hole  42  is configured, arranged with an insertion groove  44 . Wherein the pivot pin  43  is pivotally connected with a fasten hole  342  at an eccentric position of the lower joining base  34  so as to pivotally connect the control arm  41  with the lower joining base  34 . Moreover, the insertion groove  44 , whose center is provided with a wire hole  440 , has an opening whose backside faces the pushing surface  372 . The outer wall of the lower joining base  34  corresponding to the wire hole  440  is configured with a concave wire-head hole  343 . The insertion groove  44  allows an end of a protecting tube  51  to insert into, wherein the protecting tube  51  is arranged outside of a controlling wire  50  and allows the controlling wire  50  to pass through. The wire hole  440  allows a first end of the controlling wire  50  to pass through. A controlling-wire head  52  of the first end of the controlling wire  50  is inserted into the wire-head hole  343  to be secured. The side of the control arm  41  facing the pushing surface  372  is arranged with a protruding push-up member  45  aligning the pushing surface  372 . When the controlling wire  50  of the bicycle handlebar is pulled, the control arm  41  is driven to take the pivot pin  43  as the pivot point to eccentrically move towards the firing pin  37  so as to direct the push-up member  45  to push the pushing surface  372  up to actuate the firing pin  37  to simultaneously axially move upwards to cause the oil-block plate  370  to move away from the valve port  350 . 
     According to a preferred embodiment of the present invention, the aforesaid assemblies are allowed to be assembled together to form a combination shown in FIG.  1  and  FIG. 3 . When employed, the combination of the up-down adjust unit  30  and the up-down control unit  40  can also be arranged inside the outer tube  10  and the inner tube  20  in an inverted manner without being limited by the manner employed in  FIG. 1  and  FIG. 3 . 
     Referring to  FIG. 4 , if the seat height needs to be adjusted higher, a user has to pull a second end of the controlling wire  50  at the bicycle handlebar (the second end is opposite to the first end of the controlling wire  50 ). Accordingly, the protecting tube  51  at the first end of the controlling wire  50  is pushed to direct the end of the protecting tube  51  to drive the control arm  41  to take the pivot pin  43  as the pivot point to turn pivotally to actuate the push-up member  45  to push the pushing surface  372  and the firing pin  37  up to press the elastic element  371  so as to allow the firing pin  37  to axially move upwards to cause the oil-block plate  370  to move away from the valve port  350  to enable the second oil chamber  375  and the third oil chamber  376  to communicate with each other. At this moment, don&#39;t press the seat. The floating piston  373  is pushed by the air pressure within the air chamber  377  to axially move upwards to squeeze the oil inside the third oil chamber  376  to reversely flow through the valve port  350  into the second oil chamber  375  to push the piston  360 , the axle rod  36  and the inner tube  20  up. Besides, the oil of the first oil chamber  374  is squeezed upwards by the piston  360  to flow into the third oil chamber  376  via the oil through hole  320 . Thus, the seat can be adjusted higher. Referring to  FIG. 5 , when the seat raises to a desired height, the user needs to release the controlling wire  50 . Then, the end of the protecting tube  51  stops pushing the push-up member  45  of the control arm  41  so that the push-up member  45  stops pushing the firing pin  37 . Consequently, the firing pin  37  is pushed back to its home position by the elastic element  371  to cause the oil-block plate  370  to block the valve port  350  to stop the oil flowing so as to locate the seat height position. 
     If the seat height needs to be adjusted lower, the second end of the controlling wire  50  of the bicycle handlebar needs to be pulled. Thus, the protecting tube  51  of the first end of the controlling wire  50  is driven to actuate the control arm  41  to take the pivot pin  43  as the pivot point to turn pivotally to direct the push-up member  45  to push the pushing surface  372  and the firing pin  37  up to axially move upwards to cause the oil-block plate  370  to move away from the valve port  350  to enable the second oil chamber  375  and the third oil chamber  376  to communicate with each other, as shown in  FIG. 6 . At this moment, the user needs to exert a force on the seat to press down the axle rod  36  and the inner tube  20 , as shown in  FIG. 7 . The oil within the second oil chamber  375  is squeezed by the piston  360  to flow through the valve port  350  into the third oil chamber  376 . With the down-press movement of the axle rod  36  and the piston  360 , part of oil inside the second oil chamber  375  may flow into the first oil chamber  374  via the oil through holes  320 . Because the axle rod  36  inserts into the second tube  32 , it occupies some inner space of the first oil chamber  374  and causes the first oil chamber  374  and the second oil chamber  375  do not have enough space to accommodate the oil completely. Thus, the oil flowing into the third oil chamber  376  accumulates pressure to push the floating piston  373  to move downwards to squeeze the air within the air chamber  377 . When the air pressure accumulated in the air chamber  377  is equal to the oil pressure of the third oil chamber  376 , the axle rod  36  and the inner tube  20  are not allowed to move down any more. That is the lowest position the seat can reach. After the seat is lowered to a desired height, the controlling wire  50  needs to be released. Then, the firing pin  37  and the oil-block plate  370  are immediately pushed back to their home positions by the restoring force of the elastic element  371  to drive the oil-block plate  370  to block the valve port  350 . Thus, the oil in the second oil chamber  375  and in the third oil chamber  376  may stop flowing so as to fix the seat height position after adjusted, as shown in  FIG. 8 . 
     The aforesaid oil flows are all arranged and managed inside the up-down adjust unit  30 , that is, the up-down adjust unit  30  can be regarded as a closed type, so that the whole up-down adjust unit  30  is allowed to be replaced with a new one adjust unit  30  when the oil-flow control elements break down or need assembling together. Therefore, it is convenient to repair and assemble. 
     As the mentioned, the oil-block plate  370  and the valve port  350  are arranged up and down such that they may touch each other tightly in an up-down engaging manner to block the oil flows between the oil-block plate  370  of the up-down adjust unit  30  and the valve port  350 . Accordingly, the oil-block plate  370  will not receive the shear stress generated from suddenly pressing down the seat when the seat height is adjusted, so as to have a long service life. 
     The aforesaid structure is novel and requires fewer elements, so that it may reduce not only working hours but also cost in processing and assembling. 
     It will be appreciated by those skilled in the art that variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.