Patent Publication Number: US-2012027510-A1

Title: Seat post assembly

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a seat post assembly, and more particularly to a seat post assembly for effectively refraining an inner tube from rotation relative to an outer tube. 
     2. Description of Related Art 
     Cycling has become an extremely popular recreational activity throughout the world in recent decades. As more and more people indulge themselves in cycling, a demand for innovation and improvement of bicycles and bicycle parts has arisen. 
     A conventional seat post assembly includes an elongated tubular housing. A sleeve is received in the tubular housing. A shock-absorbing device includes a resilient unit disposed in the tubular housing. The resilient unit includes a first coil spring and a second coil spring respectively abutting against the sleeve. Thereby, via the first coil spring and the second coil spring, a shock-absorbing effect is provided during riding. 
     However, despite the effects it provides, the conventional seat post assembly has the following drawbacks: for instance, the sleeve is received in the elongated tubular housing, but the sleeve is easily rotated relative to the elongated tubular housing during riding. When the sleeve is rotated relative to the elongated tubular housing, the shock-absorbing effect is reduced. To overcome this drawback, a non-rotary sleeve is provided to prevent the sleeve from rotating relative to the elongated tubular housing. However, the sleeve may gradually wear through continuous use, when the sleeve is worn, the sleeve will still rotate relative to the elongated tubular housing during operation. 
     The present invention has arisen to obviate/mitigate the disadvantages of the conventional seat post assembly. 
     SUMMARY OF THE INVENTION 
     The main objective of the present invention is to provide a seat post assembly which overcomes the disadvantages of the conventional seat post assembly. 
     To achieve the objective, the seat post assembly in accordance with the present invention comprises a saddle positioning unit which is adapted to be mounted to a saddle. An outer tube has one end connected to the saddle positioning unit. An inner tube is received in the outer tube. The inner tube has a non-circular outer periphery. An opening is laterally defined in the outer periphery of the inner tube and communicated with an interior of the inner tube. An inner post passes through the inner tube and is received in the outer tube for engaging with the saddle positioning unit. The inner post has a recess laterally defined in one end thereof for corresponding to the opening of the inner tube. The recess has two inclined inner walls oppositely and respectively formed on two sides thereof. An abutting member is disposed in the recess. The abutting member has a surface contacting with an inner peripheral wall of the outer tube, the surface is formed with a tapered shape. An assisting member is sandwiched between the abutting member and a bottom of the recess such that the assisting member is correspondingly received in the recess. A hardness of the assisting member is greater than that of the abutting member. A tightening unit radially passes through the outer tube, the inner tube, and the inner post for abutting against the assisting member for consequently pushing the abutting member such that the abutting member tightly/loosely abuts against the inner peripheral wall of the outer tube. 
     The assisting member and the abutting member are substantially trapezoidal shaped for corresponding to the two inclined inner walls of the recess such that the assisting member and the abutting member are slightly movable within the recess. 
     By adjusting the tightening unit, the abutting member tightly/loosely abuts against the inner peripheral wall of the outer tube for refraining the inner tube from rotating relative to the outer tube. 
     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 an assembled perspective view of the seat post assembly in accordance with the present invention; 
         FIG. 2  is an exploded perspective view of the seat post assembly in accordance with the present invention; 
         FIG. 3  is an operational cross-sectional view of the seat post assembly in accordance with the present invention; and 
         FIG. 4  is another operational cross-sectional view of the seat post assembly in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings and initially to  FIGS. 1-2 , the seat post assembly in accordance with the present invention comprises a saddle positioning unit  4  adapted to be mounted to a saddle (not shown). An outer tube  1  has one end connected to the saddle positioning unit  4 . An inner tube  2  is coaxially received in the outer tube  1 . As shown in  FIG. 2 , the inner tube  2  has a hexagonal outer periphery. An opening  21  is laterally defined in the outer periphery of the inner tube  2  and communicated with an interior of the inner tube  2 . In the present embodiment, a shock-absorbing device (not numbered) is installed in the outer tube  1  for providing a shock-absorbing effect (Structures and functions of the shock-absorbing device are well-known in the art, and are not the objectives of the present invention, therefore, only brief description is provided). An inner post  3  passes through the inner tube  2  and is coaxially received in the outer tube  1  for engaging with the saddle positioning unit  4 . The inner post  3  has a recess  31  laterally defined in one end thereof for corresponding to the opening  21  of the inner tube  2 . The recess  31  has two inclined inner walls  311  oppositely and respectively formed on two sides thereof. An abutting member  5  is disposed in the recess  31 . An assisting member  51  is sandwiched between the abutting member  5  and a bottom of the recess  31  such that the assisting member  5  is correspondingly received in the recess  31 . The assisting member  51  and the abutting member  5  are substantially trapezoidal shaped for corresponding to the two inclined inner walls  311  such that the assisting member  51  and the abutting member  5  are slightly movable within the recess  31 . In the preferred embodiment, the abutting member  5  is consisted of plastic, and the assisting member  51  is consisted of metal such that a hardness of the assisting member  51  is greater than that of the abutting member  5 . The abutting member  5  has a surface contacting with the inner peripheral wall of the outer tube  1 , as shown in  FIG. 2 , the surface is formed with a tapered shape which corresponds to the hexagonal outer periphery of the inner tube  2 . 
     Each of the outer tube  1 , the inner tube  2 , and the inner post  3  has a through hole  11 ,  23 ,  32  radially defined in outer periphery thereof. As shown in  FIG. 2 , the through hole  23  of the inner tube  2  is oppositely located relative to the opening  21 . When the outer tube  1 , the inner tube  2 , and the inner post  3  are assembled, the through holes  11 ,  23 ,  32  are communicated with each other. A tightening unit  22  radially and sequentially passes through the through holes  11 ,  23 ,  32  of outer tube  1 , the inner tube  2 , and the inner post  3 . In the present embodiment, the through holes  11 ,  23 ,  32  are threaded holes and the tightening unit  22  is a threaded member such that the tightening unit  22  adjustably and threadedly passes through the through holes  11 ,  23 ,  32  and abuts against the assisting member  51  for pushing the abutting member  5  to abut against the inner peripheral wall of the outer tube  1 . As previously described, the assisting member  51  is consisted of metal and the abutting member  5  is consisted of plastic, such that the assisting member  51  is durable against a force exerted thereon by said tightening unit  22 ; whereas the plastic-made abutting member  5  elastically abuts against the inner peripheral wall of the outer tube  1  when the abutting member  5  is pushed by the assisting member  51 . Therefore, when the tightening unit  22  abuts against the assisting member  51 , the tightening unit  5  consequently and readily pushes the abutting member  5  to abut against the inner peripheral wall of the outer tube  1 . 
     Further referring to  FIGS. 3-4 , operation of the seat post assembly in accordance with the present invention will be described in detailed below. By adjusting the tightening unit  22 , the abutting member  5  tightly or loosely abuts against the inner peripheral wall of the outer tube  1 . As shown in  FIG. 4 , the tightening unit  22  is threadedly adjusted and abuts against the assisting member  51 , such that the abutting member  5  is pushed to tightly abut against the inner peripheral wall of the outer tube  1  for enhancedly refraining the inner tube  2  from rotation relative to the outer tube  1 . 
     Although the invention has been explained in relations to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.