Structure for extendable bicycles

Abstract

An improved structure for expandable bicycles to facilitate storing of a bicycle includes a cross bar which has one end fastened to the front fork of the bicycle and a sliding member slidable horizontally on the cross bar to alter the relative position of the front fork and the rear fork. The sliding member has a fastening member to fasten the head and seat of the bicycle on selected locations. Thus the bicycle may be extended as desired and stored conveniently.

1 . An improved structure for expandable bicycles for use on a main frame of a bicycle to extend or retract the bicycle by altering the relative position of a bicycle head, comprising: 
 at least one cross bar which is a portion of the main frame for supporting and coupling all other elements of the bicycle having a first fastening dock on a front side and a second fastening dock on a rear side, the first fastening dock having a first bore for installing a front fork;    a sliding member having a second bore on side walls thereof to allow the cross bar to run through and slide therein, a third bore on a top side to install a rear fork, and a first fastening hole; and    a fastening member including a fastening plate and a fastening rod, the fastening plate being coupled with the sliding member through the first fastening hole, the fastening plate having a second fastening hole corresponding to the first fastening hole to install the fastening rod.    
   
   
       2 . The improved structure for expandable bicycles of  claim 1  further having an elastic element located on the juncture of the cross bar and each fastening dock to absorb impact when the sliding member slides on the cross bar.  
   
   
       3 . The improved structure for expandable bicycles of  claim 2 , wherein the elastic element is a soft pad or a spring.  
   
   
       4 . The improved structure for expandable bicycles of  claim 1 , wherein the first fastening dock and the second fastening dock have respectively a fourth bore and a fifth bore on a side wall thereof to couple with the cross bar for fastening.  
   
   
       5 . The improved structure for expandable bicycles of  claim 1 , wherein the cross bar is fastened to the fastening dock through a fastening element.  
   
   
       6 . The improved structure for expandable bicycles of  claim 5 , wherein the fastening element is a screw or an anchor nail.  
   
   
       7 . The improved structure for expandable bicycles of  claim 5 , wherein the fastening docks have a third fastening hole.  
   
   
       8 . The improved structure for expandable bicycles of  claim 1 , wherein the sliding member has a trough mating the fastening plate to couple with the fastening plate.  
   
   
       9 . The improved structure for expandable bicycles of  claim 1 , wherein the fastening plate has a recess mating the cross bar run through the sliding member.  
   
   
       10 . The improved structure for expandable bicycles of  claim 1 , wherein the fastening rod has a coupling section on the bottom thereof to fasten the fastening plate, the cross bar and the sliding member and close gaps formed therebetween to anchor the sliding member on a desired location.  
   
   
       11 . The improved structure for expandable bicycles of  claim 10 , wherein the coupling section is a bolt or a latch tenon.  
   
   
       12 . The improved structure for expandable bicycles of  claim 1 , wherein the fastening rod has a cam on the top end thereof which is eccentric to fasten the fastening plate, the cross bar and the sliding member tightly.  
   
   
       13 . The improved structure for expandable bicycles of  claim 1 , wherein the second bore has two openings on two sides to hold respectively a ball bearing or a roller to facilitate sliding of the cross bar.