Abstract:
A backrest-adjusting device for a bicycle is specially designed for persons who are handicapped or try to rectify the body, including a backrest adjusting set and a breast-support adjusting set for securing a rider on a bicycle stably by adjusting the position of the backrest and the waist pad and the torso supports according to the rider&#39;s body size. Then the rider can be protected from falling down to get wounded or injured, safely using the bicycle.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a backrest adjusting device for a bicycle, particularly to one specially suitable for the handicapped or limb rectifiers with rectifying functions for sitting postures of a user (rider) on the bicycle and preventing the user from falling down, extremely safe for using. 
   2. Description of the Prior Art 
   A conventional backrest for a bicycle shown in  FIG. 16  includes a frame  31 , a headrest  32  fixed on top of the frame  31 , two breast-clamp rods  33  provided at two sides of the frame  31  and facing to each other, and a U-shaped waist clamp rod fixed with the frame  31 , and a connector  35  connecting the lower end of the frame  31  with the bicycle frame. 
   In using, a rider has the head resting on the headrest  32 , the breast and the waist secured by the breast clamp rods  33  and the waist clamp rod  34  so that the rider may not fall off the bicycle to get wounded or injured. 
   However, the conventional bicycle backrest is not provided with a backrest, but with a headrest and the breast and the waist clamp rod(s), so it is not so comfortable as it seems without any elastic means for the body of a rider to feel comfortableness. 
   SUMMARY OF THE INVENTION 
   The backrest adjusting device for a bicycle in the invention is designed for specially handicapped persons or persons who try to rectify their bodies, including a backrest adjusting set and a torso-support adjusting set to secure a rider stably on the bicycle without possibility of falling down to get wounded or injured, and to give medical treatment function for a body-rectifier with safety in use 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     This invention will be better understood by referring to the accompanying drawings, wherein; 
       FIG. 1  is a perspective view of a bicycle with a backrest-adjusting device in the present invention; 
       FIG. 2  is a perspective view of the backrest-adjusting device separated from a bicycle in the present invention; 
       FIG. 3  is an exploded perspective view of the backrest-adjusting device in the present invention; 
       FIG. 4  is an exploded perspective view of a backrest-adjusting unit in the present invention; 
       FIG. 5  is an exploded perspective view of a torso-support unit in the present invention; 
       FIG. 6  is a cross-sectional view of a sleeve of a backrest-adjusting unit being adjusted in one way in the present invention; 
       FIG. 7  is a cross-sectional view of the sleeve of the backrest-adjusting unit being adjusted in another way in the present invention; 
       FIG. 8  is a side view of the backrest-adjusting unit being adjusted in one way in the present invention; 
       FIG. 9  is a side view of the backrest-adjusting unit being adjusted in another way in the present invention; 
       FIG. 10  is a side cross-sectional view of a torso-support unit being adjusted in one way in the present invention; 
       FIG. 11  is a side cross-sectional view of the torso-support unit being adjusted in another way in the present invention; 
       FIG. 12  is a partial magnified view of the torso-support unit in the present invention; 
       FIG. 13  is a side cross-sectional view of the torso-support unit being adjusted in one way in the present invention; 
       FIG. 14  is a side cross-sectional view of the torso-support unit being adjusted in another way in the present invention; 
       FIG. 15  is another partial magnified side cross-sectional view of the torso-support unit in the present invention; and, 
       FIG. 16  is a perspective view of a conventional backrest-adjusting device fixed on a bicycle. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A preferred embodiment of a backrest-adjusting device (A) for a bicycle in the present invention, as shown in  FIGS. 1 ,  2  and  3 , includes a backrest adjusting set  1  and two torso-support sets  2  arranged on a frame rod (A 1 ). 
   The backrest adjusting set  1  consists of a backrest-adjusting unit  10  and a waist-pad-adjusting unit  11 . 
   The backrest adjusting unit  10  has a backrest board  101 , two cylinders  1011  respectively fixed at two vertical sides of the backrest board  101  and fitting movably around the frame rod (A 1 ), a sleeve  1012  fixed at an outer side of each cylinder  1011  for combining with the torso-support unit  11 . The backrest board  101  has plural screw holes  1013  for screws  1021  of a backrest  102  to engage with, two spaced-apart upper position ears  1014  and two spaced-apart lower position ears  1015  on an inner surface. The lower position ears  1015  have a hole for a bolt  103  to fit through for pivotally connecting an activating rod  104 , which has a pivotal rod  106  fitted in an upper end, and a spring  105  fits around the pivotal rod  106 , and then a pin  107  passes through the outer end of the pivotal rod  106  and the two upper position ears  1014  of the backrest board  101  to secure the activating rod  104  with the backrest board  101 . 
   The waist-pad adjusting unit  11  has a waist-pad board  111  provided with screw holes  1110  for screws  1121  of a waist pad  112  to engage with for securing the waist pad  112  with the waist-pad board  111 . The waist-pad board  111  further has two part-threaded rods  1111  extending laterally from the inner surface to pass through a position base  11 , with a spring  113  fitting around each of the rods  1111 , and then the position base  11  has a square sleeve  1141  for the square activating rod  104  to fit in movably. Thus the springs  113  have its front end pushing against the rear side of the waist-pad  112  and its rear end pushing against the front side of the position base  114 . 
   Further, referring to  FIG. 5 , the two torso-support sets  2  respectively have an insert rod  21  inserting in each cylinders  1011  of the backrest board  101 , a connector  22  fixed with an intermediate portion of each insert rod  21 , a protective pad  23  connected to another connector  22  provided with two screw holes  221 . The two connectors  22  both have a groove  222  in an inner side for one end of a protective band  24  to fit therein. The protective band  24  has a long slide slot  241  in the left portion and two slide slots  241  in the right portion for screws  223  engaging with the screw holes  221  to fit and slide therein. 
   In using, referring to  FIGS. 6 ,  7 ,  8 , and  9 , firstly the cylinders  1011  are fitted around the frame rod (A 1 ), which has an elastic projection (A 2 ) fitting out of one of position holes  1011   a  to secure the cylinder  1011  at the position. Then when the elastic projection (A 2 ) is pressed into the cylinder  1011  through that of the position holes  1011   a , the cylinders  1011  can freely move up and down along the frame rod (A 1 ) to change its locations relative to the frame rod (A 1 ) so as to adjust the locations of the backrest adjusting unit  10  and the breast-support unit  11 . After the cylinders  1011  are moved to a best wanted position for the back of a rider to rest on, the waist-support adjusting unit  11  can be adjusted for the waist of the rider to rest against, by moving the position base  114  up or down along the activating rod  104  to let the waist pad  112  moved to suit to the waist of the rider. As the activating rod  104  is pivotally connected to the lower position ears  1015 , which can control the spring  105  pivotally connected to the upper ears  1014  to lengthen or shrink to secure movably the activating rod  104  together the position base  11 , the activating rod  114  can seesaw with the bolt  103  function as a fulcrum. In addition, the spring  105  can keep the backrest  102  elastically supported, and the two springs  113  can keep the waist pad  112  elastically supported, so that the rider can rest comfortably on the backrest  102  and the waist pad  112  with the resiliency of the springs  105  and  113 . 
   After the backrest  102  and the waist pad  112  are adjusted, the two torso-support adjusting sets  2  are to be handled, referring to  FIGS. 10 ,  11 ,  12 ,  13 ,  14  and  15 . The torso-support adjusting sets  2  respectively have the insert rod  21  fitting in the two sleeves  1012  of the backrest board  101  and secured by a constrictor (B) stably. Then the protective pads  23  are moved inward or outward relative to the protective band  24 , with the screws  223  sliding along the slide slots  241  so as to let the protective pads  23  may lightly contact the two sides of the breast of the rider for protection, as different persons have different sizes of their breast. Then the screws  223  are tightened to keep immovable the protective pads  23  at that adjusted position, finishing the adjusting work of the torso-support adjusting sets  2 . 
   The backrest-adjusting device for a bicycle in the invention has the following advantages as can be understood from the foresaid description.
     1. The backrest adjusting set and the torso-support adjusting set can keep stably an especially handicapped rider or a body rectifier so as to prevent the rider from falling down.   2. The back, the waist and the torso of a rider can be all protected by adjusting the backrest-adjusting unit, the waist pad adjusting unit and the torso-support adjusting set, enabling the rider ride on the bicycle with comfortableness and safety.   

   While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.