BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to an exercising machine and, more specifically, to a stretching exerciser. 
   2. Description of the Related Art 
   A conventional stretching exerciser is known comprising a base, a leg extension bar located on the base, an upright extended upwardly backwards from the base, and a back cushion fixedly located on the top end of the upright. When in use, the user hook the legs on the leg extension bar and rest the back on the back cushion, and then alternatively bending the body backwardly downwards and lifting the head and the upper part of the body. 
   This design of stretching exerciser is not satisfactory in function. When the user is curving the body to stretch the muscles, the back cushion is not curved with the user&#39;s body to positively support the user&#39;s back, and the user&#39;s body may feel uncomfortable. Further, this design of stretching exercise can simply exercise the muscles of the user&#39;s back and abdomen. It is not practical to exercise the muscles of the other part of the body. 
   SUMMARY OF THE INVENTION 
   The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a stretching exerciser, which is safe and comfortable in use. 
   It is another object of the present invention to provide a stretching exerciser, which provides various operation modes for enabling the user to exercise the muscles of the whole body. 
   To achieve these objects of the present invention, the stretching exerciser comprises a base for positioning on the floor; a seat bar having a bottom end pivoted to the base and a top end; a back cushion fastened pivotally with the top end of the seat bar and forwardly backwardly turnable relative to the seat bar, the back cushion being closely attached to the seat bar due to the effect of the gravity weight thereof when receiving no external force; a seat mounted on the seat bar below the back cushion; and a spring bar for supporting the seat bar on the base in a backwardly tilted position, the spring bar having a bottom end coupled to the base and a top end coupled to the seat bar. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a stretching exerciser according to the present invention. 
       FIG. 2  is a schematic side view of the present invention, showing the adjustment of the positions of the back cushion and the base. 
       FIG. 3  is another schematic side view of the present invention, showing the receiving operation of the stretching exerciser. 
       FIG. 4  is a schematic drawing showing one application example of the present invention. 
       FIG. 5  is a schematic drawing showing another application example of the present invention. 
       FIG. 6  is a schematic drawing showing still another application example of the present invention. 
       FIG. 7  is a schematic drawing showing still another application example of the present invention. 
       FIG. 8  is a schematic drawing showing still another application example of the present invention. 
   


   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1 and 2 , a stretching exerciser in accordance with the present invention is shown comprised of a base  10 , a seat bar  20 , a back cushion  30 , a seat  40 , a spring bar  50 , and two elastic cord members  60 . 
   The base  10  is a substantially I-shaped framework comprising a front transverse bar  11 , a rear transverse bar  12 , and a longitudinal bar  13  connected between the front transverse bar  11  and the rear transverse bar  12 . According to the present preferred embodiment, the longitudinal bar  13  is a retractable rectangular bar so arranged that the front transverse bar  11  can be moved forwards/backwards relative to the rear transverse bar  12  (see the imaginary line shown in  FIG. 2 ) and then locked by a lock screw  14  at the retractable longitudinal bar  13 . An upright lug  15  is located on the longitudinal bar  13  at the top. Pulleys  16  are respectively provided at the ends of the front and rear transverse bars  11  and  12 . A leg extension bar  17  is provided at the front transverse bar  11 . 
   The seat bar  20  according to the present preferred embodiment is a retractable rectangular bar provided with a lock screw  25  at the right side for locking the seat bar  20  at the desired length. A pivot  21  is transversely extended through the bottom end of the seat bar  20  to pivotally secure the seat bar  20  to the upright lug  15 , for enabling the seat bar  20  to be turned back and forth relative to the base  10 . A first barrel  22  and a second barrel  23  are fixedly horizontally provided at the front side of the seat bar  20  at different elevations. An axle  26  is selectively and detachably inserted through the first barrel  22  or the second barrel  23 . A third barrel  24  is fixedly horizontally provided at the back side of the seat bar  20  above the elevation of the first barrel  22 , which is spaced above the second barrel  23 . 
   The back cushion  30  is a rectangular pad of soft material, having a back frame  31  pivotally fastened to the top end of the seat bar  20  with a pivot  32 . Therefore, the back cushion  30  can be turned relative to the seat bar  20  between a substantially vertical position (see the solid line shown in  FIG. 2 ) and a substantially horizontal position above the top end of the seat bar  20  (see the imaginary line shown in  FIG. 2 ). Due to the effect of the gravity weight, the back cushion  30  is normally supported on the seat bar  20  in the substantially vertical position. 
   The seat  40  comprises a seat pad  41  and two parallel seat frame bars  42  fixedly provided at the bottom side of the seat pad  41 . The rear ends of the seat frame bars  42  protrude over the rear side of the seat pad  41  and respectively pivotally connected to the two ends of the third barrel  24  by a pivot pin  43 , keeping the seat pad  41  at the front side of the seat bar  20  for sitting. The axle  26  is selectively and detachably inserted through the first barrel  22  or the second barrel  23  to support the seat frame bars  42  between two positions. 
   The spring bar  50  is adapted to support the seat bar  20  in a backwardly tilted position, having a bottom end fastened pivotally with the longitudinal bar  13  of the base  10  and a top end detachably pivotally fastened to the back side of the seat bar  20  by a lock pin  51 . 
   The two elastic cord members  60  are longitudinally provided at two sides of the base  10  and respectively extended through the pulleys  16 , each having two end pieces  61  at the respective two distal ends. Two loop handles  62  are respectively and detachably fastened to the front ends or rear ends of the elastic cord members  60  for the holding of the user&#39;s hands or the hooking of the user&#39;s legs. 
   Before use, the retractable longitudinal bar  13  and the retractable seat bar  20  are respectively adjusted to the desired length and then locked, so that the user can hook the legs on the leg extension bar  17  and rest the back on the back cushion  30  comfortably. When in use, the user can exercise the body in one of a variety of operation modes as outlined hereinafter. 
   1. As shown in  FIG. 4 , the user can rest the back on the back cushion  30  and hook the legs on the foot extension bar  17 , and then alternatively stretch and release the body to exercise the muscles of the back and the abdomen. 
   2. As shown in  FIG. 5 , the user can sit on the seat  40 , hook the legs on the leg extension bar  17 , and hold the loop handles  62  with the hands after the loop handles  62  have been respectively fastened to the end pieces at the rear ends of the elastic cord members  60 , and then pull the loop handles  62  forwardly upwards to stretch the elastic cord members  60 , so as to exercise the muscles of the shoulders and the arms. 
   3. As shown in  FIG. 6 , the user can sit on the seat  40  and hold the loop handles  62  with the hands after the loop handles  62  have been respectively fastened to the end pieces at the front ends of the elastic cord members  60 , and then pull the loop handles  62  upwards to stretch the elastic cord members  60 , so as to further exercise the muscles of the shoulders and the arms. 
   4. As shown in  FIG. 7 , the user can sit on the seat  40  and hook the legs on the loop handles  62  after the loop handles  62  have been respectively fastened to the end pieces at the front ends of the elastic cord members  60 , and then alternatively lift the legs to stretch the elastic cord members  60 , so as to further exercise the muscles of the legs. 
   5. As shown in  FIG. 8 , the user can stand on the rear transverse bar  12  of the base  10  and then pull the loop handles  62  upwards to stretch the elastic cord members  60  after the loop handles  62  have been respectively fastened to the end pieces at the rear ends of the elastic cord members  60 , so as to further exercise the muscles of the arms. 
   6. The user can also rest the back on the back cushion  30 , hook the legs on the leg extension bar  17 , and hold the loop handles  60  with the hands after the loop handles  62  have been respectively fastened to the end pieces at the rear ends of the elastic cord members  60 , and then simultaneously or alternatively lift the loop handles  62  to stretch the elastic cord members  60  when alternatively stretching and releasing the body, so as to exercise the muscles of the arms, the back, and the abdomen. 
   Further, the user can also rest the abdomen on the back cushion  30  and hold the leg extension bar  17  with the hands, and then perform push-and-pull to exercise the muscles of the arms and the chest. 
   When not in use, as shown in  FIG. 3 , the lock pin  51  is removed from the spring bar  50  and the seat bar  20 , and then the spring bar  50  and the seat bar  20  are turned downwards toward the base  10  to a received position in parallel to the base  10 , and then remove the axle  26  from the seat bar  20  for enabling the seat  40  to be turned to the received position in parallel to the collapsed seat bar  20 . 
   While only one embodiment of the invention has been shown and described, it will be understood that various modifications and changes could be made thereunto without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
A stretching exerciser includes a seat bar supported on a collapsible spring bar at a base in a backwardly tilted position. A back cushion is pivotally fastened with a top end of the seat bar and forwardly backwardly turnable relative to the seat bar. The back cushion is closely attached to the seat bar due to the effect of the gravity weight when receiving no external force. A seat is pivoted to the seat bar. An axle is adjustably mounted on a front side of seat bar to selectively support the seat between two elevational positions.