Abdominal exercising machine

Abstract

An abdominal exercising machine is constructed to include a machine base formed of a first frame and a second frame axially adjustably fastened together, a footplate mounted on the second frame at the top for the resting of the user's feet, a seat fixedly mounted on the first frame for the user to sit, a back support, the back support having a first supporting frame pivoted to the first frame and holding a lower back cushion and a second supporting frame hinged to the first supporting frame and holding an upper back cushion, two handlebars symmetrically extended from the second supporting frame for the holding of the user's hands, and a damping device coupled between the first supporting frame of the back support and the first frame of the machine base.

What is claimed is:  
     
         1 . An abdominal exercising machine comprising: 
 a machine base provided with a first frame and a second frame, said first frame and said second frame having a respective rear end coupled to each other;    a footplate mounted on a top side of said second frame of said machine base for the resting of the user's feet;    a seat fixedly mounted on the first frame of said machine base for the user to sit;    a back support, said back support comprising a first supporting frame pivoted to said first frame of said machine base, a lower back cushion fixedly mounted on said first supporting frame, a second supporting frame pivoted to a top end of said first supporting frame, and an upper back cushion fixedly mounted on said second supporting frame;    two handlebars symmetrically extended from said second supporting frame of said back support for the holding of the user's hands; and    a damping device coupled between said first supporting frame of said back support and said first frame of said machine base.    
     
     
         2 . The abdominal exercising machine as claimed in  claim 1  wherein said first frame of said machine base comprises a tubular rear end adapted to receive a part of said second frame and a lock screw mounted in said tubular rear end and adapted to lock the inserted part of said second frame; said second frame of said machine base has a rear end insertable in the tubular rear end of said first frame and a longitudinal series of locating holes disposed in the rear end and selectively fastened to the lock screw of said first frame.  
     
     
         3 . The abdominal exercising machine as claimed in  claim 1  wherein said seat comprises a seat frame fixedly fastened to said first frame of said machine base, and a seat cushion fixedly mounted on a top side of said seat frame.  
     
     
         4 . The abdominal exercising machine as claimed in  claim 1  wherein said first frame of said machine base has a lug, and the first supporting frame of said back support is pivoted to said lug of said first frame of said machine base.  
     
     
         5 . The abdominal exercising machine as claimed in  claim 1  wherein said first supporting frame is provided at the top end thereof with a hinge, and said second supporting frame is connected to said hinge.  
     
     
         6 . The abdominal exercising machine as claimed in  claim 1  wherein said handlebars each have a rear end fixedly covered with a flexible handgrip.  
     
     
         7 . The abdominal exercising machine as claimed in  claim 1  further comprising an elastic member connected between said first supporting frame of said back support and said first frame of said machine base.  
     
     
         8 . The abdominal exercising machine as claimed in  claim 7  wherein said elastic member is an elastic band.  
     
     
         9 . The abdominal exercising machine as claimed in  claim 7  wherein said elastic member is a spring.