Treadmill

Abstract

A treadmill includes a frame, two tracks, a wheel, two keels and two treads. The frame includes a front portion and a rear portion. The tracks are extended from the rear portion of the frame. The wheel is provided on the front portion of the frame. Each of the keels includes a front end connected to the wheel and a rear end movable on a related one of the tracks. Each of the treads is carried on a related one of the keels.

1 . A treadmill comprising:
 a frame comprising a front portion and a rear portion;   two tracks extended from the rear portion of the frame;   a wheel provided on the front portion of the frame;   two keels each comprising a front end connected to the wheel and a rear end movable on a related one of the tracks; and   two treads each carried on a related one of the keels.   
   
   
       2 . The treadmill according to  claim 1  comprising a post formed on the front portion of the frame, and the wheel is provided on the post. 
   
   
       3 . The treadmill according to  claim 1  comprising two cranks each comprising an end connected to the wheel and another end connected to the front end of a related one of the keels. 
   
   
       4 . The treadmill according to  claim 1  comprising:
 a resistance element provided on the frame behind the wheel; and   a belt wound around the wheel and the resistance element so that the resistance element provides adjustable resistance to the wheel during rotation.   
   
   
       5 . The treadmill according to  claim 4  wherein the resistance is selected from a group consisting of a magnetically controllable resistance element and a brake-belt resistance element. 
   
   
       6 . The treadmill according to  claim 1  wherein each of the keels comprises:
 two ears formed on the rear end thereof; and   a roller connected to the ears for rolling on and along a related one of the tracks.   
   
   
       7 . The treadmill according to  claim 6  wherein each of the tracks comprises a slot defined therein, and each of the keel comprises a pin inserted through the ears thereof and the slot of a related one of the tracks so that the roller thereof is retained on the related keel. 
   
   
       8 . The treadmill according to  claim 7  wherein each of the tracks comprises two ribs formed along two parallel edges of the slot thereof to enhance the strength thereof. 
   
   
       9 . The treadmill according to  claim 1  comprising a cane perpendicularly provided on the front portion of the frame to be held by a user. 
   
   
       10 . The treadmill according to  claim 9  wherein the cane is a telescopic cane comprising a lower tube perpendicularly provided on the front portion of the frame and an upper tube telescopically inserted in the lower tube. 
   
   
       11 . The treadmill according to  claim 10  comprising a length-adjusting device for adjusting the length of the telescopic cane. 
   
   
       12 . The treadmill according to  claim 11  wherein the length-adjusting device comprises:
 a screw hole defined in the lower tube;   a series of apertures defined in the upper tube; and   a threaded bolt for insertion in a selected one of the apertures through the screw hole.