Treadmill

Abstract

A treadmill includes a caterpillar track includes two belts, planks, caster-supporting elements, and casters. Each of the belts is a loop. Each of planks includes two terminal sections each of which is connected to an external face of a corresponding one of the belts. Each of the caster-supporting elements is connected to an internal face of a corresponding one of the belts. Each of the belts includes sections each of which is sandwiched between a corresponding one of the terminal sections of a corresponding one of the planks and a corresponding one of the caster-supporting elements. The casters are supported by the caster-supporting elements.

1 . A treadmill comprising a caterpillar track comprising:
 two belts in the form of a loop so that each of the belts comprises an internal face and an external face;   planks each of which comprises two terminal sections each of which is connected to the external face of a corresponding one of the belts;   caster-supporting elements each of which is connected to the internal face of a corresponding one of the belts, wherein each of the belts comprises sections each of which is sandwiched between a corresponding one of the terminal sections of a corresponding one of the planks and a corresponding one of the caster-supporting elements; and   casters supported by the caster-supporting elements.   
     
     
         2 . The treadmill according to  claim 1 , wherein each of the caster-supporting elements comprises:
 a top portion in contact with the internal face of the corresponding one of the belts while each of the planks is in contact with the external face of the corresponding one of the belts; and   a wall extending from the top portion, wherein the wall supports a corresponding one of the casters.   
     
     
         3 . The treadmill according to  claim 2 , wherein each of the caster-supporting elements comprises two reinforcing portions each of which comprises a portion connected to the top portion and another portion connected to the wall. 
     
     
         4 . The treadmill according to  claim 2 , wherein each of the caster-supporting elements further comprises an axle comprising a section connected to the wall and another section connected to the corresponding one of the casters. 
     
     
         5 . The treadmill according to  claim 4 , wherein the axle comprises a non-circular enlarged end, wherein the wall comprises:
 a non-circular cavity for receiving the non-circular enlarged end of the axle to prevent rotation of the axle relative to the wall; and   a bore via which another end of the axle extends to the corresponding one of the casters.   
     
     
         6 . The treadmill according to  claim 5 , wherein the wall further comprises an annular protuberance around the cavity. 
     
     
         7 . The treadmill according to  claim 6 , wherein the wall further comprises an annular protrusion around the bore, wherein the annular protrusion keeps the wall from the corresponding one of the casters. 
     
     
         8 . The treadmill according to  claim 1 , further comprising a frame, wherein the caterpillar track extends around the frame and comprises an upper section above the frame and a lower section below the frame, wherein some of the casters are connected to the upper section of the caterpillar track, and wherein some others of the casters are connected to the lower section of the caterpillar track. 
     
     
         9 . The treadmill according to  claim 8 , wherein the frame comprises:
 two lateral beams extending between the upper and lower halves of the caterpillar track;   two upper rails respectively supported on the lateral beams; and   two upper pads respectively extending on the upper rails, wherein the upper pads are in contact with the casters connected to the upper section of the caterpillar track.   
     
     
         10 . The treadmill according to  claim 9 , wherein the upper pad is L-shaped in a cross-sectional view. 
     
     
         11 . The treadmill according to  claim 9 , wherein the upper pad is a flat one. 
     
     
         12 . The treadmill according to  claim 9 , wherein the frame comprises:
 two lower rails respectively supported on the lateral beams; and   two lower pads respectively extending on the lower rails, wherein the lower pads are in contact with the casters connected to the lower section of the caterpillar track.   
     
     
         13 . The treadmill according to  claim 12 , wherein the lower pad is a flat one. 
     
     
         14 . The treadmill according to  claim 12 , wherein the frame further comprises two limiting elements respectively supported on the lateral beams, wherein each of the limiting elements extends between a corresponding one of the upper rails and a corresponding one of the lower rails, and wherein each of the limiting elements is used to abut against an upper portion of a corresponding one of the casters connected to the lower section of the caterpillar track. 
     
     
         15 . The treadmill according to  claim 14 , wherein each of the limiting elements comprises a connective portion extending vertically, wherein the connective portion is connected to a corresponding one of the lateral beams.