Manually powered treadmill

Abstract

A manually powered treadmill includes a frame; front and rear running belt pulleys coupled to the frame; a first bearing rail including a first plurality of bearings and a second bearing rail including a second plurality of bearings; a running belt at least partly supported by the first and second plurality of bearings and at least one of the front or rear running belt pulleys, where at least a portion of the running belt defines a curved running surface; and a safety device to prevent rotation of one of an inner outer rings of the safety device and one of the front or rear running belt pulleys in a first rotational direction, but allow in a second rotational direction, the one of the front or rear running belt pulleys and the one of the inner or outer rings to freely rotate.

What is claimed: 
     
         1 . A manually powered treadmill comprising:
 a frame;   a front running belt pulley coupled to the frame;   a rear running belt pulley coupled to the frame and spaced apart from the front running belt pulley;   a first plurality of bearings coupled to the frame;   a second plurality of bearings coupled to the frame;   a running belt at least partly supported by the first plurality of bearings, the second plurality of bearings, and at least one of the front running belt pulley or the rear running belt pulley, wherein the running belt includes a running surface, at least a portion of which is a curved running surface; and   a safety device coupled between the frame and at least one of the front running belt pulley and the rear running belt pulley, the safety device comprising an inner ring and an outer ring, wherein one of the front running belt pulley and the rear running belt pulley and one of the inner ring and the outer ring is restricted from rotation relative to the frame in a first rotational direction, however, in a second rotational direction opposite the first rotational direction, the one of the front running belt pulley and the rear running belt pulley and the one of the inner ring and the outer ring freely rotate relative to the frame.   
     
     
         2 . The manually powered treadmill of  claim 1 ,
 wherein the frame comprises at least one cross-member, a left side member, and a right side member; and   wherein the at least one cross-member extends between the left side member and the right side member.   
     
     
         3 . The manually powered treadmill of  claim 1 , wherein at least one of the first plurality of bearings or the second plurality of bearings are supported by a bearing rail. 
     
     
         4 . The manually powered treadmill of  claim 1 , wherein at least one of the first plurality of bearings or the second plurality of bearings defines in part a curved top profile corresponding to the curved running surface. 
     
     
         5 . The manually powered treadmill of  claim 1 , wherein at least one of the first plurality of bearings or the second plurality of bearings defines a curved top profile, and wherein the running belt substantially assumes the shape of the curved top profile to form the curved running surface. 
     
     
         6 . The manually powered treadmill of  claim 1 , wherein the running belt at least partially contacts at least one of the first plurality of bearings or the second plurality of bearings. 
     
     
         7 . The manually powered treadmill of  claim 6 , wherein the running belt comprises an outer surface opposite an inner surface, and wherein the outer surface comprises the running surface and the inner surface at least partially contacts at least one bearing of the first plurality of bearings or the second plurality of bearings. 
     
     
         8 . The manually powered treadmill of  claim 1 , wherein the safety device comprises a one-way bearing including the inner ring and the outer ring. 
     
     
         9 . The manually powered treadmill of  claim 8 , wherein the one-way bearing further includes a plurality of sprags disposed between the inner ring and outer ring, wherein the plurality of sprags are shaped to prevent rotation of at least one of the inner ring or the outer ring in the first direction while permitting rotation of the at least one of the inner ring or the outer ring in the second direction. 
     
     
         10 . A manually powered treadmill comprising:
 a frame having a front end and a rear end opposite the front end;   at least one rotatable element coupled to the frame;   a plurality of bearings coupled to the frame;   a running belt at least partly supported by the plurality of bearings and the at least one rotatable element, wherein the running belt includes a running surface, at least a portion of which is curved; and   a safety device coupled between the frame and to the rotatable element, the safety device comprising an inner race and an outer race, wherein the safety device is structured to permit the rotatable element and at least one of the inner race or the outer race to freely rotate in only one rotational direction.   
     
     
         11 . The manually powered treadmill of  claim 10 , wherein one of the inner race and the outer race is substantially fixed to restrict rotation thereof relative to the other of the one of the inner race and the outer race. 
     
     
         12 . The manually powered treadmill of  claim 10 , wherein the at least one rotatable element comprises at least one running belt pulley, the at least one running belt pulley supporting at least a portion of the running belt. 
     
     
         13 . The manually powered treadmill of  claim 10 , wherein the safety device permits the running belt to freely rotate in the only one rotational direction. 
     
     
         14 . The manually powered treadmill of  claim 10 , wherein the inner race and the outer race cooperate with one another as elements of a one-way bearing. 
     
     
         15 . The manually powered treadmill of  claim 10 , wherein the plurality of bearings defines a curved top profile corresponding to the curved running surface. 
     
     
         16 . The manually powered treadmill of  claim 10 , wherein the plurality of bearings defines a curved top profile, and wherein the running belt substantially assumes the shape of the curved top profile to form the running surface. 
     
     
         17 . The manually powered treadmill of  claim 10 , wherein the running belt comprises an outer surface opposite an inner surface, and wherein the outer surface comprises the running surface and the inner surface at least partially contacts the plurality of bearings. 
     
     
         18 . A treadmill, comprising:
 a frame;   at least one running belt pulley coupled to the frame;   a plurality of bearings coupled to the frame, wherein the plurality of bearings define a curved top profile;   a running belt at least partly supported by the at least one running belt pulley and the plurality of bearings, wherein the running belt comprises a running surface, at least a portion of which comprises a curved running surface corresponding to at least a portion of the curved top profile; and   a one-way bearing coupled between the frame and the at least one running belt pulley, the one-way bearing comprising an inner ring and an outer ring, wherein the at least one running belt pulley and one of the inner ring and the outer ring are restricted from rotation relative to the frame in a first rotational direction, however, in a second rotational direction opposite the first rotational direction, the at least one running belt pulley and the one of the inner ring and the outer ring rotate freely relative to the frame.   
     
     
         19 . The treadmill of  claim 18 , wherein a plurality of elements are disposed intermediate the inner ring and the outer ring. 
     
     
         20 . The treadmill of  claim 19 , wherein the plurality of elements comprise sprag elements.