Resistance device

Abstract

A resistance device includes an impeller rotatably mounted on an impeller shaft and housed in an impeller housing, the impeller configured to act on an working fluid, a one-way drive assembly connected to the impeller shaft and configured to drive the impeller in one direction, the one-way drive assembly including a driving shaft connected thereto, a variable moment arm drive operatively connected to the driving shaft and configured to modify a distance between the driving shaft and a cable force vector applied to the variable moment arm drive, the variable moment arm drive including a cable connection portion, and a cable connected to the cable connection portion of the variable moment arm drive via a return spring, the cable configured to be pulled by a user.

What is claimed is: 
     
         1 . A resistance device, comprising:
 an impeller rotatably mounted on an impeller shaft and housed in an impeller housing, the impeller configured to act on an working fluid;   a one-way drive assembly connected to the impeller shaft and configured to drive the impeller in one direction, the one-way drive assembly including a driving shaft connected thereto;   a variable moment arm drive operatively connected to the driving shaft and configured to modify a distance between the driving shaft and a cable force vector applied to the variable moment arm drive, the variable moment arm drive including a cable connection portion; and   a cable connected to the cable connection portion of the variable moment arm drive via a return spring, the cable configured to be pulled by a user.   
     
     
         2 . The resistance device of  claim 1 , wherein the one-way drive assembly includes a ratchet and pawl. 
     
     
         3 . The resistance device of  claim 1 , wherein the impeller includes a plurality of variable pitch blades. 
     
     
         4 . The resistance device of  claim 3 , wherein the resistance device includes an impeller blade pitch control. 
     
     
         5 . The resistance device of  claim 4 , wherein the pitch control includes a setting for at least a maximum resistance and a minimum resistance. 
     
     
         6 . The resistance device of  claim 1 , further comprising a stator mounted inside the impeller housing adjacent to the impeller and configured to remove momentum from the working fluid. 
     
     
         7 . The resistance device of  claim 1 , wherein the variable moment arm drive includes a cable wrapping surface having a cycloidial shape such that the moment arm changes as a function of a length of a cable pull to require a constant force input by a user. 
     
     
         8 . The resistance device of  claim 1 , wherein the variable moment arm drive includes a mechanical moment arm operatively connected to a controller, wherein the controller is configured to determine the distance between the driving shaft and the cable force vector and to set the mechanical moment arm to the determined distance to require a constant force input by a user. 
     
     
         9 . A resistance device, comprising:
 an impeller rotatably mounted on an impeller shaft and housed in an impeller housing, the impeller configured to act on an working fluid, wherein the impeller includes a plurality of variable pitch blades to modify a resistance;   a one-way drive assembly connected to the impeller shaft and configured to drive the impeller in one direction, the one-way drive assembly including a driving shaft connected thereto; and   a cable connected to the driving shaft, the cable configured to be pulled by a user.   
     
     
         10 . The exercise machine of  claim 9 , wherein the one-way drive assembly includes a ratchet and pawl. 
     
     
         11 . The exercise machine of  claim 9 , further including a variable moment arm drive operatively connected to the driving shaft and configured to modify a distance between the driving shaft and a cable force vector applied to the variable moment arm drive, the variable moment arm drive including a cable connection portion. 
     
     
         12 . The resistance device of  claim 9 , further including a pitch control including a setting for at least a maximum resistance and a minimum resistance. 
     
     
         13 . The resistance device of  claim 9 , further comprising a stator mounted inside the impeller housing adjacent to the impeller and configured to remove momentum from the working fluid. 
     
     
         14 . The resistance device of  claim 11 , wherein the variable moment arm drive includes a cable wrapping surface having a cycloidial shape such that the moment arm changes as a function of a length of a cable pull to require a constant force input by a user. 
     
     
         15 . The resistance device of  claim 11 , wherein the variable moment arm drive includes a mechanical moment arm operatively connected to a controller, wherein the controller is configured to determine the distance between the driving shaft and the cable force vector and to set the mechanical moment arm to the determined distance to require a constant force input by a user. 
     
     
         16 . The resistance device of  claim 9 , further including an automatic pitch control configured to determine a suitable pitch of the variable pitch blades to require a user to apply a constant force over a range of motion, the automatic pitch control configured to modify the pitch to the suitable pitch. 
     
     
         17 . A exercise machine, comprising:
 an impeller system connected to a drive shaft;   a pull cable connected to the drive shaft; and   a constant force system operatively connected to the cable and the impeller system such that the pull cable can be pulled at a constant force while maintaining a constant pull rate.   
     
     
         18 . The exercise machine of  claim 17 , wherein the impeller system includes an impeller and a stator, the impeller configured to impart momentum on working fluid and the stator configured to absorb momentum from the working fluid. 
     
     
         19 . The exercise machine of  claim 17 , wherein the constant force system includes a variable moment arm drive that varies the moment arm as a function of cable pull to account for impeller or working fluid momentum. 
     
     
         20 . The exercise machine of  claim 17 , wherein the constant force system includes a plurality of variable pitch blades connected to the impeller to modify dynamically generated forces on the impeller to account for impeller or working fluid momentum.