Stepmill

Abstract

A stair climbing machine includes a plurality of steps connected, via a drive assembly, to, the frame of the machine to move in a closed loop path which brings each step to a position near the ground to provide a low step-on height. The drive assembly may optionally be supported on a movable portion of the frame to allow the incline of the closed loop path to be selectively varied to adjust the vertical distance between adjacent steps of the machine.

What is claimed is: 
     
         1 . A stair climbing machine comprising:
 a frame including a base and an upright frame movably coupled to the base;   a plurality of steps movably coupled to the upright frame to move in a closed loop path;   a lift mechanism operatively coupled to the upright frame to selectively change a position of the upright frame relative to the base to change a step-height of the plurality of steps.   
     
     
         2 . The stair climbing machine of  claim 1 , wherein the upright frame comprises a left frame portion and a right frame portion and where the steps are positioned between the left and right frame portions, wherein each of the left and right frame portions define a respective four-bar linkage. 
     
     
         3 . The stair climbing machine of  claim 2 , wherein the four-bar linkage comprises first, second, and third links movably coupled to the base and a fourth link that remains fixed to the base during changes in the position of the upright frame. 
     
     
         4 . The stair climbing machine of  claim 2 , wherein each step has a heel end and a toe end, and wherein the plurality of steps are coupled to the upright frame via a drive assembly configured to constrain the movement of the toe ends of the steps along a first closed loop path and the movement of the heel ends of the steps along e second closed loop path having a different shape than a shape of the first closed loop path. 
     
     
         5 . The stair climbing machine of  claim 4 , wherein the toe ends of the steps a coupled to one or more first flexible members routed in a first continuous loop around a set of first guide disks, and where the heel ends of the steps are coupled to one or more second flexible members routed in a second continuous loop around a set of second guide disks. 
     
     
         6 . The stair climbing machine of  claim 5 , wherein each of the steps is configured to bend around one or more of the first and second guide disks. 
     
     
         7 . The stair climbing machine of  claim 6 , wherein each step comprises plurality of slats operatively coupled together to support a user's foot when provided in a flat configuration, wherein adjacent slats are configured to pivot relative to one another about an axis parallel with a length of the slats to allow the step to bend around the one or more of the first and second guide disks. 
     
     
         8 . The stair climbing machine of  claim 1 , wherein the upright frame is selectively adjustable to any of a plurality of inclined angles including art incline angle of about 55 degrees. 
     
     
         9 . The stair climbing machine of  claim 1 , wherein the upright frame is selectively adjustable to an inclined angle of about zero degrees reducing the step-height to about zero. 
     
     
         10 . The stair climbing machine of  claim 2 , wherein the respective four-bar linkages defined by the left and right frame portions are primary four-bar linkages, the stair climbing machine further comprising a handlebar assembly that defines left and right secondary four-bar linkages associated with a respective one of the left and right frame portions, wherein each of the secondary four-bar linkages is operatively coupled to the respective primary four-bar linkage whereby each of the secondary four-bar linkages moves as a result of the movement of the respective primary four-bar linkage. 
     
     
         11 . The stair climbing machine of  claim 1 , wherein each of the plurality of steps comprises a monolithic support platform having a user-supporting side and an underside located opposite the user-supporting side, wherein the closed loop path of the steps has a front side and a rear side, and wherein the steps are oriented such that the user-supporting side of the steps is generally oriented towards a user, when using the stair climbing machine, when the steps are traversing the rear side of the closed loop path. 
     
     
         12 . The stair climbing machine of  claim 1 , further comprising a step flipper located near an upper side of the closed loop path, the step flipper pivoting each step approaching the upper side of the closed loop path in a direction opposite a direction of travel of the steps along the closed loop path. 
     
     
         13 . The stair climbing machine of  claim 1 , wherein each step has a heel end and a toe end that move along respective heel end and toe end paths to define respective closed loop paths of the steps, and wherein one of the heel ends or toe ends of the steps is constrained along its respective closed loop path by a flexible member while the other one of the heel ends or toe ends of the steps is constrained along its respective closed loop path by a track system, wherein the heel end of each step moves along a path defined by the track system, and wherein each step is further intermittently supported at a location between the toe end and the heel end of the step. 
     
     
         14 . The stair climbing machine  claim 1 , further comprising a resistance mechanism configured to adjustably resist the movement of the steps along the closed loop path. 
     
     
         15 . A stair climbing machine comprising:
 a frame comprising a base and an upright frame;   a plurality of steps movably coupled to the upright frame to move in a closed loop path, wherein the plurality of steps are spaced apart from one another such that individual steps do not contact one another as the steps move in the closed loop path, and wherein each of the plurality of steps comprises a supporting platform provided by a plurality of individual slats pivotally connected to one another to allow the step to transition, while moving along the closed loop path, between a flat configuration in which user-supporting surfaces of the slats are substantially co-planar and a bent configuration in which the user-supporting surfaces of at least two adjacent the slats are pivoted away from one another.   
     
     
         16 . A stair climbing machine comprising:
 a base;   first and second upright frames coupled to opposite sides of the base;   a plurality of steps positioned in a space defined between the first and second upright frames and movably coupled to the first and second upright frames to move in a closed loop within the space, wherein each step has a toe end constrained to move along a first closed loop path and a heel end constrained to move along a second closed loop path different from the first closed loop path and which crosses the first closed loop path, wherein the first closed loop path is defined by at least one flexible member routed around and engaged with a corresponding plurality of rotating disks, and wherein the second closed loop path is defined by a track system.   
     
     
         17 . The stair climbing machine of  claim 16 , wherein each step has a first and second lateral side extending between the toe end and the heel end of each step, wherein each step comprises a first support extending from each of the first and second lateral sides that couples the toe end of the step to a respective flexible member, and a second support extending from each of the first and second lateral sides that operatively engages the heel end of the step to a respective side of the track system, wherein the step further comprises a third support extending from each of the first and second lateral sides that intermittently engages at least one track member of the respective side of the track system. 
     
     
         18 . The stair climbing machine of  claim 17 , wherein a secondary track is positioned to temporarily engage the third support of each step to support the step while the heel end of the step traverses a discontinuity in a track. 
     
     
         19 . The stair climbing machine of  claim 16 , wherein the first and second upright frames are movably coupled to the base for selectively changing the closed loop traversed by the steps, wherein each of the first and second upright frames define a four-bar linkage, and wherein a fixed link of the four-bar linkage is arranged parallel to the base. 
     
     
         20 . The stair climbing machine of  claim 19 , further comprising a handlebar assembly that defines a secondary four-bar linkage, and wherein a fixed link of the secondary four-bar linkage is defined by an upright support of the handlebar assembly.