Patent ID: 8277366

Claim:
A stair-stepping exercise machine for developing certain muscle groups by emulating a stair climbing motion comprises: a base frame; a median member located on a upper front edge of said base frame and extending therealong, further comprising a half-cylinder shape enclosure housing an internal pivoting assembly; a pair of independently movable and parallel stepping pedals, each comprising a first end operably connected to said pivoting assembly and rearwardly extending from said median member and terminating at a second end; a pair of pneumatic shock absorbers, one for each of said pair of independent movable stepping pedals, each shock absorber mounted to said base frame and said second end of each of said pair of stepping pedals; a vertical support arm axially attached to said median member and comprising a first lower support member, a second lower support member, and an upper support member; and, a handlebar assembly pivotally attached to said upper support member; wherein said first and second lower support members are rotatingly attached to said pivoting assembly; wherein said upper support member is rotatingly attached to said first and second lower support members; wherein said handlebar assembly is rotatingly attached to said upper support member; wherein a user initiates an alternating stepping pattern by applying a stepping force as one stepping pedal is in a lower position and an opposing stepping pedal is in an upper position; wherein upon applying said stepping force to each stepping pedal, a said pair of pneumatic shock absorbers apply a counteractive resistive force; wherein said exercise machine is collapsible between a deployed configuration and a compact collapsed configuration; wherein said vertical support arm may be stably grasped by a user of said exercise machine; and, wherein said base frame comprises a light-weight five-sided box structure having an open top portion for optimum stability and strength and further comprises a floor portion having a pair of recessed shock absorber cavities along a rear portion, each receiving one of said pair of shock absorbers.