US Patent 7097593 Combination of treadmill and stair climbing machine

A combination of treadmill and stair climbing machine includes a single roller supported on a shaft between two lugs on two sides of the frame of the combination and two rear ends of two pedals are respectively connected to the roller and supported on the two lugs. Two front ends of the two pedals are respectively connected to two hydraulic cylinders. A switch member is pivotably connected to a front end of the frame and can be set in a horizontal position when the combination is used as stair climbing machine, and an inclined position when the combination is used as treadmill. An L-shaped plate is connected to the frame and each pedal has a connection plate which has two elongate holes in which two protrusions on each side of the L-shaped plate are movably engaged, such that the pedals are pivotably supported on the L-shaped plate when used as stair climbing machine.