US Patent 7041035 Exercise methods and apparatus with elliptical foot motion

An exercise device has left and right rails that are supported on respective pairs of equal length rocker arms, and left and right skates that are movably mounted on respective rails. Left and right cranks move the rails relative to a frame, and move the skates along the rails in a manner that defines adjacent paths of generally elliptical foot motion, while maintaining the foot supports in a fixed orientation relative to the frame.