US Patent 7121831 Balance practicing machine

A balance practicing machine that offers simplified control, reduced cost, and a compact drive assembly that reduces the space requirement for the machine. The machine includes an output shaft from one side of a power source to impart three movements to the seat in the form of a repetitive linear motion in the longitudinal direction, a repetitive pivoting motion around a longitudinal shaft, and a repetitive pivoting motion around transverse shafts. A seat base is connected to an active frame, through connector links, so as to provide swinging movement of the seat base around transverse shafts. The active frame is connected to a base member so as to allow the repetitive pivoting movement of the active frame around a longitudinal shaft.