Abstract: A hydraulic motor is mounted on top of a hydraulic cylinder barrel. The barrel houses a drive shaft that is rotated by the motor. A male hex drive shaft, attached to the drive shaft, extends downward through the barrel. A piston is mounted within the barrel and moves linearly along the male hex drive shaft. Attached to the piston is a piston rod having an upper portion, a center portion, and a lower portion. The center portion defines a rod chamber for accommodating the male hex drive shaft as the piston and the piston rod move upward. The upper portion has a hexagonal inner surface for rotation and sliding movement along the male hex drive shaft. A passage through the center portion allows fluid to flow between the rod chamber and the upper chamber of the cylinder barrel.

Abstract: Multi-purpose body exercising apparatus is disclosed of the type which includes a convertible exercise bench which easily and readily converts to perform a number of different exercises thereon by means of simplified accessory attachment means fixed to the exercise bench frame which facilitates fast interchange of a variety of accessory exercise apparatus in a manner suitable and economically affordable for home use.