Patent ID: 7226401

Claim:
An exercise machine comprising: a frame; a piston and cylinder assembly which is supported by the frame; an apparatus for establishing a controlled fluid pressure inside the cylinder; a first actuator which is movable by a user from a first rest position against a first resistance force which is dependent at least on the fluid pressure inside the cylinder, to cause telescopic movement of the piston and cylinder assembly, the first actuator including at least a first device which is movable by the user and a first mechanical advantage system connected to the piston and cylinder assembly whereby movement of the first device by a first distance causes corresponding telescopic movement of the piston and cylinder assembly by a second distance which is smaller than the first distance; and a second actuator which is movable by the user from a second rest position against a second resistance force which is dependent at least on the fluid pressure inside the cylinder, to cause telescopic movement of the piston and cylinder assembly, the second actuator including at least a second device which is movable by the user and a second mechanical advantage system connected to the piston and cylinder assembly whereby movement of the second device by a third distance causes corresponding telescopic movement of the piston and cylinder assembly by a fourth distance which is smaller than the third distance; wherein the fluid pressure in the cylinder is increased by the telescopic movement of the piston and cylinder assembly, and exerts a force which tends to extend the assembly and restore the first actuator to the first rest position and the second actuator to the second rest position, wherein the piston includes a piston head which is mounted for reciprocating movement inside the cylinder and a piston rod which is attached to the piston head and which extends from the cylinder, the piston rod having a hollow interior, a sealed end which is remote from the cylinder and an open mouth which is located inside the cylinder whereby the fluid pressure in the hollow interior is the same as inside the cylinder, the fluid pressure inside the cylinder on opposed sides of the piston head being the same, and wherein the increase in fluid pressure in the cylinder due to the telescopic movement of the piston and cylinder assembly, is dependent on the extent to which the piston rod extends into the cylinder.