Patent ID: 6860189

Claim:
An actuator constructed of: (a) a first flexible hollow cylindrical fluid impermeable tube ( 6 ) which can be expanded at one free end along a central axis of the cylinder when a fluid is introduced into the tube; and contracted along the same axis when fluid is withdrawn from the tube; and (b) a second flexible hollow cylindrical fluid impermeable tube ( 16 ) which can be expanded at one free end along a central axis of the cylinder when a fluid is introduced into the tube; and contracted along the same axis when fluid is withdrawn from the tube; characterized by: (c) a first movable cable and pully mechanism with the cable affixed to the pully associated with the first and second tubes ( 6 , 16 ), and located on a first side of the first and second tubes, the first tube pulling on one end of the cable when the first tube expands upon the introduction of fluid into the first tube and the second tube contracting upon the withdrawal of fluid from the second tube; (d) a second movable cable and pulley mechanism with the cable affixed to the pulley connected by a shaft ( 11 ) to the first moveable cable and pulley mechanism and associated with the first and second tubes, and located on a second side of the first and second tubes, the first tube pulling on one and of the cable when the first tube expands upon the introduction of fluid into the first tube and the second tube contracting upon the withdrawal of fluid from the second tube; and (e) a rigid frame ( 2 ) housing the first and second flexible hollow cylindrical fluid impermeable tubes, and the first and second moveable cable and pulley mechanisms.