Abstract: An actuator which comprises a pair of elongated elastomer tubes (6,16), sealed by respective members (18, 20, 22, 24) at each end, the members at the one end (18, 20) being fixed and the members at the opposite end (22, 24) sliding in guides (34, 36), the sliding ends of the first and second tubes being connected by a chain (26) and sprocket (10) to convert linear motion to rotary motion.

Abstract: The device comprises an elongated elastomer tube, sealed tightly by clamps at each end against disk shaped end pieces, the one end disk fixed and the other sliding, axially to the other disk, on restraining rods. An orifice in the fixed disk permits the injection of pneumatic pressure causing the expansion of the elastomer tube. Surrounding the elastomer tube is a restraining tube of woven fabric or other material which will not expand radially. The second tube is also affixed to each end disk by the clamps and has sufficient length to reach between the two disks when the disks are at their farthest distance from each other. When the disks are not fully distanced from each other, the outer tube crumples axially but not radially. Action commences when the disks are closest to each other. Controlled pneumatic pressure injected through the orifice causes expansion of the elastomer tube.