Single-acting pressure operated servo motor - has elliptical cylinder and piston enclosing springs with opposed helices

摘要

The cylinder (12) and the piston can have an oval or elliptical cross section. The working chamber between the piston and the cylinder walls has two restoring springs (44, 46) which are arranged symmetrically relative to the working chamber longitudinal axis. The springs have opposite helices. the cylinder and the piston can be made from plastics by injection moulding.