Rotational ram cylinder

Abstract From the Canadian patent

A ram cylinder assembly comprises a cylinder defining at least one closed operating chamber and having an inner surface of polygonal cross-section. A piston having an outer surface of corresponding polygonal cross-section is mounted in the cylinder for axial movement therein in response to fluid pressure in the chamber. These polygonal surfaces form a first, sliding connection. A shaft is rotatably mounted in the cylinder to extend axially through the piston while having at least one end extending to the exterior of the cylinder. An inner surface of the piston and an outer surface of the shaft have crosssections forming a second, non-circular connection. At least one of the inner surfaces …