Abstract: A cylinder includes a cylinder body assembly, a cylinder rod assembly, and a piston assembly. The cylinder body assembly includes a cylinder body. The cylinder body defines a receiving chamber. The cylinder rod assembly includes a rod fixed with the cylinder body. The rod includes an inclined resisting surface. The piston assembly includes a piston, a piston rod, and one or more resisting member. The piston is slidably received in the receiving chamber and sleeved on the rod. The piston rod protrudes from the piston and extending out from the receiving chamber. The piston rod is sleeved on the rod, and defines a through hole. The resisting member is movably mounted in the through hole. The piston and the piston rod slide relative to the rod, which enable the resisting surface to resist the resisting member to be partially exposed from the through hole.

Abstract: An expander that converts the thermal energy and the pressure energy of a working medium into mechanical energy includes, within a casing (12, 15, 18), an operating part such as a group of axial piston cylinders operated by the working medium introduced into an operating chamber, and a hermetically sealed lubrication chamber (102) in which oil for lubricating at least the operating part resides. Breather chambers (101, 103) are provided in an upper part of the lubrication chamber (102), and a working medium discharge chamber (90) into which the working medium is discharged from the operating chamber is made to communicate with the breather chambers (101, 103) via breather passages (B1 to B4).

Abstract: The present invention is directed to a wobble piston and seal assembly for an oil free compressor. An upwardly directed curvature is provided on a piston surface which supports the seal. The curvature is located adjacent the perimeter of the surface to impart a slight dish shape to the surface. Preferably, the curvature has the same radius as the bend radius of the seal when the piston head is inserted into a cylinder. When the seal is initially clamped to the support surface, the seal is formed to take on the curvature of the support surface. Consequently, the seal is preformed into a shallow cup shape prior to final forming when the piston and seal assembly are inserted into a cylinder.