Abstract: A plastic air cylinder assembled by the specific combination of a plurality of metal tie rods, inside and outside nuts, a resilient and compressible member and supporting plates whereby the plastic cylinder tube is permitted to expand more than the metal tie rods.

Abstract: This invention relates to self-lubricating bearings or other antifriction elements formed of a lubricant-containing polyacetal. It can be manufactured in various shapes by molding a powdery mixture of the polyacetal having a bulk factor of 2-8 with 2-12 wt % of the lubricant which is in a liquid state at a normal room temperature or at the melting point of the polyacetal by a screw type injection molding machine having controlled temperatures in the feed, compression, metering and nozzle sections of the heating cylinders.During the process, the lubricant is uniformly dispersed in said resin material as fine particles independent from each other and this accounts for the extraordinarily high retention of lubricant film which forms on the bearing surface of the molded articles in use.

Abstract: This invention relates to self-lubricating bearings or other anti-friction elements formed of a lubricant-containing polyamide. It can be manufactured in various shapes by molding a powdery mixture of the polyamide having a bulk factor of 2 - 5 with 2 - 12 wt % of a lubricant which is in a liquid state at a normal room temperature, are at a temperature between the room temperature and the polyamide melting temperature by the screw type injection or extrusion molding machine having controlled temperatures of the heating cylinders in the feed, the compressions, the metering, and the nozzle sections of the extruder.