Submarine retractable unit and method for its manufacture

摘要

A piston rod of the cylinder is made of a composite plastic material and comprises an outer tube(9) of plastic, with low friction properties and a filling(12) of plastic material which increases mechanical strength and stiffness of the piston rod. The tube is at least partly filled by the plastic material which extends along the inside of the tube. The filling(12) comprises a binder material and bundles of plastic reinforcing fibers(13), the binder forming an adhesive bond to the outer tube(9). An additional plastic inner tube with low friction properties may run parallel to the outer tube and hold a further piston rod. Space between the tubes is filled with the said plastic filling. At least one tube has a non-circular cross-section, preferably a regular polygon. In a fluid operated cylinder unit fluid powered cylinder has a cylinder body with a composite structure comprising an internal tube of low friction material and an external part of plastic fibers in a binder. In the latter design one end of the cylinder body is closed with a plastic foot and the other end with a plastic head. Independent claims are included for the following: (a) a process for manufacturing a piston rod for the cylinder unit in which an outer tube(9), or the space between an additional inner tube and the outer tube, is filled with plastic reinforcing fibers(13) and both ends of the outer tube or both tubes are provided with end caps(10,11), one of which has an opening through which a curable binder(14) for the fibers is introduced into the prefilled tube while vacuum is applied via an outlet in the other end cap; and (b) a process for manufacturing a cylinder for the cylinder unit in which an internal tubular section of the cylinder body is produced in a thermoplastic or thermosetting plastic material with low friction properties, closed at the ends by a foot and head parts and the tube, foot and head parts are wrapped in reinforcing plastic fibers which are impregnated with a curable adhesive or resin either before, during or after winding.