Composite piston with protection of the fastening screws against corrosion by a coolant

Abstract

A threaded cap screwed into the piston head with a sealed joint to a sleeve tube open and flanged at the other end are provided to encase the clamping screws that fasten the piston head and the upper piston body member and lower piston body member together. The casing thus formed shields the screws from possibly corrosive coolant that under operating conditions could work through the joints between the parts of a composite piston in spite of the clamping pressure of the screws. Each screw is screwed into the threaded cap at the piston head end and its head or a nut bears on the flange of the sleeve tube at the other end. The screws and their protective casings fit within bores in an annular strut forming a large part of the upper piston body member that butts against a low annular ridge on the underside of the piston head into which the end caps of the screw casings are screwed. A seal compressed between the annular ridge of the piston head and the annular strut of the piston body encircles each screw casing and a clearance space extending between this seal and the seal between the threaded cap and the sleeve tube is arranged to drain off any coolant that leaks into the first seal, so that it will not apply pressure to the second seal.

Dependencies are inferred from the claim text.