Piston-cylinder arrangement of polygonal cross section

摘要

A piston-cylinder arrangement, particularly useful for the press shoe of an extended nip press. The cylinder is a fluid pressure cylinder with a piston, which is fluid pressure reciprocated, disposed in the cylinder chamber. The cylinder and piston are polygonal around their peripheries. A circumferential groove in the cylinder wall carries a plurality of sealing pieces which are urged outwardly of the groove and against the periphery of the piston. The sealing pieces comprise corner pieces disposed at the corners of the polygonal cylinder and second sealing pieces joining the corner pieces. Where the corner and second sealing pieces meet around the periphery of the cylinder, they have overlying, overlapping surfaces that are oriented perpendicular to the reciprocation of the piston. A spring in the groove may urge some of the pieces outwardly toward the piston. Particular beveling or rounding of the slide surfaces of the sealing pieces and a particular thickness of the sealing pieces with respect to the groove are described.