Patent ID: 7451688
Filing Date: 2008-11-18
Classification: F15B

Abstract:
1. A lock mechanism for restricting displacement of a piston, usable in a fluid pressure-operated apparatus comprising: a cylinder body to which a pressure fluid is supplied via a supply port, and wherein said piston is displaceable in an axial direction in said cylinder body under a pressing action effected by said pressure fluid, said lock mechanism comprising: a fastening section provided integrally with said piston, which protrudes on one end side of said cylinder body in a displacement direction of said piston, and which includes an annular groove disposed along an outer circumferential surface thereof; a retaining section disposed in said cylinder body, into which said fastening section is inserted, and which comprises a retaining member that is displaceable in a direction substantially perpendicular to an axis of said fastening section; and an urging section disposed in an installation hole at one end of said cylinder body for urging said retaining member toward said fastening section, said urging section comprising an elastic member made of an elastic material that exerts a resilient force in said axial direction of said cylinder body, and a converting member, which is displaceable in said axial direction by said resilient force of said elastic member, and which converts an urging direction of said resilient force into a direction that is substantially perpendicular to said axis, so that said force is transmitted to said retaining member, said elastic member being disposed between an outer circumferential surface of said converting member and an inner circumferential surface of said installation hole, wherein said retaining member is displaced toward said fastening section under an urging action effected by said urging section, and said retaining member engages with said annular groove when said fastening section is inserted into said retaining section and said annular groove is opposed to said retaining member.