Patent ID: 6129003
Filing Date: 2000-10-10
Classification: F15B

Abstract:
A fluid pressure cylinder apparatus comprising:a cylinder body having a cylinder hole inside;an outer piston slidably accommodated in said cylinder hole;a hollow outer rod connected to the outer piston such that a tip of the outer rod extends from said cylinder body to an exterior;an inner piston slidably accommodated inside the outer rod and fixed to said cylinder body using an inner rod that penetrates said outer piston;a tube head mounted at the tip of said outer rod opposite said inner piston;a first pressure chamber on one side of said outer piston;a second pressure chamber between said inner piston and said tube head;a third pressure chamber between said outer piston and said inner piston;a first port leading to said first and second pressure chambers;a second port leading to said third pressure chamber;a rotation-preventing mechanism for preventing free rotation of said outer piston;wherein said rotation-preventing mechanism is composed of at least one engaged groove formed in an inner surface of said cylinder body integrally with the cylinder hole and at least one engaging member mounted on an outer circumference of said outer piston and fitted in said engaged groove so as to move along the engaged groove;wherein said engaging member includes a key that is fitted in the engaged groove and bushes mounted on respective sides of the key, said bushes slidably contacting respective side walls of said engaged groove to facilitate sliding of the key.