Thin cylinder with load possible of dense forest preventing

摘要

A thin cylinder enabling slip prevention of an operation rod of the present invention comprises: a cylinder main body including a first flow path which has an operating rod inserted into a front side of the cylinder main body such that the operating rod is movable forward and backward, and which has a first hydraulic pressure flown into a rear side thereof to move the operating rod forward, and including a second flow path into which a second hydraulic pressure is flown to move the operating rod backward; a first check valve which is installed in the first flow path; a second check valve which is installed in the second flow path; and a valve control unit including an initial operating unit which opens the first check valve to move the operating rod forward by the first hydraulic pressure, a position sensor which is operated only in a state that the first check valve is opened to sense the movement of the operating rod, and a slip preventing operation unit which closes the first check valve when the position sensor senses that the operating rod is moved as much as a preset forward movement distance, thereby blocking a backward movement due to slip of the operating rod.