JPH03134305A - Advancing and retreating device of piston pin - Google Patents

Abstract

PURPOSE:To surely perform engagement/disengagement due to a piston pin by varying aperture between an outer circumferencial part of the piston pin and an inner circumferencial surface of a cylinder, advancing and retreating the piston pin in respect to the cylinder with the force of pressure oil. CONSTITUTION:A smallest diameter part is formed on an inner circumference of a cylinder 2, while a seal 8 is arranged. Sealing is performed in respect to the smallest diameter part of a piston pin 1. A diameter of an intermediate part of the piston pin 1 is a little larger than that of the smallest part, and the largest diameter part having a little larger diameter than that of the intermediate part is steppedly formed. The inner circumference of the cylinder 2 has a shape suited to the outer circumference of the piston pin 1, however, on a nonconformity part of the diameters, oil reservoirs 7, 7' are formed. A piston returning spring 6 is arranged between the piston pin 1 and a cover 11. The projecting piston pin 1 is retreated by supplying pressure oil to hydraulic oil inlet/outlet ports 4, 4', 5, 5', while engagement/disengagement due to the piston pin 1 is surely performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston pin ejection and retraction device, and more particularly to a piston pin engagement and disengagement device of a rotation stopper device for a swing-type opening/closing bucket device.

Claims (1)

[Scope of Claims] 1) Consisting of a cylinder, a piston pin, and a spring interposed between the piston pin and the cylinder, a hydraulic oil inlet/outlet is provided in the cylinder, and a portion of the outer circumferential surface of the cylinder and an inner circumference of the cylinder are provided. A piston retraction device in which a piston pin in the cylinder can move forward and backward with respect to the cylinder by the force of pressure oil flowing in from a hydraulic oil inlet and outlet by changing the diameter in stages between the surface part and the surface part. 2) A piston pin is inserted into a cylinder with one end open and the other end closed so as to be able to move forward and backward, and the piston is normally closed by a compression spring interposed between the closed end of the cylinder and the inner end of the piston pin. By protruding the tip of the pin and providing a plurality of hydraulic oil inlets and outlets at appropriate positions in the cylinder, when pressurized oil is supplied to the hydraulic oil inlets and outlets, hydraulic pressure is applied to the hydraulic receiver provided on the piston pin and the spring is activated. 3) The piston pin retracting device of the piston pin retracting device according to claim 1, wherein the piston pin is sunk into the cylinder to open a flow path for pressure oil. A locking/disengaging device for a piston pin of a rotation stop device of a swing-type opening/closing bucket device according to claim 1, wherein the tip is configured to be lockable to/from a locking portion of a rotating body of a main bucket.