VERTICAL MOTION SWITCHING MECHANISM FOR PILE GRIPPING DEVICE IN PILE PRESS-IN/PULLING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a vertical motion switching mechanism for a pile gripping device capable of omitting a time lag occurring during the vertical motion of a pile press-in/pulling cylinder due to turning on/off a vertical motion selector valve for preventing increase in jacking resistance due to adhesion of earth to a pile and improving efficiency of pile press-in/pulling work.;SOLUTION: In this vertical motion switching mechanism provided with a base 2 having a reaction force gripping device 3 and fixed on an existing pile, a slide base 4, a guide frame 6, the pile press-in/pulling cylinder 9, an elevation body 8, and the pile gripping device 10, a rotary switching mechanism for switching the vertical motion selector valve is arranged in addition to the vertical motion selector valve supplying pressure oil to the pile press-in/pulling cylinder 9. The rotary switching mechanism is constructed of a rotary selector valve 19, a hydraulic motor 18 directly connected to a rotor 24 in the rotary selector valve 19, a rotary valve driving flow rate regulating valve 21 regulating a speed of the vertical motion of the pile press-in/pulling cylinder by the rotational speed of the hydraulic motor, a press-in/pulling oil pressure regulating valve 23, and a shut off valve 22.;COPYRIGHT: (C)2003,JPO