METHOD AND APPARATUS FOR DRIVING PUSHING DEVICE

摘要

PROBLEM TO BE SOLVED: To achieve efficient propulsion by reducing the consumption of energy by means of a simple arrangement of a hydraulic pressure circuit when a jacking pipe is pushed into the ground by the small actuator of a pushing device. SOLUTION: An apparatus for driving the root pushing device is used in jacking method which propels an end device into the ground via a propulsion pipe. A fluid pressure pump 52 driven by an rpm-controlling drive 51 consisting of an inverter motor 50 is provided in the hydraulic flow passage 34 of a fluid pressure circuit 36 having both the hydraulic flow passage 34 and a return flow passage 35, with the hydraulic flow passage connected to a cylinder 5 via a main selector valve 33. A hydraulic fluid pressure adjusting device 54 is provided between the passages 34 and 35. A control device 57 is provided for controlling the hydraulic fluid to a low-rate-of-flow, high-pressure condition or a high-rate-of-flow, low-pressure condition by imparting propulsion command signals 55a and 55b or no-load command signals 56a and 56b to the drive 51 and the adjusting device 54.