MACHINE FOR REMOVAL OF SOIL FROM UNDER AND GAS TRUNK PIPE LINE Russian patent published in 2000 - IPC

FIELD: construction engineering; repair of underground pipe lines. SUBSTANCE: machine includes dolly with working member (rotors) and drive for its motion in form of two hydraulic cylinders connected with extensible grips for pipe line. Dolly rests against pipe line and grips are secured on extensible telescopic beams mounted in guides of dolly. Machine operates as follows. After placing the machine on pipe line (with rotors separated beforehand) and bringing the rotors to initial working position (in the vicinity of each other), drive of rear grip is switched on and shoes clamp pipe line. The drive rotating the rotors is switched on and working pressure is delivered to piston (working) chamber of rear hydraulic cylinder. As a result, dolly moves loosening the ground under pipe line. Simultaneously, liquid from rod chamber of rear hydraulic cylinder is forced to rod chamber of front hydraulic cylinder and front grip moves to extreme front position. After completion of working stroke, control unit performs of front grip and release of rear grip. Pressure is delivered to working (piston) chamber of front hydraulic cylinder ensuring motion of dolly with rotors forward for next working stroke. Liquid from rod chamber of front hydraulic cylinder is forced to rod chamber of rear hydraulic cylinder, thus moving the rear grip to initial position. EFFECT: improved operational characteristics due to reduction of mass of machine; enhanced reliability and passability over curvilinear sections of pipe line. 2 cl, 4 dwg