HYDRAULIC CIRCUIT FOR AUGER LIFTING APPARATUS OF PILE DRIVER

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic circuit for an auger lifting apparatus of a pile driver, which allows an auger rotation drive unit to accelerate a lowering speed through simple operation in accordance with acceleration of the screwing speed of a steel pile.;SOLUTION: According to the hydraulic circuit, a lowering-side switch valve 13 is arranged across a circuit connecting lowering-side channels 8a, 8b for respective two hydraulic motors 4, 4 for vertically moving the auger rotation drive unit 3 along a leader 1. Then, a circuit 9c branched from a lifting-side channel 9a for one of the hydraulic motors 4 is switchably connected to the lowering-side switch valve 13, and a lifting-side switch valve 14 is arranged across a circuit connecting lifting-side channels 9a, 9b together. Further, a circuit 8c branched from the lowering-side channel 8a for the one hydraulic motor is swichably connected to the lifting-side switch valve 14.;COPYRIGHT: (C)2002,JPO