PILE PRESS-IN MACHINE, AND PRESSURE CONTROL METHOD

To provide a pile press-in machine capable of accurately detecting hydraulic pressure in a gripping mechanism and stably operating the gripping mechanism while reducing a size and weight of a device.SOLUTION: A pile press-in machine for pressing-in piles into a ground comprising a gripping mechanism having a plurality of cylinders includes: a pressure control circuit that supplies hydraulic pressure to the gripping mechanism; a pressure detection mechanism that detects hydraulic pressure in the pressure control circuit; and a plurality of branch circuits that branch from the pressure control circuit and supply hydraulic pressure to the plurality of cylinders. Some of the plurality of branch circuits maintain pressure. Remaining branch circuits use the gripping mechanism as a pressure accumulation mechanism that accumulates pressure accompanied by supply of hydraulic pressure to the cylinder by elastic deformation of the gripping mechanism, and circulate a part of the hydraulic pressure supplied to the cylinder to the pressure control circuit.SELECTED DRAWING: Figure 4 【課題】装置の小型化や軽量化と併せて、精度良く把持機構における油圧の圧力検知を行い、把持機構を安定的に作動させることが可能な杭圧入機を提供する。【解決手段】杭を地盤に圧入する杭圧入機であって、複数のシリンダを有する把持機構を備え、前記把持機構に油圧を供給する圧力制御回路と、前記圧力制御回路内の油圧の圧力を検知する圧力検知機構と、前記圧力制御回路から分岐して前記複数のシリンダに油圧を供給する複数の分岐回路と、を有し、前記複数の分岐回路の一部では圧力保持を行い、残りの分岐回路では前記把持機構を前記シリンダへの油圧の供給に伴う圧力を当該把持機構の弾性変形によって蓄圧する蓄圧機構として用い、前記シリンダへ供給された油圧の一部を前記圧力制御回路に還流させるように構成される。【選択図】図４