OIL-PRESSURE DROP HAMMER FOR DRIVING PILE

摘要

PURPOSE:To prevent the occurrence of vibration in the ground by arbitrarily setting up the driving interval of piles by a method in which the lower part of an anvil is fitted into the medium-confined chamber of an oil-pressure drop hammer for driving pile and the supply of oil to the oil-pressure cylinder of a pulley device for vertically moving ram is controlled by a differential circuit. CONSTITUTION:The lower part of an anvil 5 is inserted into the medium-confined chamber 4 of an oil-pressure drop hammer for driving pile to form a driver 3. A hammer ram 7 is housed in a cylinder 1 provided at the upside of the driver 3, and a ram 7 is vertically moved by an elevator mechanism 10 consisting of a wire rope 11 and pulley devices 12a-12c. A differential circuit 14 with a control valve is connected to the oil-pressure cylinder 13 to operate the elevator mechanism 10, and the oil in one chamber, which is to be discharged during the forward and backward strokes of the piston of the cylinder 13, is supplied to the other chamber. By such a mechanism, the action of the piston is doubled, the ram 7 is raised, and then oil pressure is shut out and the ram 7 is dropped by gravity. Thus, the vibration of the ground is prevented and the amount of man- hour is reduced.