HYDRAULIC LIFTING, DEAD WEIGHT DROP SYSTEM PILE DRIVING DEVICE

摘要

PURPOSE:To enable a hydraulic device to be miniaturized more than a hydraulic forced system and to reduce the generation of noise at an operating time, by a method wherein, after a weight is lifted by a hydraulic means, it is dropped under its own weight, and this causes striking of a pile head, which results in driving-in of the pile. CONSTITUTION:Through the drive of a hydraulic pump 27 and the operation of a 2-way switch valve 22, pressurized oil is pressed in between a piston 16 and a cylinder 7, and as a result, a weight 6 is raised with the upward movement of the cylinder 7. When the weight 6 reaches an upper limit, an oil feed and discharge pipe 18 is caused to be open to a line 24 with the 2-way switch valve 22 actuated, and as a result, the weight 6 drops with its dead weight to strike an iron bed 12 to press in a pile head 35 engaging said iron bed 12. The rise in pressure of return oil at a time when the weight 6 drops through the dead weight is relieved by means of an oil amount control tank 20. After dead weight dropping of the weight 6 is completed, the 2-way switch valve 22 is changed over, the device is further restored to an initial operation condition, and operations to drive the pile are performed in a repeated manner.