| 摘要 |
PURPOSE:To bring a weight into a rapid free drop, by a method wherein a plug, whose breathing port is connected to the air and which breathes by a liquid amount coming in and out of a tank, is installed to the inside of a subtank, and an upper chamber of a cylinder is connected to said tank. CONSTITUTION:After a weight 15 is raised to a set position, if liquid in a lower chamber 5 of a cylinder 2 is drained through a port 7, liquid paths 18 and 19 are connected together, liquid in the lower chamber 5 of the cylinder 2 flows to an upper chamber, and a weight 15 is brought into a free drop to transfer a strike force to a cap 16 through a pile. During said motion, liquid flowing to the lower chamber 5 and the upper chamber 6 of the cylinder 2 is short by a volume of a piston rod 13, and the shortage is convered with liquid supplied to the upper chamber from a subtank 52. A plug 53 in the tank 52 breathes air from the air to expand, and as a result, liquid in the tank 52 smoothly flows to the upper chamber 52 to bring a weight 15 into a rapid free drop. |
