| 摘要 |
PURPOSE:To increase impaction on an anvil by applying downward accelerating forces to a ram by providing an air chamber in which air is compressed when pulling up the ram in between an oil-pressure cylinder device to pull up the ram and the ram. CONSTITUTION:A ram 2 is pulled up by a given stroke by an oil-pressure cylinder device 4 and then dropped to a strike an anvil 3, whereby a pile in contact with the lower side of the anvil 3 is struck. Since an air chamber 10 is provided between the ram 1 and the oil-pressure cylinder device 4, the air of the air chamber 10 is compressed wien pulling up the ram 1, and when the ram 2 drops, accelerating actions by gravity of the ram 2 and by the pressure of air are applied and the speed of the ram 2 when collision against the anvil 3 becomes faster than in the case of free dropping. When the air chamber 10 becomes negative pressures, air is sucked up from a check valve type supply valve 14. |
