| 摘要 |
PURPOSE:To perform a reliable sealing, by a method wherein a small-sized part of an anvil is fitted in a medium sealing chamber transferring a blow power to a pile head, and a seal is attached between a large-sized part of an anvil and a device body to provide a pressure reducing system. CONSTITUTION:If an anvil head 11 is hit by pressure through falling of a hammer ram 26 lifted by a ram elevating mechanism 25n, its blow power compresses a pressure accumulating medium Y, such as silicone oil, in a medium sealing chamber 6 through an anvil 8. A pile chucked by a pile head retainer member 4 is driven by the pressure force, and thereby an excessive blow power is prevented from being momentarily exerted on the pile head. The anvil consists of a small-sized fitting part 8a and a large-sized fitting part 8b, a liquid tight seal is attached between the large-sized fitting part 8b and a driven body 7a, and a pressure, being exerted on the seal, decreases due to a difference in a pressure receiving area between the small-sized fitting part 8a and the large-sized fitting part 8b, which results in performing a reliable sealing. |
