| 摘要 |
Apparatus for sinking a borehole in the ground comprises a self-propelled displacement hammer having a tubular housing containing a percussion mechanism for driving the housing forwards, a follow-up tube arranged to be attached to the rear end of the housing and a bracing cable device arranged to be mounted on the rear end of the follow-up tube for exerting a push on the tube from a bracing cable. Preferably the bracing cable device includes a cable guide sheave which is journalled on a bearing piece at the rear end of the tube and the bearing piece also carries a clamping device for clamping a pulling rope, which in operation of the apparatus has one end fixed to the rear end of the housing and which extends upwards through the follow-up tube for withdrawing the hammer upwards through the follow-up tube from the borehole. |
