| 摘要 |
The invention relates to a ground-drilling device with a basic body and with a drilling head movably mounted in relation thereto in the longitudinally axial direction, wherein a clearance, which is variable in its size owing to the movable mounting, is formed between the drilling head and the basic body, and with a sealing element for sealing the clearance with respect to the surroundings, wherein the sealing element is designed as a valve element which opens when an overpressure prevails inside the clearance, in order to produce a pressure equalization, and which is closed when a negative pressure prevails inside the clearance, in order to prevent a pressure equalization. |
