Self-propelled pneumatic or hydraulic ram

摘要

The subject matter of the invention is a self-propelled pneumatic or hydraulic ram with an essentially tubular housing 1 as well as a ram head 2 arranged at the front side of the housing 1 and having a front end face 3 and a circumferential surface 5 widening towards the rear, a percussion bolt which can reciprocate axially in the housing 1 between two stops transmitting its percussion energy to the ram head 2. So that reasonable advance of the ram is also possible at large bore diameters and so that the advance can also take place with little soil cover, it is proposed with the invention that the circumferential surface 5 of the ram head 2 be at least partly flattened in the longitudinal direction at opposite circumferential sides 6 relative to the circumferential sides 6', at right angles thereto, of the circumferential surface 5. In this arrangement, the tubular housing 1 can be additionally surrounded by a sleeve 8. <IMAGE>