| 摘要 |
building machines, in particular, controllable pneumatic piercers for sinking of holes of the preset trajectory in the ground at laying and repair of underground service lines. SUBSTANCE: pneumatic piercer has a body with a striking mechanism and a reversing gear, mouthpiece installed on the front end of the body, in which plungers are radially positioned. The space under each plunger individually communicates with a power source. A bush is installed between the mouthpiece and the plungers for radial movement and engagement of its end faces with the end faces of the body and mouthpiece. The end face of the mouthpiece is formed by the clamp on its inner surface shifted relative to the front end face of the bush to its rear end face by a distance shorter than the free travel of the mouthpiece relative to the body. EFFECT: enhanced reliability of device operation, reduced cost of its manufacture and expenditures connected with operation, simplified construction. 4 cl, 9 dwg
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