PNEUMATIC PERCUSSION DEVICE FOR MAKING HOLES IN GROUND Russian patent published in 1997 - IPC

FIELD: construction machinery; applicable in making holes in ground, for instance, trenchless laying of underground services lines, driving into ground of metallic pipes and sheet piles. SUBSTANCE: technical problem of the invention is solved by increase of mean pressure in working chambers over path of hammer. To increase mean pressure along the path, the device is provided with pressure control member in chamber of idle stroke chamber. This member communicates idle stroke chamber of hammer with ambient atmosphere in its motion in direction, of impact or with compressed air line on the larger part of idle stroke. As a result, prior to impact, no air pad is formed in idle stroke chamber to affect speed of hammer, and in idle stroke, hammer motion is increased. So, without increase of dimensions of device, energy of impact rises to increase production efficiency of device. EFFECT: higher energy of impact of pneumatic percussion device. 3 cl, 3 dwg