Portable percussive ramming machine - has housing around cylinder with pressure-equalising ports in cylinder top dead centre

摘要

The ramming machine has a housing (1) accommodating cylinder (2) resulting in ring gap (3) between the two elements. The gap (3) is connected with space (4) accommodating the crank assembly (5), carrying the piston (6), divided from the hammer (8) by air cushion (9). To achieve pressure equalizing in the air cushion when the piston is in its top and bottom dead centres the machine is fitted with a set of openings (12) which serve for venting and admission of air from and to the air cushion (9). The openings (12) are provided in the side walls of the cylinder (6). The cylinder (2) has in the zone of the top dead centre a port (14) connecting the air cushion (9) with the gap (3). The port becomes uncovered, when the bottom face (15) is in the top dead centre.