Powered hammer

POWERED HAMMER A powered rotary hammer or chisel hammer has a hammer mechanism with a ram reciprocatingly movably mounted in a guide tube section and comprising an outer circumferential surface in which a vent channel is provided which connects the front end of the circumferential surface with its rear end and which is interrupted by a 5 radially outwardly projecting sealing portion, and has a piston reciprocatingly drivable by means of a motor of the hammer which piston in operation generates a varying air cushion between the ram and the piston surface facing the ram to cause an impact on the tool bit inserted into the tool holder of the hammer by movement of the ram towards the tool bit wherein the space between the ram and the surface of the piston 10 facing the ram is temporarily connected to ambient air through the vent channel after causing the impact. The vent channel on the outer circumferential surface of the ram is helically shaped. P-AU-PR1189 co CNJ LCli C%4 U') co U')