Patent ID: 6237699
Filing Date: 2001-05-29
Classification: B25D

Abstract:
A rotary hammer which comprises:a tool holder;an air cushion hammering mechanism which comprises a cylinder having one end that is connected to the tool holder, a piston, a ram and a beat piece slidably located in the cylinder so that reciprocation of the piston in the cylinder will cause the ram to reciprocate in the cylinder and thus cause the beat piece to hit a bit located in the tool holder; andwherein the ram has an annular recess in its peripheral surface at the end thereof nearest the piston, in which recess is located an annular seal, the annular seal having an annular seating flap lying on the radially outwardly directed surface of the recess and an annular sealing flap that is joined to the seating flap and extends between the radially outwardly directed surface of the recess and the inner wall of the cylinder at an acute angle to the seating flap.