| 摘要 |
<p>A hammer drill comprising: a housing; a tool holder mounted on the housing; a motor (32) mounted within the housing; a piston (50) and a ram (54), each slideably mounted within the housing; a drive mechanism which converts the rotary output of the motor (32) into a reciprocating motion of the piston (50) within the housing, the ram (54) being reciprocatingly driven by the piston (50) via an air spring (56); a beat piece support structure mounted in the housing forward of the ram (52); a beat piece (58) slideably supported within the beat piece support structure which is repetitively struck by the reciprocating ram (54) and which in turn repetitively strikes an end (402) of a tool wherein the beat piece support structure comprises a seal (70) made from absorbent material such as felt which slidingly engages with the sides of the beat piece. Lubricating oil is provided within the housing, a proportion of which passes through the beat piece support structure and is absorbed by the seal (70).</p> |
