| 摘要 |
PROBLEM TO BE SOLVED: To prevent dust from invading into a housing of a pavement crusher. SOLUTION: In a hammer drill having a housing, a tool holder mounted on the housing, a motor 32, a slidably-mounted piston 50 and ram 54, a drive mechanism for converting rotational output of the motor 32 into reciprocal motions of the piston, a beat piece support structure mounted in the housing in front of the ram, and a beat piece which is the beat piece 58 slidably supported in the beat piece support structure and repetitively strikes an end 402 of a tool by being repetitively struck by the reciprocating ram, the beat piece support structure has a seal 70 formed by an absorbing material which is connected to slide along a side section of the beat piece. COPYRIGHT: (C)2008,JPO&INPIT
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