| 摘要 |
A hand drill including a housing (2), a rotary drive (8-15) arranged in the housing (2) for driving a chuck (6) provided at a front, in the drilling direction, end of the housing and in which a drill or a chisel tool is received, a compressed air-operated hammer mechanism having a pneumatic cylinder (22), a die member (15) for imparting axial blows to the drill or chisel tool, and a percussion piston (30) displaceable in the pneumatic cylinder 922) upon being impinged by compressed air for intermittently applying axial blows to the die member (15), and a reversing valve for connecting the hammer mechanism (22) with a source of compressed air, integrated in the percussion piston (30), and having a plurality of recesses and bores (46-52) alternatively operationally connectable with at least one inlet opening (23) and at least one discharge opening (24) of the pneumatic cylinder (22) for feeding the compressed air into the pneumatic cylinder (22) and for discharging the compressed air therefrom.
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