| 摘要 |
<p>A rotary hammer comprising: a housing; a motor mounted within the housing (2); a tool holder (4) rotatably mounted on the housing (2) for holding a cutting tool; a striker (142) mounted in a freely slideable manner within the housing for repetitively striking, at a relatively low frequency, an end of a cutting tool when a cutting tool is held by the tool holder (4), wherein the striker is reciprocatingly driven by the motor (18), when the motor (18) is activated, via a drive mechanism; wherein the striker (142) strikes an end of a cutting tool via a beat piece (120) slideably mounted within the housing (2); characterised in that the beat piece is capable of being rotatingly driven by the motor whereby there is further provided a pair of co-operating ratchet plates (151,154), the first ratchet plate (154) being rigidly connected to the beat piece (120) and the second ratchet plate (151) being connected to the housing (4) and which, when the first and second ratchet plates (151,154) are engaged and the beat piece (120) is rotatingly driven by the motor, superimpose high frequency impacts onto the low frequency impacts generated by the striker (142), when the striker is being reciprocatingly driven by the motor.</p> |
