| 摘要 |
PURPOSE:To prevent unnecessary energy consumption and generation of noise by controlling the transmission of power between a motor and a motion transforming member through a clutch means, and by controlling the pressing of a drill bit coupled to a clutch plate by a mechanically associating means, against a surface to be drilled, with the use of an electromagnet solenoid. CONSTITUTION:During no drilling is made, a clutch plate 26 is positioned on the forward side so as to release the coupling between the plate 26 and a motion transforming member 5. A reduction gear 24 is meshed with a pinion 21, and therefore the rotation of the motor 2 is transmitted to a drill bit 8 through an intermediate shaft 23, a spindle 31 and a key 39. However, the member 5 is isolated so that a piston 4 is not reciprocated. When the bit 8 is made to abut against a surface to be drilled, a striker 33 is retracted to mesh the plate 26 with the member 5 so that the reciprocating motion of the piston 4 is transmitted to the bit 8 through the member 5, an striking member 41 and the striker 33. Thus, when no drilling is made, the piston 4 does not reciprocated so that unnecessary energy consumption may be reduced and the generation of noise may also be prevented.
|
