| 摘要 |
PURPOSE:To enable drilling even a tile and the like efficiently and neatly by adjusting the strength of a striking impact without any change of a rotational speed and a striking frequency in a hammer drill as a tool for drilling a concrete. CONSTITUTION:A motor 2 is provided in the rear part of a drill housing 1 and a pinion 21 is fitted to the output shaft 20 of the motor 2. On the other hand, a spindle 31 is provided within the front end part of the housing 1 and a gear 32 to be engaged with a pinion 25 is fitted to the external surface of the rear end part. A piston 4 and a hammer 41 are provided aft of a striker 33. When a striking impact is adjusted, an adjustment handle 14 is turned, thereby causing the advance of the piston 4 and the change of a distance between the piston 4 and the striker 33. Then, there appears a difference in speed for the hammer 41 following the reciprocal motion of the piston 4 via an air spring to hit the striker 33.
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