| 摘要 |
PROBLEM TO BE SOLVED: To provide a hammering device, automatically increasing the striking force when rock or the like to be crushed is hard. SOLUTION: In this hammering device, a piston 2 having a pressure receiving surface 2u for hammering on which fluid pressure such as oil pressure acts in hammering and a pressure receiving surface 2w for reversal on which the fluid pressure acts in reversal is installed in a cylinder 1 so as to be moved forward and backward in the axial direction. An additional second pressure receiving surface 2v for hammering enabling pressurizing action on the fluid pressure is formed on the piston 2, and a switching means 101 is installed in the device to switch between a state in which the fluid pressure acting on the additional pressure receiving surface 2v can be supplied thereto and a state in which the fluid pressure cannot be supplied thereto. When the rebound of the piston 2 by a reaction caused when the piston 2 hits a chisel 3 at the movement end of the piston 2 is larger than a specified value, the switching means 101 switches the state to one in which the fluid pressure can be supplied to the additional pressure receiving surface 2v for hammering. COPYRIGHT: (C)2007,JPO&INPIT
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