| 摘要 |
The invention relates to a hydraulically operated impact device, such as a percussion hammer or some other breaking apparatus, comprising a control valve (6) for controlling pressure fluid supplied to and from the percussion piston (1) so that the direction of motion of the piston (1) can be changed in accordance with the cycle of operation of the impact device. According to the inventive idea, when the control valve (6) is in the impact position, the impact device is provided with a closed space that is partly bordered by the control valve and the percussion piston. The percussion piston (1) comprises a section which communicates with said space and which has a larger diameter than the upper end of the piston. The control valve and the percussion piston are thus able to move in the same direction until a connection is opened from this closed space to the upper end of the percussion piston (1). <IMAGE> |
