Abstract: Hydraulic percussion hammer, in which a motion of a percussion piston (1) is controlled by a main valve (3), the control motion of which is controlled by a separate control valve (9) in such a way that the main valve changes its state, when the pressure acting on the control valve (9) rises to a predetermined value. The percussion hammer comprises a controller (21) mounted in its return duct (13), by which controller an outflow of pressure fluid from the percussion hammer can be adjusted in such a way that the filling rate of a pressure accumulator (7) and thus the length of a return motion of the percussion piston (1) are proportional to the flow resistance provided by the controller (21).

Abstract: The invention relates to a hydraulic percussion hammer comprising a piston (1), a pressure accumulator (7) in the high pressure circuit, a main valve (8) alternately conducing a high and low pressure to at least one of the pressure surfaces (2,4) of the piston (1) for making the piston (1) move reciprocally, and a tool (3) which the piston (1) strikes, and, for the purpose of controlling the main valve (8), a control pressure valve (9) which opens when the pressure exceeds a set value. According to the invention, the control pressure valve (9) is placed in such a way that the spindle (27) of the control pressure valve (9) is connected from one end to the high pressure circuit of the hydraulic percussion hammer.

Abstract: The invention relates to a hydraulic impact hammer, comprising a protective casing made of two side plates, and provided with attenuation elements for eliminating the noise and vibration caused by the impact hammer. According to the invention, the attenuation elements (5, 6) are arranged in the side plates (1, 2) of the protective casing, so that the attenuation elements (5, 6) can be compressed in at least three directions (X, Y, Z) of the housing (4) while fastening the side plates (1, 2) to each other.

Abstract: A hydraulic impact hammer comprises a protective casing, a hydraulically operated piston and a member for guiding the piston, and an impact member and a member for guiding the impact member. The piston-guiding member and the member guiding the impact member are made separate with respect to each other in order to prevent propagation of the tension wave reflected from the impact member. However, the piston-guiding member and the member guiding the impact member are each connected to the protective housing through at least one attenuating element.

Abstract: A hydraulic impact hammer comprises a protective casing, a hydraulically operated piston and a member for guiding the piston, and an impact member and a member for guiding the impact member. The piston-guiding member and the member guiding the impact member are made separate with respect to each other in order to prevent propagation of the tension wave reflected from the impact member. However, the piston-guiding member and the member guiding the impact member are each connected to the protective housing through at least one attenuating element.