Abstract: A hydraulic percussion device and method of controlling a working cycle of a percussion piston is provided. A rock breaking machine includes a percussion device provided with a reciprocating piston executing a working cycle. The operation is controlled by means of a control unit generating control signals for independently operable feed and discharge valves of a hydraulic system. The position of the piston is detected by a sensing device.

Abstract: A hydraulic breaking hammer and method of supporting a percussion piston is provided. The breaking hammer includes a percussion device provided with a reciprocating piston. The piston is supported on a frame at its end portions by a first piston bearing element and a second piston bearing element. The second piston bearing element includes a collar sealing element facing towards a working collar of the piston. The piston bearing elements are easily mountable and dismountable separate components.

Abstract: A hydraulic breaking hammer and method of supporting a percussion piston is provided. The breaking hammer includes a percussion device provided with a reciprocating piston. The piston is supported on a frame at its end portions by a first piston bearing element and a second piston bearing element. The second piston bearing element includes a collar sealing element facing towards a working collar of the piston. The piston bearing elements are easily mountable and dismountable separate components.

Abstract: A body of an impact unit, an impact unit and a method of forming a body of an impact unit is disclosed. The body can be an elongated hollow piece including at least two body parts. The body parts are arranged successively in an axial direction of the body and are connected to each other by axial connecting joints. The connecting joints include several slanted fastening screws for connecting the body parts together.

Abstract: The invention relates to a method and apparatus for controlling the fresh-air, input-air, exhaust-air, waste-air and return-air flows, as well as the air pressure in the input-air duct and the air pressure in the exhaust-air duct, in an air-conditioning system which comprises at least input-air and waste-air flow meters (6, 20), input-air and exhaust-air pressure meters (12, 19), an input-air fan (5) with its air-flow control (13), a waste-air or exhaust-air fan (18) with its air-flow control (14), a fresh-air flow meter (15), a heat recovery exchanger (4), closing and control mechanisms for exhaust air and return air, coupled together as an outlet-air mechanism (10), and closing and control mechanisms for fresh air and fresh-air bypass, coupled together as an intake-air mechanism (3).