Abstract: A compressed air nailer comprises a driving tappet connected to a compressed air supply and configured to drive in a fastener. A triggering apparatus is configured to trigger a driving process and a working piston is coupled to a driving tappet. A safety actuator is configured to be displaced between a locked position and an open position, wherein when in the locked position, the safety actuator is configured to inhibit the triggering of the driving process when an actuation of the triggering apparatus occurs. The compressed air nailer further comprises a throttle and a safety control chamber configured to be aerated and deaerated by the throttle. A counterforce generator is configured to generate a counterforce that acts on the safety actuator and is directed in an opposite direction from the actuating force. The counterforce is linearly dependent on an operating pressure of the compressed air nailer.

Abstract: Provided is a method of controlling a pitch angle of at least one blade of a wind turbine by use of a hydraulic system, the hydraulic system including at least one reservoir configured to store a hydraulic fluid, and at least one pump configured to supply the hydraulic fluid from the reservoir to at least one accumulator, if a hydraulic fluid pressure in the accumulator falls below a lower threshold value and till the hydraulic fluid pressure in the accumulator exceeds an upper threshold value. The accumulator is configured to store the pressurized hydraulic fluid supplied by the pump and to supply the pressurized hydraulic fluid to at least one pitch control cylinder of the hydraulic system via at least one output valve of the hydraulic system. The pressurized hydraulic fluid in the pitch control cylinder drives at least one piston to change the pitch angle of the blade.

Abstract: There is provided a pitch control system (210) for controlling a pitch force system (220) for pitching a blade (103) of a wind turbine (100), the pitch control system (210) being arranged for activating (682) an auxiliary pitch force subsystem (224) at an initiation point in time where a main pitch force is sufficient to pitch the blade (103) into a target pitch value. An advantage thereof may be that tracking of a target pitch value may be improved and the impact on the pitch force system (220) may be reduced. In aspects, there is furthermore presented a hydraulic pitch system (206), a wind turbine (100), a method and a computer program product.

Abstract: An asymmetric volume booster assembly includes an actuator movable in a first direction and a second direction, a first booster in fluid communication with the actuator, and a second booster in fluid communication with the actuator. The first booster includes a first supply passage and a first exhaust passage, wherein the first supply passage supplies fluid to the actuator and the first exhaust passage exhausts fluid from the actuator. The first exhaust passage is configured to produce a first fluid flow resistance. The second booster includes a second supply passage and a second exhaust passage, wherein the second supply passage supplies fluid to the actuator and the second exhaust passage exhausts fluid from the actuator. The second exhaust passage is configured to produce a second resistance to fluid flow. The first fluid flow resistance is greater than the second fluid flow resistance, such that the actuator moves substantially symmetrically in the first direction and the second direction.

Abstract: In an electrohydraulic control unit for rotor blade adjustment of a wind farm via a hydraulic cylinder, the hydraulic cylinder has one piston chamber and one piston rod chamber. Via an inflow valve assembly, a pressure fluid connection can be established between the pump and the piston chamber, while via an outflow valve assembly, a pressure fluid connection can be established between the piston rod chamber and the tank. Each valve assembly has at least two parallel-connected switch valves, which open and can be closed in various combinations in order to establish a desired position of the hydraulic cylinder. This control unit makes precise regulation of the rotor blade possible.

Abstract: An asymmetric volume booster assembly includes an actuator movable in a first direction and a second direction, a first booster in fluid communication with the actuator, and a second booster in fluid communication with the actuator. The first booster includes a first supply passage and a first exhaust passage, wherein the first supply passage supplies fluid to the actuator and the first exhaust passage exhausts fluid from the actuator. The first exhaust passage is configured to produce a first fluid flow resistance. The second booster includes a second supply passage and a second exhaust passage, wherein the second supply passage supplies fluid to the actuator and the second exhaust passage exhausts fluid from the actuator. The second exhaust passage is configured to produce a second resistance to fluid flow. The first fluid flow resistance is greater than the second fluid flow resistance, such that the actuator moves substantially symmetrically in the first direction and the second direction.

Abstract: A hydraulically operated percussion hammer comprising a percussion piston that reciprocates by means of the pressure of the pressure fluid, a main valve that is controlled by the position of the percussion piston and that guides the pressure fluid to the percussion piston in order to provide a reciprocating motion, and a pressure control valve that is placed in an outlet duct for pressure fluid and that prevents the flow of the pressure fluid from the percussion apparatus before the pressure of the pressure fluid in the inlet duct exceeds the set value of the pressure control valve. The percussion apparatus comprises a separate by-pass duct which allows the pressure fluid to flow from the pressure chamber of the percussion piston past the pressure control valve to the outlet duct until the percussion piston has reached a certain point during its return motion.

Abstract: The present invention relates to a valve control apparatus for operating a working piston, comprising a main valve spool including a smaller piston face subjected to compressed air from a reservoir and a larger piston face facing a main control space, further comprising an auxiliary valve spool having a first effective area which can be connected by a trigger valve to atmosphere or to a compressed air reservoir to displace the main control spool into an open position, and having a second effective area which is connected to a piston stroke chamber for displacing the main valve spool into a closed position, wherein the auxiliary valve spool is returned when the pressure acting on its second effective area falls below a predetermined value, wherein this effective area is connected to a shift valve which communicates with atmosphere when the trigger is not actuated and which is closed when being actuated and wherein the trigger is provided to move a first length of travel and a second length of travel to actuate