Abstract: A harvester head having at least one hydraulic actuator with a cylinder and a piston. The hydraulic actuator having at least a cylinder chamber and a piston rod chamber, both chambers being connected to a hydraulic circuit. The piston separating the cylinder chamber and the piston rod chamber, a cavity provided in the piston, hydraulically connecting the cylinder chamber with the piston rod chamber and a check valve in connection with the cavity that allows hydraulic medium flow in an opening direction of the check valve.

Abstract: A harvester head having at least one hydraulic actuator with a cylinder and a piston. The hydraulic actuator having at least a cylinder chamber and a piston rod chamber, both chambers being connected to a hydraulic circuit. The piston separating the cylinder chamber and the piston rod chamber, a cavity provided in the piston, hydraulically connecting the cylinder chamber with the piston rod chamber and a check valve in connection with the cavity that allows hydraulic medium flow in an opening direction of the check valve.

Abstract: A bearing arrangement in an actuator of a forest machine comprising a frame of the actuator, which frame defines a first opening. The bearing arrangement also comprises a bushing, at least part of the bushing arranged in the first opening, the bushing defining a second opening, at least part of an axle and/or a bearing being arranged in the second opening, the axle or bearing being arranged stationary or movable in relation to the bushing, and the bushing being removable from the frame of the actuator. Further, a method for maintaining an actuator of a forest machine, the actuator comprising a bearing arrangement of the described type. In the method, a second, corresponding bushing is provided, which is fitted for said first opening; said bushing is removed from the frame of the actuator, wherein said first opening is exposed; and said second bushing is installed in said first opening.

Abstract: A bearing arrangement in an actuator of a forest machine comprising a frame of the actuator, which frame defines a first opening. The bearing arrangement also comprises a bushing, at least part of the bushing arranged in the first opening, the bushing defining a second opening, at least part of an axle and/or a bearing being arranged in the second opening, the axle or bearing being arranged stationary or movable in relation to the bushing, and the bushing being removable from the frame of the actuator. Further, a method for maintaining an actuator of a forest machine, the actuator comprising a bearing arrangement of the described type. In the method, a second, corresponding bushing is provided, which is fitted for said first opening; said bushing is removed from the frame of the actuator, wherein said first opening is exposed; and said second bushing is installed in said first opening.