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 control unit controls a tree stem processing tool pivotably mounted to an articulated boom in such a way that orientation of the tool is changed when the tool is controllably rotated about a rotation axis that is oriented substantially vertically. the articulated boom being rotatably connected to a mobile work machine, The control unit is adapted to automatically apply a control mode in the control unit in which control mode a power-driven operation is controlled according to a predetermined dependency in such a way that one or more operating parameters influencing the power-driven operation vary as a function of a prevailing separation or a prevailing distance determined in relation relating to a predetermined hazard direction or predetermined hazard trajectory associated with the tool.

Abstract: A log processing head with a top knife and moveable feed means and delimbing and/or debarking means pushing a log against the top knife by means of actuators. In order to allow the top knife to follow the contour of the log without damaging a pin holding the knife, a pivot joint is used between the knife and the connection of the pin on the structure.

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 log processing head with a top knife and moveable feed means and delimbing and/or debarking means pushing a log against the top knife by means of actuators. In order to allow the top knife to follow the contour of the log without damaging a pin holding the knife, a pivot joint is used between the knife and the connection of the pin on the structure.

Abstract: An automatic track tensioning system is provided for use with a track-type work vehicle for automatically tensioning an endless track chain of the work vehicle.

Abstract: A control coupling of pressurized medium in a delimbing and cutting apparatus, provided for feeding members and for changing their feeding speed, said control coupling comprising at least: a first motor and a second motor that are coupled in parallel and drive a feeding member a third motor that is a multicapacity motor comprising a first half-motor and a second half-motor and that is coupled in series with the first motor and drives a feeding member; a fourth motor that is coupled in series with the second motor and drives a feeding member; first valve members that for the purpose of free rotation allow the feedback of the pressurized medium exiting the third motor to the first half-motor; and first control members that monitor the pressure of a first line and couple the first valve members to free rotation if said pressure is lower than the set value.

Abstract: An automatic track tensioning system is provided for use with a track-type work vehicle for automatically tensioning an endless track chain of the work vehicle.

Abstract: A control coupling of pressurized medium in a delimbing and cutting apparatus, provided for feeding members and for changing their feeding speed, said control coupling comprising at least: a first motor and a second motor that are coupled in parallel and drive a feeding member a third motor that is a multicapacity motor comprising a first half-motor and a second half-motor and that is coupled in series with the first motor and drives a feeding member; a fourth motor that is coupled in series with the second motor and drives a feeding member; first valve members that for the purpose of free rotation allow the feedback of the pressurized medium exiting the third motor to the first half-motor; and first control members that monitor the pressure of a first line and couple the first valve members to free rotation if said pressure is lower than the set value.

Abstract: An arrangement in a circulation lubrication system include a lubricating oil tank, pressure pipe lines for supplying oil to parts to be lubricated, return pipe lines for returning the oil from the parts to be lubricated to the oil tank, and a mechanism configured to pump oil into the pressure pipe lines and maintaining a desired state of lubrication. The mechanism configured to pump the oil into the pressure pipe lines may include a circulation lubrication pump and a suction duct through which the lubricating oil flows out of a lubricating oil tank, an underpressure tank coupled to the suction duct leading off from the lubricating oil tank, to the suction side of the circulation lubrication pump. The underpressure tank is a tank which allows the water contained in the oil to evaporate. To prevent cavitation of the circulation lubrication pump, the underpressure tank is placed substantially higher than the lubricating oil tank.

Abstract: An arrangement in a circulation lubrication system includes a lubricating oil tank, pressure pipe lines for supplying oil to parts that are to be lubricated, return pipe lines for returning the oil from the parts that are to be lubricated to the oil tank, and a mechanism for pumping oil into the pressure pipe lines and maintaining a desired state of lubrication. The lubricating oil tank has a rotationally symmetric structure; and a return duct, positioned at the center axis of the rotationally symmetric structure, is configured to extend below the surface of the oil in the lubricating oil tank. A return flow through the return duct passes through a dividing element to a mechanism configured to separate impurities from the oil.