A HYDRAULIC SYSTEM AND A METHOD FOR MOVING AN IMPLEMENT OF A WORKING MACHINE
First Claim
1. A hydraulic system for moving an implement of a working machine,the hydraulic system comprising a hydraulic cylinder with a cylinder and a piston which is adapted to move in the cylinder to thereby move the implement relative to a body structure of the working machine, and an actuator pump arranged to provide hydraulic fluid to the hydraulic cylinder, the hydraulic cylinder having a first port and a second port adapted to be in fluid communication with the actuator pump,the hydraulic cylinder and the actuator pump being arranged so that the hydraulic cylinder is directly controlled by the actuator pump so that the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, the hydraulic system further comprising a hydraulic accumulator for suspension of the implement, which hydraulic accumulator is arranged to be selectively connectable to the first port,the hydraulic system further comprising a further pump in addition to the actuator pump, the hydraulic accumulator being arranged to be pressurised by the further pump.
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Accused Products
Abstract
A hydraulic system for moving an implement of a working machine includes a hydraulic cylinder with a cylinder and a piston which is adapted to move in the cylinder to thereby move the implement relative to a body structure of the working machine, and an actuator pump arranged to provide hydraulic fluid to the hydraulic cylinder, the hydraulic cylinder having a first port and a second port adapted to be in fluid communication with the actuator pump, the hydraulic cylinder and the actuator pump being arranged so that the hydraulic cylinder is directly controlled by the actuator pump so that the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, the hydraulic system further including a hydraulic accumulator for suspension of the implement, which hydraulic accumulator is arranged to be selectively connectable to the first port, the hydraulic system further including a further pump in addition to the actuator pump, the hydraulic accumulator being arranged to be pressurised by the further pump.
5 Citations
25 Claims
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1. A hydraulic system for moving an implement of a working machine,
the hydraulic system comprising a hydraulic cylinder with a cylinder and a piston which is adapted to move in the cylinder to thereby move the implement relative to a body structure of the working machine, and an actuator pump arranged to provide hydraulic fluid to the hydraulic cylinder, the hydraulic cylinder having a first port and a second port adapted to be in fluid communication with the actuator pump, the hydraulic cylinder and the actuator pump being arranged so that the hydraulic cylinder is directly controlled by the actuator pump so that the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, the hydraulic system further comprising a hydraulic accumulator for suspension of the implement, which hydraulic accumulator is arranged to be selectively connectable to the first port, the hydraulic system further comprising a further pump in addition to the actuator pump, the hydraulic accumulator being arranged to be pressurised by the further pump.
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12. A method for moving an implement of a working machine comprising a hydraulic cylinder with a cylinder and a piston which is adapted to move in the cylinder to change the length of the hydraulic cylinder to move the implement, the hydraulic cylinder presenting a first port and a second port adapted to be in fluid communication with an actuator pump, the working machine further comprising a hydraulic accumulator for suspension of the implement, which hydraulic accumulator is arranged to be in free fluid communication with the first port, the method comprising
disconnecting the hydraulic accumulator from the first port, moving fluid to the second port via the actuator pump, whereby the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, so as to shorten the hydraulic cylinder to lower the implement relative to a body structure of the working machine, pressurising the hydraulic accumulator by a further pump which is provided in addition to the actuator pump, moving fluid to the first port by means of the actuator pump, whereby the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, so as to extend the hydraulic cylinder to raise the implement relative to the body structure, and determining whether to provide a free fluid communication between the hydraulic accumulator and the first port.
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21. A control unit for a hydraulic system for moving an implement of a working machine comprising a hydraulic cylinder with a cylinder and a piston which is adapted to move in the cylinder to change the length of the hydraulic cylinder to move the implement, the hydraulic cylinder presenting a first port and a second port adapted to be in fluid communication with an actuator pump, the working machine further comprising a hydraulic accumulator for suspension of the implement, which hydraulic accumulator is arranged to be in free fluid communication with the first port, the control unit being configured to
to control a suspension control valve (732) to disconnect the hydraulic accumulator from the first port, to control the actuator pump so as to move fluid to the second port via the actuator pump, whereby the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, so as to shorten the hydraulic cylinder to lower the implement relative to a body structure of the working machine, to control a further pump which is provided in addition to the actuator pump so as to pressurise the hydraulic accumulator, to control the actuator pump so as to move fluid to the first port by means of the actuator pump, whereby the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, so as to extend the hydraulic cylinder to raise the implement relative to the body structure, and to determine whether to provide a free fluid communication between the hydraulic accumulator and the first lifting actuator port.
Specification