Apparatus for operating a machine work tool

An apparatus for operating a work tool of a machine, the apparatus comprising:

• a cylinder comprising a cylinder wall extending between first and second cylinder ends;
• a piston comprising a piston rod attached to a piston head, the piston head being mounted in the cylinder such that the piston is moveable relative to the cylinder;
• a secondary rod extending from the first cylinder end and terminating with a secondary head, the secondary rod and the secondary head being within the cylinder and the piston;
• an actuator fluid system for moving the piston relative to the cylinder, the actuator fluid system having at least one fluid chamber inside the piston and at least one fluid pump for selectively supplying fluid via at least one actuator conduit to the at least one fluid chamber to move the piston relative to the cylinder;
• and
• a gas spring arrangement for biasing the piston head away from the first cylinder end, the gas spring arrangement comprising:
• a first gas chamber extending between the first cylinder end and the piston head and a second gas chamber extending between the piston head and the second cylinder end wherein the second gas chamber is outside of the piston and extends from the piston head towards the second cylinder end between the piston rod and cylinder wall, the first gas chamber and the second gas chamber each having a variable volume based upon the position of the piston head in the cylinder;
• and
• a gas connection arrangement fluidly connecting the first gas chamber to the second gas chamber and configured to enable gas to flow between the first gas chamber and the second gas chamber;
• and
• a secondary head mounted inside the piston rod to form a first piston chamber between the secondary head and piston head and a second piston chamber between the secondary head and an outer piston end of the piston rod.

A method of operating a machine comprising a work tool and an apparatus mounted to the work tool, the apparatus comprising:

• a cylinder comprising a cylinder wall extending between first and second cylinder ends;
• a piston comprising a piston rod attached to a piston head, the piston head being mounted in the cylinder;
• a secondary rod extending from the first cylinder end and terminating with a secondary head, the secondary rod and the secondary head being within the cylinder and the piston;
• an actuator fluid system for moving the piston relative to the cylinder having at least one fluid chamber inside the piston and at least one fluid pump for selectively supplying fluid via at least one actuator conduit to the at least one fluid chamber to move the piston relative to the cylinder;
• and
• a gas spring arrangement comprising:
• a first gas chamber extending between the first cylinder end and the piston head and a second gas chamber extending between the piston head and the second cylinder end, wherein the second gas chamber is outside of the piston and extends from the piston head towards the second cylinder end between the piston rod and cylinder wall;
• and
• a gas connection arrangement fluidly connecting the first gas chamber to the second gas chamber,
• wherein the method comprises:
• biasing the piston head away from the first cylinder end by a gas in the gas spring arrangement;
• and
• moving the piston head such that the first gas chamber and the second gas chamber vary in volume and gas is transmitted from the first gas chamber to the second gas chamber via the gas connection arrangement, the gas connection arrangement comprising at least one gas passageway extending through the piston head.