Abstract: The knuckle boom includes a hoist boom having a proximal end pivoted to a machine base, and a stick boom having a proximal end pivoted to a distal end of the hoist boom. At least one hydraulic hoist cylinder is mounted between the machine base and the hoist boom, and at least one hydraulic stick cylinder is mounted between the hoist boom and the stick boom. A hydraulic circuit supplies hydraulic oil to the cylinders, and provides an oil flow path between working ends of the cylinders so as to transfer a slug of pressurized hydraulic oil between the working ends. In one embodiment, reaching movement is controlled by a pump connected to control transferring of the slug between the hoist and stick cylinders. The pump determines which cylinder receives which portion of the slug of oil, and thereby controls the angle between the booms, thereby producing reach.

Abstract: The knuckle boom includes a hoist boom having a proximal end pivoted to a machine base, and a stick boom having a proximal end pivoted to a distal end of the hoist boom. At least one hydraulic hoist cylinder is mounted between the machine base and the hoist boom, and at least one hydraulic stick cylinder is mounted between the hoist boom and the stick boom. A hydraulic circuit supplies hydraulic oil to the cylinders, and provides an oil flow path between working ends of the cylinders so as to transfer a slug of pressurized hydraulic oil between the working ends. In one embodiment, reaching movement is controlled by a pump connected to control transferring of the slug between the hoist and stick cylinders. The pump determines which cylinder receives which portion of the slug of oil, and thereby controls the angle between the booms, thereby producing reach.

Abstract: A self-cleaning nozzle includes a piston with a cleaning tip slidably mounted in the interior of a cylinder having two ends and a side wall, the cylinder having first, second and third openings into its interior, the second opening being intermediate the first and third openings. First and second sources of fluid are provided, the former communicating in fluid-flow relationship with the piston and the interior of the cylinder via the second opening. The second source communicates in fluid-flow relationship with the piston and the interior of the cylinder via the third opening. When the force exerted by the pressure of the second source is greater than the force exerted by the pressure of the first source, the piston moves to the cleaning position where the cleaning tip is passed into the first opening, cleaning out any foreign object therein.