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In a hydraulic cylinder actuation system for a crane having a conventionally charged main hydraulic pump, a supplemental pump or "charge boost" pump is provided. To efficiently achieve fast actuation speeds of the cylinder, the charge boost pump provides supplemental charge flow in response to a nee

In a hydraulic cylinder actuation system for a crane having a conventionally charged main hydraulic pump, a supplemental pump or "charge boost" pump is provided. To efficiently achieve fast actuation speeds of the cylinder, the charge boost pump provides supplemental charge flow in response to a need in the system. The charge boost pump is driven independently from the main pump or may be driven by the main pump if the main pump is equipped with drive thru capability to provide a variable output and preferably includes a load sensing means for controlling the output.

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[ What is claimed is:] [7.] A hydraulic system for a crane, the system comprising:a hydraulic actuator moveable in extendible and retractable directions;a main pump including a driving pump and an integral charge pump, the integral charge pump providing a flow rate which is fixed relative to the rot

[ What is claimed is:] [7.] A hydraulic system for a crane, the system comprising:a hydraulic actuator moveable in extendible and retractable directions;a main pump including a driving pump and an integral charge pump, the integral charge pump providing a flow rate which is fixed relative to the rotational speed of the driving pump, the main pump being connected in fluid communication with the actuator so that the combined flow rates of the driving pump and integral charge pump are capable of driving the actuator at up to a limited actuation speed beyond which a flow rate capacity of said integral charge pump is exceeded;a charge boost pump connected to provide a supplemental flow of fluid in addition to said combined flow rates to the actuator to drive the actuator at an actuation speed greater than said limited actuation speed.