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A pilot-operated valve structure for controlling high pressure fluid flow relative to a pair of cylinders, each having an extend port and a retract port. The valve structure has a pair of pilot-operated 3-way valves, each with a poppet valve member and with pilot valve structure including pilot line

A pilot-operated valve structure for controlling high pressure fluid flow relative to a pair of cylinders, each having an extend port and a retract port. The valve structure has a pair of pilot-operated 3-way valves, each with a poppet valve member and with pilot valve structure including pilot lines directed to the 3-way valves and to the retract ports of the cylinders. The pilot valve has multiple positions including a neutral position whereby pilot pressure may be directed to the 3-way valves for positioning thereof and to the retract ports of the cylinder for holding the pistons in the cylinders retracted or causing retraction of a piston of an extended cylinder. Two alternate positions of the pilot valve cause positioning of one or the other of the 3-way valves to cause extension of the piston in the associated cylinder while the piston in the other cylinder is maintained in retracted position.

대표청구항 ▼

A pilot-operated double 4-way valve for controlling flow relative to a pair of cylinders each having an extend port and a retract port comprising, a pair of 3-way valves each having an inlet port, a control port connectable to a cylinder extend port, a port to reservoir, a bore and a poppet valve me

A pilot-operated double 4-way valve for controlling flow relative to a pair of cylinders each having an extend port and a retract port comprising, a pair of 3-way valves each having an inlet port, a control port connectable to a cylinder extend port, a port to reservoir, a bore and a poppet valve member movable therein, fluid circuit means for connecting said inlet ports to unidirectional flow from a high pressure fluid source, a pair of pilot pistons associated one with each valve member and operable for positioning of the valve member to cause the associated control port to connect to either the inlet port or the reservoir port, a low pressure fluid pilot circuit including a three-position pilot valve intermediate a primary pilot line and separate pilot lines to both of said pilot pistons, said pilot lines also connectable one to each of said cylinder retract ports, and means for positioning said pilot valve either in a first position to connect both pilot lines to said primary pilot line for directing pilot pressure to the pilot pistons and retract ports for positioning a piston in both cylinders in a retract position, in a second position to cause extension of the piston in one cylinder while the piston in the other cylinder remains retracted, or a third position to cause extension of the piston in the other cylinder while the piston in said one cylinder remains retracted.