Grove US LLC

Kidde Industries, Inc.

Claude R Zimmerman

Henry D Barthalow

William E Hull

The telescoping system includes a first and second fluid motor. The first fluid motor includes a first cylinder and a second cylinder nested in the first cylinder. The second fluid motor includes the second cylinder and a piston disposed in the second cylinder. The second cylinder has a double barrel outer wall forming a hydraulic fluid passageway. A hydraulic control system in the telescoping system includes a single control valve, solenoid valves, and holding valves, and controls extension and retraction of the telescoping system.

Telescoping system with multi-stage telescopic cylinder

The telescoping system includes a first fluid motor and a second fluid motor. The first fluid motor includes a first extension chamber and a first retraction chamber, and the second fluid motor includes a second extension chamber and a second retraction chamber. A hydraulic control system in the telescoping system controls the supply of hydraulic fluid to the first fluid motor and between the first fluid motor and the second fluid motor such that the first and second fluid motors operate independently.

Telescoping system with multiple single-stage telescopic cylinders

An electro-hydraulic operating system for an extensible boom includes one or more hydraulic cylinders for imparting relative motion between the boom sections to retract the boom according to an electronically stored program of sequences of movement and speeds. A source of pressurized hydraulic fluid is fed through appropriate control valves which include solenoid valves in fluid communication with a source of pressurized hydraulic fluid. The solenoid control valves are supplied with control currents proportional to the desired flow rates of fluid to the hydraulic cylinders in order to achieve speed and position control according to the stored program. A metering valve structure is provided for operation in conjunction with the solenoid control valves. The metering valve includes an associated pilot valve which receives variable pressure signals from the solenoid control valves to achieve the metering of fluid to the hydraulic cylinders in proportion to the characteristics of the control current supplied to the solenoid valves. The electrical control signals are such that the hydraulic cylinders may move associated boom sections at gradually increasing speeds during a starting period of any cycle of movement of the section, at a substantially constant speed during an intermediate period of movement and at a gradually decreasing speed during a stopping period preceding the end of the cycle of movement, thereby providing soft start and soft stop of the sections.

Electro-hydraulic operating system for extensible boom crane

The metering valve includes a housing assembly defining a metering cavity therein. At least one inlet port supplies fluid to be metered to the cavity, and at least one output port outputs metered fluid from the cavity. A valve seat in the cavity is disposed between the input and output ports, a pilot chamber and a pilot port to the pilot chamber. A control element in the pilot chamber is displaceable in proportion to the pressure of pilot fluid input to the pilot port. A valve spool is mounted for reciprocating movement in the metering cavity, and the spool is coupled to the control element and displaceable therewith. The spool has a metering flange for operative engagement with the valve seat in the cavity. The position of the metering flange with respect to the valve seat controls variable flow rates of fluid between the input port and output port of the valve housing assembly. A thermal relief valve is disposed within the spool and movable therewith, and the thermal relief valve vents fluid in the cavity through the input port when the pressure of fluid in the cavity exceeds a predetermined limit.

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Mercersburg, PA, United States of America

Claude R Zimmerman