Parker-hannifin Corporation

Roger Lowman

Jarmo Antero Harsia

Germano Franzoni

A method of controlling a float function of a cylinderhaving a first side and a second side includes connecting the second side of the cylinder to a reservoir; connecting the first side of the cylinder to an output of a pumpand to the reservoir; and supplying an amount of flow from a pump less than an amount supplied by the pump under loaded conditions. A three-position directional control valvehaving a pump port, a reservoir port, a first cylinder port, and a second cylinder port may be provided to effectuate aspects of this method.

Electro-hydraulic system with float function

A cushioned swing circuit provides the reduction of oscillation common in the operation of heavy equipment such as with boom members. The circuit utilizes a transfer of high pressure fluid flow (caused by the inertial of the swing during rapid deceleration) from one leg of the circuit to the other leg of the circuit or to the sump which serves as decompression for the oil that would ordinarily be trapped in the leg. These phenomena create the swing cushioning effect.

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Simpsonville, SC, United States of America

Roger Lowman