Hyster Company

Pacific Fluid Systems, Corp.

James I Ott

Delmar G Schwab

Stanley D Nelsen

A hydraulic positioning means is provided which includes means for selectively allowing or prohibiting the flow of the first hydraulic fluid under the operating pressure. It also includes means in the hydraulic positioning means for selectively positioning the workpiece to a plurality of predetermined locations for performing work operations thereon in response to allowing or prohibiting the flow of the first pressurized hydraulic fluid under the operating pressure. Means are also furnished for supplying the first pressurized fluid under the operating pressure to the hydraulic positioning means for such selective positioning of the workpiece. First fluid conduit means transfer the first pressurized fluid at said operating pressure from the pressurized fluid supply means to the hydraulic positioning means. A hydraulic impact load cushioning means is also bifurcatedly provided. The hydraulic impact load cushioning means receives second pressurized hydraulic fluid conveyed thereto from the hydraulic positioning means during the impact loading operations and thereby cushioning the impact transmitted by the workpiece. The cushioning pressure is less than the operating pressure. Second fluid conduit means are furnished for transferring the second pressurized fluid on impact under the cusioning pressure from the hydraulic positioning means to the hydraulic impact load cushioning means.

Method and system for hydraulically positioning and impact load

A hydraulic control arrangement for the lifting and lowering of loads is disclosed. The system is illustrated in an industrial truck and includes a multiple element control valve with timing circuitry to eliminate unwanted transient pressure surges during valve actuation. Series-parallel oil flow paths are provided for directing and controlling oil from the load lifting cylinder to the oil reservoir when the load is being lowered.

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Portland, OR, United States of America

James I Ott