| 摘要 |
<p>A synchronous lifting system with single-rod, single-acting hydraulic cylinders controlled by parallel-connected lift valves having two fluid passages. Hydraulic fluid for extending the actuators is delivered by a hydraulic supply system alternating between the two passages. Each time the supply circuit alternates passages, a fixed volume of hydraulic fluid is transferred by the lift valves to the cylinders causing the rods to lift a proportionate amount. All of the rods extend by approximately the same increment each time the supply circuit alternates passages. Because the rods all extend the same increment each cycle, the load is lifted evenly and the need for height sensors or transducers is eliminated.</p> |
