| 摘要 |
Double acting cylinders on wheel lift structures of an agricultural implement are connected in parallel and include pilot operated check valve structure connected to the base ends of the cylinders to maintain timing of the lift wheel structure even under large differential loads without a rockshaft or other mechanical timing device extending between the wheel structures. The check valve structure prevents unwanted cylinder retraction and provides cylinder lock-up for transport without need for additional valves. When pressure is applied to the rod ends of the cylinders, the check valve structure allows fluid to flow from base ends. Orifices are inserted at the base ends of the cylinders 86 to provide optimum breakoff pressure for the check valves.
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