US Patent 7427092 Hydraulic synchronization of slide-out for recreational vehicle

A hydraulic synchronization system for a slide-out portion of a recreational vehicle has at least two cylinders spaced apart and reversed in orientation with respect to one another. The bore sides of the cylinders are connected and the rod sides of the cylinders are connected such that hydraulic fluid is pumped from the rod side of one cylinder to the rod side of the other cylinder and from the bore side of one cylinder to the bore side of the other cylinder upon extension and retraction of the slide-out portion to keep the slide-out portion synchronized.