Lift control for implement frame

Abstract From the Canadian patent

Frame sections on an implement are supported above the ground by lift wheel assemblies having positive mechanical depth stops and series connected lift cylinders. A pressure responsive bypass valve is installed in series with an orifice between the ports of the series connected cylinders. The valve permits the corresponding cylinder to be retracted and positively held against the depth stop and allows bypass flow to the next cylinder in series for continued retraction of the next cylinder until it bottoms against the stop. The orifice protects the bypass valve poppet from damaging high flows and controls the rate of descent of the other frame sections onto the remaining stops. The system …