Patent ID: 6920940

Claim:
A hitch device for attaching farm implements to a tractor, the device comprising two lift arms for supporting at least one farm implement; an actuating cylinder for each lift arm, the actuating cylinder having an output rod defining two chambers inside the actuating cylinder; and a circuit for feeding a fluid to and from said chambers; wherein said circuit comprises, for each said chamber, a feed line for feeding said fluid to the chamber and a feed line for removing said fluid from the chamber, respectively, and also comprises four independent valves; each valve being located along one of said feed lines, and being movable between a closed position and at least one open position respectively closing and opening the relative said feed line, wherein each said valve is a proportional electromagnetic valve, and wherein said actuating cylinder has a first detecting device for detecting a fluid pressure inside each of said chambers to determine a force exerted, in use, on said output rod; electronic control means being provided to selectively control said valves as a function of a signal from said first detecting device.