A valve device for a sanitary fitting having at least two control elements which are movable relative to one another and on which at least two inlet channels and at least one control channel are formed is described. This is called inverse multiplexing. A fastening member passes through the first and second apertures coupling the first strap and the platform and thereby forming two separate passageways. Thus allowing the dynamic height adjustable means to raise and lower the trailer frame above and below the centerline of the wheels, which aids loading and unloading of cargo onto the trailer.