GB865952A - Improvements in or relating to fluid pressure operated apparatus - Google Patents

Abstract

865,952. Adjusting body height. ENGINEERING RESEARCH & APPLICATION Ltd. March 10, 1959 [March 26, 1958], No. 9674/58. Class 108(2). A levelling valve for a vehicle suspension system has inlet ports 23, 24 an exhaust port 25 and a supply port 26. A height sensing rod 28 projects from one end of the valve and has on its lower end a valve member 37. A further valve member 38 is also provided. In operation, whilst the valve is out of action, the outlet 26 to an air spring bellows is closed by a valve head 43 and the valve member 37 is held by a spring 41 against the inlet end of a bore 33. When levelling of the vehicle is required high pressure air is supplied to the valve through the ports 23, 24, thus forcing the valve member 37 up until the rod 28 comes into contact with an abutment which is connected with the sprung part of the vehicle. Simultaneously the valve member 38 is moved to a position in which a conduit 55 connects the bore 33 with the bellows supply port 26. Air will now enter or leave the bellows depending upon the position of the abutment connected to the sprung portion of the vehicle. A modification is described, Fig. 3, (not shown), in which the sliding valve member corresponding to valve member 38 has three lands and two outlet ports are provided. Thus, air can be supplied to two bellows. In a further embodiment one bore only is provided' in the. valve body and a single spool valve 71, Fig. 4, having two lands 72, 73 controls a pressure inlet port 75 a bellows supply port 26 and an exhaust port 25. A further bellows supply port may be provided diametrically opposite-to the supply port, 26. If the levelling valve is to be used whilst the vehicle is in motion, damping means may be interposed between the rod 28 and the sprung portion of the vehicle.