GB875692A - An improved levelling valve for vehicles with pneumatic or hydraulic suspension - Google Patents

Abstract

875,692. Levelling vehicle suspensions. DUNLOP RUBBER CO. Ltd. May 2, 1960 [May 6, 1959], No. 15464/59. Class 108(2). A levelling valve operating automatically to admit or exhaust fluid from a suspension system in response to changes of the load on a vehicle has a piston 34 movable in either direction from a neutral position in a liquidfilled cylinder 13, a passage from one end of the cylinder to the other for restricted fluid flow and means actuated by the piston 34 to operate inlet 25 and exhaust 26 valves, the said valves being operated only after the piston has travelled a predetermined distance from its neutral position. A lever actuated by load changes turns a shaft 38 causing a forked lever 39 to press against one or other of washers 41 or 42. Washers 41 and 45 are fixed on either end of a rod 43 movable axially inside the piston between limits set by stops 46 and the washer 42 is slidable on the rod 43 against a spring 44. In consequence of this and of the restricted fluid flow, the piston moves only slowly and does not move at all for transient displacement of the lever 39. An actuating lever 31 engages with'clearance in a notch 33 in the piston and extends through, and is pivoted about, an elastic seal 32 situated between the cylinder 13 and an air-valve chamber 14. The outer end of lever 31 protrudes between two grooved pins 30 which operate the inlet and exhaust valves 25 and 26. The valves 25 and 26 comprise fourpronged thimbles seated on springs 22 and 27 and carrying rubber pads 24 and 28 which can seal a delivery conduit 17 from the inlet pipe 15 or from an exhaust outlet 17 respectively. Another thimble 18 and pad 23 on the spring 22 serve as a non-return valve.