Patent GB-818023-A (GB)
Title: Improvements in and relating to pressure regulator for a suspension for a vehicle orother structure comprising dampers containing both a liquid and a compressed gas
IPC: B60G17/04
Filed: 1957-04-15
Abstract: 818,023. Road-vehicle spring-suspensions. SOC. D'ETUDES ET D'APPLICATIONS INDUSTRIELLE COMMERCIALES ET IMMOBILIERES, INTER-TECHNIQUE. April 15, 1957 [April 18, 1956], No. 12189/57. Class 108(2) In a vehicle suspension system provided with two combined hydraulic and pneumatic dampers connected by a pressure regulator to a source of air or gas under pressure, the regulator comprises a balancer which acts on a discharge valve and a valve connected with the source, a connection having a resilient yieldable member between the balancer and the mid-point of the unsprung part, and two dashpots, to damp these oscillations strongly, each having a mobile element urged by a return spring against an abutment, and a device which eliminates the dashpot action during the return of the element. As shown the suspension comprises adjacent each rear wheel a conventional spring 1 and a telescopic hydraulic and pneumatic damper 2 the regulator C, which serves to introduce or withdraw gas to control the pressure of the gas in the ends 7 of the dampers, comprises a chamber 9 connected at 10, 11, 12 to the dampers and at 13 has a compressed air tank 14, and inlet valve 16, check valve 18, and discharge valve 21 which are normally closed by springs 17, 19, 22 respectively. The balancer, pivoted at 24, comprises three arms 23, 25, 26, the latter being connected by a spring 27 to a bell-crank 28 linked at 30 to the rear axle casing, so that when the body A occupies its normal position there is a clearance j between the stems of valves 16, 21 and arms 23, 25. The oscillations of the balancer are damped by dash-pots D, E. The pistons 35 of the dashpots, which are urged upwardly to contact abutments 37 by weak springs 36, each has a small orifice 39 and a plurality of large apertures 40 which are closed by a valve member 41 urged against the piston by a spring 42. Thus when the piston moves downwardly the movement is highly damped since valve 41 closes apertures 40 and oil can escape through orifice 39 only, but return movement is relatively free since the oil displaces valve 41 downwardly. When the pistons engage abutments 37 piston rods 44d, 44e engage arms 23, 25. Fig. 1 shows the body A at rest at a normal altitude Zo. If now the load is decreased the body A rises; lever 28 turns counterclockwise, the balancer pivots clockwise, and arm 23 presses on rod 44d. If the change is small this pressure does not overcome spring 36, and this body remains thus slightly displaced. If the load continues to decrease the piston of dashpot D is urged downwardly, braked by flow through orifice 39, until arm 25 engages the stem of valve 21. If no further change occurs the body remains in this slightly displaced position. If the load decreases further, however, arm 25 overcomes spring 22 and the pressure of gas in chamber 9, spring 27 stretching, and raises valve 21 so that gas escapes from chamber 9. Spring 27 returns to normal, the pressure in chamber 9 and ends 7 drops and the body A descends. Spring 27 acts as a rigid link, the balancer turns counterclockwise and valve 21 descends and closes when the altitude of the body is only slightly more than Zo. Movement of the body then ceases. The descent of body A is slow since the gas outlet is small. The dimensions of the pistons of dashpots D, E and of orifices 39 are such that the maximum movement of the pistons as a result of oscillation of the body on its suspension is less than the clearance j. Similarly when the axle rebounds relatively to the ground the amplitude of oscillation of the balancer is insufficient to operate valves 16 or 21. The spring 27 and bell-crank 28 may be replaced by a rod journalled in a bearing on the body, having a portion bent through 90 degrees, and a portion under tension. The regulator may adjust the pressure by withdrawing or introducing the liquid instead of the gas.