Patent GB-632180-A (GB)
Title: Vehicle suspension means
IPC: B60G17/015
Filed: 1946-11-21
Abstract: 632,180. Spring-suspensions. LLOYD, W. Nov. 21, 1946, No. 34557. [Classes 108 (ii) and 108 (iii)] In a vehicle-suspension of the hydro-pneumatic type in which each wheel is associated with a piston operating in a cylinder carried by the chassis, each cylinder is connected to the underside of a corresponding twodiameter piston operating in a two-diameter cylinder and all the twodiameter cylinders open into a common pressure chamber. Spring-suspensions.-The wheels of a vehicle are independently suspended, each axle being carried by a pivoted arm 11, Fig. 4, supported by a piston E slidable in a cylinder F containing liquid under pressure. The cylinders F<SP>1</SP> ... F<SP>4</SP>, Fig. 1, for the four wheels are individuallyconnected by pipes G<SP>1</SP> ... G<SP>4</SP> to inner cylinders J<SP>1</SP> ... J<SP>4</SP>, within each of which fluid pressure is maintained by a two-diameter piston H<SP>1</SP> . . . H', of which the part of small diameter is received in the inner cylinder while the part of large diameter is slidable in an outer cylinder, all the pistons being urged downwardly by air or gas under pressure in a common chamber K. To absorb shocks, means are provided to relieve a sudden rise in pressure in the chamber K and to make good a sudden decrease in pressure on rebound. For this purpose, the waisted spring-balanced sleeve Z<SP>1</SP> of a valve is subjected at its right-hand end to the pressure in the chamber K and at its left-hand end to the pressure in a chamber Z, connected to the chamber K through a flow-restricting valve Z<SP>3</SP>. Upon a sudden rise in pressure in the chamber K, the sleeve Z<SP>1</SP> moves to the left to permit air to escape from the chamber through a port Z<SP>7</SP> and pipe Z<SP>5</SP> to a low-pressure sump K<SP>1</SP>. Alternatively, upon a sudden lowering of pressure in the chamber K, the sleeve moves to the right and air is admitted to the chamber from a highpressure chamber P<SP>2</SP> through a pipe Z<SP>6</SP> and the port Z'. Air is supplied to the high-pressure chamber P<SP>2</SP> from the sump K<SP>1</SP> through a non- return valve P<SP>1</SP> by a pump P, the pressure in the chamber being maintained approximately constant by a relief valve P3. Adjusting height of body from ground.-The mean heights of the pistons H<SP>1</SP> ... H<SP>4</SP> in their cylinders, and hence the mean height of the vehicle body from the ground, is automatically adjusted by varying the pressure in the chamber K. For this purpose, a tubular valve O is connected to the mid-point of a link N pivoted at its ends to the mid-points M<SP>1</SP>, M<SP>2</SP> of two links L<SP>1</SP>, L<SP>2</SP>, which couple each pair of adjacent pistons H<SP>1</SP>... H<SP>4</SP>. The valve O is thus maintained at a height which corresponds with the mean level of the pistons. The valve is slidable in a casing O<SP>1</SP>, in communication by a pipe P<SP>4</SP> with the high-pressure chamber P<SP>2</SP>, and extends into the sump K<SP>1</SP>. Upper and lower ports O<SP>2</SP>, O<SP>4</SP> are provided in the wall of the valve, of which the upper O<SP>2</SP> is in constant communication with the chamber K, whereas the lower is normally sealed by the lower end of the casing O<SP>1</SP>, the arrangement being such that upward movement of the valve admits air under pressure to the chamber K, while downward movement permits air to flow from the chamber to the sump. The ports in the valve O are small in comparison with those in the shockabsorber valve to enable the latter to have an over-riding effect. Preventing lateral cant.-To cause the body to tilt relatively to the wheels in the opposite sense to the slope of the surface on which the wheels rest, means are provided to adjust the pressure in the outer cylinders J<SP>1</SP> ... J<SP>4</SP> beneath those parts of the pistons H<SP>1</SP> ... H<SP>4</SP> which are of larger diameter. These means comprise two electrically-operated valves Q<SP>1</SP>, Q<SP>2</SP>, each associated with a pair of cylinders J<SP>1</SP>, J<SP>2</SP> or J<SP>3</SP>, J<SP>4</SP> related to diametrically-opposed wheels. Each valve comprises a waisted sleeve spring-urged to central neutral position, from which it may be moved to left or right by the energization of solenoids A(C) or B(D). On movement of a sleeve to the left, the right-hand cylinder of the pair associated with the valve is connected to the sump K<SP>1</SP> through pipes R<SP>3</SP>, S<SP>3</SP> or R<SP>4</SP>, S<SP>4</SP>, and immediately thereafter, the left-hand cylinder is connected to the high-pressure chamber P<SP>2</SP> through pipe R<SP>2</SP> or R<SP>1</SP> and pipe P<SP>4</SP>. The energization of the solenoids is controlled by a quadrantal series of contacts a ... d encircling a pendulum bob e which may be caused by the cant of the vehicle, or by inertia or centrifugal forces, to move into engagement with one of the contacts or any pair of adjacent contacts. The pendulum bob may be replaced by mercury in a shallow cup, the quadrantal contacts being disposed just above the surface of the mercury. To limit the amount of correction, when the vehicle traverses a steep slope, the point of suspension of the pendulum is moved in a direction opposite to that of the tilt by a pair of quadrants Y<SP>1</SP>, Y<SP>2</SP> connected through dash-pots X<SP>1</SP>, X<SP>2</SP>, lost-motion devices U<SP>1</SP>, U<SP>2</SP> and links, to arms M<SP>3</SP>, M<SP>4</SP> rigid with the links L<SP>1</SP>, L<SP>2</SP>.