Patent GB-974702-A (GB)
Title: Improvements in vehicle suspension systems
Inventor: POWELL GEORGE BERTRAM
IPC: B60G17/044
Filed: 1960-03-18
Abstract: 974,702. Vehicle suspension system; levelling. GIRLING Ltd. March 20, 1961 [March 18, 1960], No. 9594/60. Heading F2S. A wheel suspension unit for vehicles comprises a piston and cylinder assembly 10, 12 located within a cylindrical housing 13 the annular space between which and the cylinder 12 is divided by two longitudinal partitions, not shown, into a part annular energy storage chamber 16, which communicates with the cylinder through a Venturi 25, and a part annular reservoir chamber 18 which is connected with the throat of the Venturi by a passage 19, controlled by a one-way valve 21 in a plug 22, and an aligned passage 24 in the Venturi member. On relative movement between the piston 10 and the cylinder 12, due to suspension movements of the vehicle in motion, the flow of liquid through the Venturi causes liquid to be drawn into the cylinder 12. The Venturi 25 is mounted in a plug 26 which closes the lower end of the cylinder 12 and has passages 27 controlled by oppositely-acting valves 28 for damping the flow of liquid between the cylinder 12 and the chamber 16. Closed flexible bags 29, 33, with nozzles for filling with gas, e.g. nitrogen, are spaced by springs 32 in the chambers 16, 18 respectively. The reservoir 18 also communicates with the cylinder 12 through a levelling port 23 which is uncovered when the piston 10 is approaching its maximum extension. Liquid drawn from the reservoir through the ducts 19, 24 into the cylinder 12 increases the total volume of liquid in the latter to extend the unit and increase the ground clearance of the vehicle, extension continuing until the piston uncovers the levelling port 23 so that liquid can return to the reservoir chamber 16. In order to increase the delivery of liquid into the cylinder 12 when the unit is considerably compressed a metering pin 34, of varying cross-sections and attached to the piston 10, co-operates with the Venturi throat, the pin 34 being received within a hollow stud 15 for connecting the housing 13 to a part of the suspension. In an alternative method of achieving the latter result an annular space 36 provided around the Venturi 37, Fig. 3, has a by-pass 38 which is obturated when a cylindrical extension 42 of the piston rod enters the annular space 36. In a further modification of this kind, Fig. 4, the Venturi is provided with an upward, convex extension 43 which co-operates with the skirt 42 so that access for liquid to the by-pass is closed progressively. In a modification of the unit, Fig. 2, the cylinder 46 is formed by the inner wall of a hollow cylindrical reservoir chamber 47, the storage chamber 51 being formed by an annular space between the outer wall of the reservoir chamber 47 and the housing 49 and annular gas bags 52, 53 being accommodated respectively in the chambers 51, 47. The hollow piston and rod 54, 55 engage over an axial sleeve 56 which extends upwardly from the Venturi 57, and a passage 58 in the piston 54 controlled by a one-way valve 59 provides communication between the cylinder spaces at both sides of the piston 54. On return strokes the valve closes so that all the liquid must return through the Venturi and liquid is drawn from the reservoir so that pumping takes place only on the rebound strokes. The gas springs such as 52, 53 may be replaced by spaces containing gas at high pressure which are separated by freely movable pistons from the respective liquid spaces.