Patent GB-515969-A (GB)
Title: Improvements in and relating to springing arrangements for vehicles
IPC: B60G15/06
Filed: 1938-06-17
Abstract: 515,969. Vehicle spring-suspensions; shock absorbers. PORSCHE, F. June 17, 1938, No. 18028. Convention date, July 21, 1937. [Classes 108 (ii) and 108 (iii)] In a vehicle spring-suspension in which the sprung' parts are automatically returned to their middle posifion when the load on the vehicle is varied, a fluid pressure operated return mechanism acts on the unsprung parts through an auxiliary spring. As shown, the axle 1, Fig. 5, carries an arm 2 connected by a rod 3 to a lever 4, 6 fulcrummed at 5 on the chassis. The arm 6 is connected to the auxiliary spring 7, 7<1> which abuts against the piston 8 of the return mechanism. The cylinder 9 is connected via a pipe 10, valve 12 and pipe 14 with a pressure container 16, and via a pipe 11, valve 13 and pipe 15 with a fluid reservoir 17. The container 16 and reservoir 17 .are interconnected by a pipe 88 fitted with a one way valve 39. The lever arms 4, 6 are rigid with an arm 23 which operates the double-ended piston 22 of a shockabsorber, the pressure chambers 24, 25, of which are connected by pipes 26, 27, fitted with adjustable throttle valves 28, 29, to the container 16, and by pipes 32, 33, fitted with non-return valves 30, 31, with the reservoir 17. The piston 22 carries an arm 19 connected to a member 20 slidable, against the action of springs 21, 21', in a hollow double-ended piston 18, movement of which operates the valves 12, 13. The piston works in a fluid filled cylinder, the ends 34, 35, of which are connected by a pipe 36 provided with an adjustable throttle valve 37. In a constructional example, Fig. 4, the return mechanism, shock-absorber &c. are contained in a casing 40 secured at 41 to the chassis. The auxiliary spring consists of the torsion bars 7, 7<1> and the container 16 is located in the lower part of the casing and the reservoir 17 in the upper part. The valves 12, 13 are spring loaded mushroom valves. Thus for a given load on the vehicles, when the suspension is subjected to shocks, the lever 4, 6, is caused to oscillate. If, for example, the piston 22 is moved to the left, the liquid in the space 24 is forced through the throttle 28 to the container 16. Due to the throttle 29 the reduction of pressure in the space 25 is not compensated for sufficiently rapidly so that the valve 31 opens and liquid flows from the reservoir 17. When the piston moves back liquid is forced to the container from the space 25 and the container is thus kept permanently under pressure by the shock-absorber. Dangerous excessive pressures are avoided by the valve 39. Since the operation of the piston 18 is not positive, the throttle 37 may be adjusted so that the valves 12, 13 are not operated. If the permanent load of the vehicle is altered, e.g., increased, the lever 4, 6 is rotated in a clockwise direction and the piston 22 moves to the left carrying with it the piston 18 which will lag due to the spring 21 and throttle 37. The valve 12 is thus opened and fluid under pressure will flow from the container 16 to the cylinder 9 thus increasing the stress of the auxiliary spring 7 7<1> The lever 4, 6 will then be rotated in an anti-clockwise direction until the pistons 21 and 18 have reached their middle positions and the valve 12 is again closed. If the vehicle load is decreased, the valve 13 is opened and liquid flows from the cylinder 9 to the reservoir '17 thus reducing the stress on the auxiliary spring. The spring 7, 7<1>, may be any type of metallic spring or a rubber spring stressed in any desired manner. The fluid used in the return mechanism and shock absorber, may be liquid or gaseous and in the latter case is preferably air so that the reservoir 17 may be dispensed with. The fluid controlling the piston 18 is air or the fluid used in the return mechanism and shockabsorber.