Patent GB-636266-A (GB)
Title: Improvements in suspension systems for vehicles
IPC: B60G11/18
Filed: 1947-09-02
Abstract: 636,266. Spring suspensions; torsion springs. ELVIDGE, H. Sept. 2, 1947, No. 24252. [Classes 108 (ii) and 108 (iii)] A vehicle suspension system comprises primary and secondary resilient members in the form of two torsionally-resilient bars connected together end-to-end, the secondary resilient member being stiffer than the primary resilient member which is rendered ineffective when the vehicle is laden beyond a certain amount whereupon the secondary resilient member takes all the load. In a preferred arrangement which is applicable to the vehicle suspension described in Specification 442,977 for an independent wheel suspension, the primary and secondary springs comprise integrally-connected torsion bar members 1 and 2 respectively, extending longitudinally of the vehicle. The free end of the secondary member 2 is splined to one end of a torque tube 6 which is rotatably mounted in a bracket 7 secured to a vehicle frame member 5. The other end of the tube 6 is pinned to a sleeve 8, which is rotatably supported in a bracket 4 secured to the frame member 5 and which carries a pair of arms 10 which are connected at their outer ends to a road-wheel. The interconnected ends 3 of the primary and secondary members 1 and 2 are splined to one end of a torque tube 13 which surrounds the primary member 1 and which at its other end is rotatably supported on a portion 14 at the free end of the primary member 1. The bracket 4 and a sleeve 15 secured to the tube 13 are each provided with a series of radially-projecting teeth 16 which together form a dog-clutch device. The free end of the primary member 1 carries an integral extension 1<SP>1</SP> which is splined to a disc 18, which may be adjustably secured to a corresponding ring 19, formed integral with the bracket 4, by rotation of the primary member. The latter is rotated by means of an internally-splined spanner applied to the extension 1<SP>1</SP>. In operation, when the vehicle is unladen or lightly laden the teeth 16, 17 are not in contact and relative vertical movement of the vehicle wheel and frame is transmitted through the arms 10, tube 8 and secondary member 2 to that end of primary member 1 anchored to the frame through the disc 18 and ring 19, without any substantial twisting of the secondary member 2. Increased loading of the vehicle causes further rotation of the tube 6 and the engagement of the teeth 16 and 17, whereby further twisting of the primary member 1 is prevented and resistance to relative vertical movement of the vehicle wheel and frame is provided solely by the secondary member 2. Overstressing of the secondary member 2 under excessive vehicle loading is prevented by means of a dogclutch device, comprising teeth 23 on the sleeve 8 which engage with similar teeth on the bracket 4. A vibration damper comprising rings 25 of friction material clamped between flanges 26, 28 at the outer end of the tube 6 restrains undue rotary oscillation and vertical vibration of the arms 10 irrespective of vehicle loading. In an alternative arrangement according to the Provisional Specification, the wheelcarrying arm is rigid with the inner tube and the frame. The secondary spring is thus inoperative when the vehicle is unladen and under load the two springs act in parallel.