Patent GB-570183-A (GB)
Title: Improvements in or relating to suspension spring devices for road and other vehicles
IPC: B60G17/02
Filed: 1943-06-22
Abstract: 570,183. Vehicle spring suspensions. BALLAMY, L. M., and SHEEPSHANKS, R. H. June 22, 1943, No. 10077. [Class 108 (ii)] Relates to a vehicle suspension system having a wheel rotatably mounted on the free end of a substantially horizontal arm which is pivotally connected at its other end to the. vehicle body or equivalent. According to the invention,' springing means are provided between the vehicle body and the arm to urge the arm downwardly, the means comprising a main spring, an auxiliary spring connected in series with the main spring so that the static load of the vehicle is transmitted through one to the other, and a hydraulic dashpot device which is operatively connected in parallel with the auxiliary spring and thereby protects the auxiliary spring from rapid changes in load of substantial magnitude. As shown in Fig. 1, the wheel-carrying arm 11 pivoted in bearings 12, 13 on the vehicle body or chassis, has a bevel gear 14 meshing with a gear 15 on a torsion bar 16 constituting the main spring, the adjacent end of the bar being rotatably mounted in a fixed bearing 17 and its opposite end being splined in a collar 18 having a radially-projecting arm 19. One end 31 of a second torsion bar 32 constituting the auxiliary spring is also splined in the collar 18, its opposite end 34 being secured to the vehicle body or chassis. To the free end of the arm 19 is pivoted the piston-rod 21, Fig. 2, of the dashpot 22, the cylinder 23 of which is pivoted at 25 to the vehicle body, while the piston 27 is formed with a constricted passage 28 to allow only slow flow of fluid from one side of the piston to the other. In operation, slow or gentle vertical movements of the wheel 10 are transmitted through the gears 14, 15 to the relatively stiff bar 16 and thence to the bar 32, the dashpot 22 readily permitting these movements. Violent shocks on the wheel, however, are absorbed by the bar 16, since the dashpot prevents their transmission to the bar 32. In a modification, the main spring is formed by a torsion tube which surrounds the auxiliary torsion bar 32. A wheel mounting for a motor or other cycle is shown in Fig. 4, the wheel axle 42 being secured at each end to an arm 43 or 43a movable about an axis 45 and carrying a bevel gear 48 or 48a meshing with a gear 47 or 47a at the lower end of a torsion bar 46 or 46a, the upper end of which is rotatably mounted'in a bearing 51 in the fork structure. Arms 52, 52a, Fig. 5, urged apart by a spring 53, extend forwardly from the upper ends of the torsion bars 46, 46a and a dashpot 22 is also connected between the arms. Slight shocks on the wheel 41, tending to twist the torsion rods 46, 46a in opposite directions and thereby moving the arms to compress the auxiliary spring 53, are permitted by the dashpot, while heavy shocks are taken by the torsion bars, the dashpot preventing transmission to the spring 53. Fig. 6 shows another construction in which the load of a vehicle is transmitted to a half-axle 60 through main and auxiliary springs 62, 63 separated by cups 64, 65 which enclose both the spring 63 and a dashpot 22, the piston-rod 21 of the dashpot being pivoted at 68 to the half-axle. In a modification, the main spring 62 is replaced by a leaf spring. In a further construction, Fig. 8, a wheel axle 69 is connected by a main coiled spring 70 to one end of a lever 71 pivoted at 72 to the vehicle body, an auxiliary spring 75, having a rate equal to the main spring, being interposed between the body and the lever 71 at a point midway along the length of the lever. A dashpot 22 connects the free end of the lever with the vehicle body. The invention may be applied to systems embodying main and/or auxiliary springs comprising compressed gas contained in a variable volume chamber. More than two spring elements may be coupled together to operate in series, each junction being connected with the vehicle chassis &c. by a dashpot. The dashpots may be constructed so as to be responsive to shocks of successively increasing magnitudes. Specification 562,686, [Group XXXI], is referred to in the Provisional Specification which also mentions a dashpot of the radial vane type.