Patent GB-1314034-A (GB)
Title: Self levelling lamps for vehicles
IPC: B60Q1/10
Filed: 1969-07-01
Abstract: 1314034 Controlling vehicle headlamps MARTIN WARD (DEVELOPMENTS) Ltd 26 June 1970 [1 July 1969 22 April 1970] 33293/69 and 19361/70 Heading F4R [Also in Division F2] In a vehicle lamp levelling system having a pair of vehicle body level signal generating mechanisms associated with the front and rear suspensions, respectively, the signals are applied to a signal mixer unit, Fig. 2, comprising a housing 27 containing two springs 32, 33, one end of each spring being connected to an output signal transmission member and the other ends of the springs being connected to the means for transmitting the respective input-signals. The spring 32, which is in compression, acts between a pair of pistons 28, 29, the first of which carries a pair of diametrically opposed pegs 30 abutting the bifurcated upper end 19a of a lever 19 secured to the front anti-roll bar 20 and the second of which constitutes the output signal transmission member and carries a lug 35 engaging a rocking arm 15 connected to the lamps. The spring 33, which is in tension, is stretched between the piston 29 and the end of a cable 18 which passes over a pulley (not shown) and is fastened to the rear axle differential unit. In an alternative embodiment (Fig. 8, not shown) two compression springs (132, 133) are employed and the output signal transmission member is a slide disc (129) disposed between the springs. The rocking arm 15 is connected by a tension spring 22, Fig. 1, to a tongue 21 projecting from a pivoted crossmember 11 extending between the lamps 1 on cpposide sides of the vehicle, each lamp being tilted by a respective tongue 10 which also projects from the cross-member and abuts a screw 7 held by nuts 8, 9 in a bracket 6 on the lamp. The screw is adjustable both in the cirection of its length and along a slot in the bracket so that different lamps may be given different response ratios. Lamp movements are damped by a unit 5 comprising a spring-loaded plunger 25 movable in a tube 23 which contains hydraulic fluid and is sealed by a bellows 26. In a modification (Fig. 3, not shown) a single damper unit (44) acts on the cross-member 11 and the spring 22 and tongue 21 are replaced by a leaf spring (41). The system may be further modified to cause the lamps to dip upon deflection of the steering, such deflection being produced by deflection of the cable 18. Means are described (Fig. 11, not shown) whereby a push-pull button (198) on the dashboard causes tilting of the lamps, such tilting being additional to the tilting produced by the lamp levelling system. Several distinct settings for the push-button, corresponding to "fog", "dipped beam", "main beam" and "long beam" illumination, may be provided. In an alternative form of connection between the signal mixer unit and the cross-member 220<SP>1</SP>, Fig. 14, the output signal from the unit is transmitted by a strut 223 to an arm 226<SP>1</SP> having a threaded portion 231 engaging an internally threaded sleeve 230 tangentially secured to a sleeve 229 rotatable on the crossmember. The angular position of the sleeve 229 is adjusted by a screw 234 acting between tabs 232, 233 projecting from the cross-member and sleeve, respectively, and urged apart by a strong compression spring 236. An alternative form of damper for use in any of the described systems is shown in Fig. 13 and comprises a bipartite piston 209 movable in an oil-filled cylinder 206. The piston comprises a plate 211 and a cup 210 urged apart on the piston-rod by a compression spring 214 and provided with non-aligned passages 215, 216 respectively. Rapid movements of the piston cause the plate and cup to approach one another and thereby increase the damping effect. Pivotal mountings  for the lamps are also described but form the subject-matter of Specification 1,314,035.