GB1492800A - Adjusting device for regulating the elevation of vehicle headlamps - Google Patents

Abstract

1492800 Regulating vehicle headlamps ROBERT BOSCH GmbH 2 Oot 1974 [3 Oct 1973] 42683/74 Heading, F4R [Also in Division G3] The light-range of vehicle headlamps 24, Fig. 1, is automatically adjusted in response to relative movement of the vehicle chassis with respect to its axles by a servomotor 50 connected to the lamps and having valves operated in response to movement of a piston 43 which compares pressure signals from modulators 9, 10 on the front and rear axles. Positive pressure is supplied to the modulators from a source 3 and valves 62, 63 and 66, 67 are closed when equal signals are applied by the modulators to opposite sides of the piston 43, the servomotor being at rest. When axle movement causes a pressure difference and upward movement of the piston 43, and valve 66, 67 opens and air flows from chamber 39 into a chamber 53 to raise the servomotor 50 and pivot the headlamps through a pivoted link 77 and a spring-loaded cable 22. Downward movement of the piston 43 in response to a reversal of the pressure difference opens the valve 62, 63 to allow air to escape from the chamber 53 to atmosphere through a filter 90 and a port 91. The space (153) Fig. 3 (not shown) above the piston (150) may be at positive pressure and the space (154) beneath it connected to atmosphere through a filter (190), the valves (165, 167 and 166, 168) controlling communication between the spaces and between the space (153) and the source of positive pressure having a modified constuction. A construction similar to that of Fig. 3 may be vacuum operated, but with the space above the servomotor (250) Fig. 5 (not shown) connected to atmosphere through a filter so that if either of the lines between the modulators and the piston (238) breaks the headlamps pivot downwardly. A similar result is produced with positive pressure operation by providing a spring-loaded valve 142, Fig. 4, which is normally held open by the pressure in line 15; failure of this pressure causes the valve to connect the space 153 above the servomotor to atmosphere through passages 192, 196 and pivot the headlamps downwardly. Fig. 6 illustrates a vacuum operated embodiment in which the piston 338 responsive to pressure signals from the modulator is firmly secured to a tube 358 arranged to separate from a valve disc 365 on upward movement of the piston and to separate the disc from a bore 356 on downward movement of the piston. The valve disc may be arranged to co-operate with a seat (467) Fig. 7 (not shown) in the servomotor piston (450). Reference has been directed by the Comptroller to Specification 1,333,509.