GB1471652A - Control arrangement for vehcile headlamps - Google Patents

Abstract

1471652 Control of vehicle headlamps by DC motors LUCAS ELECTRICAL Ltd 18 July 1974 [10 Aug 1973] 37914/73 Headings H2H and H2J The headlamps (not shown) of a vehicle are moved between an extended operative position and a retracted inoperative position when contacts 17, 18 of switch units 10, 11 are operated to continuously energize or de-energize the main beam or dipped filaments 20, 22 and cause energization of motors 13, 14 driving the lamps, the unit 11 having a further contact 24 (ganged to contact 18) operable to briefly energize the filaments 20 and cause normal extension of the headlamps, retraction being delayed, when the contact 24 de-energizes the filaments 20, due to the time taken by a heat sensitive switch to restore to its normal condition, which switch is controlled by the contact 24 and controls the motor supply circuits. In Fig. 1 operation of contact 17 to its lower positions continuously energizes the filaments 20 or 22 according to the position of switch 18 and energizes the coil 33 of a relay 12 whose contact 34 changes over to connect a supply T to motors 13, 14 through contact 36, diodes 47, 50 and the contacts 45, 51 and 48, 52 of respective changeover switches 13a, 14a. At or towards the end of the motor (lamp) movement, the contacts 51, 52 are changed over by the motors to switch them off and engage contacts 39, 51 and 42, 52. The latter pairs of contacts complete energizing circuits for the motors to retract the lamps when contact 17 is restored to its upper position, coil 33 is de-energized- and contact 34 changes over to engage contact 35 and connect supply T to diodes 41, 44 and the aforementioned contact pairs. Subsequent motor movement again changes over the contacts 51, 52. Depression of contact 24 to energize filaments 20 also energizes a heat extensible strip 15 through members 26, 27, 28, 18 and 22 (which are not illuminated) and energizes the relay coil 33 to extend the headlamps in the aforedescribed manner. Normally-closed contacts 16 are opened by energization of the strip 15 and reclose with a time delay when the contact 24 is opened to allow the strip 15 to cool, the lamps thus remaining extended until contacts 16 close to complete the motor supply circuits. Further operations of the contact 24 are thus possible before the lamps are retracted. Malfunction of the switch 15, 16 to cause contacts 16 to be permanently closed or open will respectively produce immediate retraction of the lamps or prevent retraction after extension. The modification shown in Fig. 2 uses a heat sensitive switch 115, 116 whose contacts are normally open and control the coils 133a, 133b of relays 112a, 112b controlling the motors 113, 114 through changeover switches 113a, 114a. Closure of contact 124 energizes the relay coils from supply S through members 126, 153 to extend the headlamps and also energizes strip 115 to close contacts 116. When contact 124 is opened, contacts 116 remain closed for a predetermined time to energize the relay coils from a supply R and so prevent immediate retraction of the lamps.