GB2358297A - Reducing brightness of dipped headlight on activation of turn indicator - Google Patents

Abstract

The vehicle directional indicator circuit is designed to allow reduced brightness of a vehicle's dipped headlamp (left or right) when signalling a turn to the left or right. The unaffected headlamp will remain bright and the circuit energised only when a vehicle's indicators are used in conjunction with the headlights being switched on. The main beam headlamps are not affected. The circuit provides improved visibility of indicator light to oncoming vehicles at night.

Description

2358297 VEHICLE DIRECTIONAL INDICATORS [Technical field] This invention

relates to an improved circuit diagram for directional indicators which are a basic requirement for all 'road- using' vehicles.

[Background] In 'The Casualty Report' (Road Accidents Great Britain 1998), it is shown that more than 63,000 vehicles were involved in accidents, either in the process of turning right or turning left. Furthermore, there were more than 387,000 accidents in all known manoeuvres. The report, unfortunately, does not indicate how many accidents occurred in normal daylight hours or during night time driving but nevertheless exposes a weakness in general driving care and perhaps a need for improvement to vehicle lighting design. This invention considers the latter point.

Modem vehicle indicator wiring systems comprise a flasher unit and directional indicator switch. The flasher unit is designed to meet international standards and has to provide audible and visual means to signal lamp failure. The most common type of flasher unit today is electronically operated and when an indicator lamp fails it flashes at approximately twice its normal rate. The indicator switch is a two-way switch with a central off position. Its purpose is to energise the indicator lamps at the front, side and rear of the vehicle in order to signal a turning or overtaking decision by the vehicle driver. Some vehicle drivers use the hazard facility associated with this switch to warn others of possible danger. For example, if they are badly parked and 'off-loading' or sometimes to warn other drivers to reduce their speed if the road ahead suddenly becomes blocked with stationary traffic.

- ------------ 2 The trend today in vehicle headlight design, particularly motorcars, is to incorporate the front directional indicator and headlamp in one module and also to design flie headlamps to a much higher degree of brightness. In the latter case, during night, driving, the new higher luminous intensity headlamp bulbs are giving rise to concern by making it even more difficult to observe the brightness of the indicata. lights when a vehicle is signalling to turn left or right or signalling to overtake another vehicle. This problem is aggravated in wet driving conditions and when flie signalling vehicle is leading a line of other traffic. The inventor feels that vehicle manufacturers have overlooked the danger caus by headlamp 'glare'- the phenomenon of seeing a bright object against a da ' background. This condition results in the difficulty to see contrast and detail wi if prolonged, as in night driving, leads to tiredness, lack of concentration and tb possibility of a road accident.

[Essential Technical Features] The modified vehicle directional indicator circul is shown in Figure 1.0. It shows two independent relay circuits fed from Mic directional indicator switch, i.e.one for each indicator system. It is only when die indicator switch is activated that the left or right relay coil becomes energise 1 1 When this occurs, the normally- open contact closes and inserts a 'drop' resistor i series with the dipped headlamp bulb which reduces its brightness. With eati relay working independently, one headlamp will always be operating at fl brightness which will provide sufficient lighting for a driver to see when in Ox process of turning or overtaking. As soon as the indicator switch is turned off dx affected dipped headlight reverts to flill brightness. It will be seen from Figure 1.0 that when the directional indicators are not activate the dipped beam circuit operates through a normally closed contact in the relay. 1 fected by the modified circuit should be noted that the main bean circuit is not af [Conclusion] During night driving and when any of the manoeuvres describl, .c above are initiated, the modified indicator circuit shown in Figure 1. 0 will proviffi greater opportunity for an 'oncoming' driver to clearly see the intention of. 1 approaching vehicle. The inventor feels that the circuit needs to be implemented l all vehicle manufacturers, preferably through government legislation.

Claims (4)

Claims

1 A modified circuit diagram for directional indicators designed to decrease the brightness of dipped headlamps of all vehicles during night time driving.

2 A modified circuit diagram for directional indicators claimed in Claim 1 designed to avoid 'disability glare' and allow all vehicle indicator fights to be clearly seen by oncoming drivers'.

3 A modified circuit diagram for directional indicators claimed in Claim 1 designed to be functional only when a road vehicle is in the process of turning left or right or during the process of overtaking.

4 A modified circuit diagram for vehicle directional indicators claimed in Claim 1, 2 and 3 as shown in Fig 1.0 in which the wiring to each dipped headlamp bulb operates through an independent relay. When a particular relay coil is energised a normally open contact closes, inserting a 'drop resistor' in series with the dipped headlamp bulb; this reduces the bulb's rated voltage and its luminous output decreases. A normally closed contact in the relay serves the purpose of allowing the unaffected headlamp to continue giving fifil brightness.