FOCUSING HEADLIGHTS

Evening Star, Issue 22087, 22 July 1935, Page 13

FOCUSING HEADLIGHTS

METHODS OF ADJUSTMENT Do you enjoy driving at night? If you do not, and if you have normal eyesight, then the probability is that your headlamps are at fault. A good driving light makes all the difference ■ between a pleasure and a penance, and there are many experienced drivers who, in these days of congested traffic in towns and busy, main roads, actually prefer night driving. . . To obtain a good driving light it is essential (I) for the lighting system itself to be: in good order, and (2) for the light to he thrown in the required direction. As regards the lighting system, the battery should be well 'charged, the wiring should bo in good ordqr, and the bulbs should not be past their prime. Also the reflectors and front glasses should: be clean.

BATTERY, BULBS, AND WIRING. If the battery is. not in good condition or the wiring is defective then the bulbs may not receive tbeir proper voltage, and consequently will not produce the amount of light or candle T power that they should. Again, if the bulbs are too old, if there is a marked discolouration on the glass, they will not be.giving the light that they should, while if reflectors and front glasses are dirty the light will not be projected from the lamps to the degree that it ought to be. Assuming that _ all these points are above suspicion, it is still possible for the driving light to ho poor owing to the lamps being improperly focused, and possibly also wrongly set. One has only to watch cars at night to see many instances where such is the case, and, moreover, not only are the drivers at a definite disadvantage themselves, but they are more often than not causing dazzle to other roadusers, and so constituting themselves an actual source of danger. To obtain the best results from the headlamps the bulbs should be adjusted so that the white-hot filament is at the focal point of the parabolic reflector. Some method of adjusting the focus is provided on every type of headlamp, and while in some lamps it may be external and fairly obvious, on others .it may bo internal, so that it can only be used on taking out the reflector.

It is hardly necessary to give instructions on focusing, for who, when at school, has not used a lens to set a piece of paper on fire by focusing the rays of the sun on it? It is useful to have the car facing a blank wall while focusing the lamps approximately, and to carry out a final adjustment on a straight, level road so that the best compromise for driving may be obtained.

Having correctly focused the lamps, see that they are properly set. The beams should be projected forward straight up the road, preferably with a slight bias towards the near side, and the two beams should be parallel to one another. If the beams diverge there is apt to be a dark spot between them, while if they converge the area of light will be too small, and there will be insufficient spread of light towards the side of the road, both conditions being very tiring for the eyes.

The beams should also be approximately horizontal, for if they shine upwards much of the light will go to illuminate tree-tops and telegraph' wires; in other words, will he useless for illuminating the roads. Also, if the beams are inclined upwards they will be found very dazzling in fog or mist. If the beams are inclined downwards too much, then their range will obviously be adversely affected. It is usually easy to_ set the lamps, and in most cases a single large nut securing the lamp, in its bracket has only to be slackened a little, when the lamp can bo tapped with the palm of the hand from one position to another.After the- best setting is obtaiped the nut is tightened again. When the headlamps arc correctly focused ami set they cause no appreciable dazzle to approaching drivers if the dipping switch usually provided is used It is. therefore, a <’ood idea to get a friend to drive your owh car towards you one night. If you are dazzled by it when the lights are dipped, then check the focus and set the lamps again. Many owners forget tliat careless garage hands sometimes push a far backwards by its headlamps, which may tilt them backwards or sideways from their proper setting. HELPING BOTH PARTIES. The clipped lighting can be an advantage t<) yourself ns well as to_ other drivers, The dipped beam, being inclined downwards and to the left, can be kepf on the edge of the road so that it automatically forms an excellent guide and helps to prevent one looking

at and being dazzled by approaching lights. Then, on a left-hand bend or corner the dipped and inclined beam is a great help, whereas the normal beams shine off at a tangent. At the crest _of a hill or hump-backed bridge the dipped beam will also be found more useful than the normal_ beams. During silent periods, when signals at crossings or junctions are now given by the lamps, there are many places where a signal from the dipped 1 beam will be more easily seen than one from the normal beam, by reason that the light from the dipped and inclined beam will illuminate the roadway or the corner of a building, whereas the normal beam will shine straight ahead, and may be too narrow and far-reaching for its light to fall on anything visible to a driver approaching at right angles. IN ONE’S OWN INTERESTS. Finally, it is contributing to your own safety to keep your lamps properly focused and set, and to use the dipping svitch so as to avoid dazzling others. When two cars are approaching each other, along a curved path, such ns round a bend or over a hill, the drivers should dip just before sighting the other lamps face on. They will then avoid dazzling each other. • On the level it is sometimes difficult to know just when to dip. One may do so only to find that the distance between the two cars is considerable. In such a case it is better to remain dipped, for the human eye does not respond rapidly to sudden changes in light intensity, and to switch on to the normal beams again for a short time is likely to affect the good vision of both drivers. It is a matter of both courtesy and common sense.