ANTI-DAZZLED PROBLEM

NZ Truth, Issue 1228, 13 June 1929, Page 19

ANTI- DAZZLED PROBLEM

Engineers Always Searching For Perfect Headlight SOME NOTED IMPROVEMENTS "

Motorists have wondered why inventors, who seem to be working on anything and everything, do not get busy and develop a headlamp which would give all the light needed on the road and still not glare at all.

A CTUAL/LY numerous small changes r\ m the past four or five years m the aggregate .have produced a decided improvement m modern headlights: This is, evident to ..anyone .who coniDiirefj riding at nitftit behind the wheel of a: 1928 or 1929. car with his experience m a] 923 car.' '•';.'. ;•■ A visit., to Genei al j\T6t.prs.>.Research Tiab oratories would cori-vincfe anyone that this problem is receiving its full share ■of atten tion and also that the solution is not entirely so simple as.it may seem to be, • A lorii?, wide 'room m the General M.otors building Detroit is /painted black. Along tlieside walls are-dozens of headlamps gathered from all over the world. . The room itself is arranged to look like a road. Signs andtest objects are placed here and'there. In the background a car is narked aa though it were annroaching. When thejjieadlamps at one end of the room.ai'e 'turned' on, the laboratory looks like. a country road at night. In the^fpreground is a pedestal and on this four frames are mounted m a row, m which reflectors, lenses, and bulbs may be assembled as desired. "Two pairs of different headlamps may* b& set up side by side and their performance compared by switching from one to the other. Or the bulb may be moved around' ln a headlamp through known distances m various directions to. determine how sensitive the lamp is to slight variations; A favorite method of developing a new lamp is to put four similar refleccors- m the frames. Portions of each

reflector are covered so that the uncovered portions of all four when taken together are equal to one complete reflector. Then the parts are tilted and swung with reference to each other and a beam of light built up which can later be incorporated m a single reflector. A new lens 1 is developed by assembling prisms and pieces of fluted glass over the reflectors; and light is distributed by the lenses <on and above the road m any desired manner. A ride at night m a special headlighting test car would prove that modern headlamps are able to do practically anything desired m lighting, but ... lamps must, be properly adjusted to obtain these results. Every, car •* owners

manual includes instructions on headlamp adjustment. A small screw at the back of almost : every headlamp should be used to move the bulb ahead and back m the reflectoi to compensate, for variations m buibs iindjocate the light source correctly. • . By. this means the rays may be bunched into a beam, which reaches fai : ahead of the car and well to the side tc light ditches and. turns. The universal joint under each lam]: should be used to, aim. the beam just below the other driver's eyes where- it will light the road and not glare, fov glare is nothing more than misdirected ; light. Lamps get out of adjustment at some time or another, and many thoughtless owners permit them to stay out, not [ realising how much it means to themselves as well aa others, to neglect this important Item. . .. , Even with headlamps adjusted properly, loading the rear seat does, at times, raise the powerful beam* into the other driver's eyes. Springing caused by irregularities m the road surface also gives some trouble. Dimming lights by materially reducing the candle power is extremely dangerous. It is just as important to have sufficient road illumination as to avoid glai\e. Depressing the beam' avoids glare without sacrificing road illuminai tion. The past few years have seen a revolutionary headlighting development: Depressible beam lamps have come into general use. Instead of dimming, the driver merely . switches from one 21---candlepower filament m the bulb to its

mate placed about one-eighth of ar inch above it. This drops the beam so that it does not reach more than one hundred feel or so ahead of the car. The glaring rays are then far enough below th( other driver's eyes to avoid trouble. Despite such improvements, night driving conditions are by no means perfect, largely because many motorists have not taken advantage of t}ie possibilities m their headlamps. . ' Good results cannot be obtainec without the co-operation ■ -ot i . tin motorist on the matter of adjustment. The. problem, then, . for research engineers, has been to develop a lam] that motorists can adjust easily anc accurately.