San Antonio light. [volume] (San Antonio, Tex.) 1911-1993, 1923-04-29
GOOD LIGHTS
GREAT AID To
THEM0T0R|ST
Use Of DINNERS Unneces-
sary When Lamps Prop
T. erly Adjusted.
LENSES HELP SOME
But Few Such Devices Can
Really Be Called
Successful.
LENSES HELP SOME
A good automobile headlight witt

by the bureau of standards of the
Department of Commerce. The road
is brightly lighted for several hundred
feet ahead. yet there is quite a sharp
cutoff line at the level of the lights.
and above that level there is not suf-
ficient glare to dazzle driver APP
preaching from the opposite direc-
ton.
When two cars passing each other
arc equipped with such lights the use
Of DINNERS is neither necessary nor
desirable. The bright light on the
road enables the driver to see beyond
the approaching car. but there is
no glare in his eyes or on his wind
shield.
Few cars are equipped with really
good lights. Most of them become
badly adjusted, after service. and
there are many types of lenses on
the market which fall short of the
ideal requirements.
The object of using lenses or other
devices instead of plain glass is. OF
course. TO prevent glare. Many de.
vices have been tried, but not a great
many can be really called success.
full.
ne InOsl 'DNlpus hitlhOu w
of is to scatter the light. For this
purpose some use ground glass, or
glass otherwise roughened others use
various types of irregular surfaces,
such as small lenses scattered all over
the lens like the eye of fly, circular
prism sections, etc.
All OF these methods work by scat
tering the beam. If they make the
glare less intense they also reduce
the illumination on the road. and
the same effect could be obtained by
using a lamp Of lower candlepower
Fluted Lens Desirable.
Other attempts consist of cutting
off part of the beam by means Of
: screens. etc. These are all OF doubt.
n full utility and tend TO cut down the
4 illumination without distributing the
\ light over the road. Probably the
4 least sensible Of all are those which
SsNtempt to hide the filament. The
4 direct light from this filament is
usually about twenty candlepower
whereas the beam from good reflec
tor is often twenty thousand.
I The type which first shows a com
mendable effort to make good lens
is the fluted lens. Such a lens
Rspreads the beam sideways while keep.
ing it concentrated vertically. But il
is OF even more Importance that the
beam should not rise above the level
of the lamps: and to bring this con
ditioD about with such tense it is
necessary to tilt the headlight down
Perhaps the best type of all com.
bines the fluted lens with an arrange.
ment OF prisms which serve to throw
the light downward. There are many
such types on the market. all differ
ing in details. Some of these differ
ences are introduced To improve the
distribution of the light; others to
avoid infringing someone else's.
In general, n lens of this type an
pears to be divided BY horizontal and
vertical lines into a number of sec.
lions. Closer inspection shows the
horizontal lines to be the Joining lines
bf prisms. while the vertical lines are
ridges or hollows between flutes. In
some cases, the vertical lines arc
absent. the whole outer surface being
,oncave.
Several patented types of reflectors
re so designed as TO obtain the same
istribution with plain glass, and
hese compare favorably with the
enses.
Home Tests Possible.
An adjusting station can easily be
lade. and can be set up on any level
oadway. 1t consists Of screen
bout six feet or more in length and
We feet high. On this screen is
narked horizontal line at the
eight of the headlights on the car
md two vertical lines the same dis.
ince apart as the headlights.
When using lenses that require the
sadHght to be tilted, another hori-
pntal line should be made on the
'reen below the first a distance equal
the required tilt in inches at
twenty-five feet.
The car should be placed twenty
re feet from the screen. 1t should
fully loaded and the road should
such that the parts holding the
r wheels and the bottom II the
reen should be on level with each
her.
Remove the doors or rims and lenses
ON both lamps. Cover one lamr
lille working on the other.
The lamps should be so adjusted
lat their beams are parallel and fall
the intersection of the horizontal
be with the vertical lines. In cases
here the lens. used requires a till
lower horizontal line is used. In
her cases the one on a level with
lamps is used.
Few cars are provided with means
turning or fitting the lights. They
usually aimed and tilted correctly
en- the car is made and future adj
tment in this respect is usually
tessary as result of their having
IN bent in an accident. Such ad.
tments must generally be made by
in strength and awkwardness.
Focusing the Lights.
he lights should be focused This
done in the more modern types by
ms OF screw at the back of the
IT which moves the lamp in or
until the correct position is at.
ned.
This position is specified with the
ructions for the lens. For most
ses the bulb should be at the prin-
bal focus. In this case the beam
IN the bare reflector is parallel and
the smallest possible diameter.
pther types require what is known
q rear focus. In this case the
Brxi5erges as much as possible
bout having dark center. Still
GERS require front focus, in which
l..,x. c1a-orroc e. onl