US 1346705 A
Description (OCR text may contain errors)
angles to the surface ofi the lens. Thus, light is thrown to the sides of the lamp in its nnmediate vicinity; as this action is particularly helped by the ground part atV 9 on the bell which is in advance of the pla-ne oli the lens, This part also cuts oli' the direct for- Ward glarini rays from thevlamp C. r lhe action of di usion and reflection is indicated diagrammatically in Fig. l. All rays striking the ground surface 7 are dill used and are thrown at different angles through the dass and against the front corrugations. l ovv these rays, being projected at di florent an J*les and strilcin Y the corrugation faces at di terent an les see the left hand picture of Fig. 4) an the corriwation faces being in intersecting planes, tlle result is that rays of light are thrown out sidewise from the con rugation faces at ditl'erent angles and these rays cross and interfere with each other t see the right hand portieri of Fig. Ll). The re sult is that all points at the side of the lamp are lighted by numbers of ra 7s from dili'er ent points. The side illumination 'is ei;- ceptionally uniform because the rays are very uniformly distributed.
lt will be noted that While the ground surfaces of course dilfuse in all directions, the corrugations dilfuse and deflect only horizontally. Then, all the light which strikes the ground surfaces is diffused to a certain extent in all directions, but mostly horizontally*7 and all such light, when thus diffused assists in illuminating the ground close to and at the side of the lamp. But it will be particularly noted that all li ght which would normally (by the reflection alone) be thrown upwardly, is diffused so as to be noinglaring. The small ground surface at lll performs particularly the function of dilusing that light which would normally be thrown down closest to the vehicle; and the ground surfaces at 1l perform particularly the function of diffusing the light from the center edge portions ol" the reflector and lens.
It' is obvious that l structure, which distributes the light in such a way that it is unobjectionable tothe person in the ro'adway, whether on foot or in other vehicles, and which distributes the light on the ground in the places most desired and "with the intensity most desired. ln fact the distribution is very even, and the light very intense, over a large area Which is very nearly rectangular in form. The side illumination is very goed, as is also the illumination far in advance of the vehicle, and an important feature is that the light is thrownstrongly' at right angles to the have provided a lens foryvard direction, giving an illumination overa side area close to the vehicle.
Having described a preferred forni of' my invention, what l claim is:
l. A lens, comprising a transparent body havingr a vertically tinted surface substantially entirely covering a face thereof, and a lare thereofliaving clear and translcuent parts, the translucent part surroundingl the clear part and the clear part comprising that part of the face which is bounded below by a line substantially horizontal and rhordal and near the center' oi the lens and bounded on opposite sides by lines which have a general convergency 'from near the outer ends of the chordal boundary to a point near the vtop center of the lens; the transparent body having a central v(lished part and said lower chordal boundary havingr a substantially central semifcircular up ward projection into the dished part, so that the whole center portion of the dished part is translucent.
A lens, comprising a transparent body l'laving a vertical fluted surface substann tially entirely covering a face thereof, and a face thereof having clear and `translucent parts, the translucent part surrounding the clear part and the clear part comprising that part of the face which is bounded bclow by a line substantially horizontal and chcndal and near the center of the lens and bounded on opposite sides by lines which have, a" general convergency from near the outer end of the chordal boundary to points near the top center of the lens; each of said side boundary lines extending first generally upwardly from the end of the chordal boundary and then extending sharply inwardly and then upwardly to the top of the lens, so that the clear portion of the lens is substantially of the shape of an inverted T with a comparatively wide part below` and a comparatively narrow part above, which narrow part is much narrower horizontally in comparison with the horizontal width of the lens at that point than is the Wide part in comparison with the horizontal width of the lens at its center; the lens having a central (lished portion and said lower chordal boundary having a substantially central semicircular upward projection in the dished part, so that the Whole center portion of the dished part is translucent.
ln witness that i claim the foregoin I have hereunto subscribed my naine this l21th day of December, 1918.
ADELBERT R. GIBSON. llVitness:
Vmomm I. Baumann.