US1328607A - Electric headlight - Google Patents

Description

0. WINSTON.

ELECTRIC HEADLIGHT. APPLICATION, FILED JUNE 28. 1915.

Patented Jan. 20, 1920.

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ELECIRIC HEADLIGHT. APPLICATION FILED JUNE 28.1916.

1,328,607, Patented Jan. 20, 1920.

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OVERTON WINSTON, 0F MINNEAPOLIS, MINNESOTA.

ELECTRIC HEADLIGHT.

Specification of Letters Patent.

Patented Jan. 20, 1920.

Application filed June as, 1916. Serial No. 106,37 3.

rangement of light dimming surface and shifting light source within a concave reflector, whereby, even when high power light bulbs are employed, blinding is prevented by dimming of the main portion of that part of the direct light beam that is above the axis of the reflector. The shifting .light' source is preferably a two-filament light bulb and the light dimming surface is preferably applied directly to the globe of the light bulb.

In the accompanying drawings which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings:

Figure 1 is a front elevation of the head light embodying my invention;

Fig. 2 is a vertical section taken on the line 00 x of Fig. 1;

Fig. 3 is a horizontal section taken on the irregular line m m of Fig. 1;

Fig. 4 is a view corresponding to Fig. 1, but illustrating a slightly modifiedl construction;

Fig. 5 is a vertical section on the line 02 m of Fig. 4;

Fig. 6 is a horizontal section taken on the irregular line 01 as of Fig. 4;

Fig. 7 is a view corresponding to Figs. 1 and 4, but illustrating a further slightly modified arrangement;

Fig. 8 is a vertical section taken on the line x m of Fig. 7; and

Fig. 9 is a horizontal section taken on the irregular line 00 00 of Fig. 7.

Referring first to the construction illustrated in Figs. 1, 2 and 3, the numeral 10 indicates a concave reflector of parabolic or similar form, and the numeral 11 indicates an electric light bulb having two filaments, the hot spots of which are indicated at a and Z). This light bulb is, or may be of the characterdisclosed in my prior application S. N. 86,852, filed March 27, 1916, and entitled Headlights, and by reference to which it will be noted that either of the two filaments may, at will, be utilized as the light source. 7

The point a may be assumed to be the focal center of the reflector 10, while the point I) is offset above the point a and located forward of the same. On its upper forward portion, the globe of the light bulb 11 is; provided with a translucent portion 12 fliereln deslgnated as a light dimming surface and which may be formed in various different Ways, as by frosting, sanding or coloring. The upper margin of this light dimming surface 12 follows a curved line that is intersected by lines above a horizontal drawn from the hot spot I) to the upper and side edge portions of the reflector 10. The lower margin of the said light dimming surface 12 is in a horizontal plane that "intersects the said point I). The remaining portion of the globe of the bulb is clear. \Vith this arrangement, when the light source is at I), that portion of the light beam that is produced by direct light rays and is above the horizontal plane of the said point 6 will be dimmed and blinding efiect is thereby prevented. When the light source is at a, the upper portion of the direct ray beam will be slightly upward and there will be a somewhat greater direct ray projection than when the said light source is at b, but a very considerable part of the upper portion of the direct ray beam will be dimmed. The light source at I) gives the best beam projection for city driving, while the light source at a gives the best projection for country driving, or where a longer and less obstructed light beam is desired.

In a two -filament lamp, the filament whose hot spot is indicated at a may have greater candle power than the filament whosehot spot is indicated at b. In this way, also, the desired variation for city and country driving may be further accomplished.

In Figs. 5 to 9, inclusive, parts corresponding to those ]11Sl3 above described are indicated by like characters.

In the arrangement shown in Figs. 4, 5 and 6, the axial filament a may be assumed to be at the focal center of the reflector, but the oflset filament b is located in a vertical line above the said filament a. The lower margin of the light obstructing surface 12 is in the horizontal plane of the point I), and the upper margin of said light obstructing source is on a curved line intersected by radial lines drawn from the said point I) to the upper and side edge portions of the reflector.

In the construction illustrated in Figs. 7, 8 and 9, the offset filament I) is located above and to the rear of the axial filament a, but the above stated plan of applying the light 'dimming surface 12 is adhered to.

Of course, in practice, the filaments of the lamp will not be confined to the spots a and l) and there will be some of the less intense rays that do not follow precisely the lines stated. but the general effect is as described.

The term axis is herein used in a liberal sense to indicate the approximate central line of the reflector, and regardless of whether or not the said reflector has a true axis of rotation.

It should be further understood that when the light source is shifted to the vertically offset point 7), there will be a much greater downward deflection of the reflected beam than when the light source is at a, and that the effect of this is to throw the greater part of the reflected beam below the axis of the reflector. Otherwise stated, when the lightsource is at 7), there will be a greater intensity of light in that portion of the light beam that is below the axis of the reflector. than there is in that portion of the beam that is above the said axis. This shifting, in itself, at least to a very considerable extent, prevents blinding effects by the reflected beam, but does not, of course, prevent blinding effects from the direct beam.

The dimming surface located as described, is therefore of the utmost importance, both when the light source is at a, as for long distance projection, and when the light source is at b, as for short beam projection. There is, therefore, an important relation between the reflector, the shifting light source and the properly located light dimming surface.

lVhat I claim is:

l. The combination with a concave reflector, of a light bulb within said reflector having two filaments, one in the axis of said reflector and one above the axis of said reflector, said bulb having a light dimming surface, the lower margin of which is in the horizontal plane of said vertically ofi'set filament and the uppermargin ofwhich is on the line intersected by lines radiating from said offset filament and intersecting the upper marginal portion of said reflector.

2. The combination with a reflector, of a two-filament light bulb having the hot spot of one of its filaments in the axis of said reflector and having the hot spot of its other filament above said axis, and a light dimming surface applied on the globe of said bulb with its lower edge above the horizontal plane of said axis and forward of vertical lines intersecting the hot spots of said two filaments.

In testimony whereof I affix my signature in presence of two witnesses.

OVERTON WINSTON. Witnesses:

BERNICE G. WHEELER, HARRY D. KILGORE,

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