US1974982A - Lamp - Google Patents

Description

SePt- 25, 1934- B. CHRISTMAS 1,974,982

LAMP

Original Filed July 30, 1931 3 Sheets-Sheet 1 A I; I:

v 7 HINVENTOR.

I Y I f urIon /zr1sim5.f

Sept. 25, 1934. B, cHR|sTMAs 1,9745332 LAMP Original Filed July 50, 1931 3 Sheeas-.Slezl 2 INIVENTOR. urina (l2 ruim (15.

1115A TTORNEY.

Sept. 25, 1934. B. CHRISTMAS 1,974,982

LAMP

Original Filed July 50, 19.31 5 Sheets-Sheet 3 Patented Sept. 25, 1934 treo STATES c were LAMP Burton Christmas, Thornburg, Pa.

Application July 30, 1931, Serial No. 553,930

Renewed August 21, 1934 Y 3 Claims. (Cl. 240-41.36)

This invention relatesto llamps and is herein disclosed as embodied in Van automobile lamp. Such lamps have been developed to a high degree of eiciency so far asconcerns throwing light 'J ahead, but the light is usually so intense that it blinds anyone who faces it, and, moreover, the light usuallyilluminates onlyv a narrow part-of the road ahead 4of the car. Besides these objections to the head lights usually used, the lights m are ineicient in fogs, because they throw a bright light diagonally upwardly, brilliantly illuminating the fog particles immediately in front of the car, and thus preventing the driver from seeing N what is beyond them.

1f According to the presentinvention these and other difficulties are overcome. In the form yof the invention herein illustrated the usual parabolic reflector is replaced by one which is partly panelled, though still approximating to a parabola. By confining these panels to the upper part of the reflector it has proved possible to reilect downwardly and fanwise on to the ground the light reaching them, thus illuminating the ground immediately in iront of the car. By retaining the true parabolic form for the rest of the reiector, the light is reilected forward. To prevent glare from blinding any approaching person, the front part of the light bulb is shown as silvered, and the silvering is shown as extending back to the lowest point of curvature on the lower part of the bulb, thus making any reilector unnecessary at the bottom, forward of the bulb. As a result the light which normally is most blinding, the direct light and that from the lower part of the reilector, is cut out. Moreover the silvering on the bulb cuts out uprising rays which would blind the driver of the car in a fog.

To reduce theabsorption of light by the front glass, and to reduce its distortion and backward reiiection the glass may be so bent that the rays of light, at different points, all strike the glass substantially at right angles, the angle of minimum reflection. 45, Other features and advantages will hereinafter appear.

In the accompanying drawings: Figure 1 is a sectional side view of a headlight embodying the present invention.

Figure 2 is a front view of the same on the line 2-2 of Figure 1.

Figure 3 is a horizontal section of the same on the line 3 3 of Figure 2.

Figure 4 is a sectional side view of an alternative form of reflecting lamp.

'Figure 5 is a front view of the lamp shown in Figure 4. Figure 6 is a diagrammatictop View of an automobile showing some of the light rays as projected'by the reflector of the present invention.

Figure '7 is a larger view of the headlight as embodied in its casing. Y

The headlight 10 of the present invention is shown as mounted" in any desired manner on the frontof an' automobile 12, at the center of the hood. The car also includes one form otusual headlights- 11. The headlight l0 includes a' bulb 13 having a base 14 mounted in any desired or suitable focussing mount, the bulb including'one forml of two separate laments 15 and 16, so that light may be directed somewhat downwardly close to the car'by lighting the top `filament 15, or may be directed far aheadby lighting the lower lamen't linstea'd.

V'The headlight 10 is shown as lhaving a top 17 projecting forward beyond the bulb 13, about tov the usual extent, andthe part 19 of the reflector 18 adjacent the bulb 1 3 may be of the usual parabolic form, throwing light straight forward as shown at 2O in Figure 1. Thev upper partof'headlight 10 forming an ex'tensionof the parabolic surface, is providedV with reflecting flat faced panels' ,21, approximately roughly to the usual parabola surface. In the form 'herein illustrated there is one top panel 21, and four side panels 21 on each side of the top panel. f

Such panels, whenvboundcd by linesv 22 which look straight and vertical to an observer standing in front of the headlight 10, are found to reilect or fan .the light sideways, asA diagrammatically shown at 23 and 24, Figure 6. In the form illustrated the top panel 2l extends Vabout halfway.

back down toward the `base 14, so that its back lies in a vertical plane a little 'clear ofthe outer ends of the nlaments 15 and 16. The side panels also are shown as extending back and terminating at the same plane, so that their rear edges 25 approximate to a circle, where they merge into the parabolic mirror, except that the extreme side panels are shown as terminating along horizontal lines at the horizontal axis of the reflector, so that the panels form a crescent.

The outer end of the bulb 13 is shown as silverplated at 26, so that no direct light from either filament can escape in front of the top reector panel 21, the silver plating being carried further back at the bottom of the bulb so that it reaches to the lowest point of curvature there, and terminates along a diagonal plane at intermediate levels.

If desired the bulb 13 may be paneled where silvered, thus adding to the fanning out of the light. Since the silvered area of the bulb cuts 01T any direct light from the filaments 15 or 15 which would reach the reflector in front of a diagonal plane 27 passing clear of the bulb 13, the reflector and headlight may be cut away along that plane beginning at the top 17, and there may be provided a glass `or lens 28 at that plane, held by a suitable fastening ring 29.

The bottom of the reflecting surface, all of it below the center of the bulb 13, is shown as parabolic. As a result of this structure the rays of light 23 and 24, which strike the ground go through the glass 28 at the most eflieient angle, thus facilitating effective illumination of the ground immediately in front of the automobile, and this light largely comes direct from the lilament 15 or 16 to the panels 2l and thence to the ground. Other rays have come from the filament to the silvered area and thence, by reflection, to the panels, and then to the ground. The latter are further fanned out because they come from beyond the focus which is at the filament.

To avoid the sending of the light rays from the lower parabolic mirror through the diagonal glass 28 near its bottom, the alternative structure shown in Figures 4 and 5 may be used. In this form of the invention a modified form of reflector 18 is provided, enabling a modified form of lens 30 to be used so that most of the light rays strike and pass through the ilat surface of the lens almost at right angles.

For this purpose the lens 30 is provided with a vertical bottom section 31 extending up beyond the bulb 13, and is also provided with an upper inclined section 32 extending down from the top 17, preferably reaching down to or below lower back ends 33 of the panels 21, and at that line 34 meeting the vertical section 31. For optical purposes the sections 32 and 31 are preferably molded with ilat faces from a single continuous piece of glass.

In the structure shown, the line 34 is a curve, springing from about the axis of the reflector at y the edge, where it may rise above the back ends 33 of the side panels 21. The upper, inclined, section 32 is set at such an angle that the rays from the reflector which pass through it, strike it vertically. The upper section 32 is most effective when it transmits as much as possible of the light coming from the panels 21, but does not interfere with much of the light coming from the true parabolic surface 19. For this reason, as clearly shown in Figure 5, it is usually preferable to carry the line 34 somewhat below the back ends 33 of the center panels.

The bulb 13 illustrated is shown as having vertical panels 37 where silvered, and this form, if used, aids in fanning out the light.

As clearly appears from Figure 4, this form of upper section 32 will have its edge curve forwardly beginning at the outer ends of the line 34. The reflector, and any outer casing it may have, therefore, curve forwardly along their outer edges as seen at 35.

As clearly appears from Figures 1 and 4, the panels 21 deviate from the true parabola in such form that they throw the light downward enough to strike the ground near the car. Also, as shown in Figures 1 and 2, the reflector and other parts will fit inside the space bounded by the line 36 which indicates the outside of a type of headlight often hitherto used.

Having thus described certain embodiments of the invention, what is claimed is:

1. A headlight including a bulb having a lament and a mirror of parabolic form close to the bulb and extending on all sides well out toward a vertical plane through the filament, a mirror on the bulb reflecting backwardly all rays from the filament that would reach the eye of a person facing the headlight, and a crescent-shaped l mirror composed of flattened panels, each panel extending upwardly from the edge of the parabolic form mirror and adapted to disperse diagonally downward the rays of light striking it.

2. A headlight including a bulb having a filament and a mirror of parabolic form close to the bulb and extending on all sides well out toward a Vertical plane through the filament, a mirror on the bulb having flattened areas to reflect back and fan out all rays from the filament that would reach the eye of a person facing the headlight, and a crescent-shaped mirror composed of' flattened panels, each panel extending upwardly from the edge of the parabolic form mirror and adapted to disperse diagonally downward the rays of light striking it.

3. .A headlight including a bulb having a ilament and a mirror of parabolic form close to the bulb and extending on all sides well out toward a vertical plane through the lament, a mirror on the bulb having flattened areas to reflect back.

and fan out all rays from the lament that would reach the eye of a person facing the headlight, a crescent-shaped mirror composed of flattened panels, each panel extending upwardly from the edge of the parabolic form mirror and adapted to disperse diagonally downward the rays of light striking it, and a transparent protecting glass lying vertically in front of the parabolic form mirror but having a crescent-shaped upper portion inclined at such an angle that light from the flattened panels passes through it nearly at right angles.

BURTON CHRISTMAS.

Images