US1620202A

US1620202A - Vehicle lamp

Info

Publication number: US1620202A
Application number: US575996A
Authority: US
Inventors: Graves Arnold
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-07-29
Filing date: 1922-07-19
Publication date: 1927-03-08
Anticipated expiration: 1944-03-08

Description

March 8, 1927.;

1,620,202 A. GRAVE I VEHICLE LAMP Filed July 19 1% L Patented Mu. s', 1927.

1,520,202 UNITED STATES PATENT? .orr cs.

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vnnrcma y mu filed m 19; 1 22, Serial No. 576,996, and in Great Britain m 29. 1921.

This invention relates to lamps fitted with "reflectors and used for ohead and side lights and in vehicles, of the type in which the l ght source in combination with a small hemispherical mirror is placed inside a parabolic or similar reflector, part of the light from the source falling directly on to the reflector part on to the mirror whence it is reflected on to the-reflector. In this t e one half only of the hollow surface of t e reflector is used and the otherhalf is commonly su pressed.

,One'o the ob'ects of the invention is to overcome the di culti found with reflectors commercially obtaina le', that the optimum o si tion is not always at the geometrical ocus as 1t would be in the case of a perfect a mirror.

Another object of theinvention is to suppress rays above the horizontal and to cast the li ht in a low flat topped beam and 'so ,abolis glare, and further to make the beam as uniform as 'ossible.

A further 0 ject is to enable the user of- 3151 lamp to vary the nature of the beam at Tb attain the first object, the invention consists in mounting the source of light Swhich may be thefilament of anincanescent electric lamp) together with the small hemis herical mirror (which may be formed by silvering one half of the spherical bulb of the lamp) on the holder which is capable of movement in all three dimensions, so that the source of light together with the mirror may be brought to the optimum position in the reflector and there fixed. e

To attain the second object of the invention, the light sourceis positioned relatively to the reflector so that it is situated not at the focus or'optimum position of the reflector but in advance or in rear thereof accord ing to whether the lamp is-one in which the upper half of the reflector is being used or w ether it is one employing the lower half of, the reflectoryand .to make the beam uniform it is further preferred to positionthe light source relatively to the hemispherical mirror so. that it is not at the centre of curvature thereof but slightly in front or in rear of the centre of curvature and inthe same plane. I To attain the third object, the invention consists in so mounting the light source and lamp bodily, either of the'filaments may at. will be switched on. One of these filaments is placed at thefocus or optimum position of the reflector, and the other is so situated in relation to the first that it isfin advance or in rear of the optimum position according as the upper or lower half of the reflec tor-is used.

In the accompanying drawings which illustrate the manner in which these objects are accomplished Figure 1 is a diagram'illustrating one way of carrying the invention intoefiect in connection with an upper reflector.

Figure 2 is a view similar to Figure 1 but show ng an embodiment using a lower reflector.

Figure 3 is a view illustrating the embodiment of the invention in a com lete unit.

- .Fi 're 4; is a detail view furt er illustrating the adjusting means for the lamp.

Figure .1 shows a parabolic reflector A g whose-axis is represented by the line X- X and the focus isat F. M isa small semicircular mirror whose centre of curvature is at C. 'L and L are sources oflight, the former of which is. situated in advance of the. focus F of the reflector in the same plane{ as the centre of curvature C of the mirror M but slightly in rear of it. 'The mirrow will produce an image L of L on the other side of the centre of curvaturei Ignorin for a moment the fefl'ect of the image at the light from L as reflected byA will produce a converging beam which after coming to -a focus will again diverge to give a beam in front of the lam and below the horizontal axis XX and t is beam will have a semicircular section with a flatjtop consisting of a concentric series of semifannuli with dark interspaces. The position of L may beso adjusted relatively to M that the image L will cast a similar beam whose semi-annuli will be coincident with the dark inte aces of the beam-cast by L. The result-o this will be a nearly homogeneous beam of semi% circular section with a flat top below the horizontal and free from glare but well in front of hemispherical mirror M inasmuch as this arrangement renders the beam more uniform but if desired the light source L may be placed at the centre of curvature of the hemispherical mirror M and in such case the beam will befree from the glare eflect rovided of course that the other important feature be presented, that is to say, that the light source L shall not be at the focus F of the reflector.

As previously indicated in Figure 1 the filament L is coincident with'the focus or optimum position F of the reflector A, and when it is rendered incandescent the concentrated beam is obtained. The relationship of the filament L and its image L is as previously described, and when a flattopped anti-dazzle beam is required, the filament L is extinguished and L rendered 1ncandescent. 1

Figure 2 is similar to Figure 1, but in this case the lower half of the reflector is used. Figures 3 and 4: illustrate a practical method of carrying-the invention-into effect. An outer shell 1 together with a base 2 is mounted on a rigid frame 4 provided with lugs 3 by means of which it may be attached in any desired position. Within this rigid frame 4 is mounted a frame 5 carrying a parabolic reflector 6. The frame 5 is capable .of slight movement about pivots 7 under the influence of the screw and spring ad'ustment 8 by means of which it maybe tllted if desired. The lamp 9 has its lower portion 10 silvered and is mounted on a cylindrical spindle 10 lar 10 mounted 'on the centre of a. washer 18. This washer 18 is held .between' two rings 17 and 1'2 the latter projecting through the-plate 13. The apertures of the rings 17, 17, and the plate 13 are of greater diameter than the spindle. If the screws 19 be loosened the spindle may be moved in any direction radial to the axis of the reflector and may befixed in the optimum position by tightening up the screws 19. Longitudinal movement of the lamp may then be effected by loosening the milled head on the split collar 10 and tightening up again when the lamp has received sufficient axial.

movement to bring the source of light-in advance of the focus of the reflector. The adjustment of the beam may be effected by placing the lamp so as to cast a beam on to a vertical wall about 10 feet away and moving the bulbuntil the berm is as bright as possible, this will occur when the filament 1s in the optimum point of the reflector. The lamp is then moved axially forwards until the beam assumes a flat top semi-cirhead screwed tight. T

which passes through a split 001- cular shape without glare andthe milled e plate 13 is mounted on a spindle 14; passing through a I fixed block 15 and is capable of being pulled backwards by the Bowden wire 12 against the action of a sprin 16 so that at will the driver may alter t e character of the beam.

It is obvious that in the'case of an existing/ lamp having a parabolic or similar reflector,

such lamp might be converted to work in accordance with the invention by fixedly adapting to the reflector an attachable fitment carrying movably mounted therein a source of light, and a small hemispherical mirror, the source of li ht and the mirror being in fixed relations but capable of adjustment in the fitment as previously described relativel to the re ector A in three directions, so t at the source 0 light is capable of being brought to the focus or optimum position of the reflector and then withdrawn therefrom to another axial position by movement in the adapter fitment.

Claims:

1. A lamp of the class described including an outer shell, a main frame within said shell, a reflector carrying frame pivotally mounted insaidmain frame, screw means for adjusting the reflector carrying frame with reference to themain'frame, a lamp carrying unit including a plate having a spindle, a fixed block on the main receiving the spindle, a spring confined between the spindle and the block, a flexible connection for said spindle whereby the same may be shifted in the block to move the lamp carrier axially of the reflector,

frame for.

the axis of the reflector.

2. In a lamp, the combination of a frame,

a carrier guided on the frame for rectilinear movement thereupon between two limiting positions, a reflector, means for' mounting the reflector on the frame, said means having an adjustment for bringing the axis 'of the reflector into parallelism with the path of movement of the carrier, an electric light, means for mounting the lamp upon the carrier, said means having adjustment for bringing the filament of the light into the focus of the reflector when the carrier is in one limiting osition, and operator controlled means or shifting the carrier from one limiting position to the other with respect to the frame to chan e the character of the beam emitted by tfie-lamp while the lamp is in use.

3. In a lamp, the combination of a frame, a carrier guided on the frame for rectilinear movement thereupon between two limiting positions, a reflector, means for mounting the reflector on the frame, said means having an adjustment for bringing the axis of the reflector into parallelism with the path of movement of the carrier, anelectric light,

means for mountin the lamp upon the carlamp is in use, a second reflector within the 10 rier, said means aving adjustment for -first reflector, the focal point of the first re bringin the filament (i the light into the flector, the lamp and the second reflector focus 0 the reflector when the carrier is in, coinciding when the carriage is in the limitone limiting osition, and operator com ing position for securing a concentrated trolled means or shifting the carrier from beam. 15 one limiting position to the other with In testimony whereof I have affixed my respect to the rame to change the character signature hereto this 30th dagof June, 1922. of the beam emitted bythe lamp while the ARNOL GRAVES.