US1566590A

US1566590A - godley

Info

Publication number: US1566590A
Authority: US
Publication date: 1925-12-22
Anticipated expiration: 1942-12-22

Description

C. E. GODLEY Dec. 22, 19-25- REFLECTOR ori ina Filed May 8. 19,2 2 Sheets-Sheet 1 G imu ESQ mu C. E. GODLEY Dec. 22, 925- REFLECTOR Original Filed May a. '1922 2 Sheets-Sheet 2 3 LT l H I I I Patented Dec. 22, 1925.

w UNITED STATES- 1,566,590 PATENT, OFFICE.

CHARLES E. GODLEY, OE DETROIT, MICHIGAN, ASSIGNOR TO EDMUNDB AND JONES CORPORATION, 01 DETROIT, MICHIGAN, A. CORPORATION OF NEW YORK. I

anrmc'ron.

Original application filed Kay 8, 1822, Serial 'lIo. 559,204. Iiivided. and this application filed Kay 8, 10M.

' Serial 1T0. 710,770.

To all whom it only concern:

Be it known that I, GHAaLEs E. YGODLEY,

a citizen of the United States, and residing at Detroit, in the county of Wayne and State of Michiga'n, have invented a new and Improved Reflector, of which the following is a specification.

This invention relates to the construction of the reflectors of projecting lamps, especially the headlamps of motor vehicles of the types shown in my co-pending application, Ser. No. 559,204, filedMa-y 8, 1922, of which this is a division, and its object is to so divide the reflector into sections that the rays'of light will be projected upon a clearly defined limited area and in part concentrated upon a restricted portion of such area.

Lamps equipped with the well known parabolic reflectors cannot produce this effect for when such lamps are so positioned that the concentrated light properly illuminates the roadway sufficiently far in advance to permit the driver to avoid obstructions,

the roadway nearer the vehicle is left dark, or too much light is projected upward and sidewise where it is liable to blind oncoming drivers and pedestrians.

These objections are overcome by deforming a reflector of substantially paraboloidal shape so that different portions thereof will project beams whose cross-sections are similar in shape but difi'erent'in size, and so that the larger and milder beam will afford a general road illumination of considerable spread while the more concentrated beam will afford a. driving light illuminating a narrower stretch of road for a considerable distance ahead of the vehicle.

My invention therefore consists .in deforming a substantially parabolic reflector so that it will project beams of greater width than height and in a reflector of this character which can be manufactured at approximately the same cost as an ordinary paravboloidal reflector and in which the special deformations will not interfere with the usual machine polishing of the reflecting surface.

of the general araboloidal form of the re fiector farther t an its lateral edges. I vary the depth of the convexity of the crosssection or the width of the panels according to the desired spread ofthe projected beam, and vary the relation of the central lines of the panels to .the vertical plane passing through the focal axis of the reflector according to the directions in which the beam is to be ex anded.

The cross-section 0 each panel on a line radial to the inner edge of said panel is the same as a horizontal cross-section of the same width of a determinin center of this cross-section o the determining parabola being in a line assing through the focal center of both bodies and through substantially the middle of said cross-section of said panel, but reversed. This rule holds with reflectors having panels, all of whose sides are parallel and vertical and with reflectors divided into panels of irregular form so long as the cross sections of these panels are tiltedinto the lanes in which the light is to be spread. or example, if the central lines of the panels in a headlight reflector having a horizontal axis were all in vertical planes, the beam of the reflector would be expanded from circular to elliptical cross-sections with the major axis of the ellipses horizontal. If the ends of such generally upright panels curve slightly toparabola, the.

ward or away from a vertical plane, the

transverse sections of a parabola of a much longer focus for the more concentrated light. Byusing the longer-focus transverse sections, the panels can be of any predetermined width, the spread of light being determined by the focal length of the parabola used in determining the transverse. sections of the panels.

By using transverse parabolic sections in the-panels I find that the light rays reflected from each panel diverge equally from i the axis of the reflector, the rays from each panel covering substantially the anticipated field of light of the different sections.

. I have also found that if the convexity of each panel is just the reverse of the'normal parabolic section for the same ortio-n of the reflector, using narrower pane s for greater concentration and wider panels for the more diffused light, that the width of panels are determined by the width of spread desired in the projected fields.

In the accompanying drawings Fig. 1 is v a, front elevation of a reflector embodying the present invention. Fig. 2 is a section on the line 2--2 of-Fi 1. Fig. 3 is a diagram illustrating the'lig t rays projected by the Figs. 1, 2, 1 and 2 are diagrams showing the method for determining I the proper cross sections of the paraboloidal panels. 1 I Similar reference characters refer to like parts throughout the several views.

The reflector 1 is generally'parabolic in form. If a light bulb could, be made with a filament with substantially no dimensions and this filament mounted at the focus of the reflector, then this reflector, if a perfect parabola, would project a beam of light of the diameter of the reflector. The filaments of light bulbs are, however, of considerable size so that the light projected is in the form of a cone whose surface is somewhat indefinite.

After the parabola has been formed and polished, it is placed between proper dies and its surface is deformed so as to be divided into

panels

3 and 4, those next to central aperture 2 of the reflector in Figures 1 and 2 being 'narrower than those farther away. I,

Each of these panels has substantially parallel sides and these sides are convex toward the central opening 2. I have shown the lateral curvaturesof these panels to be substantially uniform but this is not necessary as the curvature of the ends of these panelsis suflicient to project li ht toward the corners of the main pro ected eld so that instead of a circular field of light, this refleigor projects a substantially rectangular fie o The desired width of the panels being fixed, the exact cross-sections of the panels ma be determined after the manner shown in igures 1 to 2 inclusive. For any given portion of the panel 3 shown in Figure 2, I first determine the center G of the crosssection of the corresponding part of the original ortrue paraboloidal surface 1, as

shown in Figure 1*. I then draw a line from which the focal line F G intersects the determining parabola indicates the central polnt of a small sectlon of the parabola l which has the proper curvature for the desired panel cross-section. If this determining parabola is of greater focal length than the parabola 1 (which is part of the true paraboloidal surface from which the reflector is to be formed and which it will still approach rather closely when finished) this curvature is reversed as shown in Figures 1" and 1.

Cross-sections of the panel 3 at other points are similarly determined, each being taken radially to the inner edge of the panel as shown by the lines K in Figure 2 This insures. a panel which efl'ects an unusually uniform distribution of light. Owing to the resulting uniform density of the projected beam and of the beam-widening effect due to the edgewise curving of the panels, they cooperate in projecting a beam of approxi mately rectangular cross-section with its upper and lower borders substantially parallel to the plane of the line 3 in Fig. 2 The lines K indicate how the rays of light are deflected up and down so as to proceed along lines substantially at right angles to the border lines of the panels at the points of reflection.

Each of the panels resents a transversely convex surface to-war the plane of the open end of the reflector and the curvature of such panel at every point in its length is desirably the same as a horizontal cross-section of the determining reflector taken in a line passing through the focal points of both reflectors, reversed and placed so as to coin cide with the normal paraboloidal reflector surface at the edges of each panel and tilted into the planes in which the light is to be spread. The curvature of each panel is therefore greatest at the horizontal diameter of the reflector.

This parabolic transverse curvature of the several panels enables me to determinethe exact field to be illuminated by the rays reflected by each panel, and the rays of the light from each panel are projected so as to fall evenly upon the entire predetermined field of illumination, that is, illuminate evenly the field on both sides of the axis of the reflector. The angle of diffusion therefore of the rays reflected by any particular panel depends upon the focal length of the deterbe noticed that each of the panels is of subcorners of this field. This results in a field of illumination which is practically rectangular.

The panels nearer the central 0 ening of the reflector are made narrower in proportion to their depth than those farther away which results in the rays projected b :the'

comparatively more shallow panels eing concentrated on a more limited field than those projected by the comparatively deeper panels. This variation in transverse curva-- tu're of the panels may be gradual or abrupt. The central portion of the illuminated field will therefore be brighter than the outer portions and this area of more intense illumination may be moved up ordown in the field of milder illumination by tilting the general focal axis of the outer more shallow panels. The outer portions of the reflector approach more nearlya true parabola and the light projected thereby is therefore more concentrated. I prefer to tilt these panels about one degree upward so that the area of intense illumination will be positioned at the upper portion of the less intense but larger field.

Fig. 3 is a diagram showing the proportionate illuminationof a field by means of a, reflector of this character, the field being divided as showninto eighty squares, and thelength of the sides of the squares equally approximately one degree of are on a spherical surface whose. radius is one hundred feet, the general focus of the reflector being at the center of this spherical surface. With the source of illumination at the focal point 6, Fig. 2, some of the rays of reflected light are projected by each of the narrow and deeply curved panels 4 over a surface extending from one vertical line 8 to the other and between horizontal lines 0 and 4.

The side panels 3 are wider and shallower so that the light reflected by these panels is diffused to a much less extent, both horizontally and vertically, for the'reason that they approach more closely to the true parabolic reflector. Now by tilting those portions of the reflector which embody the panels 3, through an angle of about one degree, so as to swing the axis 6-7 up above the axis 68 of the remaining portion of the reflector, the area of most intense illumination is moved up.

WVhere an automobile headlight is less than four feet above the roadway, and the" rays of light strike the roadway about two hundred feetfrom the-vehicle, the width of the area of intense illumination should be that of the roadway and it may extend about one hundred feet toward the vehicle; The

area of less intense illumination derived from the more convex panels Wlll extend over-this same distance and in addition thereto, extend over space on each side'of the more intense field andbetween it and the vehicle. 4

' The comparative widths of these panels and their curvatures relative to the central vertical plane of the. reflector may. all be changed by those skilled in the art without departure from the spirit of my invention as set forth in the following claims.

I claim 1. A paraboloidal reflector composed of a group of panels on each side of the center of the reflector, the panels on each side of the center ofthe reflector being substantially .parallel to each other, each panel beingt transversely convex toward the general focus of the reflector and 1ts transverse curvature at each point being the same as that of the general curve of a parabola at that point but 111 the opposite direction, the edges of the panel being convex toward the general axis of the reflector.

2. A paraboloidal reflector composed of a group 0 panels on each side of the center of ture at each point being the same as that of the general curve of a parabola at that point but in the opposite direction, the edges of the panels being convex toward the general axis of the reflector, the panels on each sideof the reflector being divided into inner and outer groups, the panels of oneof the groups on each side being deeper in proportion to their width than those of the other group on that side so as to produce a greater diffusion of light.

3. A paraboloidal reflector composed of'a group of panels on each side of the center of the reflector, the panels on. each side of the center of the-reflector being substantially parallel to each other, each panel being transversely convex toward the general focus of the reflector and its transverse curvature at each point being the same as that of the general curve of a parabola at that point but in the opposite direction, the edges of the panels being, convex toward the general axis of the reflector,-the panels on each side of the reflector being divided intov inner and outer groups, and the general focal axis of the inner groups being at an angle to the general focal axis of the outer groups.

4. A paraboloidal reflector composed of a group of anels on each side of the center of the re ector, the panels on each side of the center of the reflector being substantlally parallel to each other, each panel being transversely convex toward the general focus of the reflector and its transverse curvature at each point being the-same as that of the general curve of a parabola at that point but in the opposite direction, the edges of the panels being convex toward the general axis of the reflector, the panels on each side of the reflector being divided into inner and outer groups, the panels of the inner grou sbeing deeper in proportion totheir wi th than those of the outer groups, and the general focal axis of the inner groups being at an angle to the general focal axis of the outer groups but in the same plane. 4 i

5. A parab 'loidal reflector'composedof a group of panels on each side of the center of the reflector, the panels on each side of the center of the reflector being substantially.

parallel to each other, each panel being transversely convex toward the general focus of the reflector,-the edges of the panels being convex toward an axial plane of, the .reflector.

6. A paraboloidalreflector composed of a group of panels on each side of the/center of the reflector, the panels on each side of the center of the reflector being substantially parallel to each other, each panel being transversely convex toward the general focus of the reflector, the edges of the panels being convex toward the general axis of the reflector, the panels on each side of the reflector being divided into inner and outer groups, the panels of the inner groups being 'deeper in proportion to their width than those of the outer roups so as to produce a greater lateral dlusion of light.

7. A paraboloidal reflector composed of a group of panels on each side of the center of the reflector, the panels on each side of the center of the reflector being substantially parallel to each other, each panel being transversely convex toward the eneral focus of the reflector, the edges'of t e panels being convex towardthe general axis of the reflector, the panels on each side of the refiector bein divided into inner and outer roups, angfthe'general focal axis of the inner groups being at an angle to the general 7 focal axislof the outer'groups. A paraboloidal re ector composed of a group of panels on each side of the center of the reflector, the panels on each side of the center of the reflector being parallel to each 1 other, each panel being transversely convextoward the general focus of the reflector, the middle portions of. the panels being "nearer the general vertical plane of the re flector than their ends, the panels nearer said plane being narrower and more convex in transverse-cross section ther away from said planet 9. A paraboloidal, reflector composed of a than those fargroup of panels on each side of the center of the reflector, the panels on each side of the center'of the reflector being substantially parallel" to each other, each panel being transversely convex toward the general focus of the reflector, the edges of the panels being panels all being in a common paraboloidal surface.v Y

" 5 ,CHARLES E. GODLEY.