US2196548A - Highway lighting apparatus - Google Patents

Description

p 9, 1 40. M. coHu ML 2,196,548

I HIGHWAY LIGHTING APPARATUS Filed Nov. 19, 1936 3 Sheets-Sheet 1 I //vvE/v7'07? April 9, 1940.

M. COHU El AL HIGHWAY LIGHTING APPARATUS a Sheefs-Sheet 2 Filed Nov. 19, 1936 llllll-I'l'll lilllllllll-ll LllIfill-lnll P 1 M. COHU ET AL HIGHWAY LIGHTING APPARATUS 3 Sheets-Sheet 5 Filed' Nov. 1 9, 1956 Patented Apr. 9,1940

HIGHWAY LIGHTING APPARATUS Merry cent and Alfred Trequigneaux, Paris France, assignors tov Societe' Anonyme ies Ancjens Etablissements Saunier Duval Frisquet,

Paris,'France, a. company of France I "Application November 19, 1936, Serial No. 111,736 In Fran c v m er25,1935

Claims. (014210-29 The present invention relates to lighting apparatus for roads, streets and the like.

The object of the invention is to provide an apparatus of this kind whichpermits of seeing in a. satisfactory mannerduring nighttime obstacles and o h r objects; present on the. surface of the road, especially v hen said surfaceis Wet. and has a low diffusing power; I Y

The apparatus according to the present inven-.

10' tion consists, on the. one hand, of a light source,

incandescence lamp, gas mantle, low or high pressure discharge luminescent tube, etc., and, on the other hand, of. reflecting. surfaces intended to dis tribute the light in directions parallel to the axial 14$ plane of the roadway -(this expression axial plane is intended to mean a plane, generally a vertical plane, passing through the axis of the roadway). These surfaces perform two chief functions; 2 a. .The central mirror structure returns to a great distance thelight flux emitted bythe lamp, in directions close to the axis of the, road, in such manner as to create a certain uniformity offil: lum nati n whi h also permits of. obtaining a u i n y niform brilliancy in, the case of a roadway surface that diffuses ina. suitable man-. ner.

mer t, the light flux directed by means of said central surface or surfaceswillhe limited be.-

tween. two ver ica planes; located on either side of the axial verticaliplane of'the-roadwayand.

making each an angle, of 50.60 with said. axial vertical plane. 1

b. The lateral mirrorelements located oneither side of the central surtaces will act uponthe light flux emitted by the lamp in directions transverse to the axis of the road (as a rule, this fluxisbadly utilized orremainsv unemployed in many of the apparatus used at the present time) in 'such manner'as to direct this flux. also in'directions substantially parallel to, the axis of the road so that these lateral surfacescorrespondto the ore ation of further bright bands on, the surf-ace of the roadway. v 1

The central and lateral elements of the mirror consist of reflectin surfaces such. as, obtained withpolished metals (silver-plated, chromium+ p e c l e d as or pri matic, la s; syn

terns acting either byrefraction or by total res fiection.

The apparatus accord ng to the. resent} invention will have an elon ated shape. inadirection at'right angles to the, axisoi the mad;

They will bearra 'ged stageenedrelatione For i st ce accordin to a preferred embodiship to one another in the transverse direction of the road in such manner that the wide luminous bandsthey' produce are juxtaposed.

Other featuresof the present invention will specific embodiments thereof. 1 Preferred embodiments ofthe present invention will be hereinafter described; with referenceto the accompanying drawings, given merely by way of example, and in which: I m

1 shows a mirror according to the invention in section by a plane parallel tothe axisof the roadway to be illuminated; I

2 is a section of the, same mirroron the line I I.-I I of Fig. 1, that is to say in a plane 15 at rightang-les to the axis of the roadway;

3 shows a section of themirror by a horizontal plane containing line. lII-III;

Fig-; {l is a view similar to Fig. 2, showing a modification; no Fig. 5 is a section of this modification on the line V-.-V of Fig. 4;

' Fig; G is, a plan view of another modification;

Figs. 7 and 8 are explanatory views illustrating the use. of mirrors. according to the invention for the illumination of a roadway; and I Fig, 9- represents a mirror according to the present invention shown in projection on the vertical plane perpendicular to the axis of the highway;

In. the, drawings, reference character a desig resultjr n the following detailed description oi .nates elements of reflecting surfaces constituting the central part of the mirror and which includes lowersurfaces a consistingof portions of paraboloids and a spherical upper surface S, so as to M recuperate an important portionof the flux. The centerof the sphere and the focus of the paraboloids are located at ion the light source close to the plane separating surfaces (1, and S "from each other. i v. I ,b is one of the two lateral elements of the mirror. Each of these two lateral surfaces, only one of which is shown in' Figs; 2 and 3, is constituted in this example by juxtaposedseparate mirrors 7' of suitable curvature and direction.

In the modification of-Figs4 and 5, the elementary'mirrors which constitute the lateral parts li -include each: 1'. a. lower part r consistingof an element ofv a paraboloid having. its. focus on the light source and the; axis: of which is located in the vertical J plane. parallel. to the axis. of the'road passing throu h said source; Y

2,; an upper partr consisting of, a'portion. of a enneia c ne: of evolution f0 n nce havin surfaces, which are of smaller size.

, various possible positions of the observers.

its apex at c on the axis passing through the light source.

The parabolic lower portion 7 returnsthe light rays parallelly to its axis, whereas the upper part 1' ensures a relatively wide dispersion of the rethe axis of the roadway. The lateral parts b of the mirror are provided, at their ends, with a portion of an elliptic mirror e one of thefocuses of which coincides with the light source located. at f, while the other focus is at f1. .Between the portions of paraboloids T having their focus at f as above explained, are provided other portions of paraboloids is having their focuses at f1 and the axes of which are in the vertical plane passing through hand parallel to the axis of the road. The light rays issued from f and striking paraboloids T are reflected as above toward the axis of the road. The light rays that do not strike the paraboloids r strike ellipsoid e and are reflected by passing through f1, after which they strike paraboloids rs which reflect them parallelly to the axial plane of the road.

Of course the ellipsoid has been given only as an example of a suitable'reflecting surface arranged so that the focus f of paraboloids 1a is placed on the image of the source given by said surface.

The apparatus that have been just described give, by reflection upon roadways which arelittle diifusing or moist, wide bright bands, themselves constituted by the juxtaposition of the bands corresponding to the central and lateral reflecting The width of the apparatus, and therefore that of the bands, may, by way of example, be about two meters.

In order to obtain a uniformly bright appearance of the roadway, the present invention includes a particular arrangement of the apparatus which will juxtapose the bright bands for the It will be advantageous, according to the present invention, to abandon the old arrangements of the apparatus all in axial or lateral position, and to combine these arrangements, and also eventually to place said apparatus in intermediate positions between the axis and the sides of the road.

By way of example, Figs. 7 and 8 show "a possible arrangement of the apparatus In these figures we have shown in a diagrammatic manner the light bands created on a rectilinear and plane road by apparatus F1, F2, F3, F4 as seen by an observer moving along the road. Fig. 7 corresponds to a positionof the observer, and Fig. 8 to another position. It will be noted that, from a 1 certain distance of the observer, the light bands cover the whole area of the road. The crosshatched portionsin Figs. 7 and 8 showthe zones that are not covered by luminous bands and for which the object, located at a small distance, will be made visible by the contrasts existing between its own parts. If the visibility of the objects is considered as insufficient in these zones, it is possible to make use of apparatus of larger size or to associate several of these apparatus in such manner that they constitute a continuous line.

As illustrated in Figure 9 the mirror is preferably placed so that its larger'ax'is is perpendicular to the longitudinal axis of the highway. It may be suspended, for example, by chains 2 from a continuoussources formed, for instance, by the juxtaposition of a plurality of lamps of small or mean power. f

In a general manner, while we have, in the above description, disclosed what we deem to be practical and efficient embodiments of the present invention, it should be well understood that we do not wish to be limited thereto as there mightbe changes made in the arrangement, disposition and form. of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims. v I

What weclaim is:

1. An. illuminating apparatus for a roadway which comprises, .in combination, a light source and a composite mirror of elongated shape having its length at right angles to the axis of the roadway and including a central structure comprising at least two reflecting paraboloid mirror surfaces having both of their respective focuses on said source and their respective axesin a vertical plane passing through said source and parallel to the. axis of the roadway, said axes being inclined and passing through the opposite ends, in the direction of the roadway axis, of the field to be illuminated, and twolateral mirror strucing its length at right angles to the axis of the roadway andincluding a central structure comprising at least two reflecting paraboloid mirror surfaces having both of their respective focuses on said source and their respective axes inha vertical plane passing through said source and parallel'to the axis of said roadway, said axes being inclined and passing through the opposite ends, in the direction of the roadway axis, of the field to be illuminated, said central structure being limited by two planes passing through said source and making an angle of at most with said vertical plane and on either side thereof, respectively, and two lateral mirror structures located on either side of said central structure along saline at right angles to said vertical plane, each of said lateral mirror structures including a series of parallel vertical steps arranged to reflect light rays from said source parallelly to said vertical plane.

3. An illuminating apparatus for a roadway surfaces in the form of portions of paraboloids having their focuses on said source and their respective axes parallel to said vertical plane but oblique with respect to a horizontal plane.

4. An illuminating apparatus for a roadway Y which comprises, in combination, a light source and a composite mirror of elongated shape having its length at right angles to the axis of theroadway and including a central structure which comprises at least two reflecting paraboloid mirror surfaces having both of their respective focuses on said source and their respective axes in a vertical plane passing through said source and parallel to the axis of said roadway, said axes passing through the opposite ends, in the direction of said roadway, of the field to be illuminated, said central structure being limited by two planes passing through said source and making with said vertical plane and on either side thereof an angle of at most 60, two lateral mirror structures located on either side of said central structure in a direction at right angles" to said vertical plane, and a reflecting surface at the outer end of each of saidlateral mirror structures adapted to give animage of said source, said lateral mirror structures including parabolic elementshaving their focuses on said image and adapted to reflect the light rays from said image to aremote point of said roadway,

parallellysto said first mentioned vertical plane.

5. An illuminating system for a roadway which comprisesin combination, a plurality of illuminating apparatus comprising each a light source and a composite mirror of elongated shape having its length at right angles to the axis of the roadway and including av central structure comprising at least two reflecting parabolic mirror surfaces having both of their respective focuses on said source and their respective axes in a vertical plane passing through said source and parallel to the axis of the roadway, said axes passing through opposite ends, in the direction of the roadway axis, of the field to be illuminated, and two lateral mirror structures located on either side of said, central structure along a line passing throughsaid source and at right angles to said plane, each ofsaid lateral mirror structures including a series of parallel vertical steps arranged to reflect light rays from said source into directions parallel to said plane, said plurality of apparatus being arranged in staggered relationship on the road in such manner that the respective light bands emitted by said apparatusare substantially juxtaposed to one another on the surface of the roadway.

MERRY'COHU.

Q G UX

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