US2035215A - Reflector - Google Patents

Description

L. A. BEAN REFLECTOR March 24, 1936.

I Filed Nov. 15, 1953 [mm/2221'; [0411377. Bean. 7 Q MM Patented Mar. 24, 1936 UNITED STATES PATENT, OFFICE REFLECTOR Louis A. Bean, Denver, 0010.

Application November 13, 1933, Serial No. 697,751 3 Claims. (01. 240-103) This invention relates to light-reflecting devices and apparatus, and more particularly to such devices and apparatus employed for the illumination of relatively large areas, and has as 5 an object to provide a novel and improved reflector for the purpose set forth.

A further object of the invention is to provide an improved reflector operable in combination with a light source to illuminate a relatively large area with high efficiency.

A further object of the invention is to provide an improved reflector operable to efliciently diffuse the light emanating from a source over a relatively large area.

A further object of the invention is to provide an improved combination of curved reflecting surfaces operable to efficiently diffuse the light emanating from a source over a relatively large area.

A further object of the invention is to provide an improved combination of curved reflecting surfaces operable to enhance the uniform character of light projected thereby.

A further object of the invention is to provide an improved combination of curved reflecting surfaces operable to minimize glare in the light projected thereby.

A further object of the invention is to provide an improved combination of curved reflecting surfaces operable to efficiently project light with a minimum of glare-producing parallel or convergent rays.

A further object of the invention is to provide an improved unitary reflector assembly including improved means for adjustably mounting the said assembly in operative position.

A further object of the invention is to provide an improved reflector particularly adapted for flood-lighting purposes and arranged for convenient, adjustable mounting.

My invention consists in the construction, arrangement and combination of elements hereinafter set forth, pointed out in my claims and illustrated by the accompanying drawing, in which 7 Figure 1 is a front elevation of my improved reflector positioned for practical, use. Figure 2 is a rear elevation of the showing of Figure 1. Figure 3 is a section taken on the vertical median line of the showing of Figure 1. Figure 4 is a half-section taken horizontally of the showing of Figure 1.

In the construction of the improved reflector as shown, the numeral I0 designates the body portion or shell of the reflector, which element is formed integrally of any suitable material, such as metal, by moulding, stamping, or otherwise, as may be found most desirable. The shell Ill is approximately circular in elevation and is preferably finished with an annular rim or flange II to provide convenient means for mounting a protecting lens in closing relation with the concaved portion of the reflector. The area of the shell l0 within the rim II is concaved to a vertex positioned in the vertical median plane of said shell and some distance below the center pertaining to the rim II, the reflecting surface thus developed being a smooth concavity presenting a curvature, where intersected by the vertical median plane, closely corresponding with a segment of a convolute or spiral positioned with its lesser radiants 10wermost, which central curve is connected to the rim II on each side by means of smooth parabolic and arcuate surfaces, the exact character of the curves in any given horizontal section Varying between a true parabola and a true circular arc according to the vertical location of the specific section. The reflector above described is particularly designed for use in the flood-lighting of relatively large areas when mounted at a considerable elevation above the ground and with its frontal plane substantially vertical, the median plane of the reflector containing the spiral segment being thus vertically positioned with its portion of greater radiants uppermost. The spiral section is employed to provide a more uniform and intense flood-lighting effect on the area to be illuminated than is possible of attainment through reflectors of symmetrical curvature in the vertical median plane, since the diverging area of the spiral curve produces an ever-changing incidence to the light rays impinging thereon and reflects said rays at angles productive of an exceptionally wide and long area of illumination on a surface perpendicular to the plane containing said spiral. The curves appearing in horizontal planes intersecting the reflector and in interconnecting relation between the circular outline of the frontal plane and the central spiral curve are smooth and continuous and hence are em-i pirically determined according to their vertical disposition relative to the assembly, it being obvious that the majority of the horizontal curves may be approximately parabolic. without presenting any undue distortion of the smooth and continuous nature, of a given curve, and that such curves will present a variation in their constants and mathematical characteristics according to their vertical location relative to the circular outline and spiral segment, the majority of such curves in the mid and lower portions of the reflector being generally parabolic while the horizontal curves of the upper portion in the reflector approach an arcuate character as the depth of the reflector decreases in proportion to the chord opening of the frontal outline. Formed on and interrupting the concavity above described, a plurality of ridges l2, in this instance twelve in number, radiate fanwise from a common point, located by intersection of the vertical median plane with the lower inner edge of the rim H, along and upwardly of the concavity described to uniform spacing of their upper ends on both sides of the vertical median plane along the junction of the concaved surfaces with the upper portion of the rim H, the wedge-shaped, vertically-disposed surfaces thus formed between adjacent ridges [2 being smoothly concaved from crest to crest of said ridges.

The improvement thus far described presents a complete and operative reflector which may be mounted in any suitable and desired manner in operative relation with a source of light. However, to obviate certain difliculties of installation and to provide a complete, operative assembly, a mounting extension I3 is suitably formed of metal, or other proper material, and provided with an open upper end shaped to receive the shell Ill and support the latter in vertical position, said extension and shell being rigidly secured in proper interrelation by means of screws (not shown) or any other suitable fastening means or devices. The extension I3 is formed with aligned, laterally-extending, cylindrical ears M which are adapted to be received in and held by suitable clamps (not shown), thus mounting the assembly for adjustment of the reflector shell through a vertical arc. A transverse web 15 is formed in the central lower portion of the extension 13 and serves as a support for an electric light socket l1 thus positioned within said extension beneath the shell In, said socket aligning with a hole I 6 .formed in the lower portion of said shell l0, through which hole an electric light bulb I8 may be inserted for operative engagement with the socket I1, the said bulb being thus positioned and held in proper relation with the reflecting surfaces of said shell, adjusting means l9 preferably being provided between the socket I! and web IE to facilitate proper positioning of the light source. Connection between the socket l1 and a source of electrical energy may be had by suitable insulated conductors, indicated at 20, which enter the extension l3 through one or the other of the ears M. A removable .and replaceable housing member Zl is preferably provided on the lower portion of the extension l3 in position to provide access to the base of the socket I! and connections therewith, the said extension l3, housing 2| and exterior of the shell l0 preferably being so shaped and finished as to interfit in a close approximation of a shell, as is clearly illustrated in Figure 2.

In the operation of the improvement shown and described, the socket H is so adjusted as to position the light source immediately in front of the reflectorrvertex and well within the concavity limited by the surface plane of the rim H, thus placing the lightsource between the reflector surface and the centers of any circular arcs or the foci of any parabolic arcs which may be found in the reflector surface apart from the narrow wedge-shaped surfaces between the ridges l2, and said light source is, in respect of said wedge-shaped surfaces, farther removed from the reflecting surfaces than are the centers or foci of said wedge-shaped areas, so that, the light source being as it were out of focus, no concentration of parallel or converging rays is possible from the reflector and the light projected therefrom is substantially free from glare. The main reflecting surface of the shell l0 projects a soft, diffused light throughout a relatively wide vertical and horizontal spread and the grouped, wedge-shaped reflecting surfaces project rays in every direction through the beam deriving from the main surface, said rays intersecting other rays in an infinity of points having .no possible common locus and effectively eliminating shadows, streaks and areas of weak illumination in the field deriving from the main surface. The illumination thus produced is particularly well adapted for flood-lighting purposes and is exceptionally efiicient in that the freedom from dark spots and weak areas permits adequate illumination with lights of relatively low energy consumption.

Since many variations and modifications of the specific form, construction and arrangement of the elements shown and described may be .had without departing from the spirit of my invention, I wish to be understood as being limited solely by the scope, of the appended claims rather than by any details of the illustrative showing and foregoing description.

I claim as my invention- 1. In a shell-like reflector having a frontal plane, a reflecting surface concaved rearwardly of said frontal plane, said surface being defined by a circular outline at its marginal intersection with said frontal plane, a central vertical strip in the central vertical plane perpendicular to said frontal plane conforming in outline with a segment of a mathematical spiral, and said spiraljoined to said circular outline by concaved areas such that every horizontal section thereof is a generally smooth curve intersecting said spiral and symmetrical to the plane containing said spiral, said reflector having a total depth not exceeding one half the diameter of its frontal opening.

2. In a concaved, shell-like reflector having a frontal plane, a reflecting surface concaved rearwardly of said frontal plane, said surface being defined by a circular outline at its marginal intersection with said frontal plane, a central vertical strip in the central vertical plane perpendicular to said frontal plane conforming in curvature with a segment of a mathematical spiral disposed with its axis parallel with, forwardly of and below the centerof the circular outline in .said frontal plane, and. said spiral joined to said circular outline by concaved areas such that every horizontal section thereof is a generally smooth curve intersecting said spiral and symmetrical to the plane containing said spiral, said reflector having a total depth not exceeding one half the diameter of its frontal opening.

3. In a concaved, shell-like reflector having a frontal plane, a principal reflecting surface concaved rearwardly of said frontal plane, said surface being defined by a circular outline at its marginal intersection with said frontal plane, a central "vertical strip in the central vertical plane perpendicular to said frontal plane conforming in outline with a segment of a mathematical spiral, and said spiral joined to said circular outline by concaved areas such that every horizontal section thereof is a generally smooth curve intersecting said spiral and symmetrical to the plane containing said spiral, and supplementary reflecting surfaces formed on said principal surface as smoothly concaved areas between and interconnecting ridges traversing said principal surface along lines marking the intersections of planes perpendicular to said frontal plane and diverging upwardly from the lower intersection of said spiral curve with said marginal outline with said principal surface, said 5 principal reflecting surface having a total depth not exceeding one half the diameter of its frontal opening.

LOUIS A. BEAN.

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