US3324290A - Lighting fixtures - Google Patents

Description

June 6, 1967 M. L. LASKER LIGHTING FIXTURES Sheets-Sheet 1 Filed Dec. 21,, 1964 FIEZ INVENTOR. MARTHJ L. LASKER AT TORN RY June 6, 1967 M. LASKER LIGHTING FIXTURES 5 Sheets-Sheet 3 Filed Dec. 21, 1964 EH WA v 3 5 o I. Jw E W M W F Av M E w B United States Patent 3,324,290 LIGHTING FIXTURES Martin L. Lasker, Metuchen, N.J., assignor to Moldcast Manufacturing Company, Newark, N.J., a corporation of New Jersey Filed Dec. 21, 1954, Ser. No. 419,715 21 Claims. (Cl. 240-112) The invention relates to lighting fixtures of the illurninated sign type and is more particularly directed to 1mprovements in such fixtures wherein the light source or sources are in off-center position.

An object of the invention is to provide a lighting fixture or sign which furnishes uniform distribution of light or even illumination though the light sources are in offcenter position.

Another object of the invention is to provide a sign having an off-center light source which is highly compact and extremely slim considering the quality of uniform light distribution furnished by the device.

A further object of the invention is to provide an offcenter light source type of sign which is so thinly constructed that the need for costly recessing in a wall for the mounting of the device may be eliminated.

Still another object of the invention is to provide a sign of the type under consideration which is constructed so that all the hardware required to permit access to the interior of the sign is contained within the sign to thereby furnish an exterior which is unbroken by projecting parts which would disrupt the uniform contour of the sign.

Still a further object of the invention is to provide signs of the type under consideration which have a single or common housing permitting the assembly therewith of different components to furnish either a single or double faced sign, and various mount means for supporting the sign, thereby affording the minimal inventory of components and economy of manufacture.

Still another object of the invention is to provide a lighting fixture of the type under consideration wherein the housing member of the thin compact assembly is further formed for assembly with a down-lighting memher, the light source for which is the same as the light source for the information provided at one or both sides of the fixture.

Still a further object of the invention is to provide a lighting fixture of the type under consideration which is constructed to prevent undesirable edge lighting, to prevent light leakage and to prevent injury to components of the fixture which may be affected by the heat generated by the light sources.

These, and other objects and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the drawings illustrating several preferred embodiments of the invention, in which:

FIG. 1 is a top plan view of a lighting fixture made in accordance with one embodiment of the invention, the frame member and light-transmitting panel components of the fixture being broken away to expose the back plate and interior of the housing, this view also omitting the wiring for clarity in illustration;

FIG. 2 is an enlarged horizontal, cross-sectional view taken approximately in the plane of line 2-2 of FIG. 1, this view being broken to the right of the center of the symmetrical fixture to permit the enlarged scale showing;

FIG. 3 is an enlarged, horizontal cross-sectional View taken approximately in the plane of line 33 of FIG. 1;

FIG. 4 is an enlarged, vertical cross-sectional view taken approximately in the plane of line 4-4 of FIG. 1;

FIG. 5 is an enlarged, vertical cross-sectional view taken approximately in the plane of line 55 of FIG. 1;

FIG. 6 is a rear view of the frame member and as sociated light-transmitting panel of the sign shown in FIGS. 1-5, the light-transmitting panel being partly broken away;

FIG. 7 is an enlarged, horizontal cross-sectional View taken approximately in the plane of line 77 of FIG. 6;

FIG. 8 is a detailed view of the means for separably connecting the frame member and its associated lighttransmitting panel to the signs housing;

FIG. 9 is a partial top plan view of the housing and the associated portion thereof which cooperates with means provided by the frame member for separable connection of the frame member to the housing;

FIG. 10 is a view similar to FIG. 2 but showing another or double faced sign embodiment of the invention;

FIG. 11 is a circuit diagram showing a preferred circuit for furnishing current to the lamps in both embodiments of the invention illustrated in FIGS. 1-9 and FIG. 10;

FIGS. 12-14 illustrate different forms of mountings which may be employed with the lighting fixtures of the invention; and

FIG. 15 is a front view showing another form of frame member which may be employed in the previously illustrated forms of the invention.

Referring to the drawings, a lighting fixture made in accordance with the invention generally, comprises a substantially rectangular housing A which is open to the front and rear sides thereof and a door or frame member B fitted to cover a side of the housing. The housing is defined by top, bottom and end walls. The frame member has a width and height substantially equal to such dimensions of the housing. The frame member has an opening therethrough in the form of a stencil face, or a rectangular opening for the viewing of the desired printed information printed on a transparent sheet. A pair of sockets, each designated C, are supported within the housing, and are each adapted to receive a lamp to extend in an area adjacent each of the housings end walls, or in extreme off-center position. A light-transmitting panel D is supported on the rear face of the frame member B to extend across the frame members opening or openings. The light-transmitting panel is substantially rectangular and made of a translucent material. The panel possesses a selected wall thickness to furnish even or uniform illumination. This is accomplished by making the panel so that it decreases in thickness from its side edges in the vicinity of the lamps to its center, thereby providing graduated decreasing opacity from the side edges toward the remote center of the panel. Means E is provided at each of the panels lamp adjacent edges to prevent edge lighting.

Where a single face sign is desired, the opposite side of the housing is closed off with an opaque back plate. Where a double faced side is desired, the opposite side of the housing is fitted with a second frame member and an associated light-transmitting panel. In the preferred form of the invention, shielding means F is provided intermediate the panels side edges and the light sources to absorb heat and to further prevent the leakage of light from the sign or fixture.

In greater detail, reference is made to FIGS. l7 which illustrate a single face sign providing the information that an EXIT is located in the proximity of the sign. It will be understood that the sign may provide any desired information to suit a particular need, such as indicating that stairs are located in the vicinity of the sign, etc. The housing A comprises top and bottom walls 20 and 22 respectively, which extend parallel to one another and are connected together by end walls 24 and 26. The lengths of the housing walls are selected so that the housing A is rectangular in outline. The top, bottom and end walls constitute the housing thereby leaving the sides thereof open and adapted for closure on one side by the frame member B and associated light-transmitting panel D, and on the opposite side by an opaque plate member G. The housings walls 20, 22, 24 and 26 each have the same dimension in depth or from front to back of the housing. In the preferred form of the invention, such dimension, designated a in FIGS. 3 and 4, is less than an inch, for example 0.937 inch. Where the lighting fixture is to serve as an EXIT sign, its width and height may be, for example, approximately 11.25 x 7.75 inches.

The housing may be of any rigid material such as a metal or a molded rigid plastic. While the housing may be made from strip metal stock bent to provide the desired rectangular contour, it is preferred that the housing be made by die casting. As will be hereinafter described, the housing serves a number of functions, and die casting permits expeditious and low-cost manufacture of the housing and its associated parts. The housing and its associated parts preferably are cast of an aluminum alloy. The housing may also be made by casting the same of a zinc alloy or by molding a suitable plastic material which furnishes a rigid framework.

As shown in FIG. 1, the housing is cast to provide integral means 28 to enable attachment of a bracket 30 for supporting the light socket C. The bracket support means 28 is cast in the form of a projection from the underside of the housings top wall 20. Such projection is drilled and tapped to receive a screw 32 so that the bracket 30 may be secured to the projection. Also, the projection is provided with a locating portion which extends through a mating cutout formed in the lamp socket bracket. An elongated lamp 34 is received within the socket C and projects downwardly in the area adjacent the housings end wall 24. As shown in FIG. 2, the same arrangement is provided for the mounting of a second lamp 34' within and on the opposite side of the housing where the lamp is positioned to extend in an area adjacent the housings side wall 26. Thus, the light sources are located within and at the extreme right and left sides of the housing, or in extreme off-center position.

In the form of the invention illustrated in FIGS. 1-7, the frame member B is in the form of a metal plate which is cut or stenciled within its borders to furnish the signs information. The frame member has the same rectangular outline and dimensions as the housing A, the periphery of the frame member coinciding with the outer periphery of the housing. As will subsequently appear, the frame member B is hingedly connected to the housing A, the frame member and housing being further provided with cooperative means for resilient-1y maintaining the frame member in closed engagement with the housing.

As shown in FIGS. 2-6, the frame member B is provided with an internal flange 36 spaced inwardly from the outer periphery of the frame member by an amount slightly greater than the thickness of the housings walls. Thus, when the frame member is in assembled relationship with the housing, the inner peripheral edge 38 of the frame member is in flush engagement with the adjoining peripheral edge 40 of the housings walls, the internal flange 36 closely abutting the internal sides of the walls at their forward edges. The thickness of the frame member does not add materially to the depth of the housing, the total thickness of the assembly preferably not exceeding 1.125 inches.

The frame member B is provided with means on its rear face for supporting the translucent, light-transmitting panel D. The frame member also is preferably made by die casting a suitable alloy such as aluminum or zinc, thereby permitting economical manufacture of the frame member and its associated parts. In the rectangular form of lighting fixture illustrated, the light-transmitting panel is also rectangular in outline being located behind the opening or stenciled information formed in the frame member.

As best shown in FIG. 6, the light -transmitting panel D is independently supported on the rear face of the frame member B. The frame member is provided with a pair of laterally spaced projections 42, 42' on the rear side thereof on the top within the internal flange 36. Also, the frame member is cast with a central pin 44, and is flanked by a pair of laterally spaced, horizontally extending supporting projections 46, 46' upon which the lower edge 48 of the panel D rests. The projections 42, 42' are drilled and tapped to respectively receive the threaded shanks of screws 50, 50, the heads of the screws extending through slots provided in clips 52, 52 which are used to bear against the rear side of the panel near the top edge thereof. An apertured circular disk 54 is positioned over the pin 44, the pin then being headed over to secure the assembly of the panel D with the frame member B. Lateral shifting of the light-transmitting panel on the frame member is prevented by a pair of side stop clips 56, 56' which are secured to studs 58, 58' cast to extend from the rear face of the frame member. These projecting studs are drilled and tapped to permit screws 60, 60 to be extended through the stop clips and into the studs. The frame member B and light-transmitting panel D mounted thereon constitute a separate sub-assembly.

The light-transmitting panel D preferably is made from a thermoplastic resin composition to which there is added suitable pigments or coloring agents to furnish translucency. The panel is preferably made by extruding a polystyrene compound. Other examples of materials which may be used to form the panel are methyl methacrylate, cellulose acetate-butyrate and glass. The translucent, light-transmitting panel is made so that the opacity thereof decreases (light-transmittance increases) from its side edges, designated 62, 62', where such edges are in the vicinity of the light sources or lamps 34, 34', toward the center of the panel. This is accomplished by making the panel to have its thickest cross-section at the side edges 62, 62 and then gradually reduced in thickness to its thinnest cross-section at the panels central or median line, designated 64, which is the area of the panel at the greatest distance from the light sources. This gradation in thickness or cross-section of the panel is illustrated in FIG. 2 and is also shown in FIG. 7. The decreasing opacity, working in inverse relationship to the increasing distance from the light sources acts to even out the brightness or illumination on the panel from the light sources.

In order to overcome the undesirable effect of edge lighting, and yet allow direct light to strike the panel D for transmittal therethrough, means E is provided at each of the panels side edges for this purpose. Preferably, and as illustrated, this is accomplished by molding the panel with a pair of ribs 66, 66 each of which extends rearwardly of the panel at the respective side edges 62, 62'. As shown in FIGS. 2, 3 and 7, ribs 66, 66', which extend the full height of the panel D, are each substantially triangular-shaped in cross-section and are further respectively provided with upstanding fins 68, 68. The increased thickness provided by the rib at each side edge of the panel further adds to these thickened areas to further increase the opacity or resistance to the passage of light through such areas. Laterally or edge-wise, the base of the rib is more opaque than at the top or apex including the fin 68. Each rib is so juxtaposed with respect to its respective adjoining lamp that it would cast a shadow on the portions of the panel inward of the ribs, the deeper shadow of the base falling at the side edges of the panel and the lesser shadow, where the apices are located, falling toward the center area of the panel.

To eliminate any varying shadow that may be cast by the ribs and to insure that edge lighting of the panel will be prevented, the side edges 62, 62' of the translucent panel, including the rearwardly projecting ribs 66, 66 and their respective upstanding fins 68, 68', are made completely opaque to the passage of light. By making the outer edges of the respective ribs opaque, any shadow which may result is phased out uniformly toward the center of the panel. Light coming directly from the light sources and reflected by the back plate, as will hereinafter be described, serves to even out the illumination of the panel. This is preferably accomplished by cementing a suitable material such as metalized mylar foil to the panels side edges. Such light-blocking material, designated 70, 70 for the respective edges, faces the lamps 34, 34', and furnishes a reflecting surface acting to baflie the light and to reflect heat. The desired characteristics of opaqueness and a reflecting surface at the panels side edges may also be accomplished by painting the edges, including the side of each rib facing the light source, with a suitable light and heat reflecting composition such as an aluminum paint. The height of the ribs 66, 66' and their respective fins 68, 68 is selected so that together with the light and heat blocking means '70, 76, direct light from the lamps 34, 34' is prevented from striking the side edges of the panel.

Another function of the panel ribs 66, 66', and their associated light-blocking means 70, 7t), is to permit the close proximity of the light sources and the illuminated panel. The coverings or coatings 70, 70' are of a material which is highly reflective to the infrared and ultraviolet rays emanating from the light sources. Such structure of the panels side edges protects the panel from these rays which at very short distances are intense enough to cause damage to the structure and pigmentation of the panel. As a result, close positioning of the light sources and the panel is achieved for a highly compact design.

The described structure of the panel affording the even illumination of the panel from the off-center light sources, together with the structure of the panel which acts to prevent edge lighting, affords uniform light distribution through the panel, and, of course, through the stencil openings in the frame member B. In order that attention may be more forcibly directed to the sign and the information thereon, the information may have imparted thereto a suitable eye-arresting color such as green or red. For this purpose, a plastic sheet 72 (FIG. 7) of the desired color may be interposed between the panel D and the frame member B upon which the panel is supported.

In accordance with the preferred form of the invention, shielding means F associated with the frame member B are provided to prevent leakage of light in the event the panel D may be spaced even slightly at its edges from the adjoining surface of the frame member B. Also, such means possesses the added function of serving as a heatsink to absorb heat from the adjacent lamp. As shown in FIGS. 2, 3 and 7, the metal frame member D is provided with a pair of vertically extending shielding ribs 74, 74' which when the frame member is assembled with the housing are each positioned intermediate a lamp and a side edge of the panel D. The ribs 74, 74' are preferably cast as an integral part of the frame member and extend lengthwise a distance substantially equal to the length of the lamp adjacent which they are each situated. These heat-sink and light leakage preventive ribs need only be of a height substantially equal to the edge of the panel without the panels added thickness furnished by its ribs 66, 66. As shown in FIGS. 2, 3 and 7, the frame member ribs are also substantially triangular in cross-section.

Where, as in the showing of FIGS. 1-7, the lighting fixture is of the single face type, the rear side of the housing A is closed off by an opaque or metal plate G. The plate G has a width and height so that it fits closely within the housing on the inner periphery provided by the housings top, bottom and end walls. As shown in FIGS. 2 and 4, the connection of the back plate G with the housing does not add to the thickness of the fixture. The back plate is secured in fixed position within the housing by two pairs of screws, one pair passing through openings in the back plate and threaded into tapped holes formed in a pair of laterally spaced projections 76 cast to extend from the underside of the housings top wall 20, as shown in FIG. 4. As shown in FIGS. 1 and 3,

the connection is made at the bottom of the plate by a pair of screws extended into tapped holes formed in spaced projections 78 cast to extend up from the housings bottom wall 22.

The back plate G is preferably designed so that its inner face is light absorbing at the areas in the vicinity of the lamps 34, 34' and light reflecting for the remainder of the plate, or in the areas spaced from the light sources. Thus, light from the lamps hitting those areas of the back plate which would normally be reflected to the edges of the light-transmitting panel D is absorbed, while light which is directed further to the center of the back plate is allowed to be reflected to the center of the lighttransmitting panel. Also, the light absorbing areas are shaped to compensate for certain relatively dark areas at the top and bottom of the ends of the light-transmitting panel due to the filament in each of the lamps being shorter in length than the height of the surface which it is lighting.

The foregoing characteristics of the back plate are preferably provided by making the back plate of steel and imparting a lightreflecting surface to its inner side 89 as by vacuum metalizing. The light-reflecting surface may also be obtained by plating the steel plate with a bright, light-reflecting finish such as chromium, or by bright dipping. The inner surface of the plate is provided with light absorbent areas 82, 82 adjacent each lamp by maskmg the remaining area of the plate and sprayfng with a dull finish paint. Such light absorbent areas may also be made by adhering suitably coated paper to the plate. The light absorbent areas 82, 82' preferably have the configuration a illustrated in FIG. 1; that is, these areas are triangular in shape, the apex of the triangle being spaced from the lamp or light source, the base of the triangle being overlain by the bulb of the lamp. As a result, a light distribution pattern directed to the panel D is obtained as indicated by the arrowed lines of FIG. 2 to furnish maximum and uniform light distribution devoid of hot spots.

For added transmission of light through the translucent panel D, it is preferred to take advantage of the necessity to mount the Wires leading to the lamp sockets C. A pair of Wire mounting members 84 are each located adjacent a lamp bracket 30, and are fashioned to furnish reflectors. As shown in FIGS. 1 and 4, each wire mounting member 84 is in the form of a generally U-shaped member the base of which is depressed into a V shape. The arms of each mounting member have openings therethrough permitting screws 88, 88' to be extended through such openings and to be received in tapped holes formed on opposite sides of the projection 76. The screws 88 serve both to secure the back plate G as well as one side of a wire mounting member to the housing. The screws 88 secure the opposite side of each Wire mounting member to the projection 76 and the housing. The wire mounting members 84 are made of metal and plated or vacuum metalized to furnish reflecting surfaces thereby acting as small reflectors which direct light to the relatively dark area of the panel D to additionally even out the brightness level on the panel.

As shown in FIG. 1, the back plate G is provided with a central aperture 0 leading to the rear of the fixture through which the wires are passed for connection to a junction box and a source of power. A preferred form of circuitry for the lighting fixture is illustrated in FIG. 11. A diode 92 is placed in series with the two lamps 34, 34' which are connected in parallel. The diode converts alternating current to half-wave direct current thereby affording 60 to of the available wattage, such rectified wattage affording approximately eight years of lamp life. The lamps are preferably 25W T 6 /2 DC/ 1F lamps, which are commercially available. As shown in the circuit diagram, a pair of conductors 94, 94' respectively connected to each of the lamp sockets C is connected to a lead 96 extending from the diode. The second lead from the diode 96 is connected to one side of the power source. A second pair of conductors 98, 98' respectively connected to the two lamp sockets C are connected into the other conductor to the power source. As shown in FIG. 1, the diode 92 is supported Within one of the reflectors 84 and the connection of the diode lead 96 to the conductors 94, 94' from the lamp sockets may be positioned within the other reflector.

The housing is further made to support a downlighting lens 104) which uses the same light sources furnishing the light transmitted through the panel D. For this purpose, and as shown in FIGS. 1 and 4, the bottom wall 22 of the housing is provided with a longitudinally extending opening 102 within which the elongated lens member 100 is positioned. The down-lighting member is made of any suitable transparent material, a molded styrene composition being preferred. In order to furnish as strong a light as possible, the under or exposed surface of the lens is provided with longitudinally extending, transversely spaced ribs to furnish a lens effect. The down-lighting lens member is made with longitudinally extending side flanges 104, 104' which rest on the adjoining surfaces of a platform cast on the bottom wall 22 to surround the opening 102, thereby preventing the down-lighting member from dropping out of the housing and locating the exposed surface of the down-lighting member substantially flush with the outer face of the bottom wall. The down-lighting member is held securely in the cutout 102 by a pair of holding clips 106 each having an arm which bears on the top side of the lens member near an edge thereof. The holding clips are secured to one side of the upstanding projections 78, the opposite sides of which serve to secure the back plate G to the housing as previously described. In keeping with the symmetry of the device, there are of course a pair of holding clips each secured to the laterally spaced projections formed on the bottom wall 22 of the housing to maintain the down-lighting member securely within the cutout 102. As shown in FIG. 1, the clips are secured to the studs by screws 110 extended through openings in the clips and into tapped holes formed in the projections.

The housing and the frame member are provided with cooperative means for hingedly connecting the frame member to the housing to permit access to the interior of the housing, as when it is desired to replace a lamp. As shown in FIGS. 1, 3, 4 and 5, the housing is symmetrically provided at each side thereof, near the bottom wall 22, with inwardly projecting circular pins 112. Each pin may be grooved at its front end to receive an arm of the clip 106 and prevent its rotation. The pins are centrally located with respect to the depth of the bottom wall 22 and each projects outwardly from a hinging portion 114 intermediate the pin and its respective end wall. As shown in FIG. 5, each hinging portion 114 projects transversely so that its rear edge serves as stop means for the back plate G, while its forward edge provides a bearing 116 over which a cooperating nose portion 118 formed to project from the frame member may pivot when opening or closing the frame member. The frame member is resiliently connected to the housing by spring means 120 associated with each pin 112. As best shown in FIGS. 3 and 5, the turns of the spring encircle the pin and the ends of the spring are extended and bent at 122, 122 to be hooked about an eye 124 pierced and formed to extend inwardly from the back plate G and an eye 126 cast to extend inwardly from the frame member B.

In order to facilitate rotation of the frame member B and its associated light-transmitting panel D about the hinge means provided near each end at the bottom of the assembly, the frame member is provided at the top with a pair of laterally spaced grooves 128, 128 (FIG. 6) to enable one to grasp the edge of the frame member and rotate it back from the housing about the hinge means. To maintain the frame member and its associated lighttransmitting panel in closed position on the housing, the housing is provided with catch means 130 cast on the underside of the housings top wall 20, such means taking the form of a longitudinally extending projection. The frame member is cooperatively provided with a leaf spring 132 bent to the configuration shown in FIG. 8 so that the spring may snap over the projection 130 when the frame member B is closed upon the housing. The spring has its inner end attached to the frame member by a screw 134 extended through an opening in the end of the spring and into a stud 136 cast to extend from the rear face of the frame member. As shown in FIG. 9, the projection 139 of the connection means is preferably provided with a second portion 130 offset therefrom so that the same housing provides catch means for a second frame when the housing is used for a double-face sign.

FIG. 10 illustrates a double-face sign form of the invention. The housing A, its associated parts, the frame member B, its associated light-transmitting panel D, and the relationship of these components are the same as hereinbefore described. Instead of an opaque back plate G however, the opposite side of the housing is provided with a second frame member and associated light-transmitting panel, designated B and D. The second frame member is hinged to the housing in the same manner as hereinbefore described; also, the down-lighting member 100 may be provided in the bottom wall of the housing in this form of the invention. The thickness of the doubleface fixture is increased only to the extent of the thickness of the second frame member.

Regarding the light-transmitting characteristics of the panel supported on the frame member, or the two panels in the case of a double-face sign, the material of the panel is such that its translucence or semi-opacity is due to partial reflectance of light rather than partial absorption of light. The panel being translucent, its inner surface is semi-specular in character; that is, its reflective nature is such that there is a tendency for the light rays reflected from the panel's surface to be broken up or diffused. By virtue of the graduated thickness of the panel, this diffusion is controlled so that the average angle of reflectivity is approximately the same as the angle of incidence. Thus, the light from the sources or lamps strikes the adjacent ends of the panel at a highly oblique angle. Since reflectivity from a semi-reflectant surface increases as the angle of incidence decreases, a substantial amount of the light striking the ends of the panel is reflected toward the center of the unit. The partial diffusion of the light causes an increase of the angle of reflectivity for some rays of light. In the case of a double-face sign, these light rays travel to the opposing panel and strike it at a greater angle which permits the transmission of light through such opposing panel. The reflection of light striking the areas of the panel adjacent the light sources and the transmission of a major proportion of this light bythe center of the panel acts to even out the brightness or illumination across the panel.

The same housing as described may be used for any desired form of mounting for the sign without changing the structure of the housing or the structure of the associated frame member or members, associated lighttransmitting panel or panels, or opaque back plate. Instead of the flat wall mounting for a sign, as shown in FIGS. 1 to 7, the fixture may be provided with an end mount 138 as shown in FIGS. 10 and 12; or a ceiling mount 140 as shown in FIG. 13; or a pendant mount 142 as shown in FIG. 14. It is only necessary that the selected mount be secured to the top or end wall of the housing. This is accomplished by simply providing tapped holes in the wall of the housing with an aperture for the passage of the wires to the sockets and connecting the mount to the housing with screws. Also, instead of the opening in the frame being stencil cut, the frame member B may be provided with a continuous through opening 144 as shown in FIG. 15, whereby the desired information directing attention to the fixture may be printed upon a plastic sheet overlaying the front surface of the lighttransmitting panel.

While a light-transmitting panel of graduated thickness as described is adequate to furnish uniform and bright light distribution with the off-center lighting sources in a fixture as described, it is within the scope of the invention to position a film of graded opacity in fiat contact with the translucent, light-transmitting panel to further heighten the effect afforded by the graduated thickness from side edges to center.

It is believed that the advantages and improved results of the invention will be apparent from the foregoing description of a preferred embodiment of the invention. Various changes and modifications may be made without departing from the spirit and scope of the invention as sought to be defined in the following claims.

I claim:

1. In a lighting fixture, a substantially rectangular housing having top, bottom and end walls andopen to the sides thereof, a pair of sockets supported within said housing each adapted to receive a lamp to extend in an area adjacent each of said end walls, a frame member having an opening therethrough fitted to cover one of said sides, a substantially rectangular, translucent, light-transmitting panel supported on the rear face of said frame member extending across the frame members opening, the side edges of the panel being positioned adjacent the lamp areas, said panel decreasing in thickness from its side edges to the center to provide graduated, decreasing opacity from the side edges toward the center of the panel, and means provided by the panel at each of the panels side edges to prevent edge lighting.

2. In a lighting fixture, a substantially rectangular housing having top, bottom and end walls and open to the sides thereof, a pair of sockets supported within said housing each adapted to receive a lamp to extend in an area adjacent each of said end walls, a frame member having an opening therethrough fitted to cover one of said sides, a substantially rectangular, translucent, light transmitting panel supported on the rear face of said frame member extending across the frame members opening, the side edges of the panel being positioned adjacent the lamp areas, said panel decreasing in thickness from its side edges to the center to provide graduated, decreasing opacity from the side edges toward the center of the panel, means provided by the panel at each of the panels side edges to prevent edge lighting, and shielding means intermediate each lamp area and each side edge of the panel for absorbing heat and preventing the leakage of light.

3. In a lighting fixture as set forth in claim 2, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a light-blocking material.

4. In a lighting fixture as set forth in claim 2, wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof.

5. In a lighting fixture as set forth in claim 2, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a light-blocking material; and wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof.

6. In a lighting fixture as set forth in claim 2, wherein the top wall of the housing has connected thereto a pair of laterally spaced wire mounting members the outer surfaces of which are reflectors.

7. In a lighting fixture as set forth in claim 2, wherein the housings bottom wall is provided with an opening within which is set a down-lighting lens member.

8. In a lighting fixture as set forth in claim 2, wherein the housing and the frame member are provided with cooperative means for resiliently hinging the frame member and its associated light-transmitting panel to the housmg.

9. In a lighting fixture as set forth in claim 2, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a light-blocking material; wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof; wherein the top wall of the housing has connected thereto a pair of laterally spaced wire mounting members the outer surfaces of which are reflectors; wherein the housings bottom wall is provided with an opening within which is set a down-lighting lens member; and wherein the housing and the frame member are provided with cooperative means for resiliently hinging the frame member and its associated light-transmitting panel to the housing.

10. A lighting fixture comprising a substantially rectangular housing having top, bottom and end walls and open to the sides thereof, a pair of sockets supported within said housing each adapted to receive a lamp to extend in an area adjacent each of said end walls, a frame member having an opening therethrough fitted to cover one of said sides, a substantially rectangular, translucent, light-transmitting panel supported on the rear face of said frame member extending across the frame mem-bers opening, the side edges of the panel being positioned adjacent the lamp areas, said panel decreasing in thickness from its side edges to the center to provide graduated, decreasing opacity from the side edges toward the center of the panel, means at each of the panels side edges to prevent edge lighting, shielding means intermediate each lamp area and each side edge of the panel for absorbing heat and preventing the leakage of light, and an opaque plate covering the opposite side of the housing, said plate having an inner light-reflecting surface except in the lamp areas where the inner surface of the plate is light-absorbent.

11. A lighting fixture as set forth in claim 10, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a light-blocking material; and wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof.

12. A lighting fixture as set forth in claim 10, wherein the top wall of the housing has connected thereto a pair of laterally spaced wire mounting members the outer surface-s of which are reflectors.

13. A lighting fixture as set forth in claim 10, wherein the housings bottom wall is provided with an opening within which is set a down-lighting lens member.

14. A lighting fixture as set forth in claim 10, wherein the housing and the frame member are provided with cooperative means for resiliently hinging the frame member and its associated light-transmitting panel to the housing.

15. A lighting fixture as set forth in claim 10, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a light-blocking material; wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof; wherein the top wall of the housing has connected thereto a pair of laterally spaced wire mounting members the outer surfaces of which are reflectors; wherein the housings bottom wall is provided with an opening within which is set a down-lighting lens member; and wherein the housing and the frame member are provided with cooperative means for resiliently hinging the frame member and its associated light-transmitting panel to the housing.

16. A lighting fixture comprising a substantially rectangular housing having top, bottom and end walls and open to the sides thereof, a pair of light sockets supported within said housing each adapted to receive a lamp to extend in an area adjacent each of said end walls, a pair of frame members each having an opening therethrough fitted to cover each of said sides of the housing, a substantially rectangular, translucent, light-transmitting panel supported on the rear face of each of said frame members extending across the frame members openings, the side edges of each panel being positioned adjacent the lamp areas, each of said panels decreasing in thickness from its side edges to the center to provide graduated, decreasing opacity from the side edges toward the center of the panel, means provided by the panel at each of the panels side edges to prevent edge lighting, and shielding means intermediate each lamp area and each side edge of a panel for absorbing heat and preventing the leakage of light.

17. A lighting fixture as set forth in claim 16, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a light-blocking material; and wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof.

18. A lighting fixture as set forth in claim 16, wherein the top wall of the housing has connected thereto a pair of laterally spaced wire mounting members the outer surfaces of which are reflectors.

19. A lighting fixture as set forth in claim 16, wherein the housings bottom wall is provided with an opening within which is set a down-lighting lens member.

20. A lighting fixture as set forth in claim 16, wherein the housing and the frame members are provided with cooperative means for resiliently hinging the frame members to the housing.

21. A lighting fixture as set forth in claim 16, wherein the means at each of the panels side edges to prevent edge lighting comprises a rib formed integrally with the panel to extend rearwardly thereof, the side edge of the panel including the rib being covered with a lightblocking material; wherein the shielding means comprises a rib formed integrally with the frame member extending from the rear face thereof; wherein the top wall of the housing has connected thereto a pair of laterally spaced wire mounting members the outer surfaces of which are reflectors; wherein the housings bottom wall is provided with an opening within which is set a down-lighting lens member; and wherein the housing and the frame members are provided with cooperative means for resiliently hinging the frame members to the housing,

References Cited UNITED STATES PATENTS 1,831,181 11/1931 Koster 2401l.2 1,912,487 6/ 1933 Matera 240-4135 2,278,951 4/ 1942 Smith et a1 2402.1 2,677,909 5/1954 Heydenryk 40152.2 2,728,849 12/1955 Beber et al. 240-147 X 3,029,334 4/1962 Anderson et al 2401 3,136,083 6/1964 Guth 24011.4

FOREIGN PATENTS 887,326 8/ 1943 France.

1,020,453 11/ 1952 France.

NORTON ANSI-IER, Primary Examiner.

R. M. SHEER, Assistant Examiner.

Claims (1)

1. IN A LIGHTING FIXTURE, A SUBSTANTIALLY RECTANGULAR HOUSING HAVING TOP, BOTTOM AND END WALLS AND OPEN TO THE SIDES THEREOF, A PAIR OF SOCKETS SUPPORTED WITHIN SAID HOUSING EACH ADAPTED TO RECEIVE A LAMP TO EXTEND IN AN AREA ADJACENT EACH OF SAID END WALLS, A FRAME MEMBER HAVING AN OPENING THERETHROUGH FITTED TO COVER ONE OF SAID SIDES, A SUBSTANTIALLY RECTANGULAR, TRANSLUCENT, LIGHT-TRANSMITTING PANEL SUPPORTED ON THE REAR FACE OF SAID FRAME MEMBER EXTENDING ACROSS THE FRAME MEMBER''S OPENING, THE SIDE EDGES OF THE PANEL BEING POSITIONED ADJACENT THE LAMP AREAS, SAID PANEL DECREASING IN THICKNESS FROM ITS SIDE EDGES TO THE CENTER TO PROVIDE GRADUATED, DECREASING OPACITY FROM THE SIDE EDGES TOWARD THE CENTER OF THE PANEL, AND MEANS PROVIDED BY THE PANEL AT EACH OF THE PANEL''S SIDE EDGES TO PREVENT EDGE LIGHTING.

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