US3549879A - Lighting fixture - Google Patents

Description

United States Patent [72] Inventor Carl X. Meyer Saint Louis, Mo. [21] Appl. No. 675,105 [22] Filed Oct. 13, I967 [45] Patented Dec. 22,1970 [73] Assignee Emerson Electric Co.

St. Louis County, Mo. a corporation of Missouri [54] LIGHTING FIXTURE 12 Claims, 15 Drawing Figs.

[52] U.S.Cl. 240/147, 240/78, 240/51.1 1, 240/ 106 [51] Int. Cl F2lv 17/00 [50] Field ofSearch.... 240/147, 78, 78CF, 78LD, 78LD7,51.11,47, 106

[56] References Cited UNITED STATES PATENTS 2,368,810 2/1945 Donnelly 240/51.11 2,619,584 11/1952 Hathaway... 240/51.1l 3,093,322 6/1963 Boutelle 240/78 3,239,661 3/1966 Wince 240/78X 3,251,987 5/1966 Wince 240/5l.l1X FOREIGN PATENTS 951 159 3/1964 Great Britain 240/78 Primary Examiner-.1ohn M. Horan Assistant Examiner-Monroe l-l. Hayes Attorney-Philip B. Polster ABSTRACT: A lighting fixture for mounting on the ceiling as a plastic light-transmitting enclosure which is held in place by a releasable latch member. The base member upon which the plastic enclosure is supported has downwardly convergent sidewalls and the plastic enclosure member has an inwardly extending flange extending about its upper periphery. The flange has a prismatic surface for directing light about the base member to eliminate shadows. At each comer of the base member a tin extends from the corner of the plastic enclosure member to the corner of the base member to give the appearance of a rectangular fixture. The latch member comprises resiliently mounted hook members mounted on opposite sides of the fixture and having a shoulder for supporting the plastic member.

PATENTEDDECZZISYB SHEET 3 OF 4 FIG ' new FIGJZ PATENTED UEE22 I976 549- 7 saw u or 4 v W Abram 6 1 ucnrrnc rrxT-Uns BACKGROUND OF THE INVENTION 7 This invention has particular but not exclusive application to fluorescent fixtures intended for mounting directly to the surface of a ceiling. Presently known surface fixtures having light transmitting enclosures of plastic material generally fall into one of two basic types,

One, long familiar to those experienced in the art, has become commonly-known as the plastic wrap-around type. The enclosure is usually supported by a fixture channel and is spaced away from the ceiling, creating a cavity or pocket along the fixture sides at the ceiling. While the pocket provides a clearance space to permit hinging the enclosure in servicing the fixture, it also frequentlycreates a shadow on the ceiling surface.

A second type of surface fluorescent fixture has a basic shallow boxlike configuration preferred-.bymany in the architectural profession for its simple, clean lines. Fixtures in this type may have plastic enclosure sidewalls which extend substantially to the ceiling line in order to achieve ceiling illumination. Others, of more substantial construction may have some metal framing along the fixture sides, which in itself creates a shadow, both on the ceiling and on the metal frame. I

For the most part, fluorescent fixtures of both basic types have required end members of the enclosure to be constructed entirely of metal or some other opaque material in order to conceal fluorescent lampholders which are themselves manufactured of opaque material. Some attempts have been made to incorporate light-transmitting plastic in portions of fixture ends below the line of lampholders. However, the need for making mechanical provision for through circuit wiring of units mounted end-to-end in continuous rows has precluded fully illuminated ends. For this reason, fluorescent fixtures, rectangular as well as square types, have, had a linear look, accentuated by basicdifferences in lengthwise vs. crosswise appearances.

One of the objects of this invention is to provide a lighting fixture in which the ends and sides have the same visual appear ance.

. ture which, when surface mounted, illuminates the ceiling to create a shadowless effect completely the fixture.

Still anotherobject of this invention is to provide a lighting fixture for surface or suspension mounting, in which a shadowless splay effect is provided completely around the periphery of the fixture. 7

Still another object of this invention is to provide such a lighting fixture for surface or suspension. mounting, in which individual units of the fixture may be connected end-to-end in continuous rows.

Still another object of this invention is to provide such a fixture in which the lens is easily removed or swung down for cleaning or relamping of the fixture without obvious retaining devices.

Other objects will become apparent to those skilled in the art in the light of the'following description and accompanying drawings.

around the periphery of SUMMARY or THE INVENTION In accordance with this invention, generally stated, a lighting fixture is provided with a metal lamp housing having downwardly convergently directed bounding walls defining a frame to be mounted on or adjacent to the ceiling. A lens panel enclosure is provided with an inturned lip along an upper edge, defining at its inner and outer edges a configurabounding walls. In the preferred embodiment, the bounding wall defines a rectangular frame, and right triangular fins at each comer project from each contiguous wall, with the base of each fin above a corner defined by meeting lips of the enclosure to give the illusion of perpendicularity of the bounding wall with respect'to the ceiling line.

The lens panel enclosure is so constructed as to direct light toward, through, and around the inturned lip. Preferably the enclosure includes a broad planar area with pyramidal or conical prisms, sidewalls with at least one prismatic surface, and a prismatic surface on the inturned lip.

In order to hold the enclosure in place and to permit its being removed or swung down, latches, preferably four in number, are mounted on the frame. In the preferred form, each of the latches has a lip-supporting shoulder spaced below the outer lower edge of the bounding wall to receive between the shoulder and the lower edge of the mounting wall a lip of the closure. The latch also has an outwardly upwardly opening hook on it spaced below the shoulder, and a spring part mounted on the frame, and arranged to bias the hook and shoulder outwardly, but to permit inboard movement with respect to the bounding wall of the frame; Stop means are provided on the frame to limit the outboard movement of the hook and shoulder parts of the latch.

BRIEF DESCRIPTION OF TI-IEDRAWINGS In the drawings FIG. I is a view in perspective of one illus trative embodiment of lighting fixture .ofthis invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1;

FIGS. 3, 4, and 5 are sectional views corresponding to the view shown in FIG. 2 but without a central wireway, showing steps in the removal or hinging down from the frame of the fixture of the enclosure;

FIG. 6 is a fragmentary detailed view in perspective of a latch member of this invention mounted on an inner wall of a lamp housing;

FIG. 7 is a fragmentary sectionalview of an end of the housing and enclosure of the illustrative embodiment of fixture shown in FIGS. 1-5; I

FIG. 8 is a view in rear elevation of the latch member shown in FIG. 6;

FIG. 9 is a bottom plan view of one corner of the lamp housing of the illustrative embodiment-of fixture shown in FIG. 1, showing one type of construction of fin';

FIG. 10 is a view in perspective of a winged fin of the type shown in FIG. 9 before incorporation into the frame;

FIG. 11 is a fragmentary longitudinal sectional view illustrating the path of representative light rays through the inturned end lip of the enclosure of the fixture shown in FIG. 1, part of the sectioning being omitted for clarity;

FIG. 12 is a fragmentary longitudinal sectional view show ing two fixtures of this invention butted in a continuous run;

FIG. 13 is a fragmentary longitudinal sectional view showing an end of another embodiment;

FIG. 14 is a view in perspective of .the embodiment of fixture of which FIG. 13 shows a portion of one end; and

FIG. 15 is a fragmentary transverse sectional view illustrating the path of representative light rays through the inturned side lips of the enclosure of both illustrative embodiments and, in principle of the inturned end lips of the enclosure of the embodiment shown in FIGS. 13 and 14, part of the sectioning being omitted for clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. l-12 ofthe drawing for one illustrative embodiment of fixture of this invention, reference numeral 1 indicates a fixture mounted on a ceiling 2. The fixture 1 includes a metal lamp housing 3, an enclosure 5, latches 6, and lamps 8, which are mounted in sockets 9, which are carried by the end walls of the housing 3 in a conventional manner.

I rectangular, with two long sides and two shorter ends. Side bounding walls 31 ;are integral with reflector walls 32 and a top 'wall 33. Bounding end walls 35 are integral with end reflector walls 36 which complete the reflector portion of the housing, and support lamp mounting sockets 9 on each end. 1 At each of the four corners of the housing, a fin 7 projects at .135" from the contiguous wall. In this embodiment, the fins 7 are made with integral wings 71, which are welded to the undersides of the bounding walls 31 and 35, shown in FIG. 3, to provide a convenient way of assembling the frame.

It can be seen that each of the bounding walls 31 slopes conver'gently downwardly to a lower outer edge 33 defined by the arris between the wall and a planar ledge 37 to the inner edge .of which is in turn defined by a stop rib 38. In respect of the slope of the wall, all of the walls 31 and 35 are identical. However, to accommodate the lamp mounting sockets in the embodiment shown, the end walls 35, except between the outboard edges of the lamp-mounting sockets and the corners where they meet the sidewalls 31, extend downwardly to the reflector end wall 36 are cut away to accommodate the lamp "mounting sockets. {The enclosure 5, of light transmitting material, preferably plastic, is, in the embodiment shown, rectangular, with prismatic bottom-wall 51 with a multiplicity of contiguous pyramidalprisms on its emergent surface, sidewalls 52 and end walls 53 both with lengthwise prisms along their inside surface and heightwise prisms along their outside surface, and an intumed lip 54, which extends around the entire periphery of the enclosure. In this embodiment, the lip has lengthwise prisms on its outside surface, and the lip is wider along the side walls 52 than it is along the end walls 53. Preferably the entire enclosure is molded in one piece. Ascan be seen particularly in FIG. 2, the lip 54 along the sidewalls 52 of the enclosure projects inboardly of the lower outer edge of the side-bounding walls 31, and extends outboardly of the edge 33 to approximately the same vertical line as the upper edge of the bounding walls 31. The inner edge of theflip 54 terminates short of the stop rib 38 to permit the upper edge of the lip 54 to seat against the ledge 37. At the ends, an upper inner edge of the lip 54 meets the sloping outer surface of the wall 35.

On both sides and ends, the intumed lip 54 projects outboard of the lower outer edge of the bounding wall, exposing the prismatic elements and permitting light from the lamps to illuminate the bounding wall surfaces and the ceiling area contiguous the fixture. This is illustrated particularly in FIG. ll, where representative light rays are shown being refracted and reflected to the desired areas. The optical explanation for the operation of r the prisms in the bottom wall 51 is set forth in some detail in McPhail US. Pat. No. 2,474,317. Interestingly, Mclhail dismisses the rays reflected or refracted back into the housing as being without importance except to be reflected again'toward the panel bottom wall. In the present device, these rays are utilized directly. It is to be understood that the light paths shown in FIG. 11 are schematic. The light striking the bounding wall, for example, will be diffused, and the light striking the external prisms in the sidewall may be spread in theplane perpendicular to the plane of the drawing.

The latch members 6 serve to retain the enclosure in closed position and to permit its removal or its being swung down from the frame to permit cleaning and relamping of the fixture. The latch members 6 of this embodiment include a mounting spring 60, mounted at one end on the inside surface hook part 63 includes a shoulder 65, so positioned and arranged that when it abuts the lower edgeof a stop rib 38, it is parallel to and substantially coextensive outwardly with the ledge 37 of the frame. The hook part 63 is completed by a recurved finger 67, an inside surface 68 of which forms a lipreceiving seat 66 and, extending to the outer edge of the shoulder 65, forms a cam surface 69. The hook part 63 is preferably made of a high strength, slick resilient-surfaced plastic, such as acetal resin (e.g. Dupont Delrin"), which is easily formed, durable, easy on die enclosure, slick-surfaced enough to permit easy sliding movement of the enclosure lip over the inclined surfaces of the hook part, and resilient enough to minimize vibration noise.

The latch members 6 are mounted a short distance inwardly from the ends of the frame, on both inner walls 32, two on each side, so that the enclosure can be swung either way.

The assembly of the frame is self evident. The wings 71 of the corner fins 7 serve as a convenient means of securing the ends of the frame to the side walls. The fins themselves extend flush with the meeting comers of the bounding walls 31 and 35 at the upper edge, to a point flush with the lower surface of the ledge 37, the outer edge of the fin being perpendicular to the plane of the ledge 37 and the other horizontal surfaces of the fixture, as shown in FIGS. 1-5.

Assuming that the enclosure is in mounted condition, as shown in FIGS. 1 and 2, it can be swung away or removed from the frame by the steps shown in FIGS. 3, 4, and 5. First it is merely pulled down by grasping the upper surface of the lip intermediate the length of the sides of the enclosure, which causes the spring part 60 to bend inboardly until the inner edge of the lip clears the outboard edge of the shoulder, when the enclosure will drop to the position shown in FIG. 3. The enclosure is now moved sideways, in either direction, pulling the hook members on one side, against the bias of springs 60, toward the other side, until the opposite lip clears the finger 67 of the hook, permitting that free side of the enclosure to be dropped down. It will be observed that the stop rib 38 limits the outboard movement of the hook parts on the side toward which the enclosure is shifted. If the free side of the enclosure is now merely permitted to drop, the other side of the enclosure will remain suspended by the hook part, lip 54 resting in the seat 66 of the hook part. If it is desired to remove the enclosure, it can simply be lifted from the seat.

In installing the enclosure, the opposite procedure is fol lowed. One of the lips is hooked into the seat, the other side of the enclosure is swung up and the enclosure is either shifted or merely pushed up to cam the hook part in until the enclosure reaches the position shown in FIG. 3. The enclosure is then pushed upward, the lip camming against the surface 69, forcing the hooks inboardly until the lip clears the edge of the shoulder, when the spring 60 will snap the shoulder under the lip, as shown in FIG. 2.

While, in the illustrations of this preferred embodiment, the

fins 7 are delineated to indicate their presence, in commercial application, they are painted the same color, ordinarily white, as the side and end bounding walls 31 and 35, and are practically indistinguishable at normal viewing distance, so that the frame gives the impression of being square, and square cornered. At the same time, since the entire enclosure, including the lip and side and end walls is made of light transmitting material, the side and end bounding walls of the frame are sloped convergently downwardly, and the prismatic lens provides a substantial amount of light to them, the lighted fixture creates a shadowless splay effect completely around the periphery of the fixture.

Even though the fixture of this invention has inwardly downwardly convergent bounding walls and presents substantially the same appearance from every angle, it is still capable of being mounted in line in end-to-end relation to other indentical fixtures with single through-circuit wiring. Referring particularly to FIGS. 2 and 12, a wireway fit) which is snapped to lips formed from edges of a cutout section of the top wall 33, is positioned between lamps 8 and runs the length of the fixture to receive ballast and electrical conductors. ln a through-circuit application, knockouts in the' end walls 35 are The fixture housings butt at the top and along the vertical edges'of the fins, and the telescoped bushing 81, as shown particularly in FIG. 12, is totally concealedfrom below.

Referring now to FIGS. 13 and [4 for another embodiment of fixture of this invention, which differsfrom the embodiment shown in FIGS. [-12 only in the configuration of the end walls of the housing and the provisionof a sealing gasket, reference numeral 101 indicates a complete fixture. ln this embodiment, as shown particularly in FIG. 13, end walls 135 are given the same external configuration'as the sidewalls 31 of the first embodiment, with alower outer edge 133 defined by the arris between the wall and a planar ledge 137 the inner edge of which is in turn defined by a stop rib 138. Theend walls 135 are integral with end reflector walls 136.,The in: turned end lips of the enclosure are made as wide as the intumed'side lips, as distinguished from the shortened end lips of thefirst embodiment.

t The provision of the ledge 137 which forms a continuation of the ledges of the sidewalls, permits the use of an uninterrupted sealing gasket 159 around the entire ledge for intumed lip of the enclosure, as preferred, The gasket 159 can be made of any suitable material such as foamed polyurethane or foam rubber which compacts to a very thin but effective seal. The disadvantage of this embodiment over the first embodiment is that in utilizingstandard length lamps and standard sockets, the fixture is slightly longer than a standard modular size, which, particularlywhen a number of fixtures are joined end to end produces alength which is not an integral multiple of standard modules.

In both embodiments, however, the ends of thefixture are illuminated, as-well as the sides, as illustrated particularly in FIGS. 11 and 15 The latter figure, if the lamp is envisioned as turned 90 (as in'FlG. 11) illustrates the end illumination of the second embodiment as well as the side illumination. While the lips are preferably provided with prisms, which substantially enhance the illumination. of the housing walls, as the FIGS. illustrate, some side illumination is provided even without the prisms (note the ray shown in dashed lines in H0.

Numerous variations in the construction of the lighting fixture of this invention, within the scope of I the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure. The fins 7' may be made integral with side or end bounding walls. The wireway80 may be made of any desired configuration. The fixture can be made to accommodate four or more lamps. The prism pattern of the enclosure may be varied, as long as light is directed in the same general way as is illustrated in H6. 11 to illuminate both the bounding walls and the adjacent ceiling areas. The various angles of the hook part finger and cam surface, can vary with the types of materials used for the construction of the hook part and enclosure lens, the configuration of the inboard vertical surface of the lens, which could be rounded or otherwise shaped to facilitate mounting and demounting, and the overall dimensions of the fixture. The hook part can be made of any other suitable plastic materials, such as polyethylene, polypropylene, polytetrafluorethylene, and the like. The configuration of the fixture itself can be varied, from rectangular to square, to polygonal to round. Even in a round fixture, the provision of fins projecting diametrically at four quadrants will produce the illusion of verticality of the bounding walls. In the round or many-sided polygonal versions, two latch members may suffice, mounted diametrically oppositely. The latches themselves may be replaced by other latching means, although the latches illustrated and described have a number of advantages, not'only in being unobtrusive, but in pennitting a lclaim:

l. A lighting fixture comprising a frame with a downwardly directed exteriorly exposed bounding wall adapted to be mounted adjacent a ceiling, an enclosure having a part adjacent a lower edge of said bounding wall and projecting laterally outboardly beyond the outer margin of the lower edge of said bounding wall throughout its periphery, and a plurality of spaced, thin fins projecting; outboard from said bounding wall, the outer edge of each fin defining a line extending from an outer edge of said outboardly projecting enclosure part to a top edge of said bounding wall.

2. The lighting fixture of claim [wherein the bounding wall defines a rectangular frame and a fin projects from each comer at an angle to the meeting walls.

3. The lighting fixture of claim 2 where the fins angle of 135 from the meeting walls. b 4. The lighting fixture of claim 1 wherein the bounding walls are downwardly convergently directed and the fins are sub stantially triangular in side elevation.

5. The lighting fixture of claim 4 whenein the bounding walls define a rectangle, at least one end wall of which is adapted to receive a bushing, am the enclosure is light-transmitting make an throughout its extent and has an intumed lip around its entire are mounted substantially parallel to a planar enclosure bottom wall, said planar bottom wall has a multiplicity of prisms on its emergent face, and said enclosure, has side and end walls, the inturned lip projecting inwardly from said side and end walls, and prisms on its side and end. walls and its intumed lip, said prisms being so related as to direct a substantial amount of light toward and through said intumed lip, hence to the outer surface of the contiguous bounding wall through out the periphery of the fixture. b

8. In a lighting fixture having a fixed frame, a closure with an intumed lip on at least two sidesand a latch for mounting said closure, the improvement comprising a shoulder on an undersurface of said fixed frame and a latch mounted on said frame said latch comprising a spring part, an upwardly opening, inboardly and outboardly movable hook part connected to said spring part and biased outboardly by said spring part,

and a latch shoulder part spaced from the frame shoulder a distance to admit an inturned lip of the closure, the hook part being below the latch shoulder part and opening outboardly and upwardly and being adapted to receive the said intumed lip.

9. A lighting fixture comprising a frame with a downwardly directed exteriorly exposed bounding wall adapted to be mounted adjacent a ceiling, said frame having a shoulder at the lower edge of the bounding wall, an enclosure, light-transmitting throughout its extent, said enclosure having an inturned lip around its entire periphery, an upper surface of said lip being adjacent a lower edge of said bounding wall and projecting laterally outboard beyond the outer margin of the two-stage operation of demounting, which is a safety feature lower edge of said bounding wall, a plurality of spaced, thin fins projecting outboard from the bounding wall between the upper surface of the lip of the enclosure and a top edge of the bounding wall, and a latch mounted on the frame, said latch having a spring part, an upwardly opening inboardly and outboardly movable hook part connected to said spring part and extending below the shoulder of the frame, and a latch shoulder partspacedfmm the frame shoulder'a, distance to admit the said inturned enclosure lip, the hook part being below the latch shoulder part and opening outboardly and being adapted to receive said intumed enclosure lip.

10. The improvement of claim 9 wherein the shoulder is along a lower edge of a downwardly convergently directed bounding wall defining a rectangular frame, the closure is rectangular and extends laterally beyond the outboard edges of the frame at the shoulder, the inturned lip of the closure extends entirely around the rectangular closure and defines an opening smaller than the rectangle defined by the outboard edge of the shoulder whereby a part of the upper surface of the lip can engage the said shoulder.

11. The improvement of claim 9 wherein said latches are provided on opposite parallel sides of said frame and stop means are provided on said frame to limit the outboard movement of said latches.

12. A lighting fixture comprising a frame with a downwardly directed, downwardly convergent, exteriorly exposed bounding wall defining side and end walls, means for mounting an elongated lamp in said frame, an enclosure, said enclosure having a light transmitting planar bottom wall with a mulbeing substantially parallel to the broad surface of the bottom wall and said prisms on the bottom, side and end walls and the lip being so related as to direct a substantial ampunttof light through the inturned lip and against the bounding wall throughout the perimeter-of the enclosure, and a plurality of spaced, thin fins projecting outboardly from the bounding wall of the frame and positioned to extend edgewise between the inturned lip of the enclosure and a top edge of said bounding wall.

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