US2643328A - Electric light fixture shade and chassis construction - Google Patents

Description

June 23, 1953 A. R. ELMENDORF 2,643,328 ELECTRIC LIGHT FIXTURE SHADE AND CHASSIS CONSTRUCTION Filed May 18, 1950 2 Sheets-Sheet 1 INVENTOR flrfizur ..Elmend0rf 43% 42 63% r 65% v k I, ATTORNEYS June 23, 1953 A. R. ELMENDORF 2,643,323

ELECTRIC LIGHT FIXTURE SHADE AND CHASSIS CONSTRUCTION 2 Sheets-Sheet 2 Filed May 18, 1950 INVENTOR fli'fizzzr R, Elmen dorf' BY U/I Patented June 23, 195?;

ELECTRIC LIGHT FIXTURE SHADE AND CHASSIS CONSTRUCTION 'Arthur R. Elmendorf, Woodbridge, Conn., as-

signor to-The Safety Car Heating and Lighting Company, Inc., New Haven, Conn., a corporation of Delaware Application May 18, 1950,Serial No. 162,704

. 4 Claims. 1 My invention relates to an electric lighting fixture, and more particularly to shade and chassis constructions for such a fixture.

Elongated light sources are finding many new applications, particularly with the advent of the fluorescent tube, and modern fixtures to accommodate the tubes generally may comprise a specially shaped chassis or plate which is secured to a bulkhead and to which is attached the lighting tube together with a translucent shade encircling the tube and affixed to the plate to diffuse the light and protect the tube from injury. Fixtures adapted for running longitudinally overhead, as across a ceiling, sometimes are equipped with a convex shade consisting of a series of abutting elongated sectionswhich have flanged edges that rest on the ceiling chassis or plate, and accordingly they permit convenient access to the fluorescent tube. This construction, though simple,is not satisfactory in many instances, for when the fixture is used on a moving vehicle excessive freedom in the fitting of the shade "causes rattling, and should the shade become warped or otherwise deformed, it may not remain in place and consecutive sections willbe out of alignment. Also, a fixture with a shade which merely slides orsnaps into place is easily tampered with. v

Accordingly, it is among the objects of this invention to provide a fluorescent'fixture with a flexible shade having flanges which interlock with the ceiling plate. Another object is to provide a locking construction for such lighting fixture so that the shade cannot be removed unless the interlocking flanges of the shade are moved up-- wardly and inwardly. It is also an object to pro vide a shade which fits securely to the fixture and which may be locked or held tightly in place. A further object is to provide a spacer between successive longitudinal sections of a shade which limits movement of the shade sections both horizontally and vertically and which keeps the shade sections in alignment. Another object is to provide a shade of the type described which will not be distorted at the ends when a spring spacer is placed between shade sections. A still further object is to provide a shade which issecurely held to the fixture even when spacers are not employed. These and other objects will be apparent from the description which follows.

The invention accordingly consists in the features of construction, combinations'of elements, arrangements of parts, and relation and order of each of the same to one or more of the others, all as will be illustratively described herein and inside.

2 the scope of the application of which will be indicated in the claims.

In the drawings:

Figure 1 is a partial perspective view of an overhead fluorescent lighting fixture;

Figure 2 is an enlarged sectional view taken along line 2-2 of Figure 1;

Figure 3 is a partial sectional view taken along line 3-3 of Figure 2;

Figures 4, 5 and 6 are enlarged fragmentary views of the left flange of the shade as it interlocks with the ceiling plate channel; and

Figure '7 is a sectional view of an alternate securing arrangement for a shade forming another embodiment of this invention.

Similar reference characters refer to similar parts throughout the several views of the drawings.

In the illustrative embodiment of the present invention, a long fluorescent lighting fixture, suitable for overhead use, containing a succession of fluorescent tubes, is provided with a series of flexible plastic shade sections. Each shade section is somewhat elliptical in cross-section, but is open at the top so as to substantially encircle the lighting tube and fit onto a plate, which attaches to the ceiling in any convenient manner. This plate supports the tubes on the usual electrical fittings and has upturned lips forming underhanging longitudinal channels along the The edges of the shade sections on each side of the top opening are flanged and have lugs attached to interlock over the upturned lips of the ceiling plate to hold the shade in position. The plate channel and shade flange are shaped to permit part of the shade section to lie a short distance below and parallel to the underside of the channel so that the shade section must be elevated to a point Where the lugs pass over the upturned lips on the channel before it can be removed. In consequence, a shade section cannot be removed unless its lugs are shifted first upwardly and then horizontally until the entire shade flange clears the channel. The shade section can then be lowered free of the fixture.

The ends of each shade section are square so that consecutive sections may abut one another, and in one embodiment of my invention a spring spacer is placed around the outside at the juncture of two shade sections, and, being T-shaped in cross-section along the bottom, it fits between the sections and covers the joint. The upper ends of the spacer are flat toextend between the shade and the underside of the ceiling plate channel; they are of sufficient thickness to pre 3 vent removal of the shade until the spacer is taken ofi, i. e. the shade cannot be lifted sufficiently for its lugs to clear the upturned lips of the plate channel. The interlocking parts are rather closely fitted, and movement of the shade is limited horizontally as well as vertically so that spring action of the spacer will align the shade sections. Distortion of the shade ends is prevented, however, by the lugs fitting,

firmly against the upturned lips of the channel. The fixture, when assembled, is accordingly trim and secure, and the various. parts are'held together tightly by virtue of their interlocking features.

Another embodiment of the inventionqemploys a similar ceiling plate and identical shade sections, but the fixture is adapted for usewithout spacers. Instead, leaf springs are secured to the ceiling plate which press against the top edges; of the shade to hold the lugs in the channel. Here too, a shade section may not be removed until its lugs are shifted both upwardly and inwardly, but resistance to upward movement is provided by the leaf springs which hold the various parts securely in place.

Referring now to the drawings, in Figure 1 an overhead lighting fixture, generally indicated at I0, is shown with a ceiling plate I2 fixed to ceiling I4. Part of a fluorescent tube I6 may be seen at the left, this being supported below ceiling plate I2 by electrical sockets (not shown) Successive shade sections I8 and I9 are attached to ceiling plate I2 by an arrangement hereafter to be described, and a spacer 20 is fitted between the two shade sections. The shade is made of a suitable flexible, translucent material, such as plastic, and spacer 20 is preferably a similar materialthus providing a non-metallic spacer and joint covering band (however, a resilient metal band may be employed if desired).

As seen in Figure 2, ceiling plate I2 is attached to ceiling I4 by screws 22. Sides 24a. and 241) project downwardly and have contiguous horizontal portions 26a and 26b, respectively, which extend inwardl of the sides. The horizontal portions have upturned lips 23a and 28b forming channels into which shade lugs 38a and 38b fit as described below. 7

Shade I8 has a large convex portion 30 which surrounds light tube I6 at a distance therefrom, and convex sides 32a and 32b with inwardly extending horizontal portions 34a and 342) which lie parallel to similar portions 26a and 26b of plate I2. Shade I8 is open at the top and is provided with inverted L-shaped flanges 36a and; 361) which extend up over lips 28a and 2319, respectively. These flanges in turn have lugs or strips 38a and 33b which overhang the lips.

Spacer 26 is contoured to rest snugly around the periphery of the shade and has an arcuate projection or tongue 40 (Figs. 2 and 3) projecting perpendicularly on its inner side to separate sections I8 and I9, leaving an outside strip. 42 on either side as a flange to cover the exposed ends of the shades. Side 44a of spacer 20 is flat and spring-fits around convex side 32a of shade I8, and a straight section 46a lies snugly over horizontal portion 34a. Spacer 20 is preferably made from a resilient material, and side 44a is prestressed inwardly so that a compression force will be exerted around the periphery of the shade sections at their juncture. The right half of spacer 20 is similarly constructed with side 44b terminating in straight section 46b, and thereby 4 two shade sections are securely held in alignment and the seam is attractively concealed.

The shade sections are made from a translucent material which diffuses the light emitted by tube I6; they are sturdy enough to protect the tube, and they possess sufiicient resilience to permit sides 32a and 32b to be flexed inwardly until flanges 36a and 36b clear lips 28a and 28b ofrplate I2 when the shade is to be attached.

Both sides need not be flexed, however, to place "shade I'8' in the position shown in Figure 2, for

if one edge is inserted into a plate channel at an. angle, the other edge can be slipped into the opposite channel by stressing the adjacent side.

. If: sides a and. 24b of plate I2 are made flexible, then arigid shade section can be used; however, it is preferable to have the shade flexible because of the availability of suitable inexpensive and lightweight plastic materials for this purpose, and because of the greater convenience of manipulating the shade.

When shade I8. is fitted to plate. I2 and spacer 20 is snapped in place around it by expanding sides 44a and 44b, the shade is securely held in proper alignment and cannot be removed. In this normal position. of use, straight section 46a of spacer 20 lies. between horizontal portions 26a and 3411 (Figure 4), and these coacting parts have relative dimensions which prevent lugs 3811 from clearing lip 28a (Figure 5); hence, shade section I8 cannot be removed from ceiling plate I2, until. spacer 20 is first removed (Figure 6). These illustrations. are of. the left side of the fixture, but the same construction is providedfor the opposite side (Figure 2). When. a taut spacer is employed, adjoining shade sections are held firmly in alignment because lugs 38a and 38b bear against lips 28m and 28b, respectively, to arrestv inward distortion. Accordingly, there is provided a lighting. fixture with rigidly held interlocking parts which may be assembled with comparative ease- In. another embodiment. of the invention, shown. in Figure '7', the spacers between shade sections are not employed. Shade I8 is essentially the. same asv shade I8, and it encircles a lighting tube I6" that is suspended. from ceiling,

plate I2 which is attached to ceiling I4 by screws 22. Corresponding horizontal portions 340/ and 34b, flanges 36a and 36b, andlugs 38a. and 38b are provided for the functions previously described for similar parts of shade section I8. Plate I2 is, constructed like plate I2 with sides-24a and 24b, horizontal portions 26a and 26b, and upturned lips 28a and 28b, while lugs 38a. and 38b slip into the channels thus formed in the manner previously described for plate I2. and shade section I8. A plurality of leaf springs 48 are secured to the underside of plate I2 and extend over the top of flanges 36a and 36b to retain shade I8 in place. Springs 48 are strong enough. to hold lugs 38a and 38b firmly seated intheir respective channels, while these. lugs are closely fitted inside lips 28a and 28b, with the result. that shade I8 is confined against either: horizontal or vertical movement. Consequently, with this arrangement, spacers between successive shade sections need not. be used, and one less. operation is necessary to assemble the fixture. Thus, a practical and efficient lighting fixture has been. achieved in which the several. objects hereinabove set forth have been successfully accomplished.

As many possible. embodiments may be made ofthefeatures of the above invention, and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

What I claim is:

1. In a lighting fixture, the combination of a trough-shaped base member adapted to be secured to a ceiling or the like and having depending sides terminating in inwardly extending horizontally-disposed sections bordered by integral, substantially vertically-disposed flanges to form two longitudinal channels at the bottom of and inside said depending sides, a tubular light source suspended longitudinally below said base men1- ber, a plurality of light transmitting shade sections substantially trough-shaped in cross section adapted to be suspended from the channels in said base member, the longitudinal edges oi said sections being substantially U-shaped in cross section to provide two horizontal portions joined by a vertical portion, the upper horizontal portions extending outwardly and being provided with a series of depending lugs spaced from said vertical portions and thinner than the height of said vertical portions to rest upon the bottom of said channels in said base member, and resilient means associated with said fixture and adapted to press said shade sections against said. base member so that said lugs fit snugly in said channels and the assembly is held rigid against vibration.

2. The lighting fixture combination as defined in claim 1 in which the resilient means comprises a series of U-shaped resilient strips with inturned ends adapted to fit about said sections and spaced longitudinally therealong with their free ends extended between the bottom of the channel portions of said base member and the portions of said shade sections immediately therebeneath to hold said lugs firmly against the bottom of said channels.

3. The lighting fixture combination as defined in claim 1 in which there are a series of resilient spacer elements in the form of U-shaped strips with longitudinal ridges therein and inturned ends adapted to fit over the ends of adjacent shade sections with the ridges disposed between the ends of said sections and said elements fitting around said shade sections with the ends thereof disposed beneath said channel portions to hold said lugs firmly against the bottom of said channels.

4. The lighting fixture combination as defined in claim 1 in which the resilient means comprises a plurality of leaf-spring members secured to said trough-shaped member and depending downwardly to engage the upper horizontal edges of said shade sections to urge said lugs against said channels.

ARTHUR R. ELMENDORF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,746,339 Doane Feb. 11, 1930 1,955,935 Shepmoes Apr. 24, 1934 2,090,239 Strang Aug. 17, 1937 2,225,217 Hicok Dec. 17, 1940 2,229,145 Stewart Jan. 21, 1941 2,269,182 Claspy et al Jan. 6, 1942 2,319,732 Guth May 18, 1943 2,440,603 Guth Apr. 17, 1948 2,465,141 Wakefield Mar. 22, 1949

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