US 1607413 A
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NOV. .16 v 1926' v LIGHTING UNIT Filed Jan' 2, .1925
UNITED s-T ATI-:s lrr'rzlar-oFFlcl-LA lD. TILLSON, 0F EYANSTON, ILLINOIS.
Applicatin'led January2, 1925. Serial No. 81.
` My invention' relates to .lighting units,
particularly for use in connection with electric lamps. Itis well known tothose familiar with the principles of indoor illumination that a semi-indirect fixture possesses great practical advantages. As the bowls employed are translucentthey Y revent the filament from being directly visible, and the transmitted' rays are dispersed in such manner as to avoldthe' productionv of sharply defined shadows A large portion of the light emanating from the lamp is however reflected upward from the bowl to the ceiling, and these rays, together with the raysv Work isA more or less hazardous for an inexperienced person in a household and when the units'are employed in oice buildings and the like the work adds considerably to the cost of general maintenance. Furthermore the p ossibilityof breakage is always to be considered. The general object of my invention isto produce a semi-direct lighting unit which will have a high degree of efiiciency and will at the same time prevent -the`admission of dust. One of the contributory objects of the invention is to provide a unit having a flattened translucent lower portion. As a result of this Va substantial portion of the lightv is reflected upward toward the ceiling instead of being too widely distributed laterally. -Another object is to obtain a unifprm lflux up through the top of the fixture to thereby prevent uneven illumination of the ceiling. further object is to provide a unit through which lamps of the larger sizes may. readily pass and which will at the same time reduce to a minimum the shadows resulting from the presence of the means by' which the individual elements of the units are held to'- rlgether. Another .object is to provide a construction in". whichl the suspending elements by which the canopy supports the transparent and translucent elements may be concealed, thus improving the appearance of' the fixture. Another object is to provide means for masking the inequalities in the inensity ofthe light at dierent parts of the xture.
I accomplish my objects by the mecha.
nism illustrated in the accompanyingdrawings in whichi Figure l is a side elevation of the complete unit showing its external appearance.
Figure 2 is a side elevation of the unit chiefly in central section.
Figure 3 is a bottomfplan section on the line 3 3 Figure 1. y
Like numerals denote like parts throughout the several views.
In theform selected to illustrate the in'- vention the hollow body 1 is of gla, formed being a flattened body 'of revolution sym'- metrical about its central vertical axis and having its median zone about mid height. Thebody has a central opening 2 at the top which in the illustrated form is of a diameter less .than half the maximum diameter of the unit. At the rim of this central openving is a flange 3 which is externally channeled to receive the inner end of set screws 4 by which the said ported.
Below the'median zone the glass is translucent, that is, capable of transmitting a portion of the light rays and also of reiecting a portion of them. This condition may be obtained in different ways, forexalnple, by providing a heavy coat of fired-on enamel. The portion -above the median zone is approximately transparent, but by preference is not entirely so lhaving a light coat of fired-on enamel in order that the light rays or lumins passing through may be somewhat dispersed ,to prevent the formaftion of a direct image of the filament on the ceiling or other reflecting surface above.
Inthe preferred form there is a portlon 6 at the bottom of the body which is shal- ,in a single piece, and is of lenticular shape,
gl-ass body is sup- D lowly 4(lished for the purpose of reflecting the rays almost vertically upward.v The diameter of this portion is here shown to be approximately three-.quarters of the maximum diameter of the fixture.y The portion above the median zone is curved-in the illustrated form being flatly arched, sothat the light rays will pass through without excessive lateral distribution.
As the body is shallow the lamp 8 approaches rather closely to the bottom, which tends to produce a spot of increased brilliance at the central bottom port-ion. To mask this it is desirable to form a Sunburstv 10 at the lower central area.
The lampsocket 14 is enclosed within 'a cap 16 which is preferably truste-conical in genera-l appearance. At the lower rim of the cap is -a reducing ring 18 which is of glass which is approximately transparent like `the upper portion of the main body. This forms part of the closure at the upper part of the body and permits the rays from the filament to pass up through it. A connector ring 2() has an internal flange 22 which rests upon the reducing ring. It also has a depending flange 24 which circumferentially sunrrounds but is spaced slightly from the flange 3 of the body 1. This connector rings among other things forms a housing or dust guard which tends to shed the dust and at the" same time affords a passage for air as the latter expands and contracts due to the heating and cooling of the lamp when the latter is turned on and off.
While the glass parts may he supported -in `different ways from cap` 16 l have shown an advantageous one in which there are three straps 26, which pass up to the inside of the cap and are there fastened by set crews 28. lihese strap-s pass down along the inside of the reducing ring 18 and are secured to the inside of the connector ring 24 by the set screws 4 previously mentioned. These screw into the lower end of the straps and project into the channeled rim 3 of the body 1 and thus hold the parts assembled.
As a result of my invention have produced a lighting unit which has the advan- 1 tages of the ordinary semi-indirect open f bowl unit with lthe added advantage of being closed at the top so as to exclude dust. rll`he elements which form the closure at the top of the unit are a simple form and at the same time permit the air flow resulting from the alternate heating and cooling of' the lamp.
' The unit is of attractive appearance andv may be used in connection ,with any standard form of socket and lamp.
Having thus described my invention what l claim as new `and desire to secure by Letters Patent is:
1. An inclosed lighting fixture having a hollow glass globe with a central opening at the top,a cap of less maximum diameter than said opening and located above the globe, a plurality of straps having their up.- per ends secured to the cap and extending downwardly and outwardly with their lower ends disposed in overlying relationrin respeot to the outer face of the upper end of the globe, a fastening element carried by the lower end of each strap and engaging in a groove in the globe, and a transparent closure between ,the cap and globe supported. on said straps, and having an upwardly extending flange disposed between the straps and cap.y
2. An inclosed lighting fixture having a hollow glass globe with a central openingat the top, a cap of less maximum diameter than said opening and located above the globe, a plurality of straps having their upper ends secured to the cap and extending outwardly and downwardly with their lower ends disposed in overlying relation to the outer face of the'upper end of the globe, a fastening element carried by the lower end of each strap engaging in a groove in the globe, a transparent closure between the cap and globe supported on said straps, a dust excluding ring surrounding the upper end of the globe and through which said fastening elements extend, and a flange on the upper end of said ring rengaging upon the upper surface of said closure.
3. An inclosed lighting fixture having a hollow glass globe with a central opening at the top, a cap of less maximum diameter than said opening and` located above the globe, a plurality of straps having their upper ends secured to the'cap and extending downwardly and outwardly with their lower ends disposed in overlying relation in respect to the outer face of the upper end of the globe, a fastening element carried by the lower end of each strap and engaging in a groove in the globe, a transparent closure between the cap and globe supported on said straps and having an upwardly extending flange disposed between the straps and cap,'
a dust excluding ring surrounding the upper end of the globe and through which said fastening elements extend, and a Hange on the upper end of said ring engaging upon the upper surface of said closure. v
lin witnesswhereof, l' have hereunto subscribed myv name.
EDVIN D. TILLSON.