US 2741694 A
Description (OCR text may contain errors)
April 10, 1956 v THOMSTAD EI'AL DE ASSEMBLY FOR LIGHT SOURCES Filed March 17, 1953 2,741,694 SHADE ASSEMBLY FDR Ll'Gl-l'l SGURQES 11B SHAPE luague Vilhelm Thomstad, Moss, aud Arnold Wiig,
Harreby Edd, near Holden, Norway Application March 17, 1953, 521' Claims priority, apolieatioh Norway 2 Claims. (Cl. Zed-51.11}
The present invention relates to a shade assembly for light sources of tubular shape, which shade l is of the kind which is detachably fixed proper by means of grips or .he 1 embrace the glass tube.
Shades of this kind have been which the grips are made in one proper and the whole unit is produced from some suitable transparent or dittusing material, suc as thermoplastic resin. The grips, which form pairs of toothor rib-like protrusions, are d ected against and arranged on either side of the glass tune of the lamp so as to grip same.
Owing to the relatively large tolerances which are allowed with respect t the diameter of the lamp tube, as the case is for i stance in the manufacture of the fluorescent lan s, cases it is, not possible to get the shade safely filed to the tubes of the smallest diameter, and the object or" the invention is to avoid he shade is held fast to the LE5 sh this disadvantage that tlamp tube by means or" a s iugy clamp which embraces at least 200 of the tube and which is preferably detachably connected to the shade proper.
An embodiment of the invention is to be described below with reference to the drawing, in which:
Fig. 1 shows, in perspective, a tubularly shaped light source, for instance a fluorescent l" having a number of shades according to the iuven. on fixed to it, which shades serve the purpose of either refl cting, diminishing or intercepting the lur" hold fast said clam s on the tube.
The other or lower ends 8 of the mp 3 are provided with teeth or ribs which are directed inwardly against one anotr erage correspondingly shaped slots 11 formed'on either s1 e of a rib sha ed portion ll; which is formed in one ce with the shade 2. Said rib portion ill may be solid or, in the present case, provided with apertures formed between trausverse ribs so as to let through the main part of the luminous flux within this region of said rib iii.
The main part of the shade is formed by two oppo- 6 ite blades each of which form about a quarter of 5 a hollow cylinder, both connected with the rib 10 by intermediate portions 13 integral with the blades 14 and said rib ll) as well, which portions 13 may be either solid or provided with apertures formed between ribs 13', similar to the apertures 12.
The inner or concave surfaces of the blades 3.4, fac- 2,741,694 Patented Apr. 10, 1956 ing toward the lamp 1, are smooth in order to facilitate cleaning of same, whereas the outer or convex surfaces are provided with impressions of some kind, in the present case forming parallel ribs of substantially prismatic shape, which will serve to refract the light rays and redistribute same more or less, as may be desired.
in the embodiment shown in the drawing the connection between the clamp 3 and the shade 2 is formed by a kind of dovetail connection, but obviously any other connection may be used which will serve the same purpose, namely increase the pressure of the lower clamp ends against the rib it when the clamp is forced over the lamp tub so that the upper part of the side portions 5 or" said clamp 35 are pressed out against the springy action of the middle portion 4.
The slots iii. may have the same length as the ribs so that the clamp or clamps 3 may be fixed at any place between the ends of the shade, contrary to the embodiment in which the clamps can only be fixed in the regions of the ends of the shade.
When so-called lighting bands are to be arranged, a number of shades may be fixed to the tubular lamps with abutting ends so that said band will also cover the ends of the lamps and their mountings.
As appears from the drawing the upper ends of the side portions 5 of the clamp 3 embrace together at least 280 of the lamp tube 1 when seen in cross section, so that in all events even the tubes having the smallest diameter within the tolerances may be used in connection with the shade according to the invention.
The clamp may be made from any suitable material, such as metal, but preferably it is formed of a transparent, springy, thermoplastic material so that same will not throw any shadow on the shade. Similarly, the shade may also be made of a transparent or diffusing material, such as some thermo lastic resins. The shade as well as the clamp may be either clear or opalescent, and either white or coloured.
The mounting of the shade on the lamp tube is made by first applying the clamp to the shade as shown, and then forcing the clamp over the lamp tube. Thereby a good connection is obtained between the lamp and the clamp as well as between said clamp and the shade.
in the claims:
1. A shade assembly for light sources of tubular configuration; said assembly comprising a shade, at least one E-l-shaped clamp having two spaced arms connected, intermediate their ends, by a cross-piece, at least said cross-piece of the clamp being resilient, said arms at one end being formed to substantially embrace the tubular light source, and iuterengaging means on the other ends of said arms and on said shade for detachably connecting said clamp to said shade, said means on the shade including a centrally located longitudinal rib thereon projecting from the shade in the direction toward the tubular light source and gripped between said other ends of the clamp arms.
2. A shade assembly according to claim 1, wherein said interengaging means includes said longitudinal rib and has oppositely opening slots extending longitudinally in the sides thereof, and projections on said other ends of the clamp arms directed toward each other to engage removably in said slots.
leelferences Cited in the file of this patent UNITED STATES PATENTS