US579350A

US579350A - James g

Info

Publication number: US579350A
Authority: US
Publication date: 1897-03-23
Anticipated expiration: 1914-03-23

Description

(No Model.)

J. G. PENNYGUIOK.

SHADE OR GLOBE.

No. 579,350. Patented Mar. 23. 1897.

llnrrnn STATE Farnivr Orrrcn.

JAMES G. PENNYOUIOK, OF TORONTO, CANADA, ASSIGNOR TO THE PRIS- MATIO GLASS COMPANY OF TORONTO, LIMITED, OF SAME PLACE.

SHADE 0R GLOBE.

SPECIFICATION forming part of Letters Patent No. 579,350, dated March 23, 1897.

' Application filed May 4, 1896. Serial No. 590,131. (No model.)

To aZZ whom it may concern.

Be it known that 1, JAMES G. PENNYC'UIGK, a subject of the Queen of Great Britain, residing at Toronto, in the county of York and Province of Ontario, Canada, have invented a certain new and useful Improvement in Shades or Globes, of which the following is a specification, reference being had to the accompanying drawings.

This invention is designed to provide a shade or globe particularly adapted for arelights, but applicable also to other purposes where the diffusion of light is desired.

It is well known that the intense light given out by the electric arc requires to be softened to avoid injury to sight. This is generally done by the aid of frosted or ground glass globes. These, however, obscure the light to such a degree that probably not half of the light given off by the arc is utilized when a ground-glass globe is used. To overcome this objection is the object of this invention, which is accomplished by the construction hereinafter more particularly described and then definitely pointed out in the claims.

In the accompanying drawings, Figure 1 is a side elevation of a shade constructed according to my invention with part broken away. Fig. 2 is a cross-section of the same. Fig. 3 is a cross-section of a similar shade having its body in two parts. Fig. 4 is an enlarged sectional detail. Figs. 5, 6, 7, and 8 are outline views, on asmaller scale, of different forms of shades or globes on which the principle of my invention may be carried out, the prismatic ribs of the curved sides of said figures being shown in the enlarged sectional detail above described as Fig. 4.

Referring now to the details of the drawings by figures, 1 represents the body of the shade, which is preferably octagonal in crosssection, as clearly shown in Fig. 2, and having vertical sides 2 and inclined bottom 3. On each side or panel are ribs or prisms 4, the lines of which are made of such a shape that the rays of light from the are striking the inside of the upper ribs will be totally reflected in a downward direction, as indicated in Fig. 1, while light striking the lower prismatic ribs will be refracted and bent from its downward course slightly toward the horizontal.

I show a reflector or cover 5 at the top, but this may be left off or changed in form Without departing from the spirit of niyinvention. One standing rule should, however, be observed in shaping the mold for making the prismatic ribs, and that is that the angles or upper edges of the prismatic ribs should vary only through a downward angle of ninety degrees from a perpendicular to the vertical axis of the shade and that the angles of the lower edges of the prismatic ribs vary only through an upward angle of ninety degrees from the same perpendicular. If this rule is not observed, it is rather difficult tomold a shade with prismatic ribs, as some of their faces would form dovetails, which would prevent the parts of the mold of the ordinary construction being withdrawn sidewise from the finished article. As shown in the drawings, the upper face of each prism or prismatic rib makes substantiallyan angle of one hundred and five degrees to the surface of the side of the shade, while the lower face similarly makes an angle of forty-five degrees.

Although I show and describe a shade as being molded of a polygonal shape, yet a measure of utility may be obtained with a shade round in cross-section. The diffusive power of the prismatic ribs is much increased, however, by the use of the polygonal form, as there is a tendency to focus and so concentrate the light when the shade is made globularor circular in cross-section, which is avoided when the shade is made of polygonal form. This I have proved by experience, as I found that with the ribs running around the globe or shade in curved lines the light from the lamp appears to be focused to a considerable extent in a vertical line directly between the light and the spectator, but with the shade having a polygonal shape, as the ribs are fiat orsubstantially so, this focusing is avoided and the light is diffused over the entire surface of the globe or shade.

I have described so far only one style of shade, but do not limit myself to this form, as many different kinds of shades may be made without departing from the spirit of myinvention, and, as examples, I would refer to Figs. 5, 6, 7, and 8, which show on a smaller scale outline views of different forms of shades or globes in which the principal feature of my invention may be carried out with more or less success, but in view of the different shapes of these globes or shades it would. be difiicult to carry out all over the same the peculiar arrangement of the prisms that I believe to be essential to the most useful result, except in that form shown in Fig. 8. These forms, however, are only given as examples of different styles that might be employed without limiting myself to these only. It will of course be understood that Figs. 5, 6, 7, and 8 are shown only in outline and that the shades or globes are in reality formed with prisms thereon, as shown in the enlarged detail, Fig. at.

I prefer to make the shades integral, but in some cases I may make them in sections, as indicated in Fig. 3, where a shade is shown formed in two parts with flanges 6 on each, by which they may be joined with any suitable cement or other fastening means.

For many years various means have been tried for diffusing and tempering the intense glare of the electric are, such as frosted and colored glasses, but as these absorb so much light they are wasteful and useless where extensive illumination is required; but when my improved shade is used the rays proceeding from the are are collected and diffused in a horizontal and downward direction, so as to not only give the lamp much more illuminating power, but also to so diffuse it that it may be looked at without injury to the eye.

I am aware of the English Patent No. .111 of 1859 and United States Patent No. 538,193 and also of the foreign patents granted on the shade shown in the latter and make no claim to anything shown therein, as I regard my invention as essentially different therefrom.

In the following claims I have stated the precise angles of which I prefer to make the prismatic ribs, but it will be easily seen that a slight variation from said angles will not be a departure from my invention, and I therefore intend my claims to cover my in- Vention if such slight variations are made.

NVhat I claim as new is 1. A shade or globe for electric or other lamps, having a series of horizontal prismatic ribs molded thereon, the said ribs having their upper faces formed at an angle of one hundred and five degrees to the surface of the side of the shade, and the lower faces of said prismatic ribs formed at an angle of fortyfive degrees, substantially as and for the purpose specified.

2. A shade or globe for electric or other lamps, made of polygonal form and having a series of horizontal prismatic ribs molded thereon, the said ribs having their upper faces formed at an angle of one hundred and five degrees to the surface of the side of the shade, and the lower faces of said prismatic ribs formed at an angle of forty-five degrees, substantially as and for the purpose specified.

A shade or globe for electric and other lamps, of curved outline in vertical section and of polygonal form and having a series of horizontal prismatic ribs molded thereon, the said ribs having their upper faces formed at an angle of one hundred and five degrees to the surface of the side of the shade, and the lower faces of said prismatic ribs formed at an angle of forty-five degrees, substantially as and for the purpose specified.

4. A shade or globe for electric or other lamps molded in sections, the said sections havinghorizontal prismatic ribs formed thereon, the said ribs having their upper faces formed at an angle of one hundred and five degrees to the surface of the side of the shade, and the lower faces of said prismatic ribs formed at an angle of forty-live degrees, substantially as and for the purpose specified.

In testimony whereof I affix my signature, in the presence of two witnesses, this 22d day of April, 1896.

JAMES G. PENNYCUICK. IVitnesses:

Tnos. E. ROBERTSON, IV. E. CLENDANIEL.