US655220A - Glass prism-plate. - Google Patents

Description

Patnted Aug..7, I900. a. FUGMAN.

GLASS PRISM PLATE.

(Application filed May 31 1900.

(No Model.)

lNVENTOR NITED STATES PATENT. OFFICE.

GODFREY FUGMAN, OF CLEVELAND, OHIO.

GLASS PRISM-PLATE.

SPECIFICATION forming part of Letters Patent No. 655,220, dated August 7', 1900. Application filed May 8, I900. serial No. 15,313. (No model.)

T0 at whom it may concern:

Be it known that I, GODFREY FUGMAN, a resident of Cleveland, in the county of Guyahoga and State of Ohio, have invented certain new and usefullmprovements in Glass Prism- Plates; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same.

My invention relates to improvements in glass prism-plates.

The object of this invention is more especially to improve upon the construction of prism-plate disclosed in United States Letters Patent No. 627,848, granted to me June 27, 1899, and to produce a prism-plate that has a vast refracting capacity and great brilliancy, that is exceedingly strong, and requires less material in its construction.

With this object in view the invention consists in certain peculiarities of construction hereinafter described, and. pointed out in the claims.

In the accompanying drawings, Figure I is an inner side view of my improved prismplate. Fig. II is a view in perspective of a portion of the plate. Fig. III is a section on any one of lines III III, Fig. I.

My improved prism-plate comprises a glass plate whose body portion is preferably plain and smooth on its outer and light-receiving side a and has its inner and light-refracting side provided with numerous inwardly and laterally projecting prismatic lugs 19. Some of the lugs that are located next adjacent the edges of the plate are not perfect or complete lugs; but each complete lug b has preferably a diamond-shaped or lozenge-shaped refracting-surface c, facing inwardly and arranged obliquely to the plane of the body portion of the plate. Preferably each complete lug b has its refractin'g-surface 0 arranged with two opposite corners thereof in line horizontally and with the two remaining corners forming the upper extremity and lower extremity, respectively, of the said surface, and the lug is widest at its central portion centrally between its upper and lower extremities. Each complete lug b of the plate illustrated is thinnest at its lower angular extremity and is gradually increased in thickness from the said extremity toward its upper extremity, and the top edges of the lug form two refracting shoulders or surfaces 0 and c, that diverge from the upper extremity of the lug toward the lugs central portion and slope also in the direction of the diamond-shaped or main refracting-surface c of the lug, and hence the said lug in the case illustrated has three refracting-surfaces--a main refracting-surface c,facin'g inwardly and somewhat downwardly, and two other and narrower refracting-surfaces 6 and e, that form the top edges of the lug and diverge downwardly from the upper extremity of the lug and slope somewhat toward the lugs main retracting-surface. Preferabl y the lugs 17 are arranged in horizontal rows, with the lugs of each row of lugs alternating with the lugs of the adjacent row or rows of lugs, with each side corner of each lug of each row of lugs coincident orapproximately coincident with the adjacent side corner of the adjacent lug of the said row of lugs, with the upper corner of each lug of each row of lugs coincident or approximately coincident with adjacent side corners of two adjacent lugs of the next upper row of lugs, and with the lower corner of each lug coincident or approximately coincident with the adjacent side corners of two adjacent lugs of the next lower row of lugs. It will be observed also that the adjacent refractiug edges 6 of adjacent lugs of each row of lugs converge downwardly and meet at the inner extremity of the junction of the upwardly-converging sloping edges 6 of a lug of the next lower row of lugs, so that a V-shaped recess is formed between adjacent downwardly-converging sloping edges e of adjacent lugs of each row of lugs and that the main refracting-surface c of a lug of the next upper or adjacent row of lugs overhangs the said recess.

By the construction of prism-plate hereinbefore described the objectionable casting of shadows by the lugs is avoided,a large refract ing capacity is obtained, the plate possesses great brilliancy, is exceedingly strong and durable, and can be manufactured with facility and with comparatively-little material.

What I claim is l. Aprism-plate of the character indicated, having its inner side provided with a plurality of prismatic lugs that have each a main ICO sloping refracting-surface that faces inwardly and is arranged obliquely to the plane of the body portion of the plate, which surface is widest at its central portion and gradually reduced in width toward its upper and lower extremities.

2. A prism-plate of the eharacterindicated, having its inner side provided with a plurality of lugs that have each a main sloping surface that faces inwardly and is arranged obliquely to the plane of the body portion of the plate, which surface is widest at its central portion and reduced in width toward its thicker and thinner extremities, and two shoulders or edges formed upon opposite sides, respectively, of the thicker portion of the lug.

3. A prism-plate of the character indicated having its inner side provided with a plurality of prismatic lugs that have each a main sloping surface that faces inwardly and is arranged obliquely to the plane of the body portion of the plate, which surface is widest at its central portion and gradually reduced in width toward its upper and lower extremities, and two shoulders or edges formed upon opposite sides, respectively, of the thicker portion of the lug and extending and diverging from the thicker extremity of the lug toward the central portion of the lug.

4. A prism-plate of the character indicated, having its inner side provided with a plurality of prismatic lugs having each a diamond-shaped or lozenge-shaped refractingsurface facing inwardly and arranged obliquely to the plane of the bodyportion of the plate and arranged with two corners thereof forming opposite side extremities, respectively, of the surface and with the remaining two corners thereof forming the upper extremity and lower extremity, respectively, of the said surface.

5. A prism-plate of the character indicated, having its inner side provided with rows of prismatic lugs that are each provided with inwardly-facingrefraeting-surfaces arranged obliquely to the plane of the body portion of the plate and widest at the central portion.

6. Aprism-plate of the character indicated, having its inner side provided with rows of prismatic lugs having lozenge-shaped or diamond-shaped refracting-surfaces c facing inwardly and arranged obliquely to the plane of the body portion of the plate.

Signed by me at Cleveland, Ohio, this 28th day of April, 1900;

GODFREY FUGMAN.

Witnesses:

G. H. DORER, A. H. PARRATT.

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