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D23,804 · Evans · "Design for a Prism-Reflector for Area-Gratings" · Page 1 Home  > Prism Glass  > Patent Index  > Page 1

D23,804: 1 of 2

Patents: 283 of 530	UNITED STATES PATENT OFFICE GEORGE EVANS, OF DETROIT, MICHIGAN.
DESIGN FOR A PRISM-REFLECTOR FOR AREA-GRATINGS. SPECIFICATION forming part of Design No. 23,804, dated November 13, 1894. Application filed July 20, 1894. Serial No. 518,491. Term of patent 7 years.

To all whom it may concern:     Be it known that I, GEORGE EVANS, a citizen of the United States, residing at Detroit, county of Wayne, State of Michigan, have invented a certain new and useful Design for Prism-Reflectors for Area-Gratings; and I declare the following to be a full, clear, and exact description of the design, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.     The characteristic features of my design consist in the rectangular top surface of the prism, the converging rectangular lower side surfaces, and the vertical triangular shaped end surfaces.     Figure 1, is a perspective view of my newly designed prism, and in this view the rear or concealed edges are indicated by dotted lines. Fig. 2, is a longitudinal section. Fig. 3, is a cross section.     A, indicates the prism which is rectangular on its top face and from the top-face downward has four vertical and rectangular sides. Beneath these vertical sides there extends inward a horizontal flange furnishing the point

of engagement between the prism and the supporting frame. From the flange downward two of the sides of the prism converge to an edge, and two of the sides drop vertically downward, thus giving to the entire prism the appearance of a triangular prism joined at one of its sides to a rectangular prism; the rectangular prism being larger than the triangular prism to which it is joined.     In the drawings B, indicates the rectangular upper surface of the prism; C and D, and B and F, the four vertical sides of the rectangular prism; e, d, c, f, the four flanges; G, H, the two converging sides of the triangular prism, and J, K, the two vertical sides or ends of the triangular part of the prism.     Having thus described my invention, what I claim is--     The design for a prism reflector for area gratings shown and described.     In testimony whereof I sign this specification in the presence of two witnesses. GEORGE EVANS. Witnesses:     D. W. BRADFORD,     C. F. BURTON.