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6,991 · Nelke · "Improvement in Incidence Windows or Vault Lights" · Page 2 Home  > Prism Glass  > Patent Index  > Page 2

6,991: 2 of 3

2 A.D. 1886.--Nº 6991. Complete Specification Nelke's Improvement in Incidence Windows or Vault Lights.     Figure 5 is a sectional view of the slanting frame and a lens like that shown in Figure 4.     The lenses A are of prismatic form and are held in place on a slanting frame B by the shoulders or offsets, c, and c¹, on their sides. The offset c is situated at one side near the top and plane of incidence d, and the other offset c¹, is at the opposite side and lower down at the plane of reflection e. The frame B has holes which are filled by the lenses like a plug, the offsets hold the lens in position on the frame B, and maintain the plane of incidence d, level; the light from above striking the plane of incidence penetrates to the plane of reflection e and thereby is thrown in a horizontal direction indicated by the dart in Figures 3 and 5. While the desired light is thus obtained, the slanting position of the frame acts as a water shed.     The frame may be provided with ventilating slots f between the rows of lenses, and hinged covers g employed to close said slots. This ventilating feature may however be dispensed with and the advantage of the glasses for reflecting light may be employed in the windows opening on spaces or alley ways between buildings.     Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is:--     1st A lens of prismatic or approximate prismatic form having shoulders or offsets c, c¹, one at one side near the top of the plate of incidence, and the other at the opposite side and below the first one at the plane or reflection, as set forth.     2nd The combination of a lens having shoulders or offsets c, c¹, one at one side near the top at the plane of incidence, and the other at the opposite side and below the first one at the plane of reflection and a frame having holes each of which is filled by a lens inserted in it like a plug, as set forth.     3rd An incidence window comprising the frame B provided with the described lenses placed in rows and having slots f between said rows provided with suitable covers, as set forth.         Dated this 22nd day of April 1886. LOUIS NELKE. LONDON: Printed by EYRE and SPOTTISWOODE, Printers to the Queen's most Excellent Majesty. For Her Majesty's Stationery Office. 1886.