Improvements in optical systems for devices for light-signal transmission to trains

摘要

395,686. Actuating signals on trains. ZEISS, C., [Firm of], Carl-Zeiss-Strasse, Jena, Germany. Oct. 17, 1931, No. 28883. Convention date, Oct. 25, 1930. Void [Published under Sect. 91 of the Acts]. [Class 105.] In a train control system utilizing a light beam incident on a tetrahedron prism, the two separate reflected pencils, which act on light sensitive cells, are collected by two separate condenser arrangements and brought to separate focus points located at some distance apart. The incident beam is derived from a lamp c an image of the filament of which is formed at b1 by the lens a and prism d. A converging lens e is located at this piont whereby the two reflected pencils A, B from the tetrahedron prism (not shown) form images b111. b112. A lens f images the aperture of lens e on the two condenser systems which each comprise a prism h and a semi-circular glass body gl silvered at the thickened lines. The lens f forms an image of each of the images b111, b112, and the images so formed are located in the planes D2, D1. The glass bodies g1 normally focus these images on selenium cells i1, i2 but a shutter in the plane D1 and controlled by the train speed may cut off the light from one of the cells.