GB644052A - Improvements relating to light signals - Google Patents

Improvements relating to light signals

Info

Publication number
GB644052A
GB644052A GB20659/47A GB2065947A GB644052A GB 644052 A GB644052 A GB 644052A GB 20659/47 A GB20659/47 A GB 20659/47A GB 2065947 A GB2065947 A GB 2065947A GB 644052 A GB644052 A GB 644052A
Authority
GB
United Kingdom
Prior art keywords
signal
focus
light
lens unit
coincident
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB20659/47A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Mobility Ltd
Original Assignee
Westinghouse Brake and Signal Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Westinghouse Brake and Signal Co Ltd filed Critical Westinghouse Brake and Signal Co Ltd
Publication of GB644052A publication Critical patent/GB644052A/en
Expired legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/08—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters for producing coloured light, e.g. monochromatic; for reducing intensity of light

Abstract

644,052. Signal lamps. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. July 30, 1947, No. 20659. Convention date, May 18, 1945. [Class 75(iv)] In a light signal emitting a substantially parallel beam and comprising a light unit A and a lens unit C with coincident focus a colour filter adjacent the common focus is of such a shape and is so positioned that any external light rays entering the signal through the lens unit will, if reflected only once by the colour filter, be reflected away from the signal beam. A hollow conical colour filter 20 is positioned near the common focus with its axis along the axis of the signal and the surfaces of the cone are so inclined that external rays entering the signal in a direction substantially parallel to the emitted beam will not strike the cone at right angles so as to be returned along their incident paths. Three such conical filters may be mounted on a rotatable arm 16 so that any one of the filters can be interposed in the light beam. The light unit A comprises an elliptical reflector 12 with one focus coincident with the focus of the lens unit, and the other coincident with the filament of an electric lamp 10. The lens unit C comprises a doublet formed by two plano-convex lenses.
GB20659/47A 1945-05-18 1947-07-30 Improvements relating to light signals Expired GB644052A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US644052XA 1945-05-18 1945-05-18

Publications (1)

Publication Number Publication Date
GB644052A true GB644052A (en) 1950-10-04

Family

ID=22055749

Family Applications (1)

Application Number Title Priority Date Filing Date
GB20659/47A Expired GB644052A (en) 1945-05-18 1947-07-30 Improvements relating to light signals

Country Status (1)

Country Link
GB (1) GB644052A (en)

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