GB639761A - Improvements relating to electric lighting fittings - Google Patents

Abstract

639,761. Electric lighting fittings. BRITISH THOMSON-HOUSTON CO., Ltd. June 28, 1948, No. 17334. [Class 75 (iv)] In an electric lighting fitting having a framework with a rectangular light-transmitting screen 6 mounted flush within its mouth, projecting locating means (conical headed bolts 8) are provided on the outer surface of the screen adjacent at least one pair of its parallel edges, and the extension N of the screen beyond the locating means is reduced to the minimum required to retain the screen within the framework, thereby allowing the screen to be removed through the framework mouth with a minimum of tilting. As shown a reflector 3, forming part of lighting fitting housed within a recess in a ceiling 1, has a rectangular rim 5 on which the screen 6 is supported along one pair of its edges. The locating bolts 8 are spaced along the screen and each has a cylindrical headportion 9, of slightly greater depth than the thickness of the rim 5, from which the conical head-portion extends, the lateral distance between the outer edges of the head-portions 9 being substantially equal to the width M of the reflector mouth. One or more bolts 8 may be attached to the reflector by a chain 10 to prevent accidental droppage during its removal. The screen 6 may be of glass or thermoplastic material and the locating bolts 8 may be replaced by V- section ridges formed on the screen. Alternatively the edges of the screen may be pressed upwardly and flanged outwardly to give a shallow-dish formation.