GB644862A - Improvements in and relating to lighting fittings - Google Patents

Abstract

644,862. Projector lamps. GENERAL ELECTRIC CO., Ltd., and SMYTH, J. B. S. Nov. 11, 1946, No. 33427. [Class 75(iv)] [Also in Group XL(a)] A studio or stage lighting fitting employing a H.P.M.V. lamp comprises at least one pivotally mounted reflector normally forming part of the optical projection system of the lamp but which can be closed at least partly around the lamp during operation of the fitting to prevent escape of light and to keep the temperature of the lamp sufficiently high for the vapour pressure in the lamp to be maintained when the power supply is below the normal operating value. A H.P.M.V. lamp mounted on holders 3, 4 in a casing 1 has associated with it a system of reflectors 5-9 of which two 8, 9 can be rotated about axes parallel to the lamp axis by means of a lever 10 and links 11, 12. In the dotted position of the pivoted reflectors shown in Fig. 2 the lamp is completely enclosed. A snap action is given to the operating mechanism by springs 13, 14 and stops may be provided to locate the pivoted reflectors. When the reflectors are closed around the lamp the power to the lamp is reduced by inserting a resistor into the electrical circuit either by manual or automatic switching and an interlock mechanism including a relay having an operating coil across the lamp may be provided so as to prevent the pivoted reflectors from being opened and the power to the lamp increased until the voltage across the lamp has reached a predetermined value. Means preventing the main supply from being switched on when the pivoted reflectors are in the open position may be provided. The ventilation to the lamp may be cut off when the reflectors are closed. Ancillary electrical equipment is contained in a housing 15 under the casing 1. Specifications 573,590, 574,135, [both in Group XL], and 644,876 are referred.