GB393721A - Improvements in electric lamp fittings of the flame-proof type - Google Patents

Abstract

393,721. Flame-proof electric lamps. MAXLUME LIGHTING & HEATING CO., Ltd. and FORTH, J. W., Plume Works, Aston, Birmingham. March 19, 1932, No. 8192. [Class 75 (iv).] In a flame-proof electric lamp an internal switch is operated by an external member which is associated with a separate key and with the means for detachably attaching the globe holder to the lamp head so that the said means is positively covered against the key when the switch is in the " on position and can be operated by the key only when the switch has been hand moved to the "off" position. In the form shown the dolly a<2> of a tumbler switch a is connected by an inner arm d to a two-part rocker shaft e having an angular-sectioned end e<2> of one part engaging a slot in the end of the other part. This shaft passes through a bearing in the lamp head x and is fixed to an outer arm f carrying an imperforate portion f<2> and a portion having an aperture f<3> and a shoulder f4. The upper end of the screw-box g<2> is covered by the part f<2> when the switch is " on and by the aperture f<3> when the switch is "off." A separate key i is adapted to be inserted sideways in the aperture f<3> and has a squared socket i<2> to engage over the squared end g<3> of the screw box g<2>. By this means the screw box can be raised out of engagement with the screw pin g carried by the flange h<2> of the globe holder h and the globe z removed to give access to the bulb y. In the disengaging position the upper end of the screw box is maintained in engagement with the socket i<2> by the spring j and thereby prevents the removal of the key and ensures that the switch cannot be moved into the " on position whilst the globe is removed.