GB785123A - Electric light units for use in aircraft - Google Patents

Abstract

785,123. Electric battery lamps. WILMOT-BREEDEN, Ltd. Jan. 5, 1956 [Feb. 10, 1955], No. 3987/55. Class 39(2) [Also in Group XXXVII] A battery lamp for use as an emergency light in aircraft, and adapted to be switched on automatically in the event of a crash comprises a body part 1 formed with a chamber 2 for a battery 3 and lamp bulb 7, and an inertia switch within the body part and connected in the lamp circuit, the said switch comprising a spring- loaded plunger 12 carrying a contact 13 which is normally held apart from an adjacent contact 14 by a weighted member 21 arranged to obstruct movement of the plunger until displaced as a result of the impact of a crash, whereupon the spring 16 within the plunger 12 acts to close the contacts 13, 14. In the example the weighted member 21 is displaceable laterally relative to the plunger by mounting it on the lower end of a stem 22 formed with a spherical protuberance which engages within a part spherical seating in a block 24, the upper end of the stem being extended so that it has free angular movement within a hole in the cover 11 of the unit. The bottom end of the weighted member 21 is formed as a conical or otherwise shaped projection adapted to engage within a recess in the upper end of the plunger 12 in order to maintain the switch contacts open. As shown the weight 21 can be displaced laterally from the plunger in any direction. Alternatively the stem could be pivoted for angular movement only in the plane extending fore-and-aft of an aircraft in which the lamp is fitted. The switch can be reset manually to the open position by manipulating the end of the stem 22 which projects through the cover 11. The electrical connection between the bottom terminal of the battery 3 and the plunger 12 comprises a spring 6 attached to a plate 19 provided with a pair of resilient blades 18 which grip between them the lower end of an adjustable plug 17 screwed into the bottom of a cylindrical guide 15 for the plunger. The compression of the spring 16 can be adjusted through a hole in the bottom 4 of the body of the lamp. The fixed contact 14 of the switch abuts against a metal reflector 9 carried by a transparent or translucent plastic closure member 10 provided with a screw-threaded skirt engaging within a hole in the cover 11. The lighting unit may be detachably mounted and secured within a socket 27 by providing the body part 1 with bayonet-joint slots which receive pegs 26 secured on the socket.