GB742396A - Electric impulse lamp as transmitter for light-flash signalling system - Google Patents

Abstract

742,396. Discharge lamps. FRUNGEL, F. Dec. 18, 1952 [Jan. 2, 1952], No. 32100/52. Class 39 (1). [Also in Groups XI, XXXVIII and XL (b)] In a system for indicating to the driver of a leading vehicle when a following vehicle desires to overtake the following vehicle is provided with a spark gap which is broken down by a condenser discharge to produce a light pulse having characteristics which are recognizable by photo-electric apparatus which is carried on the leading vehicle. As shown, the spark gap is enclosed within a sealed glass envelope 1 which may have a filling of rare gas and is situated in front of a reflector 2. To the rear of the reflector are a pair of disc type condensers 3 connected in parallel with the spark gap by leads which are as short as possible to keep down their inductance. The other contact to the condenser may be effected through the parabolic reflector which may be silvered. Behind the reflector is situated an induction coil 4, the primary of which is supplied from a battery. A contact 5 is broken by the magnetic field of the core when the primary current reaches a prearranged value. An' arrangement is described in which condenser 3 is constituted as insulated foils wound around the induction coil. In the arrangement of Figs. 4 and 5 (not shown) the spark gap is provided with its own reflector which is mounted inside a headlamp together with the incandescent lamp. In the arrangement of Fig. 6 (not shown) the reflector of the lamp is provided with a socket to receive a plug attached to the auxiliary reflector. The auxi liary reflector may be eliminated if a recess for the spark gap is provided in the main reflector. In the arrangement of Fig. 8 the spark gap 21 and incandescent lamp filaments 22, 23 are mounted in the same envelope. Electrode 25 is supported by the anti-glare baffle 24. The electrode which has a common connection with the filaments is made the positive connection of the spark gap. This ensures the development of the full breakdown potential at the spark gap. The electrodes are made of materials which may be spattered on to the filaments without affecting their emission. Tungsten, tantalum and molybdenum are said to be suitable. Specification 719,356 is referred to.