GB587036A - Improvements relating to testing devices for electric circuits - Google Patents

Abstract

587,036. Battery lamps combined with current and fault detectors. CHADWICK, A. June 11, 1945, No. 8768/44. [Class 39 (ii)] [Also in Group XXXVI] A combined torch and tester for continuity or liveness of a circuit comprises a neon test lamp, battery, torch bulb and switch therefor carried within a casing, the switch comprising a part of the lamp or a separate casing therefor and test leads being wired across the switch. As shown, a tubular metallic casing 1 houses a torch bulb 4, dry battery 5 and neon test lamp 7. The lamp 7 is mounted in a transparent casing 8 carried by a cap 10 secured in the end of casing 1 by a bayonet joint so that a coil spring 3 is slightly compressed thereby producing good electrical contact between the bulb 4 and battery at 6 and between the other end of the battery and the end cap 8a of casing 8. The terminals of the neon lamp 7, visiblethrough apertures 12 in casing 1 are connected respectively to the end cap 8a and to a socket 10a. For testing a line for "liveness," a lead (not shown) connected to the socket 10a, is applied to the line by means of a test prod such as 19. glowing of the neon lamp indicating "liveness" provided the line voltage is great enough. For continuity tests leads 17, 18 secured to a spring clip 16 detachably carried by the casing 1 are used. The lead 18 is electrically connected to the clip and through it to the casing 1; the lead 17 is insulated from the clip and ends in a contact 21 projecting through a hole 13 in casing 1 to contact with the end cap 8a. A second hole 13 is provided through which the tip 14 of spring 15 may be depressed to contact the end cap 8a to light the bulb 4 when the apparatus is being used as a torch. The leads 17, 18 are thus connected across the switch 15 and continuity of any conductor to which the test prods 19, 20 are applied is indicated by lighting of bulb 4. The spring 15 may be used as a pocket clip or a separate clip may be provided. Other types of switch contact may be used in lieu of the spring 15, and the spring-on clip 16 may be replaced by other types of detachable connection, e.g., a two-pin plug and socket; or the leads 17, 18 may be permanently secured to their respective parts wrapped around the casing 1 and the whole then secured in an outer casing. The lead 18 may be dispensed with, the casing 1 being used in lieu as the contact.