| 摘要 |
<p>372,248. Electric signalling systems. KIDDE & CO., Inc., W., 140, Cedar Street, New York, U.S.A.-(Assignees of Grant, H. C. ; 470, West 159th Street, Manhattan, New York, U.S.A.) Nov. 5, 1930, No. 33433/31. Convention date, Nov. 21, 1929. Divided on 371,954. Drawings to Specification. [Class 40 (i).] Relates to an electric signalling system, more particularly a fire-alarm system, wherein a plurality of circuits, each having a plurality of switching devices, e.g. protective devices, are arranged so that when any one of the switching devices is operated an indication of the affected circuit is given by a lamp. The system described is identical with that described in Specification 371,954, but the invention resides in the provision of supervising arrangements for the indicating lamps. Normally the lamps are connected in a series circuit including a relay which is released to operate an alarm in the event of the fault in the lamp circuit. When one of the signalling circuits is operated, a relay common to the lamps is operated to connect the lamps in parallel, the appropriate lamp being operated in a circuit closed by a relay individual to the affected signalling circuit. Specification 372,249 is referred to.</p> |
