Patent GB-415246-A (GB)
Title: Improvements in or relating to electrically supervised indicating or alarm and control systems
IPC: G08B29/02
Filed: 1933-07-04
Abstract: 415,246. Indicating position of doors. GWATKIN, F. A. S., 31, Basinghall Street, London.-(Garrison Fire Detecting System, Inc. ; 307, 5th Avenue, New York, U.S.A.) July 4, 1933, No. 18993. [Class 65 (i).] Relates to electrically-supervised fire-alarm and control systems for the protection of public and private institutions, and is described as applied to the protection of a penal institution, Fig. 1, comprising halls on the first and second floors with rooms having doors D. Separate thermo-sensitive cables C<1>, C<2>, each having a fusible conducting core which makes contact with an outer conductor when melted, are carried respectively around the first and second floors ; the conductors of each cable can be connected by a hand alarm switch N. The cables are associated with secondary circuits which, in case of fire, actuate audible and visual alarms, switch on an emergency lighting system F<1>-F<6>, release the latches 160 of the doors D, and signal to a warden when the doors of all the occupied rooms have been opened to allow escape of the inmates. Means are also provided to indicate if any single door is opened at any time. All the circuits are self-supervised. A system of lamps and bells on panels P, P<1> arranged respectively inside and outside the building conveys the desired alarms and indications to the warden and to persons outside. To indicate when all the doors have been opened, after release of the latches, each door has associated with it a switch, shown as S<2> on the first floor, Fig. 1, and S' on the second floor. Each switch comprises a spring plunger which holds apart contacts so long as the door is closed, but permits the contacts to engage and close circuit when the door is opened. All the switches S<2> are connected, as shown in Fig. 3, in a circuit 60, 61 which includes relays R', R<8>. Resistances 59 across the switches maintain in the circuit a current sufficient to actuate relay R' but not relay R<8>. The relay R<8> is only actuated when all the resistances 59 have been shunted by the closing of all the switches S<2>, i.e. by the opening of all the doors D. When so actuated, its armatures 62, 63 effect the lighting of lamps L<5>, L<6>. Similarly, the switches S<3> effect the lighting of lamps L<7>, L<8> through a circuit including relays R<9>, R'‹. The switches S<2>, S<3> are provided with jack terminals 73 for co-operation with a manual jack, whereby the warden may cut out the switch of any room which is unoccupied. A fault in either circuit causes de-energization of relay R<7> or R<9>, resulting in lighting a lamp L<16> and sounding a bell (not shown) connected to the conductor 91. The lamps L<5>, L', which are arranged on the external panel P<1>, are normally supervised in series with fire alarm lamps L<1>, L4 by a relay R<15>. This is connected in a circuit including the armatures 21 and 22 of a fire alarm relay R<3>, the filaments of the lamps, and armatures of the relays R<8>, R<10>, the current being insufficient to light the lamps. A fault in this circuit causes de-energization of the relay R<15>, resulting in the actuation of a lamp L<18> and the fault bell mentioned above. For providing a signal when any single door has been opened at any time, each door has associated with it a switch S<4> similar to the switches S<2>, S<3>. All the switches S<4>, Fig. 5, are connected across a circuit which includes a resistance 76 and relays R", R<12>, the relay R" normally being energized and the relay R<12> not energized. The opening of any door short-circuits the resistance 76, so that the stick relay R<12> is energized. When so energized, it actuates, through its armatures 77, 79, a lamp L<9> and a bell B<4>, which remain energized, even if the door which was opened is immediately reclosed, until a switch S<5> is operated to open the stick circuit of the relay R<12>. With this switch in the " off " position for the stick circuit, a lamp L<10> is lighted to give warning that the indication arrangements are not complete, although an indication will still be given so long as a door is open. A fault in this circuit causes de-energization of relay R" resulting in the actuation of a lamp L<17> and the fault bell. A relay R<16> with watching- current resistance 126 is connected in a circuit including the winding of bell B<4>. A fault in this circuit causes de-energization of relay R<16>, resulting in the actuation of a lamp L<19> and the fault bell. Energization of relay R<12> by the opening of any door D acts to shunt the relay R<16>, so that both bells sound if any door is opened. Failure of the battery causes de-energization of a relay connected across it, to energize a lamp and a bell by current derived from an auxiliary battery. The latter is normally similarly supervised by a relay connected across it, the indication circuit of this relay being fed from the main battery.