Patent GB-190314269-A (GB)
Title: Improvements relating to Electrical Fire Alarms and other Electrical Signalling Systems.
Inventor: PULFORD EGERTON GOOLDEN
Filed: 1903-06-27
Granted: 1904-09-27
Abstract: 14,269. Pulford, E. G. June 27. Signals, i n d i - cator or visible, electric - bell, a n d electric-lamp; indicators or annunciators.-Relates to non-automatic electric fire-alarm or signalling systems having normallyclosed circuits, applicable for buildings and streets, and other signalling purposes. A circuit 1, Fig. 1, proceeds from a central-station battery 10 to a lowresistance relay 4 fitted at a warehouse &c. and controlling local alarm bells ; thence the circuit passes through alarm boxes 2 connected in series and normally shortcircuited, and returns to the central-station switchboard, its ends being provided with lightning arresters. At the switchboard, the circuit 1 passes through low-resistance coils 12 of an indicator 7, thence by a key 8 to a high-resistance relay 9 and high-resistance coils of indicator 7 connected in parallel, and finally to the battery 10. The relay 9 thus holds its armature out of contact with the terminals 52, 53, and the indicator 7 points to "ready." Each alarm box comprises a plunger 17, Fig. 5, normally pressed by a spring 18 against a glass panel 15 and released when the panel is broken. A short circuiting device 24 is then opened, and an arm 22 freed to allow a weight 23 to descend and actuate a crown-wheel 28, Fig. 1c, which alternately releases and presses a spring against a contact 80. When the weight has run down, it closes a spring 81 and short-circuits the box. The current therefore excites the relay 9, Fig. 1, and closes the contacts 52, 53 as many times as there are gaps in the wheel 28. These gaps differ in number with each box. A current from a low-resistance battery 55 then passes by a spring 51, contact 52, and key 58 to electromagnets 57 and by a switch 56 back to the battery, the magnets 57 actuating a pawl 61 and turning a wheel 60 one tooth for each gap of the wheel in the alarm box. A pointer 64 is thereby moved over a dial to a division indicating whence the alarm came. An alarm bell 65 at the station is also actuated by the armature 59 closing the contacts 66 and completing the circuit of a local battery 67. The station attendant then signals back by pressing the keys 8, 58 on their back stops, thus disconnecting the magnets 57 and sending a strong current from the battery 55 via contact 53, switch 70, and the key 8 to the line 1 and low-resistance winding of the indicator 7, the pointer of which is brought to " reply received." A bell 71, Fig. 5, in the alarm box is rung, and a lamp 73 lighted by the same current, illuminating directions on a dial 72 ; the relay 4, Fig. 1, is also actuated and closes the local circuit of the alarm bells 6. If a wire breaks, or a false alarm is sent by the current weakening, the indicator 7 moves to "out of order," and the pointer 64 moves to the first division marked "fault." The bell 65 also rings, but the relay 9 is disconnected by switches 56, 70. The system may be tested by disconnecting the switch 70 and manipulating the key 8 to bring the pointer 64 to zero, or by a telephone jack 75, Figs. 1<c> and 5, the circuit to the permanent telephone 77 at the central station being completed through the earth. In a modification shown in Figs. 2 and 4, applicable for streets, each alarm box has a repeating- action operating in the same manner as the magnets 57 and scape - wheel 60, Fig. 1, combined with a longdistance switch 135, Fig. 4, an electric lamp 104 and a bell 106 for night and day use respectively, a line condition-indicator 107, Fig. 4<a>, relay 108, dial 109 corresponding to the dial 110, Fig. 2, at the central station, a telephone 111, and weight-operated crown-wheel, as before. The boxes are connected in series on one side and in parallel on the other, the wire 113 passing from the battery 120 to the low-resistance coils of the indicators 116, 110, key 117, relay 118, and shunt coils 125, Fig. 4, of indicator 116, both of high resistance and connected in parallel, and back to the battery 120. If the current is broken, the armatures of the coils 125 fall and expose the words "out of order"; the relay 118 also completes the local circuit of the receiver. The plunger 17, Fig. 2<A>, may be locked by means of a spring catch 83 and released by a cord or magnet 85. The escapement paddle may be controlled by an electromagnet. An alarm may be given and reply received as described above, or the telephones 111, Fig. 4, may be used. The pointers 131 in all the boxes are returned to zero simultaneously by the attendant at the central station continually tapping the front and back contact key 129, Fig. 2. Communication may be established between the central station and any box by tapping the key 117 to bring the pointer 132 to the required division ; the switch 135, Fig. 4, of the particular box is thus closed, and a strong current sent from a battery 137, Fig. 2, by closing the switch 136, the relay 108, Fig. 4, releasing the shutter 140 and lighting the lamp 104 through the earth circuit. The local attendant then replaces the shutter 140, thus breaking the earth circuit through the indicator 138, Fig. 2, and showing " man attending." The telephone 111, Fig. 4, may then be used. Fig. 3 shows nine boxes arranged in three sections so that any section may be short-circuited by means of a switch 144, if a fault arises. The faulty box may then be discovered by means of a switch 146 shunted across the main circuit.