IMPROVEMENTS IN FIRE ALARMS OR APPARATUS FOR INDICATING TO THE INMATES OF A BUILDING THAT A FIRE HAS BROKEN OUT THEREIN
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Peter Jensen at the Office of the
Commissioners of Patents on the 3rd May 1876. A communication from abroad
by Theodore Magnus Anglin, of Stockholm, Sweden, Engineer.
PETER JENSEN, of Chancery Lane, London. "IMPROVEMENTS IN FIRE ALARMS
OR APPARATUS FOR INDICATING TO THE INMATES OF A BUILDING THAT A FIRE
HAS BROKEN OUT THEREIN." A communication from abroad by Theodore Magnus
Anglin, of Stockholm, Sweden, Engineer.
The object of this Invention is to inform the inmates of a building that a fire has
broken out therein.
The apparatus consists mainly of an alarm clock in a box, which is placed in' the
sleeping room or other suitable part of a building. The clockwork is actuated by a
weight suspended in a thin metal wire wound on a drum, which by tooth wheel
gear is connected with an escapement or pawl wheel, and with a spindle carrying
the béll hammer. The pawl is connected to a two legged glass or metal thermo-
meter tube terminating in a ball filled with mercury and made so that it bursts
by a temperature of from, say, 70° to 120° Fahrenheit. When it bursts a spiral
spring connected to the glass tube is released and draws by means of levers and a
connecting bar or link the pawl away from its wheel, whereby the clockwork is set
going and the bell sounded. The mercury drops into a saucer below; this saucer
is placed on an arm, which draws the last named lever down, thus acting as a reserve
or further means to ensure the proper action of the alarm in case the first described
means are not strong or quick working enough.
For further security's sake an explosive appliance may be added to the apparatus.
In the drum a spring is fastened having a small projection or peg, which is opposite
a slot in the drum, and so long as the wire wound round the drum it is kept from
protruding through the slot, but when the weight drops down and the wire unwinds
so far that the said peg can pass out through the slot it pushes down the back end
of a pawl lever, the front end of which is then thrown up, thereby releasing a
small rod in a tube, a spiral spring then sending it sharply forward with the
end knocking against an explosive composition or percussion cap.
The alarm apparatus is by means of mechanical or electrical connection put in
communication with any desired number of the other rooms in the building, and in
cach such room is placed a similar but simplor alarm apparatus provided with a
tube with the parts belonging to it.

page_text: The mechanical connection for these simpler apparatus may be arranged as
follows-The double legged tube, the levers, and the spiral spring with arm aro
enclosed in a wooden box, and connected together as before described. When the
mercury globe bursts the mercury falls into the saucer on the lever, the spiral spring
presses simultaneously against a washer plate releasing the pawl lever, whereby the
weight puts a wheel in motion. On the drum of this wheel the one end of the
connecting wire is fastened, while the other is connected to the alarm apparatus.
The pawl is then released, and the bell begins to sound. The clectrical connection
may be made in any ordinary way.