IMPROVEMENTS IN FIRE ALARMS FOR SIGNALLING AND COMMUNICATING BETWEEN CERTAIN STATIONS, PLACES, OR BUILDINGS THE OUTBREAK OF A FIRE
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Charles Spratt at the Office of the
Commissioners of Patents on the 1st March 1881.
1
CHARLES SPRATT, of 5, Elizabeth Villas, Coplestone Road, Peckham, in the
County of Surrey. "IMPROVEMENTS IN FIRE ALARMS FOR SIGNALLING AND
COMMUNICATING BETWEEN CERTAIN STATIONS, PLACES, OR BUILDINGS THE
OUTBREAK OF A FIRE."
First. An arrangement to be worked by any person or persons wishing to send an
alarm to the nearest fire brigade station.
Second. An arrangement to be used only by the firemen or by some other
appointed persons to communicate any message to the fire brigade station.
My first arrangement whereby any person or persons can send an alarm to the
nearest fire brigade station by simply turning a handle or by pulling out or by
pushing in a handle inserted in a pillar post or in a box fixed in a wall, which
aforesaid handle turns a pinion gearing into a toothed wheel revolving on a centre
fitted into a metallic plate but insulated from it, the aforesaid plate having a certain
number of projections or pins, so that when the aforesaid pinion is caused to be
turned, the aforesaid centre having an arm passing over the aforesaid projections or
pins, thereby making a number of electrical contacts corresponding to the aforesaid
number of projections or pins, each projection or pin representing a certain station
or call post, so that when the aforesaid centre with arm has travelled over a certain
number of projections or pins it is brought to a standstill automatically at the one
which represents the station or call post from which the alarm was sent, thereby
causing the index on the dial of the receiving apparatus situated at the fire brigade
station to point to the name of the station or the call post from which the alarm
was sent. A small galvanometer of simple construction will be placed in the
electrical circuit at each station or call-post to show when signals have been received
and also to test the line.
The open circuit system is adopted, worked by one battery at the fire brigade
station. The key to open the aforesaid apparatus will be kept in a recess closed by
a small glass similar to that of a watch. It must be broken to obtain the key;
spare glasses are kept to be replaced at once by firemen, policeman, or other
persons.

page_text: The receiving apparatus consists of an electro-magnet which works an armature
in connection with improved pallet and check pawl, rendering its action certain,
and propels a wheel on which is fixed an index, which index travels round a dial
graduated alphabetically and also named according to the place and number of
alarms required, so that when an alarm is given a continuous bell is rung by its
circuit being closed at the first dip of the aforesaid armature, the aforesaid index
being carried round the dial stopping at the name of the station, place, or building
from which the alarm was sent and nearest to which the fire is situated.
All messages are received upon the dial on the step-by-step principle as in the
"A, B, C," instruments.
My second arrangement, to be used by the firemen or by some other appointed
persons to communicate any message to the fire brigade station, is arranged on
nearly the same principle as the "A, B, C," instrument now being used by firemen,
and is placed at the station or call-post in connection with my first arrangement
but accessible only to firemen or other appointed persons.