AN IMPROVED ALARUM FOR PUBLIC AND PRIVATE BUILDINGS, BANKERS' STRONG ROOMS, SAFES, AND OTHER DEPOSITORIES INTENDED TO CONTAIN VALUABLE PROPERTY AND DOCUMENTS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Charles Heirons at the Office
of the Commissioners of Patents, with his Petition, on the 30th
November 1870.
I, CHARLES HEIRONS, of Plumstead, in the County of Kent, do hereby
declare the nature of the said Invention for "AN IMPROVED ALARUM FOR
PUBLIC AND PRIVATE BUILDINGS, BANKERS' STRONG ROOMS, SAFES, AND OTHER
DEPOSITORIES INTENDED TO CONTAIN VALUABLE PROPERTY AND DOCUMENTS," to be
as follows:-
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This Invention consists in constructing alarums and operating there-
with in the following manner :-Into a circular-shaped vessel, say nine
inches deep by four and a half inches in diameter, closed at the bottom
and open at the top, I place loosely another similarly shaped vessel in
an inverted position, namely, with its open end downwards. This inner
vessel I fit with a flap valve of leather or other suitable material to cover
an opening made in the top of the said inner vessel. I also fix to the
outside of the top of the said vessel a small vulcanized india-rubber tube
to establish a communication between the inside of the said inner vessel
and a chamber to which the opposite end of the said tubo is fixed or

page_text: connected, as presently described. I also fix a tube to the centre and
inside of the aforesaid outer vessel at the bottom thereof, the said tube
passing out through the side of this vessel to carry off water from this
vessel after it has been filled therewith about half full. The top of the
aforesaid outer vessel I fit with a loose lid with a hole therein for the
aforesaid india-rubber tube to pass through; and to this lid I affix a bell
and hanmer operated upon by a spring and clockwork for sounding an
alarm. I also connect the top of the aforesaid inner vessel by a cord
passing through a hole in the lid of the outer vessel by means of a
pulley fixed to the said lid, and to the other end of the said cord I affix
a weight sufficiently heavy to counterbalance the weight of the inner
vessel; and immediately beneath the bottom of the said weight I adjust
one end of a lever of the first order, the opposite end of the said lever
being so formed and adjusted as to keep the hammer out of contact with
the bell when the alarum is out of action. The alarum thus constructed
I propose to connect to a window or door by the following means:—
For the purposes of this Invention it is necessary to make the doors
and windows double, so as to leave an air-tight chamber between the
two; for example, instead of having only one pane of glass as commonly
practised in sashes, I propose to have a second pane behind the ordinary
pane, the chambers thus formed in each sash communicating with each
other. Through the meeting rail of each sash I form a vertical hole,
over which I fix a piece of brass having a hole also made in it, and
communicating with a horizontal hole, into which I fit a short piece of
metal tubing open at one end, and with an opening in the side to corre-
spond with the aforesaid vertical opening, and over the open end of the
aforesaid short tube I pass the end of the before-mentioned vulcanized
india-rubber tubing, and by means of a thumbscrew fix the metal tube in
the before-mentioned piece of brass, and by these means I establish a
communication between the chambers between the panes of glass and
the inside of the aforesaid inner vessel, and this applies to the chambers
of doors made by lining them with sheet metal or otherwise.
The operations of an alarum constructed and arranged as above
described are as follows:- Suppose the apparatus to be charged with
water, any air that may be in the inner vessel will pass out by the valve
thereof. The clockwork being also wound up the alarum is ready for
use, and operates as follows:-Suppose a burglar to cut a hole in any of
the panes of glass or panels of a door or fan light to which the alarum

page_text: is connected the effect will be to admit air into the aforesaid chambers,
and the air thus admitted will enter the aforesaid inner vessel and lift it
similar to the action of a gasometer; the weight connected thereto will
thus be lowered, and acting on the lever beneath will release the hammer
and allow it to strike the bell, which it will continue to do during the
descent of the weight, which may be for some minutes, thus giving an
alarm to the inmates of a house or building. The mechanism of the
alarum may be placed in any room of a house distant from the window
or door thereof, or strong room when applied to a banking house.
In adapting this Invention to iron safes not set in a wall I propose to
cover the safe with a loose air-tight case of sheet metal, the bottom
edges whereof are sealed by dipping in a trough of water at the bottom
of the safe. The before-mentioned india-rubber air tube is fixed to
the outside of the safe at the back or side thereof, so that when the
outer case is passed over the safe no air can pass through the tube into
the alarum, but immediately the case is raised the air passes into the
alarum and causes the bell thereof to be sounded.
The above principle of constructing alarums may be applied to bells
placed at the outside of buildings to sound an alarm.