others
Year: 1886

page_text: I, EDWARD GRIFFITH BREWER of 33 Chancery Lane in the County of Middlesex
Fel. Inst. P.A. do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statemont :-
My invention relates to improvements in burglar and other alarm bells, and refers
to the construction and application of an alarm bell which rings when a key or other
object is placed in the keyhole of a door to which the alarm may be fitted, and thus
warning is given that some one is trying to enter a house, or room, or is attempting
to open a safe or other place, as the case may be.
The invention also refers to a construction of alarm apparatus in which the bell is
contained within such apparatus and is acted upon directly by the introduction of the
key or other object, and also of an alarm apparatus which sounds a bell at a distance
for example by electricity or by any simple mechanical means.
According to the invention the alarm bell is sounded by means of clockwork or
springs acted upon by the lifting up of the latch. This lifting up of the latch takes
place when the key or other object is introduced or pushed in the keyhole of a door to
which the alarm apparatus is fitted.
The raising of the spring causing the alarm to sound is effected by the withdrawal
of a hook or catch on the face of a toothed wheel actuating the main spring of the
mechanism, the withdrawal of this hook or catch is effected by the introduction of the
key in the keyhole; which there acts upon a jointed arm or lever carrying at its free
end a screw which is at right angles to it and which is placed in the keyhole. When
the alarm is not required to be sounded the said screw is unscrewed sufficiently to
allow its end to be free of the keyhole.
I will now describe the invention with reference to the accompanying drawings of
which Figure 1 is a front view of the apparatus; Figure 2 is a front view of the

page_text: apparatus with the bell removed, showing the mechanism for working the hammer G
each time the door is opened; Figure 3 is a front view of the apparatus with the
plate B removed, showing the interior of the box containing the mechanism which
works the hammer G¹ when some one tries to pick the lock; Figure 4 is a plan of
Figure 1; Figure 5 is a sectional plan showing the two mechanisms, and Figure 6
is a side section through the centre of the apparatus and showing the spring arrango-
ment for working the hammer G'.
;
A is the bell, B the closing plate of the box B' holding the mechanism employed to
work the hammer G', B¹ the box either of cast or sheet iron, in one or more parts
containing the mechanism working the hammer G'; C is the screw introduced in the
key hole D lever working the mechanism of the hammer G; E is a tumbler acting
upon the knee piece by means of a spring and thus causes the hammer G to
strike. By means of spring F1 ácting upon tumbler E the lever D is brought back to
its normal position; F is the spring working the hammer G; F¹ is a spring bringing
the lever D and the tumbler E back to their original position after the hammer Ghas
struck; G hammer which strikes the bell each time the door is opened; G¹ the
hammer which strikes the bell when anyone tries to pick the lock; g is a steel wire
attached to the plate B and acting as a spring to prevent the hammer G¹ remaining
against the bell; H is the lever carrying the screw C and which may be turned back
on the lever I when the alarm is not wanted to work; I the lever jointed to the
lover H aforesaid and formed with a hook at its end in the box B¹ against which hook
the pins a on the wheel Q strike; J is the fulcrum of the lovers IH; K is the key-
holo in which the screw C is inserted; L is the door; M a hollow shaft rivetted or
fixed to the plate B, and carrying the bell A; M' is the axis of the spring Z'; Nis the
key for winding up the spring; O a lever which the pins a, a cause to rock when the
wheel Qturns, and which lever ☐ acts by means of a cord or a wire upon a boll
placed on the floor or close by; P the knee piece which carries the hammer G; Qis
a toothod wheel with tooth of a special form acting on the "pallet" T R a pawl
acting upon the ratchet wheel Z; S is a spring holding the pawl R against tho
wheel Z T is the "pallet" working the hammer G'; T' is the axis of the "pallet " T
carrying the stem or arm of hammer G₁; U is a spring which presses the lover I'
against the wheel Q; V is an armature opening and closing the circuit; V' a piece
of ebonite insulating the terminal Y; X is a box containing the spring ; Y Y are
the electric terminals; Z is the ratchet wheel fixed to the axis M¹ of the spring Z,
and Z is the spring revolving the wheel Q when the lever I is disengaged from
the pins a.
The action of the apparatus is as follows:-
When the end of the screw C is placed in the keyhole to prevent the lock being
picked as shown in Figure 3, the apparatus is ready to work; so that if a key, wire
or other instrument is introduced from the outside the screw O is pushed forwards
and the levers H and 1 1 will turn on their fulcrum J and will be disengaged
from the pin a and the alarm will sound. As may be seen by reference to Figures 3
and 5 of the accompanying drawings, the pins a, a, a, a butt against the hooked
end of the arm or lever 11' and thus stop the movement; but when the lover or
arm turns on its fulcrum J it leaves the pin against which it rests and the
wheel is free to turn by means of the spring 7. In turning, the teeth of
the wheel meet the ends of the "pallet" T which engages alternately between
said teeth. The rotary motion of the wheel Q communicates a to and fro motion
to the pallet T which to and fro motion is then communicated by the axis of pallet T
to the arm of the hammer G₁ acting on the bell A. When the wheel Q turns the
pins a meet the lever O which, pivotting on its axis, works by means of cords
or wires a bell placed on the floor or on the wall of the room in which it is desired
to prevent an entrance, or in any other convenient position or place. The object
of this arrangement is to give warning that someone is trying to enter such room.
To sound an alarm from a distance it is found that the employment of the lever O
requires too much power there being so much friction of the wire or cord against
the walls, and round corners, an electric connection is therefore added to this alarm

page_text: apparatus working on a bell placed where most convenient and which will sound
an alarm at a very great distance when the lever I is acted upon.
As shown in Figure 1, the apparatus consists of a bell having an arm H projecting
from its side, which arm H carries at its extremity a trigger screw C forming the
trigger which is placed in the keyhole and is encountered by any instrument
introduced into such keyhole. The arm H forms the continuation of the hooked
arm II' which is constructed to receive at its extremity the joint of the arm H. It
will be easily understood by referring to Figure 3, that when a key or other
instrument is placed in the keyhole K, the arm H being pushed away from keyhole
will force the hooked lever I I¹ in a horizontal direction sufficiently to disengage
such hooked lever from the catch a of the wheel Q against which it is till then held,
and thus the alarm bell will be caused to sound as long as the pressure is continued.
It is not necessary to describe particularly the parts forming the mechanism
above described as such parts are well known in the construction of clockwork
mechanism, but that which is new in this invention is the employment of an alarm
bell in combination with the arm H provided with a screw C which screw C is placed
in a keyhole so that the bell is caused to sound when a key or other instrument
is introduced into such keyhole as above described.
One part of this invention consists in the application to the said alarm bell of
an electric circuit, such circuit being broken or completed by the action of the
armature V. The hooked lever. I I¹ presses when it is acted on by the arm H against
such armature V and thus completes the electric circuit through the wires passing
from the terminals Y Y¹ to the alarm bell; and the alarm is thus sounded.
This invention then consists of an apparatus in which an alarm bell is combined
with an arm caused to act by the pressure of a key or other similar instrument
against a projection formed on such arm.
When desired this alarm apparatus can be disconnected by simply drawing
back the projection placed in the lock and folding back the front end of the aforesaid
arm H which is jointed for the purpose as before described. This apparatus can
also be employed as an ordinary bell by connecting a cord with the lever D and
the door handle so that as the handle is turned and the door opened the lever D sets
off the alarum. It can also be arranged to give the alarm to the upper or lowor
stories of a house by a mechanical connection caused to act at the same time that the
apparatus is set in motion by the key.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim as
the invention communicated to me is :-
First: In burglar and other alarm bell apparatus the construction and application
of an alarm bell having combined therewith the arm H from which arm H projects
the screw C, substantially as and for the purposes hereinbefore set forth and
described with reference to the accompanying drawings.
Second: The application of an electric circuit to burglar and other alarm boll
apparatus substantially in the manner and for the purpose hereinbefore set forth.
Third: The general construction arrangement, and application of burglar and
other alarm bell apparatus substantially as hereinbefore set forth and described with
reference to the accompanying drawings.
BREWER & SON,
For the Applicant.