An Improved Electrical Burglar Alarm.
Year: 1891

page_text: Date of Application, 25th Feb., 1891
Complete Specification Left, 4th Nov., 1891-Accepted, 12th. Dec., 1891
PROVISIONAL SPECIFICATION.
An Improved Electrical Burglar Alarm.
I ARTHUR ERNEST SPENCER of 5 Park Avenue Road Park Tottenham in the
County of Middlesex Electrician do hereby declare the nature of this invention to
be as follows:-
My invention relates to electrical burglar alarms and particularly to those
employed for automatically giving warning, when a burglar enters through the
window.
The electrical devices are arranged in such a manner, that when the blind is
down, no stranger will be able to touch it, without giving the alarm.
In practically carrying out my invention, I require an ordinary electric battery
and alarm bell or gong. (It will be understood, that where such battery and bell
installation is already provided in a house, I can easily connect my alarm with it.)
My alarm is constructed of a square piece of wood, vulcanite or any other hard
nonconducting material suitable for the purpose. On two opposite sides of this
square piece, I fix by means of screws, a thin piece of steel, or other suitable metal,
which, a little way over the top of the square bottom piece, I bent inwards near the
free end, in such a manner, that the two pieces meet and form a clip. One screw on
each side is destined to receive the connecting wire (communicating with the bell
or gong).
Through the centre of the square bottom piece, I drill a hole, so that by means
of a screw, I may fix the alarm to any suitable part of the window frame.
A flat wedge (preferably of triangular shape) made of wood, vulcanite, or other
suitable nonconducting material, engages in the clip, which holds it fairly tight.
By means of a cord or other suitable arrangement this wedge is fastened to the
blind, when the latter is pulled down. The blind thus directly connected with the
alarm will when touched, pull out the wedge immediately, whereby the clip will
close (ie. the two pieces of metal will touch) thus making contact and the bell or
gong will be started.
Dated this 24th day of February 1891.
CHAS. W. J. NOLTE,
17, Coleman Street, E.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improved Electrical Burglar Alarm.
I ARTHUR ERNEST SPENCER of 5 Park Avenue Road Park Tottenham in the
County of Middlesex Electrician 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 statement :-
My invention relates to electrical burglar alarms and particularly to that class,
which are employed for automatically. giving warning, when a burglar enters
through the window.
The electrical devices are arranged in such a manner that when a blind is down,
no stranger will be able to touch it, without giving the alarm.
In practically carrying out my invention I require an ordinary electric battery
and alarm bell or gong. (It will be understood that where such battery and bell
installation is already provided in a house I can easily connect my alarm with it).

page_text: I will now refer to the annexed drawings in, which
Fig. 1, shews a side view of my alarm.
Fig. 2, a a side view of a modification.
Fig. 3, a front view of same and
Fig. 4, a front view of another pattern.
The apparatus, as shown in Fig. 1 consists of a piece of wood, or other suitable
materiai A provided with a hole through which a screw or nail is passed into a
suitable spot at the window. Fixed by means of screws S are two thin pieces of any
suitable metal, shaped so as to form a clip, which receives the wedge W. This
wedge is made of vulcanite or any other nonconducting material and is destined to
break contact, it is V shaped and is provided with a cord or piece of wire C.
When the blind is pulled down this cord is attached to it, so that anybody pushing
against or trying to raise the blind from the outside, will pull out the wedge, thus
allowing the two pieces of metal to touch and form contact, whereby the alarm bell
or gong will be set in motion. The screws S. hold the wires E which are connected
with the bell or gong.
In Figs. 2 and 3 a modification of above is shown.
piece of wood (or other suitable material) is partly covered with a piece of suitable
metal b. The spring holds the wedge W. Between this spring and the metal
part a piece of vulcanite V (or other suitable nonconducting material) is fixed so
as to prevent the two, metal pieces from touching at that point. The wires are
held by screws S and S', when the wedge is pulled out, contact is made. Through.a
hole a screw or nail is passed to fasten the apparatus to the window.
The
In Fig. 4, another modification is shown, instead of having a square block I
employ a round one, a semi-circular piece of metal forms, in connection with
spring, contact, when the wedge is withdrawn the. screws S, S, S', serve not alone
to hold the wires and fasten down parts b and f, but also for fastening the alarm to
the window.
I have here shown three of my designs only, but several other modifications may
be employed, all within the scope of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
(1) An improved burglar alarm which when attached to the window and blind in
the manner hereinbefore described gives the alarm, as soon as somebody pushes
against or raises the blind.
(2) For burglar alarms, the special constructions of the apparatus in which by
pulling out a V shaped wedge from between the spring clip f f (Fig. 1) or a
spring and a metal-piece b. (Fig. 2. 3 and 4) contact is made substantially as
described hereinbefore with reference to the annexed illustrative drawings.
Dated this 28th day of October 1891.