Improvements in or relating to Electric Burglar-alarms and the like.
Year: 1895

page_text: Date of Application, 18th Oct., 1895-Accepted, 4th July, 1896
COME DETE DE MULTICATION.
Improvements in or relating to Electric Burglar-alarms and
the like.
A communication from RAYMOND DAMBEAUX, Electrical Engineer, of Gembloux,
in the Kingdom of Belgium.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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:-
This invention relates to an electric alarm arranged in such manner that it can
call attention immediately if it be shaken in any attempt at fraudulent opening, or
burglary of any article of furniture, safe or plate-chest, on which it may be placed,
by means of one or more calls given by alarm-devices, such as bells, electric
trumpets, detonators and the like. placed at pleasure in suitable positions.
Similarly it will give a like indication if certain of the electric loads belonging to
it are broken in the act of committing a burglary, for instance.
In this way, every displacement or derangement of the apparatus in the manner
hereinafter described is promptly announced by an alarm.
I shall hereafter describe the invention, referring to the Figures 1 to 4 of the
accompanying drawing, wherein is represented a form of construction of the appar-
atus for an electrical alarm, merely by way of example, reserving the right of
altering the form of the various parts, without thereby in any way altering the
principle itself of the invention.
Fig. 1 is a diagram, showing the principle of the apparatus.
Fig. 2 represents a front elevation of the apparatus, partially in section (on the
right hand side of the view), the electrical connections being indicated by dotted
lines.
Fig. 3 is a side elevation of the apparatus whereof
Fig. 4 is a vertical cross-section.
In a closed circuit siich as A B CRDEHF, are introduced a resistance R and
an electro-magnet E. The core of the latter is capable of attracting the freely
suspended armaturo W.
As long as an electric current circulatos through the electro-magnet E, the
armaturo W is held fast in a certain position, out of the vertical. Every rupture
of the circuit must therefore have the effect of releasing the armature W, so that
it at once returns to the normal or vertical position; and completes a shunt
circuit A BJ NDEHF, out of which the resistance R is shunted which will have
the effect of setting up a current of increased intensity in the electro-magnet E and
producing a more powerful attraction on the armaturo W momentarily, the circuit
breaking between J and N the instant that this more powerful attraction becomes
effective, and so on. Thus in its movements, whether induced by shaking or by
the rupture or any other change first lessening the current in the original circuit,
(prior to increasing the current in the electro-nagnet E immediately after) this
armature is arranged to alternately make and break a local circuit, whereof the
alarm device forms part.
The apparatus comprises.―
First a lower electro-magnet E horizontally placed and secured to a spindle G³,

page_text: on which it is adjustable at pleasure by means of a fixing nut or sleeve G; the core
of this electro-magnet is provided at both ends with a noteh or rebate for the
reception of two pieces a, a², sorving as armatures, the equivalent of the armature W
of Fig. 1. The lower electro-magnet E in Figs. 2, 3, and 4 is intended to be
Recured further away from the base-plate of the apparatus than it is shown in
Figs. 3 and 4.
Secondly there is an upper electro-magnet H, whereof the core N S is suspended
between two pivots P P and may therefore be displaced by oscillation inside of
the electro-magnet H. The finely tapering ends or points of these pivots are
formed of hardened steel and screwed into two copper pins C¹ C' which, in their
turn, are screwed at uu into the iron coro N S.
These pieces C' C' serve at the same time to carry others of soft-iron a a',
forming the magnetic extremeties of the core N S, and also acting as the armatures
of the electro-magnet E, the parts a a¹ being as aforesaid the equivalent of the
part W, Fig. 1.
The counter-pivots (or pivot-holders), whereof the extremeties are also of
hardened steel are fixed to the ends of aet-screws R° R', in copper, carried by
brackets K K'.
At M is a counterpoise serving as regulator; and J' is a phosphor-bronze apiral
spring fixed, on the one hand, to the axis of the core N'S from the principal
portion of which it is insulated, and connected on the other hand, to a current-
contact 0; at C is fixed, similarly to the counterpoise M, an L-shaped piece
carrying a silver blade g, which, in its oscillating movement, corresponding to that
of the core N S, is limited in travel between two discs and (Fig. 3) on the
screw Q, enabling, when the apparatus´is regulated, the blade g to be brought to
the centre of the space left between the two disos s and s¹.
This systom of sorew and discs is sustained also by a sleeve and fixing screw
upon a horizontal pin or spindle.
to
By its action the electro-magnet H maintains the armatures a a¹ (Fig. 2) the
equivalent of W (Fig. 1) in a permanently magnetic condition i.e. of polarisation.
The circuits ABCDEHF and ABJNDEHF, and the resistance R of
Figure 1, are indicated diagrammatically in Figure 2, whence it will be seen that
any shaking of the instrument shown in Figure 2 will cause the blade
intermittingly complete the shunt circuit A BINDEHF at one or other of the
discs in parallel with the circuit ABCDEHF; also, if the portion BCR of
the leads be ruptured the magnets HE will first be de-energised and then, the
resistance R being out of circuit and the normal equilibrium between the main
current, which just balances the tendency of the armature a a¹ (or W) to swing
into the vertical being disturbed, the shunt circuit will similarly be completed, and
the alarm S inserted therein will become operative, until the circuit A. BJ NDEHF
be interrupted at J N which will occur immediately after its completion by reason
of the re-energising of the magnets HE.
The switch N' serves to interrupt the main circuit when desired, and the switch N
to interrupt the shunt.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what mauner the
same is to be performed, I declare that what I claim is.-
1. The arrangement of a horizontal electro-magnet E, its methods of fixture and
regulation.
2. The arrangement of the core of the upper electro-magnet H forming on
armature and capable of oscillating within the coil, owing to the combination of
pivots and counter-pivots h h¹.
3. The employment and the combination of a spiral J serving to take the
current and fixed upon the axis P P'.
.
4. The use and combination of the counter-poise M and of the support for the
silver-blade a

page_text: 5. The use and combination of a system of contact regulation with the aid of two
discs, and fixed upon a screw Q.
6. The use and combination of the system represented in the diagram, Fig. 1.
7. The arrangement of the connections as shown in Fig. 2.
Dated this 18th day of October 1895.
BOULT & WADE,
Agents for the Applicant.