Improvements in Contacts for Making and Breaking Electrical Circuits.
Year: 1893

page_text: Date of Application, 16th May, 1893
Complete Specification Left, 24th Jan., 1894-Accepted, 24th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Contacts for Making and Breaking Electrical
Circuits.
We, SIEMENS BROTHERS & Co. LIMITED, and FRANK JACOB, of 12 Queen
Anne's Gate, Westminster, in the County of Middlesex, Electrical Engineers, do
hereby declare the nature of this invention to be as follows :-
Our invention relates to contacts for making and breaking electrical circuits for
lights, bells or other signals, such contacts being especially adapted for being
operated by the opening or closing of a door or window, as for instance in the case.
of a burglar alarm. The chief object which we have in view is to arrange all the
contact appliance in a position where it is invisible and not readily accessible, and
protected from dust and damp.
We shall describe a contact according to our invention arranged to operate as a
burglar alarm when a door is opened. We fix concealed in the wood of the door
near to its edge, a magnet, and in the jamb or frame, so as to be near this magnet,
an iron contact lever which, when the door is closed, is attracted by the magnet
near it in opposition to a weight or spring; but, when the door is opened and the
magnet is thus withdrawn, the lever is moved by the weight or spring so as to make
or break an electrical contact connected by concealed insulated wires to a suitable
battery, and to a bell or other signal. The magnet may be fixed in the jamb, the
contact lever being placed in the door, and in that case the conductors to and from
the contact are arranged to turn on joints so as to maintain the circuit notwith-
standing the movement of the door on its hinges. In like manner the contacts may
be arranged to give an alarm on the movement of a window. Instead of applying
the contacts for purposes of alarm, they might obviously be applied to make or
break circuits for electric lights or other purposes.
Dated this 16th day of May 1893.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION..
Improvements in Contacts for Making and Breaking Electrical
Circuits.
We, SIEMENS BROTHERS & Co. LIMITED, and FRANK JACOB, of 12 Queen
Anne's Gate, Westminster, in the County of Middlesex, Electrical Engineers, 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 :-
Our invention relates to contacts for making and breaking electrical circuits for
lights, bells or other signals, such contacts being especially adapted for being
operated by the opening or closing of a door or window, as for instance in the case
of a burglar alarm.
The chief object which we have in view is to arrange all the contact appliance
in a position where it is invisible and not readily accessible, and protected from
dust and damp.
We shall describe a contact according to our invention arranged to operate as a
burglar alarm when a door is opened. As shewn in Fig. 1 of the accompanying

page_text: drawings we fix concealed in the wood of the door D near to its edge, a magnet M,
and in the jamb or frame J so as to be near this magnet, an iron contact lever L
which, when the door is closed, is attracted by the magnet M near it in opposition
to a weight, or it might be a spring on the other arm of the lever. When the door
is opened and the magnet is thus withdrawn, the lever L is moved by the weight or
spring so as to break an electrical contact C connected by concealed insulated
wires W to a suitable battery and to a bell or other signal.
The lever L might obviously be arranged so as to break contact when the door
is closed and to make contact when it is opened. Fig. 2 shews a horse shoe
magnet M and a contact lever L' arranged vertically. As shewn in Fig. 3 the
magnet M² may be fixed in the jamb J the contact lever L being placed in the
door, and in that case the conductors to and from the contact C are arranged at or
near the door hinges to turn on joints, or with flexible parts, so as to maintain the
circuit notwithstanding the movement of the door on its hinges. Instead of a
permanent magnet, an electromagnet may be employed as shewn in Fig. 3. The
lever I may be a magnet moved so as to make or break contact when a piece of
iron in the door is near it, and this piece of iron may be the bolt of the lock
causing the lever in the jamb to make or break contact when the bolt is shot or
withdrawn. Contacts may obviously be arranged in a manner similar to the door
contacts to give an alarm on the movement of a window. Instead of applying the
contacts for purposes of alarm, they might obviously be applied to make or break
circuits for electric lights or other purposes.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
An electric contact consisting of two magnetic parts the one moveable as in a
door or window, the other stationary as in a door jamb or window frame, so arranged
that the one is moved so as to make or break contact for an electric circuit when
the other is near it, substantially as described.
Dated this 24th day of January 1894.
ABEL & IMRAY,
Agents for the Applicants.