Electric Thief and Fire Alarm.
Year: 1891

page_text: Date of Application, 4th Feb., 1891
Complete Specification Left. 5th Oct., 1891-Accepted. 30th Jan., 1892
PROVISIONAL SPECIFICATION.
Electric Thief and Fire Alarm.
I, EMANUEL BERG of Link Str. 29, Berlin W., Germany, do hereby declare
the nature of this invention to be as follows:-
The principal parts are: a suspended tube E placed on or above an iron safe or
a door such, that by means of an adjustable weight N the lower parts of the tube
rest upon a stud A, which is screwed into the door and penetrates the tube through
the hole bored for this purpose. At the lower end of the tube terminate two line-
wires 1 and 3 and one common return wire 2. Is the tube suspended 2 and 3 are
pressed together and the current thus set up, keeps the armatire of the relay V
attracted.
On increasing the weight N, 2 and 3 are bend together towards H. and for
the time of the additional current the armature of the relay W is attracted and
releases H, which on falling closes the local circuit including a bell Y. On
deminishing the weight N the contact of 2 and 3 is broken, Z is released and closes
the local current likewise as before.
The spring 2 made out of two different metalls only keeps straight at the usual
temperature of the atmosphere on increasing that it bends in such direction that
contact is made with H. and thus acts as a fire alarm.
Dated this 30th day of January 1891.
EMANUEL BERG,
COMPLETE SPECIFICATION.
Electric Thief and Fire Alarm.
I, EMANUEL BERG of Berlin, W. Link Str. 29 Germany 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 an electric thief- and fire-alarm, which is constructed in
such a way that no one even the manufacturer finds any way of preventing the
proper signalling of any burglars attempt. The principal parts of which are:
a suspended tube E placed on or above an iron safe or a door such, that by means
of an adjustable weight N the lower part of the tube E rests against a stud A,
which is screwed either into the door and penetrates the tube through the hole
bored for this purpose, or into the terminal spring of the wire 2. At the lower end
If
of the tube terminate two line-wires 1 and 3 and one common return wire 2.
the tube E is suspended 2 and 3 are pressed together and the current thus set up,
keeps the armature of the relay V attracted. On increasing the weight N, 2 and 3
are bend together towards H and for the time of the additional current the
armature of the relay W is attracted and releases X, which on falling closes the
local current likewise as before. As in the wires 2 and 3 a current is constantly
circulating, but in the wire 1 not, an electrician might be able to detect 1 from 2
and 3. To prevent this a masking, wire 0 is applied, parallel to the wire 1,
including a battery B. The current thus produced circulates in the wire 0 and 1
only and this current made equal in tension to the current circulating in the wires 2
and 3, it becomes impossible to detect 0, 1, 2, 3 one from the other and therefor
prevents the disconnection of the tube E from the alarm bell Y. The upper
of the suspended tube E turnes freely on horizontal pivots, such that the tube may
be turned in a vertical plan. The bearings of the pivots are covered by a cast-
iron case;
in the interior of which are also placed the binding-screws for the line
end

page_text: wires 1, 2 and 3. The line wires 1 and 3 pass from the binding screws through the
pivots of the tube E to the lower end of it, whereas the line wire 2 has a make and
breake contact K, which only comes into play when the tube E is suspended. This
contact also is protected by the cast iron case. As the slightest mechanical
disturbance of the tube E causes an oscillation of it, which not only allows the
springs 2 and 3 to flung from each other and thus to break the current but also
causes a contact of 2 and 3 with the screws 1 and 1, thus closing the working
current, it becomes impossible to detect the connections of the line wires, provided
the bell station Y with its relays is not accessible, and this is always the case in
praxis. If the iron safe is to be opened the tube E is put in its upright position.
K breaks the return wire 2 and puts the tube out of action, but as now the
armature of U is released it closes the bell circuit Y. To prevent this a cut-out is
connected into this circuit.
To secure an iron safe against the destruction of fire, the spring G3 is made out
of two different metals and therefor only keeps straight at the usual temperature;
on increasing that, it bends according to well known laws in such a direction that
contact is made with H 1 and thus acts as a fire alarm.
For the same purpose a contact-thermometer T is applied and connected between
the wires 1 and 2, such, that on increasing the temperature above a certain point,
the expending quicksilver makes contact with the upper platinum terminal.
The thermometer, special constructed for this purpose consists of a commen con-
tact-thermometer tested for a certain temperature. The highest point of the
quicksilver column at the critical temperature makes contact with the upper
platinum terminal, whereas the lower terminal reaches within a small distance
below the upper. Thus any broken up column will be connected in its parts by
the platinum wire, which serves as the lower terminal. To protect the sides of
the safe, the line wires 0, 1, 2 and 3 are leaded across the sides of the safe in an
irregular manner.
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 electric thief- and fire-alarm of which the principal parts are: a suspended
tube (E) with three line wires inclosed 1, 2, 3 2 being the commen return wire
for 1 and 3. The wires 2 and 3 terminate in springs, which on their part are pressed
together by a stud resting against a door and balanced in the middle of the tube
by means of an adjustable weight N. Thus keeping a circuit closed for the time
of equilibrium.
2. The closing of a working current by means of increasing a weight N attached
to a suspended tube E, which tube yields the pressure and makes contact with the
two closed springs 2 and 3.
3. The make and break of two kind of electric currents by means of deminishing
a weight N attached to a suspended tube E, in which case 2 and 3 flang from each
other and 2 alone makes contact with the tube.
4. For the purpose of masking the wires 1, 2, 3 the application of an additional
wire including a cell B parallel connected to the wire 1 as shown in the
figure.
5. The application of a platinum wire in the interior of contact thermometers,
reaching from the lower terminal to a small distant below the upper terminal, for
the purpose of connecting the broken up parts of the column of mercury.
6. The protection of the sides of an iron safe against burglars' attempts by leading
the line wires 0, 1, 2, 3 across the sides of that safe.
Dated this 30th day of September 1891.
EMANUEL BERG.