Improvements in Electric Alarm Apparatus applicable for Doors, Windows, Safes, and the like.
Year: 1893

page_text: Date of Application, 14th June, 1893-Accepted, 29th July, 1893
COMPLETE SPECIFICATION.
Improvements in Electric Alarm Apparatus applicable for Doors,
Windows, Safes, and the like.
We, FRIEDRICH SAUER of Gitschinerstrasse, Locksmith, and CARL
HENTZSCHEL, of 61 Krausenstrasse, Cabinet Maker, both in Berlin in the
Kingdom of Prussia, 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 or signalling apparatus chiefly intended
for use in connection with doors safes windows and the like for the purpose of
preventing and of immediately indicating (by means of an electric bell or other
suitable signal) any attempt to obtain an unauthorised opening of a door window
or in fact of any closed or locked article to which the apparatus can be applied.
We will describe our invention with reference to the accompanying drawings in
which
Figure 1 is a side view of the apparatus in action, that is to say with the electric
circuit closed.
Figure 2 is a similar view of the apparatus as installed ready for action, and
Figure 3 is a plan corresponding with Figure 1.
ia
The apparatus consists of a base a, preferably constructed of sheet metal bent
to a right angle, upon which there is pivoted the double armed lever A, upon
which a suitable spring 6 presses, as shewn.
A block d is also mounted upon the
base a, and carries the two contacts c c in such positions that they may be
electrically joined by the upper end g of the lever A. This lever is pivoted or
fulcrumed by the pivot f in the two opposed brackets or bearings e e¹ or in a similar
convenient manner. The lower arm g₁ of the lever A is so arranged that it is
moved by the bolt of a lock or otherwise, in the direction indicated by the arrow,
Figure 1, in the act of setting the apparatus. This motion lifts the upper part g
of the lever out of contact with c and c' and thus opens the electric circuit with
which the contacts are connected.
The block d may be provided with a ring i on its upper end for the purpose of
enabling it to be lifted from the apparatus and thus of putting it out of action.
To enable the removable block to be firmly held and accurately replaced, it may
be dovetailed as shewn by Figure 3, and be contained in an open topped dovetailed
recess, the sides of which may be formed by the brackets k k¹ fixed upon the
vertical member of the base.
The apparatus, when applied to a door, is fixed to that jamb on which the
striking plate of the lock is secured, the lower arm g¹ being let into the framing
to such an extent that it comes opposite to the bolt of the lock and in line with it
in such a position that when the bolt o (Figure 2) is shot forward, it pushes the
arm g' in the direction indicated by the arrow and lifts the arm g out of contact
with the terminals c c thus opening the circuit. In other cases, it is arranged
that the closing or locking of the article to be protected by the apparatus, shall in
a similar manner displace the upper arm g from the electric contacts. If now the
bolt o be withdrawn, or if the devices by means of which the arm g was displaced
from the contacts be removed, the spring b will press the arm 9 against the
contacts c c and close the electric circuit in which the bell or other electric signal
is included, thus producing an alarm or signal. Any opening of the door window
drawer or the like to which the apparatus is attached and even any unlocking of a
lock, will therefore be immediately indicated. The signal will continue in action
until the lock door or the like is again locked or closed.

page_text: When the apparatus is not required in use, the block d may be removed, when
the electric circuit will be opened.
The wires of the electric circuit may be connected by any suitable means to the
contacts cc' but when the removable block d is employed, they may be connected
to the sides k k¹ which in this case are insulated from each other. The contact c
is then connected with a contact plate on one side of the block, and c' with a
similar plate on the other side, these plates being also insulated from each other
and coming into electrical contact with k and ' respectively when the block is in
position.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. An electric alarm apparatus constructed arranged and operated substantially
as hereinbefore described and as illustrated by the accompanying drawings.
2. In an electric alarm apparatus, the combination with circuit terminals or
contacts, of a two armned lever C, constructed arranged and operated substantially
as hereinbefore described and as illustrated by the accompanying drawings.
Dated this 12th day of June A.D. 1893.
WILLIAM E. HEYS,
Agent for the Applicants.