Improvements in or connected with Electric Burglar and other Alarms.
Year: 1896

page_text: Date of Application, 5th May, 1896
Complete Specification Left, 5th Feb., 1897-Accepted, 3rd Apr., 1897
PROVISIONAL SPECIFICATION.
Improvements in or connected with Electric Burglar and other
Alarms.
I, THOMAS ALFRED CLARKE of 203 Derby Road, Bootle in the County of
Lancaster, Licensed Victualler, do hereby declare the nature of this invention to
be as follows:-
This invention has for its object an electric alarm, applicable inter alia as a
burglar alarm which shall also keep the burglars outside the door sufficiently long
to enable the person alarmed to be put on the defensive, also as an alarm for
rousing servants in the morning etcetera.
As applied for use as a burglar alarm, it consists in an electric bell or other
alarm worked electrically, a battery to supply that bell, and a pair of insulated
wires leading to the actual safety appliance. This consists of a wedge formed of
wood or other material in two pieces separated by a steel or other spring.
These pieces at the point are preferably united by a hinge and are provided on
the outside with metal contact plates which project slightly at each edge, to which
by means of a contact screw of any convenient description, or other contact devices,
the two wires are respectively connected. The lower half of the wedge is supplied
with two or more metal pins projecting therefrom having sharp points, or in some
cases may be shod with rubber to prevent slipping on a concrete floor. The alarm
is provided with means such as a pivoted lever which falls when the bell begins
ringing and makes contact in a local circuit, whereby immediately the contact is
made the bell continues ringing until the local circuit is broken by the occupant of
the house.
The mode of action is as follows-
The wedge is pressed against the floor until the two points enter the same, and
these hold it rigid, it being placed in such a position that the point of the wedge is
just under the bottom of the door. The door can thus be opened to any desired
extent, or actually closed. If the door be forcibly opened wider it passes over the
hinge, depressing these two halves until their thick ends touch, the contact is made
and the bell or other alarm device rings loudly. If the burglar attempts by means
of a knife or other instrument to push the wedge shaped piece away, he will, owing
to the peculiar arrangement of the contact strips, cause contact to be made in
whatever way he inserts the instrument. In case he should insert a piece of wood
or other instrument, not a knife or the like, contact springs are provided at the
ides of the two halves of the hinge so that a very light pressure will cause contact
so be made. If he endeavours to cut the wires, the slightest movement of the wires
vill cause a contact, by pulling the wedge shaped terminals together.
It is obvious that the wires can be brought to any desired point and ring the
ell there, or that two bells can be on the circuit, one rung so as to alarm the
urglar, the other to alarm the watchman at a distance, also that the circuit formed
an manipulate any other electrical device useful for circumventing the burglar.
The spring for keeping the two plates apart is preferably a simple bent blade or
everal blades attached to one of the halves of the wedge near one end, arched
ver, and then returning again to near the same wedge near the other point, and
unded at the end to prevent it cutting into the wood. The battery is preferably
dry battery and the bell with a coil etcetera placed inside so as to occupy as little
om as possible.

page_text: As applied to other alarms besides burglar alarms the invention will be obvious
without further description. Means may be provided for using the apparatus
either as a burglar alarm, or as an invalid's call bell, a device being used for
changing the continuous ringing of the bell as in the case of an alarm, to a call
which rings so long as the button is being depressed.
Dated this 4th day of May 1896.
WM. P. THOMPSON & Co., .
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
Improvements in or connected with Electric Burglar and other
Alarms.
I, THOMAS ALFRED CLARKE of 203 Derby Road, Bootle in the County of
Lancaster, Licensed Victualler, 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 has for its object an electric alarm, applicable inter alia as a
burglar alarm which shall also keep the burglars outside the door sufficiently long
to enable the person alarmed to be put on the defensive, also as an alarm for rousing
servants in the morning etcetera.
As applied for use as a burglar alarm, it consists in an electric bell or other
alarm worked electrically, a battery to supply that bell, and a pair of insulated
wires leading to the actual safety appliance.
Referring to the accompanying drawing-
Figure 1 shows the safety appliance underneath the door of a room and the
wires leading to a battery and bell which may be enclosed in a box for
convenience.
Figure 2 is an enlarged view of the safety appliance with parts broken away for
clearness.
Figure 3 a side elevation of the same showing how contact is made and
Figure 4 a plan thereof in its open or normal position.
In these A is the safety appliance consisting of a wedge formed of wood or other
material in two pieces B B. These pieces may be connected at their converging
points by a hinge and their opposite ends kept apart by a spring, but I have found
that the metal contact pieces to be hereinafter described serve the purpose, I have
therefore dispensed with them. CC are two metal contact plates to which the
wires D D' leading to the battery are respectively connected. The metal contact
strips before referred to and shown best in Figure 2 are secured to the two
pieces B B¹ forming the wedge in any suitable manner and extend both along the
top of the uppermost half B of the wedge and underneath the lower half B and
are turned over the ends of the widest part of the wedge. It will be seen that the
outside strip E touches the top contact plate C but stops short of the bottom
plate C', while the next one E' stops short of the top plate but is connected to the
bottom plate and so on with each alternate strip. F F are side contact plates
arranged one on each side to the upper and lower half respectively and adapted to
make contact with strips G only one of which can be seen in the drawing. H are
spikes projecting from the lower half of the wedge for fixing the appliance to the
floor as shown in Figure 3, or in the case of a concrete floor where the spikes
cannot be used the appliance may be shod with rubber I having a serrated surface
(shown only in Figure 2) to prevent slipping.
The mode of action is as follows:-
The wedge is pressed against the floor until the spike or spikes H enter the same

page_text: as shown in Figure 3 and in such a position that the thin end of the wedge is just
under the bottom of the door when such is closed, see Figure 1, or if desired it could
be placed so that the door could be opened to any desired extent before engaging
the wedge. If the door be forcibly opened it depresses the upper half B of the
wedge until the plates C C¹ come together, thereby making contact and completing
the circuit. This causes the bell or other alarm device to ring loudly. If an
attempt be made to force the door still further open the appliance acts as a wedge
to prevent such opening or if the burglar or other person attempts by means of a
knife or other instrument to push the wedge away before opening the door he will,
owing to the peculiar arrangement of contact springs cause contact to be made in
whatever way he inserts the instrument, for instance if a knife or other conductor
touches any two strips marked E E¹, contact will be made as will be clearly understood
from the drawing, if either of the two side strips be lightly pressed contact will be
made, as in this case one of the strips touches the outside top strip of the upper
half of the wedge at the point e (Fig. 4) and the other a similar strip on the lower
half of the wedge on the opposite side. When these are pressed inwards they
touch the strips G which strips (as clearly shown in Figure 2) are in contact with
the plates C C¹. If the burglar endeavours to cut the wires a slight movement of
the same will cause a contact by pulling the terminals C C₁ together.
It is obvious that the wires can be brought to any desired point and ring the bell
there, or that two bells can be on the circuit, one rung so as to alarm the burglar,
the other to alarm the watchmen at a distance, also that the circuit formed can
manipulate any other electrical device useful for circumventing the burglar.
The battery is preferably a dry battery placed in a box with the bell and a
coil etcetera so as to occupy as little room as possible.
As applied to other alarms besides burglar alarms, the invention will be obvious
without further description. Means may be provided for using the apparatus
either as a burglar alarm, or as an invalid's call bell, a device being used for
changing the continuous ringing of the bell as in the case of an alarm, to a call
which rings so long as the button is being depressed.
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. In a burglar alarm wedge, the combination of the two portions forming the
upper and lower parts of the wedge with a series of thin contact plates forming
the hinge and electrically connected with contacts of opposite polarity side by side
or one over the other and covering a greater portion of the surface of the wedge,
whereby if a metal tool be used to push it away it will complete the circuit by
bridging the distance between two contacts or by pressing them against each
other substantially as described.
2. The combination with an electrical alarm wedge, formed of two parts meeting
at the point and even when closed forming a wedge capable of holding the door, of
a holding device at the bottom capable of holding into the floor or forming a
strong, mechanical resistance therewith, whereby even after the two portions of the
wedge have been pressed together it shall still act as a stout resistance to prevent
the opening of the door.
3. The combination of the wedge A having conducting strip G fixed thereto
with the wedge B having spring blade F¹ of opposite polarity to the strip G, and
a battery X having wires D1 and D in electrical connection respectively with the
blade For F¹ and the strip G and having a bell or alarm on the circuit.
DL:
- 1007
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.