improvements in Protective Devices against Burglary.
Year: 1899

page_text: Date of Application, 26th Oct., 1899
Comniate Specification Inft 04th 1 4000 Accontad
Oath o
1000
improvements in Protective Devices against Burglary.
I, AUGUST PETTERNEL, of No. 159, Ortsstrasse, Siebenhirten, District of
Mödling, Lower Austria, Manufacturer, do hereby declare the nature of this
invention to be as follows:
-
This invention relates to a device for preventing burglary capable of being
utilised for any kind of closed spaces such as apartments, money chests and the
like.
The essential feature of the invention is that the space or chamber to be
protected is at those places which are most liable to be broken into or opened―
1or instance, in the case of money chests, all round, or in the case of apartments,
at the door or the window or along the walls; covered with frames joined to
each other and provided with two separate sets of grooves containing air of
different densities, each provided with a barometer, so that whenever the rarified
or compressed air contained in the grooves is in any way acted upon, the closing
of an electric circuit, in which a burglar-alarm is inserted is effected, thus giving
a warning signal. The circuit is moreover automatically closed when the lock
is unlocked; so that if the unlocking is effected by an unauthorized person,
the alarm apparatus is thrown into operation.
The grooves may be provided upon both sides of the frames and are in the
form of two independent sets. The frame or solid portions projecting between
the grooves are in the same plane as, or flush with a smooth frame edge on the
outside of the plate. One set of grooves of the front surface are connected to
each other and communicate by channels with the corresponding grooves of the
rear surface; in like manner also the other set of grooves of the front surface
communicate with the corresponding grooves of the rear surface.
Both sides of the grooved frames are provided with cover plates suitably held
together, one side of these cover plates being provided with a thin varnish coat-
ing, cemented on to the grooved frame, so that an air tight joint between the
two non-communicating systems of channels is obtained. The varnish coating
may however be substituted by other suitable closing means or by simply insert-
ing for instance, india rubber pieces, which, if not adhesive in themselves, are
fixed to the frames by means of screws. It is also possible to provide a number
of grooved frames and their inner cover plates with one common outer cover
plate.
The outer cover plate is not provided with any opening, but the inside cover
plate is provided with say eight grooves, of which the four outer ones may com-
municate with one set of grooves of the frame, and the four inner ones with the
other set of grooves of the frame.
Each inner cover plate is also provided with a main groove divided into two
parts by suitable means. From this groove three grooves are branched off, the
irst one of which communicates with one of the four outer grooves of the inside

page_text: cover plate, and the second one with one of the four inner grooves of the inside
cover plate and with one set of grooves of the frame whilst the third groove has
no direct communication with the grooved frame.
Upon each inner cover plate moreover a barometer plate is fixed, by which
these grooves are formed into closed channels or conduits.
This barometer plate is provided with twelve grooves, the four outer ones are
located above the four outer grooves of the inside cover plate; the four inner ones
above the four inner grooves of the inside cover plate the two further grooves
above the third groove above referred to, and two further outer grooves above
the main groove of the cover plate.
The two last grooves are each closed or opened by a small valve which allows
the passage of air out of or into the conduits of the grooved plate, or out of or
into the arm of a barometer.
The barometer which consists of two short glass tubes containing mercury
and having their lower ends connected by a metal tube, is located in a corre-
sponding recess of the plate, which latter is moreover furnished with two grooves
one of which connects the four outer grooves of the barometer plate with one of
the two further grooves arranged above the third groove of the inner cover plate
and the other the four inner grooves of the armature plate with the second of
the two further grooves arranged above the third groove of the inner cover plate.
Upon the barometer plate is also a glass plate by which two systems of conduits
are formed, one of which connects one set of grooves of the frame with one
arm of the barometer, and the other the other set of grooves of the frame with
the other arm of the barometer.
Now in both systems of conduits, as has already been mentioned, an air pres-
sure is produced different relatively to each other and to the outer air, by either
pumping air into or out through the valves so that the mercury stands at unequal
levels in the arms of the barometer.
In the case when the device is applied to ceilings and walls the barometers are
normally suspended but where they are applied to floors they are arranged
standing.
In case of safes or chests, for instance, the inner cover plates are provided with
a number of bolts screw threaded to receive nuts passed through corresponding
openings of the frame and through the outer cover if desired the compound plate
so formed being used instead of the ordinary safe or chest walls.
The same method may be adopted for making the walls of apartments burglar
proof.
In cases where the cover plates are made of cement or a similar material, the
fastening bolts are preferably passed through the grooved frame until one half
of the outer cover plate is reached.
In all cases the frames and plates present outwardly a perfectly smooth sur-
face, offering no point of application whatever for burglars tools, and upon
damaging such plates and frames to any appreciable extent, either a communica-
tion is established between the two sets of grooves in the frame, or between one
of them and the outer air, the effect being that in the former case the mercury
levels in the barometer are equalised while in the latter case, owing to the
entering of outer air into or owing to the escaping of compressed air out of one
of the systems of conduits, the levels are displaced relatively to each other, thus
closing in either case, by means of the respective conductors, a circuit, by which
any suitable alarm apparatus may be actuated. The conducting connection
between the source of electricity and the frames and plates is made as follows:-
One pole of a battery is connected with one of the plates (in the present case
with the base plate of a regulating apparatus, arranged in the safe or chest)
whilst the other pole is connected with an insulated hollow metal projection on
one of the plates or frames. This projection is connected with an insulated
conducting wire placed in the main groove of the cover plate and connected with
apart fitting into the hollow projection above referred to.

page_text: The metal tube of each barometer is also connected with the frame by a wire,
whilst into both arms of the barometer, rods extend so as to be equidistant from
each mercury level. These are electrically connected with the conducting wire
in the main groove.
The open parts of the main groove are finally closed by means of glass plates.
Now as soon as either by boring the cover plates or in any other manner-
a connection is established between the two sets of grooves in the frame, or the
outer air enters one of the latter, the mercury of the barometers will close the
circuit, so that if an alarm apparatus is connected thereto, the signal given by
the latter will draw attention to the intended burglary.
The alarm apparatus may be of any suitable kind; in the present example a
gas generator is located in the interior of the safe and having a pipe connected
to it, fitted with a signal whistle.
The generator consists of a strong bottle shaped vessel containing bicarbonate
of sodium, or other suitable substance or liquid, and in the neck of which a
receptacle containing sulphuric acid or other suitable substance or liquid is
inserted, the latter being fitted with a discharge pipe reaching nearly down to
the bottom of the receptacle and being then turned upwards, and the top of the
said receptacle being provided with an opening covered by a layer of wax.
Through the neck of the vessel passes a hollow spring actuated bolt adapted
to be moved downward by a pawl and ratchet gear mechanism inserted in the
circuit, and during such down movement the bolt traverses the wax layer it being
moved up again under the spring action, thus the wax seal is broken and conse-
quently the sulphuric acid will be discharged from the tube and carbonic acid
will be generated with the effect of closing a valve which has been previously
pushed aside by the rod. Such gas passes through the pipe to the signalling
whistle, and causes the latter to sound. In order to obtain a suitable high pres-
sure in said pipe, a membrane arranged so as to break, when exposed to a given
pressure, may be arranged in the tube.
The pipe is made of steel and is surrounded by thin tubes of a smaller diameter,
which serve for the same purpose as the grooves in the frames and are connected
with the barometer; thus any attempted injury to the pipe between the gas
generator and the signal-whistle is instantly indicated.
In order that not only such burglaries may be indicated which are attempted
by outwardly damaging the walls but to also announce the fact of the lock
being opened, the door is provided with a contact plate having one side provided
with two contacts inserted in the circuit of the battery while in the interior of
the lock or bolt an insulated conducting pendulum is suspended.
When the door is in a closed position, the pendulum does not touch the con-
tacts, but when the door is opened, or the bolt slid back, the pendulum comes in
contact with the contacts whereby the circuit in which the alarm apparatus is
inserted, is closed, thus the opening of the door by an unauthorized person is
indicated by the signal.
In order not to actuate the alarm apparatus in case the lock is opened by
authorized persons, a setting device placed in the interior of the chamber or
space to be protected, is provided.
This device is furnished with two toothed wheels each having a notch and
capable of being adjusted, prior to locking the safe or chamber, to any desired
figure, in an analogous manner to puzzle-locks, the notches having to be brought
into line and otherwise acting in a well known manner.
Prior to each operation of unlocking being effected by an authorized person
the figure discs or wheels are moved back to their proper position by operatin
the respective number of times a key of a commutator so that a circuit, formed
by a battery, commutator, coil and key. is closed, whereby the armature of the
coil rotates one of the toothed wheels the required number of times and moves
its notch upward, while by reversing the commutator and depressing the key a
circuit, formed by the battery, commutator, coil and key, is closed, so that the

page_text: other figure disc or wheel is turned back and its notch brought into the upper
position.
If now the protected chamber is opened, a fresh circuit formed by a further
battery, a coil and two contacts is closed, so that an armature which was serving
as a support for a pair of angular arms is attracted, causing the latter to move
downward and to be followed in this movement by an open frame, which rests
on one of the arms, as far as projections of said frame, engaging with the notches
of the figure wheels will admit.
The angular arm will continue moving downwards, until one of them lies on
the open frame, in which position the coil of the alarm apparatus is disconnected,
so that no signal is given.
If the figure discs or wheels are displaced, so that their notches do not occupy
the desired position, then, in case of the circuit being closed in the same way
as before if the door be opened or the plates and frames be fractured, the arma-
ture of this last circuit is likewise attracted, but as the projections of the open
frame are prevented from engaging with the notches of the wheels, the frame
will allow the angular arms to move down freelv. during which operation a
small metal plate of one of the arms connects two contacts and closes the circuit
formed by the first battery, so that a coil attracts an armature which operates
through suitable mechanism the spring actuated bolt of the bottle which pene-
trates the wax seal, so that the carbonic acid, thus generated, causes the signal
whistle to sound.
In order that the adjustment of the figure discs can only be effected when
the arms controlling them are turned upward, that is to say, are placed in opera-
tive position, one arm is provided with two electrically connected contact pins
in the circuit of two coils, which contact pins only close the circuit, when the
arm occupies its uer position, by touching a pair of contacts in the circuit
which are insulated from each other.
PHILIP M. JUSTICE,
Chartered Patent Agent, London,
For the Applicant.
provements in Protective Devices against Burglary.
I, AUGUST PETTERNEL, of No. 159, Ortsstrasse, Siebenhirten, District of
Mödling, Lower Austria, Manufacturer, 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 a device for preventing burglary which is capable
of being utilised for any kind of closed spaces such as apartments, money chests
and the like.
The essential feature of the invention is that the space or chamber to be pro-
tected at those places which are most liable to be broken into or opened-for
instance, in the case of money chests, all round, or in the case of apartments, at
the door or the window or along the walls-is covered with plates or frames
joined to each other and provided with two separate grooved sets or frames con-
taining air of different densities; both said plates or frames being so mounted,
and each carrying inside a barometer, so that whenever the grooves or the
rarified or compressed air contained therein are in any way acted upon, the clos-

page_text: ing of an electric circuit, in which a burglar-alarm is inserted is effected, thus
giving a warning signal. The circuit is moreover automatically closed when
the lock is unlocked; so that if the unlocking is effected by an unauthorized
person, the alarm apparatus is thrown into operation.
The invention is shown in the accompanying drawing in which :-
Figs. 1, 3 and 2 represent a portion of one of the grooved frames or plates in
front and rear elevation and cross section respectively, these figures showing
how the grooves are provided unon both sides of the frames, and form two
entirely independent sets 1, 2. The grooves are about 1 millimetre in width;
the distance between the individual grooves is likewise 1 millimetre and the
frame or solid portions projecting between the grooves are in the same plane as,
or flush with, the smooth frame edge 3. The grooves 1 of the front surface
are connected to each other and communicate by cross channels 4 of the frame
with the grooves 1 of the rear surface; in like manner also the grooves 2 are
connected with each other and communicate by cross channels 5 with the grooves 2
of the rear surface.
Both sides of the grooved frames are provided with cover plates 6. 7 (Figs. 4.
5 and 6) held together by screws, one side of these cover plates being provided
with a thin varnish coating, this varnished side being cemented on to the grooved
frame, so that a perfect hermetical joint between two non-communicating
systems of channels is obtained. The varnish coating between the grooved
frames and the cover plates may however be substituted by other suitable tichten-
ing means or by simply inserting-for instance, india rubber pieces, which, if
not adhesive in themselves, are fixed to the plates by means of screws. It is
also practicable to provide a number of grooved frames and their appertaining
inner cover plates with one common outer cover plate.
In all cases the outer cover plate 6 that is to say the one most directly ex-
nosed to being forced or broken, is not provided with any opening, whereas each
inner cover plate 7 is provided with eight grooves, of which the four outer ones S
communicate with the set of grooves 1, and the four inner ones 9 with the set
of grooves 2.
Moreover each inner cover plate is traversed by a main groove 10 divided trans-
versely into two parts by an inserted packing 34. From this groove three
grooves 11, 12 and 13 are branched off, the first one of which 11 communicates
with one of the grooves 8, and the second one 12, with one of the grooves 9
and with the set of grooves 1 or 2 respectively, whilst the third groove 13 has
no direct communication with the grooved frame.
The object of these grooves will be described further on.
Upon each inner cover plate moreover a plate 14 is fixed, by which the grooves
arranged in the cover plate are formed into closed channels or conduits.
The plate itself is provided with twelve grooves, the four outer ones 15 see
Figs. 7 and 8 are located above the grooves 8; the four inner ones 16 above the
grooves 9: the two grooves 17 and 18 above the groove 13; and the two outer
grooves 19 and 20 above the main groove 10 of the cover plate.
The two grooves 19 and 20 are each closed or opened by a small set screw 21
peting as a valve which allows the passage of air out of or into the conduits of
the grooved plate, or out of or into the arm of the barometer 22.
The barometer 22 which consists of two short glass tubes containing mer-
cury and having their lower ends connected by a metal tube, is located in a
corresponding recess of the plate 14, which latter is moreover furnished with
Grooves 23 and 24, the former of which connects the grooves 15 and 17 and the
latter the grooves 16 and 18 with one another. Upon the plate 14 is also a
glass plate 25 Figs. 4 and 8 by which two systems of conduits are formed. ene
of which connects the grooves 1 with the one arm of the barometer, and the other
the grooves 2 with the other arm of the barometer.
Now in both systems of conduits, as has already been mentioned, an air
pressure is produced different relatively to each other and to the outer air, by

page_text: either pumping air into or out through the valves 21, so that the mercury
stands at unequal levels in the arms of the barometer.
In the case when the device is applied to ceilings and walls the barometers
are normally suspended as shewn in Fig. 7 but where they are applied to floor-
ings, they are arranged standing; and for the latter purpose they are constructed
as shown in Fig. 16.
The space to be protected is fitted with the above described grooved frames
furnished with cover plates, plates 14 and barometers, the construction of the
frames and plates being adapted to the special requirements of each case.
In case of safes or chests, for instance, the inner cover plates are provided
with a number of screw threaded pins 26 (Figs. 4. 5 and 6) passed through corre
sponding openings of the iron frame, used in substitution for the ordinary saf
or chest walls, and tightened by means of nuts.
The same method may be adopted for making the walls of apartments burglar
proof.
In cases where the cover plates are made of cement or a similar material, the
fastening pins 26 Fig. 6 are preferably passed through the grooved frame into
the outer cover plate.
In all cases the frames and plates arranged beside and above one another.
present outwardly a perfectly smooth surface, offering no point of application
whatever for burglars tools, and upon damaging such plates and frames to any
appreciable extent, either a communication is established between the grooves 1
and 2 or between one of them and the outer air, the effect being that in the
former case the mercury levels in the barometer, are equalised while in the latter
case, owing to the entering of outer air into or owing to the escaping of com-
pressed air out of one of the systems of conduits, the levels are displaced rela-
tively to each other, thus closing in either case, by means of respective con-
ductors, a circuit, by which any suitable alarm apparatus may be actuated. The
conducting connection between the source of electricity and the frames and
plates is made as follows:-
One pole of the battery 28 (Fig. 10) is connected with one of the plates (in
the present case with the base plate 73 of the regulating apparatus. Fig. 10,
arranged in the safe or chest, Fig. 9), whilst the other pole is connected with an
insulated hollow metal projection 29, Figs. 5 and 9 of one of the plates or frames.
This projection 29 is connected with an insulated conducting wire 30 Fig. 5, 9.
17. 18, 19 placed in the main groove 10 of the cover plate 7 and being connected
with a tongue 31, fitting into the hollow projection 29 of the subsequent plate.
Different forms of these are shewn in Figs. 17, 18 and 19.
The parts 29, 31 and the wires 30 of all plates thus are electrically connected
with the one pole of the battery, whilst the other pole. as already mentioned. is
directly connected with the base plate 73 Fig. 10. With the latter the metal
tube of each barometer 22 is also connected by a wire 32, whilst into both arms of
the barometer, wires 33 extend so as to be equi-distant from each mercury level.
These are passed through the grooves 17 and 18, connected with the groove 13
and electrically connected with the wire 30.
The open parts of the groove 10 divided by the packing 34 are finally her-
metically closed by means of glass plates.
Now as soon as either by boring the cover plates or in any other manner-
a connection is established between the two systems of grooves 1, 2, or the outer
air enters one of the latter, the mercury of the barometers 22 will close the
circuit, so that if an alarm apparatus, is connected thereto, the signal given by
the latter will draw attention to the intended burglary.
The alarm apparatus may be of any suitable kind; in the present example a
gas generator 35 is provided, located in the interior of the safe and having a
pipe 36 connected to it, fitted with a signal whistle.
The gas generator consists of a strong wrought iron bottle shaped vessel 37
Fig. 12 containing bicarbonate of sodium, or other suitable substance or liquid,

page_text: and in the neck of which a receptacle 38 containing sulphuric acid or other
suitable substance or liquid is inserted, the latter being fitted with a discharge
pipe 39 reaching nearly down to the bottom of the receptacle 37 and being then
turned upwards, and the top of the said receptacle 38 being provided with an
opening covered by a layer of wax 40.
Through the neck of the vessel passes a bolt 41 which is held up by a pin 41*
on a wheel 41 engaging its head. The wheel 41b forms part of a train in which
is a ratchet wheel 41° held from moving by a pawl of an armature 68. The
bolt 41 has pressure exerted upon it by an arm 41d which bears on a pin of the
bolt and is drawn down by a spring 41° so that when the armature is attracted
to the magnet (4 the bolt is thus forced down against the pressure of a spring 41
surrounding it until it passes into and breaks a brittle wax seal 40 of the recep-
tacle 38. This operation allows the sulphuric acid to be discharged from the
tube 39 upon the bicarbonate so that carbonic acid gas is generated. After
breaking the seal the arm 41d passes the pin on the bolt thus relieving the
pressure on same and the spring 41 will return the bolt, the gas pressure closing
the flap valve 42 which has been previously pushed aside by the bolt so that the
gas cannot escape around such bolt. The gas generated passes through the
tube 36 to the signalling whistle and causes the latter to sound. In order to
obtain a sufficiently high pressure in the tube 36 a membrane arranged so as to
break when exposed to a given pressure may be arranged in the tube. The
tube 36 is made of steel and is surrounded circularly by thin tubes 43 Figs. 13,
14, 15 of a smaller diameter, which serve for the same purpose as the grooved
frames and are connected with one of the barometer tubes in the manner repre-
sented in Fig. 15; thus any injury to the conduit between the gas generator
and the signal-whistle is instantly indicated so that any attempt to disconnect
the signal whistle by cutting the pipe 36 is made ineffective.
In order that, especially in the case of safes or chests not only such burglaries
may be indicated which are attempted by outwardly damaging the walls, but to
also announce the fact of the lock being opened, the lock is constructed in the
manner indicated in Fig. 11, and an adjusting device such as represented in
Fig. 10 is arranged in the interior of the safe or chamber to be protected.
The lock does not in general differ from an ordinary lock except that in the
door a fixed prism 46 is arranged having one side provided with two contacts 44,
45 inserted in the circuit of the battery 28, while in the interior of the lock bolt 47
an insulated conducting pendulum 48 is suspended.
When the door is in a closed position, as indicated in Fig. 11, the pendulum
does not touch the contacts 44 and 45; but when the door is opened, or the bolt
slid back, the pendulum 48 comes in contact with the contacts 44 and 45, whereby
the circuit in which the alarm apparatus is inserted, is closed, thus the opening of
the door by an unauthorized person is indicated by the signal.
In order not to actuate the alarm apparatus in case the lock is opened by
authorized persons, a setting device Fig. 10, placed in the interior of the chamber
or space to be protected, is provided.
This device is furnished with two toothed wheels 49 and 50 each having a
notch 51 and capable of being adjusted, prior to locking the safe or chamber, to
any desired figure, in an analogous manner to puzzle-locks, the notches 51 having
to be brought into line and otherwise acting in a well known manner.
Prior to each operation of unlocking being effected by an authorized person
the figure discs or wheels are moved back to their proper position by operating
the respective number of times a key 52 of the commutator 53, so that a circuit,
formed by the battery 54, commutator 53, coil 56, key 52, battery 54, is closed.
so that the armature of the coil 56 rotates the toothed wheel 49 the required
number of times and moves the notch 51 upward, while by reversing the com-
mutator 53 and depressing the key 52 a circuit, formed by the battery 54,
commutator 53, coil 57, key 52, battery 54, is closed, so that the figure disc or
wheel 50 is turned back and its notch 51 brought, into the upper position.

page_text: If now the protected chamber is opened, the circuit formed by the battery 28,
coil 58, contacts 44 45 and battery 28, is closed, so that the arma-
ture 59, which was serving as a support for the angular arın 60,
61, is attracted; the latter moves downward and is followed in this move-
ment by the frame 62, resting on the arm 60, as far as the projections 63
of the said frame 62, engaging with the notches 51, will admit.
The angular arm 60, 61, now will continue moving downwards, until the
portion 61 lies on the frame 62; in which position the coil 64 of the alarm
apparatus is disconnected, so that no signal is given.
If the figure discs or wheels 49 and 50 are displaced, so that their notches 5.1
do not occupy the upper position, then, in case of the circuit of the battery 28
being closed in the same way as before if the door be opened or the plates and
frames be fractured, the armature 59 is likewise attracted, but as the projec-
tions 63 of the frame 62 are prevented from engaging with the notches 51, the
frame will allow the angular arm 60, 61, to move down freely, during which
operation the small metal plate 65 of the arm 60 connects the contacts 66 and 67
and closes the circuit formed by the battery 54, contacts 66 65 67, coil 64, base
plate 73 and battery 54 so that the coil 64 attracts the armature 68.
In this movement the bolt 41 penetrates the wax seal 40, so that sulphuric
acid is discharged, and the carbonic acid, thus generated, causes the signal whistle
to sound.
In order that the adjustment of the figure discs 49 and 50 can only be effected
when the arms 60 and 61 are turned upward, that is to say, are placed in operative
position, the arm 61 is provided with two electrically connected contact pins 69
and 70 in the circuit of the coils 56 and 57, which contact pins only close the
circuit, when the arm 61 occupies its upper position, by applying themselves.
against the contacts 71 and 72, which are insulated from each other.
Thus any attempted burglary will in any case be indicated in a reliable
manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
-
1. A protective device against burglary, comprising plates or frames for cover-
ing the space to be protected, provided with two sets of grooves containing air
of a different density to each other and also to the outer air each being con-
nected to an arm of a barometer, the mercury level of which when the grooves
are broken into will close a circuit in which is an alarm apparatus substantially
as described.
2. In a device of the kind described in the preceding claim, a barometer the
mercury in which is connected with one pole of a source of electricity,-the
other pole of which is connected with two contact wires, terminating in the
barometer arms above the mercury levels, substantially as and for the purpose
described.
3. In a device of the kind described in the first claim, a central frame having
both sides provided with grooves and having two cover plates tightly applied
against said frame, the inner cover plate receiving a barometer, substantially
as and for the purpose described.
4. In a device of the kind described in the first claim, an alarm apparatus
consisting of a vessel containing a gas developing substance or liquid situated in
the space to be protected and connected with a signal device and containing
a receptacle filled with a substance or liquid which will develop gas from the
substance or liquid in the vessel, a spring actuated bolt being arranged near
the receptacle, the arrangement being such that when the armature of an electro
magnet is attracted said bolt is released and forced down and causes the two
substances or liquids to come into contact with each other so that a gas is
generated which causes the signal to be operated, substantially as described.

page_text: 5. A device of the kind described in the first and fourth claims in which a
tube leading from the gas generator to the signal device is surrounded by small
tubes communicating with the sets of grooves in the plates or frames so that a
signal may be given on any attempt to cut the gas tube.
6. A device of the kind described in the first claim, in a circuit of which,
actuating the alarm apparatus are two contacts in the door of the chamber to
be protected, which are electrically connected by a pendulum suspended from
the lock bolt, when the door lock is opened, substantially as and for the purpose
described.
7. A device of the kind described in the first and sixth claims, in which, for
the purpose of actuating the alarm apparatus only in case the opening of the
lock is effected by an unauthorized person, a circuit containing a coil of the
alarm apparatus is provided with contacts, which are closed by the conducting
plates of an angular arm as soon as a support forming the armature of an
electro magnet included in the circuit of the contacts is attracted, a frame
adjusted beforehand enabling the angular arm to freely descend, substantially
as described.
S. A device of the kind described in the first and seventh claims, in which a
frame. is provided with projections, which are adapted to drop into notches of
toothed wheels as soon as the latter have their notches placed upwards by an
authorized person, the object being to place the frame in such a position that,
when the lock is opened by an authorized person, said frame will prevent the
angular arm from descending and consequently from connecting the contacts, sub-
stantially as described.
9. A device of the kind described in the first, seventh, and eighth claims, in
which the circuit, effecting the adjustment of the toothed wheels by means of
pawls or levers, can only be closed by contact pins, when the angular arm
occupies its operative position, the object being to only admit of an adjust-
ment of the toothed wheels, when the angular arm has been previously placed
in its upper position, substantially as described.
Dated this 24th day of July 1900.
PHILIP M. JUSTICE,
Chartered Patent Agent, London,
For the Applicant.