US2249560A - Radio alarm system - Google Patents

Description

July 15, 1941. J. o; HOWTON 2,249,560

RADIO ALARM SYSTEM I Filed Feb. 21, 1938 JW 0. 370101374X.

Patented July 15, 1941 I arrests RADIO ALARM SYSTEM James 0. Howton, Freewater, Oregz, assignor to Howton Radio Alarm Company, Seattle, Wash.

Application February 21, 1938, Serial No. 191,788

6 Claims.

The invention herein disclosed relates to an alarm system and more particularly an alarm transmitting system wherein the alarm is transmitted by radio.

It is an object of this invention to provide a circuit that will cause the radio transmitter to operate appropriately whenever a protective circuit wired about the premises is disturbed.

A further object is to provide an alarm system that will send burglar and/or fire alarms, the arrangement being such that when both the fire and burglar alarm circuits are disturbed, there will be no interference between themessages broadcast over the single transmitter which is common to both alarms.

The drawing shows diagrammatically the preferred electrical hook-up of .the radio transmitter and the circuit used to control its operation.

The transmitter, as here shown, has a piezocrystal ID to control the radio frequency. The controlled radio frequency is imposed upon the grid of a tube II, to the plate circuit of which is connected an inductance l2. Th inductance has a variable condenser l3 connected across its terminals and a test jack l4 connected in line with a choke coil l5 which is in series between one terminal of the inductance and the positive terminal of a motor generator set It. The test jack is provided in order that a meter may be temporarily connected into thecircuit for tuning purposes.

In order to amplify the output of this first circuit, the output of the inductance is connected to the grid of a tube l1 through a capacitance Ill. The plate of tube I! is connected to an inductance l9 which has a variable condenser across its terminals. The motor generator supplies suitable excitation to the plate of tube I! through the series circuit containing choke IS, the secondary of a modulation transformer 2i, and a test jack 22. Jack 22 provides a connecting means for a meter while tuning this stage of amplification.

Modulation of the radio frequency is accomplished by impressing the voice frequency upon the grid of a tube 23, the plate circuit of which is connected to the grid of a tube 24 in the next stage of amplification. The plate of tube 24 is connected to the primary of a transformer 25 the secondary of which is connected through a push pull circuit 26 and 21 to the primary of modulation transformer 2!. The secondary of this modulation transformer is connected, as

above described, into the plate of tube l1 and in this manner the voice frequency is superfinposed upon the carrier frequency.

The modulated radio frequency currents thus created in the primary coil [9 of a radio frequency transformer 30 induce a current'flow in its secondary which is in the antenna circuit. This antenna circuit is grounded through condenser SI and the desired signal is thus broadcasted on the fire and police frequency to the fire and/or police authorities.

The above described circuit is designed to be compactly mounted within a suitable tamper proof casing and'all the necessary leads are brought to a central point where they are connected to a socket element 32a of the multiple point plug connector 32. The controlling means, responsive to the burglar and fire alarm circuits of the building, is adapted to be connected by the other element 32 of this plug connector to the radio transmitting set to cause its operation when need be. 1 The controlling means for causing the operation of the transmitter and alarm message reproducing means, is a system of relays connected between the fire and burglar alarm circuits and the radio transmitter. An electrical pickup impresses a recorded alarm message on the audio stage of the transmitter, the particular message which is broadcast depending upon which alarm circuit is disturbed. If both circuits are disturbed the two messages will be broadcast in alternating relation. In referring, in the claims, to a disturbance of a burgler circuit, it is meant the aifecting of the circuit, in a manner appropriate tov the particular circuit, to disturb its normal current condition so that it is conditioned to cause operation of the alarm signal means.

The fire alarm circuit through the building is normally open and the burglar alarm circuit normally closed, as here shown. When the building is closed for the period to be protected the apparatus is set and through the circuit described below relays are actuated to caus the operation of the alarm message reproducing means and the transmitter. A support bar provides a row of suitable contact points or terminals A to J and the controlling circuit is hooked up through these points in the following manner:

A battery is connected with its plus terminal to points F, H and J and with its minus terminal to point E, the negative side of the burglar and fire alarmsbeing connected to point E also. From point J a lead is provided that normally supplies current through contact 34 to relay 33, to point I which forms the positive or current supply terminal for the normally closed burglar alarm circuit, The positive terminal of th battery is connected to th point H which is connected through normally deenergized relay 52 to point G.

The fire alarm circuit is connected across points E and G, this circuit normally being open a potential is established across its terminals such that a current will flow when the circuit is closed. Point F is connected to the normally open contacts 36, 40 and 53. Whenever either one of contacts 36 or 53 is made the circuit continues through relay 38, stop switch 39 back to point E. If the contact 40 is made the circuit continues through contact 4| to point C. The contact C is connected to the motor of a motor generator set which motor is grounded to point D which is connected to point E. Connected in parallel between points C and D are the motor 45 of the sound reproducing means and a supply for the filaments of the tubes of the transmitter which supply is connected to contacts 46 and 41 of plug element 32.

The positive side of the generator of the motor generator set is connected to point A, the negative side to point B. Point A is connected to contact 43 of plug 32. Point B forms a ground for the pick up arms 53 and 5|. The pickup 53 is connected into circuit through the transmitted by contact 31 of relay 33, one side of the contact 31 being connected to contact 48 of plug 32. Pick up 5| is connected to contact 54 of relay 52, contact 54 being connected in parallel with contact 31.

This hook-up being established, the apparatus operates in the following manner:

When neither the fire nor burglar alarm circuits are disturbed the relay 33 remains energized by holding contact 34 closed establishing an energizing or holding circuit through battery 35 and relays 38 and 52 remain deenergized. This condition will prevail until the burglar alarm circuit in series wtih the battery and relay 33, is broken or the fire alarm circuit is made.

When the burglar alarm circuit is broken, it being in series with the battery and the relay 33, the current supply to the relay is stopped. Consequently the relay is deenergized and contact 34 is broken. While at the same instant contacts 33 and 31 are made. The breaking of contact 3a deenergizes relay 33 to again become operative it must be manually reset. When contact 36 is made current is supplied from the positive terminal of the battery, to a circuit containing a relay 33 and a stop switch 39 back to the negative of the battery. The energization of relay 38 makes contacts 40 and 4|. The contact 40 being connected to the positive of the battery, a current supply circuit is established through contact 4| to the motor of the motor generator set l6, which is grounded to the battery and the generator is operated to supply a suitable current (400 volt) to the radio transmitter through contact points 43 and 44 of plug member 32. Being connected in parallel with the motor circuit of the motor generator Hi, the small motor 45 arranged to drive a turn table and the current supply through contacts 43 and 41 of plug 32 to the filaments of the radio transmitter tubes. these elements of the system are rendered operative by the closing of contacts 40 and 4|.

A record, as disclosed in the copending application of William L. Foss, Serial No. 189,013, filed February 5, 1938, having two separate sound tracks is in position on the turntable and each track cooperates with a suitable electrical pickup. The two tracks are provided on one record so that from one track a message that the building is being broken into may be reproduced and from the other a message may be reproduced to the effect that fire has been detected. The recordings on the different tracks are so related that in the case where both burglar and fire messages are required, first the burglar message will be given, then the fire message, the alarm messages will alternate in this manner until the sound reproducer is stopped.

Electrical pickup heads and 5|, here assumed to be of magnetic or static type, are mountend on the usual swingable arms so as to be able to follow the burglar and fire message tracks respectively. As above stated the deenergization of relay 33 causes contacts 36 and 31 to be made. The circuits established by contact 36 prepare the radio transmitter for operation. The making of contact 31 connects the burglar message pickup 50 into a circuit through the plug 32 to the grid of tube 23, of the audio frequency stage. The transmitter already being in operation the appropriate message reproduced through pick up 50 will be broadcast to the police authorities.

Referring to the condition of the alarm system when it has been properly set for guarding the building it will be remembered that the relay 33 is energized holding contacts 36 and 31 broken and making contact 34. In this circumstance when the fire alarm circuit is made, i. e. when a thermostat in the circuit is heated to such a temperature indicative of fire that it closes the circuit, a current is caused to flow in relay 52 such that it is energized, making contacts 53 and 54 which under normal conditions are always open. Relay 33 is still energized and maintains contact 34 closed and 36 and 31 open. Pick up 50 is withheld from operation while the fire message is sent because contact 31 is held open. Making contact 53 supplies current to the circuit containing relay 38 which, as above set forth, starts the transmitter and turntable. The making of contact 54 establishes a circuit through the fire message pickup 5| and the grid of tube 23 of the audio-frequency stage of the transmitter so that a message is broadcast calling attention to a fire within the protected area.

In such an event that burglar and fire alarms should both be disturbed the relay 33 is deenergized and relays 38 and 52 are energized. The deenergization of relay 33 sets the transmitter in operation and establishes a circuit through pick up 50. The energization of relay 52 establishes a circuit through pickup 5|. The transmitting set under these circumstances having both pickups in circuit with it, broadcasts both messages. The record from which these messages are being reproduced having the two nonconflicting series of tracks as above explained, the alarm messages do not interfere with one another.

If the transmitters should accidently be set in operation, in order to prevent false alarms being sent out a stop switch 39 is provided. It is possible by operating this switch to break the current supply through the relay 38. When this happens contacts 43 and 4| are released and break contact, the current supply to the motor of motor generator H5 is stopped, and the transmitter is thrown out of operation. It is, of course, obvious that the set and the switch would be situated in some concealed position to render it inaccessible to unauthorized persons.

Whenever the protective system has been called into action it will continue to broadcast for a predetermined period of time. In the present invention a stop mechanism associated with the turntable and actuated by either of the pickup arms when it reaches the end of its track functions to operate the stop switch 39. This, as above explained, stops the motor generator set and renders the transmitter system inoperative. In order to again condition the set for operation, it is necessary to reset the relay control system. This is done by closing the burglar alarm circuit and/ or opening the fire circuit making it possible to reenergize relay 33 by making contact 34. The pickup arms 50 and are now reset to the start of the respective tracks and stop switch 39 is reset. The system is again in readiness and is operative to render protection to the building.

The relay control system like the transmitter is compactly designed to fit within a tamper proof casing and has all of its leads that cooperate with the transmitter brought out to the plug element 32 of the multiple connector. The other leads of the control system, which are connected to the burglar and fire alarm circuits, the battery and the motor generator set are brought out to the terminal support bar for convenience in hooking up the protective system.

From the foregoing description it is clear that any building to be protected by this apparatus is first wired with properly designed fire and burglar alarm circuits. These circuits are connected to the terminal support bar of the concealed control unit and the control unit is plugged into the transmitter unit. As soon as a battery and motor generator set have been connected up, the system is in condition for operation. compact, and simple broadcasting station is situated in the building to be protected and the unit is effective to automatically call the police or fire department upon any tampering with the building.

It will be obvious to those skilled in the art that the various alarm circuits may be interchanged, for instance the fire alarm may be normally energized and the burglar alarm may be normally deenergized. This possibility is intended to be included within the scope of the appended claims.

I claim:

1. A radio alarm apparatus comprising a plurality of alarm circuits including a normally energized relay and a normally deenergized relay; another circuit including a normally deenergized relay; said first named relay normally holding said other circuit open; said other circuit including also a stop switch, an alarm message reproducing means having available a plurality of alarm signals adapted tobe selectively reproduced in timed sequence, and a transmitter in connection with said reproducing means; and means connected to said alarm circuits and their respective relays whereby a disturbance of said circuits will cause the energization of said last named relay; and means connected to said last named relay arranged to be actuated by such energization to cause the operation of said alarm message reproducer and said transmitter to effect a broadcast of the selected alarm message.

2. A radio alarm apparatus comprising a plurality of alarm circuits including a normally energized relay and a normally deenergized relay;

By this means a thoroughly reliable, e

another circuit including a normally deenergized relay; said first named relay normally holding said other circuit open; said other circuit including also a stop switch, an alarm message reproducing means having available a plurality of alarm signals adapted to be selectively reproduced in timed sequence, a transmitter in connection with said reproducing means, and a motor 3. A radio alarm apparatus comprising a plurality of alarm circuits including a normally energized relay and a normally deenergized relay; another circuit including a normally deenergized relay; said first named relay normally holding said other circuit open; said other circuit including also a stop switch, an alarm message reproducing means having available a plurality of alarm signals adapted to be selectively reproduced in timed sequence, and a transmitter in connection With said reproducing means; a separate electrical pickup for said alarm message reproducing means associated with each of said first named relays; an interrupted circuit through each of said pickups, its associated relay, and said transmitter; either of said interrupted circuits being closed as a result of an actuation of its associated relay, the closing impressing the alarm message picked up on the transmitter; and means connected to said alarm circuits and their respective relays whereby a disturbance of said circuits will cause the energization of said last named relay; and means connected to said last named relay arranged to be actuated by such energization to cause the operation of said alarm message reproducer and said transmitter to efiect a broadcast of the selected alarm message.

4. A radio alarm apparatus comprising a plurality of alarm circuits including a normally energized relay and a normally deenergized relay; another circuit including a normally deenergized relay, and a stop switch; said energized relay normally holding said other circuit open; said other circuit including also an alarm message reproducing means having available a plurality of alarm signals adapted to be selectively reproduced in timed sequence and a transmitter in connection with said rep-reducer arranged to be actuated as a result of energization of said last named relay; a disturbance of any one of said alarm circuits acting to energize said last named relay; an interrupted parallel circuit through said first named relays arranged to be closed as a result of the actuation of either of said first named relays whereby an appropriate alarm message may be selected and impressed upon said transmitter to cause the message to be broadcast to the proper authorities.

5. A radio alarm apparatus comprising a plurality of alarm circuits including a normally energized relay and a normally deenergized relay; another circuit including a normally deenergized relay; said first named relay normally holding said other circuit open; said other circuit including also a stop switch, an alarm message reproducing means having available a plurality of alarm signals adapted to be selectively reproduced in timed sequence, and a transmitter including a plurality of tubes in connection with said reproducing means; a plurality of circuits in parallel with said other circuit; said parallel circuits including a circuit through a motor to drive said alarm message reproducing means and a circuit through the filaments of said transmitter tubes; and means connected to said alarm circuits and their respective relays whereby a disturbance of said circuits will cause the energization of said last named relay; and means connected to said last named relay arranged to be actuated by such energization to cause the operation of said alarm message reproducer and said transmitter to efiect a broadcast of the selected alarm message,

6. An alarm system comprising a transmitter, a pair of record portions having reproducible sound recorded thereon, a pair of pick-up devices vof which one is associable with one of said portions and of which the other is associable with the other of said portions, each of said portions being formed with alternate active and inactive sections, a motor for driving said portions, a burglar circuit and a fire circuit, means controlled by each of said circuits for rendering said motor effective to drive said portions, means controlled by one of said circuits for placing one of said devices in operative connection with said transmitter whereby to broadcast a certain signal, and means controlled by the other of said circuits for placing the other of said devices in operative connection with said transmitter whereby to broadcast a signal distinguishable from the first, one of said devices being operatively associable with an active section of one of said portions when the other of said devices is operatively associated with an inactive section of the other of said portions whereby with said devices in continuous association with the respective portions and both in operative connection with said transmitter, sound is reproduced alternately from the two portions.

JAMES O. HOWTON.

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