US2462875A

US2462875A - Automatic alarm signaling system

Info

Publication number: US2462875A
Application number: US549561A
Authority: US
Inventors: Jr William Cobb Lane
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC; Federal Telephone and Radio Corp
Priority date: 1944-08-15
Filing date: 1944-08-15
Publication date: 1949-03-01
Anticipated expiration: 1966-03-01
Also published as: GB611219A; FR915181A

Description

March l, 1949. w. c. LANE, .JR

AUTOMATIC ALARM SIGNALING SYSTEM 2 Sheets-Sheet l Filed Aug. 15, 1944 arch 1949- w. c. LANE, JR 2,462,875

AUTOMATIC ALARM SIGNALING SYSTEM Filed Aug. l5, 1944 2 Sheets-Sheet 2 Patented Mar. l, 1949 UNITED STATES PATENT OFFICE AUTOlVIATIC ALARM SIGNALING SYSTEM William Cobb Lane, Jr., Belleville, N. J., assignor to Federal Telephone and Radio Corporation, New York, N. Y., a corporation of Delaware Application August 15, 1944, Serial No. 549,561

l1 Claims. 1

This invention rel-ates to an automatic alarm signalling system and particularly to an automatic alarm signalling system for marine distress calls, including a selector unit responsive to a predetermined distress call and a transmitter unit adapted to transmit said distress call.

Some objects of the present invention are to employ simple, standard, rugged equipment and to set the apparatus in motion only when needed, thus avoiding continuously moving parts and the Wear incident thereto.

Other objects of the invention are to provide an automatic system which requires a minimum of overseeing by the operator, the performance of which is highly reliable and which may be made responsive to varied distress calls.

These objects have been achieved by providing a selector unit including a receiver, means to produce a sequence oi impulses arranged in predetermined time relation, a counting means operated When the impulses produced bear a certain time relation to the signals received, `and an alarm device operated after the counting means has counted a certain number of times. There is also provided a transmitter unit including means to produce a sequence of impulses having a certain time relation with the impulses produced by the selector unit and a transmitter keying circuit responsive to these impulses. The impulse producing means may comprise a vibrating relay adapted to swing back and forth between tWo iiXed positions, in one of which it closes the contacts of a circuit which in the selector unit opcrates the counting means and in the transmitter unit the transmitter keying circuit.

The invention will be more fully explained in connection with the following description and the annexed drawings, in which:

Fig. l is a circuit diagram of a selector unit for an 'automatic alarm signalling system made according to the invention;

Fig. 2 is a graphic representation of a suitable distress call to be used in connection with the system; and

Fig. 3 is a circuit diagram of a transmitter unit for the system.

The selector unit may have the form shown in Fig. l and may include a receiver (not shown), a relay I responsive to received signals, an impulse producing means which advantageously comprises a vibrating relay 2, means for initiating the operation of the impulse producing means, such as a magnet 3, for attracting the vibratory arm d, -a counting means for counting the impulses so produced such as a stepping relay 5 car rying an arm 6 which moves a certain distance for each impulse counted, an alarm device such as a bell which is operated `after the counting means has counted a certain number of impulses by means of the arm 6 closing the circuit of the alarm device, and a power source such as a battery 1.

The relay i may advantageously be provided with a plurality of contacts 8, 9, I, and II of which contacts Il are normally closed When the other contacts are open.

The vibrating relay 2 may consist of a spring 4 mounted at one end in a block I2 of conducting metal such as brass, Which is connected to the negative post of the battery l. The spring is attached at its opposite end to a suitable Weight I3 and also carries a soft iron armature I4 and a set of Contact buttons l5. The spring is adapted to vibrate between positions A and B, shown in dotted lines, and to alternately engage by means of its contacts i5 similar buttons IE and I'I mounted on two supporting springs at either side of the spring Il. The spring and weight I3 are selected so as to produce a sequence of impulses arranged in a predetermined time relation, the number of impulses produced being at least equal to the numbers of steps in the stepping relay.

The movement of the spring 4 may be initiated by means such as the magnet 3 Which is arranged to attract the armature I. The circuit of the magnet 3 includes in series the battery 1, contacts 9 of the relay l and contacts It made by the arm B.

The arm 6 is carried by the stepping relay 5 and each actuation of the latter causes the arm to move a certain distance. The arm S is arranged in starting position to close contacts I3 of the magnet circuit and to open them on movement away from starting position. In final position the arm 6 is arranged to close contacts I9 of the alarm circuit.

The stepping relay 5 may be energized either by the actuating coil 2t or the release coil 2|, depending on conditions. Each time the coil 20 is energized the arm moves a unit distance; each time the coil 2| is energized the arm drops back to its starting position. The relay 5 is advantageously of the indirect action type, i. e., the relay steps at the iinish of the actuating impulse.

It will be seen that the contacts B of the relay l and the contacts I5, it of the relay 2 are in scries and depending on conditions may complete a circuit to the coil 2t. Similarly the contacts It and the contacts I5, Il are in series and may complete la circuit to the coil 2l. Contacts II are in series with contacts I5, B of the relay 2 when contacts 8 are open, providing a circuit to the coil 2|.

The alarm device may comprise the bell and a circuit therefor across the battery including contacts I9. Means for maintaining the bell operative in the event contacts i9 are opened by energization of the coil QI, may be provided. These means may comprise the relay 22 having contacts 23 and 2Q, and an alarm locking circuit across the battery to the bell including contacts 2d and bypassing contacts IS.

Resetting means for deenergizing the alarm device may comprise a two position switch 25 arranged in one position to connect relay 22 to the terminals of the battery and in the other position to disconnect relay 22 from the battery and simultaneously to close a circuit to the coil 2l, causing the arm 6 to drop back to starting position.

By properly constructing the vibrating relay 2 to produce a sequence of impulses arranged in predetermined time relation, the selector unit may be made responsive to a particular distress call comprising a sequence of signals to which the sequence of impulses bears a certain time relation. The simplest relation is to have the sequenceA of impulses produced by the selector unit identical in frequency and phase with the signals received thereby. A convenient distress call will consist of an initial dash, or characteristie signal followed by a series of dots, but this pattern may be varied by appropriate circuit modications. The duration of the call will depend on what balance is considered desirable between freedom from false alarms and certainty of operation on real alarms. Fig. 2 illustrates a convenient distress call of ten-second duration, consisting of a four-second dash followed by a. series of nine dots, with a dot frequency `of two per second. In conjunction therewith a stepping relay of ten steps is used. The three dots shown in dotted lines represent signals in excess of the num-ber required to operate the alarm device and are of no effect. Their occurrence depends on the construction of the transmitter unit about to be described.

While the distress call may be transmitted by various types of mechanisms, a particularly useful one is shown in Fig. 3 and includes a relay 2 identical with the relay 2 of the selector unit, a transmitter keying circuit (not shown) responsive to impulses produced by the relay 2', a magnet 3 for initiating the movement of the vibratory arm 4 and means for energizing the magnet 3 for predetermined time intervals either manually or automatically, as desired.

The spring 4' is mounted in the conducting block I2 and carries the weight i3', armature I4' and contact buttons l5. The spring i is adapted to vibrate between positions A and B' advantageously at the same frequency as and in phase with the spring t of the selector unit, and to alternately engage contact buttons l', il. The contacts I5', I6 are in series with the transmitter keying circuit.

o and contacts il to open.

The armature I4 is adapted to be energized by the magnet 3 which may be connected in series with the battery l and either the switch 26 or the switch 2l. The switch 2B may be operated manually; the switch 21 may be operated by means of the rotating cam 28 driven by the motor 29 which is powered by the battery 'I'. The motor 29 may be connected to or disconnected from the battery 'l' by means of the double contact switch 30, one of whose contacts is in the circuits of the magnet 3.

The selector unit above described operates in the following manner. k.Atransrriitted signal is demodulated and rectified-bythe receiver, and the rectied current energizes the relay I. The relay I is preferably arranged so that energization thereof causescontacts 9, and Ii) to close Energization 'of the relay I therefore closes the circuit of the magnet 3 which becomes energized and pulls over the armature I d to position A. Contacts I5, I6 are thus made, closing a circuit to the'actuating coil 20 of the relay 5. At the finish 'of the actuating impulse the relay 5 steps one notch moving its associated arm t to openthe magnet circuit. The magnet 3 is deenergized and the Vspring 4 isrreleased to commence. its vibrations voi predeter-` mined frequency. The spring l now swings over to position B, making contacts I5, I1. If, at this time a spurious signal should be receivedccntacts iii will be closed, completing acircuit to. the release coil 2l of the relay 5 andcausing the arm 6 to drop back to starting position.. vHowevenif, as is contemplated, there is no. signalat this time, Contacts l@ will be open and the release coil 2! will not be operated. The spring fl will 'now commence its second swing to position A.v Ifr atthis time a second signal is received,l the circuit to coil 2i) will again be closed and the relay 5 willstep. If, conversely, no signal isreceivedfat:thistime, ycontacts 8 will be open and contacts .Il closed, completing a circuit .to the release. coil V2l. Vand causing the arm S to Ydrop back to startingv position. It will thus be seen that the relay 5V can be stepped up to operate the alarm device' only when a sequence of -signals isreceived which have a proper phase and frequencyV` relation Ato.v the vibrations of the spring 4. Y

After the relay 5 has stepped a suiiicient num.- ber of times the arm t closes contactsl. Yof the alarm circuit. IThe relay 422; is, energized, closing

contacts

23 and 24 and thus the ,alarm locking circuit. Hence, even if the releasa coil 2-I`is now energized, the alarm device will continue in operation since-the relay v22 is energized through the alarm locking circuit. The alarm-device mayz--be put out of operation by moving the resetting switchk 25 to disconnect the rrelay v2.2 from the battery and to complete a circuit .to ther-release coil 2 l.

It is apparent that the selector `unit described is completely automatic, since the only thing: required to be done bythe operator isy to shut off the alarm device by moving the resetting switch 25. Certain features of the described selector unit ensure a high degreey of'reliability in performance. For example, since the magnet Skis open-circuited at the end of the iirst received signal, static crashes and other disturbances cannot cause out-of-phase signals to be sent through it, disturbing the timed vibrationsnf ,the spring 4. Storage of random signals is avoided kby the action of the spring 4 swinging back toposition. A and operating the release coilj2i in the event that the subsequent signal of the sequence is not received.

The selector unit also has a high degree of freedom from interfering signals and static, the eiect of which is to close relay I. If the interference occurs during the normal closure (by the distress call) of relay l, it is of no significance, since the relay is closed anyway. Closure of this relay while the spring 4 is at a point between positions A and B is also of no effect because the contacts of the relays I and 2 are in series; the circuit is held open by the contacts of relay 2. Interference has no eiect on the vibrational frequency or phase of the spring l since the magnet 3 is open-circuited by the arm 6 at the rst stepping of the relay 5.

The transmitter unit above described operates in the following manner. If it is desired to transmit the signals oi a particular distress call manually, the operator places the double contact switch 3U in the position shown and holds the push-button switch closed for a time interval correspending to the initial signal to be transmitted; he then releases the switch 26. Closing of the switch 26 completes the respective magnet circuit, energizing the magnet 3. Energization of the magnet 3 pulls over the armature lli to close contacts l5, l5', completing the transmitter keying circuit and transmitting the rst signal of the distress call. Opening of the switch 26 brealcs the circm't of the magnet 3', releasing the spring 4 to swing alternately between positions A, B, producing impulses of the same frequency as the predetermined distress call to which the selector unit has been made responsive. For the particular distress call illustrated by Fig. 2, the operator will hold the switch 25 closed for the nrst four seconds of each ten-second interval. To repeat the signal, the operator will wait at least six seconds (for automatic transmission of the remainder of the signal) and again close switch 26 for a four-second period.

If it is desired to transmit the signal sequence automatically, the operator opens the switch 25 and closes the double contact switch 3E, thus connecting the motor to the terminals of the battery. The motor drives the cam 28 which is arranged so that for a predetermined time interval of its cycle of rotation, the raised part of the cam closes the switch 22', completing the respective magnet circuit, while for the remaining period of the cycle of rotation the switch 2 remains open. For eX- ample, for the particular distress call illustrated in Fig. 2, the cam will be arranged to rotate once every ten seconds, or will have a speed or" 6 R. P. M. The raised portion of the cam will close the switch 21 for four seconds out of the tensecond duration of the distress call.

It will be seen in the embodiment shown that since the relays 2 and 2 of the selector and transmitter units respectively are identical, the transmitter unit will transmit the sequence of signals to which the selector unit is responsive.

Another advantage of the described transmitter unit is that by providing the vibrating relay of the selector unit with any appropriate switches it can readily be connected for transmission purposes. One possible switching means is indicated by the leads at various points in Fig. 3. Hence each vehicle need only be equipped with one such relay in order both to send and to receive distress calls.

The system is not necessarily restricted to marine distress calls but is applicable to other moving vehicles such as planes from or to which it is desired to send alarms. The system is also applicable for sending alarms over wire transmission lines. Another application is that of a call system used to contact individual boa-ts of a fishing fleet, or one of a number of radio stationspolice cars, for example. In these applications a different call would be used for each station.

Although the invention has been described with particular reference to the embodiment shown, this has been done by Way of illustration rather than limitation.

What I claim is:

l. An alarm signalling system as set forth in claim ll in which a circuit is provided including in series said release coil, said contacts of the vibrating relay and contacts of said first relay arranged to be normally closed when the corresponding relay contacts of said control circuit are open.

2. An alarm signalling system as set forth in claim l1 in which a circuit is provided including in series said release coil, additional contacts of said rst relay and contacts of said vibrating relay in opposed time spaced relation to said firstmentioned vibrating relay contacts.

3. An automatic alarm system responsive to a plurality of impulses and spaces recurring at a predetermined frequency comprising a vibrating member arranged to vibrate at said predetermined frequency when initiated into operation, an impulse responsive relay responsive to the impulses and spaces and having contacts closed when the relay responds to the impulses and contacts closed when the relay responds to the spaces, counting means having a plurality of positions and means to advance it through said positions step-by-step, initiating means for said vibrating member including electromagnetic means, contacts operated by the vibrating member in its movement in one direction, other contacts operated :by the vibrating member in its movement in the other direction, a circuit including said electromagnetic means, contacts closed only in the initial position of the counting means and contacts of sai-d relay when it responds to an impulse, whereby said member is started vibrating by the rst impulse and is thereafter Vibrated in accordance with its own frequency, restoring means for said counting means, circuit means for said advancing means and said restoring means and including the contacts operated by the vibrating member in its opposite directions of movement and the relay contacts operated by the energization and deenergization of the relay for repeatedly operating the advancing means if the energization and deenergization of the relay correspond to the movements of the member in said opposite directions and to operate the restoring means if such correspondence does not obtain and signaling means operated by the counting means when the counting means is advanced to a given position.

4. An automatic alarm signalling system comprising signal receiving means, means to produce a sequence of impulses recurring at a rate independently of the rate of impulses received by said signal receiving means, means to initiate the operation of said impulse producing means in response to a characteristic signal received by said receiving means, a circuit responsive to both said signal receiving means and said produced impulses, a counting means in said circuit adapted to be operated thereby only when impulses received by said receiving means coincide with said produced impulses, an alarm device, and means top'rate said alarm device when said counting means has been operated a predetermined number of times.

5. A combined receiver and transmitter station for an automatic alarm signalling system comprising signal receiving means, means to produce a sequence of impulses recurring at a rate inde'- pendently of the rate of impulses received by said signal receiving means, means to initiate the operation of said impulse producing means in response to a characteristic signal received by said signal receiving means, a circuit means responsive ,to both said signal receiving means and said impulses, and including therein a counting device operable only in response to coincident ones of said received and produced impulses, means responsive to a predetermined number of operations of said counting device to eiTect an alarm indication transmission means having control devices, means for at times connecting said impulse producing means to said control devices, said control devices thereby operable to cause sending of said characteristic signal followed by the automatic transmission or" a sequence of impulses produced by said first mentioned means.

6. An automatic alarm signalling system including a seiector unit responsive to a sequence of signals arranged in predetermined time relatio-n and including a series of impulses recurring at a predetermined frequency, said unit including signal receiving means, a vibrating relay adapted when started to vibrate independently of imn pulses received by said signal receiving means, a second relay responsive to signals received in said signal receiving means, a starting circuit for said vibrating relay closed by said second relay upon receipt of a characteristic signal, a counting means including means to open said circuit at a predetermined step thereof, a circuit for repeatedly operating said counting means when the vibrations of said vibrating relay have a predetermined time relation Wit'n said received series of impulses including, in series, contacts closed by said vibrating relay during vibration thereof and contacts closed by said second relay when a signal is being received thereby, and an alanm circuit closed by said counting means when it has completed its cycle of steps.

7. An automatic alarm signalling system including a selector unit responsive to a sequence of signals comprising an initial dash followed by a series of dots arranged in predetermined time relation, said unit including signal receiving means, a relay responsive to signals received by said signal receiving means and including a piu- .rality of sets of contacts, a step relay of the type which steps at the end of an energization inn vcluding a contacting arm adapted to close a set of contacts in its initial position, a vibrating relay adapted when started to intermittently close a set of contacts in said predetermined time relation, a circuit to start said vibrating relay including, in series, one of the sets of contacts closed by said signal responsive relay during said` by said step relay when it has completed itscycl'e of steps.

8. An automatic alarm signalling systemrincluding a selector unit responsive to a sequence of signals consisting'of an initial vdash followed by a series of dots arranged in predetermined time relation, said unit including signal receiving means, a signal responsive relay having a plurality oi sets or" contacts adapted to be closed thereby upon receipt of a signal, a vibrating relay adapted when started to intermittently close a set of contacts in said predetermined time relation, a step relay responsive to: an actuating coil and a release coli, a contacting arm carried by said step relay, a set of contacts closed by said contacting arm only in its initial position and opened upon the first step of said step relay, a source of current, a circuit for starting said vibrating relay including in series said source of current, a magnet adapted to start said vibrating relay, one of the sets of contacts of said signal responsive relay and the set'oi contacts which is closed by said contacting arm in its initial position, a circuit for repeatedly operating said step relay including in series said source of current, said actuating coil, another set of contacts of said signal responsive relay and a Set o'f conts closed by said vibrating relay, anV alarm circuit adapted to be closed by said step relay, and a circuit means for resetting said step relay including said source of current and said release coil.

9. An automatic alarm signalling system including a selector unit responsive to a sequence of signals arranged in predetermined time relation, said unit including receiving means, a vibrating relay, a relay actuated by received signals, a circuit having contacts closed byfsaid latter relay in response to an initial signal condition thereof to energize said vibrating relay, a step relay adapted to operate through a cycle and also controlling said circuit, means associated with said step relay to break said vibrating relay energizing circuit at selected points of said step relay cycle, a circuit closed by said vibrating relay when the vibrations thereof have a predetermined time relation with the signals received and adapted on closing to energize said step relay, and an alarm circuit closed by said means after said step relay has completed its cycle of steps.

10. An automatic alarm signalling system including a selector unit responsive to a sequence of signals comprising an initial dash followed by a series of dots arranged in predetermined time relation, said unit including receiving means, a relay responsive to received signals, a step relay of the type which steps at the end of an energization, a contacting arm associated with said step relay, a vibrating relay, a circuit to initiate vibratory motion in said vibratory relay, said circuit having contacts closed by said signal responsive relay during said initial signal and c0ntacts opened by said contacting arm on the first step of said step relay, a circuit having contacts closed by said signal responsive relay when operated and contacts .closed by said vibrating relay when the vibrations thereof coincide with the received signals, said last-mentioned circuit being adapted on closing to energize said step relay and an alarm circuit closed in response t0 the completion of said step relay of its cycle of steps.

11. An automatic alarm signalling system including a selector unit responsive to a sequence of vsignals consisting of an initial dash followed by a series of dots arranged in predetermined time relation, said unit including receiving means, a first relay having a plurality of contacts, actuated by received signals, a vibrating relay, a step relay responsive to an actuating coil and having a release coil, a contacting arm carried by said step relay, a source of current, a starter circuit across said source of current including in series a magnet adapted to energize said vibrating relay, contacts of said rst relay and contacts made by said contacting arm, a control circuit across said source of current including in series said acuating coil, other contacts of said rst relay and contacts of said vibrating relay, an alarm circuit across said source of current said contact ing arm being adapted in at least one of its positions to close said starter circuit and in at least one other of its positions to close said alarm circuit, and a resetting circuit across said source of current including said release coil.

WILLIAM COBB LANE, Ja.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS