US2644937A - Apparatus for the transmission of alarm signals - Google Patents

Description

.July-'7,1953

L. cHAuvEAu APPARATUS FOR TRANSIYSSION OF ALARM SIGNALS originai man aan. 1s, 1941s 2h sheetssnee' 1 Uv f m M w CU l M k My 7,1953 f L. aM-uvm l 2,644,937'

Ppmms Fon .was mummy original ama' am. '13, 194e fishivsht 2 BYA l A A (L41 A )TOR/Vf' y Patented July 7, 1953 APPARATUS FOR THE TRANSMISSION 0F ALARM sIGNALs Louis Chauveau, Paris, France, assignor to Societe Franaise Radio-Electrique, a corporation of` France Original application January 13,' 1948,' Serial No.

1,976, now Patent No. 2,533,765, dated December 12, 1950.

Divided and this application August 2, 1950, Serial No. 177,267. yIn France January 29, 1947 2 Claims. (Cl. S40-345) The purpose served by alarm-selecting apparatus installed in ships is to release an acoustic warning device when the regular alarm signal is received by the radiotelegraphic receiver of the ship. This regular signal is composed `of a series of twelve dashes of fourv seconds duration separated by intervals of one second. The

selector must respond rto three or four consecue tive dashes. y l n This regular signal is keyed manually, so, as to be sent out, by the operator of the shipm distress. Generally, this .Y operator uses as a guide or check a clock or Watchv with a secondhand for checking his keying. As a result,kthe

dashes and spaces actuallytransmitted .are notr so accurate as they should be. p

To allow for this inaccuracy, the limits of a correct dash had been tolerated to be 3-5seconds, Whereas spacing could attain 5 seconds time. Thus, there is a large probability of reception of a signal formed by hand more or less correctly.

Recent regulations `have made the abovelimits narrower and at .the present time the correct dash must be comprised between 3.5 and 4.5 seconds duration and spacing must ,not be'over 1.5 seconds. Because of-this accuracy, ythe modern auto-alarm selectors require as a ,conse-y quence, more accurate. keying bythe operator. If one considers the circumstances of distress, it is obvious that risks of non-reception of an alarm signal are considerably increased., j y

The purpose of my present invention is toprovide a remedy, to a certain extent, to the aforesaid drawback. It essentially consists in making reversible the auto-alarm apparatus, i. e.,` in' permitting of using them either as reception selectors, Aor automatic transmission keying systems.

This application is a division of ymy application' Serial Number 1,976, iiled January 13, 1948 for Selector Apparatus for Alarm Signals, nowiPatent 2,533,765, dated December 412, 1950. v

For indeed, the auto-alarm selectors include all the necessary members for controlling spaces and dashes with accuracy; consequently itwill suffice to adapt them in ak suitable manner so as to make them control a keying relay which actuates the transmitter of the ship in such manner that 'the dashes have four seconds duration and spaces one second, the result being readily Yobtained Within a precision of the order of le of a second. Under thesefconditions, in any vessel equipped A with an auto-alarm selector provided withthe improvementv in conformity with the invention, it will be possible,- if need be,

. tov transmit ,thev alarml signal with they utmostr possibleaccuracy.` y I `,The invention is particularly concerned with the adjunction to'existng auto-alarmgselectors, of `devices v,pemiitting Vof combining the various members of the selector in such manner that the duration of the complete cycleis of 5 seconds and second. In addition, one may eventually provide a member Whichstops they system after the transthe control ofthe transmission is interrupted during' one second .in the course of each cycle;

the"disposition being such, moreover, that the,

transmitter thus controlledtransmits dashes of four `seconds duration separated by spaces ofv one mission of. twelve dashes of four seconds.

There is hereinafter given, by way. of anonlimitative'example, the 'description of an embodiment of my invention adapted to be applied to an apparatusior the transmission of alarm signals, said apparatus being v,*diagrammatically of the reception lof every dash. This relay,V showny more particularly in Fig. 2, has a period v of the orderof one second. It controls by way of its lcontact 8 the chain'of relays shown rin Fig. 1 at 'T1-AT1 to T4TAT4 in such ymanner thatv when-the durationbf a dash received becomes as great as 3.5 seconds, the contact 28 and T4 is closed and feeds to the Viirst set vof recording relaysv Ei-AEi, which "keeps being energized so long as the alarm signal received is correct.

At the time of the second'dash, the recording is eiected on relays E2-AE2. At the time of the third dash, relays Es--AEa operate and the alarm warnillg'y devices SNv are set intol action. When 'a dash lasts for 415 "seconds, thus being 3 incorrect, a relay T is energized by the fifth pendular impulse; then this relay T5 through Contact 3l cuts off the general power supply of the system, setting the whole apparatus to standstill.

When relay AT4 works, that is when a correct dash has just been received, the contact 32 supplies a system SIL of slugged relay with capacitor 33 and resistor 34, the whole having a time constant of 1.5 seconds; as a result, at the end of a correct dash, SIL maintains the whole being supplied so long as silence does not last more than 1.5 seconds.

The starting-up of the above system is promoted at the beginning of each dash by the slugged relay DM, itself controlled by the reception relay RR.

I provide in the circuit a switch I, a starter relay CEM, and a relay RM, which keys the transmitter when it is energized. The relay E1 must be fitted with an extra back contact A and relay T5 must be fitted with an extra make contact B. The additional elements are connected to the preselector comprising the invention as shown in the broken line wiring diagram of the drawing.

As can be seen, the switch I closes the circuit of the relay CEM. The latter carries a changeover contact C which transfers the circuit of DM from contact 1 of RR to make it connect by way of contact B of T5; this relay CEM is also fitted with a make contact D which short circuits part of the resistance 34. As a result of this short circuiting, the time constant of the assembly, relay SIL, condenser 33 and resistance 34, is reduced from 1.5-0.5 seconds. The operation of the apparatus is now as follows:

supposing that at the instant of closing switch I the relay RR is unenergized, the relays RM and CEM will operate; the latter by its contact C tends to supply DM; but the contact B of T5 being open, DM remains at rest. The voltage divider 2 is therefore supplied with power, the intermittent contactor I operates, transmits an impulse 0.1 second after receiving its starting torque, and the network relays Tr-ATi to T4-AT4 close step by step.

On the fourth impulse of the intermittent contactor, that is to say a time period of 3+0.1=3.1 seconds after the closing of switch I, relay E1 operates and the contact of relay RM opens. At the same time the shunt network, SIL condenser 33 and resistance 34, charges up.

At the fifth impulse, relay T5 operates, cuts the general supply (voltage divider 2) and locks on by way of the contact of relay SIL.

The relay T5 by its contact B provides for the energizing of DM which opens its contact 5. The energizing of relay T5 is assured by the contact of SIL for a period of 0.5 second, after which, relay SIL and relay T5 are energized. 0.4 second after the deenergizing of relay SIL, DM drops off, the

l voltage divider is again energized, and the whole cycle of operations described above is repeated. This condition persists as long as the switch I is closed.

The synchronously oscillating relay or intermittent contacter I, shown in Fig. 2, is constituted in the following manner: A flywheel 9 mounted on a shaft I0 to which is attached the spiral spring I I constitutes a balance wheel whose period is of the order of l second; that is to say it makes two half oscillations per second. The shaft is supported in two bearings I2 and I3. In order to promote starting up and to ensure the oscillation of the balance wheel, this wheel carries a magnetic portion I4, which is attracted by the solenoid I5, the circuit of the latter being controlled by the contact I6, the latter contact working under the action of an arm I1 integral with the shaft. The whole is contrived in such a way that contact I6 is not closed by arm I1 other than when the balance wheel is displaced in a clockwise direction, contact I6 being open when a movement takes place in the other direction. The wheel carries another arm I8 which controls contact I8 under the same conditions.

The shaft I0 carries a hanged collar I9 with a rounded notch which engages the roller 20 carried by lever 2| which rotates about a shaft 25. A spring 22 pulls in this lever so that it maintains the balance wheel in its position of rest. The lever 2l can be displaced by the solenoid 23 so that it frees the balance wheel and allows it to go into action.

To obtain a good performance from such an intermittent contactor it is essential that the magnetic portion I4, the solenoid I5 and the contact I6, are in well dened positions in relation with each other.

'I'hey must not therefore be displaced from these positions. On the other hand contact 8 can be displaced ina slot 24. It is therefore possible to obtain an advance or'retard in relation to the balance movement by the positioning of the contact which ensures very precise adjust ment of the measure of duration of a dash, as will be explained by the following:

This positioning of the moving contact 8 constitutes another feature of the invention.

Normally, in balance wheel devices of this kind, the whole is adjusted so that, when at repose, that is to say at the engagement of roller 20, the arm I1 .is a little behind contact I6; the spiral spring I I is then lightly wound up in such a way that when unlocking takes place, the arm I1 under the inuence of the spiral spring makes contact I6, whence an impulse of current travels to the solenoid I5, and the system starts operating. However, this method of starting-up is precarious, the useful torque of the balance wheel being very small at the moment of starting-up.

Another feature of the invention lies in the association of a balance wheel with a torque relay LAN, these two elements being interconnected according to Fig. l.

'Ihe relay LAN is disposed in such a way as to impart a strong current impulse to the solenoid I5 at the moment of unlocking, and up to the time of the establishment of contact I6; at this moment the relay LAN operates so as to include the contact I6 in the circuit of the maintaining solenoid I5. A resistance 25 allows control over the intensity of the impulses to obtain correct and continuous functioning of the oscillating relay. At the moment of the transmission of a dash, circuit A is switched on with a lag 0.4 second, the unlocking relay 23 operates freeing the balance wheel of the oscillating relay; at the same time the maintaining solenoid I5 is fed by Way of contact 26 of relay LAN which is not yet energized. A strong impulse drags the balance wheel in a clockwise direction until arm I1 closes contact I6; this latter then feeds relay LAN which closes and locks on by its contact 21. Contact 26 connects the solenoid circuit I5 to the resistance 25 and contact I5.

It is thus evident that the balance wheel receives a first and strong impulse, which ensures prompt starting-up and that it maintains its v oscillation under the action of suitably regulated impulses transmitted by contact lli.k

At each oscillation contact B'is closed. At the first oscillation its closing takes place abouti); second after the commencement l of oscillation of the balance wheel. It controlsl the circuit of the relay network 'T1-T4 togetherwith thatofthe auxiliaries AT1-ATi in such away that one'set of relays is energized at each impulse.

In light of the foregoing, each cycle of the alarm transmitter can be split up into four periods: one period of 0.1 second, corresponding to the delay in the transmission of the first impulse by the intermittent contactor; one period of 4 seconds corresponding to four complete oscillations of the intermittent contactor, a period of 0.5 second or drop-off-lag of relay SIL, and a period of 0.4 second corresponding to the lag in droppingoff of relay DM. This gives a total of 0.1-}-4-i0.5+0.4:,5 seconds which represents the working cycle of the transmitter. 1t must be observed that energizing of relay T4 eiTects the energizing relay of relay Ei, while relay T5 effects the deenergizing of the latter.

As a result during the course of each cycle, the

keying relay RM, whose supply is controlled by contact A of relay E1, will be energized for 4 seconds, and will be at rest forl second. Finally, relay RM by way of its contact keys the transmitter.

It can be seen that the apparatus thus constructed ensures the continued transmission of 4 second dashes separated by spaces of 1 second.'

Eventually, a twelve contact telephone stepper switch (not shown) may be connected in parallel with RM, or be controlled by the latter, so that after the tenth dash, this stepper breaks the circuit of CEM, thereby terminatingr transmission.

The auto-alarm selecting apparatus which comprises a stabilized, constant speed motor are equally lcapable of being improved by using the device of the invention. 'In the case of such apparatus however, it is simpler-to'adjoin them to a cam driven by the motor and arranged so as to directly control the appropriate transmission;

but it can always be of advantage to adjoin them with the device which is the subject of this invention, so as to permit of stopping the whole system after transmission of twelve dashes.

It will be understood that the examples of application which have been given hereinabove are in no way limiting, and the invention may apply, totally or partly to various types of autoalarm selectors or any other like apparatus within the scope of the appended claims,

What I claim and desire to secure by Letters Patent of the United States is as follows:

l` In a device for transmitting radio-telegraphic signals composed of a series of dashes of a given duration separated from one another by spaces of another determined duration, a di-l rect current power supply, a potentiometer, three electromagnetic relays each having a contact member, said potentiometer being fed from said power supply through the contact members of said three different relays, a mechanism with pendular oscillations, means for normally blocking said mechanism, means for unblocking said mechanism when the potentiometer is connected to the power supply, means connected to the potentiometer and adapted to impart to said mechanism a constant oscillation period equal to the space duration of said signals and being a submultiple of the dash duration of said signals, a chain of interconnected countingrelays, a line connected to the potentiometer, adjustable means cooperating with said line and with the said Vmechanism to connect said line to the relays,said

means, including a member producing one pulse ing relay-andadapted to connectthe recording relay to the said potentiometer, a relay controlling the transmitter operation, means to conl nect said last mentioned relay to the power supply through a resting contact of the recordingY n relay, means for periodically opening the circuit to said potentiometer and power supply, said lastmentioned means including three relays each having an armature rand coacting contacts respectively designated make-and-break cut-off, silence, and starting relays controlling the three aforementioned contacts, and connecting the potentiometer to one terminal of the power'supply, the two silence and startingv contacts being mounted in parallel, and connected in series with the contacts of the third make-and-break cutoff relays, which separates them from the potentiometer, means associated with the silence relay and with one of the contacts of the last counting relay to actuate the silence make-contact opening with a given time delay, the beginning o f the delay period coinciding with the opening of the potentiometer supply circuit, means associated with the starting relay, with a make-contactof the cut-off relayfand with the supply circuit of the potentiometer, which are adapted to tact, means associated with the potentiometer supply circuit and another contactmember of the last counting relay, which are adapted to bring the cut-off relay excitation andthe bef ginning of the self-excitation of the silence ret lay in coincidencewith the pulse immediately following the one-which caused the last counting relay to be energized, means associated with the make-and-break contact of the cut-off relay and Vwith one of the terminals of. the power supply to hold saidl cut-off relay energized after the displacement of itsarmature, which keffects the opening of said supply circuit, and means for causing the sum of the two said delay timesand of the time-interval between the pendular mechanism unblocking'andfthe first control pulse, to equal the oscillation period of said pendular mechanism.

2. A device for transmitting radiotelegraphic sigk nals `as set forth in claim 1, in which said mechanism with pendular oscillations includes a dynamically balanced flywheel having a projecting lug thereonV made of a non-magnetic metal and having a vertical shaft, unblocking means comprising acam mounted on said shaft and con operating with a lever adapted` to turn about 7 holding line through one of the contacts of said relays, a flexible contact closed by the said lug during the flywheel rotation., and adjustable mea-ns adapted to adjust the angular position of this lug respectively to the contact in a given position of the flywheel.

LOUIS CHAUVEAU.

References Cited in the le of this patent UNITED STATES PATENTS Number

Images