US1658953A - Signaling apparatus - Google Patents

Description

Feb. 14, 1923.

L. S; THEREMIN SIGNALING APPARATUS Filed Dec. 5. 1925 5 Sheets-Sheet 1 Fig.1.

III III! Feb. 14, 1928.

L. S. THEREMIN SIGNALING APPARATUS Filed Dec. 5, 1925 5 Sheets-Sheet 2 Fig. 13.

' W s I 277 J22 vlziorz We Y W a Feb. 14, 1928.

- 1,658,953 L. S. THEREMIN SIGNALING APPARATUS Filed Dec. 5, 1925 5 Sheets-Sheet 3 ff I Feb. 14, 1928.

L. s. THEREMIN SIGNALING APPARATUS Filed Dec. 5. 1925 5 Sheets-Sheet 5 J72 verzior:

By Mafia/ac,

Patented F elm l4, 1928.

" UNITED STATES PA'rsNr OFFICE.

LEO SSERGEJEWITSCH THEREMIN, OF LENINGRAD, RUSSIA, ASSIGTTOR TQ FIRM M. J. GOLDBERG AND SOHNE G. M. B. 31., OF IBEBLIN-CH ARLOTTEN'BURG, GER- MANY.

SIGNALING APPARATUS.

' a Application filed December 5,-1925, Serial No. 73,530, and in Germany December 11, 1824.

This invention relates to signaling and alarm devices and aims to provide a novel method of and means for generating sound on producing visual signals for alarm purposes. It embodies an electro-magnetic systern of high-frequency oscillation potential operable by the approach thereto of an object such for example as a person entering a roo when the apparatus is applied in a burglar 310 alarm system, a train approaching a signal block when applied in a railroad signaling system, etc. An apparatus embodying the invention may also be controlled by other factors, such as an increase of temperature when adapted in a fire alarm system, or by some other factor when appropriately applied to operate upon the happening of an anticipated disturbance'or event.

In other words, movement of an object or other variable factor in predeterminable relation to an, apparatus embodying the invention causes a variation in the self-inductance or capacity of the oscillating system thereof, which in turn brings abou'ta vari system and such frequency variation causes operation of the sound means. 1

An object of the invention is to provide an apparatus of the specified type, the operation of which will not be affect-ed by the variables to which related apparatus have generally been subject and to this end is de signed to respond not to variations of fre-' quencybut to an abnormal rate of such variation, and to operate only when such rate exceeds or fails to attain a certain value, as opposed to the normal rates of variation caused byc'ertain conditions hereinafter described. k

Apparatus of the general type to.which this invention relates have heretofore been operated by frequency variations and not by the rate at which such variations occur.- Such apparatus has been objectionable because it will .not operate properly without continual supervision and regulation. This fact is due to the influence of several factors which become so great in a comparatively short time as to interfere with the operation of-the apparatus.

i The defective conditions ation in the frequency of oscillation of the:

produceror signaling 1n such apparatus are either inherent therein and result from factors which influence the oscillations of the. electro-ionic oscillator preferably em-,

ployed, such for example as the heating, the plate potential, the vacuum, the electron emission',-etc., or are due to extraneous causes, such as atmospheric influences, temperature, the varying percentage of moisture in the walls or structures alon or in which the wires of the system are disposed, or to other similar causes. The influence of these variables is so great that. it cannot be compensated by the means ordinarily provided.

On the other hand, in an apparatus embodying this invention, the influence of such factors is eliminated by making the apparatus responsive to the rate of variation of the frequency, rather than to the variation of frequency. The influence of the aforementionccl variable factors is compensated by an appliance which may be termed a regulator which is operated at a certain speed, and the apparatus will respond only if the rate of variation of the frequency due to the ap,

proach of an objector other controlling factor is abnormal and exceeds that speed,

By such means, the apparatus is rendered independent of the variations of frequency which are due to said variable factors, does not require continual supervision and regulation, and will operate in areliable and satisfactory'manner.

he apparatus may be so designed as to respond under any desired conditions, for

instance, if applied toa building in a burglar-alarm system, it may be made to respond and signal an alarm as a burglar creeps within distance to influence the system even before entering the premises, because his body, upon approaching in proximity to the system,,will cause vibrations to be set up therein at a rate of frequency variation far greater than the rate of variation due to said variable factor. Similarly, if applied in a fire-alarm system, the apparatus may be made to respond only to abnormal -variations or sudden rise of temperature in the room wherein it is arranged, even if the actual temperature inbrease' is relatively small;

The regulator, which may be designed for any speed and-magnitude of compensatlng action,- will gradually and automatically vary its self-inductance or capacity and con sequently the characteristics of the oscillating circuit in such a manner as to obtain the desired result.

In the drawings, several forms of apparatus embodying the invention and operable according .to the method embodying the same are illustrated diagrammatically by waIy of example. I

. 11 said drawings,

- Fig. 1 is a diagram illustrating'the underlying principle of the invention; 3

Fig. 2 is a diagram ofa regulator;

Figs. 3 to 7 illustrate various heat-operated regulators;

Fig. 8 is a diagram of an arrangement wherein regulators according to Fig. 9 are employed;

Fig. 9 illustrates a mechanically operated regulator; x

Fig. 10 illustrates a modification of the regulator shown in Fig. 9;

.Figs. 11 to 15 illustrate various fire-alarm systems embodying the invention; and

Fig. 16 illustrates a complete installation comprising a-- central and three local protection stations.

In Figs. 1, 2-and 16, E represents a highvoltage battery.

For the purpose of disclosing the nature of the invention, Fig. 1 shows a system of connections in which variations of the natural period of an oscillating system 235 are caused by the variation of the capacity of an antenna. or control conductor connected to it. The antenna comprises a wire or flexible lead whioh'is supportingly extended along, around or within the area or district 40 to be protected. Said antenna has a definite normal capacity and this capacity is affected when a person such as a burglar or any object approaches it. The antenna is accordingly hereafter referred to as a control conductor and obviously may take various forms and be arranged in various ways dea pending upon the use that is made of the -An electro-lonic oscillator or generator tube 237 isin-ductively coupled to the oscillating circuit 235. The frequency of the oscillator 237 is adjusted to about the reso- .nance point of the oscillating circuit 235 by proportioning the constants of the asso- 5 .ciated oscillating circuit 236. .When the capacity of the antennas or control conductor isvaried-by the approach of aforeign object,

a corresponding variation of the amplitude of the oscillations of the oscillator 237 takes place resulting from and depending upon the difierence between the periods of the oscillating systems 235 and 236.

The variation of the grid'current in a grid-leak resistance .234 causes a variation of the potential on the grid of a second. tube 1 signaling apparatus.

'tion and v A s 238, and the plate current of the tube 238, which Varies accordingly, may be measured by the measuring instrument 239: If theoscillating systems 235 and 236 are so tuned i that a retardation of the natural'frequency of the circuit 235 brings about a reduction of the oscillation energy of the tube 237 an increase of the capacity of the antenna causes an increase of the plate current through the "measuring instrument 239, the increase being substantially proportional to the increase in' capacity. As long as the object to be detected is outside of theoperating range of the antenna, no variation in the deflection of the instrument 239 will take place. The plate current increases gradually in proportion to the rate at which the obgect approaches the antenna, until it 4 reaches its maximum value when the object has reached the antenna When the foreignbody or object moves'slowly towards the antenna, the increase of the plate current of the tube 238 proportionally takes place slowly and gradually. When. the movement occurs at a higher speed, the plate current rises at a correspondingly. greater rate.

Fig. 2 is a diagrammatical representation of the connections of the regulators; i. e.,

the devices which compensate for the normal plate current variations. ,The amplifier tubes 111 and 112, which correspond to the tube 238 in Fig. 1, are connected .to'a I heating winding. 113 instead of a measuring instrument 239. Said winding 113 isshown. disposed around an expansible metal core connected to a condenser 114. Said metal emanating from the heating winding 113 core expands under the action of the heat to move the plates of the condenser closer vtogether, whereby the capacity of the condenser is increased. If the condenser 11 i is appropriately connected in the circuit'of the oscillator tube 237, it will vary the capacityofithe oscillator circuit in such a manner as to compensate for the variation which has occurred in the antenna system if. this tion dueto the rapid approach of a foreign body towards the antenna, while if the capacity variationis sufliciently slow, the regulator is able to compensate for the varia prevent the production of a warning signal. 1

. Before giving a detailed description of a I complete installation, the construction of varlous forms of regulators, will first be described with reference to Figs. 3 to 7 of the drawings.

In these regulators, the con-- trolling current causes a slow. variation of .is supported on the larger portion of a twodiameter glass tube-135, 136 containing mercury. A thin metallic cylinder 137 is shown surrounding the larger portion 135 of the tube, while a layer of mica 138 surroundssaid cylinder. The coil 139 is disposed on the mlcalayer and 'is in turn surrounded by'heat-insulation 140. The coil 139 correatures.

sponds to the coil 113 of 2, and is connected in circuit through conductors 141. The narrow portion 136 ,of the tube is surrounded by a glass tube 142 which is substantially filled with mercury. \Vhere the tube 142 rests on the larger portion 135 20 of the first tube, an insulator 143 is inserted between the tube portions 136 and 142 so that the mercury'in the member 135 will not influence that within the tube 142. An extension 144 is provided at the upper end of the tube 136 to prevent bursting in case of overheating. A conductor 145 is connected with the metallic cylinder 137, and a second conductor 146 is connected to the mercury in the tube 142.

When current fiows through the heating coil 139, the mercury in the portion 135 expands and rises in-the narrow tube 136. The mercury in the member 135 and the metal cylinder 137 constitute thelayers of conducting elements of a fixed condenser which is connected in series with a variable condenser, one element of which is the mercury column in the tube 136, and anotherdis the mercury column in the tube 142. The capacity of the. variable condenser varies with the level of the mercury in the tube 136. This form of regulator comprises a combination of a fixed and a variable. condenser which are connected in series, and the capacity of I the variable condenser is varied. in substantially 'the' same manner as that of the condenser 114 of Fig. It will be, apparent that this regulator is particularly suitable for temperatures considerably greater than ambient temper- Fig. 4 illustratesanother form of regulating device wherein a heating coil 148. within a glass vessel 149 filled with xylol -or another-liquid having a high ten'iperature co-eflicient of expansion, is adapted to be (onnected in circuit by means of the con ductors 147. A tube 150 connects the upper end of the vessel with a globe 151, the upper and greater portion ofwhich is occupied by the xylol or othe'r'li'quid, .while its lower portion contains mercury supplied through a tube 152 connecting said globe 151 with a second globe 153, the latter having an upwardly extended tube providedwith an connected with the conductors 147 enlarged portion 155 at its top. Said glass tub e 154 is coated with a metal layer 156 which is connected with a conductor 157. A

conductor 158 is connected with the body of mercury in the tube 152.

According to the last described construction, when current flows through the heating coil 148, the xylol or other fluid expands and forces the mercury up ,in the tube 154, so that the capacity of the condenser formed by the mercury column in the tube 154 and the metal layer 156' is varied.

Preferably, the vessel 149 is arranged in a casing 160 filled with heat-insulating material 159. The rate of the capacity variation may be determined by varying the heating conditions and the'heat insulation. The space above the mercury in the extention 155 is evacuated or filled with inert gas. 1

To short-circuit the heating coil 148 in case of excessive heating, two plates 161 may be arranged in the extension 155 and by conductors 162. v

To provide the desired capacity, said device requires heating to temperatures in excess of the normal temperaturesof the room in which the device is placed, i. e., in this device, like that of Fig. 3, temperatures considerably greater than ambient temperatures are preferably employed.

Fig. 5 shows. a form of regulating device operated bythe thermal expansion of a solid Heat insulating material 167 is employed around theoutside of the coil 164. A block 168 of fibre or the like, is secured to the top of the rod 165 and a condenser plate 169 is secured to said block. Said plate 169 011- poses another plate 170 carried by a fibre supporting plate 171 which is suspended by springs 172 from a metal frame or container 173. Said frame or container which is rectangular in cross-section, supports the core 165 on its lower portion and is not thermally insulated. Thumb-nuts 174 are provided for adjusting and centering the condenser plate 170. When the core 165 expands, the distance between the condenser plates is reduced and the capacity of the condenser is increased. i

As the core 165 is thermally insulated while the frame or container 17 3 is not, the

temperature difference between said frame the advantage thatthe effect of fluctuations in the ambient air temperatures. is eliminated. r I i k I duplex armature lever 201.

' flows through the coil.

For installations where temperature fluctuations may be disregarded, the regulator may be modified as shown in Fig. 6, wherein are conductors supply ng current to "a.

" heating coil 176 surrounded by insulating material 177. An expansible core 178 for the heating coil carries an insulated condenser plate 180 adapted to co-operate with a fixed condenser plate 181 secured to a base 15 plate 179 to which the opposite end ofthe core 178 is also secured. A variable self-inductance may be used insteadof a condenser and such a device is shown in Fig. 7. The conductors 182-supply current to a heating coil 183 disposed on a core 185 from which it is insulated by a layer 184 of mica. Thermal insulating material 186 is provided for the coil' 183. A

ring 187 is secured to the upper end of the core and co-operates with an inductance coil 188 on acore 189 shown co-axial with.

the core 185. The core 189 is supported on a frame or container 190 carrying binding posts 191 connectedto theends of the in- 30 ductance coil 188. When the core 185 expands, the distance of the ring187 from the coil 188 is reduced, thereby varying the inductance of the latter..

A mechanical regulating device is illus- 35 trated diagrammatically in Fig. 8. This view is a continuation or modification of that shown in Fig. 1, and the tube 192 of an amplifier corresponds to the tube 238 of Fig.

1, or to the tubes 111, 112 of Fig. 2. In 40 this instance, the tube 192 is the last stage of an amplifier system. A magnet coil 193 is connected with thetube 192, andreplaces the measuring instrument 2.39 of Fig. 1 or the heating coil 113 of Fig. 2. The armature 194 is controlled by said coil and by a return spring 195 secured to the former. When full current traverses the coil 193, said armature isattracted and connects a magnet coil 196 to a battery 200 by making the contact at 197, while if a Weak or no current traverses the coil 193, the spring 195 will move the same to close a circuit through the contact 198 and connect the battery to a magnet coil 199. 1 The coils'196 and 199 control a For intermediate values of current, the attraction of vthe coil 193 and the force of the spring 195 are balanced and both contacts 197 and 198 are open.

Fig. 9 illustrates f our signaling stations embodying the device shown in Fig. 8. Four sets of magnet coils 196 and 199 are provided, each set acting on an armature 201 fulcrumed at 221 and con- 5 nected with vertical shafts 203. A shaft 208 a regulating device for .is shown adapted to rotate in synchronism with a' distributor which will be described hereinafter. -A friction wheel 204-is secured on the lower end of each shaft 203' adapted to co-operate with friction plates 209 and 210 'on the shaft 208. The end portion 205 of each shaft 203 is normally disposed between a pair ofribs 206 and 207 on said shaft having opposed gaps 219 and 220. While the said end portions of the shafts 203 he between the ribs206 and 207, the armatures v '201 are rendered incapable of tilting said shafts by means of brackets 202, and the friction wheels 204 will the plates 209 and 210. However, when said ends lie intermediate the opposed gaps 219, 220 of said ribs, the magnet coils 196 or 199, as the case may be, are operative to tilt their armatures 201 one way or the other, causing the wheels 204 toengage one of the plates be understood that the plates '214 will recede' from, or move toward the plates 215 depend-.

ing upon which of the plates 209 and 210 the wheels 204 are moved into frictional contact.

The opposed gaps or aligned openings 219, I

220 in the guide members or ribs 206 and 207 readily permit the lower'ends of the shafts 203 to movetowai'ds the outside of the latter and bring the wheels 204 in frictional contact with one or the other of the discs 209 and 210 to impart rotation to the. shafts 212 of the condensers in the manner rotated syndescribed. The shaft 208 is. chronou'sly with the distributor 308 of Fig.

16 as'will be described hereinafter.

In this way the condenser plate 214 is made to approach the stationary condenser plate 215 when the shaft 208 is rotated in one direction and ,to recede therefrom when the shaft is rotated I opposite direction. The gaps or ope'nin'gs'219 and 220 in the guides or ribs 206 and 207 permit the shaft 203 to swing .from'oneoperative position 'to the other when the distributor lever 308 of. Fig; 16 makes a complete reyolution, during which'the extended gaudef'end 205 of the lever 203 will lie intermediate said gaps only when said lever arrives. at the beginning of the contact period for the associated regulating device of the system. Swinging movement of the lever 203 is-thenljcontrolled by the corresponding magnet 199 or 196, and the friction wheel 204 thereon isheld friction-.

ally against the. disc 209 or 210 for a 'combe held away from plete revolution of the shaft 208 and said lever 308.

In this way the capacity of the condenser is automatically increased, reduced or kept constant according to the intensity of the plate current of the tube 192 of Fig. 8.

In Fig. 10, the condenser plates are slightly modified, the fixed plate 222 (corresponding with the plate 215 of Fig. 9) being a hollow cylinder, and the movable cylinder 223 (corresponding with the movable plate 214 of Fig. 9) being disposed inside the member 222. This form of condenser may be used in connection with the regulator shown in Fig. 9.

In conjunction with the above described apparatus, automatic fire-alarm devices may be employed, the same being directly connected with the control conductor. These fire-alarm devices are based particularly upon the speed of temperature rise caused by a fire. If the temperature increase occurs slowly, as in the normal increase of temperature in a room due to ordinary causes, no signal will be given in consequence of the operation of the frequency regulator hereinbefore described. On the other hand, a signal will be given in thecase of a rapid temperature rise, even if it is relatively small. The apparatus is thus based upon the utilization of the variations of the condenser capacities under the action of heat.

Fig. 11 shows a simple device, which, ho wever, becomes operative only at sufliciently high temperature. In this case the antenna consists of two conductors 264 and 265 connected by easily fusible metal 266. The metal will fuse when the temperature rises sufliciently, so that the two parts of the antenna 264 and 265ywill then be disconnected.

Fig. 12 shows a similar device in which overlapping ends of parts of the antenna 267 and 268 are separated by an easily fusible dielectric 269. hen said dielectric fuses upon sufficient temperature rise, an increase in the capacity of theantenna will occur owing to the resultant contact of its ends, the parts thereof thus forming, in effect a condenser, or direct contact may be made after the material 269 fuses. The device shown is simple and operates only at temperatures above a predetermined value.

- In the embodiment illustrated by Fig. 13, the condenser comprises opposed plates 270 and 27 2 separated byair, the plate 270 being fixed upon a'baseplate 271 and the plate 272 being secured to the strips 274 and 275 at which the capacity of the condenser formed by the plates 270 and 272 will be varied when perature. If the temperature rises slowly,

a compensation is effected by a regulating device hereinbefore described, and the signaling apparatus will not then be operated.

Fig. 14 illustrates a thermometer device for giving a signal in case of fire or the like. In this case, a glass tube 27 9 connects with the glass vessel 278 containing mercury and provided with a metal shell or coating 282. The tube 279 is encompassed by another tube 280 of greater diameter which likewise con tains mercury and is provided with an outer metal shell or coating 281. In the lower portion of the tube 280 is placed an insulating substance 283. A conductor 284 is connected to the shell coating 282 and a conductor 285 is connected to the mercury in the tube 280, The conductors 284 and 285 may be parts of the antennae of an installation embodying the invention. The device operates in substantially the same manner as described with reference to Fig. 3, the only difference being that the heating coil is omitted, the heating in this instance being effected by the ambient temperature.

A modification of the above described device is illustrated in ,Fig. 15. In this instance a glass tube 286 is shown containing a small amount of a slightly volatile electrolyte 287, the space 288 thereabove being occupied by air. A tube 289 extends downwardly through a stopper in the neck of the bulb with its lower end immersed in the electrolyte. IA part of said tube exteriorly of the bulbis encompassed by a metal coating 290 to which is connected a conductor 291 which may be part of the antenna of an alarm installation. The outer end of the tube is bent downwardly as indicated. The bottom of the glass bulb is provided with a metallic cup-shield or coating 292 to which is connected a conductor 293. When the air within the enclosed space 288 is expanded under heat, the electrolyte 287 will be forced to rise in the tube 289 and bring about a variation of capacity between the condenser elements 290 and 292. The sensitiveness of this device may be varied by {inclining the tube 289 at different degrees to\a horizontal plane, because the electrolyte to be raised by the same degree of heat will ascend the tube more easily if the latter is inclined.

It will be readily appreciated that various other devices for eflecting fire-alarms" may be connected. with the described signaling apparatus without departing from the scope of the invention.

Fig. 16 diagrammatically illustrates a complete system having three local stations of differing periods. In this illustration,

the three local stations are represented in connection with --a single central station,

The three local stations comprise antennae or control'conductors 300, 301 and 302 respectively with coupling coils 303, 304, 305 associated therewith. Said coupling coils are shown connected together in series and with the couplingcoil .306 of the central erence to the signaling systems. Said distributor comprises three series of contact strips over or in relation to which a continuously rotating contact-arm 308 is moved. The intermediate strip' 309'is unbroken, but the inner and outer contact strips are subdivided into three sectors 318, 319, 320 and 321, 322, 323 res ectively, corresponding with the number 0 local stations.

The plate of the oscillator tube 294 is I connected with three parallel circuits comprising a condenser 312, 313, 314, a noninductive resistance 315, 316,317 and a variable condenser 329, 330, 331 respectively.

Each resistance is connected to one of the three outer sectors 321, 322, 323 of the distributor. The inner sectors 318, 319,- 320 are connected to a contact 327 through heating coils 324, 325,326, respectively, of the variable condensers 329, 330, 331. These condensers are of the form shown in Figs; 3 to 7. However, said condensers may be con 'structed to operate mechanically as shown in'Figs. 8, 9 and 10.

The rotating arm 308 connects the condensers 312, 313, 314, the, resistances 315,

316,- 317 and the-varible condensers 329,

330 331 successively. in parallel with the sel -inductanoes 296,297. The variable con densers 329,- 330,331 have such value as to 've resonance with the respective antennae.

otation of the distributor alternately tunes the central station oscillator to waves corresponding approximately to the waves of the local stations 300, 301, 302, and if resonance is establishedfthe energy of the oscillator is "transmitted to the antennae. This alters the current in the grid circuit of the tube 294 and causes a -variation-of the grid potential and of a grid-leak resistance 332;- Such variation of potential is amplified by the amplifier system 333, the current of the amplifier system flowing through the winding of the electromagnetic relay 334. As

theintensity of the amplifier current decreases, the variation of grid otential 1ncreases that is, the greater and the oscillator. I

The relay 334 attracts an armature 335 and said armature alternately closes one of the contacts 338, 339 between which is connected a non-inductive resistance 340. A battery 341 and a second electromagnetic relay 342 are in'the circuit formed by the ecomes the difference in periodicity between the antennae 1 to which a return spring 336 is attached,

portion 337 of the armature and the two contacts 338, 339. The latter relay attracts an armature 343, the portion 344 of which is connected with a return spring 345. The

port-ion 344 ofthearinature 343 may engage 4 one of the contacts 327 and 328, A con ductor 346 connects the armature 343 to the heating current source 310 of the oscillator and amplifier cathodes. A non-inductive resistance 347 is connected between the 1 source 310 and the contact 328. A relay 348' and an alarm 349 are also connected between one terminal of the source 310 and the contact 328 inparallel with the-resistance 347 the resistance serving to diminish the effect of the closing of the. contact 328 upon the voltage of the source 310. and thereby upon the otherfdevices connected to said source.

When the relay 348 is energized, the armature 350 thereof closes the circuit of the alarm 352 through the contact 35l.

When a person or foreignobject approaches one of the antennae, the wave length When a circuit isclosed through the cons tact 339, the relay 342 will be traversed by maximum current. The relay 342 will be l de-energized when the circuit is open and,

will be traversed by currentw'eakened' by the'resistance 340 when the circuit is closed through the contact 338. The armature of the rel-ay 342 will assume corresponding attracted, retracted or intermediate positions, In the attracted position, the contact 328 is closed and the .relay 348 and the two ala1'ms349 and 352 become operative. 'In

,the retracted position, the relay 348 is not energized and contact 327 is closed. In the intermediate position, the current through the relay 342 is balancedby Y the spring 345,

and no contactlis made bytheai'mature.

In this latter case, the tuning-between the antenna and the oscillator 294 is such that onlya smallcurrent flows. through the relay .334. When,the current increases, the arma- "ture 335 assumes an intermediate position and the armature 343 of .the relay 342 closes a circuit through the contact 327. In consequence, the heating coils 324, 325 326 are alternately heated'by alternating Current from the source 310. This varies the regulator capacities as described abovev in connection with Figs. 3-7, and the tuning between the antenna and the oscillator 294 340, thereby opening the circuits of the heating coil- s 324, 325 and 326 at the contact 327.

In this manner, the normal fluctuations of antenna capacity are compensated to prevent the undesired operation of the alarm. The compensation for each antenna is effected independently by means of the distributor 30,7.

In case of sufficiently high resonance between an antenna and'the central station-oscillator, for instance in consequence of the approach of a body towards the antenna, the plate current of the amplifier 333 flowing through the relay 334 increases and the relay closes the circuit of relay 342 through the contact 339, whereupon the relay 342 energizes the alarms 349 and 352. The alarm 349 stops ringing when the regulator has detuned'the circuits as described above. However, the alarin352 remains in operation until the armature 350 of the relay 348 is reset by hand..' The alarm 349 thus indicates the cause of the alarm temporarily, and the alarm 352' will continue to operate until the watchman is attracted by the signal and stops it. It will-be understood that if desired, only one ofthe two alarms need be used.

If the variation'of the capacity of an antenna takes place so slowly that no signal should be given, for instance on account of atmospheric changes, the-amplifier current changes so gradually that the regulator is operative to compensate for the, variation of the capacity or the platecurrent respectively, and the signaling devices are not then operated. If, on the other hand, the capacity variationlof the antenna takes place so quickly that a signaljshould be given, for

instance in consequence of theapproach of a burglar toward one of the antenna disposed along a wall, around a window or door or otherwise, the amplifiercurrent will use rapidly and the alarm deviceswill be operated since the regulator will not then beable to compensate for the capacity variation.

it is necessary only to interchange the contacts 339 and 338 ofthe relay 334.

If it is desired to provide an arrangement such that upon approach of a 'body to the antenna, resonance effect between the anten- By providing a fourth contact strip on the distributor, annunciators may also be operated, which will show at a glance at what particular place the disturbance has taken place.

It is obvious that the systems of connections described and illustrated are but few of the arrangements possible for carrying out my invention. 'will be able to modify the different systems according to various requirements and con- Thoseskillecl in the art ditions without departing from the spirit and scope of the invention, and the applicability of tlie'invention to Various purposes as also the manner of arranging and concealin'g the antenna leads will be readily appreciated. I

Therefore, it is not intended that the invention shall be limited by the appended claims to the specific constructions, arrangements and combinations asherein described and disclosed in the drawings.

I claim: I

1. A signaling apparatus comprising a circuit including a control conductor, an oscil lating system connected with said circuit to induce oscillations therein, a regulator compensating for variations in frequencies occurring from normal influences upon the circuit, and indicating means responsive only to uncompensated rates of variation of the resonant frequency of said circuit occasioned by abnormal influences thereon.

2. A signaling apparatus comprising a cii cuit including a control conductor, an oscillating system connected, with said circuit to induce oscillations therein, a regulator embodying a thermal element traversed by current from said oscillating system for compensating for variations in frequencies 00- curring from normal influences upon the circuit, and indicating means responsive only to uncompensated rates of variation of the resonant frequency of said circuit occasioned by abnormal influences thereon.

3. A signaling apparatus comprising a cirtermined rate for causing said circuit to be compensating means operating at a prede-' maintained at a constant frequency after each change dependent upon the variation caused in the system, and indicating means.

operated by a change-in the system causing the frequency thereof to vary at an abnormal h rate.

"4. A signaling apparatusi comprising a circuit including a control conductor, an oscillating system connected with said circuit to induce oscillationsthereiin'ia regulator.

compensating for variations in frequencies occurring from normal influences upon the circuit, and indicating means responsive only said circuit occurring at a rate above a precillating system connected with" said circuit} determined value.-

5. A 'signa l1ng apparatus comprising a c rcuit including a control conductor, an os-j the thermal expansion of said liquid and means for transmitting the Variations of capacity to said system to compensate for I normal variations in the resonant frequency fof said circuit. 7

10. A- signaling apparatus Comprising a to induce oscillations therein," indicating plurality of local stations, each having a cirmeans connected to said circuit, a heating coil in said system, and means including said heating coil for varying "the electrical'coiistants of the scillating system to compensate for variations of the resonant frequency of said circuit where the rate is different from the rate to be indicated. 1

6. A signaling apparatus comprising a circuit-including'a control conductor, an oscillating system connected with said circuit to induce oscillations therein, indicating means connected to said circuit, a heating coil connected to saidsysteni, and means including said heating coil" for varying the capacity of a portion of the oscillating system to compensate for normal variations in.

the resonant frequency of said circuit.

'7. A signaling apparatus comprising a circuit including a control conductor, an oscillating system connected with said circuit to induce oscillations therein, indicating means associated with said circuit, a heating coil. connected to said system so that its current varies in accordance .with changes in frequency of the system, a condenser, and means including an expansible liquid as one element thereof associated with the heating coil for'varying the capacity of a portion of the oscillating system to compensate for norfma-l variations in the resonant frequency of said circuit.

8. Asignaling. apparatus comprising a circuitincluding a control conductor, an oscillating sys tem connected with said circuit to induce oscillations therein, indicating means associated with said circuit, a heating -coil connected tosaid system so that its curbodying a 'vessel containing a liquid of high,

thermal, expansion coeflicient associated said heating coil and means including said condenser-for. varving the capacity of a portion .of the oscillating system to compensate for normal .varia'tionsin theresonant,

qu y Of Said circuit. 7 l I 9, A signaling apparatus comprising a c1r cuit. includinga'control conductor. an oscillating system connected with said circuit to induce oscillations therein, a heating coil connected to said. system so that its current va ries in accordance with changes in frequency of tlie system, 'avesse'l containinga l quid of high 'thei' l ijal expansion coefficient in heatcoiiducingf relation to said coil. a shunt '1 around saidheating' coilclosed bLFZtld liquid at a high temperature, a condenser connected 3' with said vessel to be varied incapacity by cuit including a control conductor, said circuits having different resonant frequencies, a central station to which all of said local stations are connected, an oscillator system and a signal at said central station, means compensating for variations of frequency occurring below a predetermined rate so that the detecting means will not be affected thereby, and signal indicating means operable by said detecting means.

12 A signaling apparatus comprising a circuit including a conductor extending relatively to an area to be protected, means including an oscillator for detecting abnormal rates of variation in the resonant frequency of said circuit, means including a thermalresponsive element connected to the oscillator for compensating for variations of frequency occurring below a predetermined rate so that the detecting means will not. be affected thereby, and a signal operable by said detecting means.

13. A signaling apparatus vcomprising a circuit including a conductor extending relatively to an area to be protected, means including an electrical oscillator for detecting abnormal rates of variation in the resonant frequency of said circuit. means for compensating for variations of frequency occurring below a predetermined rateso that the detecting means will-not be affected thereby, said compensating means eiiribodying a retarded controlling device for varying the frequency of oscillation of said oscillator,

rate to counteract the effects of natural disturbances and operating a signal when the variation in frequency occurs above said predetermined rate.

15.. The herein described method of operatnant frequency of-said circuit, means for' too ' of said vibrations upon the approach of an object thereto, to produce a signal upon such change and restoring the system to normal at a definite rate whereby the signal will be operated only upon disturbances occurring above a predetermined rate.

. 16. The method of operating a continuously operative signaling system embodying an oscillator which is subject to relatively slow natural disturbances characterized by gradually restoring said oscillator to its normal frequency upon any departure of the same from the normal frequency whereby the signaling system is not affected by such natural disturbances and operating a signal upon a predetermined rapid deviation from the normal frequency.

17. The method of operating a signal in a signaling system embodying an oscillator characterized by generating oscillations in the system, continuously and gradually compensating the system for changes in the frequency of the oscillations resulting from inherent or natural causes and actuating a signal upon a sudden relatively large change in the frequency of the oscillations.

18. A continuously operative alarm system comprising an alarm, a control conductor, an electrical oscillator, means including the conductor for controlling the oscillatory current from the oscillator, means for maintaining the oscillator at normal frequency despite the effects of atmospheric disturbances and the like and means for operating the alarm upon an abnormal change in frequency of the oscillator.

19. A signaling apparatus comprising a plurality of local stations, each having a circuit including a control conductor, said circuits having different resonant frequencies, a central station to which all of said local stations are connected, an oscillating system and a signal at the central station, means for consecutively tuning said oscillating system to the normal frequency of each of the tuned circuits at thelocal stations and means for operating said signal upon a relatively large change in the resonant frequency of any of the tuned circuits at the local stations.

20. The method of operating a continuously operative signaling system embodying an oscillator which is subject to relatively. slow natural disturbances characterized by gradually restoring said oscillator to its normal frequency upon any departure of the same from the normal frequency whereby the signaling system is not affected by such natural disturbances and-operating a signal upon a relatively rapid change of frequency of the oscillator.

-21. The method of operating a signal in a signaling system embodying an oscillator characterized by generating oscillations in the system, continuously and gradually compensating the system for changes in the frequency of the oscillations resulting from inherent or natural causes and actuating a signal upon a sudden relatively large change in the frequency of the oscillations.

22. A continuously operative alarm system comprising an alarm, a control conductor, an electrical oscillator, means including the conductor for controlling the oscillatory current from the oscillator, means for maintaining the oscillator at normal frequency despite the effects of atmospheric disturbances and the like and means for operating the alarm upon an abnormal change in frequency of the oscillator.

23. A signaling apparatus comprising a plurality of local stations, each having a circuit including a control conductor, said circuits having different resonant frequencies, a central station to which all of said local stations are connected, an oscillating system and a..signal at the central station, means for consecutively tuning said oscillatting system to the normal frequency of each of the tunedcircuits at the local stations and means for operating said signal upon a relatively large change in the resonant frequency of any of the tuned circuits at the local stations. 7

In testimony whereof, I have signed my name to this specification.

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