US2345472A - Remote control system - Google Patents

Description

Marh 28, 1944- A. N. GoLDsMrrH REMOTE CONTROL SYSTEM l Filed Oct. 20, 1939 4 Sheets-Sheet l WWK n.

March A28, 1944- A. N. GoLDsMITH ,A 2,345,472

REMQTE CONTROL SYSTEM Filed Oct. 20, 1939 4 Sheets-Sheet 2 IN TOR ALFRED N. DSM/7H E* M M ATTORNEY T March 28, 1944.

' REMOTE CONTROL SYSTEM Filed oct. 2Q, 19:59 4 sheets-Sheet s my mh um my n v if w 97 97 ya /02 a fa/ K 00 99 701 lbs ,v INVENTOR ALFRED N. GOLDSM/TH ATToRNEY A. N. GoLDsMlTli 2,345,4724

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March 28, 1944. A, N GOLDsMn-H 2,345,472

REMOTE CONTROL SYSTEM Filed Oct. 20, 1939 4 Sheets-Sheet 4 INVENT ALFRED /v. Gow rf/l ATTORNEY Patented Mm.v 1944 REMOTE CONTROL SYSTEM Ain-ea N. Goldsmith, New York, N. Y., minor to Radio Corporation oi' America, New York, N. Y., a corporation of Delaware Application oezoberzo, 1939, serial No. 300,326 l '1 claims. (c1. 25o-2) The presentixiventionrelates broadly to remote control systems which they may be'used,

-In one particular embodiment of the invention modulated supersonic waves are used to remotely control a radio receiver.

Among the objects of the invention may be mentioned the following:

1. To enable the remote control of a radio receiver (or transmitter or other similar controllable device) within a given room without special or direct electric wiring between the control device and the controlled receiver.

2. `To permit such control with a multiplicity of selective procedures as, for example, turning the receiver on"and oll', tuning the receiver in one or both directions, and the like.

3. To obtain the above control regardless oi' the 4. To obtain such control even in the case of battery-operated receivers having no connection to electric circuits.

5. Toobtain such control alternatively with or outside electric power supply or circuit.

6. To secure such control regardless of the relative positions of the control device and the receiver in the room.

7. To secure such control without acoustic interference withpersons in the room or reproduced v music or speech.

While other objects of the invention will be apparent from a reading of the following detailed speciiication, it is apparent from the preceding that th'e aims ofthe present invention are unusually broad. f

In one method of carrying out the presentinvention use `is made of sound impulses, waves or trains radiated from the control device and received by the receiver which is at all times activated to the extent necessary to respond to such sound impulses. In the present specification the term impulses is intended to include waves, trains or other formed groups or sequences of groups of sound whether audible or inaudible.

The invention may be best understood by referring to the accompanying drawings and the iescription of the arrangements disclosed there n.

In said drawings,

Fig. 1 illustrates in schematic form, va diagram -nature of the power circuits feeding the receiver.

\ without connection of the control device to any i which will be referred to in describing the general aspects of the invention;

Fig. 2 illustrates one form of an electrically operated modulated supersonic oscillator;

Fig. 3 illustrates in schematic form an arrangement for diiusing the waves emitted by a device such as disclosed in Fig. 2;

Fig. 4 illustrates an oscillator using a similar drive to that illustrated in Fig. 2 but employing a wide angle radiator;

Fig. 5 is a representation of ya device for producing control waves by mechanical excitation;

Fig; 6A illustrates another form of a mechanically excited oscillator;

Fig. 6B is a sectional view of the oscillator shown in Fig. 6A;

Fig. 7 is adiagrammatic showing of a device using a siren method oi modulation; and.`

Fig. 8 vis al diagrammatic illustration of an ar-` rangement which'may be used to receive the 00ntrol waves.

In the system illustrated in Fig. 1, Als an OS- cillator which may be supplied with power either from an A. C. or D. C. power supply available from a power outlet in the room in which it is f located or if desired power may be supplied from a self-contained battery or if desired the power ferred. The oscillator may be of the tube type,

ofthe crystal type, of the magnetostrictive type or of the mechanical vibrator type.

In order to enable appropriate control signals to be sent there is providedthemodulating.control-B which controls the 'oscillator A. Physically, the control may be by knobs, buttons, and the like. The mode of control may be either by amplitude modulation or frequency modulation or.

f a combination of these. The control may involve a setting for on-ofi oi' the receiver and a'reversible-motor tuning control or else a continuous-rotation tuning motor control,.or the equivalent of these, together with such added controls las may seem desirable (example, in the case of the sonic radiator C. This may be .any type of direction of radiation controllable (f or example l toward the receiving set).

matic frequency control or not, butshould preferably have this feature.v The drive motor I will In the drawing, D indicates the radiated sonic Y waves between the control device and the receiver. Infra-sonic or, ultra-sonic waves are used because these do not interfere with the persons in the room and further because these frequencies fall outside of the range of frequencies acoustically radiated by the receiver and can therefore be selectively received at the receiver during the time that the receiver is in operation,

lthus enabling changes in its operation to be performed without interference from the sound which is radiated by the receiver itself.

In the right hand portion of Fig. 1 is shown in a general manner a suitable arrangement at the receiving set for eilectuating the control. The control signals are received by a sonic receiver or detector E which may be any type of sound receiving or detecting device suitable for the frequency range in question and of adequate sensitivity. lThus it may be a telephone transmitter of the electro-dynamic, electro-static. microphonic, or piezo-electric or similar type. It may be the loudspeaker of the receiving set provided such loudspeaker is suillciently responsive to the control frequencies. It may be the highfrequency unit (tweeter") of the receiving loudspeaker provided this is sensitive to the frequencies used. Or it may be the low frequency unit of .the receiver loudspeaker. It may be made directional or non-directional It may be connected to a power supply for energizing or amplifying the response. or it may be not so connected.

It may be sharply resonant or broadly resonant to the incoming control frequencies. If it is made sharply resonant, ,it will probably be more sensitive but will build up in` response more slowly. It can be changed from sharp to broad resonance or vice versa by the incoming signals thus altering its sensitivity.

The output of thesonic detector E passes through a filter F the function of which is to permit only control frequencies to reach the controlling mechanism of the receiver. The lter.`

will be of the low-pass type for infra-sonic control signals or of the high-pass type for ultrasonic control signals. The ilter may be either electrical or mechanical.

The filter output passes into the amplier orv control G which may be supplied with power locally as indicated in the drawings. The amplifier in question may operate by amplitude varia-v tion control or it may be primarily responsive to a frequency or frequencies through resonant response.

The output of the amplier G acts upon and energizes the remaining portions of the receiver control. Thus the output of the amplifier may be used to control the on-oil switch H with an intervening relay if required. It may also control with a relay as required the tuning motor I.

The receiver J contains the power unit K which is controlled by the on-oii switch H. The power supply of devices E andG, if required, is always on. Accordingly any tubes in E and G, if used, are of such types'as to require minimum power to'energlze them and to give a maximum change in the controlled energy for minimum received excitation.

The receiver J may bev provided with autopacities.

have a starter relay as required and as mentioned above. It may be made reversible or non- A reversible in its control.

The drive motor I controls the tuning device L in the receiver; This tuning device may be a group of variable capacities, a group of yvariable inductances, a combination of these, and

wave-range switching means as required. The tuning may therefore be eitherwone involving electro-mechanical devices (for example,a vari- `able condenser bank) or the tuning may be of the straight electronic type whereby inductances or capacities or a combination of these are reflected through a tube into a tuned circuit or modied in amount by a tube or tubes suitably connected to such inductances and ca- Or combination electro-mechanical and electronic tuning may be used.

For generating supersonic oscillations which are modulated at either sub-audible or superaudible frequencies various arrangements may be used. Such oscillators may be either electri` cally or mechanically excited or a combination of these. While electrically operated remote control stations require a source of electric power they have the advantage that there is no demand for power upon the person handling the remote control. One such form of supersonic modulated oscillator is illustrated in Fig. 2. It will be understood however thatl the electromagnetic form of oscillator having a small conical radiator of air Waves illustrated in Fig. 2 ispurely The form shown in Fig.l2 is essentiallyl an eleco trically modulated supersonic air wave radiator. The two cones I5 and I1 are joined by a thin cylindrical member 2i on which is woundl the motor coil I5, the'terminals of which are I3 and I4. The coil I5 surrounds the end portion I8 of the core II which may be either a permanent magnet of maximum strength or which may be wound with the coil 'I fed by direct current applied across terminals 6 and 8 and therefore magnetic. If an electric current of supersonic frequency, e. g., 20 kilocycles, is fed. into the coil I5 through. flexible conductors from the terminals I3, I4, the two cones I6 and I1 `will be-caused to vibrate simultaneously in the directions indicated by the arrows I9, 20. It is not believed necessary here to show anyfmeans for flexibly supporting the cones in question since such means are well known in the loudspeaker art. It will be noticed that the field from the core II is for example vertically up through the upper half of coil i5 and vertically downward through the lower half ci' coil I5, assuming north polarity of the core within the coil and south polarity of the adjacent f ends of the yokes 9, I0. The cones I6 and il' will then be a supersonic air wave radiator.

Coils 3 and 5 may be wound as shown on the yoke and a sub-audible current, e. g., of 30 cycles and of suitable amplitude may be'passed through coils 3 and 5 from terminals I and 2. The magnetic flux through coil I 5 resulting fron the curcoils l and l in place o! the 30 cycle lsub-audible frequency current there would be littlel air wave radiation from .these small cones aty so low a frequency and, of course, no audible sound. The

current in coils l and l does however change the magnetic condition of the yoke l, Il and the.

Thus, it brings these magnetic elements tion in the-other 4half of the cycle of current As a result the twentythrough coils I and 5. kilocycle field of coil I5 interacts with a second field of frequency of 30 cycles and'accordingly the amplitude oi' the oscillations of cones It and l1 at 20 kilocycles is modulated by the 30 cycle current in coils 3 and i.

In the operation of a device such as that shown in Fig. 2, it willv be appreciated that to selectively control the. operation o! a plurality of devices which are located at a remote point, it is only necessary to employ dlierent modulating frequencies in a selective manner, that is, assigning a certain action to be performed at the remote point to each modulating frequency or combination of modulating frequencies and modulating the transmitted energy by the particular modulating frequency or frequencies corresponding to the action desired to be performed at the remote point. At the remote point the transmitted control energy is received and demodulated. The products of demodulation are then suitably segregated and used for control'purposes such as to operate relays and the like.

It may be mentioned parenthetically that a system of supersonic and inaudible telephony by air waves may be based on this principle by feeding the telephone currents into terminals I and 2. However, in this case the supersonic oscillations must be made intense and the straight line portion of the magnetization curve of the yoke and core must be used to avoid non-linear modulation and consequent rectification and audible speech radiation.

It is appreciated that normally supersonic air wave radiation has a highly directional nature.

Figs. 3 and 4 of the drawings illustrate methods of modifying this highly directional nature. One

method of modifying the highly directional radiconnecting element 2| oi' Fig. 3 corresponds to' the connecting element 2| of Fig. 2. It is to be understood, though not illustrated, that in Fig. 3

the element 2| carries a motor coil such as,coil I 5 of Fig. 2. Reilectors 38 and 31 which are shown as frustra of cones with their smaller openings in juxtaposition, are placed surrounding the cones It and I1 respectively. The arrows Il and 4I have been drawnin Filz.` 3 in represent the direct air wave radiation resulting from the motion ofthe cones. Supersonic waves renected from the frustra 36 and 31 and'diversing outward are shown by the arrows 42, Il, u and II. It is recognized that interference phenomena between radiation from one or two cones vand reflective radiation may occur but the nnite magnitude of the oscillators and reflector as well as thereceiv- In the form of multi-directional or wide angle supersonic radiator illustrated in Fig. 4, the radiator is shown as a cylindrical surface," which is fastened at one end 02 and which is attached to the motor element 5I arranged tov oscillate at supersonic frequency. A spring restoring element 51 is shown as fastened at Il. If the radiator il is made f appropriately small dimensions and suitable mass and elasticity it will `oscillate in the directions shown by the arrows Il and 6l l and will radiate considerable amounts of supersonic energy in a wide angle of directions. The

coils` 3 and 5, 1 and l5 of Fig. 3 correspond to the coils in Fig. 2 bearing the same numbers and the yokes l and Ill and the core Il oi' Fig. 4 oorl'o, respond to the same elements of Fig. 2.

As previously pointed out it is sometimes desirable to avoid the use ofelectric power'at the remote point. Under these circumstances it becomes necessary to have available a powerful source of supersonic air waves produced by mechanical excitation. These mechanically generated supersonic waves may also be modulated at a sub-audible, audible or super-audible'frequency. One form ofsuch oscillator is shown schematically in Fig. wherein Il is a vibrator of any suitable type which is capable of producing supersonic vibrations when violently struck by means of a hammer 12 which is capable of striking element Il when swung about its Vpivot point 15. The hammer 12 is operated by means of a key or lever 11 against the .force oi a spring 1l`which is attached between a lugv on the `key and casing 1l. Element Il is mounted lon a comparatively thin metall sheet 1l which is held atv the preceding it is seen that the supersonic oscillator n is oarrled on Ian audio oscillator n and l accordingly the supersonic waves passing outward through the holesor slots l1 in box or enclosure 18 which may be composed of wood, will b'e to'some extent modulated by the vibration frequency of 1i. As previously inferred the vibration frequency of 1| may be `sub-audible, audible or super-audible. The arrangement shown in Fig. 5 constitutes an association of a supersonic oscillator, a lower frequency oscillator, and a common impulse excitation means for both.

In the operation` of the device shown in Fig.

5, depression of key I1 causes counter-clockwise rotation of hammer 12 about its pivot point 1i against the force'of spring 1I. continues until the continued downward movement of 'key 'I1 causes arm to slip oil of shoulder i1! thereby releasing-al1 oil the mechanical energy stored up by .spring 14 which causes the hammer 12 to strike vibrator Il viooo lently. sp1-lng u tends to bl-l book the llammer to its normal released position. When key 11 is released it returns to its normal released position through the action of spring 18. Arm Il is pivoted on the key 11 and is held resiliento5 ly against a suitable stop by the action of a spring 1l. vThis is for the purpose of permitting arm I8 to ride over shoulder 13 on the^return movement of key 11.

Another form of possible moo'llanloal oscillator' for both supersonic and lowel frequency oscillation with modulation of the supersonic frequency is shown schematically in Figs. 6A and 6B. Referring-to Fig. 6A it will be seen that there is provided a pair oftorsional oscillators 0i and Il. These oscillators are hollow or solid This movement 'flat portions |04 of. vanes arrangement the diaphragm `any suitable means not here ing supersonic waves. the generated supersonic waves in the arrangecylinders. y The oscillator. 9| is preferably .rigidly fastenedat its bottom surface to a suitable mounting' ring 92 which in turn is resiliently mounted by means of spring clips 93, 93 to ,a base plate 94. The arrangement is such that oscillator 9| canbe twisted by impact so as to cause it to oscillatein the directions indicated 9| is provided with small vanes 99 while Athe,

oscillator 98 is provided with small vanes. |00. These small vanes become air wave radiators. The whole structure is enclosed within 4a suityable housing 91 which is provided with' a plurality of .slots or openings |0.| in registration with the vanes 99. 'Ihe oscillator98 is provided` with an impact block |02 against which hammer 'I2 operates. Hammer 12 is operated by depression of key 11 similarly in every way to the arrangement described in connection with Fig. 5.

As indicated 4in Fig. 6B it is possible to cause the supersonic radiation from oscillator :98 to travel" outward through openings in the casing 91 which may be blocked or opened by the 99 thus modulating such supersonic frequencies by the frequency of oscillator 9|.

Still another method of modulating the supersonic vibrations is schematically indicated in Fig.

7. 'lhis arrangement applies either to electrical- `ly excited or mechanically excited supersonic .waves In Fig. 7 the enclosure 3 is provided -witha series of holes or slots H2. A diaphragm H8 'carries the cylindrical element 9 which may be part of it on its outer portion in approximate registry.with the openings ||2. I f in such an ||8 is caused to vibrate through the attachment elements I9 by shown and in the Y impulses are then fed into a tuned circuit |40,

|4|, |42,4 |43 which may in turn be tuned to the modulating frequency,-e. g., 30 cycles (which modulating frequency may be audible, sub-audible or super-audible). This last named tuned circuit is in turn coupled to rectifying circuits |44,

. |45, the rectified output of which passes from 1ead&|49, Nl into the controlling relays orsimilar elements.

If a receiving element of the type shown in Fig. 5 is provided, that is, if the receiving element is responsive to both supersonic and low frequency air waves, the modifications of the circuit of Fig. 8 are believed to be obvious therefrom. In this case the doubly resonant receiving system will produce an output which can be withdrawn preferably in the form of currents of modulated supersonic frequencies or in the form of two currents one of which is supersonic in frequency and the other of which is of a lower frequency. The selection of such currents, their amplification and their rectification, together with their utilization in appropriate relay systems need not be further described herein. Y

It is thought to beobvious from. the above discussion that it is the intent of the receivers described herein to respond to modulated supersonic air waves and effectively to utilize resonant response to the supersonic frequency and also to the lower frequency of modulation in order to minimize false (indications and to give a maximum number of possi-ble indicating signals from a given group of frequencies in the remote control station.

I claim:

1. The steps in a method of remote control which comprise generating aerodynamic wave energy of a low supersonic frequency, modulating said energy of supersonic frequency with energy .of a sub-audible frequency, radiating the thus modulated energy of supersonic frequencyfas airbornetfree wave energy, receiving the said airdirections indicated by the arrows H5, lthe exit of supersonic Waves through openings I2 will be facilitated or retarded in substantial synchronism with the oscillations of ||8. Essentially this arrangement is a siren method of modulat- It may be added that ment shown in Fig. 7 may be produced in any well known manner, as, for instance, bymeans of a pneumatically-operated device. It is obvious from the above that the arrangement shown in Fig. 7 combines a pneumatically-operated supersonic oscillator and a siren or Amobile gate valve type modulator at sub-audible, audible or superaudible frequencies.

Suitable receiving means for waves transmitted` by any of the foregoing arrangements may take the same form as the radiators of said arrangements. If a supersonic oscillator 'alone is used as a receiver an arrangement such as that indicatedin Fig. 8 may be utilized. In said gure the receiving oscillator |22 carries the coil |23 in a constant magnetic field excited by coil |30 through yoke 2| and core 3|. Current of modulated supersonic frequency will flow through condoctors |24, |25 into the tuned circuit |34, |35

sonic modulated/impulses are produced. These borne free wave energy, demodulating the received energy, selecting from the demodulated energy the modulating frequency component of the received energy, and utilizing the resultant energy output for remote control purposes.

2. In a system for the remote control of an element` of a radio receiver or the like, meansv for generating Wave energy of a'low supersonic frequency, means for generating wave energy of a sub-audible frequency, means for modulating the wave energy of low supersonic frequency by the Wave energy of sub-audible frequency, means for radiating the resultant modulated supersonic frequency energy as aero-dynamic free wave energy. means located adjacent said radio receiver forvreceiving and demodulating the radiated free wave energy. means for selecting from thedemodulated energy the modulating frequency component of the received energy, and means utilizing the latter to control said element of the radio receiver or the like.

`3. In an aero-dynamic remote control system, means for generating electrical energy of a superlSonic frequency, means for generating electrical energy of a lower frequency, means for modulating the electrical energy of supersonic frequency and |36. This tuned circuit is coupled lto a recti- 'Y .fying circuit |31, |38, |39 wherein rectified superbyjthe electrical. energy of lower frequency and means for radiating the resultant modulated supersonic frequency energy as air-bornefree wave energy, said last named means comprising a magnetic circuit provided with -a gap, a surface radiator vof supersonic energy,. a coil system mounted in said gap and rigidly attached to said radiator, means adapted to connect said coil system across the supersonic frequency generating means. and means for exciting said magnetic circuit by the generated modulating frequency energy. n f' 4. In an aero-dynamic remote control system, means for generating electrical energy of a supersonic frequency, means for generating electrical energy of a lower frequency, means for modulating the electrical energy of supersonic frequency by the electrical energy of lower frequency and means for radiating the resultant modulated supersonic frequency energy as air-borne free wave energy, said last named means comprising a magnetic circuit provided with a gap, a 'surface radiator of supersonic energy, a coil system mounted in said gap and rigidly attached to said radiator, means adapted to connect said coil system to the source of supersonic frequency energy,

means for exciting said magnetic circuit by the electrical energy of the modulating frequency, direct current energizing` means electrically asso-1 ciated with said magnetic circuit whereby the latter is affected as to ux and permeability only by a constant excitation througndirect current.

5. In an aerodynamic remote control system, a source of electrical energy of a supersonic frequency, a source of electrical energy of a lower frequency, a unitary device for modulating the supersonic frequency energy by the lower frequency energy and radiating the resultant modulated supersonic frequency energy as air-borne free wave energy, said device comprising a magnetic circuit provided with a gap, a surface radiator and a coil system mounted in said gap and rigidly'attached to said radiator, means for connecting the coil system to said source of supersonic frequency energy, and means for exciting said magnetic circuit by energy derived from said source of modulating frequency.

6. In a system for the remote control of an element of aradio receiver or the like, means for generating electrical energy of a low supersonic frequency.'I means for generating electrical energy of a sub-audible frequency, means for modulating the electrical energy of .low supersonic frequency by the electrical energy of subaudible frequency. means for radiating the resultant modulated supersonic frequency energy as aerodynamic free wave energy, means located adjacent said radio receiver for receiving and demodulating the radiated free wave energy, means for selecting from the demodulated energy the modulating frequency component of the received energy, and means utilizing the latter tc control said element of the radio receiver or the like.

7. In a system for the remote control of an element of a radio receiver or the like, means for generating aerodynamic energy of a low supersonic frequency, means for modulating said energy of low supersonic frequency with energy of a sub-audible control frequency, means for radiating the resultant modulated supersonic frequency energy as air-borne free wave energy, means located adjacent said radio receiver for receiving and demodulating the radiated free wave energy, means for selecting from the demodulated energy the modulating frequency component of the received energy, and means utilizing the latter to control said element of the radio receiver or the like. q

' ALFRED N. GOLDSMITH.

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