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Publication numberUS1571405 A
Publication typeGrant
Publication dateFeb 2, 1926
Filing dateJul 31, 1919
Priority dateJul 31, 1919
Publication numberUS 1571405 A, US 1571405A, US-A-1571405, US1571405 A, US1571405A
InventorsNorton Goldsmith Alfred
Original AssigneeRca Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for wave changing in radiosignaling
US 1571405 A
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Description  (OCR text may contain errors)

Feb; 2 1926. 1,571.405

.A. N. GOLDSMITH APPARATUS FOR WAVE CHANGING IN RADIOSZGNALING iled July 31 1919 4 Sheets-Sheet 1 INVENTOR Feb. 2 ,1926. 1,571,405

AFN. GOLDSMITH Arman-us roa wAvn-mmmeme m mmsmuumo Fild' July 31 1919 4 Sheets-Sheet 2 m ENTORY Feb. 2 1926. 1,571,405


. Ygfmgmon Feb. 2 192s. 1,511,405

- A. N. GOLDSMITH APPARATUS FOR WAVE CHANGING IN RADIOSIGNALING Filed July 31 1919 4 Sheets-Sheet 4 Patented Feb. 2, 1926. I p




Application filed Jul 31,1919. Serial a. 314,470.

To all whom it may concern.

Be it known that I, ALFRED N. Gomsm'rn, a citizen of the United States, and a resident of the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Apparatus for Wave Changing in Radiosignaling, of which the following is a specification accompanied by drawings.

This invention relates to radio signaling, but more particularly to a method and apparatus for wave changing.

The primary object of the invention is to provide a readymeans of changing the inductance of the desired circuits conveniently and continuously, especially applicable for fine tuning or coarse tuning of antennae and secondary circuits, to produce simple transmitting and receiving wave changers in which the variable elements may be controlled if desired by the manipulation of a single operating handle or other controlling device, thus forming a uni-control transmitter or receiver, without multiplication of parts.

I have found that an inductance in the field of which a conducting shield forming a short circuited secondary is adapted to be moved in one direction or an0t her,-or periodically introduced and Withdrawn, forms an efficient and satisfactory means for changing wave length. The variable inductance elements and the usual variable capacities may be so connected together mechanically that one operating movement only is necessary for changing wave length. If desired, the usual bi-control or multi-control set may be provided in which two or more movements are necessary depending upon the operative mechanical connections provided Obviously, my invention contemplates relative movement between a coil or coils and a shield or shields however this may be accomplished.

Preferred forms. of apparatus for practicing my method of wave changing are illustrated in the accompanying drawings in which Fig. 1 is a diagrammatic representation partly in perspective of circuits and apparatus showing a receiving station provided with a variable shield inductance;

Fig. 2 is a similar view of a modified form of variable loading inductance;

Figs. 3 and 4 views of further modifications of shield inductances;

Fig. 5 is a diagrammatic view partly in section showing a modified form of inductance;

Fig. .6 is a diagrammatic view illustrating a constructional detail of one form of shield;

Fig. 7 is a diagrammatic view showing a modified form of shield inductance;

Fig. 8 is a detail side view of a modified form of shield;

Fig. 9 is a diagrammatic view partly in section showing a modified form of inductance;

Fig. 10'is a diagrammatic View showing another form of shield inductance;

Fig. 11 is a diagrammatic view partly in perspective showing a variable loading inductance and a variable coupling.

Referring to the drawings and at first more particularly to Fig. 1, A represents an antenna grounded at B and rovided with the coupling coil G coupled tlirough coil D to suitable receiver circuits having the variable condenser F, detector G, and the telephones H. The usual variable condenser J is shown in the antenna A, and K represents a simple form of shield inductance compris' ing a loading coil L and a shield O which may be in the form of a disk of conducting material as copper, and may be of any suitable configuration.

In Fig. 1 the shield O is so arranged relative to the coil L that the magnetic lines of force of the self-field of the inductance coil pass in part through said shield, and variations of current in the coil induce eddy currents in the shield as well understood, so that the shield constitutes a short circuited secondary to the coil, which maybe regarded as its primary. The effect of the shield O is in general to reduce the inductance of coil L as measured between its terminals. If the shield is moved or rotated in such a way relatively to or about any axis 0, as to change the interlinkage of magnetic flux from the coil passing through the shield, its reaction on the coilwill be changed and the effective inductance of the coil will be altered.

Theory and practice agree in indicating that the greatest reduction in the inductance of coil L occurs when the couplin between the coil and the eddy current at s set up in the shield O is unity. \Vhi e unity coupling cannot be realized, sufficiently close couplings can be obtained to cause extremely marked changes in the inductance of coil L. For example, in the modification shown in Fig. 3, which will be referred to in detail, the inductance of a coil may be reduced'to less than one twenty-fifth'of its maximumvalue by the presence of two shields.

The shield inductance K, comprising elements L and O, and the variable con=" denser J, form tunable circuit elements and obviousl they may be .so mechanically connectedthat both may be controlled by manipulation of one operating handle or member, just as in Fig. 3 two shields O are shown mechanically connected to'be moved together. The shield inductance K and variable condenser J may also be connected if desired in the receiver circuits E in any suitable manner and thus form an ordinary tuned secondary. If the range of inductance variation in such a tuned circuit is twenty to one,'and range of capacity Variation of the variable condenser in such circult is also twenty to one, the circuit in question will have a range of frequency variation of twenty to one as well. By this means a tuning element covering a substantially long range of 'frequenciesor Wave lengths wlth a single control handle if desired may be obtained. I

In Fig. 1 I have disclosed a method whereby the self-inductance of a'coil can be altered continuously by the motion in the magneticfield of said coil of a shield or massof conductin material.

'In Fig. 2, have shown the coils R and S connected in series in the antenna so that their fields assist each other. The self-field of coil R in part-passes through the shield O, as also will a part of the self-field of coil S. In addition, a portion of the mutual field of both coils will pass through the shield O. The introductlonof the shield between the coils will therefore not onlsy diminish the inductance of coils R and but will 1n addition, diminish their mutual and assisting inductance,- so that the induct-.

- ance between the terminals of the'coils will.

be markedly reduced. The motionfof the. shield as before described will give'rise to" a continuous variation in the inductance.

This construction shown in Fig. 2 is a com- I bined shield-inductance and variable shield mutual inductance. 5

ductance the variation fof which is substantially entirely due variatien" in the mutualfield between the separate portions of :this inductance. Thus, if .in"-Fig.' 2 coils'R and S are so far a art thatfthe shield Odoes not markedly c ange their self inductanceson its introduction; et it may substantially eliminate thelassistlngj mutual induc ance.

Therefore, in accordanceswith well known theory, the lntroductionjof the shield 0 will reduce the total inductance between termi- 'ish this total inductance so far as the reduction of the self inductances of the coils is concerned, but, on the other hand, tends to increase the total inductance between the coil terminals by cutting down the opposing or subtractive mutual inductance. I am well aware of the nature and use of this sEbcial disposition of inductances and s ields, and regard it a special case coming under my broad claims hereunto annexed.

It is to be understood that the shield O in the figures so far described may be moved or manipulated by any suitable form of operative mechanical means (not shown), and the outline or contour of the shield, and its conductivity are determinable at will, so that practically any desired'law of inductance variation with a given series of settings of the shield may be obtained. Furthermore, practicallyany known law of mutual inductance variation can be similarly obtained by the proper choice of the same conditions. a

Fig. 4 illustrates another practically usefulform of the invention in which the spiral T lies between two shields O andpreferably in' contact or nearly in contact with them. Under these conditions practically the entire self-flux of the magnetic lines of force of theooil Twill pass through the two shields and a reductionin inductance will be caused by the presence of the said two shields. These shlelds may be slid into or out of the field by means of the handle T and will give rise to a continuous variation of inductance between the limits obtainable withthis device.

In Fig. 4 the shield O is provided with a lug a through which passes the shaft I) having the handle a for rotating the shield about" the axis ofthe shaft b to and from.

the coil T. In so doing, the inter-linkage of vuntgn'etic flux due to coil T with the shield O', will be continuously varied, thereby varymg the. inductance of the coil.

Fig." 5 shows an arrangement wherein .flat spiral'coils g, h, j, and It, are provided. The "shields o, p, and g, may consist of flat plates adapted" to he slid nto and out of cooperative relation with the coils. coilsg and h are preferably arranged so The that their fielde assist, as are also c0ils y and 70. Furthermore, coils g and j are preferably arranged so that. their fields assist, as are also coils in and It. All four 'coils'are preferably connected in series as shown. When the shields 0, p, and g are slid opposite the coils as indicated in the figure, not only the self-fields but the mutual fields are short circuited by the inductance shields. Thus,.both. their self and mutual inductances are, to a very considerable extent, eliminated. Such sets of coils may be constructed with an unusually high maximum to minimum inductance on shielding, under practical operating conditions. Ob viously, more than four coils can be used in this way, and the two piles of coils may be extended into several piles of a very considerable number of coils vertically.

Theentrant edge or advancing contour of the shield of conducting material which passes over or into the inductance is of importance in that it determines, in part, the law connecting the motion of the shield and the inductance of the coil which is being shielded. In Fig. 6 the shield 1' which is advancing over or intothe coil 8 has an approximately semi-ci-rcular edge t, because I have found that the law of inductance them.

.It is sometimes convenient to use a shield a; which swings over a spiral inductance as shown in Fig. 7, instead of sliding'lineally over the spiral. The shield 'v of which there may be several as desired, is pivoted as u,

and the inductance is a minimum when the shield is swung entirely over thecoil and a maximum in the position indicated in the figure. In Fig. 8 is shown a generally preferable contour for a swinging shield '0, which outline gives a more gradual drop of inductance of the coil T as against angular rotation of the shield, and in ad- -dit1on,. ives a smaller increase in. the effective resistance of the coil when operatively shielded, as explained in connection with Fig. 6.

In Fig. 9 is shown a way in which double fiat spiral coils a: and 3 may be connected for use as a shield inductance. The inner terminals of the two spirals a: and 3/ are preferably connected at '2 and the spirals should preferably be wound so that their' fields, will assist with the arrangement I one anot shown. Shields 2' and 3 are adapted to slide or rotate over the spirals in one of the ways illustrated herein. The advantages of the connection of the double spiral shown are that there is a minimum increase of efiective resistance for positions of partial shielding and both terminals of the double spiral are conveniently located on the outside of the shields.

In Fig. 10 are shown two flat spirals 4. and 5 connected in series with their fields adding as in the case of Fig. 5. The shield 6 pivoted at 7 is adapted to swing through an angle of approximately 180 over both these spirals 4 and 5. By this means the inductance of both coils t and 5 will be greatly reduced and the effective inductance continuously diminished as the shield is swung through an arc of 180 from the position shown. The advantages of the arrange-' B5 ment indicated in Fig. 10. are that it enables ordinary (or slightly altered) plates of a variable condenser to be used as shields of the inductance with a very efl ective utilization of the supporting space for the coils, which gives a large variable inductance within a limited volume and area. -A pile of such units shown in Fig. 10 may be assembled to advantage as in Fig. 5. The modification of Fig. 8 will merely consist in providing rotating or swinging shields instead of lineally sliding shields, which modification was referred to in describing Fig. 5.

In Fig. 11 is shown an extension of the form of apparatus indicated in Fig. 7. In

Fig. 11, in addition to the shield inductance formed by the coil T and shield 'v, I have illustrated a combined arrangement of shield inductances for the coupling coils 8 and 9 vwhich is also a variable shield mutual inductance, because the primary coil 8 which is variable by means of the shields, is coupled to the similarly variable secondary 9 through a variable shield mutual inductance.

In this instance the shields 10, 11, and 12, are arranged adjacent and between the coils 8 and 9 as indicated and adjustably mounted by means of set screws 13 on a common operating shaft adapted to be manipulated by the handle 15 to swing the shields into and out of shieldin position. The shields 10, 11, and 12ne not necessarily be on one operatingl shaft, but may be independent of er or else mntuall interconnected in any desired manner. he construction shown forms a uni-control variable cou ler coil T may be operatively connected to the shaft 14 of the shields 10, 11, and .12 by .any suitable means as the belt or chain 16,

so that a completely uni-control device is produced. As the wave length is increased and the arrangement and shape of the various shields, shield inductances, and variable shield mutual inductances may be varied in accordance -with any of the modifications herein disclosed, or changed in various particulars in accordance with the principles of my invention, without departing from the spirit of the invention as claimed by me in the claims forming part of this specification.

While I have shown various special forms of application of a shield inductance to unicontrol or multi-control receivers and transmitters of various types, I am not to be restricted to the particular forms shown, but desire to be understood as including within my invention, shield inductances, or combi-v nations of shield .inductances and shield couplers in difl'erent forms in any receiver or transmitter to which they are appli cable. The application of this principle as applied to vary the coupling in" any receiver or transmitter is made the subject matter of my copending application Serial No. 314,480.

I claim and desire to obtain by Letters Patent the followin 1. A variable inductance for high frequency currents comprising, 7 a pair of spaced coaxial parallel air core coils connected together and a flat shield of conducting material located between said coils, said coils and shield being slidable relative to each other in a direction transverse to the axis of the coils.

2. A variable inductance .for high frequency currents comprising an air core coil and a flat shield of conducting material in the magnetic field of said coil, said coil and shield being slidable relative to each other in a direction transverse to the axis ofsaid,

coil and a fiat shield of conducting material substantially parallel thereto and slidable relative to each other in a direction transverse to the axis of said coil.

4. A' variable inductance for high frequency currents comprising a fiat a'ir core coil and a flat shield of conducting material substantially parallel thereto, said shield being adjustable in a direction transverse to the axis of said coil to cover various sections of the surface of the coil.

5. A variable inductance for high frequency currents comprising a flat air core coil and a fiat shield of conducting material substantially parallel thereto, said conducting body being slidable about an eccentric axis in a direction transverse to the axis of said coils.

6. A variable inductance for high frequency currents comprising a flat air core 7 coil and 'a fiat shield of conducting material substantially parallel and in close proximity thereto, said coil and shield being slidable relative to each other in a direction transverse to the axis of said coil to cover various sections of the surface of the coil.

7. A variable inductance for high frequency currents comprising a pair of adjacent fiat substantially parallel air core coils connected together and in close proximity and aflat shield of conducting material intermediate to the coils, said coils and shield being slidable relative to each other in a direction transverse to the axis of said coils to cover various sections of the surface of said coils.

8. A variable inductance for high frequency currents comprising a pair of adjacent fiat substantially parallel air core coils connected together and in close proxmateimity and a flat shield of conductin rial slidable between the coils in a direction transverse to the axis of said coils.

In testimony whereof I have signed this specification.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2468126 *Jul 11, 1945Apr 26, 1949Standard Telephones Cables LtdFrequency scanning arrangement
US2521963 *Aug 27, 1945Sep 12, 1950Beusman Robert MInductance capacity tuner and circuit therefor
US2531313 *Jun 22, 1944Nov 21, 1950Honeywell Regulator CoOscillator and oscillator-controlled relay system
US2583941 *Nov 13, 1946Jan 29, 1952Jr Thurlow M GordonDevice for detecting variations in fluid pressure
US2629860 *Aug 5, 1949Feb 24, 1953Chesus Frank OInductance tuning unit
US2669653 *Apr 12, 1950Feb 16, 1954Collins Radio CoCyclotron tuning apparatus
US2793256 *Mar 31, 1952May 21, 1957Commissariat Energie AtomiqueElectronic amplifiers
US2967238 *Apr 10, 1957Jan 3, 1961Standard Coil Prod Co IncTuner for television receivers
US4352111 *Jan 26, 1981Sep 28, 1982Rca CorporationMulti-band antenna coupling network
DE966235C *Nov 24, 1942Jul 18, 1957Siemens AgElektrische Spule fuer symmetrisch aufgebaute Schwingkreise, deren Induktivitaet einstellbar ist
DE1088104B *Aug 29, 1958Sep 1, 1960Sea Soc Elec Et AutomatismeSpulenanordnung fuer Nachrichtenanlagen
DE1141382B *Dec 20, 1954Dec 20, 1962Philips PatentverwaltungEinrichtung zur Induktivitaetsaenderung
U.S. Classification336/79
International ClassificationH01F21/00
Cooperative ClassificationH01F21/005
European ClassificationH01F21/00A