US1573374A - Radiocondenser - Google Patents

Description

Feb. 16 1926. 1,573,374

P. A. CHAMBERLAIN RADIOCONDENSER Filed July 2, 1924 3 Sheets-Sheet 1 Feb. 16 1926.v

P. A. CHAMBERLAIN RADIOCONDENSER Filed July 2,

5 Sheets-Sheet 2 Y/l/l/l/l//ll/A l;

Z?? fo 7j inde/LZ( (canberZZl Feb. 16 1926.

P. A. CHAMBERLAIN RADIOCONDENSER Filed July 2, 1924 3 Sheets-Sheet .'5

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Patented Feb.- 16,'v 192e.

. `1,573,374 PATENT OFFICE.

:PAUL A.. CHAMBERLAIN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO ELECTRICAL DEALERS SUPPLY HOUSE, INC., O IF CHICAGO, ILLI- NoIs, A CORPORATION OF ILLINOIS.

RADIOCONDENSER.

Application led July 2,

in multiple circuit controlling devices for radio apparatus and more particularly to condensers adapted for use in multiple circuits and has for its principal object to provide an improved form of apparatus of the class described'inwhich two orm'ore condensers each coupled in a separatecircuit, as for'ins'tance, in successive amplification stagesof a'radio receiving or sending set, may. bei all adjusted-and the respective circuits bal'anced so as'to afford lsimultaneous control of the circuits by manipulation -of` a single controlling -memben For the purpose of illustrating vmy im'- proved apparatus, I have shown it as applied to a 'standard hook-up for amplification of radio-frequency currents vin a radio receiving set in which the separate audion amplificationv circuits are tuned by varying the capacities of each grid circuit. It is well known by those vfamiliar* in. the art'vthat the advantages v'of ,controlling such "coul densers by' a single controlling-device are self evident, yet 'it 'has' been found quite difficult to produce satisfactory, unitary control apparatus -of this character in commercial quantities vfor thereason that severalvariable -and-uncertain factors are established Yduring construction of each apparatus'. Awhich factors are not subjecttoready control or measurement,even.though great care be exercised to' conform *to uniform specifications and st andardsof construction. These factors will be hereinafter more fully discussed in connection with'my improved means and method of;v` offsettingthe combined -effects ofsuch factors'.l

My invention contemplates the provision of a novel arrangement of. circuitsv and method of"adjust1ng the same, whereinmeans are provided for independently A'adjusting the vca acitieso-f a plurality of condenserunits w ich adjustment is made after the apparatus is wired and completed so that the circuit condensers and theirrc- 1924.- serial No'. 72213617',`

spective circuits are balanced Or phased to the same periodicity with respect to each other. This'balancing of the several capacities will offset the combined effects of the several uncertain and variable factors already suggested. Another-feature of the invention is the provision Ofnneans for shielding the several condenser units from each otherthereby permitting such units to be mounted in relatively' close relationship with each other, as for instance, in axial alignment .with each other on a common shaft, thereby eliminating the effect of.

capacity coupling between the separate circuits a't this point.

rlhe invention -may be best understood by reference to thev accompanying drawings in which: i

Figure 1 iis-a plan View of Oneform of condenser construction in accordance-with `my invention.

i Figure 2 is-a sideview of the condenser shown in Figure l. i

Figure 3 is an end view of the condenser shown in Figure l with a part broken away to show oneend of .a shielding plate. i

Figure 4 is a section taken on. line 4 4 of Figure 3..

Figure 5 lis .a planl view' of a vmodified form of condenser in this form thebalance and shield adjusting plate is movable with the roller. l

Figure 6V is an end viewof the condenser shown in Figure 5.

- Figure 7' is a detailtaken lon line 7-7 of Figure 5.

Y Figure 8-is a diagram nshowing a typical application "of my invention to'a portion of a radio frequency'4 amplification apparatus.

Figg) is an enlarged diagram of the condenser construction.

Referring -now` tof details shown on the drawings, Figs@ tod illustrateya preferred form of-condenserwhich 4may be used 1n carrying out my Inventlon'. This condenser comprises a frame consisting of metal end lms ' condenser units; in the ornrillustratcd here# necting member comprising rodll secured to the end plates by screws 17, .-17. The. structure is provided. with a plurality of in two such condenser units 18 and 19 aref/shown, the firstof ,which consists of a stator made up of a plurality of parallelly disposed plates 21', 21 spaced apart, anda rotor element'made up of a plurality of plates 23, 23 interposed between adjacent 'stator plates. This'condenser unit thereforefcomprises an Aair gap condenser of the usual construct-ion,l the stator plates being substantially' rectangular and y the rotor plates .being semi-circulan in shape. The rotor plates are rotated so vas to vary the capacity of the condenser in 'the usual manner. The second unit 19' consists of a similar `arrangementof stator plates 25 'and rotorVv plates-2 6. v'In the form of condenser shoivn in figure, the stator plates '21, 21 -ofcondenser i gagement fr alimited portion thereof,.as

for instance, adjacent the sides of-the blocks, While the intermediate portion of said-l supi porting rod is reduced in diameter as indicated at' 33;thus providing a limited contact between the supporting rod and the insulating'block-to reduce electrostatic losses between the stator-platesand the frame to a minimum. The stator plates may be supportedvon the insulator blocks 30-30 by any suitableF neans, 'for instance, in Fig. 3, it

l will-be seen that said plates are's'ecured to pieces 34, 34 of conducting material, 'as for instance by welding, said block pieces being vmounted on the inner faces 'of the insulator `30 30 by means of screws S5-35. Terminals 36-36 provide connection for the respective stator velements of condenser units 18 and 19.

i The rotor plates of condenser units 1 l and 19 are mounted on the common shaft 4.0v inthe usual 'mannerand the" shaft has bearing in end plates 10 and 11 by'any suitable means, as, for instance, the bearing on plate- 10'consists of a. ball bearing 41 adjustable by a screw 42, while the opposite end of the Ashaftis provided with aA split threaded bear.

ing 43 adjustable bva nut 44 to vary the tension on the shaftin the` usual manner.

The shaft .isprovided by a prolongation 45 Y adapted to extend through a panel 46 in the usual manner for connection to a dial or similar manual adjusting device.

'Referring noW "to theparticular features `of novelty forming a` part of my invention,

"it will be observed that I provide an electrostatic balancing adjustment between adjacent condenser units. The balancing means consists of a pair of' plates50 and 51, interposed between and' adjustable toward and awayA from the plates of the adjacent condenser units I8 and 19.` vIn the form shown in Figures 1, 2 and 3, .these balancing plates are substantially the same as the rotor plates in general outline and are given their lateral adjustment by thumb screw mountings at opposite sides of the condenser. These '-mountings consist herein of a pair of thumb.

screws 52-52 threaded on the supporting rods 31, 31 and having annular slots 53, 53 in which recessed portions 54 yof the balance plates are carried. As will be' seen from the drawings,x the plate`50, may be moved toward and-.Naway from theadjacent condenser unit 18 as desired, While the other plate 51 shunt condensers. In the particular 'dia-v gram illustrated, I have shown connections for portions of two stages of radio-frequency amplification. The grid circuit of the first stage includes the grid 60 in an audion 61, a grid lead 62 to asecondary coil 63 of an input-transformer 59. A grid return lead 64 connects said secondary coil to a negative filament lead 65 of audion filament 66. This negative lead connects with the .negative si'de of A battery 67 and may also go to ground 68. The plate circuit of the first audion includesy the plate 70 and its ,lead 71 to primary 72 of transformer 7 3, thence by lead 74 to plus side of A battery 67 through B -battery 75. The filament 66 connects with plus A battery throughv rheo-r stat 78 and leads 77 and .79. The second audion 80 has similarly 'arranged grid and 4-lead 82, and grid return 83. The plate circuit constitutes an output in the usual manner.

type of condenser units will scribed.

One of the commonly used methods of now b e de- The use and application of the improved tuning successive amplifying stages as herein illustrated isby means of c ondensers shunted from the grid lead to the grid return lead of each grid circuit. j

Among the principal factors which have been-shown to effeetthe tuning of the separate circuits are (a) the electrostatic capacity of each circuit. This depends upon the relation of the several leads and other parts of the circuit and may vary considerably as between circuits, even though conL electromagnetic effects in each stage caused by the relation of coils and leads thereof either in the grid circuit, plate circuit, or both circuits of each stage. (d) There is furthermore, electromagnetic coupling between adjacent stages which has considerable effect in varying the inductances of the several stages. (e) There also may be variations due to differences or defects in the apparatus employed in successive stages, including the differences in capacity of audions, thus making it extremely diicult to assure the desired.V uniform capacity and inductance values to be controlled by the condensers. Capacities of the condensers themselves may vary somewhat. (f) The 'resistance values may also vary considerably as between separate circuits or stages, as, for

vinstance, in the case of defective connections,

contacts, etc. Furthermore, experience demonstrates that it is extremely diflicult to den tect the controlling elements which cause these various differences in each particular instance.

From the above discussion of the many variable factors, it will be now understool why it is generally considered impracticable to control all of these factors with such de# gree of certainty as to insure uniform 4changes in several condenser units used to tune the separate circuits of the apparatus, even though \these condensers be exactly equal in capacity. In other words, it has been demonstrated that these factors. are established during the manufacture of the apparatus, and vary so greatly with each set, that it has been found. practically impossible to secure substantial uniform tuning effects in the separate circuits by varying separate condensers uniformly, even though the condensers are' Aof substantially the same capacity.

F or these reasons it has usually been `the practice to tune each of such amplification stages by means of independently operated condensers.

M v Improved form of condenser includingr balancing and shielding means as described is designed to provide an. adjustment to readily compensate for the varying factors above discussed. In the typical circuit shown in Figure 8 this is accomplished as follows:

The stator of condenserl unit 1S is connected by lead 86 to grid lead 62 of the first amplifying circuit, and the second condenser unit 19 is connected by lead 8T to grid lead 82 of the second amplifying circuit. The rotor 40 of the condenser is connected through lead l to the grid return lead Gl which is inl turn connected to both minus filament leads of the two amplifying stages. Since the grid return lead 83 is also connected to the second minus filament lead, the rotor thus provides a common connection t-o the two grid return leads, andfurther-4 more, provides a common ground at 68, when such ground connection is used.

New, when the circuit is fully completed, the inductance and capacity values of the first and second stage grid circuits usually vary from their desired equal ratios, due to the effect of the several factors hereinbefore discussed. By the provision of the adjustable balancing plates and 51, however, the relative capacities of the two condenser units and their respective circuits may be balanced to approximate equality, and thus bring their respective circuits int-o phase or resonance at all points of tuning by various means, the simplest method being that of tuning the set to receive a given signal, and then adjusting the two balancing plates so that the critical point of maximum tuning of each circuit coincide at oneposition of the rotor. In other words, said plates are adjusted so that the points of maximum volume of the separate amplifying stages are coincident on the single tuning dial of the condenser. This adjustment may be readily made by anyone skilled in the art, and once made, no further adjustment is necessary for all ranges of the two condenser units, so long as the internal capacity and inductance values of the separate circuits remain unchanged. This semi-permanent adjustment of capacities of the two condenser units 18 and 19 is indicated in Figure 8 by the dotted arrows, while the full arrow indicates that the entire condenser including said units 18 and 19 may be Varied by a single adjusting means such as a dial, to tune the set to various, frequencies or lwave manner.

In the enlarged diagram 1n Figure 9 the lengths in the usual construction of the condenser is illustrated in greater detail showing diagrammatically the arrangement of the separate elements of the condenser units 18 and 19 including the rotor plates, stator plates and balancing plates.

'mon rotorshaft is employed, and it is desired that the overall length of the condenser be restricted tocompact limits.

In the form shown in Figures 5 and 6, I have shown a modified Vform 'of condenser which may be used in carrying out my invention.

In this form, the balancing plates are carried upon the rotor instead of being carried upon the condenserframe as in the first form herein described.

Inthe second form'of condenser, the

frame comprises a pair of' insulated or non-l conduc't'ing end plates 90 and 91. The condenser units 18*` and 19a each comprises stator plates 94, 94 supported n spaced relation on a plurality of supporting bars 92 and 95. The bars 92 are supported on the end plate 90 and the opposite bars 95 are supported on. end plate '91.- In this form of condenser' the condenser units are insulated from each other by providing insulating members, 96, v96, .in alignmentl with each pair of supportingr bars 92 and 95. These bars have reduced end portions 92a and 95a extending in theopposite ends of the holes 9.8 in the insulating members and spaced apart therein, as shown in Figure 7. The entire frame is clamped together by a securingr means such as rods 99, 99 spaced from the stator plates as best shown 4in Figure 6. The rotor comprises two sets of rotor plates v100 and 101 ofthe usual semi-circular form carried on the shaft 40a,

in the usual manner. A These sets of rotor plates are interleaved with the ystator plates of the respective condenser units 18a and 19a in `the usual manner. The balancing plates a and 51aL are mounted for longitudinal adjustment on the threaded portion 107 of the yshaft 40a intermediate the con-l denser units 18a and 19, This adjustment is afforded byv suitable means such as threaded members 97, 97 and lock nuts 108, 108 associated therewith. In this form of condenser the balancing plates are preferably circular inshape as shown, inasmuch as they are movable with the rotor and itV is. desirable -to have these plates interposed between adjacent stator lplates in all positions of the/'rotor so as to provide uniform capacity coupling between said plates and condensenunits as well as the desired shielding of thecondenser units from leach other. It will be manifest that in case only two circuits, including their respective condenser units, are employed, the desired balancing may be accomplished as between the two units by the use of a single balancingseparate `condenser units having a common rotorand all controlled by al single dial, but with balancing plates interposed between each pair lof adjacent condenser units for adjusting the respective values, in the manner already described in connect-ion with two such condenser units.

It will be understood that my invention is not limited to the tuning of successive grid circuits as illustrated herein, but is capable of the use in many variations of radio apparatus, in which it is desiredi to vary several capacities in substantially uniform decrements, while compensating for the uncertain variable factors of distributive capacity, etc., established in the manufacture of each set. l

I claim:

1. In an apparatus of the class described, a condenser provided with capacity elements movable relative to each other, one of said elements comprising a plurality of insulated units, andI means interposed between adjacent units and conductively connected to the'other of said elements, and adjustable 'inposition relative to saidinsulated units to vary their respective capacity, ratios.l

2. A condenser comprising a frame, a rotor and asta-tor, the stator being divided in a plurality of condenser units insulated from each other and spaced longitudinally of said rotor, and'means electrically connected with said rotor and interposedbetween adjacent condenser units for shielding said units from effects of intercapacity coupling therebetween.' v

3. A condenser comprising a frame, a rotor and a stator, thestator being divided in a plurality of condenser units insulated from each other and spaced longitudinally of said rotor, and7 meafns electrically' connected with said rotor and interposed between adjacent condenser units, said means being independently adjustable toward and away from their respective unitsto vary the-incapacity ratios.

4. Inan apparatuspf the class described,

a -condenser comprising a frame, a plurality of stator units supported .on said frame in spaced relation and insulated from each other, a rotor comprising a` plurality'of members each cooperating in capacitative relation with said stator units, and balancing means mounted on said rotor intermediate adjacent condenser units and adjustable longitudinally of said rotor.

5. A variable capacity device comprising a plurality of condenser units, each unit having a rotor element and a stator element, common means for operating the rotor ele-` ment of each unit, a ,conductive plate, in addition to said elements, and means for supportingsaid plate between said units and for adjusting` the same along the rotor axls.

6. A variable capacity device comprising same to said means.

8. A variable capacitydevice comprising a plurality of condenser units, each unit having a rotor element and a stator element, common means for operating the rotor element of each unit, a pair of conductive plates, in addition to said elements, and means for sup orting said plates between said units and or adjusting the same along the rotor axis relative to each other and to the said unit. y

9. A variable capacity device comprising a plurality of condenser units, each unit having a rotor element and a stator element, a common meanssupporting a similarone of said elements in each unit and a pair of conductive plates between said elements and ad- `justably supported byf said common' means.

10. A variable, capacity device comprising a plurality of 'condensers each having a vrotor and a "stator, common means foryoperating all said rotors in unison, and Ya conductive plate interposed between the condensers and\adjustably spaced along the common rotor axis from the stators thereof.

1l. A .multiple variable capacity device comprising a frame, a plurality of stators carried in spaced relation by said frame, a shaft mounted for rotation in said frame,` a plurality of rotors carried by said shaft and each cooperating. with a corresponding one of said stators to provide a variable capacity upon rotation of the shaft, thus constituting a plurality of condenser units, and additional condenser elements disposed between, and

4arranged to coo crate with, said condensers,

to shieldthem rom one another and adjustable -to vary slightly the relative capacities of the condensers.

l2. A condenser comprising a frame, a plurality of stator units spaced longitudinally of said frame, yrotor units in capacitative relation with said statoi` units and mounted on a common shaft, each pair of `stator .and rotor units having cooperating surfaces in capacitative relation witheach other of area substantially equal to cooperating surfaces ofthe other pairs of stator and rotor units, and all of said capacity areas being variable in uniform decrements as said common rotor isrotated, and means,

associated with each pair of said rotor and stator units and electrically common with one of said units, permitting relative movement of a capacitative area toward and away from a cooperating capacitative area of the other unitin a directi vrparallel with the axis of rotation of said common rotor units, whereby the capacity ratios of said rotor and stator units may be independently varied,

ybut theV angular relation between each set of rotor and stator units will be uniform for all pairs thereof in any position of rotation ofsaid common rotor.l

Signed at Chicago this'25th day of June, 1924.

PAULA. oHAMBERLAIN.`

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