US1614428A - Variable condenser - Google Patents

Description

11 1927' F. o. HARTMAN VARIABLE CONDENSER Filed Nov. 5. 1925 6 sheets-Sheet INVENTOR, Z gfizrz zizayz ATTORNEY.

Jan. 11 1927.

F. o. HARTMAN VARIABLE CONDENSER Filed Nov. 5,

1935 6 Sheets-5heet F'. 0., HARYMAN VARIABLE CONDENSER Filed Nov.

5. 1925 6 Sheets-Sheet 4.-

Jan. 11, 1921. 14,42

F. o. HARTMA N VARIABLE CONDENSER I Filed 3 v. 5. i925 6 Sheets-Sheet 6 t v m l '0- l l l l l i ih 3 w "vi amok ATTORNEY Patented Jan. 11,1927.

UNlTEDfSTATE'S PATENT oF ijca.

FRANK o. HARTMAN, or maasrmm, OHIO, lissreuoa TO THE HARTMAN memcn. manomc'ronmo comr'amr, or museum onto, A coaromrrron or 01:10.

VARIABLE commnsnn.

Application filed November 5, 1925. semi No. 67,152)

My invention relates broadly to electrical tuning systems and more particularly to a construction of timing apparatus for use in radiov broadcast reception,

One of the objects of my invention is to provide a construction of tuning apparatus for radio reception by wh ch a number of electrical circuits may be simultaneously circuits for the correction of differences controlledbv a central adjustable unit.

Another object of my invention is to provide a construction of. variabletuning device for the s multaneous 'control of electrical circuits, wherein provision is made for accurately balancing the several-electrical the capacity characteristics which may exist therein.

Another object of my invention is to providea construction of variable condenser in which a multi-bladed rotor is provided working into a like number of stators with independently adjustable meuns associated with each of the sets of stator 'plates' and arranged to be s acially regulated with. respect to indepen ent cooperating adjustable plates, connected to the several circuits under control-foraccurately com ensating for difi'erences in the capacity 0 aracteristics thereof.

Stillanother object of my invention is to provide a construction of variable condenser in which a rotor .having a multiple number of rotor platesthereon, may be accurately interleaved with a like number of inde pendent sets of stator-plates for simultaneously'varying .the tuning of a plurality of independent circuits.

My invention finds particular application in the s'niultaneous control of a plurality of clectron'tube circuits of a radio frequency amplifier in a radio receiving apparatus for radio broadcast reception. In apparatus of this kind it iscustomary to provrde anumber of tuning dialswhich control variable condensers which are. arranged to-tune the input circuits of a plurality of electron tubes in succession. It is generally impractical to connect all of these condensers directly on the same shaft for simultaneous operation by reason of the ditleycnr-es m the characteristics of the various circuits. T provide 111021115: for sinmltaneously tuning the several electron tube c'rcnits, and independent adjustable means tor-compensating for the differences in the several circuits. I have accomplished these results by a particular con-.

s truction which will be described in detail in the s e'eification hereinafter following. I desire t at it'be understood however that I do not intend my-invention to be limited to the particular construction illustrated, but that my invention is entitled to the full scope of mechanical equivalents.

I provide a rotor having a, plurality of rotor plates projecting froma .bentral shaft in a number of sets corresponding to the number of circuits which are to be controlled. The central' shaft of the rotor plates is journaled forrotation in such manner that the sets of rotor plates may be interleaved between correspondin sets of stator plates which project inwardfiy toward the central shaft, but are substantially insulated therefrom. On the rear of each of the sets of stator plates I provide a plate extending substantially at right angles to the plane of the stator plates in such posiconstituting'the stator and rotor of the variable condenserpermitsthe circuits to be so arranged that'accurate compensation of the several circuits may be made corresponding to differences in the electrical characteristics of the several tubes and condensers and inductances in the circuits and then the circuits simultaneously tuned by rotation of the central shaft. The details of construction of the several parts of the condenser comprising my invention will be more fully described hereinafter, by reference tothe following specification and the accompanying drawings, in which: v i

Figure 1 is a front elevation of a tunin apparatus which includes the principles 0 my invention; Fig. 2 is aback view of the tuning apparatus showing the arrangement of the several sets of stator and rotor plates; Fig.3 is a side elevation showing the operating parts of the variable condenser in the tuning system of my invention;-Fig. 4 is a detailed cross-sectional view taken on line 4--4 of Fig. 2 and'illustrating one of the compensating capacity units employed in the tuning apparatus; Fig. 5 is a fragmentary cross-sectional view illustrating v the construction of the compensating capacity unit arranged to control from the front of the ill which is covered by a plate 2.

tuning panel of the tuning apparatus taken on line 5 of Fig". 2; Fig. 6 is a central vertical section through the condenser showin the rotor mounting; Fin. T is a vertical ion tal'enon line T-7 of Fig. 6; Fin. 8 is adetail vertical sectional view taken on line 8 -3 of Fig. 6 showing the construction of the gearing intermediate the rotor and the indicator dial of the apparatus; Fig. 9 is a rear plan view of a ,Inodilied construction of tuning condenser; Fig. 10 is a side elevationof the condenser construction illustrated in Fig. 9 Fig. 11. a central vertical section taken through the rotor of the variable condenser construction illustrated in 3; and Fig. 12 is a wiring diagram ing the arrangement of the tuning apparatus oi my inven ion in a radio receiving circuit. H

Referring to the drawings in detail, the apparatus panel is designated by reference charact 1 having a sight opening i) therein The panel has a centrally positioned sight mark 4, with reference to which the calil ations on a retary dial 5 may be read through the sight opening-.3 from the front of the apparatus. A control knob 6 projects through the front oi the panel for controlling the movement of r the stub shaft 9 through the intermediary of a major. gear 12 with which a pinion 14 1s meshed... Control knobs 10 and 11 also project. throng-lithe. apparatus panel 1 and are controlled from the trout thereof. The apparatus panel 1 is cut out or counter-sunk, as represented at to permit the dial 5 to be ireely rotated therein. The variable condenser is mounted upon a panel lti which is suitably secured to the rear of the apparatus panel 1. I have illustrated a plurality of screws 17 which serve to position the supporting plate 16 to the rear of the panel 1. A hub 18 is central y positioned upon the plate 16 providing a central support for the stub shaft 9. The shaft 9 has an annular shoulder 19 which abuts against the face of the projecting hub 18 and is secured rigidly 'thereagainst. by means of a nut 20 which is screw threaded upon the end of the shaft 9 bearinf' a qainst the front tare oi the panel 16. The stub shaft I? is substantially larger indiameter throughout one portion of its length forming a bearing portion 21 with a 1 head?) at the end thereof. The rotor plates an end pl rotor plates may be secured with minimum friction of parts. That is to say, the

space 2? may be filled with a lubricating grease well packed so that it is effective over a relatively long period of time. The method by which the rotor plates are varied in angular position will be more clearly understood by reference to the details shown in Figs. (3 and S. A pair of U shaped plates and 23) are secured on opposite sides of plate 16 forming a housing for a bearing 30. The bearing consists of a substantially rectangular block havin a bore therethrough in which is journaled the operating shat t. In Fig. 6 the control knob 6 is shown having its shaft 6 passing through the bore in the block 30. The block 30 is substantially reduced at its opposite ends and fits snugly in an aperture in the U shaped plate 28, but in a position for vertical displacement in U shaped plate 29: by reason of the elongated aperture :11 in the'U shaped plate 29 and the relative pivotal mounting of the opposite end of the bearing block in the U shaped plate 28; The bearing block 30 is spring-pressed by the resilient means indicated at 32 in a direction toward the major gear 12 whereby pinion 14 is constantly urged into engagement with the gear 12. The indicator 5 is geared to be rotated with the angular dis-Y placement of the rotor plates 23 through the intermediary of pinion 33 o'f-shaft 34. The shaft. ill; is journaled in a bearing block '35 which is positioned between U shaped bracket members 536 and 37. The bearing block 35 is substantially rectangular and fits snugl into a correspondingly shaped aperture 38 in bracket '36. The ends of the bearing block are substantially reduced in width, enabling the block to be snugly titted between the bracket members 36 and 537. The end f the bearing block 35 which projects into the bracket 36 is provided with rounded edge faces 3.) enabling the bearing block to rock in the bracket 36 in the mahner of a pivotal mounting. The bracket 37 has a rectangular aperture 40 which is elongated in a vertical direction. The bearing block 35 is normally spring pressed by means of spring 41 which throws the bearing, block 35 to on side in the direction of the stub shaft 0. This tendency results in maintaining the major gear 12 and pinion 533 in mesh and under uni'l'orm tension tl'lroughout all positions ofangzular displrurment of the ro tor plate 23. l: may provide a suitable stop member 42 mounted in fixed relation with respect. to the plate 10 and arranged to to operate with the projecting end 43 ot one of the bolt members 26 i'()-,])l.'t('ill(lt the X'Oik tion of the rotor plates ihrougrlrany gr ater ainric than 360 degrees in one direction. it

may be desirz le to have the rotor Upt'lziib in either direction through more than ih'il) degrees in which event I omit the stop construction. It will be observed that I have shaped the rotor plates to provide a plurality of sets of lates projecting outwardly from the stub s aft 9. I do not wishto be limited to any particular number of these sets of plates, as I have illustrated in Figs. 2, 3, 6 and 7, a triple set of plates while in Figs. 9 and 10 I have shown two sets of plates. The number of sets of plates is directl dependent upon the number of individual circuits which are to be adjusted. In Figs. 12, I have shown a radio receivin apparatus including three stages of ra io frequency amplification and accordingly I have illustrated three sets of plates.

Referring more particularly to Fig. 2 of the drawings. I have illustrated three independent sets of statoialplates 44, and 46 which pro'ert inwar y toward the stub shaft 9 an having their edges tapered substantially parallel with the edges of the rotor plates 23, when the rotor is in 1mmmum capacity position with respect to'the stator plates. The stator plates 45, are shown built up On extended bolts 47 which extend at substantially right angles to the insulated strips 48 and upon which are alternately positioned the stator plates 45 and spacing members 49. The sets of stator plates are each insulated from the su porting plate 16 in a manner as describe reference to the stator plates 45, that is, the set of stator plates 44 is'insulatingly mounted with respect to the supporting'plate ,16 by means of the. insulated strip 50, while the insulated strip 51 supports th stator plates 46. The insulated strips 48, 50 and 51 are suitably spaced from t 16' by members 52 which form supporting feet beneath opposite ends of the strips. The stator plates 44 are built up on the vertically extending bolt members 53ancl 54.

while the stator plates 46 are built up on the projecting bolt members 55 and 56. In order to compensate for-'diflerences in the electrical circuits with which the condenser is connectedindependent of the tunin obtained by the angular displacement o rotor plates 23 with respect to the stator plates 44, 45, and 46, I provide fixed plates 57, 58 and 59 which extend substantially at right angles to the sets of stator plates 44,

45 and 46 along the rear thereof and; are

supported with respect thereto by tongue extensions which engage the ends of the bolt members which support the stator plates. That is to say, plate 57 is provided with extended tongues 57 and 57 which are secured over the ends of the supporting bolt members 47 and 48. Plate 56 is pro-.'

vided with extended tongues 58 and 58 in the upper corners of the plate and extending substantially at right angles to the surface of the plate in such manner that the tongues may be secured upon the supportwith 1 ie supporting fplate,

mum capacity.

tended supporting bolts 53 and 54. It will" thercfore be seen that the rear sides of each of the sets of stator, latcs 44, 45'a1id 46 are substantially closed y means of plates 57,

58 and 59. Cooperating plates 60, 61 and 62 are mounted adjacent each of the plates 57, 58 and 59 are supported from the base 16 by means of tongues which are bent at right angles to each of the plates. That is to say, plate (30 is provided with tongues 60* and 60 which supportthe plate substantially at rightang les with respect to the base 16. Similarly, plate 61 is rovided with tongues 61 and 61 exten ing .atright angles to the plate and securing the plate on the supporting base.16 substantially at right angles to the rear edges of the Likewise, plate 62 is provided with tongues 62 and 62 supported in spaced relation to the plate 59 which closes the rear edges of stator plates 44. There is sufficient from each of the lowerportions of lates 60, 61 and 62 to give the plates su cient resiliency to enable the plates to be mechanically flexed or varied in special relation with stator plates enabling'the plate to be va0 y material cut away I respect to the plates 57, .58 and 59. The mewhich an adjustable screw 64. is threaded 'chanical flexing of these plates may be seengaging one side of the plate 60in such manner that the plate 60 may be moved from its full line position in Fig. 4 to its dotted line position 60 which is a position of maxi- In this manner differences in'the characteristics of the electrical circuits may be compensated. The adjustment of spacial relation of the plate 60 and. 57 is; s own as being obtained wholly-within the with which the condensers are connected lio cabinet 65 which houses the tuning {appaf .ratus. In order toadjust the bapacity .val-

ues between the other sets (if plates-operating; means 10 and 11 are jactuated I provide cam members 11'- and 10 oh the shafts 1'1". and 10 which extend through the bearings 11 and 10 supported from the \base plate 16, and which operate to vary the spacial relation of the plates. By varying the anigular displacement of the operating means 10 and 11, the spacial relation between lates 61 and 68 and 62 and 59 may .be suitably varied to secure the desired compensation to enable simultaneous control of all of the circuits. In '5 I have illustrated the limits otthe compensating adjustments as sets of stator plates 67 and 68.

In the modified construction of the tuning condenser illustrated in Figs. 9, 10, and 11, a sub-panel (56 of insulating material may be supported in spaced relation to the instrument panel 1 carrying the independent The rotor plates are shown as comprising two sets and 70 extending in diametrically opposite directions and supported in spaced relation by spacing members 71 carried on shaft 72. The shaft 72 may be provided with a conical bearinp member H which is secured by suitable means 75 to the sub-panel 66. The desired position of the extensions 69 and T0 of the rotor plates may be secured by adjusting nut 76 on the threaded portion 7? of the shaft T2 against the spring washer 76. In this manner the rotor plates may be set to a position exactly intermediate the stator plates 67 and 68. The shaft 72 may be suitably controlled by knob 78 from the front of the panel 1. In the operation of my invention the variable condenser when employed as a uni-control for the circuits of a radio receiving apparatus has the connections arranged as illustrated in Fig. 12 where electron tubes 79 and 80 are arranged to function as radio frequency amplifiers while tube 81 operates as a detector and tubes 82 and 83 function as audio frequency amplifiers. The receiving apparatus is shown connected to an ZIHtQiLu. system 8% and =nn'd 85. The radio frequency ainplifier is shown constructed according to the principl in my 00- lending application t. 42,556, file July 9. H925,

and entitled Radio receiving system. The input and output circuits of each of the electron tubes are shown coupled through toroidal transformers 86 and 87 while the antenna connection to the receiving set is coupled through a toroidal winding 88 all of which are described in detail in the above referred to co-pending application. The toroidal winding 88 and the secondary windings S9 and of toroidal transformers S6 and 87 are all tuned simultaneously. The rotor plates 23 of the condenser are all connected to one end of each of the windings 8F, 89 and 80. y The stator plates 44. 45 and 46 are each connected to the opposite ends of the windings 88, 89 and 90. The plates 57, 58 and 59' are illustrated as elect ically connected with each of the sets of stator plates 4c 45 and 46 as hereinbeforc described, while plates 60, 61 and 62 are variably related to the aforementioned plates and each connected to the ends of windings 88. 89 and 90 which are common in-the rotor plates 23. It will be seenthat for different characteristics"of the electrolrtubcs T9, 80 and 81 that the capacity values between plates 60-57, 5S-{il'and ill-62 may be so adjusted as to compensate for differences in the electrical characteristics of the tubes so that simultaneous and equal adjustment of the several tuning circuits may be secured by angular displacement of the rotor plates 23 with respect to the stator plates.

The auxiliary or individual tuning condcnscrs do more than take care of the variation in the internal capacity between elements of the respective tubes. They make up for the variation in distributed capacity of the tuning condensers which coin rise the simultaneous control feature. Con ensers cannot. be practically made which are identical in capacity and with the positioning of the toroid coils there is also an unequal distribution of leads. The different length of leads together with the dillerence in condenser capacity values add to the variation in capacity of the tube elements and it is this total "ariation that my core denser construction compensates by means of the'individual condensers.

While I have shown my invention as par ticularly adapted for the control of multipie tuned radio frequency electron tube amplifier circuits it will be understood that the variable condenser construction of m invention may be employed for the simu taneous adjustment of various electrical circuits and that I intend no limitation upon the application of my invention. While I .have described the variable condenser construction in certain Specific details, it will be understood that modifications may be made and that no limitations upon the invention' are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows I r 1. invariable electrical condenser comprising in combination a central rotatable member, a plurality of rotor )lates projecting radially from said rot-ate le member, a plurality ,of stator plates arranged adjacent said member and insulatingly supported with respect thereto, said stator plates being disposed in the same plane with sui'l rotor platesg and auitiliary condensers connected across said cooperating sets of stator and rotor plates and disposed substantially at right angles with respect to the plane of said plates, whereby the mutual capacity between said cooperating sets of rotor and stator plates may be simultaneously varied by angular movement of said rotor plates with respect to said stator plates, and differences in electrical capacity compensated for by independently actuating said auxiliary condensers;

A variable electrical condenser comprising in combination a plurality ofsets of rotor plates arranged to interleave with a plurality of sets oi cooperating stator plates disposed substantially in the same plane therewith for simultaneously varying the "mutual capacity relation between'said cooperating sets, of stator and rotor plates and auxihary variable capacity means disposed substantiall at right angles with respect tothe plane of said rotor and stator plates and electrlcally connected between each of said A cooperating sets of rotor and stator plates,

arranged to 'be independently actuated for compensating for differences in th capacity relation between said cooperating sets of plates.

3. A variable condenser construction comprisin in combinationa rotatable member, a set 0 rotor plates carried by said member, a cooperating set of statorplates with which said rotordp ates are arranged to be'interleaved, sai rotatable member having a pair of inwardly extending end plates forming bearing surfaces, and a journal comprising a stub member extending outwardly from a panel forengaging; said bearing surfaces whereby said rotatable member may be moved about said journal as a center for adjusting the mutual capacity relation between sa d rotor and stator plates.

4. A variable condenser construction comprising in combination a rotatable member, a set of rotor plates carried by said member, a cooperating said rotor p ates are arranged to be interleaved, and a journal for said rotatable member consisting of a stub member projecting outwardly from a panel, said rotatable member having a pair of inwardly extending bearing surfaces at opposite ends thereof arranged to engage said stub memberv and forming a housing for lubricant. therebetween, whereby said rotatable member may be readily revolved for interleaving said rotor plates with said stator plates in varyi g e a 3 5. A variable condenser constructioncom- 7 rising in combination a panel, a stub memr projecting outwardly from said panel, a

rotatab e member arranged to be journaled' on said stub member, a plurality of rotor. plates carried by said rotatable member and adapted to be interleaved witha plurality of stator plates, said rotatable member having a housin formed between a pair of end plates, said end plates projecting inwardly to form bearing surfaces for engaging said stub member for enclosing within said rotatable member a lubricating chamber where by said rotor plates may be angularly moved with respect to said stator plates with minimum friction.

6. A variable condenser construction comprising in combination with a panel, a stub member projecting from said panel, a rotatable member journaled upon said stub'member and carrying a plurality of tlpotor plates thereon, a plurality of statorfplates with which said rotor plates are arranged to interleave, a gear formed on one end of said setof stator plates with which rotatable member, an actuating shaft journaled in said panel, a pinion on one end of said actuating shaft arranged to mesh with said gear, and means interposed between said actuating shaft and said panel whereby said actuating shaft is free to move within given limits in a plane passing through said stub member.

7. A variable condenser construction, the combination of a panel, a stub member proecting from said panel, a rotatable member journaled upon said stub member, a plurality of rotor plates carried by said rotatablemember and arranged to be interleaved with a plurality of cooperating stator plates, a gear carried by said rotatable member, and a rotary actuator paming through said panel and having a pinion ad- 'adjacent one end thereof meshing with said gear, said rotary actuator having means whereby said pinion is normally spring pressed intoengagement with said ear and arranged to be angularly moved wit respect thereto in the plane of said. stub'member for compensating for irregularities in movement rotatable member mounted adjacent said panel, a plurality of rotor plates carried by said rotatable member, a plurality of stator plates insulatingly supported with respect to said rotor plates in such manner that said rotor-plates may be interleaved with said stator plates, a plate member substantially closing the rear of said stator plates and an auxiliary plate member mounted upon said supporting panel adjacent said first mentioned plate, and means for varying the spacial relation between said plates members for independently compensating for differences in capadit variation-between said stator and rotor ates.

9. A variabl; condenser construction com prising in combination a plurality of sets of stator and rotor plates arranged in the same plane .and adapted to be interleaved with each other for varying the mutual capacity, a substantially flat condenser plate secured to said stator plates and bending substantially at right angles to the plane of said plates on one side of said plates away from that side at which said rotor plates enter said stator plates and a resilient auxilaforementioned plate and adapted to be varied in spacial relation with respect thereto.

10. A variable condenser construction comprising in'oombination a rotatable meniber, a plurality of rotor lates carried by said rotatable member, a p urality of stator plates into which said rotor plates are arran ed to. be interleaved, a gear carried by sa'i rotatable member. a panel, a stub memher projecting from said panel upon which said rotatable member is 'ournaled, a rotary shaft actuator passing t rough said panel and car ing a pinion meshmg with said 5 gear, an a driven shaft passing through said panel said driven sha'lh'carr ing a 1'0- tai indicator and a pinion mes g with sai gear, said shafts having means for constantly urging said pinions into meshing with said gear, while allowing said inions 1 to move in a plane passing through t e axis of said rotatable member and compensatin for any irregularities in movement of sai gears.

FRANK O; HARTMAN.

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