US2496457A - Control mechanism - Google Patents

Description

Feb. 7, 1950 H. F. ELLIOTT 2,496,457

CONTROL MECHANISM Original Filed Deo. 24. 1941 5 Sheets-Sheet l Feb. 7, 1950 H. F. ELLIOTT 2,495,457

CONTROL MECHANISM Original FiledDeo. 24, 1941 5 Sheets-Sheet 2 oFF H i fm foo i? 115i M' y ggf/Q w] /5/ 1;?

Feb. 7, 1950 H. F. ELLIOTT 2,496,457

CONTROL MECHANISM Original Filed Dec. 24, 1941 5 Sheets-Sheet 5 fafa l IK f f1 mi!! if ji IZ] 15%,- 1139 I l l d (fy/ Feb. 7,1950 H. F. ELLIOTT 2,496,457'V CONTROL MECHANISM 5 Sheets-Sheet 4 Original Filed Dec. 24, 1941 y u a wmf/UWM @M Feb 7, 1950 H. F. ELITIOTT 496,457

l CONTROL MECHANISM Original Filed Deo. 24, 1941 5 Sheets-Sheet 5 I@ 25e/afan' f5@ n I MUTE Haya/d //a// 1.- f5@ j A Patented Feb. 7, 1950 UNITED STATES PATENT OlF-ICI?.v

Continuation ofapplication Serial No. 424,234, December 24, 1941. This applicationiledfAw gusti?, .1946,.SerialzNo. 688,920

(Cl. milf- 142) 22 Claims. 1e

This invention relates-generally toI mechanism for determinin-gk at predeterminedfcontrol position for controllable apparatus.y andiin-y particular to radio control mechanism. adapted for selective actuation. to: accomplish a AL ired'etermined tuning position forradio1'tuningfapparatus. This `application is a continuationv of applicationserial No. 424,234, led December. 24;, 1941, now abandoned.

It is an: object of' thisinventionto provide improved mechanisrrrfor.y den-ingra predetermined control position for controllable' apparatus.

A further objectief this-invention is to provide' improved.` control:` mechanism for. Aradio tuning apparatus'.

Another object of' thisrinventioni is:v to provide mecl'ianismj for reversiblel controllable apparatus capable of 'movingthexcontrollable apparatus in either direction. of. movement toa predetermined control position.

Yet another objecty of this-l. invention is to. provide` a rotary control? uniti for controllable apparatus adapted forassembly axially of its axis of rotationand including lost-motion means of a construction^ such. thatla :pluralityof the: control units can he stacked? in axial alignment in a Very minimum of space.

A still further objectief-this invention is tov pro; vide a control unitfontunin'g apparatus including gear elements operatingrwith higligeary ratios so that inaccuracies in rtuning are appreciahly decreased when transmitted' to` the tuning apparatus to accomplish accuratey tuning iny a commercially practical device;

A further 'object' of this invention isto provide control mechanism forr accomplishing a predetermined rotationof a rotary structure to a stop position.

Another object of' this invention is to-provider rotary control' mechanism for rotatable controllable apparatus' which i'scapable of accurately and. precisely stopping the apparatus at any one oi a plurality of rpositionswithin an operating range of any desired number'of revolutions;v thus providing great flexibility in both the designv of the control mechanism andthe controllable apparatus.

Still another object ofthis invention is to provide rotary control' mechanism adapted for operation in. two directionsofrotation from a uni-- directional motor. to a. predetermined control position. y

A particular featurevoi 'this invention is found` in the provision ora/.control unit which. is pre.- cision operatingy and yetA comprisedV of stamped 2. or like easily worked` partsto provide an inexpensive andv sturdy structure.

Yet another feature of this invention is found in the. provisionA of a. tuning unit having a plurality of control unitsaxiallyaligned on a rotary control shaitand operating individually thereon tor rotate; the` shaft: to, predetermined control positions. Each` control-unit includes a member adjustably supported on the. control shaft, with one of the control` units being adapted to coact withY manually operated means for clamping the adjustable members in Iadjusted positionsi Further objects, features,y and advantages vof this invention will. become apparent from the following description when taken in connection with they accompanying drawings in which:

Fig. 1, is a plan view of a radiol tuning unit embodying one` formy of. the improved control mechanism. of. this invention;

Fig. 2 is anelevational view of theunity inFig. l as seenfalongtheline 2-2in Fig. 1; showing the. relative arrangement of; the various rparts of the control mechanism and the. axial aligning of the tuning control units;

Fig. 3. is. a diagrammaticy illustration of. the control mechanism. showing, its operative connection4 with. the.` tuning means and the driving motor for the tuningapparatus;

Fig. 4 is. a-fragmentary sectional view taken alongthe line 4f--4 in Fig.. 2 showingv a portion of themeans. for. clampingthecontrol units. in their axially stacked relation;

Fig. 5v is .a View partly in section taken approximately along theline 5.-5,in.Fig.2;

Fig. 5a. is a fragmentary` sectional view as` seen along the line 5a,5a, inFi'g.y 2`;

Fig. 6 is an enlargedsectional detail view as seen along the line 6`6 in Fig. 5 showing a completecontrol unit and the stack clamping means;

Fig. 7 is a fragmentary sectional view taken along the line rl--l in.Fig..6 showing the lost motion or idler meansv for a control unit;

Fig.,8 is an. enlarged sectional view taken along theline. S-Bin Fig. y7.;

Fig..9.V is a fragmentary sectional view of a modied form of the lostV motion. driving and stop meansior a control. unit.;

Fig. l0. is. a sectionalfview takenonline Ill-l0- inFig. 9;

Fig. ll is a. sectional fragmentary plan kview showing a-tuning unit-y havingafmodied form of clamping. meansfor the` control units;

Fig. l2 isa transverse view through thel unit ofy Fig. ll showing a modified form. of driving means-for the control units Fig. 13 is a fragmentary bottom View as seen along the line I 3-I 3 of Fig. 12;

Fig. 14 is a diagrammatic control circuit for the tuning units of Figs. 1 and 11;

Fig. 15 is a plan view of a modified form of the invention;

Fig. 16 is an elevational view as seen along the line I6|6 in Fig. 15;

Fig. 17 is a fragmentary sectional View as seen along the line |1-I1 in Fig. 15;

Fig. 18 is a View illustrated similarly to Fig. 17 showing the parts thereof in changed positions;

Fig. 19 is a fragmentary detailed sectional view taken approximately along the line I9-l9 in Fig. 18;

Fig. 20 illustrates diagrammatically a control circuit for the modified embodiment of the invention shown in Fig. 15;

Fig. 21 is a fragmentary sectional view partly in section illustrating a centrifugal switch for optrollable apparatus in either direction of rotation :.5

to a predetermined control position. The control mechanism utilizes rotatable operating elements constructed and assembled to provide for multirevolution lost motion within the mechanism to permit the use of a plurality of control units within the mechanism without mutual interference. This lost motion, which occurs entirely in the control mechanism, permits a high gear ratio within a very small space between the controllable apparatus and the control mechanism. Inaccuracies in obtaining predetermined control positions of the controllable apparatus are thus made very small because of the Vernier action of the control mechanism. This feature of the improved control mechanism provides for great flexibility in its design as well as in the design of the apparatus to be controlled. Also it makes the control mechanism very desirable for application to radio tuning units, with which it is illustrated in the drawings. It is to be understood, however, that its use is not to be so limited and that it may be applied to any controllable apparatus. By changing the relative rotation of parts thereof the control mechanism or unit is also capable of accomplishing a predetermined angular rotation of a rotary structure before locking the structure in a predetermined stop position.

As illustrated, each control unit consists of axially spaced rotary gear members supported for relative reversible rotation on their axes, and lost-motion means including an adjustable member intermediate the gear members and operatively connected with rotary gear means mounted on each gear member. On reversed rotation of the gear members the rotary gear means are successively locked with opposite portions of the adjustable member to in turn lock the gear members against relative rotation to define the predetermined position of the control apparatus, with the initial direction of rotation of the axis to such control position being determined by the direction of rotation of the rotary gear member initially overtaking the adjustable member. The gear ratio between the rotary means and the adjustable member may be any desired value so that the extent of lost motion in a control unit may be set at any predetermined value by merely changing the gear tooth size on the adjustable member and rotary means. The rotary means carried on a corresponding gear member are radially spaced from a corresponding adjustable member so that the space occupied by each control unit in a direction axially of the control shaft is very small. A relatively large number of the control units can thus be stacked within a relatively short space to provide maximum control within a compact mechanism.

Referring to the drawings, the improved control mechanism of this invention is illustrated in Figs. 1, 2, and 5 as applied to a radio preselector or tuning unit including a frame means 25 comprising a channel or U-shaped member 26 having inwardly bent flange portions 21 at each end 28 and 29 thereof. The ends 28 and 29 are closed by end plate members 3l and 31a, respectively, extended transversely of the frame member 26 and positioned inwardly of the corresponding flange portions 21 at the ends 28 and 29. The plate members 3l and 31a are rigidly secured to their corresponding flange portions 21 by welding or suitable like means, so that the assembly of the members 3l and 31a with the frame member 26 is of a substantially integral construction.

A unidirectional driving motor 32 is mounted on the outside of the end plate 31a by supporting studs 33 extended through the laminated motor eld structure 34. The motor shaft 36 is rotatably supported in strap or bearing members 31 secured to the field structure 34 by screws or the like 38. A pinion 39 (Figs. 1 and 21) is secured to the motor shaft 36 and is held in frictional engagement with the motor armature 4U by a spring washer 40a and collar 40h. Pinion 39 is in meshing engagement with a gear 4l mounted on a rotary driving shaft 42 which is rotatably supported in the end plates 3| and 31a. The gear 4| is in driving connection with the shaft 42 through flexible connecting means designated generally as 43 and including a driving spring 44. A centrifugal switch mechanism designated generally as 45 may be mounted on the outer end 36a of the motor shaft 36 for operating muting means and remote control button interlock and release means (Fig. 22) which will be hereinafter fully described.

The driving shaft 42 (Figs. 1 and 5) is formed with an axially extending spline or groove 46 for receiving in mating engagement corresponding key portions 41 on a driving gear 48. A crank arm 49 is rotatably supported on the shaft 42 and positioned adjacent a gear 48 with each paired gear 48 and crank arm 49 being spaced axially of the driving shaft 42 by spacer members or collars 5l Thus the shaft 42 is rotatable relative to the arms 49. A corresponding gear and crank arm 49 are operatively associated with a corresponding control unit, which is designated generally as 52 (Fig. 2).

Each gear 48 is in continuous meshing engagement with a power-transmitting gear 53 (Fig. 5) which is rotatably supported at the end 54 of the crank arm 49, the gear 53 in turn being adapted for meshing engagement with a pinion 56 rotatably supported on a shaft 51. There is a gear 56 corresponding to each control unit 52 (Figs. 2 and 6), the gears 56 being spaced axially of the shaft 51 by spacer portions 58 integral therewith. A gear 53 is moved into meshing engagement with a corresponding gear 56, to operatively connect a control unit selectedl forfoperation-With the driving shaft 42g by pivotal movement-*of the cranllz arm 49 by means includingan actuating magnet 59; From a considerationof Figs.- 1' and 5, it isf seen that the magnets 59 are extended transversely of the driving' shaft 42 and' positioned so as to attract thereto the end* Bl? ofi a corresponding crank arm 49:- On attraction` of the cranky arm 6i' inv closingl positionVVK with a corresponding magnet, aswill be later described', the

arm end 54-y is pivotallym'oved an amountsuflicientl to provide for the complete meshing-- engagement-'of l the gear 53 with ar corresponding pinion 5t;` When the magnet 59"is deenergized the crank arm 49 is' pivotally moved to' arest position against a stop member 64 by a-coilspring 621 connected at one end to a tie rod 6?.'4 and its opposite end to the cranlr arm end'l. The driving spring 44 of A"the flexible connecting means 43l provides a s'mallreverserotation'tothe motor shaft 3'6v after the magnet-Ellis deenergized to assure a positive disengagement of' the gears 53-56.

Eachpinion liliigs.' 2; 3,'a`ndf5) is in continuous meshing engagement with a rotary gear inemberr and? a pinion 61. There is a pinion G1 corresponding to'each control unit 52, the pinions (i1vv being rotatably supported' on a shaft 68`-` in spacedlaxial alignment byy spaceror collarmembers 69. Each control-unit 52 includes apair of similar gear members 66 and 65a, with a gear 66a; being in continuous'fmeshing engagementwi-th a corresponding pinion 61." Since each control unit 52 is of asimilar' construction, only one thereof willbe referred to inv the' following description.

Thecontrol units 52` arer` aligned axially of a rotary control shaft 1l (Figs. 2 and 5) having a gear 1'2 `mounted at one end thereof, in continuous meshing engagement with a split spring tensioned g'ear1iv mounted on a shaft 14`f for tuning means FSlillus'trated as of gang condenser type. It isfto be understood', however, that the improved controlunits 52 ofthis invention are also applicable for use with other type tuning means. The control shaft1l and the condenser shaft 14are suitably mounted in the end plates 3l andy 31a 'preferablyv Ion ball bearings or yother bearingsl having no los'tmotion.v It is evident,` therefore, that the condenser tuning means 1.6v isyin driven connection! with the eontrolshaft 1I for rotationl in either direction by means including spring'tensioned bearings and gears,s'o that rotation ofthe control shaft 1-`I to apredetermined control position in turn accurately rotates-the condenser 16 to a corresponding predetermined tuning position.4 From the above descriptionL and consideration of Figs. l, 2,r 5, ando', itis -evident that all of the'rv axes means 42, 51, 68,.1|', and 14 supporting the control mechanism are extended in parallel alignment longitudinally of the frame means 2,5f'and operatively carried in the end plates 3| and 3 lai,V withthe elements carried ony corresponding ones of the above-defined' axes means being confined entirely within the frame means 25. The relative parallely alignment ofthe yshafts 51',` 68, andi1| is assured over all axial portions thereofat alltimes of operationv by a retaining or'spacing plate y (Fig. 5a) common to such three shaftsuand supported thereon intermediate their ends.. The tuning unit isthus assembled 'as' a very rigid: and compact structure, withy the frame means therefor being/capable of absorbing high stresses without permanent distortionas occurs withY the conventionalstaked or' riveted frames now Widely used.l

As previously mentioned; each: controla uniti 52 includes a; pair of rotary gearsf 6'6 andi: 66w.wliic`h are spaced axiallyfof' the contr-olf: shaft! 1li and operatively jassembled with:- a: correspending.` adj-ustablegear member' 11 (Fig-s.. 6 to: 8). The adjustable member 1111 is freely riotatablerandislidable on the control shaft 11| which, as; shownfin Fig. 1, isi-formed"r with apair ofi oppo'sitely' positioned flatfsides 18 Thehub 19 fortlie adjustable member 1'1'is provided'. with end portions. tllfv and 8150; of'a'reduce'd diameter for rotatably supporting at eachk end a correspondingonefof the'.v gear members 66 andi 66a. The-periphery of: the` hub lf''intermedi'ate the end portions? Stand-81a is formedwithfgear teeth 811i' with" a toothzindicate'd as 'beingi'extended axially in. both directions bey'ond'the remaining teeth'i'.

Each rotary gear membery Galand; EGa'rhas: rotatably supported thereon afcorre'sp'ondinglrotary gear or' idler means 86. andapositioned. inwardly of thegear' members.` islcl'earlyfsnown in Fig; '7, for the ygear-z 661 the rotarymeansl 8Gk is radiallyspacedi fromithe' adjustable member 1%1', with a rotary gear portion .815' thereofy in continuous meshingengagement with; theteetlifsoon the adjustabley member formain'ta'in-ing 'a 4predeterniinedl operating relationship in:y a lost-motion means to ber later explained;` It is` to be1under= stood', of coursey that the krotary gear i means 86u 'is similarly operatively-1 connected* witlfiv the/'sad'- just'able member 11'. Since ktliisoperative:connecL tion' with theadjustable member lTisi-thesame for each of the rotarylmeansfandi 86a, onlythe rotary meansftii` willlbef' referredftoin the detailed description of these'parts;

Referring to Figs.y '1T' and 8, the'rotary-gearpore tionflll. is seen-to be rotatably supportedon arlifet or axis means 88 extended thronghland secured to the gear 6G; The rotary gear-'portion ail' is operatively connectedv with1 a'fflocking portion'`v 89 comprising l'al discv rotatable with the.` gear'po'rtion 81 and' having a stopf9ll exten-dingtradilally-betweenE apair'ofadjacent teethV onf-thegear portion` 81; The locking portion', B9 is positioned be.` tween the gear portionI 81 and; tl'ie rotary gear 646-' so as to be radially spaced'v out of an engaging position with the# teeth 80": on' the" adjustable member 11 (Fig 8). However, since'` the lone toothl 80" extends substantially between the gears 66 and 66a; eachI end l thereof is' inf a radially spaced` relationwith a corresponding'locking por-y tion 89-and89'a.y Relativerot'ation or lostfmotion between therotarygear portion' 8`1' and the adjustable member 11"thusr' takes place only so long!1 asvthe-st'op 97| doesf not engage-the' stopor long tooth- 80 onthe' adjustablemember. When the stop 9| engages the-stop *8051 the-gear'l i's' locked in ar-flxed position relatilvetof-the adjustable member 11 so that the two mayf'rotate to'- gether. l

The l'os't'motion occurring in the-controlunit {i2-'prior to a lockingfof thegearsiand 66a with the adjustable member 11"may befestablislied at any desired ramount by merely changing-fthegear ratio betweenl the idler'4 geari B6`i andthe ladjusi'fable member TLT As illustrated in Figs; 7,* the idler gear 86. is shown with I3 teeth,lwl-illethe-adjustable'r memberv 11is shown-'Within teeth.l With' the stopy portion ilil inan engaged position withy one' side the s topi'portionkk 8U on the' adjustable-mem'- ber '11,' the adjustable member 11f'can' be rotated twelve and afraction complete revolutions in a direction outfof'such locking' position before' the stop 9|g willagain engagetli'e 'stop-80"" onI` the oppositesdethereofl f f il! It is seen, therefore, that the improved control mechanism of this invention is comprised of a determined number of rotatable operating elements, relatively assembled so as to occupy a space axially of the control shaft 1| substantially equal only to the axial length of an adjustable member 11. In one commercial embodiment, the overall length of the adjustable member is 1A" and the diameter of gears 66 and 66a is 1%. The control unit is thus compact in every direction, with its dimensions remaining unchanged over wide variations in the gear ratio between the idler gears 86 and adjustable member 11.

In the stacking of the control units 52 axially of the control shaft 1|, each control unit 52 is separated from a next adjacent control unit by a washer or separating collar 82 having iiat sides 83 for mating engagement with the lat sides 18 on the rotary control shaft 1| so as to 'be held against rotation relative to the shaft (Fig. 6). As noted, each of the reduced hub portions 8| and 8|a are of an axial length greater than the thickness of a corresponding rotary gear 66 and 66a. Thus with the control units 52 axially stacked on the rotary control shaft 1|, and in a spaced relation by virtue of the spacing washers 82, on their being clamped together as by lclamping means designated generally as 84 (Figs. 2 and 6), the adjustable members 11 are frictionally locked between adjacent ones of the spacing washers 82 so as to be rotatable with the washers 82 and the shaft 1| as an integral unit. However, since the axial length of a reduced hub portion at each end of the adjustable member 11 is greater than the thickness of a corresponding rotary gear 66 and 66a, such gears are freely rotatable on the adjustable member for rotation relative thereto and to each other.

In the operation of a control unit 52 let it be assumed that the adjustable member 11 is in an adjusted position corresponding to a predetermined control position of the shaft 1| and, in turn, to a corresponding predetermined tuning position of the tuning means 16. This operation is best understood from Fig. 3 in conjunction with Fig. 7. As previously mentioned, the motor 32 is of unidirectional type and for the purposes of explanation let it be assumed that its rotation is in the counter-clockwise direction indicated by the arrow in Fig. 3. This direction of rotation in turn rotates the pinion 39 on the motor shaft 36 in a counter-clockwise direction and the gear 4| in a clockwise direction. With the gear 4| thus rotated, the driving shaft 42 and hence each driving gear 48 are also rotated in clockwise directions. Because of the continuous meshed engagement of a gear 48 with a power-transmitting gear 53, the latter is rotated in a counter-clockwise direction.

On pivotal movement of the crank arm by the magnet 59, as will be later fully explained, the gear 53 is moved from its full line position to the dotted line position shown in Fig. 3 in engagement with the pinion 56. This engagement rotates the pinion 56 in a clockwise direction to in turn drive the pinion 61 and gear 66, which are in continuous engagement with the pinion 56, in counter-clockwise directions. Since the pinion 61 is in continuous meshing engagement with the gear 66a, this gear is rotated in a clockwise direction or oppositely to the direction of rotation of the gear 66 in a corresponding control unit 52. By virtue of this reversed rotation of the gear members 66 and 66a their corresponding idler gears 86 and 86a, respectively, are reversely rotated in opposite directions about the adjustable member 11 as indicated by arrows in Fig. 3. It is apparent that with the shaft 1|, and hence the adjustable member 11 in a stationary position, that rotation of the idler gears is accomplished by their being rotated about the adjustable member by the gears 66 and 66a.

Because of the rotating lost-motion action of the idler members 86 and 86a relative to the adjustable member 11 the control shaft 1I, and hence the tuning means 16, remain stationary until one of the gears 66 and 66a is locked with the adjustable member 11. Thus let it be assumed that the gear member 66 is initially locked with the adjustable member 11 in the manner above fully explained in connection with Fig. 8. When this locking occurs, lost motion between the idler gear 86 and member 11 is discontinued and the adjustable member and hence the control shaft 1| are rotated in a counter-clockwise direction corresponding to the direction of rotation of the gear member 66 as indicated in Fig. 3. Because of the reversed rotation of the gears 66 and 66a this rotation of the adjustable member 11 by the gear 66 accelerates the relative movement between the idler 66a and the adjustable member 11 to in turn accelerate the occurrence of the looking action between the adjustable member 11 and the gear 66a. Since the idler gears 86 and 86a are rotated in opposite directions relative to each other, and reversely about the adjustable member 11, the corresponding stop portions 9| and Sla thereof engage opposite ends and sides of the stop portion or long tooth 80' on the adjustable member. Since the driving force of the gears 66 and 66a acts on the tooth 80 in opposite directions, and since these opposed forces are equal, the coupled engagement of both gears with the member 11 locks such gears against further relative rotation to deiine the predetermined control position of the shaft 1|. It is obvious, of course, that if the gear 66a is initially locked with the adjustable member 11 that rotation of the control shaft 1| will be in a direction corresponding to the direction of rotation of the gear 66a, or in a clockwise direction as indicated in Fig. 3, which rotation will continue until the gear 66 is also locked with the adjustable member 11. Because of the continuous meshing engagement of the adjustable member 11 with each of the idler gears 86 and 86a, a predetermined operating relationship is continuously retained between these three elements. Although the rotation of the motor 32 is unidirectional, the opposite rotation of the gears 66 and 66a provides for a rotation of the control shaft, and hence of the condenser 16, in either direction of rotation to a predetermined tuning position.

It is obvious, of course, that with a control unit in a locked condition resulting from one direction of rotation of the shaft 1|, that rotation of the shaft may take place in an opposite direction to a degree corresponding to the lost motion in the control unit, until locking of the control unit is again accomplished. This establishing of a known lost motion may be used where it is desired to rotate the apparatus to be controlled through a predetermined angular distance prior to locking it in a stop position. A plurality of control units may thus be stacked on a single shaft without mutual interference, while permitting manual rotation of the shaft without requiring any disengagement of the control units.

A modied form of lost-motion means for a cootroiumt 52 is shown ,in rigs. si-,and 1o. The

adjustable element 11 .isormed with reduced end Lportions .9 3 and 93a capable `of receiving thereon .gear elements j91! and 94a, respectively, for `rrotary ,gearsl ,and 66a,respectively. The gearelements 955 and llagare Yfixed.onthemember .'II' as `by a press ,tor A.the like so as to .be rotatable therewithasa unit. The axial extent of .each reduced hub portion 93 ,and 93a is such that on clamping of the :member 'I'I between the WashersZ the gears and .65a are freely rotatable. .The .portionof .the adjustable member 'I 'I between the ends S3 and 93a 'thereof is formed with a single radially vprojecting tooth vorstop portion .95 which extends axiallyoi the member Vl .between the gear elements 94 and 94a rand in vmating alignment .with .corresponding axially aligned .teeth on .the gear elements y911 and 94a. The elements `Sil and Maare incontinuousfmesm Ving engagement .with ,corresponding idler gears 92 `and .92s. Since the lost .motion vor coupling means .for eacllsear 56 and 66a is the same, only the meansior geari .Willbe referred to in `the detailed. description of these '.parts.

The `idler `gear 92 .is rotatably supported .on a pin .95` .mounted rin .the 4gear member .56, .the .gear 92 .being .positioned .adjacent the gear .66 and radially rspaced from the gear element .94 .for continuous meshing engagement therewith. An annularv portionlifl .concentric with and rotatable with ,the idlergear .92.is,`positioned about the `pin Q5 in radial .alignmentwith the stop or ytooth portion llt .on the adjustable member l1. ,The annular ring 91 is. integrally formed with a radially extending stop .portion 98 for .locking with the .tooth llili in a manner which is in all respects similar to the .locking action previously fully described in connection .with thestop 9| and the .adjustablemember .1.1 in Fig. .8. .Since rthe operation oi' .a controlunit With .the lost-.motion means ,of Figs. Sand '10` is .similar .in all ,respects to theioperation as described in connection .with the lost-motion means of Figs. 6 8, inclusive, a further .description thereof ,is believed .to be unnecessary. .For rapid .highspeed tuning itis desirable to have the .units .somewhat resilient, and specifically the gears andc capable rof springing, so as to absorb the shock tc the .unit resulting ,from the .impactwhich occurs .when rall stops in a unit are locked ,together at ythe predetermined control position. 'lhe .resiliency inherent in the units .as described can be increased by vusing ,a thin spring-tempered metal for .the gears bis and lita, .and .by .removing ,portions thereof, indicated at .99 in Fig. 1.0, at the point oijbcnding.

As previously mentioned, the adjustable .members 'H for the control units 52 .are held in their adjusted positionsby clamping means 84. The clamping means 84 (Figs.`.2 and 6) .are mounted on .the control shaft 'Il together with means for limiting vthe rotation of the control shaft and include a `pair ojf axially spaced gear merm,

bers 'IDI and Silla rotatably Supported on the shaft- :'Il but retained against rotation relative to the frame 25 'by the locked engagementof the teeththereon .with stop clips L02 removably attached tothe frame member 26 by screws |53. The member I 04 intermediate the gears illl and lla is .provided with iiat key portions m5 for mating v engagement with the fiat shaft sides "I8 Soas tobeslidablybut non-rotatably supported on the shaftII. Rotary means 86 yand 86a ,identical ,in all respects to the like means used in .thessntrol .units .5.21amn rotatably carried von corresponding. essi-members l0! and position. T o ,release A.the.-adjustable `members .1,1

for Aadjustment to :new positions y:the yshaft 51 is rotated in a direction itoiaccomplish such :release and, vin fturn, rrotates .the 'control shaft 'll @and hence the y member .404 through ,gears [0 8 and I,0'I. Since .the gear members .IDI `|and -I0I,aar e retained against frotation, `rotation of 1 the meme: ber `I-04 continues until yit is locked Withoneof thek idler means such as A86 itc imitianyf-turther,

rotation .of tlleshaft l-I. ,Howevenfon .continued rotation vof the Lshaft AS'I, .the (clamping -nut v.H16 is axially'threaded away from the .control units 52, or fto the right ias `.viewed inqfFigS. 2 and i6, until it engages the .-stop nut y.II0',.fscesito release the r`adjustable members 15|.y Some ,pressure .is continuedson the .adjustable members '1.1 and -nut |06 by a tension Washer Nil to -retain :them against free rotation, the Washer beingsupnorted on'the .shaft `1I betweenwashers -II Iaand -I\.I-.Ib,

with the three-Washer assembly in turn `,being intermediate the gear gmernber fI'0Ia land ther clamping nut |05. Since thefloclgedpositionof the fmember @104 :with each .of the rotar-y means 86 defines :the rotation of fthe shaft .11| .in reversed directions, :it is contemplated l`that this ,rotation be such as to -gpermit rotation of the condenser 1.6 throughoutacomplete 'tuning range. Thus, with the control units 52 rin -a released position, the manipulation of knob IIIQ 'rotates @thereondenser to any desired `tuning position. zlWithfthe knob I 09 held `manually .toretain such tuningpostion, the control unit corresponding f-to fthelselected tuning position is actuated :'byffpressingfifa button II-I to .energize va corresponding magnet 59 land the driving .motor 32,'as-.Willbe thereinafter describedin connection .with Fig. 14. "This rotates the rotary elements of the control unit l to a locked position deningthe adjusted position being retained by'virtue ofthe f rictional pressure thusset, the shaft 'ljsfrotatedin a directionfor.

clamping the control units. ,Thisrotation o f the shaft '51, in turn, rotates Athe control ,shaft 1,I

until. locking is .accomplished between lthe msm-k shaft end opposite thenut IllB for retaining the units 5 2. The tuning ,unit .is .thus `prepared for selectivetuning.

I nlFlgs. 11113, inclusive, thereisshwn A a radio tuning unit whichis .substantiauy similar insll respects to the tuning unit of Fig. 1 except for a modied form of driving means and clip arrangement for the stack clamping means for the control units 52. Thus, as shown in Fig. 12, the crank arms 49' are pivotally supported on the shaft 51 for the pinions 5B, it being understood, of course, that a crank arm 49 and pinion 56 are individual to each control unit 52. The powertransmitting gear 53 on the crank arm end 54 is in continuous meshing engagement with the corresponding pinion 56. When the control unit 52 is in an idle position the gear 53' is out of meshing engagement with the driving gear 48', which position is indicated in Fig. 12. As shown in Fig. 11, the driving gear 48 is a pinion of elongated construction common to all of the control units 52. On energization of an operating magnet 59 for a control unit 52, therefore, the armature end 6| of the crank arm 49' is moved in a clockwise direction, as viewed in Fig. 12, to in turn pivotally move the crank arm end 54', whereby the power-transmitting gear 53' is engaged with the driving pinion 48'. When this engagement occurs, the control unit 52 is operated as was fully described above. On opening of the circuit for the magnet 59, as will be later explained, the gear 53 is moved out of meshing engagement with the driving gear 48 by the ac tion of the spring 62'.

The clamping means 84' is similar in all respects to the clamping means 84 in Figs. 2 and 6 except that stop clip members ||2 are used in place of the stop clip members |02. The construction provides for a standardizing of the parts used in the control units, rotation limiting stop means and clamping means whereby to decrease the manufacturing costs for the overall unit. The gears and |0| a of the rotation limiting means are identical in all respects with the like gearsv 66 and 66a. of the control units 52, and although rotatably supported on the control shaft 1| are retained against rotation by the stop clips I l2 secured to a portion 26a of the frame member 26 and adapted to be inserted between adjacent teeth on the gears |0| and IUIa. Thus the gears IUI and |D|a may be easily and simply xed at any desired position to accomplish a predetermined rotation of the shaft 1| between the clamping and releasing positions of the clamping nut |06. Since the operation of the clamping means 84' is the same as that previously explained for the clamping means 84 in Fig. 6, a further description thereof is believed to be unnecessary. It is to be understood, of course, that a single gear member IUI or |0|a could be used with a corresponding idler or lost-motion means for satisfactory operation with a stack clamping means.

The tuning structures disclosed in Figs. 1 and 11 may be utilized in either A. C. or D. C. circuits. By way of explanation, an A. C. circuit for these structures is illustrated in Fig. 14. The magnets 59 are connected in parallel between conductors I|3 and I I4 which are connected with an A. C. supply such as the secondary 'winding |00 of a power transformer I I5 connected to a suitable source of supply |I6 such as a 110 volt A. C. line. The motor 32 for operating the control units 52 is connected in series with each of the magnets 59 so as to be energized concurrently on energization of each magnet. It is evident, therefore, that on closing of a push button I I1 the magnet 59 corresponding to the selected push button and the motor 32 are simultaneously energized. Thus, referring to 1, the rotary gears 48 are rotated simultaneously with the actuation of the power-transmitting means 49--53 into meshing engagement with a pinion 56, while the corresponding parts in Figs. 11 and 12 are the elongated pinion 48 and the power-transmitting means 49'-53', which is moved into meshing engagement with the Vpinion 48.

The radio oil switch or button IIB is operatively associated with a control unit 5'2 and a magnet 59 in all respects similar to the same parts operatively associated with each tuning button ||1. The magnet 59 ifor the off button ||8 is connected in parallel with the magnets 59 for the tuning buttons ||1 from the common conductor I I 3, through the button I I8, magnet 59, and conductor ||9, the normally closed contacts |2| and |22 of a gang switch |23, and conductors |24 and |26 to the common conductor ||4. The gang switch |23 also includes a contact |21 which is normally closed with the Contact I22 to operate the heater circuit designated generally as |28. Also included in the gang switch |23 are normally closed contacts |29, |3|, and |32 for a rectifying circuit |33. As best shown in Figs. 12 and 13, the contact arms of the gang switch |23 are suitably mounted at one of their corresponding ends by means designated generally as |36 to the bottom or connecting portion |31 of the U-shaped frame member 26, the arms of the contacts |29, |'2| and a spring arm |39 being arranged to operate in unison through a common insulated member I4|. On movement of the member I 4| toward the left as viewed in Fig. 14, or downwardly as viewed in Fig. 12, contacts |2|, |22, and |21 are all opened to in turn open the heater circuit |28 and the 01T control circuit. In like manner the contacts |29, |3I, and |32 are all opened at the same time to open the rectifying circuit |33.

In the operation of the control circuit of Fig. 14, let it be assumed that the tuning unit is in operation at some selected tuning position, which condition is illustrated in Fig. 14, and that it is desired to shut the radio off. On actuation of the 01T button I8, the control unit 52 corresponding thereto is operated to move the condenser 16 to a predetermined control position at one of the extreme limits of its rotation. As shown in Figs. 1 and 12, the condenser shaft 14 has an actuating arm |34 mounted thereon for actuating the gang switch |23. On rotation of the condenser 16 to an extreme clockwise limit, as viewed in Fig. 14, the arm |34 engages a cam follower portion |42 carried by the spring arm |33 to move the member 4| to operate the switch |23 as above described. When the switch has been opened, the off control circuit is opened so that further actuation of the button ||8 is ineffective to energize the magnet 59 corresponding thereto and the radio continues to be shut off until a station tuning button |I1 is actuated.

Since the circuit for the magnets 59 and motor 32 is capable of being operated, even when the radio is shut oi, a subsequent operation of any one of the tuning buttons I1 `provides for a rotation of the condenser 16 out of its extreme position defined by the off button ||8. Immediately on its rotation from such extreme position the gang switch |23 is permitted to operate to close the heating and rectifying circuits of the radio. It is evident, therefore, that any one of the tuning buttons |1 automatically turns on the radio set While providing for its operation at a predetermined tuning position corresponding to the tuning button ||1.

In Figs. 15-20, inclusive, there is shown a modication of the invention which is similar in many respects to the embodiment in Fig. l. fSimilar numerals lof reference, therefore, will be used to designate corresponding parts.

The driving motor l:32 is in driving engagement with the =pinionassembly 56-6`|, through thepinion '39fon the motor shaft36 and the geary 4|, the gears 48a (inthe-rotary drive shaft 42a being connected'with'corresponding pinions 56 Aand 5l for a control unit 52a. The'power-transrnitting gear 53 is rotatably supported on the crankarm 49a, which inturn is pivoted on the driving shaft 42a. The shaft 42a (Figs. `1'7 and'lS) yis formed with opposed zfiat portions |52 for keyed engagement with the-gears 48m-mounted on the shaft42a and internally formed with mating iiat portions,there being a lgear ||8a foreach control unit'52a. The crank arms 49a vare rotatably supported on the shaft `42a and arranged 4between adjacent ones of the gears 48a. Each gear 48a is in continuous meshing engagement with lthe power-transmitting gear 53 which is freely rotatable on the armature end 6|a of a crank arm 4911.

The armature `6Ia is attractable by a magnet 9, the mag-nets being vertically `arranged inthe unit as lshown in Figs. 17 and 18. The actionof magnet 59 on its corresponding armature v6|0L is opposed by the action of ya spring |5| which is connected at yone end to a lprojection |53 on the crankarm `|l9a ,and Iat its opposite end to a tie rod or rail Ell-carriedin the tuner frame means. The armature v6|a is fheld in an open position against 'a non-magnetic rest-rail |56 by the spring I5I. Abrass 4stop or magnetic separator S is secured to the armature 6|a in arposition such that it `engages the core of the magnet 59 when the armature is attracted thereto, so as toeliminate any possibility of lthe armature `freezing 'to the magnet.

Thepinions 56 Aand 51 are'engageable with the gears 6.6 yand 66a, '-respectively, of a control unit 52a. Besides'the gears 66 and'66a each unit52a includes :an adjustable collar lmember 11a, with adjacent'units'52a being spaced from each other by spacing washers "82a. The flat portions 'I8 formed on the shaft 1| are adapted 'for keyed engagement with corresponding iiat portions formed ,internally of the spacers 82a. The adjustable member 11a is formed with a reduced section |51 and `|`5`|a at Qpposite .ends thereof adapted to`havea corresponding gear k(i6 and 66a freely rotatablethereon. In the assembly of each control unit 52d the adjustable collar member 'Vla with corresponding gears '66 and 66a thereon are alternately `stacked with'the spacing washers 82a on the .control shaft '1|. 'Since the rnounting portioncn'eachmember 1`|`|a for the gears Y66 and 66a isof an axial length greater than the thickness of suchjgears, `the pressing togetherof the control `units vduring their assembly on the control shaft ,1| doesnot bindthe gears and 66a relative to the shaft 1| but serves merely to ricti'onally 'lock the adjustable members 11a between each'adjacent pair ofspacer members 82a. The frictionalengagement of ythe members 11a in particular adjusted positions corresponding to predetermined control 'positions of the shaft l 'is obtained rby the manipulation of suitable .Stack clamping mechanism designatedgenerallyas 58.

The adjustable'collar member 11a for each controlunit 52a Iisformed with a radially proj e'cting but axially extending abutmentba of rounded gear tooth contour. Thisabutment'is'formed and arranged for engagement-with `pinions |155 and |159a'which are rotatably supported on pins |6| and |6|a mounted in 'theiface hportion of "gea-rs I4 66 and:66a;respectively. vIn Lthe assembly fof reach gear |59 and |59a'a spring washer |62,.-asfshoW-n forthe gear :I 59 .inFig '19,'is positionedabout the pin |6| between the kgear |59 `and the pin head |63 ito effect a slight drag or frictonal'pressure on the gear. Thispressure is just enough tofpre- Vent the Agear |59 from :moving out of` a .predetermined meshing position with the abutment f 80a duringrotation of the-gear 66. The toothed `contour of each of the gears |59 and |59a is formed with a lblank portion .|64 (Fig. l18) which isrsubstantially requal to the width of twogear teeth. With vthe adjustable 'collar member .'Ha :fixed relative to fthe rotary control shaft 1|, and :the shaft 111| in 'a stationary position, lit isfseen'rthat eachco-mplete vrotation ofgear F66, .as shown in Figs. y17'? and 18, rotatesthe gear :|59 va distance equal tofone tooth-because of itsengaigement with theprojection Bilal onithe member 11a. '.Thezprogressive rotation vof the gear |59 about'the .pin lr6! continues Auntil the portion '|564 :engage-s zthe tooth or abutmentfa, ,this coupledfengagement serving -tolock the membenllaandvthegeari in fixed positions relative to the shaft 1| sothat any further rotationy of :the ,gear 166 Valso rotates the shaft 'With the pinions 56 and 61 in continuous engagement with` each other andiarrangedito yrotate the gears 66 `and ,66a in .opposite .'directions,r the blank portions |64 on the idler .'gears |59 l'and |59a will 4engage oppositesidesor vportions 'of the tooth lilla. A. lockedfengagement, ,of each-gear |59 Iand 39a with fthe tootha locks the :gears 66 and 66a relative to the controlishaft :"|I ,ithis locked -`engagementdeninga predetermined control position of the shaft 211. The-gearsforl'a first connectedfin a coupled engagement withfthe adjustable member v'lla'byf the locking action of its associated idler rgear with the tooth lilaserves to rotatethe shaft 1| in a given direction until a position is reached whi-chvbrings about the coupled connection betweenthe member 11a and the uncoupled gear, thuslockingfboth :gears 66 and GSC/against anyffurther rotation to define apredetermined `control position. Theadjustment of the members'lla to a desired setting of the control shaft 1| isobtained yin a manner similar to that preViouslydescr-ibed for the members in Fig. l, the vfrictional locking of the members'l'la being accomplished -by the clamping mechanism |58.

Although the idler gears |59 and |59a are indicated as providing for a relative rotational movement o'f something -over l2 revolutions between yeach of the gears y66 -and166a and member 17a, `rtocorrespond with a desired 12:1 driving ratio between the control shaft 1| and condenser !16, it is to be understood that the Agears 66 4and 66a vand the pinions |59 and 4|5911 can be altered in size and in 'the number of teeth thereon toprovide `for a wide variationin the free or lost motion .cfa control yunit52a. This lvariationvinthelost motion of lthe control mechanism provides for a corresponding variation vin the useful operating frange of the controlshaft "H,

such range vwiththe Aabove 12:1 ratio being vapproximately 6.4revolutions.

The 4structure of each control unit `52a thus providesfor a'high4 driving ratio between-the control shaft 1| and the condenser'l without'increasing the v'bullt'of the tuning `device regardless of 'the driving-ratio obtained. A very compact, precise .and "highly eflicient ytuning yapparatus ris thus provided which :is 'readily applicable Ato fa varietyfoftuning requirements.

A control circuit for the embodiment of Figs. 15-19, inclusive, is shown in Fig. 20. Although this control circuit is illustrated as being operated from a source of D. C. it is to be understood that the tuning structure of Fig. 15 may be operated equally well on A. C. In the latter case, a suitable A. C. motor is utilized, and with the nonmagnetic spacer S being preferably made from a material such as neoprene or a tough fibrous vellum.

With reference to Fig. 20, on energization of a magnet 59 by a push button |66, the motor 32 is simultaneously energized through the double set of contacts |61 and |68 whereby the drive shaft 42a with the rotary gears 48a thereon is rotated substantially simultaneously with the actuation of the power-transmitting means 49a-53. That is, upon pushing a button |66, the corresponding magnet 59 is iirst energized by engagement of. the button contact |65 with the battery contact |68. Continued pressure upon the button brings the contact |88 into engagement with the motor contact |61, the contacts |68 being in a common circuit.

The rotary gears 48a are engaged to rotate in a counter-clockwise direction, as viewed in Figs. 17 and 18, to rotate gear 53 in a clockwise direction. Rotation of the pinions 56 and 51 to oppositely rotate the control unit gears 68 and 66a actuates the coupling or lost-motion means |59 and |59a to couple the gears 66 and 66a with the adjustable member 11a. On rotation of the idler gears |59 and |59a into their respective locked positions with the tooth 80a, the gears 66 and 66a are locked with the control shaft 1|, the control shaft 1| being rotated to a predetermined control position prior to such locking engagement in the manner previously explained. In practice, a push button |66 may be held closed until the shaft 1| has turned the condenser 16 to its predetermined tuning position.

With reference to Fig. 22, there is shown a modified form of the circuit of Fig. 20 which includes a remote control switch and latching means for holding the contacts |65, |61 and |68 closed after a button |66 has been operated, together with latch releasing means for opening the circuits after a tuning operation has been completed. The motor circuit includes the contacts |61 and |68 connected in parallel, with each pair of contacts being in series connection with the motor 32 and battery |95. The latching or interlocking means, designated generally as 55, is operatively associated with a centrifugal switch 45, previously mentioned, which is shown with the centrifugally actuated portion thereof attached to the shaft 36 of the tuning motor 32. It is to be understood, of course, that any other shaft which rotates during the tuning operation and stops when tuning is completed may be operatively connected with the centrifugal switch. The switch portion |10 comprises a cylindrical housing |1| with a hub portion |12 for attachment with the motor shaft 36 by a set screw or other fastening means. Positioned within the housing |1| and extending radially inwardly thereof is an annular member |13 having openings |14 therein adapted to receive corresponding flyball members |16, two of which are shown. Each of the yball members |16 has a reduced bell crank `portion |11 which passes through a corresponding slot or opening in the annular portion |13. The yball members |16 are thus pivotally supported in the annular portion |13. On rotation of the housing |1| the flyball members |16 are rotated therewith, centrifugal force moving the pawl member ends |18 radially outwardly toward the housing |1| to in turn move the inner bell crank portions |11 in an axial direction, into operative engagement with the end |82 of a slidable pin 19 slidably supported by bearing means |8| in coaxial alignment with the motor shaft 36. The opposite end |83 of the pin |19 operates the switch contact arm |86.

The switch unit 45 may comprise any convenient arrangement of contacts for carrying out any desired series of functions associated with the operation of the tuner. As shown in Figs. 21 and 22, it is comprised of three leaves or contact arms |84, |86, and |81. The contact |86 which is engageable with the pin |19 has sufficient spring tension therein so that when the motor shaft 36 is not rotating it is held in a normally closed position with contact |84. Contacts |34 and |86 are thus normally closed and contacts |88 and |81 normally open.

In the operation of the tuning circuit of Fig. 22, pushing in of a push button 66a successively closes the contacts |61, |68, and corresponding to the selected push button, which is retained in an operated position by a latch bar |88 and a co-operating stop portion |89 on the push button in a well known manner. The flyball members |16 in the centrifugally actuated portion |18 of the centrifugal switch operate on the slidable pin |19 to move the contact |86 to an open position relative to the contact |84 and into a closed position with the contact |81, the closing of the contacts |86 and |81 providing for a muting of the speaker output. It is to be understood, however, that these contacts may be connected into other circuits of a radio receiver so as to perform some other function during a tuning operation.

When the tuner has completed its cycle of operations the motor 32 stalls, by virtue of the locking action of the control mechanism for the tuning means, to in turn reduce the centrifugal force acting on the ball members |16 and permitting the spring contact |86 to operate against the slidable pin |19 and into a closing position with the contact |84. On closing of the contacts |84 and |86, a circuit is closed from the ground connection |88 through contacts |86 and |84, conductor |89, solenoid |9I, conductors |92 and |93, closed contacts |68 and |61, and conductor |94 to the battery |95. The energization of the solenoids |8| operates a core member |96 operatively connected with the latch bar |88 to pull the same out of an engaging position with the stop portion |89 of a push button |66a, whereby to release the operated button and open the contacts |65, |68, and |61. Since the solenoid |8| receives its energy from the same contacts |61 and |68 which energize the motor, the release of the push button |66a deenergizes the trip and motor circuits even though the contacts |84 and |86 remain closed after all tuning operations are completed. In other words, two sets of contacts |84- |86 and |61|68 must be closed to energize the solenoid |9|, which condition exists only momentarily during the latch tripping operation and when the motor 32 rst stalls at the end of a tuning operation. Thus the push button is automatically retained in an operated position substantially immediately on initial actuation thereof, and is automatically released on completion of tuning operations concurrently with a stopping of the operating motor.

From a consideration of the above description and drawings, it is seen thatthe invention proancona? vides controlmechanism adapted to aocomplisl'xv a setting of reversible controllable apparatus in either direction oi rotation to a predetermined control position. The invention provides also for a controlled rotation of controllable apparatus through a defined angular distance prior to its being stopped in a predetermined control position. The control mechanism is comprised oia predetermined number of rotatable elements which may be relatively constructed to provide for any desired extent of lost motion in the mechanism prior to a locking thereof to denne a predetermined control position by merely changing the gear ratio between certain of such rotatable elements. A high degree of iiexibility in accurately bringing the structure to be controlled to a predetermined control position is thus simply accomplished without in any manner changing the size of the control` mechanism or the elements with which it is operatively associated. All of the parts are of a construction such that they may be machined by stamping them out from. sheet metal or by performing a minimum number of simple machining operations on commercially available stock material. A precision mechanism is thus capable ofk being produced economically and on a high production basis.

Although the invention has been described particularly as applied to a radio tuning unit, it is not to be so limited, since it is apparent thatl it is readily adaptable to other types of controllable apparatus designed to operate at a plurality of control positions which may be anywhere within a useful operating range for the controllable apparatus.

It is to be understood that the invention has been described with referencer to specific embodiments thereof and that changes can be made therein which are within the full intended scope of this invention as defined by the appended claims.

What is claimed is:

l.. Mechanism for accomplishing a positive locking in a rotary moving structure including in combination a pair of members with one ci said members being rotatable relative to 'the other, rotary means rotatably supported on said one member for movement relative to said one member in response to relative movement betweensaid pair of members, stop means on said other member, with said rotary means having a portion for maintaining said rotary meansy and other member in a predetermined operating relationship, and a stop portion on said rotary means operatively engageable with said stop meansl to lock said two members and rotary means in xed relative positions.

2. Mechanism for accomplishing a positive locking in a rotatable-structure including in combination a pair of coaXially mounted members, with one of said members` being rotatable relative to the other, rotary means rotatably mounted upon said one member radially of said other member for rotation in response to relative rotation of said pair oi members, stop meansy operatively connected to each or said other4 member and rotary means for locking said pair of membersagainst further relative rotation after a predetermined angular movement thereof, and means for maintaining said rotary means and other member in a predetermined operating relationship.

3. Mechanism for rotating a control shaft in either direction of rotation to a predetermined control' position including in combination a pair of freely rotatable driving members, means rotating said driving members in opposite directions, an engaging member on said control shaft and common to said driving members, rotary means rotatably carried on each driving member for operative engagement with said engaging member, with said engaging member acting on said rotary means to rotate the same on rotation'y of said driving members, and a stop portion on each of said rotary means and engaging member for locking said driving members and engaging. member in fixed relative positions to define said predetermined control position.

4. Control mechanism for defining a prede-- termined control positiony in controllable apparatus including in combination a rotary member operatively connected with said controllable apparatus, a pair of elements axially spaced on said rotary member and rotatably supported thereon for relative rotation, meansior rotating saidy pair of elements in opposite directions, a third element supported in adjustably fixed posi-- tion on said rotary member intermediate said4 pair of elements, rotary means rotatably mounted on each of said pair of elements radially spaced from said third. element for operative engagement therewith, saidy third element on rotation of said pair of elements acting on said two rotary means to rotate each rotary means relative to a corresponding one of said pair of elements, means retaining each of said rotarymeans in a predetermined operating relationship with said third element, and a lockingr portion for each oi said rotary means and third element and movable therewith for looking said third element and pair of elements in fixed positions to define said predetermined control position.

5. Mechanism for accomplishing a positive stop for a rotary means at a predetermined position, including in combination a plurality of rotary members, an engaging member on said rotary means, meansl for operatively connecting said engaging member and said plurality of rotary members including lost-motion means having a rotatably mounted member, and axis means rotatably supporting said rotatable member on4 one of said rotary membersv atN ar point spaced radially from the rotary means, with said ro-v members against relative rotation to denne said" predetermined control position including gear means mechanically coupled to said shaft', said gear means having a stop portion thereon, rotary means rotatably mountedy on each of said rotary members having a gear portion in meshing engagement with said gear means, said' gear means on relative rotation of said rotary memfbers acting on said gear portions to rotate the same in opposite directions, and stop means operatively connected with each of said gear portions for rotation therewith, and engageable with saidv stop portion of said gear means to denne said predetermined control position.

'Ily A control unit for moving reversible controllable apparatus in either direction to a predetermined ccntrol position including in combination a rotary shaft operatively connected with said controllable apparatus, a pair of rotary members supported for free relative rotation, a toothed pinion mechanically coupled to said shaft intermediate said pair of rotary members and having one tooth projecting axially in both directions beyond the ends of the remaining teeth thereof, rotary means mounted on each of said rotary members, each of said rotary means having a gear portion radially spaced from said pinion for meshing engagement with all of the teeth thereof, and a stop portion rotatable with a gear portion to engage said porjected tooth for locking said pinion in a iied position with a corresponding rotary means, with the locking of both of said stop portions with said projected tooth stopping said rotary members against further relative rotation and defining said predetermined control position.

8. Mechanism for rotating controllable apparatus in either direction of rotation to a predetermined control position including in combination a rotary shaft operatively connected with said controllable apparatus, a pair of rotary member rotatably supported in an axially spaced relation for free relative rotation, means rotating said rotary members in opposite directions, adjustable means mechanically coupled to said shaft intermediate said pair of rotary members including a gear portion corresponding to each rotary member and a stop portion common to said pair of rotary members, rotary means mounted on each of said rotary members having gear means in meshing engagement with a corresponding gear portion on said adjustable :z

means, and stop means for each of said rotary means operatively connected for rotation with a corresponding gear means and engageable with the stop portion on said adjustable means, with said predetermined control position being defined when both of said stop means are in locking engagement with said stop portion.

9. Mechanism for reversely rotating a control shaft to a predetermined control position including in combination a pair of axially spaced rotary members mounted for free relative rotation, means for driving said pair of rotary members in opposite directions, means for locking said pair of rotary members against relative rotation to define said predetermined control posii tion including an engaging member mechanically coupled to said shaft intermediate said rotary members and having an axially extending tooth portion thereon, gear means rotatably carried on each of said rotary members for operative engagement with said tooth portion, said tooth portion on relative rotation of said rotary members acting on said gear means to rotate the same in opposite directions, and a stop portion included in each of said gear means for engaging said tooth portion to lock a corresponding rotary member with said engaging member, with the locking of both of said rotary members with said engaging member defining said control position.

10. Control mechanism for defining a predetermined control position in controllable apparatus including in combination a shaft, a pair of oppositely rotatable members on said shaft, engaging means on said shaft, and rotary means rotatably mounted on each of said pair of members and each rotary means including a stop portion rotatable therewith, with each rotatable member and corresponding rotary means being relatively rotatable and rotatable relative to said 20 engaging means until a locked position oi the corresponding stop portion is attained, and said control mechanism being operable until both stop portions are in locked positions at a predetermined control position for said mechanism.

ll. In a control system for a radio apparatus including a plurality of control units for selectively moving tuning means to predetermined tuning positions, said tuning means being movable between two extreme limits, electrical means for operating said control units, a circuit for said electrical means including switch means correspending to each of said control units, means corresponding to each control unit for actuating a corresponding switch means, circuit means for said radio apparatus including switch control means electrically connected with said electrical means, and means movable with said tuning means for moving said switch control means, when said tuning means approaches one of said eXtreme limits of movement, to render said electrical means and circuit means inoperative, one of said control units being adapted to provide for the movement of said tuning means to said one extreme limit, with the later operation of any one of the actuating means corresponding to the remaining control units operating said electrical means to move said tuning means and said switch control moving means therewith to release said switch control means and permit operation of said circuit means at the tuning position corresponding to the later actuated control unit.

12. A preselecting mechanism comprising a shaft having a rotational range of over 360, a coupling member normally rigid on said shaft, a pair of rotary intermittent movements, each movement having a power input and output with a step-down ratio at the output, means on each movement for defining a range of free angular travel, means for supplying power to said movement inputs tending to operate them at equal speeds, means connecting said movements and coupling member for transmitting force directly to said coupling member for shaft rotation when each movement has reached the end of its free travel range, said two movements tending to turn said shaft in opposite directions, and locking means for maintaining the relative positions of the parts of each movement to each other and to the coupling member, each movement having a free travel range corresponding to the shaft range, said locking means preventing range displacement and said movements tending to take up the free travel range and thereafter tending to turn said shaft until equal and opposite shaft turning forces define a preselected point.

13. A preselecting mechanism comprising a shaft having a rotational range of over 360, a. pair of drive members spaced axially of said shaft and each rotatable around said shaft, means for rotating said drive members at equal speeds in opposite directions, gears to be individually actuated by said drive members and each mounted eccentrically to said shaft, means disposed between said drive members and including a part normally rigid on said shaft for rotating said gears in opposite directions in response to rotation of said drive members in opposite directions about said shaft, and means controlled by movement of each gear for establishing a locking connection between the associated drive member and said shaft when the gear is rotated to a predetermined position, whereby said drive members will be actuated until both of said gears 21n havereachedv their locking positions to'determine a stationary preselection point for said shaft.

141A preselectin'g mechanism comprising a shafthavingy a rotational range of over 360, coupling means normally rigidVv onA said shaft, a drivey member rotatable' around said shaft on each side of said coupling means, means for rotating said drive members at equal speeds in opposite directions, a gear trainy between each driving member and' said coupling means, each of said gear trains including a firstr gear mounted eccentri'cally to said shaft and a second gear meshing with said first gear` and` means on one of said gears for establishing a locking connection between the associated d'rive member and said coupling means when` predetermined teeth of theftwogears are engaged, whereby saiddrive members' will actuate said gear trains until'both have reached lockingpositions to determine a stationarypreselecting pointv for said shaft.

15. A preselecting mechanism comprising a shaft having a rotational range of over 360, a pair of rotary intermittent movements each including means defining a range of free angular travel, each of said movements having a power input and a power output, means for supplying power to said movements tending to operate them at equal speeds, coupling means for transmitting force directly to said shaft for shaft rotation when each movement has reached the end of its free travel range, said two movements tending to turn said shaft in opposite directions, and means for maintaining the relative positions of the parts of each movement to each other and to the coupling means, said last-named means preventing range displacement and said movements tending to take up the free travel range and thereafter tending to turn said shaft until equal and opposite shaft turning forces are exerted on said shaft to dene a preselected shaft setting.

16. A preselecting mechanism comprising7 a shaft rotatable over a range in excess of 360, a pair of gears mounted to rotate on axes offset to but parallel with the shaft, each gear having an associated locking means rotatable therewith which can co-operate with a meshing member to determine a range of gear rotation, toothed means carried by said shaft for turning said gears throughout their respective travel ranges and for co-operating with said locking means to lock the gears at the ends of their travel ranges, and means for producing opposite relative movements of equal speeds between said gears and said toothed means until the preselection point is reached whereupon the equal and opposite shaft turning forces prevent further shaft movement.

l'l. Mechanism for reversely rotating a control shaft to a predetermined control position and for then arresting the rotation of said shaft, said mechanism including, in combination, a pair of axially spaced rotary members freely rotatable on said shaft, means for driving said members in opposite directions, and means for locking said pair of members against relative rotation to define said predetermined shaft control position including a pair of toothed members disposed between said members, axis means supporting said members for rotation about axes which are parallel to but radially displaced from the axis of rotation of said shaft, toothed means carried by said shaft and operative to rotate each of said toothed members a fraction of a revolution about its axis of rotation in response to' each revolutionv of the associatedv rotary member about said shaft, and stop means associated with each of said toothed members` for rotation therewith, and engageable with tooth parts of said toothed means to denne said predetermined shaft control position.

i8. In control apparatus for rotating a rotary control shaft in either direction, a control unit operative to rotate said said shaft in either direction to a predetermined setting and comprising, in combination, means including a lostmoti'on mechanism for rotating said shaft in one direction to said predetermined setting and for arresting the rotation of said shaft when it is rotated to saidy predetermined setting from the opposite direction, a rotatable element, means supporting said element for rotation about an axis parallel to but spaced radially from said shaft, means for rotating said element about said axis during operation of said rst-named means, and stop means controlled by said element to provide a connection for rotating said shaft in said opposite direction to said predetermined setting and for arresting the rotation of said shaft when it is rotated to said predetermined setting from said one direction.

19. Rotary control mechanism for defining a locked position for controllable apparatus comprising, a pair of coaxially aligned relatively rotatable rotary members, a rst lock portion on one of said members, a second lock portion on the other of said members, and means for effecting rotation of said second lock portion relative to said other member in response to relative rotation of said pair of members and for effecting operative engagement between said first and second lock portions in predetermined relative positions thereof to define said locked position of said apparatus.

20. Rotary control mechanism adapted to be rotated through an angular distance to a locked position with controllabie apparatus, including in combination an engaging member connected with said controllable apparatus and two elements supported for rotary motion relative to each other and to said engaging member at all positions other than said locked position, axis means on one of said elements for supporting the other of said elements in a position for rotation by said engaging member, and stop means corresponding to said other element and to said engaging member and movable upon movement of said other element into a position for locking said two elements and member against further relative movement.

21. A preselecting mechanism comprising a shaft having a rotational range of over 360, a coupling member normally rigid on said shaft, a driven toothed member on each side yof said coupling member rotatable :about an axis parallel and eccentric to `said shaft, a driving toothed member for each olf said driven members to rform two :pairs of co-opereating toothed members, each driving toothed member `forming an intermittent movement with the co-operating driven member, means for locking each. of said `driven members against idle rotation, means defining an angular range of rotation of said driven members, said ranges being `substantially equal to the shaft range and operatively coincident, and means for turning said driving members at equal speeds `and in a direction to result hnally in opposing shaft-turning forces, said intermittent movements taking up their respective travel ranges free travel ranges are taken up and for then compromising with said stop means to exert shaftturning forces on said shaft, locking means restraining said toothed members Iagainst rotation except when being rotated by said toothed means, thereby to prevent inadvertent relative movement between said toothed members and said toothed means and thus :prevent displacement of the free travel ranges of said toothed members, and means for so moving said toothed members and toothed means relative to each other that the free travel ranges thereof are taken up and then equal and `opposite shaft-turning forces are exerted on said shaft to dene a preselected shaft setting.

HAROLD F. ELLIOTT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,908,763 Kelty May 16, 1933 1,923,568 Bone Aug. 22, 1933 2,161,183 Mastney June 6, 1939 2,179,748 Mastney Nov. 14, 1939 2,344,329 McAvoy Mar. 21, 1944

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