US2266712A - Control apparatus - Google Patents

Description

Dec. 16, 1941.

5 A. CROSBY CONTROL APPARATUS Filed Aug 19, 1940 3 Sheets-Sheet 1 meld,

Dec. 16, 1941.

s. A. CROSBY CONTROL APPARATUS Filed Aug. 19, 1940 s Sheets- Sheet 2 mammalian!!! Dec. 16, 1941. s. A. CROSBY CONTROL APPARATUS Fil ed Aug. 19, 1940 3 Sheets-Sheet 5 E S BBBBSE2 m" r sionally deflected.

' Patented Dec. 16, 1941 UNITED STATES PATENT OFFICE 2,266,712 CONTROL APPARATUS Stephen A. Crosby, ChicagoQIlL, assignor to Belmont Radio Corporation, Chicago, 11]., a corporation of Illinois Application August 19, 1940, Serial No. 353,172

12 Claims.

an improved automatic tuning system for a radio receiver in which linear movement of a selector unit is transmitted through simple effective mechanism to a linear moving element of an in-' ductance unit.

Another object of this invention is to provide an improved tuning system in which a rotary control shaft and anelongated linearly movable control bar common to a plurality of linearly adjustable elements are constructed and operatively connected to provide for a simultaneous linear movement of the tuning elements and their .return to similar relative positions for a-prede J term-ined control position of the rotary control shaft.

A feature of this invention is the provision in an improved automatic tuning system of an elongated rotary control shaftwhich is of rigid construction and adapted/to be rotated by linearly actuated selector units without being bent or tor- Yet another feature of this invention is the provision of an improved tuning system for a radio receiver in which a rotary control shaft of rigid construction is substantially co-extensive in length with a laterally movable control bar common to a plurality of linearly adjustable tuning elements. -Corresponding ends of the control shaft and control bar are supported in longitudinally spaced frame members, the shaft and bar being operatively connected at such corresponding ends so that the control bar is evenly moved in a lateral direction over its entire length on rotation of the control shaft to a control position. A still further feature of this invention is the provision of an improved automatic tuning sys tem for radio receiving apparatus in which a rotary control shaft of rigid construction is in driving engagement with a frequency changing unit and in driven engagementwith a plurality of extensible linearly actuated selector units. An ail-- justable element on each selector unit is fric-.

tionally locked in, and unlocked from, an ad-, justed position on actuation of the unit to its extended and closed positions. Due to its construction and arrangement the controlshaft remains stationary during the setting of the adjustable element, so that locking and unlocking of the ele- ,tuning mechanism which may be assembled quickly and emciently with the rotary parts all substantially self-aligning so as to provide accurate structure which may be assembled in a practical manner. 7

Further objects, features, and advantages of this invention will-become apparent from the following description when taken the accompanying drawings in which:

Fig. 1 is a plan view of the invention;

Fig 2 is a sectional view taken along the line 2-2 in Fig. 1; 3

Fig. 3 is a fragmentarysectional view as seen along the line 3 in Fig. 2;

Fig. 4 is a--fragmentary bottom view'showin'g the motion transmitting mechanism between the control shaft and the control bar;

Fig. 5 is a front elevation of the rotary treadle bar or control'shaft; w

Fig. 6 is an enlarged detail view of one of the two self-aligning bearings for the treadle bar;

Fig. 7 isa developed view of the treadle bar or body member for the control shaft, and

Fig. 8 is a cross-sectional view illustrated similarly to Fig'. ,2 but showing the parts thereof in changed position.

Referring to the drawings there is shown in Figs. 1 and 2 a tuning device having frame or housing means including end walls ll, a'front panel l2 and a removable top cover II. The" housing is divided into an and a lower compartment upper compartment l4 It by a bracing mem- I1 adapted for supporting the tuning unit in the radio chassis (not shown). Tuning from one frequency to another in the illustrated structure is accomplished by permeability or inductance tuning. It is contemplated that the inductance coil units. C (Fig. l) be of the coil and core type and suitably positioned in the compartment IS, with the usual metal cores M being slidably movable in the coils N, and in operative connection as at .20, with a control bar l8, extending longitudinally of the tuning device. The control bar I8 is of substantially U-shape and is mounted near its opposite ends on connecting members H which are slidably supported for linear movement in connection with transversely of the compartment I8 in laterally extending ears or projections 2I integrally formed on the side walls II at elongated apertures 22. The movement of the bar I8 transversely or from front to back of the compartment I6 is limited by its engagement with the ears 2I acting as stops.

Bar I8 is provided with an extending end portion 23 for the operation of additional inductance units (not shown) which may be assembled out- 10 side of the housing such as when the radio re-- ceiving apparatus is to be used for operation over a plurality of frequency bands. With the inductance units arranged in a spaced relation longitudinally of the bar I8 it is apparent that the bar I8 is of relatively long length between its supporting members l9. Also in the operation of frequency changing means utilizing movable cores or slugs M, the tuning efllciency is dependent upon a simultaneous linear movement of the slugs and their return to similar relative positions for a predetermined position of their common control, such as the bar I8. A uniform linear movement of the control bar I8 over its entire length is accomplished in the present invention by a treadle bar or rotary control shaft 24, to be explained, which is of a length substantially equal to that portion of the bar I8 within the housing and supported in the end walls II so as to provide for the operative connection of motion for actuation of the control bar I8. The

rotary control shaft or treadle bar 24 is provided with a fixed arm or and piece 28 and 28' at each end thereof (Fig. 5) and the free end of each arm is pivotally connected at 29 to one end 3I of a link or driving arm 32. of the lever 32 is connected at 33 to a segmental gear 34 which is rotatably supported on a stu shaft or pin 36 mounted in an end wall II. Angular displacement of the segment 34 is limited by stop members or ears 3'! which are punch- 60 formed in the wall II. Gear 34, as is clearly indicated in Fig. l, is formed with a peripheral groove of substantially semi-spherical shape having teeth thereon for engaging corresponding teeth formed on a non-rotatable but linearly movable rack member 38. The rack 38 is of circular section and is connected at 39 to the connecting member I9. The rack is supported for linear movement transversely of the tuning unit by the connection 39 and by its arrangement between the gear 34 and an idling pulley 4I (Figs. '2 and 3). A rubber collar 481s carried in the groove in the pulley H to frictionally engage the rack 38, but at the same time provide a smooth, uniform feeding action between the rack and pulley.

The pulley 4| is rotatably mounted at one end 42 of a coiled springs 43 (Fig. 4) The body portion of the spring is supported on a pin 44 mounted in the end wall II, while the opposite end 48 of the spring is of hook shape and locked in a recess or notch formed in the bottom side of the end wall II. Spring 43 is placed under tension in a usual manner to yieldably urge the pulley 4| against the rack 38 at all times to hold The opposite end 45 it in engagement with the gear 34. In the operation of the link assembly 26 it is apparent that rotation of the treadle bar 24 pivotally moves the lever 32 to drive the segment 34, which in turn linearly moves the rack 38 laterally of the tuning device, whereby to actuate the control bar I8 to operate the inductance tuning units, (not shown). It is understood, of course, that the direction of linear travel of the rack 38 is dependent upon the direction in which the treadle bar 24 is being rotated, as will be explained. Backlash between the gear 34 and rack 38 is substantially eliminated by the continuously applied spring force exerted on the idling pulley 4! by the spring 43.

Backlash in each of the motion transmitting assemblies 26 is further reduced by the spring retention of the pivotal connection points or axis means 29 and 33 in a substantially fixed position relative to the arm 32'. A tie plate 41 (Figs. 2 and 3) is pivotally connected near one end to each of the axis means 29 and 33, with the opposite ends of the plates 41 being connected together by a spring 48 arranged in tension therebetween. A spring force is thus continuously applied on the axis means 29 and 33 in a direction to pull them together so that the distance between their respective centers is substantially the same for all operating positions of the lever 32. Any lost motion of the axis means 28 and 33 in their corresponding apertured supports in the lever 32 is thus practically eliminated. The conneeting structure between the control bar I8 and treadle bar 24 is thus positive in action whereby a substantially immediate and precise linear movement is imparted to the control bar I8 on rotation-of the control shaft 24, which will 7 now be explained.

The treadle bar 24 (Figs. 5 and 7) includes a body member 49 and end pieces or arms 28 and 28. In one embodiment the body member is formed from a single piece of flat sheet steel,

which is copper-plated, for rust-proofing, and

to facilitate and improve welding of the bar as will be explained. The entire unit illustrated in Fig. 5 is described as the treadle bar and this includes the body portion which is of substantially rectangular shape as is shown in Figs. 2 and 8. This piece of metal is first formed, as by a punch press operation, with longitudinally extending relatively spaced apertures 5I and longitudinally extending ears or flaps 52 before being press formed into the V-shaped hollow section. The apertures 5I are located in a side portion of the bar 24,"and arranged between longitudinally extending projections or engaging portions 53 and 53' which are formed during theshaping operation. Also in the forming operation the ear portions 52 are bent laterally of the bar, the body member 49 and the arms 28 and 28' being soldered or welded together at the portions 52. The seam S at the apex of the triangular crosssection is welded to provide rigidity against torsional deflection or twist. Axis means 54 and 54' are mounted in the end pieces or arms 28 and 28' respectively for rotatably supporting the bar in the end plates II. The location of the axis means 54 and 54 thus determines the longitudinal operating axis of the treadle bar. As is clearly apparent from Figs. 2 and 8, the bar 24 is substantially symmetrical about a plane passing through line 25-25 (Fig. 8) which plane includes the longitudinal axis of the treadle bar and is normal to the bar side having the longitudinally projecting portions 53 and 53 and apertures L. This bar construction provides'for a bar of high rigidity and'stiffness against both bending and twisting. Thus, even though the bar is of relatively long length and supported only at its ends both torsional and bending deflection in the bar is entirely eliminated during its operation by the selector units 56, as will be explained.

In order to insure a free-running, accurate treadle bar, it is essential that substantially perfect alignment is provided between the bearings for the shaft members 54 and 54'. Alignment is accomplished in a rapid, accurate assembly process for the tuner by means'of spherically surfaced bearings B (Fig. 6), seated in a bevelled aperture C in each end wall A spring D is secured to the wall II by means of rivets E extending through oversize apertures F in the spring so as to permit relative movement between the wall H and hence the aperture C and the spring D. The body portion of the spring around the aperture G is under tension and presses directly inwardly at right angles to the wall With this construction the spring may shift relative to the'wall so that the aperture G aligns with the aperture C, but with the spring pressure being directly inwardly the bearing B aligns properly in the seat, and the two shaft members 54 and 54' align with respect to one another. A lock washer H in a corresponding groove in the shaft member 54' cooperates with the shoulder I and prevents any undue thrust in that direction of the treadle bar. The shaft member 54 is notlocked in the bearing in this manner as can be seen in Fig. 5. However, the shoulder J is far enough from the corresponding bearing B as shown in Fig. 1, that there will be no binding between the shaft member and hearing at that end of the treadle bar assembly.

Prior to the assembly of the bar 24 in the tuning device, a gear segment 51 is secured as by welding or soldering to the end piece 28. Segment 51 is adapted for meshing engagement with a pinion 58 mounted at one end of a manually rotatable tuning shaft 59. Rotation of the shaft 59 by the tuning knob 6| tunes the frequency changing means, whether it be inductance or condenser structure, to a given frequency through the link assembly 26, in an obvious manner. The dial supporting frame and associated structure is broken away in Fig. 8, because of its considerable height. Tuning indicating structure mounted on the top cover I3 is connected withthe shaft 59 through the pulley and string assembly 63. This structure in addition to the pulley and string assembly includes a dial 62 and pointer 62'.

During automatic operation of the tuning apparatus rotation of the treadle bar 24 is accomplished by the station selector units 56, previously mentioned, which are linearly movable and slidably supported in the front panel I2 and in a bracket member 64 (Fig. 2). Each unit 56 includes an actuating member 66 and an operating member 61 which are assembled in an interlocked but slidable engagement. The oper ating or carriage member 61 -(Fig. 2) is of fiat irregular shape and is formed with a body portion 68 and a finger portion 69. The body portion is provided at ,one end with an adjustable element 1| pivotally supported on a pin 12, and

is formed at its opposite end with a laterally projecting T-shaped ear 13. Inwardly facing L-shaped apertures 14 are formed intermediate the elements 1| and the ear portion 13. The

actuating member 66 is also of substantially flat shape and is provided with longitudinally extending laterally bent portions 16 having a substantially T-shaped aperture 11 formed therebetween. Bent oppositely to the portions 16 and at one end of the actuating member 66 are leg portions 18., Thus in the assembly of a unit 56 the leg portions 18 are positioned in the widened portion of the apertures 14 to-provide for their dovetailed engagement with the carriage member 51 in a usual manner, the T-shaped portion 13 being dovetailed with the member 66 by its initial positioning in the widened portion of the aperture 11. This dovetailed engagement, which is clearly shown in Figs. 1 and 2, provides for a relative longitudinal movement of the members 66 and 61 so that each unit 56 may be extended and contractedwithout permitting the members 66 and 61 to become disengaged except at the initial assemblying position just described.

The cam 1|, previously mentioned, is of relatively narrow width and of semi-circular section having flat diameterportions 19 and 19' arranged on opposite sides 'of .the pivot pin 12. A -fiat spring 8| of slightly arcuate form in a longitudinal or lengthwise direction (Fig. 1) is arranged on the operating member 68 between the cam- 1| and a bumped out lip portion 82 formed on the operating member'61 in a substantially central position between the apertures 14. Spring 8| is arranged between the leg portions 13 on the actuatingmember 66, and in slidable engagement therewith. By virtue of the entire assembly, slight movement of the spring 8| rela tive to the actuator structure is permitted both longitudinally and transversely when the members 66.and 61 are in their open position. In this position the cam 1| is entirely free of any frictional pressure as exerted by the spring 8| and is freely movable about its pivot point 12. On moving of the members 66 and 61 into their closed or contracted position, the push rod or actuating member 66 slides on the springfll to urge the spring laterally with somewhat of a wedging action between the spring and the carriage member 61. This action of the push rod 66 provides for the exertion of the spring pressure both longitudinally and laterally of the spring, so that the spring acts as a toggle to apply a magnified loading pressure on the adjustable cam 1|, whereby to frictionally lock the cam in the angular position which it has at the time the members 66 and '61 are being closed. The cam 1| is released from its locked position simply by pulling the member 66 outwardly relative to the member 61 to its open position,

so that th spring 8| is permitted to bow outwardly and the tension is removed.

The normal operation of the selector unit 56 idle or rest position. As indicated in Fig. 8, the

cam 1| and treadle l e-11,24 are shown as being inclined toward each other with the engaging portions 53' and 19 closer together than the engaging portions 53 and 19. Thus on actuation r the unit 56, by pushing on tn knob 80, the

portions 53 and 19 are first brought into engagement, the continued linear movement of the unit 56 effecting a clockwise rotation of the bar 24 until ermagement is made between the portions 53 and 79, as shown in Fig. 2. This engagement of both pairs of corresponding portions 53 and I9, and 53 and I9 represents the home or tuned position of the unit, an aperture I being arranged to receive the cam pin I2 when the unit 56 is in such position. The radio receiver is thus tuned from the condenser setting indicated by the position of the treadle bar in Fig. 8 to the changed setting shown in Fig. 2, the selector unit after release being returned to its idle position by the action of the coil spring 83 which is mounted on the finger 69 and arranged in compression between the bracket 64 and the body portion of the carriage member 61. This action of the unit is similar for any relative positioning of the bar 24 and the cam H, the degree of angular movement of the bar 24 being transferred to a linear movement in the control bar I8 by the motion changing link assemblies 26.

It is readily apparent that a most eflicient and satisfactory tuning of a radio receiver is accomplished when the linearly adjustable tuning units (not shown) operated by the control bar I8 are equally and concurrently moved at all times by the bar I8. ,Since the bar I8 is of relatively long length a simultaneous and similar movement of its end portions best provides for a precise moving of all of the tuning units to similar relative predetermined tuning positions. This movment of th control bar I8 is accomplished in the present invention by having the treadle bar 24 substantially co-extensive in length with the control bar I8. Thus, since the bar I8 is in driven engagement with the shaft 24, the location of the motion changing means 26 at each end of the shaft 24 provides for the application of the driving force on the bar I8 at opposite ends thereof. This arrangement is not obtainable with the treadle-bars of the prior art, since these bars are of relatively short lengthand when extended are subject to appreciable bending and torsional deflection. The occurrence of this deflection in the treadle bars .of the prior art distorts or impairs the uniform transmission of the rotary motion of the treadle bar to the ends thereof.

However, the rigid and stiff construction of 'the treadle bar 24, as previously described, positive- I ly eliminates any torsional or bending deflection in the bar during its rotation by a selector unit 56. 'Each link assembly 26, is thus simultaneously operated through the connecting arms or end pieces 28 and 28 to move the opposite ends of the control bar I8 concurrently so that the bar and the slugs connected thereto are all maintained in proper alignment. Since the link assemblies 26 are substantially free of any lost motion, rotation of the treadle bar 24 for either direction of rotation is immediately and positively transmitted to the bar I8 to provide precise adjustment of the inductance tuning units. As is clearly indicated in Fig. 1, the selector units 56 engage the treadle bar 24 over only a central portion thereof, but its overall length corresponds with the length of the bar I8 within the control device housing. However, additional selector units may be provided on either side of the units 56 illustrated without in any way affecting the satisfactory operation of the treadle bar 24. The trough-shaped configuration of the bar, and the fact that it is connected into the transmission mechanism at somewhat spaced apart points, makes it rigid enough over its entire length so that additional slug units can be carried on the extension 23 and be maintained in proper alignment.

In the adjustment of the cam II to set it to a predetermined angular tuning position, the station selector 56 is extended to release the cam 'II from the locking pressure exerted by the spring 8I. This extension of the selector unit 56 is simply accomplished and is best described with reference to Fig. 8, where the unit is shown in its idle position with the carriage member 6! in abutting engagement with the panel wall I2. The member 66 is thus moved relative to the carriage 61 by pulling outwardly thereon to the right, spring BI being released as above described. The treadle bar 24 is turned to a particular tuning position by operation of the tuning knob 6|, this position being indicated by the tuning scale 62. On the application of manual pressure on the push rod 66 at the knob 80, the initial friction between the rod 66 and the spring 8| is sufficient to provide for a concurrent linear travel of both the push rod and carriage member 68 against the pressure of the spring 83. On engagement of a cam portion I9 or I9 with a corresponding portion 53 or 53 on the treadle bar 24, the cam I I, by virtue of its free pivotal movement when the members 66 and 61 are in an open position, is rotated angularly in a direction depending upon which pair of the corresponding engaging portions is initially engaged. This rotation of the cam is continued until both pairs of corresponding portions are brought into engagement, this position representing the home or tuned position of the selector unit 56. On a continued movement of the push rod 66 the push rod, carriage, and cam are securely locked by the spring 8I in a relatively fixed position, representing the contracted or closed position of the selector unit 3|, with the cam II being adjusted to the particular tuning position of the bar 24 as set by the operation of the tuning knob 6|. On release of the push rod 66 the selector unit 56 in its contracted position is returned-to its starting or idle position by the return spring 83. Later actuation of the unit will thus rotate the bar 24 from any position which it might have to a position corresponding with the angular adjustment of the cam 'II to tune in a desired predetermined station. I

After thetreadle bar 24 is rotated to the desired predetermined station position by the knob 6|, it remains stationary while the adjustable element or cam II is set or adjusted. When the member 66 is pushed into friction locking position relative to the carriage and the locking spring, the force applied on the knob 88 by virtue of the aligned arrangement of the pivotal axes of the adjustable cam 1| and the treadle bar 24, is directed in line with the axis of the bar 24. The rigid construction and non-deflection of the treadle bar retains this axes alignment and hence precludes any turning movement of the applied force about the axis of the treadle bar. The radio operator thus need only use one hand in all of the manipulations of the selector unit 56 described so that the adjusting operation of the cam 'II is a simple operation and substantially similar to the ordinary tuning operation.

Although the invention has been illustrated with reference to a single embodiment it is not to be so limited, but is tobe limited only by the scope of the appended claims.

I claim:

1. In control apparatus,.rotary control means adapted to be turned to predetermined control positions, said means having a body member of hollow section, said body member being provided with parallel axially extending portions formed along the edges of one side thereof, said axially extending portions being equally spaced on opposite sides of the longitudinal axis of said body member, with said one side having a plurality of axially spaced slots arranged between said axially extending portions, and an end piece secured to each end of said body member having axis means mounted therein.

2. In radio tuning apparatus having a plurality of linearly actuated selector units, the combination of an elongated rotary control member common to all of said selector units, said control member being of hollow substantially V-shaped section and symmetrical about at least one plane extending axially thereof, with the axis of the control member lying in said one plane, said member having one side thereof formed with a pair of axially extending approximately radially.

projecting portions lying in a plane substantially normal to said plane of symmetry, said selector units being engageable with said projecting portions to rotate said control member to predetermined control positions. 7

3. In control apparatus having frame means including a pair of longitudinally spaced end plates, and a plurality of tuning units longitudinally spaced between said plates, the combination of an elongated control means rotatably supported in said end plates, said control means being of rigid construction over the entire length thereof, a linearly movable elongated control bar slidably supported in said end plates and in operative engagement with said tuning units, and means for transmitting the rotary motion of said control means to linearlymove said control bar,

7 providing radial rigidity over its entire length,

said means being connected between correspond ing ends of said control bar and said control means, the unyieldable construction of said control means providing for a simultaneous move-' ment of said transmitting means to uniformly move said control bar over the entire length thereof.

4. In control apparatus having housing means including a pair of longitudinally spaced end plates, a supporting member extending between said end plates and dividing said housing means into a pair of compartments, a control member rotatably supported'in said end plates, a plurality of linearly actuated selector units slidably supported in saidhousing means to selectively move said control member, said control member and selector units being located in one of said compartments, a plurality of tuning units longitudinally arranged between said end plates, a control bar common to all of said tuning units and movably supported in said end plates, with said control bar and tuning units being located in the other of said compartments, and means for transmitting motion from said control member to said control bar, with said means being connected to the corresponding ends of said control member and control'bar. I

5. In control apparatus having frequency changing means and a plurality of selectorunits, the combination of frame means including a pair of longitudinally spaced end plates, a control member rotatably supported in said end plates and adapted to be engaged by said selector units for rotation thereby to predetermined control positions, with the length of said member engageable by the selector units being substantially less than its entire length, a linearly movable control bar slidably supported in said end plates for moving said frequency changing a all by a one-hand manipulation ,of the selector so that said inotion transmitting means will be similarly moved onrotatlon of said control member to uniformly move said control bar over the entire length thereof.

6. Radio tuning apparatus including in combination an extensible linearly actuated selector unit including a pair of relatively movable members and an adjustable element axiallysupported on one of said members, said element being locked in an adjusted position when the selector unit is in a closed position, a rotary control member of rigid construction and-radially unyieldable over the entire length thereof, axis means for said control member .with the pivotal axis of said adjustable element and the axis of said control'member being arrangedin substantially the same horizontal plane said control member having a portion engageable by the adjustable element on normal tuning, actuation of said selector unit, with the adjustable element being movable upon the relative. extension of the pair of members in the selector unit} said rotary control member having an inertia such that it remains stationary upon engagement of its engageable portion by the adjustable element, with continued movementof the selector unit after such "engagement causing, the adjustable element to adjust itself to the rotary position of thecontrol member without movement of said control member and being locked in such position by relative movement of the membersof the selector unit to-closed position, said adjustment of said element being accomplished without manual hold-,' ing of the control member and said element -be-f ing frictionally locked-in an/ adjusted position ,-trol' means, linearly actuated selector units for trol means, linearly actuated selector units fcr operating said control means and linearly adjustable frequency changing means, the combination of means for transmitting the motion of said control means to said frequency changing means including a gear segment and a driving arm, axis means pivotally connecting one end of said driving arm with said gear segment, a second axis means pivotally connecting the other end of said driving arm to said control means, spring means arranged in tension between said two axes means to retain said axes means in a substantially fixed I position relative to said driving arm, a linearly movable threaded member in operative engage- ,ment with said frequency changing means and with said gear segment, and a spring tensioned idler pulley engageable with said threaded member and arranged to yieldably urge said threaded member into engagement with said gear segment to prevent any backlash therebetween.

9. In tuning mechanism having a plurality of selector units mounted in frame means, including a pair of end portions, with a bearing aperv ture in each end portion, the combination of a relatively long rotary control unit selectively engageable by said selector units, said control unit having a shaft portion at each end thereof, and bearing means for each shaft portion at the bearing aperture in each end portion to provide for accurate alignment of the shaft portions with respect to one another, said bearing means including a bearing member having a spherical surface over a portion of the outside surface thereof-and having an axially extending bore therein, with said bearing member seated in the corresponding bearing aperture and movable relative thereto, and spring means secured to one side of the corresponding end portion but movable relative to said end portion having a yieldable body portion engaging said bearing member and exerting a force in an axial direction I thereon to maintain said bearing member seated in said bearing aperture and yet permit relative movement therein so as to obtain alignment between the bearing members insaid two bearing means.

10. In tuning mechanism having a plurality of selector units mounted in frame means including a pair of end portions with a bearing aperture in each end portion, the combination of a selfaligning bearing unit at each bearing aperture, and an elongated rigid rotary control unit having a shaft portion at each end and spaced apart by an elongated rigid body portion having a plurality of sides radially disposed from the" axial center of the control unit but connected with one another including an axially extending engaging side and at least two sides substantially oppositely disposed from said engaging side, with said unit being hollow withinsaid plurality of sides, and said two sides being secured together .in a

closed seam at one edge of each to maintain said body portion rigid against torsional deflection, and with said body portion being maintainedagainst bending by said hollow construction, witha shaft portion joumalled in each self-aligning bearing unit and said bear ng units adapting themselves to an aligned position between said two shaft portions on said rigid body pgii'tion to provide a free-running otary control u t. a

11. A rotary control unit for radio tuning mechanism having means for supporting said unit, and a plurality of selector units for engagement with the control unit, said control unit including a hollow body portion having an axially extending engaging side radially disposed i'rom the axial center for said.control unit, and a portion substantially oppositely disposed from said side having an axially extending closed seam providing stiffening for said control unit in an axial direction to prevent twisting thereof, and axis means at each end of said body portion and secured thereto for mounting said control unit in the tuning mechanism;

12. Control apparatus including in combination movable control means having a movable control member, a selector unit carrying adjustable means for operating said control member, said selector unit having manual means adapted for movement in a pullable or pushable action in a direction substantially away from or toward said adjustable means to hold or release said adjustable means, said control means having an inertia such that it remains stationary upon connection of its control member and said adjustable means while the adjustable means is in 9. released position, with continued movement of the selector unit after such connection causing the adjustable means to adjust itself to the position of the control member without movement of the control member, and said adjustable means being held in said adjusted position by one of such movements in one of such directions relative to said adjustable means after such continued movement, said adjustment of said adjustable means and holding thereof in the adjusted position being accomplished by a onehand manipulation of the'selector unit without manual holding of the control member;

STEPHEN A. CROSBY.

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