US2002443A - Remote control device for radioreceivers - Google Patents

Description

May 21, -1935. A. A. THOMAS REMOTE CONTROL DEVICE FOR RADIORECEIVERS Filed Oct. 26, 1929 7 Sheets-Sheet l INVENTOR VOLUME May 2l, 1935. A. A. THOMAS 2,002,443

REMOTE CONTROL DEVICE FOR RADIORECEVERS Filed Oct. 26, .1.929 7 Sheets-Sheet 2 May 21, 1935. A. A. THOMAS REMOTE CONTROL DEVICE FOR RADIORECEIVERS Filed Oct. 26, 1929 7 Sheets-Sheet 3 May 2l, 1935- A. A. THOMAS v 2,002,443

REMOTE CONTROL DEVICE FOR RADIORECEIVERS Filed Oct. 26, .1.929 '7 Sheets-Sheet 4 XWMM vMay 21, 1935. A. A. THOMAS REMOTE CONTROL DEVICE FOR RADIORECEIVERS 7 sheets-sheet 5 v Filed Oct. 26, 1929 VOLUME May 2l, 1935. A. A. THOMAS REMOTE CONTROL DEVICE FOR RADIORECEIVERS 7 Sheets-Sheet 6 Filed QCt. 26, 1929 May 2l, 1935. A. A. THOMAS REMOTE CONTROL DEVICE FOR RADIORECEIVERS Filed OC. 26, 1929 '7 Sheets-Sheet 7 fy/MW Patented May 21, 1935 PATENT OFFICE REMOTE CONTROL DEVICE FOR RADIO- RECEIVERS Adolph A. Thomas, New York, N. Y.

Application October 26,

36 Claims.

y My invention relates to radio receivers, and its object is to provide a simplel device for tuning a receiver from a distance. For this purpose I utilize a small control box having a suitable knob or button which operates a pivoted switch arm arranged to engage a series of contacts. These contacts represent certain stations, and an indicator movable with the switch arm enables the operator to select the station wanted. The control box is electrically connected to the receiver for controlling an electric motor which drives the tuning shaft at properly reduced speed in alternately opposite directions. In a preferred form of my invention, the tuning shaft carries a contact arm movable over a series of radially arranged contacts which are connected to the selector contacts in the control box. To bring in a desired station, a person turns the knob or other finger piece on the control boX until the indicator pointsl tothat station. The finger piece (or a separate button) is then pushed down, whereby the necessary circuits are automatically closed to operate the tuning shaft until the wanted station is in tune. When that occurs, the contact arm on the tuning shaft closes a circuit to energize a switch-operating coil which opens the motor circuit, so that the shaft remains in tuning position.

The control box may have a signal lamp which lights up when the tuning shaft stops, whereupon the operator lets go of the switch-closing iinger piece. I may provide switch connections in the box for keeping the loudspeaker silent during the tuning operation. When the control knob or button is released, the loudspeaker is automatically rendered operative. In one embodiment of my invention, the control box has a single knob for rotating the selector arm and closing the motor circuit. The latter function is accomplished by mounting the knob like a push button capable of axial movement in addition to its rotary movement. In that case the switch arm is normally spaced from the contacts and is turned without engaging them. When the knob is pushed down after a station has been selected, the switch arm is moved into engagement with the contact representing the station, and at the same time the motor switch is closed. I may, however, close the motor switch by a separate push button preferably mounted in the center of the rotary knob. That construction eliminates the necessity of mounting the rotary knob for axial movement, and the selector arm may therefore engage the contacts during its rotary movement.l In a less simple form of my invention,

1929, Serial No. 402,571

(Cl. Z50-20) the rotary switch arm and associated contacts in the radio receiver for stopping the shaft in selected tuning position may be replaced by a series of rotary disks provided with contact switches arranged radially to represent certain stations.

The novel features and practical advantages of my invention will be understood from a description of the accompanying drawings, in which- Fig. 1 shows a top view of a preferred form of my new control box;

Fig. 2 is a section on line 2--2 of Fig. 1;

Fig. 3 represents an inside plan view on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary detail View of a switch in the control box;

Fig. 5 is a section on line 5 5 of Fig. 4;

Fig. 6 is an enlarged section through the insulating base of the control box to show the mounting of certain switch contacts;

Fig. 6a is a section on line lia-6a of Fig. 2;

Fig. 7 shows a sectional detail of the lamp support in the control box;

Fig. 8 is a side view through a radio receiver embodying certain features of my invention, some parts being sectioned for clearness;

Fig. 9 shows a front View on line 9-9 of Fig. 8;

Fig. 10 is a plan view of Fig. 8;

Fig. 10a is a section on line IDa-la of Fig. 10;

Fig. 11 is a detached View of certain switch mechanism in the receiver;

Fig. l2 shows a form of indicator plate used in the receiver of Fig. 10;

Fig. 13 is a diagram of circuit connections between the control box and the radio receiver;

Fig. 14 shows a top view of a modied form of control box having a movable indicator disk inside;

Fig. 15 is a section on line |5-I5 of Fig. 14;

Fig. 16 represents a sectional plan View on line IG-IS of Fig. l5;

Fig. 17 shows the indicator disk in the control box of Figs. 14-16;

Fig. 18 is a diagram of circuit connections between the control box of Figs. 14-16 and a radio receiver having a series of contact disks;

Figs. 19 and 20 are respectively side and plan views of a suitable arrangement of the contact disks and associated switch arms used in Fig. 18;

Fig. 21 is a sectional view of a third form of control box with a rotary selector knob and a separate push button for the motor circuit;

Fig. 22 represents a plan section on line 22-22 of Fig. 21;

Figs. 23 to 25 show still another construction of control box in which a finger piece swings in an arc to select the desired station, Fig. 23 being an outer plan view, Fig. 24 a side section on line 2li- 24 of Fig. 25, and Fig. 25 a plan section on line 25-25 of Fig. 24; and

Fig. 26 shows a detail in section on line 26-26 of Fig. 24.

I shall describe first the apparatus shown in Figs. l-13. The mechanism for controlling the position of the tuning shaft in the radio receiver is housed in a small casing IB, which is here shown as a flat cylindrical box consisting of an insulated base I2 and a cup-shaped body I3 removably see cured to the base by screws I4 or otherwise. The base I2 can be molded of bakelite or other suitable insulating composition, and the casing part I3 is easily made of spun sheet metal or shaped of ber, hard rubber, pulp, celluloid, and the like. If desired, the top plate or cover I5 of box 0 may be made as a separately removable part. A rotary hand knob I6 projects through an opening I1 in the top of box I0 and carries a pointer i3 arranged to move over a scale I9, which in this instance represents ten selected broadcasting stations. identiiied for convenience by the letters A-K; A push button 2D extending through an axial opening in knob IbV is adapted to close the necessary circuits for operating the tuning shaft after` the pointer I.8 has been moved to the desired station on indicator I9. A knob 2 IY is adaptaolfj ed to control the volume of reproduction, and a switch member 22 throws the radio receiver into and out of operation. The outline 23 in Fig.. 2 represents any practical form of on-and-off switch operated by the linger pieceY 22. Likewise, the outline 24 in the same gure is intended to indicate any. practical device for regulating-the vol ume of the loudspeaker by turning the knob 2|. This will be understood without further description.

Theinsulated base I2 of lcontrol box III. is provided withasemi-circular ange or bridge 25, which may be molded integral with thev base. The bridge 2.5 has.y a seriesof slots126 in which contact pieces 2:1: are inserted in a tight t, so that they remain fixed without additional fastening means,

"-`the box. The bridge 25 has a lateral' extension g; I3;l of casinaA |13, so-y that alli electrical. connections althouglrrgsuch may be used if desired. The. contacts 21 may be outfrom strips or sheets of brass or other good conducting metal'. As seen in Figs. 2i and` 6, the top edges of contacts 21 are slightly below the top surfaceY 2.3. of bridge 25,. andv the openfends of slotsl 26.= arev widened at 29' for av purpose that will presently be explained. While thisv particukir 'mountingV of the contacts 21 is not absolutely necessary, it has practical advantages. 'lopermit the easy attachment of conductors to the insulated-:contacts 21s,. these may be provided with extensions 3D having perforations: 3.Ii or-'otherlmeans for connecting a wire. The radial arrangement of contacts 21.` correspond' to the position of the radial indicator lines I9'l on top ofbox IBS. In the device as prepared for the market, the contacts 21 may be arranged equidistantly, so that the scale markings I9v are-uniformly spaced to improve the appearance of or shelf l32 to the underside of which is secured a Contact strip 33 of kbrass or other suitable metal. Screws 34. or the like may be used for attaching xthe contact strip 3,3 to shelf 32. Asemi-circular `"projection 3 5 on base I2 supportsa contactstrip 36,- which. may be` attached by screws or. other- Wise. All the Wiring that goes into box I0riscon'- tained-ina cable-36 which passes through a-.slot

. which may also be used may be made before the casing is inserted over base I2.

The rotary knob I6 has a tubular extension or sleeve 31 in which the push button 20 is slidably mounted. The members I6 and 31 may be molded as a. single piece of insulating material. A lock nut 38 screwed on sleeve 31 prevents axial movement of the sleeve Without interfering with the free rotation of knob i6. The push button 20 carries a cross-pin 39 arranged to engage at its projecting ends in a pair of axial slots 4B in sleeve 31, whereby the push button is locked to knob I6 for rotary movement therewith. At the same time, the push button 2li is free to be depressed in any position of pointer i8. The push button 20 is connected at its lower end to the top of an insulating block 42. For convenience of manufacture, the parts 22 and 42 may be cast or molded as one piece, preferably of insulating material. A switch arm 43 is providedV with an annular base L34, which ts over the pushbutton 20 and is secured to the top of part ft2Y by screws i5 or otherwise. One of these screws may' be used as a binding post for connecting a con-V ductor to; switch arm 4.3,. which is preferably made o1 spring brass or simil-ar material. The insulatn ing block 42 has. a recess 25 for receiving a coil spring 4.1. The base I2 may be provided with a recess dit in which'. the lower end of spring 41 is seated against lateral displacement. The spring' #t1 tends to expand and normally holds the pus-liv button 20 and all,l connected parts in raised posi'-` tion. The sleeve 31 forms a guide and?. bearing" ior'the push; button.. The lower end of insulating block. 2 provided with ai pair of lateral projections or anges Q9* and 523, which carry two1 switch arms 5I. and 52 respectively. These arms are attached. to the. flanges by screws or bolts 53, as. binding posts for con-- ductors.` The three switclr arms-43, 5i and 52 are preferably' formed at their' free` endswith a nose' or lateral ofiset 54 forl the purpose of making goed; electrical. contact in: operative position.

Referring; tn Fig.. 2,. it is seen that, when the movable parts' aref in normal raised position une der* the action. of coil' spring d'1, the' armvv i3 is above thez bridge member 215T and? the arm 5I- is above the contact strip 36. At the same time, the: swiltch. arm.L 52 is; held?. in: pressurel enga-gement witlr the'. underside of contact strip 33: When. thebutton. 20:' is pushed down, the' switch arm. 4'3; is. moved; into pressure enga-gement with one ofthe insulateducontacts 211', andy the switch arm; 5I. engages. the xedi contact strip-1 33?. In the. down position; of button Ztl-the third switch arm; 521is out of. engagem'entwitli Contact strip AsA previously explained;v the button 2U is not pushedY down. untill after the pointer I8 lfiasllfieenI rotated: toithe desired indicating position. Since'v thecontacts2 1.' are inlalign'rnent lines. I'9 onthe topot box lf2-git follows that tlieV switcharin. 435 will: always engage theI partcula-r"I contact 2:1? that representsL the station indicatedby pninter I8; Reierringto-Fig. 2, it willibeseen that the bevelledfrecesslatthe-top-of each contiact 2.1 will? guide they nose4 properf engagement with the contact-. Thismeans that', even' ifi theA pointer I3 should be slightlyout of alignment with theindicator mark d'9:ofthe.selectedlstationptheswitch arm 43 Will. be.- guided into proper contact position by; the bevelle'drecess29. Whenithe'knob I 5' is rotated; the'finsulatingblock- 421 and-'the' three switch* arms' 113-; 515 andi 5Z` carried thereby.v are rotated4 asf-a1 sinif glef member; The stationary Contact strips 33V`A withitlie indicator 511 of switch arm 43 into and 36 are of such extent as to cover the full range of movement of knob I6.

The insulating base |2 of control box |0 has a bracket which carries a socket 56 for receiving the base of a small signal lamp 51. The bracket 55 may be an integral projection of base |2 if the latter is cast or molded. A spring contact 58 secured to bracket 55 engages the central contact of lamp 51. The light from lamp 51 shines through a lens or other transparent member 59, which is held in a ring 60. The top of box I0 carries a screw-threaded shell 6| adapted to receive a screwthreaded projection 62 which is attached to ring 60 or forms an integral extension thereof. The projection 62 terminates in spring fingers 63 adapted to grip the lamp 51. This construction provides a simple means for inserting the lamp into box |0 or removing it when necessary. To insert the lamp 51, it is only necessary to force the bulb between the spring fingers 63. The extension 62 is then screwed into the shell 6| by turning the outer ring 60, which supposed to be knurled at the edge for easy manipulation. When the ring 60 is turned in, the lamp 51 turns with it and is screwed into socket 56. When the ring 69 is unscrewed, the lamp 51 is turned out of its socket at the same time.

I shall now describe Figs. 8-12, which show the mechanism in the radio receiver for operating the `tuning shaft in accordance with the position of pointer I8 on the control box ID. The tuning shaft 64 extends at right angles to the front panel 65 of the receiver and is supported by brackets 66 and 61, which are rigidly mounted on the base plate 68. Sinceit is the general practice at the present time to tune radio circuits by means of variable condensers, I have shown condenser plates 69 fixed on shaft 64 and condenser plates 10 which are held stationary in any suitable way. Sometimes all the tuning elements are mounted on a single shaft, but in certain designs of receivers the gangs of tuning condensers are mounted on separate shafts coupled for simultaneous operation. Nor it is necessary that the tun-` ing elements be mounted on shaft 64, for they may obviously be supported on one or more separate shafts operatively connected to shaft 64. The particular form, arrangement and mounting of the tuning elements are not important in connection with this invention, and it will therefore be understood that the shaft 64 represents broadly a movable member for adjusting the tuning elements of a radio receiver. The front end of shaft 64 carries a suitable indicator 1|, which is here shown as a semi-circular plate carrying the usual notations to identify the different broadcasting stations. The indicating marks on disk 1| are visible through an opening 12 in front panel 65.

Since tuning condensers are usually so conn structed that a half-revolution of the movable plates covers the whole tuning range from maximum to minimum capacity, I have provided means for automatically reversing the direction of shaft 64 at the end of each half revolution. A gear 13 fixed on shaft 64 meshes with a pinion 14 mounted on a spindle 15 which is rotatably supported in bearings 16 and 11. The rear bearing 16 is part of the upright bracket 61, and bearing 11 may be attached to the front panel 65. A second pinion 18 on spindle 15 meshes with a rack bar 19 projecting from a reciprocable frame 86. The rack bar 19 has a slot 8| for receiving a grooved roller 82 mounted on a pin 63, and the frame is supported between a pair of grooved rollers 84 mounted on pins 85. The pins 83 and 85 may conveniently be secured to the front panel of the receiver cabinet. The reciprocable frame 80 comprises an upper rack bar 86 and a lower rack bar 81. The rack bar 19 and frame 8|] may be cast, stamped or molded as a single piece either from metal or strong insulating material. An electric motor 88 has a driving shaft 89 provided with a worm or spiral pinion 99 arranged in permanent mesh with a worm gear 9| fixed on a rotary shaft 92. A bracket 93 projecting from the housing of motor 88 supports the shaft 92, which carries a haliI gear 94 arranged to operate between the rack bars 86 and 81, as best shown in Fig. 9.

Assuming that the half gear 94 always rotates in a clockwise direction (as viewed in Fig. 9), it is evident that when the gear teeth engage the lower rock. bar 81, the frame 89 is moved to the left a predetermined amount. During the engage'- ment of half gear 94 with the upper rack bar 85, the frame 89 is shifted an equal amount toward the right. The rack frame 8D and half-gear 94 are so constructed that for a half revolution of shaft 92 the frame is moved in one direction, and during the other half revolution of the shaft the frame is moved in the reverso direction. These reciprocations of frame 88 are communicated to the tuning shaft 64 through gear connections 19 18 and 14--'|3. The transmission ratios of these connections are so calculated that during each movement of frame 8|! the tuning shaft 64 is moved through full tuning range, which means from one end of dial 1| to the other. The reason why the indicator disk 1| is cut away at 95, as shown in Fig. l2 is to avoid such parts as would otherwise be in its path of movement. The speed reduction between the motor shaft 89 and the tuning shaft 64 is suflicient to cause movement of the latter at the requisite low speed, which may approximate the speed of hand tuning.

I prefer to include provisions for tuning the shaft 54 by hand without going through the motor driving connections. For this purpose the spindle 15 is mounted for axial movement in addition to its rotary movement. A spring arm 96 mounted on bracket 61 engages the rear end of spindle 15 and normally holds the same in forward position, as shown in Fig. 8. The front end of spindle 15 carries a knob 91 or other suitable finger piece for conveniently manipulating the spindle hy hand. A grooved collar 98 fixed on spindle 15 engages a pair of rollers 99 carried by one end of a lever |99, which is pivoted on a pin i9! supported on a suitable bracket |02. This bracket may conveniently be attached to the front panel 65 by screws |93 or otherwise (see Fig. 9). The Vother end of lever 69 terminates in a yoke |04 having rollers arranged to engage in the annu lar groove of a clutch ring |66. which is slidably and loosely mounted on shaft 92. A clutch member |91 fixed on shaft 92 is adapted to engage the slidable clutch ring |66 for coupling the latter to the shaft. The clutch ring |06 is connected to the half-gear 94, which therefore partakes of the slidable and rotary movements of the clutch ring. The parts S4 and |96 are in effeet a single member mounted loosely on shaft 92 and adapted to be connected to the shaft when clutch ring |69` is shifted into locking engagement with clutch member |01, as shown in Fig. l0. The teeth of the half gear 94 are sufficiently wide to maintain engagement with rack frame 80 in either position of clutch ring |06;

In rthe normal position of spindle 15 as determined by the spring arm Slt,V the clutch members I3 and |91 are held in locking engagement, so that the tuning shaft 64 is operatively connected to the driving shaft 89 of motor 88. When a person wants to tune the receiver by Yhand independently of the motor, the knob 91| is pushed in Vas far as it will go. The inward movement of spindle 15 is limited either by the pinion 12 strikingthe front face of bearing 1t, orA by the rear edge lilof knob gl'striking the front panel 65. The-spring arm 96 is of such iiexibility that it does not offer undue resistance to the inward movementof knob 91. It is clear from Fig. l that, when the spindle 15 is pushed in, the right end of lever lili) is rocked forwardly, so that the clutch ring |96 is moved out of engagement With clutch memberl itl and the half gear 92 is disconnected` from the motor shaft. When the hand knob -Gj'i is rotated while being held pushed in, the rotation lof spindle 15 is communicated to shaft 64 vthrough gear connection 1li-i3. At the same time the rack frame Btl and half gear Si'.v are reciprocated, but these movements are idle and offer no appreciable resistance to the rotation of spindle 1E.

It is necessary to connect the half gear 94 and rack frame B permanently to spindle 15 in order to maintain the same relation between those parts. For example, looking at Fig. 9, we see that the half gear 94| and rack bar 81 are in a midway position, and consequently the tuning shaft 6e must be in a. midway position with respect to the station dial 1|. This midway position of shaft 64 is indicated by the midway position 59 of the tuning elements 6&3. When the half gear Sii breaks connection with the lower rack bar 8l and is about to engage the upper rack bar 86, the

tuning shaft 64 is at one end of its range of movement and is ready to reverse its direction of rotation. This operative relation between shaft E4 and half gear 94 is maintained permanently, irrespective of whether the spindle 15 is turned by means of the hand knob 9i' or by the electric motor 88. As soon as the operator releases the knob S1, the spring arm 9S throws the spindle forward to normal position and locks the clutch members tilt-|81. The pinions 1li and 1B on spindle 15 are sufficiently wide to remain in mesh with their associated gear members in either position of the spindle.

An upright frame or panel |539 is secured at its lower end to a plate H0, which may be an integral part of bracket t1. An opening i 2 in panel |09 makes room for shaft Gt. The upper end of panel |99 carries a set of contact pieces i3, which may be small plates of brass or other good con ducting metal forced into peripheral slots H4, so that no separate fastening means is necessary. The supporting panel i639 is preferably of insulating material, like bakelite, so that no separate insulation is needed for the individual contacts I3. The radial arrangement of these contacts is such that each one represents a selected station. A lug or extension H5 on each contact ||3 provides means for easily attaching the necessary conductors. In the present instance there are ten contacts H3 to represent the ten stations marked A-K on the indicator of control box I0. The tuning shaft Sli carries an insulating hub or collar H6 onwhich a switch arm ||1 is mounted. A set-screw H8 (see Fig. 10a) locks the collar llt to shaft 55|. A ring HB of good conducting metal is rigidly mounted on the insulating huby I (i and is in permanent contact Y separate contact |34 from contact `|3|.

with a'brush or switch armies, which is sup.`

ported at one end on an insulated bracket or lug l2! projecting from panel |09. The' rotary switch arm ||1 is connected to ring H9 by screws |22,

so that these two partsare in permanent elec- I tric contact. The collector ring H9 may also be made as an integral hub of switch arm I1.. The free end of arm ||1 preferably terminates in a lateral oliset or nose |23 for engaging the contact pieces |3with pressure. If desired, these contact pieces may be mounted like the contact pieces 21 in Fig. 6, so that the radial switch arm ||1` snaps into firm engagement with contacts H3. The arm ||1 is preferably made of spring materia-1 to press the nose or lateral oiset |23 against the face of panel l I9 and contacts i3.

A bracket |24 attached to the rear side of panel |69 carries a solenoid coil` |25 which has a soft iron core |26. An arm or lever |21 is pivoted on a pin |28 projecting rearwardly from panel |09. If the lever 2l is non-magnetic, it is proe vided with an armature piece |29 arranged `to be attracted by the electromagnet |25|26 when the same is energized. A bracket' |39 on panel |99 carries a contact |3|, which may simply be the head of a bolt |32. Nuts |33 on the lower end or bolt |32 may be used as a binding post for a conductor. .An insulated contact` |34 mounted on lever |21 is normally held against Contact |3| by a contracting coil spring |35. The lower end of 'this spring is connected' to a pin |3E extending rearwardly from panel |99, and the upper end of the spring is attached at |31 to the pivoted lever |21. When the coil |25 is energized, the left end of lever |21 is raised to When the coil is de-energized, the spring |35 instantly closes the switch contacts |34 and V|3i. These contacts constitute a switch in the circuit of motor 88, as will presently be explained.

Fig. 13 is a diagram showing the circuit connections between the control box land the radio receiver. To facilitate the tracing of cir cuits I have differentiated the contacts 21 of the control box and the contacts H3 of the radio receiver by the suiiix letters A-K, which are supposed to represent ten different stations. The contacts 21A-21K are connected to contacts H3A-HSK by conductors |38A-|38K, respectively. A plug |39 adapted to be inserted in a house-lighting socket is connected to a pair of service leads |40 and IM. or" the control box is connected to the switch arm |1 of the radio receiver by a conductor |42, which is connected to main le The other main |40 is connected by a conductor |23 to terminal |44 of motor 88, and a conductor M5 connects main |413 to one side of theV solenoid coil |25. lf desired or found necessary, resistances |46 and |46 are inserted in the circuits of coilv |25 and motor B3 to cut down the voltage. The other side of coil |25 is connected by a conductor |41 to the rotary selector arm 43 of the control box. The signal lamp 51 is included in conductor M1 and may be shunted by a resistance |48 Vso as not to interfere with the operation of the tuning apparatus if the lamp should accidentally burn out. 'Ihe second motor terminal |9` is connected by conductor |50 to contact |34 which is mounted on the pivoted lever |21. The associa-ted contact |Il| is connected by a conductor |5| to the contact strip 3e of the control box lil. The Contact arm 52 in the control box is connected by a conductor |52 to the electric driving unit of a suitable loudspeaker |53, which is inA The switch arm 5|' dicated merely in a diagrammatic way at the bottom of Fig. 13. The other side of the loudspeaker circuit is connected by a conductor |54 to contact strip 33. When the switch members 33 and 52 are in engagement, the operating circuit of loudspeaker |53 is closed. This condition obtains, as previously explained, when the push button 20 is in normal raised position. When the button is pushed down, the switch 33-52 is opened and the loudspeaker is silent.

Let us suppose that the pointer I8 of control box I has been turned to station E, as shown in Fig. l. The switch arms 43, I and 52 will then be in the position shown in Fig. 13. Nothing happens by the mere rotation of knob I6 to adjust the pointer I8, because the circuit of motor 88 remains open and the tuning shaft 64 is not operated. When the button 20 is pushed down after station E has been selected by pointer I8, the switch arm 43 engages contact 21E and switch arm 5| engages contact strip 36, whereby the motor circuit is closed as follows: Starting with service main |40, conductor |43, through the windings of motor 88, conductor |50, across the closed contacts |34-|3|, conductor |5|, across the closed contacts 36-5I, conductor |42 and return lead |4|. The energized motor now operates the tuning shaft 64 through the transmission connections previously described in detail. The shaft 64 is rotated in one direction or the other until the arm |I1 fixed on the shaft engages contact ||3E. When this happens, the circuit of coil |25 is closed as follows: Starting with service main |40, conductor |45, coil |25, conductor |41, switch arm 43, conductor |38E, contact II3E, switch arm ||1, conductor |42 and return lead |4|. When coil |25 is energized, it pulls the adjacent end of lever |21 down and abruptly pulls Contact |34 away from contact |3|, so that the motor circuit is interrupted and shaft 64 remains in tuning position. If necessary or desirable, a brake may be used to stop rotation of the motor shaft instantly when switch |3I-I34 is opened. The signal lamp 51 lights up when coil |25 is energized to inform the operator that the shaft 64 is in tuning position for the selected station. As soon as the operator receives the signal from lamp 51, he releases the push button 20 which opens the motor switch 36-5I and also breaks the circuit of coil |25 by raising the switch arm 43 away from contact 21E. The electric motor 88 and switch-operating coil |25 do not therefore consume any current after the desired station has been tuned in. Since the loudspeaker switch 33-52 remains open during the operation of shaft 64 by motor 88, the loudspeaker is silent during the tuning operation. As soon as the button 20 is released, the switch 33-52 is closed and the loudspeaker is in operative condition to reproduce the broadcast reception. In a simpler form of my invention, the signal lamp 51 and the loudspeaker switch 33- 52 may be omitted from the control box I0.

The circuits described in the preceding para- :graph for station E are the same for any one of the other stations marked on the indicator of control box I0, except that the circuit of coil |25 is closed only when the arms 43 and ||1 indicate corresponding contacts. For example, when pointer I8 is moved to select station B and button 28 is pushed down` the connected switch arm 43 engages contact 21B and the shaft 64 is stopped in tuning position for station B as soon as the rotary switch arm ||1 engages contact II3B. This explanation also applies to each of the other stations. A person may sometimes want to get a station not included in the ten stations marked on control box I0. In that case it is only necessary to move pointer I8 into position I8 (see Fig. 1) opposite the notation Any Station. the pointer is in position I8', the switch arms 43, 5| and 52 are in position 43', 5| and 52', respectively (see Fig. 13). In other words, the switch arm 43 is out of operative relation to contacts 21, but the other two switch arms 5| and 52 are still in alignment with the associated contact strips 36 and 33. When the button 20 is pushed down after the pointer has been moved to position I8', the motor switch 36-5I is closed and the tuning shaft 64 is operated until the desired station is received, whereupon the button is released. During this tuning operation it is necessary to keep the loudspeaker circuit closed, so that a person can hear each station as it crosses the tuning point during the rotation of shaft 64. This is accomplished by providing the contact strip'33 with a return extension 33 at the bottom, as shown in Fig. 5. When the button 20 is pushed down, the switch arm 52 engages the return extension 33 so that the loudspeaker switch 33-52 remains closed. The tuning shaft 64 operates at suflicientlylow speed to enable a person to hear the kind of programs sent out by the different stations.

In the modification of Figs. 14-17, the knob I6 and push button 20 of Fig. 2 are replaced by a single knob |55, which has both a rotary movement for selecting the desired station and an axial movement for closing the necessary circuits. All those parts that are common to the two constructions shown on sheets I and 5 are indicated by the same reference numerals to avoid needless repetition of description. The knob |55 is preferably an integral projection of a molded insulating piece |56, which is extended to form a thin semicircular disk |51. I have assumed that the control box |0 of Fig. 14 has five contacts 21 for tuning in five selected stations. Consequently, the

disk |51 is provided with five indicating marks |58 which represent stations A-E. The top ofv box I0 has a sight opening |59 through which the station indicia on disk |51 are visible. In Fig. 14, for instance, the knob |55 is turned for tuning in station C. The switch arm 43 is attached to a. radial extension or lug |60 below the indicator disk |51. The other two switch arms 5| and 52 are secured to lateral extensions |6I and |62 of a hollow hub or sleeve |63 projecting from part |56. The lower end of hub |63may engage in an annular recess I 64 for guiding the movements of knob |55 and all parts carredthereby. An expanding coil spring |65 arranged within sleeve |63 normally holds the knob |55 and its connected members in raised position, exactly as described in connection with the push button 20'in Fig. 2. A circular depending flange |66 in the top of box 0 extends into an annular groove |61 at the base of knob |55 and acts as an upper bearing for the latter. At the same time, the engagement of ange 66 in groove |61 limits the upward movement of knob |55 under the action of spring |65.

it is easily grasped by the fingers for rotary movement, and it may have a central depression |68 to facilitate the operation of the knob as a push button. The circuit diagram of Fig. 13 applies fully to the control box of Figs. 14-1'1. To bring in a station not represented by the notations on disk |51, the knob |55 is turned until the indicator line |69 is opposite the point |10 of windowv |59.

When the knob |55 is then pushed down, the same- When The projecting end of knob is so shaped that y :operation takes-place that was described in connection with push button 20when'the pointer |8 is in .position il 8 Figs. `18-20 illustrate a modification in-which the stationary contacts i3 4and the rotary switch'arm ||1 of the radio receiver are replaced byaset ofdisks `|1| fixed on the tuning shaft 64 and :carrying .each a contact 'i12 arranged to `cDnnect a pair of switch arms i 13| 1d. vAll parts common to the diagrams of Figs. 13 and ,18 are indicated .by the small reference numerals to avoid needless repetition of description. While Fig. :13 shows ten different stations which are automatically tuned in, Fig. 18 has been purposely simplified Vby using only ve stations A-E. For ldistinction the tuning disks I1! are diiferentiated by the suix letters A--E, and the same applies `to the different pairs of switch arms U13-H4. The individual contacts .21A- 21E are connected to'switch arms 2| 14A-INE by conductors |1.5A|15E, respectively. One side of coil `|25 is connected to switch arm 5| by a conductor |16 ywhich is connected to service lead MI. The other side of coil |25 is connected lby a cony ductor |11 to switch arms |13A-|13E, which are connected in parallel to that conductor. The signal lamp 51 is vconnected-in series with coil |25, but it may be omitted if desired. The motor terminal |44 is connected to switch arm 43 by a vconductor |18. The tuning disks 11| in Fig. 18

areshown in face View side -bysida but in actual practice they are mounted on shaft '94 as close together as mechanical conditions permit. A suitable lmounting for disks |1i is illustrated in Figs. 19 and 20. The switch arms |13 and |14 may be mounted on a common bar |19 secured to a Abracket |813.

Still referring to Fig. 18, the contacts |12 on disks |1| are arranged in such angular relationship that each contact connects the associated switch arms |13-I14 vwhen the station represented -by that contact is in tune. Let us suppose that we wish to bring in station C. If the control box of Fig. 1 `is used, the pointer I8 is turned to the indicating line C; .and if the control box of Fig. 14 is used, the knob |55 is turned until the C mark shows centrally through thewindow |59. When the tuning button 2B orv knob |55 is pushed down,

the circuit of motor 38 in Fig. 18 is closed' as follows: Starting with service lead |46, conductor |18, through the windings of motor 88, conductor |50, across the closed switch contacts ld-HH, conductor |51, through the closed switch 36-51, conductor |16 and the return lead MI. The'tuning shaft Stand disks |1| are rotated until the contact |12 of disk |1|C connects the associated switch arms H3C-IMC. The circuit of coil |25 is now closed as follows: Main |48, conductor |13, switch arm 43, contact 21C, conductor |150, across the closed switch IMC-|130, conductor |11, lamp 51, coil |25, conductor |16 and return lead IM. The energizing of coil |25 abruptly opens the switch |,3i-l34, so that the motor circuit is interrupted and the shaft G4 stops in tuning position for the selected station C. The circuits for any one of the other stations are traced in a -similar manner, as will be understood without the need of further detailed description.

Figs. 21 and 22 show a simplification of the control box illustrated on the first sheet of the drawings." -Here the sleeve 31 of knob |6 carries a contact ring or collar |8| which'may be screwed on or held in place by a set-screw |82. A hole |83 inthe side of box Hl permits the insertion of a screw-driver for tightening the screw |82. The

switch arm 4S isattached to the'underside of vcollar |8| by screws 1.84, or otherwise. The free end of arm 43 wipes over the top oi bridge piece -25 and vsnaps into engagement with the contacts 21 whenever it cornes into alignment with one of them. An insulating washer E on sleeve '31 'engages the lower edge of a depending flange i185 on the ltop of box ||l` to prevent axial movement of knob 4|65 and at the same time insulate the contact ring lill from the sheet metal cover of the box. The lowerY portion of push button .2D passes through a hollow boss |31 on base l2 and rests on the free end of a spring arm |88, which is attached to the base byV screws `89 or otherwise. One of these screws may be used as a binding post for a conductor. When the button 2l) is Vpushed down, the free end of switch arm |88 engages a fixed contact ist suitably mounted on base i2. An 'insulating post |9| projecting from base l2 vcarries a spring arm 592 arranged in permanent contact with the metal 'ring iI of switch arrn 43. It will not be necessary to show the diagram of circuit connections for the control box of Figs. 21 and 22, because substitution of vthis box in Figs. 13 and 18 is so obvious as to require no detailed description. `The switch |38- |9l of Figs. 21 and 22 takes the place of switch 35i-5| in Figs. 13 and 18. The lamp 51 and vloudspeaker switch 33-52 of Figs. 1.3 and 18 have been omitted in the control box of Figs.21 and 22, but they may be added if desired.

Still another form of control box embodying certain features of my invention is shown in Figs. 23--26, where the selector arm 43 is operated by means of a button i213, which is attached to the arm through a stem |54. The switch arm 43 is rotatably mounted on a pin |95 which is screwed into a central post |92 of base plate l2. The .stem .|94 ofY button HB3 extends through a semi-circular slot 191 in the top of box i0, and a pointer |98 on button |93 moves over a scale |99which consists of radial lines representing nine different stations marked A-J. A second switch arm 290 in the control box is connected with switch arm 43 by an insulating piece 20|, so that the two arms move down and up as a unit. These two arms are connected to a pair of insulated metal rings or collars 202 and 203 respectively, which are rotatably mounted on 'pin andinsulated therefrom by a bushing 2M of bakelite, hard rubber and the like. An insulating post 2&5 projecting from base i2 carries a pair of spring arms 2536 and 201 which are in permanent Contact with the insulated rings 202 and 223 respectively. Below the free end of switch arm 206 is a contact strip EBS mounted on a lateral extension or shelf 2119 of bridge 25. The bushing 2014 has a key 2li! projecting into aligned axial slots 2|! in contact rings 262 and 203, whereby the switchfarms 43 and 2W are locked together for simultaneous rotation. 1f the insulating lug 20| Vis secured to both switch arms 43 and 220, the locking key 2|@ is not necessary. In Fig.24, the lug 20| is attached to the upper switch arrnk i3 by a screw Si|2and its lower end need only touch the switch arm 2G!! if locking key 2i@ is used. Any other-practical arrangement may be employed for mounting the switch arms 43 and 2Go so that they operate as a unit both for rotation and for vertical movement.

Still referring to Figs. 23-25, kwhen a person wants to tune in a particular station, he moves the button i193 until the pointer 19B is opposite the indicating mark of the station wanted.- The button |93 vis then pushed down,fwhereupon the switch arm 43 engages the proper Contact 21 and at the same time the lower switch arm 200 engages the contact strip 28 to close the circuit of motor S8. It is not believed necessary to show a separate circuit diagram for the control box oi Figs. 23-25, because the substitution of this box in Figs. 13 and 18 is evident to those skilled in the art. I need only say that the motor switch 20D- 208 of Fig. 24 takes the place oi the motor switch 38--51 of Figs.v 13 and 18. The switch arms 43 and 230 are made of spring metal, so that they are pushed down without undue resist-- ance. rIhis downward movement need be but a small fraction of an inch. The normal tension of spring arms 43 and 200 holds them in open position and restores them to normal raised position when the button |93 is released.

Attention is called to the fact that no highvoltage wires are in the electric cable that connects the control box with the radio receiver. The small motor 88 and coil i25 operate on such low voltage that no arcing occurs at the switch contacts in the control box. The latter can be made small and compact, because it contains no solenoids or other parts that take up much space. The control mechanism in the receiver cabinet is comparatively simple. In the basic aspect oi my invention, any practical means may be employed for reversing the tuning shaft at each end oi the dial. For example, a reversing switch for the motor may be used, but personally I prefer to have the motor shaft run always in the same direction and to reverse the transmission connections.

Although I have shown and described certain speciiic constructions, my invention is not limited to the details set forth. Changes and modifications will probably occur to others without departing from the scope of the invention as defined in the appended claims. I might add that the drawings have not been made to accurate scale and are not therefore to be regarded as shop drawings in which every minute part has been carefully calculated. I have purposely exaggerated some of the parts to make the drawings as clear as possible.

I claim as my invention:

1. In radio tuning apparatus, a remote control box having a series of electric contacts representing each a selected station, a rotary switch arm normally out of engagement with said contacts and movable axially into engagement with a selected contact, a normally open motor switch in said box, a manually operable member for closing said switch arm against any one of said contacts and at the same time closing said motor switch, and spring means for automatically restoring said switch arm and motor switch to normal position upon the manual release oi said member, in combination with a radio receiver having adjustable tuning means, an electric motor or operating tuning means, said normally open switch being connected in the circuit of said motor, and control mechanism operatively connected with said contacts tostop said motor when said timing means has tuned in the station represented by the particular contact which said switch arm engages when the motor switch is closed.

2. In radio tuning apparatus, a remote control box having a series of electric contacts representing each a selected station, a rotary switch armv normally out of engagement with said contacts and movable axially into engagement with a selected contact, a normally open motor switch in said box, a push button on top of said box for closing said switch and moving said switch arm axially into engagement with the selected contact, and means whereby said motor switch and station-selecting switch are instantly opened by the manual release of said push button, in

combination with a radio receiver having ad'-A justable tuning means, an electric motor for operating said tuning means, said normally open switch being connected in the circuit of said motor, and control mechanism operatively connected with said contacts to stop said motor when said tuning means has tuned in the station represented by the particular contact which said switch arm engages when the motor switch is closed.

3. In radio tuning apparatus, a remote control box having an adjustable iinger piece on top, means whereby said finger piece is depressible in any adjusted position, said finger piece being normally held in raised position, a series of switch contacts in said box representing selected stations, a switch member connected to said iinger piece and movable therewith to engage any one of said contacts when the linger piece is pushed in, and means whereby the manual release of said finger piece instantly disengages said switch member from the selected contact, in combination with a radio receiver having adjustable tuning means, an electric motor for operating said tuning means, and electric control mechanism operatively connected with said stationselecting contacts and adapted to stop said motor when said tuning means has tuned in the station represented by the particular contact which said switch member engages, said mechanism including a plurality of separately operable circuits connected each to one oi said contacts and an electromagnetic switch automatically energized upon the closing of any one of said separate circuits to open the motor circuit, each of said separate circuits being automatically closed when the station represented by the selected Contact is in tune, the manual release of said lnger piece automatically opening the closed circuit.

4. In radio tuning apparatus, a remote control box containing a normally open motor switch and a normally closed loudspeaker switch, manually operable means for simultaneously closing said motor switch and opening said loudspeaker switch, and connections whereby the manual release of said switch-operating means instantly restores said switches to normal condition, in combination with a radio receiver having adjustable tuning means and a loudspeaker, an electric motor for operating said tuning means, said motor switch and said loudspeaker switch being connected respectively in the circuit of said motor and in the circuit of said loudspeaker, and means whereby the operation of said manual means automatically causes said motor to tune in a desired station by adjusting said tuning means, the loudspeaker circuit remaining open until said manual means is released, whereupon the loudspeaker switch is automatically closed and the motor switch is opened.

5. In radio tuning apparatus, a remote control box having a series of electric contacts representing each a selected station, a rotary switch arm movable into engagement with a selected contact, a normally open motor switch in said box, manually operable means for closing said switch, a normally closed loudspeaker switch in said box, connections whereby said loudspeaker switch is opened when said motor switch is closed,

and means whereby the manual release of said switchecperating means instantly restores said motor switch and loudspeaker switch -to normal condition, in combination with a radio receiver having adjustable tuning means and a loudspeaker, an electric motor for operating said tuning means, said motor switch and said loudspeaker switch being connected respectively in the circuit of said motor and in the circuit of said loudspeaker, electric control mechanism operatively connected with said contacts to stop said motor when said tuning means has tuned in the station represented by the particular centact which said switch arm engages when the motor'switch is closed, the loudspeaker circuit remaining open until said manual means is released, whereupon the loudspeaker switch is automatically 'closed and the motor switch is opened.

6. In radio tuning apparatus, a remote control box having a pivotally mounted finger piece, an indicating device movable with said finger piece, a iixed indicating device on top of said box, one of said indicating devices bearing marks tol designate certain selected stations, a series of switch contacts in said box representing said selected stations, a switch member operated by said finger piece to engage any one of said contacts, and means whereby the manual release of said ringer piece instantly disengages said switch member from the selected contact, in combination with a radio receiver having a tuning shaft rotatable in opposite directions through a predetermined arc, an electric motor lfor operating said shaft in either direction through its arc of travel, a plurality of separately operable electric circuits connected each to one of said station-selecting contacts, connections whereby any one of said separate circuits is closed when said shaft is in tuning position for the station represented by the engaged contact, said connections including contact means synchronously movable with said shaft, a normally closed switch in the motor circuit, electromagnetic means automatically energized when said shaft is in selected tuning position for opening said motor switch, and means whereby said motor switch is automatically closed when said finger piece is released.

-'7. In radio tuning apparatus, a remote control box having a series of .electric contacts represeating each av selected station, a rotary switch arm associated with said contacts and normally held spaced therefrom, whereby said arm may be rotated without engaging said contacts, a nor-A mally open motor switch in said box, manually operable means for moving said arm into engagement with a selected Contact and at the same time closing said motor switch, and means whereby the manual release of said switch-operating means instantly opens said switch arm and motor switch, in combination with a radio'receiver having adjustable tuning means, an electric motor for operating said tuning means, said normally open switch being connected in the circuit of said motor, and electric control mechanism operatively connected with said contacts to stop said motor when said tuning means has tuned in the station represented by the particular contact which said switch arm engages when Asaid motor switch is closed, said control mechanism including a second switch in the motor circuit in series with said rst motor switch, said second motor switch being normally closed and being automatically opened when said tuning means is in preselected tuning position, the re'.

box having a series of electric contacts representing each a selected station, a rotary switch arm associated with said contacts and normally held spaced therefrom, whereby said arm may y be rotated without engaging said contacts, a normally open motor switch in said box, a push button on top of said box for moving said arm into engagement with a selected vcontact and at the same time closing said motor switch, and means whereby the manual release of said push button instantly disengages said switch arm from the selected contact and opens the motor switch, in combination with a radio receiver having ad.- justable tuning means, an electric motor for operating said tuning means, said normally open switch being connected in the circuit of said motor, and electric control mechanism operatively connected with said contacts to stop said motor when said tuning means has tuned in the station represented by the particular contact which said switch arm engages when the push button is operated, said electric control mechanism including circuits which are automatically opened upon release of said push-button.

9. In radio tuning apparatus, a remote control box having a pivotally mounted finger piece on top, means whereby said iinger piece is depressible, said finger piece being normally held in raised position, a series of switch contacts in said box representing selected stations, a switch member connected to said nger piece and movable therewith to engage any one of said contacts when the finger piece is depressed, a normally open motor switch in said box, means for closing said motor switch when said nger piece is pushed down, and means whereby the manual release of said nger piece instantly disengages said switch member from the selected contact and opens the motor switch, in combination with a radio receiver having adjustable tuning means, an electric motor for operating said tuning means, said normally open switch being connected in the circuit of said motor, and control mechanism operatively connected with said contacts t stop said motor when said tuning means has tuned in the station represented by the par.- ticular contact which said switch arm engages when the motor switch is closed.

l0. A radio receiver having variable tuning means, a rotary shaft for operating said tuning means, `said shaft being rotatable in either direction through a predetermined arc to cover the whole broadcasting range, an electric motor normally connected to said shaft for operating the same, means for controlling the operation of said motor to tune in any desired station, a rotary hand knob permanently connected to said tuning shaft for manually operating said shaft independently of said motor, and means controlled by said knob for uncoupling said motor from said shaft when the latter is turned by hand, said disconnecting means including a manually adjustable transmission member. Y

11. A radio receiver having variable tuning means, a rotary shaft for operating said tuning means, said shaft being rotatable in either direction through a predetermined arc to cover the whole broadcasting range, an electric motor normally connected to said shaft for operating the same, means for controlling the operation of said motor to tune in any desired station, a hand-op-` rable spindle connected to said shaft for actuating the same independently of said motor, a finger piece permanently connected to said spindle for manual operation thereof, and means controlled by said spindle for disconnecting the motor from the tuning shaft when the latter isoperated by the spindle, said means including a manually adjustable transmission member.

12. A radio receiver having variable tuning means, a rotary shaft for operating said tuning means, said shaft being rotatable in either direction through a predetermined arc to cover the whole broadcasting range, an electric motor connected to said shaft for operating the same, means for controlling the operation of said motor to tune in any desired station, a hand-operable rotary spindle connected to said shaft for actuating the same independentlyy of saidl motor, a finger piece permanently connected to said spindle for manual operation thereof, said spindle being also mounted for arial movement, and a clutch controlled by the axial movements of said spindle for disconnecting the motor from the tuningv shaft when the latter is operated by the i spindle.

struct the rotary movement ofsaid arm throughV a predetermined arc in either direction, a single electric motor for operating said shaft in alter.- nately opposite directions, means for automatically reversing the rotation of said shaft at each end of its arc of travel, and selectively operable means for automatically opening the motor circtut when said arm engages a predetermined Contact, whereby said shaft stops in selected. position.

14., The combination of a rotary shaft, a single electric motor for operating said shaft in opposite directions through a predetermined arc, a set of circularly arranged contacts representing eachA a selected position of said. shaft, a pivotedv switch arm movable with said shaft and arranged to engage said contacts, means for automatically reversing the rotation of said shaft at each.

end of its arc of travel, a remote control devicehavinga rotary switch arm, a set'of contacts arranged to be engaged by said last-mentioned switch arm to select any position of said shaft, and means whereby the motor circuit is automatically opened to stop said shaft when said switcharms engage corresponding contacts, said last-mentioned means beine operative irrespective of the angular position from which said shaft starts to rotate.

i5. The combination of a rotary shaft, a set of circularly arranged contacts representing each a selected position of said shaft, a pivoted switch arm movable with said shaft and arranged to i engage said contacts, a single electric motor for operating said shaft in opposite directions through a predetermined arc, means for automatically reversing the rotation of said shaft at each end of its arc of travel, a remote control device having a movable finger piece to select any one of said stations, connections controlled by said linger piece for automatically opening the motor circuit when said arm engages a predetermined contact, whereby said shaft stops in selected position, and means whereby said circuit-A opening connections are operative irrespective of the angular position from which said shaft starts to rotate.

16. The combination of a shaft rotatable in opposite directions through a predetermined arc, a single electric motor for operating said shaft in both directions, a set of electric contacts representing each a selected position of shaft, a switch movable with said to engage said contacts, ineans for automatically reversing the movement of said shaft and switch arm at each end of their path of travel, a remote controldevice having a set of contacts electrically connected individually to said first-mentioned contacts, a manually operable switch arm carried by said device and movable into engagement with any one of the second set of contacts for selecting a position in which said shaft shall stop, and means whereby the motor circuit is automatically interrupted when` the two switch arms engage a pair of connected contacts, circuit-interrupting means being operative irrespective of the angular position from which said shaft starts to rotate.

l?. The combination of a rotary shaft, a set of electric contacts representing each a selected position of said shaft, a switch arm rotatable with said shaft and arranged to engage said cont cts, a single electric motor connectedV tc said shaft for operating the same in alternately opposite directions through predetermined arc, means whereby the rotation of said shaft is automatically reversed at each end of its arc of travel, a normally closed switch in the motor circuit, an electroinagnet adapted when energized to open the motorswitch, said-electioinagnet comprising. a coil, a remote control device having a set of contacts electrically connected individually to said first-mentioned contacts, and manually operable means carried by said. control device for selecting anyone of the second set of contacts toclose the circuit of said coil and thereby open the motor circuit when said switch arm engages the particular contact which corresponds to t1 e selected contact of said control device.

i8; The combination of a rotary shaft, a sin-- gle electric motor for operating said shaft in opposite directions through a predeterminedV arc, switch mechanism associated with said shaft to control its operation, said mechanism including a set of stationary contacts and also contact means movable with said shaft to engage said contacts individually, means for automatically reversing the rotation of said shaft at each end of its arc of travel, a remote control device having a set of selector contacts elec rically connected individually to said first-mentioned contacts, a manually operable switch arm carried by said device and movable into engagement with any one of said selector contacts for selecting a position in which said shaft shall stop, and connections whereby the motor circuit is automatically interrupted by said movable contact means engaging the particular tuning contact which is electrically connected to the selector contact engaged by said svitch arm in the control box, said motor-stopping connections being operative irrespective of the angular position from which said shaft starts to rotate.

19. In radio tuning apparatus, a remote control box containing a loudspeaker' switch, stationselecting means in said boX, and a spring-pressed push buttonon said box for operating said switch and station-selecting means, the manual release of said'push button instantly restoring the same to normal position, in combination with a radio receiver having adjustable tuning means and a loudspeaker, mechanism for operating said tuning means, operative connections between said station-selecting means and said mechanism whereby the operation of said means by said push button automatically causes said mechanism to adjust said tuning means for the selected station, means for connecting said switch in the circuit of said loudspeaker, and means whereby the operation of said push button renders the loudspeaker inoperative, the release of said push button automatically operating said switch to render the loudspeaker operative.

20. In radio tuning apparatus, a radio receiver having adjustable tuning means and a loudspeaker, means for operating said tuning means, in combination with a remote control box containing a normally closed switch connected in the circuit of said loudspeaker, manually controllable station-selecting mechanism carried by said box and operatively connected with said operating means to adjust said tuning means for a selected station, said mechanism including an adjustable nger piece, means for automatically opening said switch when said mechanism is in operative position to render said loudspeaker inoperative during the tuning operation, and means whereby the operators release of said nger piece instantly restores said switch to normal condition and renders said loudspeaker operative.

2l. In radio tuning apparatus, a remote control box having a nger piece mounted for independent rotary and axial movements, a series of normally open switch contacts in said box representing certain selected stations, means whereby the rotary adjustment of said finger piece selects one of said switch contacts for operation, means `whereby the axial movement of said finger piece closes the selected Contact, and means whereby the operators release of said linger piece instantly opens said closed contact, in combination with a radio receiver having an adjustable tuning shaft, an electric motor for operating said shaft, a plurality of separately operable electric circuits connected each to one of said station-selecting contacts, connections whereby any one of said separate circuits is closed when said shaft is in tuning position for the station represented by the engaged contact, said connections including contact means synchronously movable with said shaft, a normally closed switch in the motor circuit electromagnetic means automatically energized when said shaft is in selected tuning position for opening said motor switch, and means whereby said motor switch is automatically closed when said finger piece is released.

22. In radio tuning apparatus, a remote control boX containing a series of circularly arranged contacts which represent each a certain station, a rotary switch arm normally in a position Where it can not engage said contacts, means whereby said arm is movable into engagement with any one of said contacts after the arm has been rotatably adjusted to select a certain station, said means including a movable nger piece, and means whereby the manual release of said finger piece disengages said switch arm from the selected contact, in combination with a radio receiver having an adjustable tuning shaft, an electric motor for operating said shaft, a plurality of separately operable electric circuits connected each to one of said station-selecting contacts, connections whereby any one of said separate circuits is closed when said shaft is in tuning position for the station represented by the engaged contact, said connections including contact means synchronously movable with said shaft, a normally closed switch in the motor circuit, electromagnetic means automatically energized when said shaft is in selected tuning position for opening said motor switch, and means whereby said motor switch is automatically closed when said nger piece is released.

23. In radio tuning apparatus, a remote control boX containing a series of circularly arranged contacts which represent, each a certain station, a rotary switch arm normally in a position where it can not engage said contacts, means whereby said arm is movable into engagement with any one of said contacts after the arm has been rotatably adjusted to select a station, said means including a manually operable member, a. normally closed loudspeaker switch in said box, and means for holding said switch open as long as said arm engages one of said contacts, the manual release of said member instantly closing said switch and disengaging said arm from the selected Contact, in combination with a radio receiver having adjustable tuning means and a loudspeaker, electric mechanism for operatingA said tuning means, operative connections between said mechanism and said contacts whereby the operation of said member to close said switch arm against a selected one of said contacts automatically causes said mechanism to adjust said tuning means for the selected station, and means for connecting said loudspeaker switch in the circuit of said loudspeaker, so that the latter remains inoperative as long as said manual member is held in operated position, the release of said member automatically rendering the loudspeaker operative.

24. In radio tuning apparatus, a remote control boX containing a normally closed loudspeaker switch, a manually adjustable station-selecting member carried by said box, a plurality of electric contacts arranged to be selectively engaged by said member and representing each a certain station, said member being also adapted to occupy a universal tuning position independent of said contacts for selecting any station within the broadcasting range, means for automatically opening said switch when said member engages one of said contacts, means whereby said switch remains closed when said member is in said universal tuning position, and a normally open motor switch in said box adapted to be closed when said member is in engagement with any one of said contacts or in its universal tuning position, in combination with a radio receiver having adjustable tuning means and a loudspeaker, an electric motor for operating said timing means, electric control mechanism between said motor and saidv tuningv means to control the operation of the motor in accordance with a station selected by said member, operative connections between said mechanism and said contacts whereby the engagement of a selected contact by said manually adjustable member causes said mechanism to stop said motor when the tuning means is in position for the selected station, means for connecting said loudspeaker switch in the circuit of said loudspeaker, means for connecting said normally open motor switch in the circuit of said motor, which is thereby energized when said member is in operated position, and means for automatically rendering said control mechanism inoperative when said member is moved to universal tuning position.

25. In radio tuning apparatus, a remote control box containing a series of circularly aril O ranged contacts which represent each a certain station, a spring switch arm mounted at one end for rotary movement and normally held out of engagement with said contacts, a finger piece attached to said arm near its free end for turning the arm and also pushing it toward said contacts, said box having an arcuate slot through which said finger piece extends, a second rotary switch arm movable with said first switch arm, and an arcuate contact member arranged to be engaged by the second ari-n in any rotatably adjusted position of the latter when said finger piece is pushed in, in combination with a radio receiver having adjustable tuning means, an electric motor for operating said tuning means, electric mechanism for controlling the operation of said motor, operative connections between said mechanism and said contacts whereby the operation of said finger piece to push said first-mentioned switch arm against a selected contact automatically causes said mechanism to stop said motor when the tuningk means is in position for the selected station, and means for connecting said second switch arm and said arcuate contact member in the circuit of said motor, which is automatically energized when said finger piece is pushed in.

26. The combination of a shaft adapted to rotate in opposite directions through a predetermined arc, a switch arm movable synchronously with said shaft, a series of contacts arranged to be engaged by said arm and representing certain preselected positions of said shaft, a single electric motor for operating said shaft in either direction, means for automatically reversing the rotation of said shaft at each end of its arc of travel, manually controlled means for selecting any position of said shaft, and means for automatically opening the motor circuit when said switch arm engages a contact which represents the selecte-d position of said shaft.

27. The combination of a shaft adapted to rotate in opposite directions through a predetermined arc, rotary contact means operated synchronously with said shaft, a series of contacts arranged to be engaged by said contact means when the shaft is in certain preselected positions, a single electric motor for operating said shaft in either direction, means for automatically reversing the rota-tion of said shaft at each end of its arc of travel, a manually operated member for selecting any one of said positions of the shaft, and means oonjointly controlled by said member and said Contact means for opening the motor circuit when the shaft is in selected position.

28. In electric remote control apparatus, the combination of a rotary shaft adapted to occupy any one of a plurality of angular positions, a remote control device having a rotary knob which is also depressible like a push button, means whereby the manual release of said knob instantly restores it to normal position, a pointer movable with said knob over an index on which certain selected positions of said shaft are marked, normally open switches in said device representing the shaft positions noted on said index, said switches being selected for operation by the rotary movements of said knob, a single electric motor for operating said shaft in opposite directions through a predetermined arc, means whereby the pushing in of said knob sets the motor in, operation until the selected position of said shaft is reached, means for automatically reversing the direction of rotation of said shaft at each end of its aro of travel, and means whereby the circuit of said motor is automatically opened when said shaft is in the angular position selected by said knob.

29. In radio tuning apparatus, a remote control box, a single rotary knob which is also depressible like a push button, means whereby the release of said knob instantly restores it to normal position, a pointer movable with said knob over an index on which certain selected stations are marked, normally open switches in said box representing the stations on said index, said switches being selected for operation by the rotary movements of said knob, in combination with a radio tuning shaft, a single electric motor for operating said shaft in opposite directions through a predetermined arc, means whereby the pushing in of said knob sets the motor in operation until the selected station is in tune, connections whereby the motor automatically stops when said shaft is in tuning position for a selected station, means operated by depressing the knob when in a certain rotatably adjusted position for closing the motor circuit independently of said switches, the motor circuit being interrupted when the knob is released, and means whereby the rotation of said shaft is automatically reversed at each end of its arc of travel while the knob is held depressed in said certain position, so that any broadcasting station can be tuned in by the operation of said single knob without regard to said index on the control box.

30. A radio receiver having adjustable tuning means, a loudspeaker, and an electric motor for operating said tuning means, in combination with a normally open switch in the motor circuit, a

normally closed switch in the loudspeaker circuit, each switch including a movable member, and a singie spring-pressed finger piece mechanically connected to both of said switch members for simultaneously actuating said members to close the motor switch and to open the loudspeaker circuit, whereby the loudspeaker is silent when said motor is energized to operate said tuning means, said spring-pressed finger piece when released returning automatically to normal position to open said motor switch and to close said loudspeaker switch.

3l. Remotely tuned radio apparatus comprising the combination of a radio receiver having adjustable tuning means and a loudspeaker, an electric motor for operating said tuning means, a normally open switch and a normally closed switch located remotely from said receiver, means for connecting said normally open switch in the circuit of said motor, means for connecting said normally closed switch in the circuit of said loudspeaker, a single hand-operable member for closing the motor switch and at the same time opening the loudspeaker switch, the closing of said motor switch causing the electric motor to operate said tuning means to bring in a desired station, the opening of said loudspeaker switch causing the loudspeaker to remain silent during the tuning operation, and spring means for holding said member in normal position, whereby said loudspeaker switch is automatically closed upon manual release of said member to render the loudspeaker operative for the tuned-in station.

32. In electric remote control apparatus, the combination of a shaft rotatable to occupy any one of a plurality of predetermined angular posi.- tions, an electric motor for operating said shaft, a series of electric contacts remote from said shaft and representing each a different angular position of said shaft, a rotary switch arm normally spaced from all of said contacts and movable axially into engagement with a selected contact, said switch arm when in normal position being radially adjustable into alignment with any one oi said contacts, a, normally open switch in the circuit of said motor, a movable ringer piece for closing said motor switch and axially moving the radially adjusted switch arm into engagement with a selected contact, means whereby said motor switch is closed by the operation of said finger piece irrespective of the radial position of said switch arm, spring means for normally holding said.v iinger piece in circuit-opening position, whereby the release of said nger piece automatically returns said switch arm and said motor switch to open position, and electric mechanism associated with said shaft and operatively connected with said contacts and switch arm for automatically stopping said shaft in the angular position represented by the particular contact which said switch arm engages, said mechanism including a second switch in the motor circuit in series with said first motor switch, said second motor switch being normally closed, said control mechanism also including electromagnetic means automatically energized when said shaft is in' preselected position to open the second motor switch, the automatic return of said switch arm to open position upon manual release of said finger piece causing saidV electromagnetic means to be de-energized and thereby close the second motor switch, the automatic opening of the first motor switch upon release of said nger piece holding the motor circuit open and thereby causing the shaft to remain in preselected angular position.

33. A radio receiver having a rotary tuning shaft, an electric motor for operating said shaft, and a loudspeaker, in combination with a remote control device having a single iinger piece mounted to have a plurality ci different operative movements, means for controlling said motor by certain movements of said finger piece, and means for controlling a circuit of said loudspeaker by other movements of said finger piece.

34. Remote-control apparatus for radio receivers, comprising a radio receiver having a rotary tuning shaft, an elect-ric motor for operating said shaft, a loudspeaker, and electric control mechanism for said motor to stop said shaft in selected tuning position, said mechanism including a plurality of separately operable circuits representing each a selected station, in combination with a remote control box having a plurality of stationselecting contacts connected each to one of said circuits, a rotary hand knob on said box mounted alsoy for limited axial movement in any rotatably adjusted position, spring means for normally holding said knob pushed out, contact means in said box normally out of engagement with said station-selecting' contacts to hold said circuits' open, whereby said knob is normally rotatable to station-selecting position without operating said control mechanism, the inward axial movement of said knob in station-selecting position automatically moving said contact means intov engagement with Ythe selected contact to close the corresponding circuit and thereby energize said electric control mechanism, which stops said shaft in selected tuning position, means for operatively connecting said loudspeaker with said box, and normallyy open switch means in said box adapted to be closed by the axial movement of said knob for energizing said tuning motor when the knob is pushed in in any radially adjusted position.

35. A radio receiver having a rotary tuning shaft, an electric motor for operating said shaft, and a loudspeaker, in combination with a remote control device having a rotary knob Aadjustable axially to two operative positions and rotatable in either axialposition, means for controlling said motor by the rotary movements of said knob in one axial position, and means for controlling a circuit of said loudspeaker by the axial movements of said knob.

36. A radio receiver having an adjustable tuning shaft and mechanism for operating said shaft to any one of a plurality of preselected tuning positions, saidmechanisrn including an electric motor for driving said shaft, in combination with a remote control box containing a plurality of normally open switches, which include contact members mounted in circularly spaced arrangement and representing certain stations, a rotary stem in said box mounted also for axial movement, a hand knob on the outer end of said stem to operate the latter, spring means for normally holding said knob in raised position, the depressed knob when released being at once restored to normal raised position by said spring means, a station indicator movable with said knob, which is freely rotatable in raised position to select any desired station, said circularly spaced switch members remaining all in open-circuit condition as long as the knob is in normal raised position, means carried by said stem for automatically closing a preselected switch when the knob is pushed in after being turned to select a station, and electric connections between said switches and said mechanism whereby the electric motor is automaticallyenergized when the knob is pushed in to close a selected switch, said mechanism including means controlled by a closed switch for automatically stopping the tuning shaft in position for the station represented by the closed switch.

ADOLPH A. THOMAS.

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