US2088451A - Acoustic reproducing apparatus - Google Patents

Description

A. A. T'HoMAs 21,088,451

ACOUSTIC REPRODUGING APPARATUS July 27, 1937.

Filed oct. 7, 19:50 @sheets-sheet 1 TRACK sElLEc-ron v INVENTOR July 27,y 1937. A. A. THOMAS ACOUSTIC REPRODUCINGl APPARATUS Filed oct. '7, 1930 @sheets-sheet 2 v INVENTqR 1.3

, NN Y 9 sheets-sheet 3 Filed Oct. 7, 1930 INVENTOR lJly 27, 1937. -A. A. THQMAS 2,088,451

I ACOUSTIC REPRODUCING APPARATUS Filed Oct. 7, 1930. 9 Sheets-Sheet 4l una] i i u'l vINVENTOR July 27, 1937. A. A. THOMAS h ACOUSTIC REPRODUCING APPARATUS Filed OCT.. '7, 1930 9 Sheets-Sheet 5 INVENTOR July 27, 1937. A. A. THOMAS ACOUSTIC REPRODUCING APPARATUS 9 Sheets-Sheet 6 Filed 0012-. '7, 1930 INVENTOR 0MM/W July 27, 1937. A. A. THOMAS 2,088,451

ACOUSTIC BEPRODUC ING APPARATUS Filed OCb. '7, 1930 9 Sheets-Sheet '7 lNvENToR A lJuly Z7, 1937. A. A.v 'rHoMAs ACOUSTIC REPRODUCING APPARATUS Filed Oct. 7, 1930 9 Sheets-Sheet 8 l INVENTQR NWN NNN

July 27, 1937. A. A. THOMAS 2,088,451

ACOUST I C REPRODUC ING APPARATUS @ZQO EADIP l/"ILM VOLUME.

INVENTOR Patented July 2.7i, 1937 UNITED STATES PATENT OFFICE Radio Corporation of America,

New York,

N. Y., a corporation of Delaware Application October 7, 1930, Serial No. 486,985

6 Claims.

This invention relates to the art oi reproducing transmitted or recorded sound, and its `object is to provide a film-controlled phonograph of novel construction adapted to be combined with a radio receiver in a single cabinet.

My new phonograph mechanism employs a photographic lm on which the soiuid is recorded in a plurality of tracks running lengthwise of the lm in alternately opposite directions. The lo movement of the lm is automatically reversed at the end of each record track, and the machine automatically stops when the last track is played through. A rotary shutter is automatically operated at the end of each sound track i5 'to direct light rays through the next track. This shutter may also be adjusted by hand to bring any track into initial playing position when the lm carries several recordings that begin in different tracks. Each spool carrying a multiple- 23 record lm has marked thereon the title of each recording and the number of the track invwhich .it begins. The operator can select any piece on the lm for reproduction by simply moving a pointer to the desired number on a track indicator.

Although my new film-controlled phonograph is capable of use without a radio receiver, I prefer to combine the two in one cabinet, because certain mechanism is common to both devices.. qu Thus, the electric impulses produced by the phonograph are amplied through the same system and reproduced by the same loudspeaker as the broadcast waves picked up by the receiver. A switch on the cabinet enables the operator to change from radio reception to lm reproduction, and vice versa. I also provide a remote control box for the radio receiver and thc phonograph, so that either apparatus can be operated l at a distance from any convenient point. A in single electric motor drives the film shaft of the phonograph and also the tuning shaft of the receiver, but both shafts are never operated at the same time. I may also use the same motor to operate a volume-controlling device for pho- 47, nograph 'and broadcast reproduction.

The various novel features and practical advantages of my invention will be ciear from a detailed description of the accompany drawings, in which- Fig. 1 shows in perspective a combinatio radio-phonograph cabinet constructed in accordance with my invention;

Fig. 2 is a side view of Fig. l, with an outer panel of the cabinet broken away to show ecr- 55 tain parts inside;

(C1. 17e-100.11)l

2a is an enlarged face view of the trackselector knob and indicator;

Fig. 3 represents a top plan of the phonograph mechanism.

Fig. 4 is a front elevation on line 4--4 of Fig. 3;

Fig. 5 shows a transverse section on line 5--5 of Fig. 4;

Fig. 6 is a section on line 6--6 of Fig. 5; f

Fig. 7 is a transverse sectional View on line 7 1 of Fig. 3 to show certain details of the optical mechanism controlled by thesound film 8, 9, and 10 are sections on lines 85, 9-9 and iO--IIL respectively. of Fig. 7;

Figs. 11 and 12 (on Sheet 2) show details oi the switches controlled by the moving lm, these views being detached sections on lines I I-I I and I2--I2 of Fig. 3;

Fig. 13 is a diagram of electric circuits controlled by the phonograph film;

Fig. 14 is a diagram of combined operating circuits for the radio receiver and the lm phonograph, including the remote control connections for both devices;

. Fig. 15 shows a film spool bearing notations to identify the pieces recorded on the lm and the number of the track on which each recording begins;

Fig. 16 lis a plan view of my new remote con- Ytrol box with the cover removed, this view showingv the movable parts in position to control the o radio receiver;

Fig. 17 is similar to Fig. 16, except that the parts are in position to control the operation of the lm phonograph;

Figs. 18 and 19 represent sectional views of the remote control box at right angles to each other,`on lines I8-I8 and lil-I9 of Fig. 16; and Fig. 20 is an outside plan view of the remote control box.

Referring to Figs 1 and 2, there is a cabinet I0 of suitable construction and design, which in this instance has three compartments I2, I3 and I. The-top compartment I2 has a hinged lid I5 which affords easy access te the nlm-controlled phonograph mechanism mounted therein. For convenience have indicated this mechanism as a Whole by P, and the details thereof will be described in due course. The middle compartment I3 contains a radio receiver R of any approved type, and it will not be necessary to show linger piece I 'i operates a station dial I9, which is CAB tor shaft 34 between the two clutch rings 38 and 4 in the cabinet.

visible through an opening 20. The bottom compartment I4 contains a loudspeaker indicated as a whole by L, which I have shown for convenience in the form of a cone diaphragm operated by an electric driving unit 2| of any practical 1 construction. The front of compartment I4 is freely open to the outer air through an ornamental screen or perforated panel 22. The loudspeaker compartment I4 does not extend entirely across the cabinet and is flanked on both sides by a set of trays or drawers 23 suitable for storing lm reels 24.

The front panel 25 of the top compartment I2 has four rotary knobs or other finger pieces 26, 21, 28 and 29 projecting therefrom. The left knob 26 controls a switch for placing either the radio receiver or the film-controlled phonograph in operative condition, according to the position of pointer 26. The knob 21 is for the purpose of selecting any particular sound track on the record film for playing. The knob 28 controls the volume of reproduction. for either the phonograph or the radio receiver, and the knob 29 turns the electric current on and off for all apparatus Thev rear wall of cabinet i may be removable for easy access to the partsl inside. If desired, the transverse panels or base b'oards 30 and 3|, on which the phonograph mechanism and radio receiver are mounted, may be supported slidably between the side walls of the cabinet. This permits complete assembling of the receiver and .phonograph outside the cabinet.

I shall now describe in detail the construction of the film-controlled phonograph mechanism P.

mounted in the top compartment I2 of the cabinet, and for this purpose I shall refer mainly to Figs. 3-9. YThe base 30 supports a rectangular frame indicated as a whole by F on whichva U-shaped bracket 32 is rigidly mounted. The parts F and 32 may be a single casting (as of aluminum) or they can be shaped separately from straight bars of metal. A small electric motor 33 secured to base plate 30 has a driving shaft 34 which extends loosely through rotary sleeves 35 and 36 journalled in the sides of frame F, as shown in Fig. 5. One end of sleeve 35 carries a pinion 31, and the other end of the sleeve terminates in a toothed clutch ring 38. The

parts 35, 31 and 38 may be a singlecasting mounted lo'osely on shaft 34 between a pair of collars 39 and 40, which are fixed on the shaft to prevent axial movement of the parts. The other sleeve 36, which is also loosely mounted on shaft 34, carries a grooved pulley 4| at one `end and a toothed clutch ring 42 at the other end. A pair of spaced collars 43 and 44 xed on shaft 34 prevent axial movement of sleeve 36.

A slidable clutch sleeve 45 is keyed on the mo- 42. The opposite ends of clutch s1eeve45 terminate in fine teeth adapted to interlock with the adjacent teeth on clutch rings 38 and 42 when the sleeve is shifted in one direction or the other. The clutch sleeve 45 is operated by a bellcrank 46 pivoted on a pin or stud 41, which is carried by a bracket or plate 48 secured to the frame F by screws 49 or otherwise. The bellcrank 46 terminates in a yoke 50 which straddles the clutch sleeve 45, and this yoke carries a pair of rollers arranged to ride in the annular groove 52 of the clutch sleeve. A contracting coil spring 53 is attached at one end to bell-crank 46 and at the other end to frame F, whereby the spring normally holds the clutch sleeve 45 in engagement with clutch ring 42. This means that the grooved pulley 4I is normally connected to the motor shaft 84 and the'pinion 81 is normally disconnected from the shaft. The bellcrank 4l is rocked clockwise against the tension of spring I8 by a solenoid comprising a, coil 54 and a movable plunger 55, which is connected to one end of the bellcrank. A strap or collar 56 attached to frame F holds the coil 54 firmly in place. When the coil 54 is energized, it pulls 'up the magnetic plunger` 55 and thereby rocks the bellcrank 48 to shift the clutch sleeve 45 into locking engagement with clutch ring 38.

The base plate 30 carries a second bracket indicated as a whole by G, which comprises a post or standard 51 having three extensions 58, 59 and 60 (see Figs. 4 and 6) The parts 51-60 may be a single casting (as of aluminum) or they can be vstamped as a single plate from sheet metal.

A countershaft 6I is journalled at its endsin brackets 32 and 58 (see Fig. 5) and this shaft carries a grooved pulley 62, which is connected to the lower pulley 4| by a belt 63. 'Ihe pulley 62 is secured to shaft 6I in any practical way, as by cross-pin 64. It is clear from Fig. 5 that, when the bellcrank 46 is in normal position, the motor shaft 34 is connected to the countershaft 6|, which drives the lm sprockets of the phonograph mechanism. The lateral extension 32' of bracket 32 supports a bevel gear 65 by means of a rotary shaft 65' to which the gear is secured. The bevel gear 65 is permanently in mesh with a pair of bevel gears 66 and 61 on shaft 6I, which also carries a pair of gear wheels 68 and 69. The gear members 66 and 68 are secured to shaft 6| either as separate pieces or as a unitary casting. 'I'he gear members 61 and 69 are either connected together or cast in one piece, but they are loose on shaft 6|. The gear wheels 68 and 69 are of the same size and always rotate in opposite directions, as indicated by the arrows a and b in Fig. 5.

Referring to Fig. 5, the brackets 32 and 58 support a second shaft 10, which I will call the sprocket shaft, because it carries a sprocket wheel or cylinder 1I for feeding the sound film 12. 'Ihe cylinder 1| which is fixed on shaft 10, is provided with two rows of teeth 13 arranged to enter the sprocket holes 14 of the film and thereby feed the same in one direction or the other at predetermined uniform speed. The sprocket shaft 10 has keyed thereon a slidable sleeve 15 which carries at its ends a pair of pinions 16 and 11 of the same size. If desired, the parts 15, 16 and 11 may be cast or molded as a single piece. When the sleeve is shifted to the right (as viewed in Fig. 5), the pinion 16 is in mesh with gear wheel 68 to drive the sprocket 1I inthe direction of arrow c; and when the sleeve is shifted to the left, the pinion 11 engages gear wheel 69 to drive the sprocket in the direction of arrow d. We shall assume that, whenthe gear members 68 and 16 are connected, the sound film 12 is driven in a forward direction from left to right, as indicated by the arrow c in Fig. 3. When the gear members 69 and 11 are in mesh, the lm is fed in the reverse direction, as indicated bythe arrow d in Fig. 3. It is understood that only one pair of gears 68-16 and 69-11 can be in mesh at one time.

The clutch sleeve 15 is operated by an arm or lever 18 pivotally mounted on apin or-stud 19, which may conveniently be secured to bracket 48. The upperend of arm 18 is in the form of a yoke 18' which is provided with rollers arranged to enter the annular groove 88 in sleeve 15. Two

solenoid coils 8l and 82 are rigidly supported on top of frame F and held in place by straps 83 or otherwise. In the present construction, the bracket 32 is cut away at 32a (see Fig. 6) to make room for the rear coil 82. The two solenoid coils 8| and 82 operate a magnetic core or plunger 84, which is pivotally connected to arm 18 by a pin 85. When the coil 8| is energized,l the magnetic plunger 84 rocks the arm 18 to the right (as viewed in Fig. andrmoves the pinion 16 into engagement withgear wheel 68. VThe sprocket shaft 10 is now connected with the motor shaft 34 the sprocket shaft 10 for simultaneous operation to drive the film 12 forwardin the direction of arrow c .(Fig. 3). Whenthe-other coil 82 is energized, the plunger 84 rocks thefarm'18 to the `left andmoves the. pinion 1 1 intol engagement -with :gear 'wheel. 69,150 that the lm is fed v.inthe j ingmechanism-'at a predetermined uniform .rate

r reverse direction, as indicated by v thearrowitiin 3, lFor distinctionl shall referl tojthetwo'j'j solenoid coils 8| fandf82 Aasthe forward coil and' theA reverse coil, respectively. The magnetic plunger 84 and all parts connected therewith` are` held firmly in eitlieractuated position by a vleaf .spring 86, which-presses against a' pin"81 on. f clutch lever18. .-Thev-centralportion of spring "86 is so shaped v`that itpresses laterally 'against the pin 81 inthe direction in which the lever -18' was last actuated. The'retaining spring 86 may conveniently be attached to the coil straps83. Any other practical means may be used for holding the sleeve l in actuated position.

The sound film 1 2 is supported by a pair of reels or spools 88 and arrangedin alignment with the driving sprocket 1|. The film reels are mounted on rotary shafts 90 and 9|, which are journalled in brackets 92 and 93 secured to base plate 30. The reels 88 and 89 are so mounted on their respective shafts as to rotate therewith, and at least one of the reels is easily removable Afrom its shaft. .Inthe .present construction I have assumed that 88 is the original pay-out reel on which the filmv is wound when inserted into the machine. Consequently, this reel is removably mounted on shaft 90 in any practical way, as by providing thev outer end of the shaft with a pivoted latch 94. When this latch is swung into alignment with shaft 90, as indicated by the dotted outline 94 in Fig. 3, the film reel 88 may be inserted on or removed from the shaft. After the reel is in place, the latch 94 is swung into locking position against the sideof the reel. It is understood that the reel is automatically keyed to `the shaft bythe mere act of insertion. The other reel 89 may also beremovably mounted on shaft 9|, but that will usually not be necessary, because when the film is 'played through, it is wound back on reel 88, sothat only .the latter need be removed fo'r' the 'insertion of a new. reel. For this reason I'have shown the reel 89 mounted permanently on-.shaft 9| by means of a'collar 95.

in any practical way. The lateral extension or arm 59 of supporting frameG carries a rotary shaft 98 on which'two grooved pulleys 99 and |00 are mounted. IThese pulleys may be a single be cast or molded asa single piece. A belt |06 in one direction or other. 'I-he transmission connections are such that the reels 88 and v89 are rotated at the same speed tojmove, the sound fllm12facross the opticalfieldof the reproduc of feed in alternately :opposite directions. During the forward movement of the film, it is un- Avwound.r from `the initial; vpay-out reel- 88 and woundup onthe initial take-up reel 89. Dur- ,.ingthe -reversemovement of the film, it is un- Wound from-reel 89 and'wound back on reel 88,

" and vthis alternate reversing of the lm continues automatically until the last sound track is played through. This will be better understood from a later xportion of the specification. 'I'he point I want to bring outl here is the positive 'drive of both film reels 88 and 89 in either direction by means of the motor-driven sprocket shaft 10.

While the sprockets 1| land |03 feed the film through the optical field of the reproducing mechanism at a uniform velocity, it is evident that the rate of winding and unwinding of the end portions of the film will continuously vary. For example, looking at Fig. 4 and supposing the film to be moving from left to right, it is clear that the linear speed of unwinding from reel 88 keeps on decreasing, while the linear speed of winding up on the other reel 89 is increased. To

make allowance for these variations in the movements of the film on opposite sides of the feeding sprockets 1| and |03, I provide compensating' weights |09 and ||0 in the form of rollers which bear down on the film near the two reels and thereby form loops in the film on opposite sides of the sprockets. 'I'he `weighted rollers |09 and ||0 are carried by swinging arms H2, which are loosely pivoted on the reel shafts 90 and 9|. As the film. -winds off one reel onto the other, the weighted rollers v| 09 and ||0 automatically accommodate themselves to variations in the unwinding and winding-up speeds of the lm. The weighted rollers not only maintain the film taut between the sprockets 'IVI and' |03, but also assure the tight winding up of the im on either reel. It is perhaps advisable to cover the compensating rol1ers |09 and ||0 with soft material that -will no t injure the film, and these rollers are not-made heavier than'is necessay. If any undue pullis exerted on the film by the driv Ving sprockets 1| and |03 due to the varying rates of unwinding and winding up, the pulleys 96 'and 91 wiil slip in their belts. .and prevent tearing of the film.

The film 12 has a plurality of sound tracks running in alternately opposite directions. These tracks are diagrammatically indicated in Fig. 13,

and byway of .example I have shown six tracks,I

but anyother number maybeused, depending upon the avaliable width or the fum and the width of each track. A-'The three tracks numbered 1, 3 land 5j-are played'during the forward movement ofthe film (that is, from vleft to right',

as viewed in Figs. 3 and 13), while the evennumbered tracks 2, 4, and 6 are played when the film runs in the reverse direction. When the end of a track is reached, the direction of rotation of sprocket shaft 10 is automatically reversed by the-shifting of clutch sleeve 15, and vat the same tim'ethe next sound track is brought into operative position. This goes on until the end Vof the last track is reached, whereupon the machine automatically stops. Only one sound track'is played at a time and any selected track may be brought into playing position when the machine is started. Suppose we have a film on which three different pieces are recorded, as indicated in Fig. 15. The title of each piece and the number of the track in which it begins are marked on the side of reel 88. Perhaps the simplest way of doing this is to paste on one side of the reel a label having the required information printed thereon. If a person wants to play Gounods Ave Maria, he turns the knob 21 at the front of the cabinet to number 5 on the associated index, and that starts the machine playingv track No. 5 on the nlm without going through the four preceding tracks. It is preferable to start each recording` on 'an odd# -numberedtrack, because these tracks are played bracket orshelf IIS, and'a plate `I I4, which 'are conductingst'rip |2|- is`connected to the base of socket |20 andextendsoutof the box for contact with ascrewfor--bindingpost |22 carried by thev attached inany practical `wayand'a box ||5 is `slidably supported between those `two members.

For this purposethel sides ofY the box are formed nearthe top with grooves IIE adapted to receive tenons ||1 onjplateii I4, `and the bottom of the box isfrecessed at ||8 to fit snugly over` the top of shelf ||3. This construction is lbestshown in Fig. 8; The box 1 I5 .contains -an electric" lamp ||9 screwed *into-"ajmetal socket |20, which suitably fastened, ltothe bottomof the boxLfA shelf ||3 '(seeFig'. 7);" This arrangement makes it easy to 'connect one terminal of lamp y| I9 in 1 circuit. The supporting .shelf li3vhas'ametal.

socket |23 adapted "to receive a screw |24 which extends into firm pressure contact with the central terminal Aof lamp IISI. The-screwthreaded `socket |23, which is permanently secured in shelf |3, is intended to receive one end of a conductor for .connecting the central lterminal ofthe lamp in circuit. To remove the lamp box 5,7it is only necessary to loosen Athe screw I24 until1the ex-v tension |24" thereof-iswithdrawn from the bottom i! hole of the box, whereupon thellatter is free to be slid out. 'Before removing the box it is advisable to loosen `the contact screw |22. The easyre.-` moval of' box ||5 makes4 ita simple mattertol replace a burnt out or defectiveylampwith a new one.l When. thelv screw| 24 .is in contact with the bottom offthe lampsocket, the box 'I I5 is locked in place.j Thelamp |l|9s surrounded bya suit,-` ably shaped reilector V|25',which may consist of i polished sheet `metal and form an integral extension of lamp socket |20: 1 The parts |2|I-and.

|25 may be shaped as a unit from-sheet brass and the inside of the. reflector bowl |25 is plated with nickel, silver, or other mirror-like surface.

The shelf or plate III, rWhich formsthetopl of lamp box I5; is cut away or scooped out on both v sides. to form a pair of opposing cylindrical'recenter to form a long narrow slit |23 for the 3 and 6) for accessto the interior of the box. A

suitable spring latch |34 holds the door |23' tightly closed. A second guide plate |35 is secured to post 51 by'brackets |35' or otherwise, and'it is suiiciently spaced from the upper guide i* `plate |32 to receive the phonograph film 12 in a snug fit.

The opposing inner surfaces of guide plates |32 and |35 are preferably lined or otherwise covered with soft material to prevent wear on the moving film. The ends of the guide plates are preferably rounded or diverging (see Fig. 8) to eliminate sharp contact cornersfand at the same time facilitate the insertion of the film.

The stationary.; guidegplate'sv ,|32 and v|25 are provided with. aligned, transverse slits |35, 'which are spaced exactlytheA same as the sound tracks on the lm. In the present instance, the illm tric cell |31 ofV a type particularlyadapted for' sound reproduction. Cells of this kind are obtainable inthe market and their construction is so well understoodv that I need not go into detailed is of such dimensions that light reaches the explanationherev Thefwindowf|38,ofcell |31@v photo-electric element through .any-pair of aligned 'f slits |36.` The reflector' |.25'oflampf'l I9 creates an optical field wide enough to pass vthrough all the lslits I 36- withl substantially .equal -intensity.

guide plates |32 and |35 be' exposed tolarnpl I3,"

and for this purpose'I interposearotary cylin' drical shutter |33 between' the 'slotted plate I4l Theslit |20 in shelff|-|4 is inalignment with-.the

track slits |36 and of sulllcient length,` to expose plate v| I4, and the guiderplat'e. |35 may beformed on the bottom with a simil'ari'ec'essV |40 to receive",V the-cylinder. The rotary shutterv|33- is vprovided with diametricy holeslifarrangedsin di'erent` Fig.,A 8 shows ,I radial planes and spacedfrom eachother by equalv magies, as shown in'y Figs,l ,fi-,4.7i and-il., Si-'ncel the l lm 12 has been r'described asi carry'ir'igy sixfsound c, tracks, there are Isix diametric apertures I'llin y the cylindricalshutter |39. The axial spacing ofi.; .v apertures |41 is such thateach aperturevcontrols l one pair of aligned track .slits |35. how thel shutter apertures/|41 allow light rays metal like aluminum)` crit-may` be 'molded of' suitable composition material like bakelite. f The holes |4| 'can be' formed durlngutlie castingA or u cesses |25 and |2-1. These recesses meet atthe molding operation, but they mayalso be bored 15 separately after the cylinder has beenmade. The

outer surface of cylinder |39 may be covered (except for the holes |4| with black velvet or similar material adapted to form a light-proof 5 contact with plates ||4 and |35. It is evident that instead of making the cylinder |39 solid, it can be formed as a hollow shell.

The cylindrical shutter |39 is xed on the inner end of a rotary shaft |42, which is supported in the front panel 25 and the post 51. The finger piece 21 attached to the outer end of shaft |42 carries or otherwise operates a pointer |43 (Fig. 2a) 'to indicate the number of the track which the machine is playing at any time. In the present instance, the index |44 associated with the pointer .|43 applies to a fiim having six tracks running in alternately opposite directions, as

illustrated in Fig. 13. Referring again to Fig. '1,

two clutch members |45 and |46 are mounted on shaft |42 in such a way that the first member is loose on the shaft while the other one is keyed to the shaft for rotation therewith. These clutch members are provided with interlocking teeth |41, which are so shaped that clockwise movement of clutch member |45 (as indicated by arrow |48) carries the clutch member |46 along with it to rotate the shaft |42 and shutter |39. When the clutch member |45 is turned the other way, its teeth ride over the teeth of clutch member |46 without actuating the latter.

An axially expanding coil spring |49 on shaft |42 presses against the clutch member |45 and normally holds the latter in locking engagement with clutch member |46, while at the same time permitting the necessary sliding movement of clutch member |45 on the shaft. The front end of spring |46 bears against a fixed collar |50 on shaft |42. The loose clutch member |45 is provided with an extension |5| which is connected to the magnetic core |52 of the solenoid coil |53. The magnetic core |52 carries a cross-pin `|54 which passes through a slot in extension |5| (see Fig. 9). The solenoid coil |53 is seated in a block or cradle |55, which is mounted on a horizontal shelf |56 secured to the front panel 25 and post 51. A strap |51 holds the coil |53 firmly in position. A contracting coil spring |58 attached to the movable core |52 or extension |5| normally holds the latter against a fixed stop |59, as best shown, in Fig. 9. One end of spring |58 is attached to a fixed pin or stud |60. When the solenoid coil |53 is energized, it pulls the magnetic core |52 inwardly until the extension |5| of clutch member |45 strikes a second fixed stop |6|. When the coil is deenergized, the tensioned spring |58 automatically pulls the clutch member |45` in the reverse direction until the extension |5| encounters the fixed stop |59. The three pins or studs |59, mounted on the horizontal shelf |56.

The post 5l' carries an insulating ring |62, which is secured by screws |63 or otherwise in concentric relation to shutter shaft |42. The ring |62 carries a series of evenly spaced contacts 64, of which there are twelve in the present instance, because we are assuming that the film 12 has six record tracks. The twelve contacts |64 are divided into two sets of six each, and the contacts of the first set are distinguished by the suffix letters a-f, while the contacts of the second set are identified by the suiiix marks a-f. The contacts |64 are preferably small plates -of sheet metal (like brass) embedded in the insulated ring |62, and each plate is formed with a v |60 and |6| may conveniently be molded of insulating material (like bakelite, hard rubber, ber, and the like), the recessedplates |64 may be embedded in the ring during the molding operation. For convenience I have referred to the parts |64 as contacts, but only two of them are connected in circuit, and those two are the diametrically opposite contacts |64f and |64f. The reason for this will presently become clear.

The recessed plates |64 are adapted to be engaged by an insulated contact arm |66 mounted on the shutter shaft |42. In the present construction, the contact armv |66 is an integral extension of a conducting plate |61 (see Fig. 7) attached to an insulating disk |60, which is keyed or otherwise fastened to shaft |42. The rotary arm .|66 is formed with a rearwardly projecting portion |69 adapted to fit snugly into the correspondingly shaped recess |65 of contacts |64. By making the arm |66 of spring metal, the projection |69 will automatically snap into the recess |65 of each contact |64 when lthe arm is moved from one position to the next. This releasable locking engagement between the spring arm |66 and the associated contacts |64 holds the shutter |39 firmly in any adjusted position. It is evident that all the metal plates |64 except the two numbered |64f and i64f may be omitted if the insulated ring |62 is provided with the recesses |65 for receiving the projection |69 of spring arm |66. The insulatedring |62 carries a spring contact |10, which always presses against plate |61 without interfering with the rotary movements thereof. The spring arm |10 preferably projects through the ring |62 for easy attachment of a circuit conductor.

The circumferential spacing of the centering contacts |64isidentical with that of the diametric .apertures |4| in the cylindrical shutter |39.

Comparing Figs. '1 and 9, it will be seen that when the switch arm |66 engages contact |64a, the shutter is in position to expose the rst sound track to the light field of lamp H6. In Fig. 7, the film 12 is inserted in such a way that track No. l is at the right and track No. 6 at the left, with the other tracks in-between. When the switch arm |66 engages the next contact |6427, the next opening i4! comes into operative alignment with sound track No. 2, and so on for each successive movement of the switch arm until the last'track is reached, which happens when the switch arm engages the circuit contact |64f. After that, the arm |66 and shutter |39 are again in position for track No. 1 of the next film. That is to say, when the switch arm |66 engages cont-act |64a (which is diametrically opposite the corresponding contact |64a) the cylindrical shutter |39 is back to the starting position shown4 in Fig. '1, even though it has completed only a half revolution. This is explained by the fact that each diametric light passage |4| in the shutter requires two holes in the surface of the cylinder, and the annular spacing of those twelve holes is identical with the spacing of the twelve contacts |64 on the insulated ring |02.

When the point |43 of the track-selector knob 21 points to No. l at the top of index |44 (see Fig. 2a) the shutter |39 and switch arm 66v are in the position Shown in Figs. 7 and 9, so that track No. 1 of the film is in playing position. When the pointer |43 is turned to No. 1 at the bottom of index |44, the switch arm |66 engages contact |64a', but the shutter |39 will again exposel sound track No. 1 of the film. When the knob 21 is turned clockwise to No. 3 on the associated index, the switch arm |68 engages contact |64c (or |84c') and the shutter |39 is in position to expose track No. 3 to the optical field. Similarly,

numbered tracks 2, 4 and 6 of the film are not represented in the index |44 of selector knob 21, is

because those tracks are played during the reverse movement of the film and are supposed to be a continuation of the records that begin on the odd-numbered tracks. For example, referring to Fig. 15, it is assumed that the Blue Danube Waltz occupies tracks Nos. 3 and 4, and Gounods Ave Maria takes in the remaining two tracks.

The track selector knob 21 can be turned only right-handed or clockwise, and is locked against rotation the other way. When the knob 21 is turned clockwise, the clutch member |45 (which is loose on shaft |42) remains stationary and the teeth of clutch member |46 ride over the inclined portions of the teeth on clutch member |45. This will be clear by looking at Fig. 7. It should be noted that the clutch member |45 is slidably mounted on shaft |42, so that the rotary movements of clutch member |46 (which is fixed on the shaft) push the other clutch member out of the way against the tension of spring |49. This spring is sufficiently weak to permit axial movevment of clutch member |45 on shaft |42 while the tensioned spring |58 holds the clutch member against rotary movement. In other words, during the manual operation of shutter |39, thev clutch member |45 remains inoperative, except that it prevents rotation of shaft |42 in a counterclockwise direction. That is so, because the two clutch V|42 along until the extension |5| strikes the fixed stop'l6l. The switch arm |66 is now in engagement with the next contact |64, and the shutter |39 exposes the next soundtrack to the optical field. W'hen the coil |53 is de-energized, the spring |58 pulls the clutch member |45 back to initial position until the extension |5| strikes the stop |59. However, the shaft |42 and shutter |39 remain in previously actuated position. During the counterclockwise movement of clutch member 45, the coil spring |49 permits the clutch member to slide over the teeth of the stationary clutch member |46. 'I'he frictional engagement of the spring arm |66 with any one of the contacts |64 is sufficient to hold the shaft |42 in adjusted position during the return movement of clutch member |45.

In the broader aspect of my invention, the contacts |64 and shutter openings |4| may be so arranged that a complete revolution of shaft |42 is required to cover all the sound tracks in the film, especially if the latter has -morev than six tracks. 'Ihe cylindrical shutter |39 may also be replaced by a shutter in the form of a flat rotary disk fixed on shaft 42, and the light holes in that disk would be spaced radially to correspond to the position of contacts |64 on ring |62. By making the shutter |39 cylindrical and mounting it in horizontal position, the track-selector knob 21 can be mounted on the front panel of the cabinet for direct connection with shaft |42. At the same time, the reels 88 and 89 can be so arranged that the film 12 runs through the machine horizontally, so that it is easy and convenient to thread the film through the optical mechanism. If desired, however, the parts may be so arranged that the film runs through the machine in a vertical plane, and the compartment I2 may be opened at the front instead of the top. A film one thousand feet long and provided with six or eight record tracks is capable of holding an entire symphony, or an opera, or even a book, and will play for hours without attention. The reel for such a film will have marked thereon the numbers of the tracks where the different parts of the symphony or the different acts of the opera begin, so that a person can select any particular portion of the film for reproduction. by simply adjusting the selector knob 21. v f

Referring to Fig. 5, the front end of motor shaft y34 carries a pinion |1I, which is in mesh vwith a large gear wheel |12 xed on a countershaft |13. It is convenient to support the shaft |13 between the front panel 25 and the bracket arm 60. The rotary shaft |13 also carries a pinion |14 adapted to mesh with a large gear wheel |15, which is slidably keyed on a rotary shaft |16. The latter may be mounted between the front panel 25 and the bracket plate 58. A sleeve |11 attached to (or formed integral with) the gear vwheel |15 has an annular groove |18 for receiving the ends of a yoke |19 which forms part of a bellcrank |80 pivoted on a pin or stud |8|. This pivot pin is mounted in a bracket |82 attached to the supporting plate 58 by bolts |83 or otherwise. The bellcrank |80 carries a crosspin |84 to which a solenoid core |85 is connected. A coil |86 is attached to bracket plate 58 by straps |81 or otherwise, and the core |85 normally projects upward into the coil. A contracting coil spring |88 is connected at one end to cross-pin |84, vand at the other end to a fixed lug or pin |89 projecting from plate 58. The normal action of spring |88 is to hold the gear wheel |15 out of mesh with pinion |14.4 A- collar |90 xed on shaft |16 acts as a stop for the axial movement of gear wheel |15 under the action of spring |88.

When the solenoid coil |86 is energized, the magnetic plunger |85 is pulled up and rocks the bellcrank |80 clockwise to slide the gear wheel |15 into mesh with pinion |14. Suitable stop means, such as a collar |9| on shaft |16, limits the sliding movement of gear wheel |15 to the left (as viewed in Fig. 5). As long as coil |86 remains energized, the shaft |16 is operated by the motor shaft 34 at greatly reduced speed. When the circuit of coil |86 is broken, the tensioned coil spring |88 instantly shifts the gear wheel |15 out of mesh with pinion |14, and the shaft |16 stops. The purpose of shaft |16 is to control the volume of loudspeaker L by moving an insulated contact arm |92 over a resistance element |93, which may conveniently be attached to the front panel 25 of the cabinet. The contact arm |92 is secured to shaft |16 so as to rotate therewith and is preferably in the form of a spring finger of vgood conducting metal adapted to press firmly against the resistance element |93. The volume-controlling knob 29 which projects from panel 25 of the cabinet is connected gearing to reggulate the loudspeaker volume as required. The purpose of operating the volumecontrolling shaft |16 from the motor shaft 34 is to permit regulation of the loudspeaker from a remote point, as will be fully explained later on. Since the gear wheel |15 is normally disconnected from the motor shaft 34, the rheostat arm |92 is free to be turned by hand without pret liminary adjustment of any part of the machine.

I have previously mentioned that the rear end of the motor shaft 34 caries a pinion 31, which is normally loose on the shaft, as shown in Fig. 5. The pinion 31 is permanently in mesh with a gear wheel |94 fixed on a rotary stub-shaft |95, which is supported between the frame F and a bracket-|96 on base 30. A pulley |91 xed on shaft |95 is connected by a belt |98 to a pulley |99 in the radio compartment |3 (see Fig. 1).. The lower pulley |99 is mounted on a shaft 200 which is joumalled in a bracket 20| carried by the transverse partition 3|. It is understood that the belt-connected pulleys |91 and |99 represent any suitable transmission drive between shafts |95 and 200. The transverse partition 30 is provided with openings for the passage of belt or chain |98. The motordriven shaft 200 is connected to the tuning shaft |6 through an automatic reversing mechanism indicated diagrammatically by the rectangular outline 202. It will not be necessary to show or describe the details of reversing mechanism 202, because any practical means can be used for automatically reversing the rotation of the tuning shaft |6-at each end of the dial. The reversing mechanism 202 is such that it permits manual operation of the tuning shaft I6 by means of knob |1 at the front of the cabinet. The purpose of operating the tuning shaft from the electric motor 33 when coil 54 is energized (see Fig. 5) is to permit tuning of the receiver from a remote control box, which I shall presently describe. If no remote controlv A`tobase plate 30 in any practical way, has an upright extension 206 which carries two insulated brackets 201 and208 secured by screws 208 or otherwise. The' bracket 201 carries threeinsulated contacts 209, 2|0. and2||, and the other bracket 208 has `an insulated contact 2|2. In practice, the parts 203, 206, 201 and-208 can be molded as, a single piece of bakelite, hard rubber, fiber, or other insulating composition, so that no separate insulation is `needed for the4 contacts. A rock shaft 2 I3 journalled in the front panel 25 and the upright extension 206 ofblockl contacts 2|6, 2|1 and 2|8 are in firmA engagement with the insulated stationary contacts 209, 2|0 and 2H, respectively. When the arm 2|4 vis rocked to the left, the contact 2|9 engages the stationary contact 2|2. The two side arms 2|5 When the arm 2|4 is in the position shown in Fig. 4theconstitute a centrally pivoted lever which carries at its ends a pair of solenoid plungers 220, and 22| arranged in operative relation to the stationary coils 204 and 205, respectively. When the solenoid coil 204 is energized, the cross-piece K is rocked clockwise (as viewed in Fig. 4), and the three switches 209-2I6, 2|0-2|1.and 2| 2|8 are closed. When the other solenoid coil 205 is energized, the cross-piece is rocked the other way to close the switch contacts 2|2--2|9.

The lower extension 2|5' of the cross-piece is pointed to enter a pair of grooves or notches 222 and 223 formed in a movable disk 224. The supporting block 203 is provided with a chamber 225 other way by the energizing of coil 205, the pointed end of extension 2|5' enters the recess 223 in disk 224, so that the contact 2|9 is held against the stationary contact 2|2. Any other practical means may be employed to hold the insulatedv switch arm 2|4 in either actuated position'. The knob 26 on the front panel 250i the cabinet is attached to the outer end of shaft 2|3 for manually operating the switch arm 2 I4 independently of the solenoids 204 and 205. When the pointer 26' of knob 26 indicates the word Film (see Fig. 2), ther switch arm 2|4 is in the position shown in Fig. 4 to place the film phonograph circuits lin operative condition. When the pointer 26' is moved toward the word Radio, the switch arm 2 |4 is rocked the other way to close the contacts 2| 2 and 2|9. The purpose of the solenoid coils 204 and 205 is to control the operation of switch arm 2|4 from a distance, as will be better understood when I describe the circuit diagram of Fig. 14. If no lremotecontrol of switch arm 2|4 is desired, the associated solenoid mechanism is omitted..

'Ihe switch knob 29 projecting from the front panel 25 of the cabinet ,is connected to a rot-ary shaft221 which carries a cam 228 arranged to operate a switch'arm 229 (see Figs. 3 and 4). This arm may simply be a spring blade mounted at one end on aninsulating block 230,which may conveniently be attached to the front panel 25. The normal set or tension of switch arm 229 is such that it is out of engagement with an insulated stationary contact 23|, which may also be vmounted'on panel 25. The cam 228 carries a pin 232 arranged to engagea pair'of fixed stops 233 and 234 for limiting the movement of knob 29 to the correct on and .off positions. When the pin 232 engages the stop 233', the switch armI 229-is in open position, as shown in Fig. 4:. Whenv the knob 29 is turned to the right until the pin 232 strikes the otherstop 234, the point of cam 228 `engages the hump 229 of switch' arm 229 and forces lthe latter into pressure engagement with the stationary contact 23|. This will beclearl by looking at Fig. 13. The cooperating cam. elements 228 and 229 are so shaped that the knob 29 remains safely in either position. When the end of the last track is reached, the switchvarm `70 The insulated rollers 241 and 241' tached to the front panel by a strap 238 or otherwise. When the solenoid coil 235 is energized, the plunger 236 is pulled down until the pin 232 strikes the off stop 233, whereby the switch arm 229 is moved to open position. This operation takes place only when the cam 228 is in switch-closing position, for the automatic energizing of coil 235 is to open all circuits when the machine is through playing. In the broad aspect 10 of 'my invention any suitable on-off switch may be operated by shaft 221. v

Referring to Fig. 13, itxwill be. seen that ,the

Cil

sound film 12 .is provided at its two edges with a .pair of notches'239 `and 240, which arespaced l5 at-a certain distancefroni the two ends of the soundtracks. `The guide plates l,|32 and |35 a're lprovided at theopposite edgesy with notches 2|l| and 242, which are shaped likethe notches in the film. For convenience` I shall refer to notches 24| 2c and was theguifdenotches. The dotted line, -243 in Fig.- 13 represents diagrammatically the .y

7 position of `vthel optical "field through Which-thefilm moves. When'the ends of soundtracks Nos.

`1, 3, and 5 are reached Ain the.pmyingof the-111m, f 4 25 the. notch 239 registers with thestat'ionary guide notch 24| During the' reverse running'of vfilm, 12 from vright to left `(as :viewed in-Fig. 13),'.the

f notch 240 registers with guide notch 242 when the" ends of the even-numbered sound tracks 2, 4 and vFlg."5.'Since the twosw'itchdevices controlled 3,5.;by'jrthenotches are; substantiallyidentical, a de-` tailed description'ofonewill suffice for both, and II shall use `the same reference numerals, except that in-designating certain parts of one device I shall-.use reference numerals with prime marks 40 to.` preventconfusion.

Referring to Figs.` 11 andy 12, the switch controlled by film notch 239 is mounted as a unit on -anfinsulating' plate or block 244, While theswitch 'controlled by film notch 240 is mounted'on an "f 45, insulated bracket 245. The vplate zu may-be atv'.tached'to bracket arm 59 or-itfmay bea lateral 1.45 f is @secured to' the' topof the. rectangular sup- `fportingframeF, asshown in Fig.`6.v` Afslidable plate-,2,46 carries at onev end. a roller 241y (241') j whichjisl normally. pressed against the edge of the :lmf by' aV contracting coil spring .248 connected to thectherend of the slidable' plate. The-rollers lll-.-241f-"241 are.preferablygmadezofnonfmetallic' f material thatwill'not injure or abrade the film,

vandthe springs 248 hold the rollers against the ;'ffilm4 with .light pressure. Thepslidable plate 246 V n ofeach switch device carries a contact 249 (249') u arranged to engagea stationary contactv 250 (250'). If the'slidableplates 246 are made' of goodconducting metal, the contacts 249-249' I may be integral lugs struck up from the body of the plates. If the latter are of insulating materialV (for example, bakelite) the contacts 249 and 249' may be small pins or blocks of brass yscrewed or riveted to the plates. The stationary contacts 250 and 250 may be spring fingers attached to the top of their respective supports 244 and 245.

are arranged in line with the stationary guide notches 24| and 242, respectively, as shown in Figs. 3

and 13. During the operation of film 12 in either direction, the rollers 241 and 241 are held out l uref-,the associated guide notches 24| and 242 by connected thereto. 'nected to conductor 255 in series with coil 235. A74As I shall eicplain later, the coil 251 is mounted 35 extension offring |62 (see Fig. 4). Thebracket y the edge of the film, so that the switches 249--250 and 249-250 are open. When the end of an odd-numbered sound track 1, 3 and 5 is reached,

the film notch 239 registers with guide notch 24|,

l 2, 4 and 6 is reached, the film notch 240 registers with guide notch 242 and the roller 241' is forced bythe connected spring 248 into the guide notch,

Awhereby, the movable contact 249 engages the i fixed contact'250..

This energizes the solenoid 15 coil 6| to reversev'the movement of the film, except that 'the machine stops at the e'nd of the last track.

, Stillvreferring to Fig;` 13, thereis aplug '25| adapted .tobe inserted in an ordinary y'house-'2,0

lighting socket, `and this plug is connected to twocircuit leads 252 and 253. One of vthese con-I ductors (in this instance, the lead 253) lincludes the main Apower s witch 229-23|. Since the elecltric motor 33 and the various'solenoid coils pre- 25 viously mentioned are adapted to operate at low voltage, the main conductors 252-253 are connected to asuitable voltage reducer 254, which need not be described in detail, as it formswno 'part' of Athis invention. It is enough to say that 30 the wiresy 255 and 256 supply current at the required'low voltage to the various electric devices A solenoid coil 251 is conin a remote control box for automatically opening all circuits when the sound film is played through. A wire 258 connects one end of coil 235 with the two contacts |64f and |64f, which are connected by a wire 259. In actual practice, the connection 40 259 may be a strip of brass embedded in the insulated ring |62.

The driving motor 33 is connected across the low voltage leads 255- 256 and is therefore energized whenever the switch arm 229 is closed, 45

provided the knob 26 is in film position. For convenience I have indicated in Fig. 13 a direct ycurrent motor which is supposed to run always in other end of coil 8| is connectedby awirel 262 to the stationary switch contact 250. andthe associated movable contact 249."is'connected by.

a wire 263 to the low voltagezmain'255n; rOne side of coil 82 is connected by a wirep264" to the 60 stationary contact 250, and a wire 265 connects the other side of the coil to conductor 255. If the house-lighting system operates on alternating current, a suitable rectifier 266 maybe interposed.

'I'he operation of thefilrn-controlled phonograph mechanism P will be understood from the preceding description, but I may summarize it for convenience as follows:` Assuming that the machine has been loaded with a sound film which is to be played from track` No. 1 throughthe last track, the operator first sees that the knob 26 is in film position and that the track-selector knob 21 points to 'track No. 1. vThe knob 29 is now turned to on position for closing the switch aossnsi Y am 229. The driving motor 33 is energized and operates the film 12 at correct speed across the optical neld. The direction of movement of the nlm is forward, or from left to right in Fig. 13. 'I'he variations in the degree of transparency in the sound track cause the light from lamp I|9 to reach the photo-electric element of cell |31 with corresponding intensities which produce current impulses that operate or control the loudspeaker L. The circuit connections between the photocell |31 and* the loudspeaker will be'explained in the description of Fig. 14, and I need not go into them at this point.

When the end of the first sound track is reached, the film notch 239 registers with the stationary guide notch 24| and switch 249-250 is automatically closed in the manner previously described. Coils 82 and. |53 are now energized through the following circuit: Beginning 'with the low voltage lead 255, wire 265, coil 82, wire 264, across the closed contacts 250 and 249, wire 260, and through coil 53 to the return conductor 256. The energized solenoid coil 82 rocks the plvoted lever 13 to the left (as viewed in Figs. 5 and 13) and shifts the pinion 11 into mesh with gear wheel 69, whereby the sprocket shaft 10 is rotated in the reverse direction to drive the lm from right to left. When the coil |53 is energized, the cylindrical shutter |39 is turned to bring the next opening I4| into line with sound 'track No. 2. The adjustment of shutter |39 takes place simultaneously with the stopping and reversing of the lm, so that track No. 2 is exposed to the optical field of the reproducing mechanism almost immediately after the end of the iirst track is reached. In other words, the jump from the flrst to the second track is instantaneous and scarcely noticeable. If track No. 2 is a continuation of the recording .on track No. 1, the jump from one track to the other may occur during a pause in the recording, whether the latter be speech or music, and this applies to all the other tracks on the film.

When the lm reverses to play track No. 2, the notch 236 forces theroller 291 back again to initial position and the switch 249-256 is opened to cut the coils 82 and |53 out of circuit, thereby preventing a waste of current. When the end oi sound track No. 2 is reached, the lm notch 240 registers with the stationary guide notch 242 and allows the roller 241 to move inwardly, thereby carrying the switch arm 249' against the stationary contact 256'. This closes the circuit of coils 6| and |53 as follows: from conductors 255 and 263 across the closed switch249'-256', wire 262, coil 8|, wire 26|, and through coil |53 to the return conductor 256. The energized solenoid 8| rocks the pivoted lever 18 clockwise,

and moves the pinion 16 into mesh with gear wheel 69, whereby the sprocket shaft 'i6 is again connected for forward movement of the film.

. The second energizing of coil |53 moves the rotary shutter |39 until the next opening |4| is in line with sound track No. 3. The contact arm |66 movable with the shutter is now in engagement with centering piece |660, which holds'the shut ter opening in correct position against accidental displacement.

The automatic reversal of the film-driving shaft 1E! and the accompanying adjustment of the cylindrical shutter |39 take place at the end of each record track. When the shutter |39 is moved at the end of track No. 5 into position for the last track No. 6, the switch arm |66 engages contact |66f (or iEf') and remains in that position during the playing' of the last track. No circuits are closed by tle mere engagement of arm |66 with contact |64! or |64f' as long as the nlm-controlled switches 249-250 and 259'-250 are open. .When the-end of the last track No. 6

Vis reachedand the illm notch 250 registers with the guide notch 242, the consequent closing of switch 249-250 energizes the two'solenoid coils 235 and 251 through the following connections: Conductor 255, through coils 251 and 235` in series, wire 258, contact |6lf (or |64f') switch arm |66, and return conductor 256. -The energizing of coil 235 rocks-the cam 228 to open the movable switch arm 229, so that the electric power supply is cut off for all circuits in the cabinet and the machine automatically stops. The energizing of coil25'| also opens a main switch in the remote control box, as I shall fully explain when I come to 'describe Figs. 16-20. The notches 239 and 240 in the iilm are elongated to take care of any continued movement of the film due to the momentum of the driving connections prior to the moment of actual reversal.

In Fig. 14 I have shown diagrammatically only so much of a radio receiver system as is nece sary to an understanding of my invention. As previously mentioned, the radio receiver R in cabinet I0 may be of any approved type, and since electrical experts are familiar with standard receiver circuits, I deem it sumcient to show an input coil 261 and an output coil 266 connected through amplifying stages AI, A2 and A3. The output coil 268 is in the plate circuit of the last amplifying stage and constitutes the primary of a transformer which has a secondary coil 269 in the circuit of loudspeaker L. The volume-controlling rheostat |93 is shunted across the loudspeaker coil 269. The resistance element |93 is constructed in the form of a. circle having a gap between points |93a' and |93b.

When the rheostat arm |92 is in the position shown in Fig. 14, the rheostat circuit is open and the loudspeaker operates at maximum volume. As the 'arm |92 slowly rotates clockwise, the resistance in the rheostat shunt circuit is graduaiiy cut down and the loudspeaker volume is correspondingly decreased.

When the controlling arm |92 reaches the position indicated at |92', the loudspeaker unit 2i is practically short-circuited and the diaphragm does not vibrate, or at least it vibrates with minimum volume. tate clockwise from position |92', the resistance in the rheostat shunt circuit is gradually increased, so that more current flows through the secondary coil 269, and the loudspeaker volume increases accordingly, until it reaches its maximum when the rheostat arm is momentarily out of contact with both ends w3c-|636 of resistance element |93. It is thus clear that for each revolution of the rotary contact arm |92, the loudspeaker volume changes from maximum to minimum and from minimum back to maximum. Since the arm |92 rotates veryslowly, a `person can easily determine the degree of volurne he Wants and stop the controlling arm in the right position.A As previously explained, the rheostat arm |92 is manually operable from the cabinet by means of knob 26, and it may also be actuated from the remote control box by energizing the solenoid coil |86, which connects the shaft |76 to the motor shaft |36.

Before continuing with the description of Fig. 14, I wish to make it clear that Figs. 13 and 14 supplement each other, but it was impossible to As the arm |92 continues to ro- Y combine them on a single sheet. Corresponding parts and circuit wiring in the two diagrams are indicated by like reference characters. The photo cell 131 has a'. light-sensitive cathode 218 connected by a wire 21| to the stationary switch contact 218. The anode 212 of cell 131 is connected by a wire 213 to one side of the plate circuit of vacuum tube 214 in amplifying stage A1. The plate coil 215 is connected at one side to the positive terminal of the usual plate battery 218, and'the negative terminal of the battery is connected by a wire 211 to the insulated contact 218 on the pivoted switch arm 214. One side of the lament 218 in tube 214 is connected by a wire 218 to the stationary switch contact 212, and the other side of the lament is connected to one terminal of the usual lament battery 288. The other terminal of this battery is connected by a wire 281 to the insulated contact 211 mounted on switch arm 214. The wires 211 and 28| are electrically connected at point 282. The filament of the electric lamp |18 is connected at one side by a wire 283 to the stationary switch contact 2| and the other side of the nlament is connected by a wire 284 to the main conductor 253. The insulated switch contact 218 on pivot arm 214 is connected by a wire 285 to the other circuit main 252.

When the switch arm 214 is in iilm" position, the circuit of lamp 118 is closed through contacts 218-211, wires 283, through the filament of lamp 118, wire 284, and return conductor 253. This assumes, of course, that the main switch 228-231 or 352-356 is closed. At the same time the circuit of plate battery 218 is completed through coil 215, wire 213, across the electronic space 286 of cell |31 to cathode 218, wire 21|, closedv switch 218-211, and through wire 28| to the negative side of the battery. It should be noted that the filament circuit of vacuum tube 214 is open, so that the tube is inoperative and the radio set is therefore disconnected as long as the phonograph is in playing condition. The circuit of the film-driving motor 33 is closed through wires 255 and 342, windings of the ,motor, wire 385, closed switch contacts 288-218, wire 384, and return conductor 258. When the switch arm 214 is moved to radio position, the switches 288-218, 218-211 and 2| 1-218 are opened and the switch 212-218 is closed, whereby the filament circuit of tube 214 is completed to make the tube operative for the radio receiver system. In other words, when the knob 28 on cabinet 18 is turned to radio", the nlm phonograph mechanism is cut out of operation and the radio reeciver functions in the usual way. When the knob 25 is turned to film, the radio receiver is disconnected from the radio frequency input and the reproducer mechanism of the phonograph utilizes the amplifying circuits of the radio receiver to operate the loudspeaker L. 'I'he cabinet may contain only the phonograph mechanism and no radio receiver, but' since the same amplifying system can be used for both pieces of'apparatus, it is desirable to embody both in the same cabinet.

I shall now describe my new remote control box 'for fully controlling the film phonograph and radio receiver from a distance. Referring to Figs. 16-28, there is a small rectangular box indicated as a whole by 281, which may be of sheet metal or molded of insulating composition material like hard rubber, fiber, bakelite, and perhaps others. The box 281 has a removable cover288 through which project a rotary knob 288 and a pair of push buttons 288 and 281. The knob 288 is connected to the outer end of a rotary shaft 282, on which an insulating sleeve 282' is fixed. A contact member 283 is attached to a disk 288 at one end of sleeve 282', and this contact member comprises oppositely extending arms 284 and 288. The box 281 carries two pairs of insulated contacts 288-281 and 288-288. When the pointer 288' of knob 288 is in radio position (see Fig. 28), the switch arm 284-285 engages the pair of contacts 288-281 (Fig. 1(8). Whenthe pointer `288' is turned to fl1m" position, the arm -284-285 engages the other pair of contacts 288-288 (Fig. 17). When the knob 288 1s turned to neutral or off position, the switch arm 284-285 rests against a pair -of insulated studs or stops 388 midway of the associated contacts, as indicated by the dotted line 284' in Fig. 17. The push button 288 is connected to a switch arm 381 through an insulating pin or stem 382. The switch arm 38| may simply be a flat spring blade mounted at one end. on a block 383 in the control box. The inherent set or tension of spring arm 38| keeps it normally out of engagement with a fixed contact 384 attached to the bottom of box 281. The other push button 281 is mounted on an insulating stem 385 which is connected to a spring blade or other form of movable switch arm 388 mounted similarly to switch arm 381. The spring blade 386 is normally out of engagement with an associated contact 381.

The remote control box 281 carries a pin or stud 388 on which a bellcrank 388 is pivoted. 'Ihe lateral arm 318 of bellcrank 388 is arranged to be `actuated `by a cam 311 fixed on shaft 388. The other arm 312 of bellcrank 388 is connected at its free end 312 to a contracting coil spring 313, which normally tends to rock the bellcrank clockwise and hold it in the position shown in Fig. 16. When the switch arm 284-285 connects the pair of contacts' 288-281 (which happens when the hand knob 288 is in "radio" position). the tensioned spring 313 holds the end 312 of bellcrank 388 out of the path of switch arm 381, so that the button 288 is free to be pushed in. However, when the knob 288 is turned `to film position, the cam 311 engages the lateral arm 3-18 and rocks the bellcrank 388 counterclockwise, whereby the free end 312' of the bellcrank is moved between the switch arm 381 and a fixed lug or post 314, as shown in Fig. 19. The switch arm 381 is thus locked in normal open position. As will appear later, the function of switch arm 381 is to close the circuit of motor 33 for operating the tuning shaft 16 as long as the push button 288 is held down. Therefore, when the knob 288 is set to film position, it is impossible for anyone to operate the station-selecting button 288. The lateral arm 318 of bellcrank 388 is preferably provided with a notch 315 adapted to be engaged by the tip of cam 311 to hold the bellcrank 388 safely in locking position, as will be clear from Fig. 17. The bell-crank 388 and cam 31| are preferably of insulating material or are otherwise insulated from the contact elements in the box. A cable 318 leading out of the remote control box contains all the wiring necessary to connect the mechanism in the box with the radio receiver. The wires of cable 318 are at low tension, so that all dangers incident to high voltage are eliminated.

Referring to Figs. 16 and 17, the shaft 282 carries an arm or extension 318, which is connected by a flexible member 328 to the magnetic core 321 of the solenoid coil 251. The flexible inember 320 passes around a pulley 322 and a suitable guide 323 prevents the exible member from leaving the pulley. The solenoid coil 251 is rigidly supported in box 281 in any practical way and its function is to lmove the switch arm 294-295 to open position. The ilexible connection 320 may be a small cable, chain, tape and the like. The solenoid core 32| isA provided with 4a collar 324 which strikes one'end of coil 251 to limit the movement of the core when the 4coil is energized. The switch arm 294-295 is free to be moved to any one of its three positions without interference from the flexible connection 320. When the switch arm 294-295 is in fllm" position, as indicated in Fig. 1'1, the flexible member 320 is taut and holds the magnetic core 32| withdrawn from 'coil 251. When this coil is energized, it pulls in the core and thereby rocks the shaft 292 counterclockwise until the switch arm 294-295 is in neutral position 294. It was previously explained in connection with Fig. 13 that the solenoid coil 251 is automatically energized when the end of the last sound track on lm 12 is reached. The opening of switch arm 294-295 turns off the current for all electric devices in the cabinet. The movement of switch arm 294-295 from. lm to radio position does not disturb the magnetic core 32|, because the iiexible member 320 merely becomes slack, as indicated in Fig. 16. Any other practical connection between the electromagnetic device 251-32l and the switch arm 294-295 may be employed to open the switch when the sound lm is through playing.

The remote control box 281 contains a `voltmeter or potentiometer comprising a permanent iield magnet 325 and a coil 326 mounted on a rotary spindle 321. The cover 288 of the box has an opening 328 covered by a window 329, which carries a station dial or scale 330. A pointer 33 connected to spindle 321 terminates just below the dial 339, which is a duplicate of the radio receiver dial i9. The movable pointer 33E is normally held in zero position at one end of dial 330 by a pair of opposite'ly acting spiral springs 332, as is usual in electric measuring instruments. The spindle or coil shaft 321 is journaled at its ends in a non-magnetic frame or bracket 333 attached to the pole pieces 334, which form a cylindrical airgap for the swinging coil 325. The magnet structure as a whole is secured in the box by screws 334 or otherwise. When current passes through coil 323, it swings clockwise through an angle depending upon the strength of the current. As I shall presently explain, the intensity of the current passing through coil 323 is controlled by a rheostat operatively connected to the radio tuning shaft l5.

Referring to Fig. 14, one side of the potentiometer coil 325 is connected by a wire 335 to the low voltage conductor 253, and the other side of the coil is connected by a wire 335 to one end of a resistance element 331 in the radio receiver. The tuning shaft i3 has mounted thereon (or otherwise operates) a contact arm 333 arranged to engage the stationary resistance element 331 and electrically connected to the low voltage conductor 255. When the tuning shaft i5 is rotated in either direction by the electric motor 33, the rheostat arm 333 moves slowly over the resistance 331 and thereby varies the current strength in the potentiometer coil 325. When the shaft i5 stops in tuning position for a selected station, the rheostat arm 333 causes a current of tuned in. In other words, when the operator holds the remote tuning button 290 pushed in,

^ the pointer 33| in box 281 moves over the scale 330 in synchronism with the movements of the station indicator in the radio cabinet. If desired, a small electric lamp may be placed in the box to illuminate the transparent or translucent scale 330 during the tuning operation, or as long as the receiver is on. I

In Fig. 14 the movable switch arms 30| and 306 are connected by wires 339 and 340 to one side of the solenoid coils 54 and |86. The other side of these coils is connected to a common wire 34| which leads to one terminal of the electric motor 33. A Wire 342 connects the other motor terminal to the low voltage conductor 255. The stationary contacts 304 and 301 in the remote control box are connected by wires 343 and 344 in Aparallel to the low voltage conductor 256. The

fixed contacts 296 and 298 are connected by wires 345 and 346 to one side of the solenoid coils 205 and 203, respectively. The other two contacts 291 and 299 are connected in parallel to a wire 341 whichv goes to one side of a relay coil 348. The other side of coil 348 is connected by a wire 349 to the main conductor 252. A resistance element 350 is inserted in wire 241 to cut down the voltage through relay coil 348 as required. The relay coil 348 is mounted on a magnetic frame 35| which carries a movable armature 352. For convenience I have shown the armature 352 in the form of a switch arm connected to a wire 353 which leads from the circuit main 253 (or switch arm 229) to a wire 353'. A contracting coil spring 354 normally holds the armature or switch arm. 352 against a fixed stop 355 out of engagement with a fixed contact 355.

It is seen from the above description that the low voltage relay switch 352-356 is in shunt to the on-off switch 22S-23| which is adapted to be closed by the hand knob 29, as already explained. When the relay coil 348 is energized by turning the remote control knob 289 to radio o'r film position, the armature 352 is attracted to the magnetic frame 35| and engages the switch contact 356, so that the electric power is turned on for all devices in the cabinet, even if the switch arm 229 is open. The switch arm 294-295 is connected by a wire 351 to the main conductor 253, and the wire 353 connects the wire 351 to one side of the voltage-reducer 254. A wire 358 connects the main conductor 252 to the other side of the voltage reducer 254, and a wire 359 connects the low voltage conductor 255 with one side of coils 204 and 205. A wire 360 leads from the low voltage conductor 253 to wire 351 between the connecting points 35| and 352. From point 353 in conductor 256, a wire 334 leads to contact 2i5 on the pivoted arm 2M, and a wire 365 connects the associated stationary contact 239 to wire 33|.

When the knob 289 on the remote control box is in oi position, all circuits are open. Let us suppose that a person wants to operate the lm phonograph from the remote control box after themachine has been loaded with the desired film.. By simply turning the knob 235 to film position; the circuit of relay coil 343 is closed through main conductor 252, wire 349, coil 343, wire 341, closed switch 299-295 and through wire 35i to the return main 253. The energizing of relay coil 343 closes the main power switch 352-353 and places the amplifying system in operative condition. The terminals 355 are sup-

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