US2069595A

US2069595A - Recording and reproducing apparatus

Info

Publication number: US2069595A
Application number: US351240A
Authority: US
Inventors: Adolph A Thomas
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1929-03-30
Filing date: 1929-03-30
Publication date: 1937-02-02
Anticipated expiration: 1954-02-02

Description

Feb. z, 1937.

RECORDING AND REPRODUCING APPARATUS Filed March 50, 1929 4 Sheets-Sheet l INVENTOR WKM'W A. A. THOMAS y 2,069,595

Feb. 2, 1937. A. A, THOMAS RECORDING AND REPRODUCING APPARATUS Filed March 30, 1929 4 Sheets-Sheet 2 Feb. 2, 1937. A, A, THOMAS y 2,069,595

RECORDING AND REPRODUCING APPARATUS Filed March 30, 1929 4 Sheets-Sheet 3 INVENTOR y Patented Feb. 2, 1937 UNITED sTATEs RECORDING AND REPBODUCING APPARATUS Adolph A. Thomas, New York, N. Y., assigner to Radio Corporation of America, New York, N. Y., a corporation ofDelaware Application March 30, 1929, Serial No. 351,240

18 Claims.

This invention relates to the art of recording and reproducing sound and other vibrations by optical methods in which a s trip of lm is subjected to variations of light in accordance with,

transmitted vibrations. In sound lms heretofore made, there is but a single sound track running lengthwise of the lm, either along the Acenter or (as in talking movie films) along one edge of the picture.

According to my invention, I 'multiply the capacity of a sound film by recording thereon in two or more tracks, which are played alternately in reverse directions when the film is unwound and rewound. When the end of a track is reached, automatic mechanism controlled by the film is itself brought into action to accomplishY two things: first, to vestablish operative relation between the optical recording or reproducing device and the next sound track; second, to reverse the driving connections of the reels. I also provide means forv automatically stopping the lm when the end of the last sound track is reaohed, so that when the machine stops playing, the film is fully rewound, ready to be put away or played `over again.

My new reproducing machine is particularly useful as a household phonograph, as it can be embodied in a small cabinet. I dispense with disk records, turntables and stylus reproducers with their attendant disadvantages. The multiple-record film of my invention may be of any length Within practical limits, and therefore of greater capacity than the combined tracks on a large double disk record. Then, too, lms on spools are more durable, more safely shipped and more easily stored than the disk records heretofore used.

The novel features and practical advantage of my new recording and reproducing apparatus will be understood from a description of the accompanying drawings, in which Fig. l shows a vertical cross-section' of a lm phonograph embodying my invention, the section being taken on line I--I of Fig. 2;

Fig. 2 is a plan of the machine;

Fig. 3 represents a horizontal sectionon line 3-3 of Fig. 1; i

Fig. 4 is a vertical section approximately. on the broken line 4-4 of Fig. l; f

Fig. 5 illustrates, on an enlarged scale, certain details of the optical translating device associated with the film, this view being partly in section on the broken Vline 5-5 of Fig. 6;

Fig. 5a. is a detail of Fig. 5 on an exaggerated scale; L

Fig. 6 represents a plan view on section line 6--6 of Fig. 5; v

Fig. 6a is a detail of Fig. 6 on an exaggerated scale;

Fig. l is a sectional view on line 'I-'I of Fig. 6, showing the switch rollers -controlled by the film;

one end of the film;

Fig. 9 shows the other end of the nlm; and

Fig. l0 is a diagram of circuits controlled by the film.

A suitable outerl case or cabinet Ill has a top board I2 and a base I3, which are spaced to provide a chamber I4 for containing the driving mechanism of the machine. The top board I2 and base I3 carry a pair of vertically aligned Y bearings I5 and I6 for supporting a rotary shaft I'I. Bevel/gears I8 and I9 are mounted idly on shaft Il and arranged to mesh with a bevel pinion 20 fixed on the driving shaft of a suitable prime mover 2I. This is preferably a small electric motor, D. C. or A. .C. type, fixed on the base or bottom plate I3 of the cabinet. A slidable clutch sleeve 22 is mounted on shaft Il between the bevel gears I8 and I9. The clutch sleeve 22 always rotates with shaft II, but it is slidable thereon into locking engagement with either of the gears I8 and I9. For this purpose, the ends of clutch 22 are provided with teeth 23 adapted to mesh with teeth 24 and 25 projecting from the bevel gears I8 and I9. It may be assumed that, when the clutch 22 engages the teeth of gear I8, the driving shaft I1 runsv in a forward direction, and when clutch 22 is moved into engagement with the teeth of the lower gear I9, the rotation of shaft I1 is reversed.

The reversing clutch 22 is operated by an arm or lever 26 pivoted at 21 on a suitable stand or bracket 28 xed on base I3. A simple wayto connect Athe clutch 22 with the actuating lever 26 is to provide one end of the latter with a yoke adapted to engage in a slot or groove 29 in the clutch. The rear end of lever 2B is in the form of (or otherwise carries) an armature 30 arranged between the cores of a pair of solenoids or electromagnets 3| and 32. It is clear from Fig. 1 that, when solenoid 3I is energized, the front end of lever 26 is rocked up to move the clutch sleeve 22 into engagement with-the upper bevel gear I8. When solenoid 32 is energized, the armature 30 is .drawn up and the front end of lever 26 moves down to throw the clutch sleeve 22 into engagement with the lower bevel gear I9, whereby the Fig. 8 is a fragmentary view on the broken line 8-8 of Fig. 6 to show certain features at Y form of a lever 58 pivoted at 59 and having a pair rotation of shaft I1. is reversed. A spring arm 33 has a cam head 34 arranged to engage the rear end of lever26 to hold the same ilrmly in either actuated position. 'I'he lower end of spring arm 33 is mounted in a boss or bracket 35 carried by the base l| 3, which also supports the lower solenoid 3|. If the solenoids 3| and -32 are 'continuously energized while the shaft I1 is running, the holding arm 33 is not necessary. 'Ihe upper solenoid 32 may conveniently be mounted on a bracket 38 secured to a side wall ofthe cabinet.

The top board I2 4carries four

rotary shafts

31, 38,39 and 40. lThe two

shafts

31 and 38 project above the top board I2 and are adapted to support a pair of nlm spools-or reels 4| and 42. Lugs 43 may be pivoted to the upper ends of

shafts

31 and 38 to hold the spools 4| and 42 firmly inplace, while at the same time permitting their easy removal and' insertion. The upperends of the two

intermediate shafts

39 and 48

carry sprockets

44 and 45, which engage the sprocket holes 48 of film 41` for driving the same at predetermined speed. according tostandard practice. Each sprocket wheel.has associated with it several rollers 48 to guide the film vproperly over the sprockets, as is usual in motionpicturemachines. Fig. 2 indicates clearly the path of film 41 in passing from one spool to the other. The sprocket shafts 38 and carry at their lower ends a pair of gear.

wheels

49 and 50 arranged in mesh with a pinion 5| fixed on the vertical driving shaft I1. I'he transmission ratio between. pinion 5| and sprocket gears 49 and 5I) -is such. that the sprocket shafts 39 and 4I) are driven at the correct speed. It is hardly necessary to add that the drawings are not intended to show this transmission ratio with mathematical accuracy.

'

I'he spool shafts

31 and 38 are provided at their lower ends with

grooved pulleys

52 and 53. which always rotate with the shafts. The lower ends of

sprocket shafts

39 and 48 carry

grooved pulleys

54 and 55, which in this case are smaller than the

pulleys

52 and 53. Elastic bands or

belts

58 and 51 connect the pairs of pulleys 52-54 and 5353.

'I'hese elastic belts, which may consist of rubber,v

rubberized leather, coll springs and the like, are so adjusted that normally they permit slipping on the 4pulleys, 52-54 and .S3- 55. However, one of the belts is always held taut to establish a positive drive between the connected pulleys. In the present machine I employ a belt-tightener in the a of diverging

arms

60 and 6| which carryrollers 82. The lever 58 has an extension 83 which comprises-or carries an armature arranged between a pairof solenoids y84 and 65. A bevelled spring arm 86 may be used to hold the lever 58 in either of its actuated positions. The

solenoids

64 and 88 may conveniently be mounted on brackets 81, secured to the adjacent wall or panelv 88, which also carries a bracket 69 for supporting the lever 58.

It is rclear from Fig. 3 that, when the solenoid 85 is energized, the lever 58 is rcked clockwise (as viewed in -that figure)y and the roller 83 of.

arm- 5| tightens-the belt 51, so that a direct posi- 'tive drive is established between the sprocket shaft 48 and the spool shaft 38. It is assumed that, when the belt 51 is tightened, the spool 42 is rotated in the direction of arrow 18 to unwind the iilm from spool 4|. When the solenoid 84 is f energized, the lever 581s rocked the other way and the roller 62 of arm 88 tightens the belt 88 to establish a positive drive between the sprocket shaft' 39 and the spool shaft 31. This occurs duringthe reverse rotation of the vertical shaft I1 to rewind the film on spool 4|.' When the belt 51 is tightened during the forward movement of the film, the belt 58 is suiliciently loose t`o permit the sprocket wheel 44 to unwind the film from spool 4| as required. When the belt 58 is tightened during the rewinding of film 41, the slack belt 51 allows the spool 42 to rotate at a variable rate ments of lever 59 from one position to the other take place automatically at the proper moment, as will later be explained.

of speed for unwinding of the film. v The move' l The film 41 carries a pair of 4sound tracks or bands 1| and 12, which are indicated merely-in a diagrammatic Way and extend substantially parallel along the edges of the lm. Looking at Figs. 9 and 8, which show the beginning and end portions of the film, the upper sound track 1|l begins at 13 and ends at 14, while the other sound track 12 begins at 15 and ends at 16. In other words, the two sound tracks are arranged reversely, the second track beginning where the ilrst track ends. track 1| is played during the forward movement or unwinding of the nlm, the sound track 12 is played during the reverse movement or rewinding of the lm. In the broader aspect of this invention, the flexible record member 41 may be a thin steel tape, and the sound tracks 1I and 12 may be recorded magnetically in a. manner well understood by those familiar with this art. I prefer.' however, to make the member 41 in the tracks II and 12 are produced by optical methods well known to the acoustic engineer. The lm 41 is provided near its ends with

longitudinal slots

11 and 18, which are arranged approxi- If we assume that the sound form of aphotographic film on which the record mately at the center and spaced a short distance and 6. 'I'his box may conveniently be made of sheet metal and fixed in proper position to the top board I2 by screws 80 or otherwise. A transverse partition 8|. in the box provides a lightproof chamber or compartment 82 in which a photoelectric cell or tube 834 is mounted. It will not benecessary to show or -describe the inside construction of tube 83, because several types of photoelectric cell are available 4in the market, and their construction and operation are fully understood by electrical experts in this particular field. I need only mention that the cell 83 is in the form of a vacuum tube adapted tobe inserted into a base or socket 84 in compartment 82. The box 19 is provided with a small .light-proof chamber '85 containing a lamp 86 and a reflector 81. The latter is preferably adjustable by being mounted on a screw rod 88 which carries a setscrew 89 and as coil spring 9|). Whenv the setscrew 89 is turned one way or the other, the retiector 81 is moved axially toward or away from the lamp 86, the spring 99 holding the reflector firmly in adjusted position. If the reflector 81 is made spherical', there is no harm in its being it with lateral iiaiiges 95, which arev attached to 75 the side walls of lamp chamber 85 by solder, screws, rivets or otherwise. The section 96 of partition 8| has an opening 91 of considerably greater area than the

slits

92 and 93.

The box 19 is provided at opposite sides with a pair of aligned slots 98, through which the nlm 41 passes. The slots 98 arevpreferably arranged in line with the narrow space 99 that separates the

plates

94 and 96, as will be clear from Figs. 6

and 6a. The lm 41 is thus arranged between the double slit SI2-93` of lamp chamber-85 `and the opening 91 of cell chamber 82; Consequently, the rays of light from lamp 86 are controlled by lm 41 before they strike the photoelectric cell 83. It is importantl that only one sound track shall be in operative position at one time, and for this purpose I provide a shutter |00 arranged to move up and down in the space between plates 9| and 94. The top board 2 of the cabinet has a slot IOI`through which the shutter extends. Antifriction rollers |02 may be provided to assist in guiding the shutter and facilitating its movement. The shutter |00, which is made of suitable sheet material, has a short narrow slit |03 in line with the` longer slits 92 and 93. When the shutter |00 is in upper position, the slit |03 guides the light rays from lamp 86 through the upper sound track'1l, while the lower sound track 'I2 is cut off from all light. This means that the action of photoele'ctric cell 83 .i's' under the control of sound track 1I during the forward run of the lm.

When the shutter |00 is moved down, the slit 03 is in line with the lower sound track 12, while the upper sound track 1I is now optically inert. Therefore, in the lower position of shutter |00, the photoelectric cell 83 is under the control of sound track 12 during the rewinding of the film. The

slits

92 and 93 are sufliciently long to be optically connected by the shutter slit |03 in either position of the shutter. The light opening 91 in partition 8| is large enough to permit the passage of light to cell 83 through either of the sound tracks. In Fig. 5, the dash-dot lines |04 represent roughly the path of the light rays that reach the photoelectric cell 83 when the slit in shutter |00 i's raised in line with sound track 1|. The dotted lines |05 are supposed to indicate the path of light that strikes the photoelectric cell when the slit of the shutter is in alignment with the lower sound track 12. If desired, condensing lenses may be used in box 19 in the path of rays from lamp 86, but I have omit-ted such lenses to simplify the drawings. A hinged cover 19 permits ready access to the interior of box 19.

The shutter |00 is operated automatically at the right moment by a lever |06 pivoted at |01 on a bracket |08 fixed to the underside of the top board I2. The lever |06 is operatively connected to the shutter |00 in any practical way. In Fig. 5 I have shown the shutter provided with a pin |09 arranged to engage in a slot I0 at the free end of lever |06. For simplicity I have shown the lever |06 in the form of an armature or magnetic bar actuated in reverse directions by a pair of solenoids or electromagnets ||2 and II'3. A bevel-headed spring |I4 attached to the underside of top board I2 may be employed to hold the armature lever |06 in either actuated position. The solenoids ||2 and ||3 are supported in any convenient way, as by a bracket II5 secured to the top board I2. It

is clear from Fig. 5 that, Vwhen the solenoid ||3 is energized, the shutter |00 is raised to bring the slit |03 in line with 'the upper sound 'bracket is slotted at other.

track 1|. When the solenoid ||2 is energized, the lever |06 pulls the rfshutter |00 down until the slit |03 is in line with the'lower sound track 12. .The circuit of solenoid ||2 is closed automatically when the end of sound track 1| is reached, at which time the driving shaft I1 is automatically reversed, as about to be described.

The partition 8| and the walls of lamp chamber in control box 19 form two compartments ||6 and I|1 on opposite sides of the lamp chamber. The compartments ||6 and |I1 contain two pairs of contact rollers ||8 and ||9, respectively. portedin identical manner, it will only be necessary to describe the mounting of one pair. At the bottom of each chamber ||6 and ||1 is an insulating base plate |20 carrying two L-shaped brackets |2| of conducting material. Each |22 to accommodate the lower end of an arm |23 pivoted on a pin |24 mounted in the bracket and-extending across the slot, as best shown in Fig. 7. The arms |23 carry the contact rollers I I8 and I I9, which may be cut o-r stamped from sheets of brass, copper,`

heady |25' adapted to serve as a binding post..

An expanding coil spring |26 is supported between each arm |23 and screw |25 to force the associated pair of contact rollers toward each The insulating film v41,normally holds the rollers of each pair ||8 and I I9 out of contact.

During the movement of the film in either direction, the rollers ||8 and |I9 ride along the center of the lm in a path between the sound tracks 1I and 12. The springs |26 are just strong enough to push the rollers gently against ,the lm, so that they will not injure the same.

When the

slot

11 or 18 comes in alignment with a'pair of rollers, the latter are pushed by the Vsprings |26 into contact with each other to close an electric circuit. The contact rollers I9 are so positioned that, when the end of the rst sound track 1I is reached, the slot 18 comes in line with the rollers and closes certain circuits (presently to be explained) for reversing the drive shaft I1 and moving the shutter |00 downward "into operative alignment with the second sound for clearness.

The circuit connections controlled by the rollers ||8 and ||9 are illustrated diagrammatically in Fig. 10, now to be described. Main leads |21 Cil Since these two pairs of rollers are supand |28 are connected to a source of current |29,

which may be an ordinary house-lighting system. A hand-operated switch |30 may be interposed for connecting and disconnecting the leads |21 and |28. If alternating 'current is used, a suitable rectifier` |3| should be inserted in conductors |32 and |33 to supplydirect current to the various solenoids and relays. Oneof the rollers ||9 is connected to conductor |32 by a wire |34, andthe companion roller is connected by a wire |35 to one side of a solenoid or relay |36, which controls a pair of switch arms |31 and |38. The other side of relay |36 is connected by a wire |39 to a conductor |40, which in turn is connected to conductor |33. One of the contact rollers I8 is connected by a. wire |4| to one side of a solenoid or relay |42, which controls a switch arm |43. conductor |32. I might mention here that the relays |36 and |42 are of any standard make and they may conveniently be enclosedl in a box |42' (see Fig. 3). A wire |44 connects one side of .solenoid 3 with one side of solenoid 3|, and

the other side of solenoid ||3 is,connected by a. wire |45 to one side of solenoid 65. 'I'he other side of solenoid 3| is connectedvby a wire |46 to the switch arm |31, which normallyeengages a contact |41 connected-by a wire |48 to conductor |32. One side of solenoid 32 is connected by a wire |49 to switch arm |38, which is normally out of engagement with the associated contact |50 connected to solenoid |I2 by a wire |5|. The other side of solenoidl |2 is connected by a. wire |52 to one side of solenoid 64, the other side of which is connected bya wire |53 to conductor |32. One terminal |54 of the electric motor 2| is connected to the circuit lead |28, and the other motor terminal |55 is connected by a conductor |56 to the switch contact |51, which normally engages the associated switch arm |43.

It is hardly necessary to add that I have usedthe words "wire and "conductor in this paragraph to designate broadly any practical form of electrical connection, whether wire, rod, plate, or whatnot.

Let us assume that .the film 41 is running in a forward directionthat is to say, the shaft |1 is driving the

sprockets

44 and 45 in a clockwise direction as viewed in Fig. 2, so that the film is wound oi spool 4| onto spool 42. When the end 14 of sound track 1| is reached, the rollers ||9 move into contact through slot1.8 in film 41 and close the circuit through relay |36, which attracts the switch arms or armatures |31 and |38, thereby moving the arm |31 away from contact |41 and at thesame time moving the arm |38 against contact |50. The vopening of switch |31-|41 breaks the circuits of solenoids 3|, 65 and ||3, thereby releasing the associated levers 26, 58 and |06, respectively. The closing of

solenoids

32, 64 and I2, whereby these three operations take place: the lever 26 connects the clutch 22 with bevel gear I9, the lever 58 is rocked to tighten the belt 56, and the lever |06 is actuated to pull down the shutter |00 into operativerelation to the lower sound track 12. It will thus be clear' that, when the end of the first sound track 1| is reached, the driving shaft 1 is reversed and' the lower sound track 12 is subjected to the action of the optical reproducing mechanism in box 19.

The reverse movement of film 41 accomplishes two things: it winds the lm back on spool 4| and causes operation of the reproducing mechanism by means of the lower sound track 12.` When the end 1.6 of sound track 12 is reached, the rollers ||8 come into contact through slot 11 in the Ifilm and thereby close the circuit of relay |42, which moves the arm |43 away from contact |51, whereby the motor circuit is interrupted and the ilm stops.

out attention by the operator. It is assumed that when the film has stopped on being rewound, the switch |30 is thrown open, so that no current Vis wasted when the pairs of rollers ||8 and H9 engage each other after removal of the film. The main switch |30 is not intended to be closed until after a new film has been inserted in the machine.-

The movable switch arms |31, |38 and |43 are supposed to spring back to normal position as shown in Fig. 10 when the switch relays |36 and The reversing of the film when unwound v and its rewinding take place automatically with- The other side of relay`|42 is connected to |42 are de-energized. Consequently, when the main switch |30 is closed again to start a new lm, the solenoids 32', 64 arid I2 are energized to actuate the associated

members

26, 58 and |06, respectively, into normal position for the forward drive of the film. i

I have not considered it necessary to show and describe any loudspeaking mechanism controlled by the photo-electric cell 83, because the art of recording and reproducing sound photo-electrically is replete with systems of various kinds for translating sound into light variations to `form a track on a iilm and for converting this Ytrack into audible sound. Although I have shown only two sound tracks 1| and 12, it isl manifest that more than two sound tracks may be provided, depending largely on the width of the lm used. It is preferable tohave .an even number of record tracks, such as two, four, six, etc., so that the film is wound back to original position when the .machine is through playing. That puts the lm in condition to be removed and replaced by another. Although I have referred to the tracks 1| and 12 as sound tracks, itis obvious that, in the broader aspect of my invention, those tracks may represent any other type of record. The movable shutter |00 represents only one way of controlling the record tracks 1| and 12, and other expedients may be resorted to for accomplishing the same purpose. At the present time, however, I think that a movable shutter control, such as I have disclosed, is perhaps theI simplest arrangement for that purpose. I say this in a suggestive and not a restrictive sense.` When in certain claims I speak of a tape or lm having a pair of record tracks, I mean at least two tracks without' excluding the idea of more than two. I use the word tape broadly to include a magnetic band, an optical film, and perhaps other practical forms of flexible recording and reproducing ribbons.

The basic features of my invention may undoubtedly be embodied in other forms than herein set forth, `fand I therefore do not wish to be limited to the details herein described and shown in the drawings. Changes and modifications will probably occur to others without departing from the scope of the invention as defined in the appended claims.

I claim as my invention:

1. Film-controlled photo-electric mechanism having a movable shutter for changing the direction of light to the film, a source of light and photo-electric means operatively associated with the lm and said shutter, which is mountedlto move independently of said source of light, and means controlled by the film itself for automatically operating said shutter at a predetermined moment, said film-controlled means automatically resetting the shutter to initial position.

2. The combination of aphotographic film dependently of said-optical eld for shifting the light laterally ofwthe film, and electromagnetic means controlled by the iilm for automatically operating said shutter at predetermined inter- 'vals, said electromagnetic means automatically 60 movable in an optical field, a shutter movable inber and automatically restores it to initial position.

4. In acoustic apparatus, the combination of a film having a plurality of reverscly arranged sound tracks, a source of light and a photoelectric element arranged on opposite sides of said lm in operative relation thereto, mechanism for driving said film forwardly and reversely, a movable shutter for exposing only one track at a time to light rays from said source, means for mounting said shutter to move relatively to said source of light, means controlled by the iilm for operating said shutter at the end of each sound track, and means whereby the nlm-controlled operation of said shutter at the end of the last track automatically returns the shutter to initial position.

5. In acoustic apparatus, the combination of a flexible ltape having a plurality of reversely arranged sound tracks, driving mechanism for said tape, said mechanism including means for automatically reversing the movement of said tape when the end of a sound track is reached, reproducing means operatively associated with said sound tracks during the forward and reverse movements of said tape, means including a member movable independently of said tape and reproducing means for automatically subjecting said tracks successively to the action of said reproducing means, and means whereby the operation of said track-selecting means at the end of the last track automatically returns said lastmentioned means to initial position.

6. In acoustic apparatus, the combination of a flexible tape having a plurality of reversely arranged sound tracks, driving mechanism for said tape, said mechanism including electric means controlled by the tape itself for automatically reversing the movement of sa'idtape whenlthe end of a; sound track is reached, reproducing means operatively associated with said sound tracks during the forward and reverse movements of said tape, means including a member movable independently of said tape and reproducing means for automatically subjecting said tracks successively to the action of said reproducing means, and-means whereby the operation of said track-selecting means at the end of the last track automatically returns said last-mentioned means to initial position.

7. In acoustic apparatus, the combination of a iilm having a plurality of reversely arranged sound tracks, a source of light and a photoelectric element arranged on opposite sides of said lm in operative relation thereto, said nlm and the associated optical members being held against relative movement laterally of the lm, mechanism for driving said film forwardly and reversely, meanswhereby light rays from said source pass only through one sound track at a time during the forward and reverse movements of the film, said means including a member movable independently of said source of light, and means for automatically causing said trackselecting means at the end of the last sound track to be inoperative position for the ilrst sound track of the next film.

8. An electric phonograph comprising mechanism for running a length of sound illm from one spool to another, an electric motor for operatreproducing device operatively associated withsaid lm, said device including a stationary source of light, a shutter movable relatively to said source of light ,for exposing `one of ,said tracks to the action of said device during the forward run of said film, said shutter being movable independently of said reproducing device, electromagnetic means for reversing the oper'- ation ofsaid mechanism to rewind the lm, switch contacts controlled by one o -said slots for actuating said reversing means when the end of the rst track is reached, means controlled by said `switch contacts and slot for operating said shutter to expose the second sound track to the action of said reproducing device during the return ,movement of said lm, and other switch contacts controlled by the other slot for stopping said motor and said mechanism when the end of the second track is reached.

9. The combination of a photographic lm movable in an optical lield, a slidable shutter for shifting the light laterally of the lm, means for mounting said shutter to move independently of said optical eld, and means controlled by the lm itself for operating said shutter at predetermined intervals and automatically restoring it to initial position.

-10. The combination of a photographic film supported for operative movement, said film bearing a plurality of substantially parallel record tracks, means for providing an optical eld for said iilrn, a shutter movable independently of said optical field'for shifting the light from" `one track to another, and means'for autol matically operating said shutter when the end of a track is reached, said operating means automatically restoring the shutter `to initial position at'the end of the last track.

11. The combination of a photographic nlm having a plurality of record tracks arranged in reverse relation, an optical field operatively associated with said lm, means for driving said lm through said eld in alternately opposite directions, a shutter movable relatively to said optical eld and automatically operated at each reversal of the iilm for shifting the light from one track to the next, and means whereby said shutter at the end of the last track is automatically restored to initial position.

12. The combination of a photographic film supported for operative movement, said film bearing a plurality of substantially parallel record tracks, means for providing an optical field for said lm, a shutter movable relatively to said optical eld for shifting the light from one track to another, and electromagnetic means controlled by the lm itself for automatically operating said shutter when the end of a track is reached, said electromagnetic means automatically restoring the shutterto initial position at the end of the last track.

13. In acoustic apparatus of the class described, the combination of a sound lm supported for movement in either direction andhaving a slot near each end,.reproducing means controlled by said film, two pairs of switch members associated with said iilm, each pair of said 'members normally engaging opposite sides of said film and being held thereby in open position, each of said slots causing one pair of switch members to engage and close an electric circuit, means controlled by one pair of said members for reverstracks, optical reproducing mechanism associated with said film, means for moving the lm through the optical eld of said mechanism, a shutter 4movable independently of said optical mechanism for exposing only one track at a time to said mechanism, electromagnetic means for operating said shutter, switch means controlled by the iilm for venergizing said electromagnetic means when 4the end of ea'ch sound track isreached, and

means whereby said film-controlled operation of the shutter at the end of the last sound track automatically returns the shutter to initial position.

l5. In sound-reproducing apparatus, the combination of mechanism for driving a sound film which carries a plurality of reversely arranged rrecord tracks, said mechanism including means for automatically reversing the direction of movement of said film when the end of a sound track is reached, an optical reproducing device associatedwith said iilm, a shutter mounted to move independently of said device for exposing only one track at a time tothe action of said device, means controlled by the film when mov-Y ing in either direction for automatically operating said shutter at the end of a track, and means whereby said nlm-controlled operation of the shutter at the end of the last sound track automatically returns the shutter to initial position.

16. The combination of a-statonary source of light, a stationary photo-electric cell, a film movable lengthwisebetween said elements and provided With a plurality of record tracks, means for preventing relative lateral movement of said source of light and said lm, means for directing light rays from said source to said cell through said film tracks, said means including a movable member adapted to direct light rays through one record track at a time, said member being movable with respect to `said light source and said cell, electromagnetic means for operating said member, and film-controlled electric connections for energizing said electromagnetic means to actu ate said member at predetermined intervals.

17. Film apparatus comprising, a stationary 10 source of light, a photo-sensitive illm, means for moving said iilm lengthwise in either of two opposite directions, means for preventing relative lateral movement of said source of light and the illm, light-directing Ameans movable relatively to 16 said source of light fordirecting said light upon said lm in a beam of a width less than the width of saidiilm, and means for relatively moving said light directing means and said lm at predetera mined time intervals for directing said light upon different longitudinal portions'of said film.

18. A vfilm apparatus comprising a stationary source of light, a photo-sensitive lm, means for llongitudinally moving said lm, means for defining -said light in a beam less in width than the width of said i-llm, means for preventing relative lateral movement of said source of light and the lm, light directing means movable relatively to said source of light for directing said beam of light upon said lm, and means for relatively shifting said light directing means and said illm at predetermined time intervals with respect to the longitudinal movement of said lm.

ADOLPH A. THOMAS. ss