US2032190A - Electric recording and reproducing apparatus - Google Patents

Description

Feb. 25, 1936. A. A. THOMAS ELECTRIC RECORDING AND REPRODUCING APPARATUS 4 Sheets-Sheet l 7 Filed July 15, 1930 Feb. 25, 1936 THOMAS ELECTRIC RECORDING AND REPRODUCING APPARATUS Filed July 15, 1933 4 Sheets-Sheet 2 Feb. 25, 1936.

A. A. THOMAS ELECTRIC RECORDING AND REPRODUCING APPARATUS Filed July 15, 1933 4-Sheets-Sheet 3 Feb. 25, 1936. A. A. THOMAS. 2,032,190

ELECTRIC REUUhp- .u AND REPRODUCING' APPARATUS Filed July 15, 1933 4 Sheets-Sheet 4 24/4 1 4 7 Z5 f zaa L (/76 INVENTOR Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE ELECTRIC RECORDING AND REPRODUCING APPARATUS I Application July 15,1930, Serial No. 468,074

6 Claims.

My invention relates-to the art of recording and reproducing sound, and its, main object is to provide a. unitary household cabinet which combines the functions of radio receiver, sound recorder, and phonographic reproducer. These various operations are selectively controllable by merely actuating a. finger piece.

One feature of my invention comprises means for. automatically recording a piece of radio broadcast simultaneously with its reproduction by the receiver through the loudspeaker. Sometimes it is desirable to make a record of an unusual broadcast number, like a song by a great artist, or the speech of afamous person. The recording is preferably done on a steel tape or wire by electromagnetic action, but it is also possible to record optically ona photographic film or mechanically on a wax record. The practical advantage of recording on a steel tape or ,wire lies in the fact that this record is permanent without further treatment and can be used immediately for reproduction through the loudspeaker of the radio receiver. The recording operation is silent and does not interfere with the normal function of the receiver, which can be used independently of the recording mechanism.

It is also possible to operate the recording mechanism of my cabinet while the receiver is cut out, although some of the receiver circuits are utilized during the recording operation. By simply throwing a switch, a person connects a telephone transmitter to the input circuit of the radio receiver, and at the same time he connects the recording device in the output circuit in place of the loudspeaker. It is now only necessary to talk or sing into the transmitter, and the sound is recorded on the steel tape, photographic fil wax record, or whatever recording device is e ployed. In this way it is easy to make really good records at home of the voices of members of the family, friends or visitors. of course, the reproducing part of the machine can be operated by records made elsewhere, so that the machine can be used like a regular phonograph. By using the circuits of the radio receiver in the recording and reproducing operations, I require but little mechanism in addition to the receiver, so that the cabinet can be made compact and at a reasonable cost.

The novel features and practical advantages of my invention will be understood from a description of the accompanying drawings, in which i Fig. 1 illustrates a cabinet containing my novel combination of radio receiver, recorder and reproducer;

Fig. 2 is a plan view of the reproducing mechanism;

Fig. 3 is a transverse view along the broken line 3-3 of Fig. 2;

Fig. 4 represents a front elevation of the re cording mechanism, sectioned in part along the line 44 of Fig. 2;

Figs. 5 and 6 are enlarged fragmentary views 10 of a recording steel tape passing between the poles of an electromagnet, the first view being longitudinally of the tape and the other view transversely thereof;

Fig. 7 is an enlarged fragmentary view showing a pair of switch arms operated by the recording tape or film;

Fig. 8 is a diagram of circuits controlled by the recording tape or film in its forward and reverse movements; and

Fig. 9 is a diagram of the interconnected circuits in the cabinet for utilizing the radio receiver during the recording and. reproducing operations.

Referring to Fig. 1, there is a cabinet C of suitable construction and design having a top board I 0 on which the recording and reproducing mechanism R is mounted for easy access. The chamber above the top board I0 is sufliciently deep'to permit closing of cover l2. Behind the front panel I3 is a radio receiver adapted to be controlled by one or more hand knobs M in the usual way. Below the receiver is a loudspeaker L of any approved type, and one either side of the loudspeaker is a compartment l5 for holding record spools or other articles. Each compartment I5 is closed by a door 15, and an ornamental grille or screen 17 covers the loudspeaker diaphragm. The particular location of the various parts in the cabinet is not important, and will obviously vary in cabinets of different design. It is probably most convenient to have the recording and reproducing mechanism R directly below the lid of the cabinet, like the turntable and pickup in ordinary phonographs.

The motorboard it) carries two brackets l8 and IQ for supporting a pair of rotary shafts 2D and 2|, on which a pair of spools or reels 22 and 23 are mounted so as to rotate therewith. The spools 22 and 23 are arranged inlateral alignment and support a recording tape or film 24, which in the present instance is supposed to represent a magnetic steel band or ribbon of such thinness as to be easily flexible for winding and unwindg ing, very much like an ordinary movie film. In fact, the tape 24 may be a photographic film on which sound tracks are recorded optically by methods well known to experts. Since 22is the original pay-out reel on which the recording tape is wound when the machine is started fer recc-rding or reproducing, it is necessary to permit I be removable, because the tape 26 is always rewound-on reel 22 when the end ofthe record track is reached, as be explained in-due course. I have therefore shown a retaining disk or washer 2| mounted on the free end of shaft 2|, but a pivoted latch like may be used if desired. t v

I shall now describe the connections for driving the spools or reel; 22 and 23 in reverse directions for unwinding and rewinding the record tape 24.

'A bracket 26 monuted on top board I8 has an upstanding arm 21 provided with bearings 28 and 28, and a second arm 38 on the bracket terminates in bearings 3| and 32. An electric motor 33 carries a bracket 34 which has a bearing 35in alignment with bearing 28, and these two bearings support a rotary shaft 36 arranged transversely cf the cabinet. The shaft 36 carries near its ends a pair of gears 31 and 38, which are secured to the shaft by cross-pins 38 or otherwise. The gear 31 is bevelled. and arranged permanently in mesh with a bevel gear 48 fixed on a vertical shaft 4| which is supported in bearing 32. A sleeve 42 rotatably mounted on shaft 36 carries at one end a gear wheei 43am! at the other end a bevel gear 44, which is-similar to bevel gear 31 and in-mesh with the vertical gear 48. A collar 45 fixed on shaft 35 prevents axial displacement of sleeve 42 on shaft 36. The motor shaft 46 carries a worm or spiral -pinion 41 arranged in permanent mesh with a worm wheel or spiral gear 48 fixed on the vertical countershaft 4|.

reduced speed. Since the bevel gear 31. is keyed to shaft 36, while the opposite gear 44 is secured to thelocse'sleeve 42, it is evident that the two gears 38 and 43 always rotate in opposite dime-- (see Fig. 3). support a rotary shaft 43 on which a clutch ring 58 slidably mounted, as by means of a key 5| or otherwise. The clutch ring carries a gear wheel 52 arranged to mesh alter= nately withgear wheels'38 and 43, depending upon the position of the clutch ring. Referring to Fig. 3, when gear 52 is in mesh with gear 43,

p the shaft 48 rotates in a direction to drive the tape or film 24 from left to right, as viewed in Figs. 2 and 4. This is the forward movement of the tape, and gear 43 may therefore be called the forward or unwinding gear: ,When the clutch gear 52 is in mesh with gear 33, the directionof shaft 48 is reversed .to rewind the tape 24 from reel 23 onto the initial pay-out reel 22. It will therefore be convenient to refer to gear 38 as the reverse or rewinding gear.

. The motor shaft 53 always rotates in the. same direction at high speed, but the bevel gears 31 and 44 rotate in oppxite directions at properly The slidable clutch ring 58 and gear 52 are adjusted to forward and reverse positions by electromagnetic mechanism comprising a pair of coils 53 and 54, which actuate a pair of magnetic cores 55 and 56 connected to the lateral arms 51 of a bellcrank 58. A post 53 on bracket 26 carrise a pivot pin 68 on which the bellcrank 58 is mounted for rocking movement in either direction. The upper end of bellcrank 58 is in the v form of a yoke or bifurcated extension 6| which carries rollers arranged to engage in an annular groove 62 of clutch ring 58. A contracting coil the clutch gear 52 into mesh with'gear 43. When the other solenoid coil 54 is connected in circuit, the bei j crank 58 is rocked the other way to the clutch gear, 52 into mesh with gear wheel'36. The two coils 53 and 54 may therefore be called the forward and reverse coils, respectively. Te

facilitate the intermeshing of clutch gear 52 ,with gear wheels 38 and 43, the teeth of these three gear members may be bevelled at the engaging edges, as shown in Fig. 3. By making these gear members of non-metallic material, such as re enforced bakelite, fiber and the like,

. the operation cf the gears ispractically noiseless.

The shaft 48 carries a grooved pulley 64, which n may be a single member with two grooves or two separate members with a single groove each. For convenience, however, I shall refer to the member 64 as a pulley having two grooves for receiving tensioned belts 65 and 66, which are preferably bands of elastic rubber, coiled springs, or the like. The pulley 64 is keyed to shaft 48 and always rotates therewith. The spool shaft 28 carries a grooved pulley 61 which. receives thedriving belt 65, whereby the spool'22 is operatively connected .to shaft 48 fer rotaticn in either direction. A

bracket 68 on top board i8 supports a shaft 69.

which carries a double grooved pulley 18. The.

rear end of the spool shaft 2| carries a grooved pulley 1| whieinis connected with pulley 18 by a tensioned belt or band 12, and the pulley 18 is connected to pulley 64 by belt-66. It is clear from Figs. 2 and 4 that the spools 22 and 23 are geared to shaft 48 for simultaneous rotation in the same direction-as the shaft. -The elastic belts 65, es,

and ?2 allow suflicient slippingto compensate for the varying speeds at which the tape 24 is wound from one reel onto the other.

The spaced parallel shafts 48 and 63 carrytape 24, so that the portion-of the tape betweenv the sprockets is fed in either direction at uniform predetermined speed, irrespective of any variations in the rate of take-up and unwinding of the The sprocket wheels 13 and 14 thus tape-by spools 22 and 23. To hold all portions of the tape or film 24 taut during the unwinding and 1 rewinding movements, I provide automatic compensating arms /16 and 11 pivotally mounted on spool shafts 28 and 2|. Each arm carries at its free end a lateral pin" for supporting a weighted roller 13 arranged tcengage the record tape 24. Any slackness in tap-e 24 due to variations in the rate of winding and unwinding is automatically taken up by the weighted rollers 10 which rise and fall as required. The rollers 19 are preferably covered with felt, rubber, or other material that will not injure the surface of tape 24.

As previously stated, the recording and repro ducing tape 24 has been assumed to be a magnetic band or ribbon on which sound is recorded magnetically. In Fig. 8 the tape 24 carries two sound tracks 80 and BI but any other number of sound tracks may be recorded. It is best to record an even number of tracks, so that the tape will be in rewound condition on reel 22 when the endof the last track is reached. This will become clear as the description proceeds. It goes without saying that the sound tracks 80 and BI are represented in Fig. 8 in a crude diagrammatic way, for the actual tracks are invisible and are nothing more than magnetic areas of varying intensity. The first sound track 80 begins at 80' and the other sound track 8i begins at 8|. This means that in recording on track 80 and reproducing therefrom, the tape 24 runs forward in the direction'of arrow 02 in Fig. 8; and for recording on and reproducing from the second sound track 8|, the tape is run in the reverse direction as indicated by arrow 83.

The electromagnetic mechanism for recording on steel tape 24 and reproducing therefrom comprises a U-shaped magnet 84 mounted in a nonmagnetic frame 85, which is slidably supported between rollers 86 projecting laterally from bracket arms 87. These arms are secured to (or cast integral with) an upright post 88 mounted on the top board I of the cabinet. The field magnet 84 is provided with a pair of pole pieces 89 arranged in axial alignment and extending toward each other. One or each pole piece carries a coil 90 adapted to be connected in a circuit of variable electric impulses during the recording operation.-

If two coils are used they are preferably connected in series as indicated in Fig. 8, but for convenience I shall consider the two coils as a single coil. The pole pieces 89 are arranged in axial alignment and may terminate in flat polar projections 9I which touch a pair of fixed nonmagneticplates 82, as best shown in Figs. and 6. The plates 92 are mounted on L-shaped arms 83, which may conveniently be secured to the horizontal bracket arms 81, as best shown in Figs. 4and 7. The L-shaped arms 93 have horizontal extensions 93 to which the guide plates 92 are secured by screws 94 or otherwise. It is immaterial how the guide plates 92 are supported. The ends of plates 92 are preferably made divergent, as indicated at 92 in Fig. 5, to facilitate the insertion of record tape 24.

The slidable frame '85 which carries the field magnet 84 has an extension 95 pivotally connected at 96 to the upper end of a bellcrank 97. The top board ID of the cabinet supports a block 88 which carries a vertical post 99, and at the top of this post is a pivot pin I00 for supporting the bellcrank 91. The lateral arms IOI of bellcrank 9i carry magnetic cores or plungers I02 which pro- 5 ject into solenoid coils I03 and I 04. A contracting coil spring I05 is connected at its upper end to bellcrank 91; and'at its lower end to the upright post 89. The tension line or axis of spring I05 is to one side of the pivot axis I00 of bellcrank 97 in either position of the latter. Consequently, when the bellcrank 87 is rocked to one side or the other, it is firmly held in either position by the tensioned spring I85. The lateral extension 95 on frame 85 is provided witha pair of spaced notches I08 and I01 which are preferably piece I36 projecting from the top V-shaped. The post 88 or arm 81 carries a latch or plunger I08, which has a bevelled lower end adapted to fit snugly into notches I08 and I01. The latch I08 is supported for vertical movement in a recess I08, which also contains a small expanding coil spring IIO for pushing the plunger I00 downward.

When the solenoid coil I03 is energized, the bellcrank 91 is rocked clockwise (as viewed in Fig. 3) to move the polar projections 9| of magnet 84 into alignment with the first sound track 80. That is to say, when magnet 84 is in the position shown in Fig. 3 during the recording operation; the record track produced by electric impulses in coil 90 will correspond to the position of track 80 in Fig. 8, and this takes place during the forward run of the tape. When the tape runs in the reverse direction as indicated by arrow 83 in Fig. 8, the solenoid coil I04 is energized to rock the bellcrank 91 counterclockwise until the springpressed plunger I08 snaps into notch I0'I. The polar projections 9I are now in position 9| (see Fig. 6) and this position corresponds to the second record track BI in Fig. 8. It is hardly necessary to say that Figs. 5 and 6 are grossly exaggerated, for the actual device is considerably smaller and the transverse movement of pole pieces 89 is only a small fraction of an inch.

The automatic shifting of magnet 84 simultaneously with the reversal of tape 24 is controlled by a pair of movable switch arms H2 and H3, which are pivoted on pins I I4 and 5 carried by bracket arms H6 and III. The arm IIS may conveniently be secured to the post or standard 88 (see Fig. 7), while the other arm III is attached to the upper end of bracket 68. The pivoted switch arm H2 is in the form of a bellcrank carrying at one end a roller I I8 and at the other end a contact I I9 arranged to engage a stationary insulated contact piece I mounted on arm H8 in any practical way. The other pivoted switch arm H3 carries at one end a roller HI and at the other end a contact I 22 arranged to engage a fixed contact piece I23 carried by an insulated strip I24, which is attached to arm II'I. Springs I25 coiled about pins H4 and H5 normally tend to rock the upper end of switch arms II 2 and H3 toward each other, so that the rollers H3 and I2! are pressed against the two edges of tape 24, as shown in Fig. 7 and d agrammatically indicated in Fig. 8. The switch arms H2 and H3 are arranged on opposite sides of the fixed guide plates 92 as close to the field magnet 84 as possible. In Fig. 8 the plane of movement of the electromagnetic recording and reproducing device laterally of tape 24 is diagrammatically indicated by the dotted line I26. To prevent even a very slight lateral movement of tape'24 under the opposing pressure exerted by rollers I I8 and I2I, the guide plates 82 may be provided with side strips I2? which just touch the two edges of the tape as it moves through the guide plates. The edges of these plates are provided with notches I28 for a purpose that will presently be expla ned. The rollers H8 and I 2| are preferably of fiber, rubber or other suitable insulating material.

Referring to Fig. 8, there is a plug I29 adapted to be inserted in a house-lighting socket and connected to a pair of leads I38 and I3I, which may include a resistance I32 for reducing the voltage, if necessary. *A switch arm I33 is actuated by a cam lever I34 pivoted at I35. A suitable finger board I0 of the cabinet is connected to cam lever I34 for moving the same to open and closed position. It is underone terminal of the electric motor 33, and the ther motor terminal is connected to a wire I38 which leads to one side of a solenoid coil I40.' The other side of this coil is connected by a wire II4I to a common terminal I42 which also serves as a binding post for wires I43 and I44. A wire [[45 connects the main conductor I30 with the central point I46 of coils I03 and I04, and a wire I41 leads from conductor I30 to the commonconnecting point I48 of clutch coils 53 and 54. A wire I49 connects one side of coil 54 with one ide of coil I04, and a-wire I50 connects one side of .coil 53 to conductor I44, which leads to the switch contact I23. The fixed contact I20 associated with the movable switch arm H2 is connected by a wire I5I, to wire I49, or to one side )f coil I04, as indicated at I52. The solenoid coil I40 has a magnetic core I53 pivotally connected to an arm I54, which is secured to (or part of) the hand-operated cam-lever I34. The manual operation of cam lever I34 to on-and-oif'positl'on is not interfered with by the solenoid core I53. The switch arms I I2 and H3, or at least the contacts H9 and I22 thereof, are electrically con-' 'nected in parallel by wires I55 and I55-.to conductor I38; A wire I51 connects the wires I38 and I45. I might explain here. that when I speak of a wire in this description, I mean any suitable conductor of electric current, whether in the form of .a wire, rod, strip, plate, or other connectingf member.

The operation of the system illustrated in Fig'. 8 is like this, whether used for recording or reproducing. Let us assume that we are recording and that the magnetic tape 24 is running in a forward direction, as indicated by arrow 82. The switch I33 is closed. and the pole pieces 88 of magnet 84 are in position to record along the invisible track 80. The rollers H8 and HI hold the switch arms H2 and H3 against closing as long as the rollers; engage the stra ht edges of the tape. The circuit ofmotor 33 is closed" through switch I33-I31, through the five coils 53, 54, I03, I04, and I40, because the switch arms H2 and H3 are open. During the recordingoperation, the coil-803s subjected to variable current impulses that represent transmitted sound. The circuit connections of coil 90 will presently be explained in detail. The current variations in coil 80 produce corresponding variations of magnetic flux across the air gap between the pole pieces 89. Asthe magnetic tape 24 is driven at predetermined uniform speed between the pole pieces 89, the flux variations produced by coil 90 are impressed permanently into the magnetic steel of the tape. The resultant record consists of an invisible line or narrow band of steel magnetized permanently with varying intensity corresponding to the recorded sound. This will be understood bythose skilled in the art without additional explanation. The magnet 84' may be a permanent magnet whose uniform field is varied by' the speech coil 90, or it may-be a corev of high magnetic permeabilitywith no normal field fiux. In the latter case; however, the] electric impulses passing through coil should be sufllciently amplified to produce flux variations of requisite strength.

, Still referring to Fig. 8, itwill be observed that the tape 24 is provided at its edges with a pair of notches I58 and I58. -When the end of the first sound track 80 is reached, the roller III on switch arm II2 snaps into notch I58 under the action of spring I25, and contact I I9 engages the adjacent contact I20. This closes the circuits of coils 54 and I04, 56 that the twobellcranks 50 and 91 are simultaneously rocked counterclockwise, as viewed in Fig. 8; The circuit of coil 54 is closed through conductor I30, wire I41 to point ,1, coil 54, wires I48 and II, across the closed switch contacts I20-II8, wires I55 and I30,and

through switch I33-I31 to the return conductor I3 'I. The circuit of coil I04 is closed through conductor I30, wire I45 to point I45, coil I04, wire I5I, and so on as above traced for coil 54. when-the bellcrank 58 is rocked counterclockwiseby the energized coil 54, the clutch gear 52 is shifted into mesh with gear 38 ,(see Fig. 3), whereby the rotation of sprocket shaft 48 is reversed, so that the tape is now driven in the direction of arrow .83 .in Fig. 8. When the bellcrank 01 is rocked counterclockwise by the energized coil I04, the recording magnet 84 is shifted laterally or thetape, so that the pole pieces 88 are now in line with the second track 8I which begins at 8I'., Therefore, during the reverse movement of tape 24, which is 'now wound back coil 53, wire I50, conductor I44, across the closed switch contacts I23I22, wires I55 and I38, across the closed switch I33I3|,- and return conductor I3I. The circuit of coil I03 is closed through conductor I30, wire I45 to point I45, through coil I03, wire I43 to point I42, conductor I44, and so on as above described for coil 53. The circuit of coil I is closed through conductor I30, wires I5I and I38, coil I40, wires I4'I but no current flows and I44, through the closed switch contacts I23--I22, and from there to the return conductor I3I, as previously traced for coil 53; The energized coil I40 pulls down the core I53 and thereby rocks the cam lever I34 out of engagement with the raised portion I33 of spring arm I33, so that .the-latter instantly flies to open position and all circuits are broken. This, however, does not happen until after the energized coils 53 and I03rock their respective bellcranks 58 and 81 to the forward position illustrated in Fig. 8. Consequently, when the machine stops at the end of the recording or reproducing oper-; ation, the parts'are' in position for the'forward run of the next tape. The switch lever I34 remains inopen position until closed by hand. The notches I28 in guide-plates 92 permit the rollers .I I8 and .I2I to'snap into the notches I58 and I59 of tape 24. After the tape 24 has once been started in its forward run, the operator need pay no attention to the machine, because the tape is automatically reversed at the end of the first sound track and is automatically stopped when the end of the last track is reached.

I6I represent two stages of audio-frequency amplification, and that the loudspeaker L is connected tothe final output transformer indicated as a-whole by T. This transformer comprises a primary plate coil I62 and two secondary coils I63 and I64. The secondary coil I63 is connected to the electromagnetic driving unit I65 of the loudspeaker through wires I66, I61 and I68. The wire I61 is connected to a movable switch arm I69 and wire I68 is connected to a stationary contact I10, which normally is engaged by switch arm I69. In other words, the circuit of loudspeaker coil I63 is normally closed. The secondary coil I64 may be called the recording output coil, because itis operatively connected to the speech coil 90 during the recording operation. One side of coil I64 is connected by wire "I to a switch arm I12, which normally engages a stationary contact I13. The other side of coil I 64 is connected by wire I14 to a switch arm I15, which is normally out of engagement with the associated stationary contact I16. A wire I11 connects contact I16 with a switch arm I18, which normally engages a stationary contact I19. The switch arm I18 is also adapted to connect a pair of stationary contacts I90 and I8 I. One side of speech coil 90 is connected by wire I 92 to contacts I19 and IE0, and the other side of that coil is connected by wire I83 to one side of the grid circuit in amplifier stage I60. A wire I84 connects the other side of the grid circuit in amplifler'stage I 60 to switch contact I M. It is clear from this that when the switch arm I18 is actuated to close contacts I 80-I III, the speech coil 90 of the recording and reproducing mechanism is shunted across the grid input coil I 85.

.Still referring to Fig. 9, there is a telephone transmitter I 86 connected at one terminal by a wire I91 to one side of plate coil I88 in amplifier stage I60, and the other terminal of the transmitter is connected by wire I89 to a stationary contact I96. The telephone transmitter I86 may be of any approved type or make, as electromagnetic, microphonic, or electrostatic. A movable switch arm I9I associated with contact I90 is connected by wire I92 to the other side of plate coil I66, so that the closing of switch I 90-I In connects the telephone transmitter I86 in shunt across the plate coil. The two terminals I93 and I99 at the bottom of Fig. 9 are supposed to be connected to the antenna circuit of the radio receiver, and these terminals are connected by a pair of normally closed switches I95-496 and I91-499, which are connected in series by wire 99. The switch members I95 and I91 are movable arms normally engaging the associated contacts I96 and I98. When either of these switches is open, the electric connection between terminals I93 and I96 is broken and the radio receiver system is disconnected from the antenna. The reason for this will presently be explained. The three switch arms I9I, I69, and I95 at the left of Fig. 9, and the three switch arms I12, I18 and I19 atthe right of the figure, may each consist of a single spring blade which is normally held by inherent set or tension in the position shov n in the drawings. That is to say, the two left spring arms I69 an I95 and the two right spring arms I12 and I91 normally engage their associated contacts. The spring arm I18 normally engages contact I19 while outof engagement with the adjacent pair of contacts I 80--I 8| The six spring blades referred to are each provided with a hump or cam projection 200, but the spring arm I15 carries an insulating block 20I with a V- shaped cam groove 202.

The four switch arms I9I', I69, I15, and I95 at the left of Fig. 9 are simultaneously controlled by a pivoted lever 203 adapted to be operated by a finger piece 204, which is supposed to-be located in a convenient position on cabinet C. It may be assumed that the switch-operating lever 203 is of the snap-over type, which moves quickly from one position to the other to make and break the circuit. The lever 203 occupies three positions,

as indicated bysuitable notations on the cabinet adjacent the finger piece 264. In normal or ofi position of lev'er 203, the switch arms I9I, I69,

I15, and I95 are in the position shown in Fig. 9. I

When the finger piece 204 is moved to Home recording position, the tip of lever 203 is swung to the left and engages the humps 200 of arms I9I, I69, and I95, and also engages the cam block 20I of switch arm I 15, so that these four switch arms are simultaneously depressed. The result of this operation is the closing of switches I90--I9I and I15I16, and the opening of. switches "59-410 and I95-I96. When the finger piece 204 is moved left to Radio recording position, the

only switch arm actuated is I15, because the V- shaped groove 202 of cam block 20! causes this arm to be moved to closed position when the lever 203 swings either way. The movements of lever 203 are limited by stops 205 or otherwise.

The three switch arms I12, I18, and I91 at the right of Fig. 9 are simultaneously operated by a pivoted lever 206, which is controlled by a suitable finger piece 201 projecting from the cabinet. Stops 208 limit the movement of lever 206 in either direction. As'long as the finger piece 201 remains in off position, the switch arms I 12, I18, and I91 engage their respective contacts I13, I19, and I98. When the finger piece 201 is apped to on position, the lever 206 swings to the left and engages the humps 206 of the associated switch arms, which are thereby moved to open position. When the switch arm I18 is depressed, it connects the adjacent contacts I80 --IBI to connect the speech coil 90 across the input coil I85 of the radio receiver. It will be understood that the arrangement of the seven switch arms in Fig. 9 is merely diagrammatic, so as to facilitate the drawing of the circuit wires. In the actual device, the four switch arms at the left may be arranged side-by-side on a single insulating block, so as to be operated simultaneou'sly by cam lever 293. The same remark applies to the three switch arms at the right of Fig. 9 and the associated cam lever 206.

When the finger pieces204 and 201 are in normal oii position, the" recording and reproducing mechanism is disconnected and the receiver operates in the usual way to reproduce the re: cei'ved broadcast through the loudspeaker L. Let us suppose that a person wants to make a record of a certain broadcast number. Assuming that the recording apparatus is loaded with a recording tape or film, it is only necessary to snap the finger piece 204 to Radio recording position, whereby the switch I15-I16 is closed to connect the speech coil 96 of the recording mechanism in circuit with the secondary output coil I64. This circuit may be traced as follows: starting at one side of coil I69, through wire I II across the closed switch I12I13, wire 209, coil 90, wire I82, contact I19, switch arm I18, wire I11, across the nosed switch Ila-I15, and through wire -ords, a person' moves the finger piece 204 to 514 back to the other side of coil I64. The amplified impulses the primary output coil I62 induce corresponding impulses in the secondary coils I63 and I64 for simultaneously actuating the loudspeaker L and the recorfing mechanism. Therefore, while the loudspeaker is audibly reproducing a. broadcast reception; the recording mechanism is silently making a record of what is heard through the loudspeaker: To stop the recording operation, the finger pice 204 is moved to of! position.

It is also possible to operate the recording mechanism to make a record of speech or music originating in the home? In this case the transmitter I86 is used in the same way as when a person talks or sings intc 'a telephone. The transmitter I86 may be located at any distance from the recording apparatus. For making home rec- Home recording: position, whereby the transmitter I86 is connected across the gridinput coil I85 and t@ loudspeaker L is disconnected; As previously explained, when the finger piece 204 ismovedto Home recording position, the cam lever 203 closes the switch arms I9I an'ct' J15, and at the same time opens the switch arms ,"I68 and I85. The opening of switcharm I95 in terrupt-s the connection between terminals I83 and I94; so that the radio receiver is disconnected from the antenna circuit and. is in no condition to receive any broadcast. The closing of switch I80-I8I connects the telephonetransnritter I 86 across the plate coil I88, so that the current impulses produced by the vibrations of the transmitter diaphragm are superimposed upon the normal plate current in coil 2I88. These impulses are amplifledthrough one or more stages until they reach the final output coil I62. The

opening of switch I 68I|0 breaks the circuit of loudspeaker coil I63, so that the loudspeaker is .out of commission duifing thejrecordin'g opera:-

tion. The-secondary ieoil I84,fhowevef, is con-'- nected in circuit with speech coil 90, because the switchII'IS-l" now closed. Therefore, the

amplified current impulses in plate coil I62 induce corresponding impulses in secondary coil I64 to energizethe speech coil 90, which records.

the electric .inipulses on the moving tape or film- 24, as previously explained. f

After a reccrd'has been made 'in the manner" above described,- a person can reproduce the recorded waves through loudspeaker L by merely shifting the fingerpiece 201 to on position, whereby the normally closed switches "2-513, II81I'I9, and I9II8,8-are automati- I I cally opened, and the normally open contacts I 80--i8I are connected by switch arm I18 .The opening of switch II2'I13 cuts the secondary recording coil I64 out of circuit, and the opening 'of switch I9II98 disconnects the radio receiver from therantenna. *The closing of contacts I80 -I8I connects the speech coil 80 'across the input coil I85. Consequently; when the tape or film 24 is run through the machine, the previously made recordproduees electric current impulses in coil 90, and these impulses are impressed upon the grid circuit of amplifier stage I60. The op.-

eration of the receiver system is the same as it the electric impulses in coilv 80 'had been receivedfrom the antenna. The impulses generated in; coil .80 by the record'on the tape or film 24, are sufiiciently amplified in the final output coil I62 to operate the loudspeaker L at requisite volume.

It will now be apparent that I have produced a 2,oae,19o V utilizing'thecomparatively simple apparatus ior circuits of a radio receiver to record broadcast reception without interfering with the normal operation of the receiver through the loudspeaker. The movement of a single flnger piece is enough to place the apparatus in condition for recording the voice of any person who speaks or sings into the telephone transmitter at I86. To reproduce a pre viously made record through the loudspeaker oi the radio receiver, it is only necessary to close the switch member 201. It will be clear to those skilled in the art that the circuit diagrams in Figs. 8 and 9 go together, but I considered it advisable to separate them' so as to prevent confusion in drawing the circuit lines, and also to facilitate a description of theinvention. In theactual machine thefinger piece 204, when moving to either of its recording positions, also closes the switch I33- I31 in 8, so that no separate finger piece I36 is necessary. Also, when the reproducing switch 01 I making of sound records on fllrns. When I use the word tape. in the claims without further .quallfication, I means any flexible ribbon-like member on which sound can be recorded. The speech coil 80 may also be used to operate a recording stylus which cuts a spiral track in a wax ,record, but this method of recording is too complicated for home use. I. do not wish to be understood, however, as excluding the wax-cutting method of recording from the. purview of my invention. It is evident that in the practical" embodiment of my combination' radio-recording-reproducing cabinet, various Izhanges and modifications may be re sorted to without departing from the scope of the i invention asfdeflned in the appended claims. 7

I claim as'iny invention: g 1? Recording mechanism' comprising a magnetic tape mounted to run in altematelyioppesite directions, an electromagnetic device controlledby electric impulses for making a plurality of magnetie record tracks on said tape, means for entomatically reversing the movement of said tapeat the end of a record track, and means iorfshifting said device laterally of the tape when the latter is reversed. 1 n

2. 'An electromagnetic recording reproducingdevice comprising a magnetic tape supported for movement in either direction, 'a' pair of stationary non-magnetic plates spaced to receive said tape in a snug fit, and an electromagnetic de- I vice having a pair of pole pieces in axial align-. ment and arranged to touch the outer faces of said plates, whereby the movingjtape is alwa s at the same distance from the adjacent faces 01' said pole.

pieces. g 3. Anelectromag etic recording and reproducing device comprising a magnetic tape supported for movement in either direction, a pair 01' stationary nonmagnetic plates spaced to receive said tapein a snug fit, an electromagnetic device having a pair of pole piecesin axial alignment and arranged to touch the outer faces 01' said plates,

whereby the moving tape is always at the same distance from the adjacent faces of said pole pieces, and means for moving said pole pieces laterally of said plates.

4. The combination of a radio receiver having an input circuit and two independent output cirsuits, a loudspeaker connected to one of said output circuits, recording mechanism connected to the other output circuit, said mechanism including a telephone transmitter adapted to be connected to said input circuit, switch means for closing both of said output circuits to record broadcast reception while it is reproduced through said loudspeaker, and switch means for closing only said other output circuit to operate said recording mechanism through said transmitter while the radio receiver and loudspeaker are incapable of broadcast reception.

5. A radio-phonograph cabinet containing a radio receiver and a loudspeaker, phonographic recording and reproducing mechanism in said cabinet comprising a flexible tape for receiving a plurality of record tracks which run in alternately opposite directions, said recording mechanism including a telephone transmitter connected by wire to the cabinet, means for operating said tape simultaneously with.the radio receiver to record broadcast reception, and means for operatively connecting said transmitter and tape to record the sound waves actuating said transmitter while the receiver is inoperative, the amplifying system of said receiver being used in both of said recording operations and in the reproducing operation of said phonographic mechanism.

6. The combination of a radio receiver having an audio frequency amplifying system inclusive of input and output circuits, a recording and reproducing device common to both circuits, said devicehaving an operatingcoil, a loudspeaker adapted for connection with the output circuit, means for connecting said coil with the input circuit to record broadcast reception without interfering with the usual operation of said loudspeaker, a transmitter adapted for direct connection with the input circuit as distinguished from locating

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