US2078357A - Telegraphone apparatus and circuit - Google Patents

Description

April 27,193'@.- at WOODMANSE Em 2,078,357

TELEGRAPHONE APPARATUS AND CIRCUIT Filed Nov. 25, 19:53 4 Sheets-Sh eet 1' z/ a ll 0 4 1% "QI I Inventors v duomeyg April 27, 1937. GI'c. wo65MANsEE ET AL 2,078,357

TELEGRAPHONE APPARATUS AND CIRCUIT Filed Nov. 25, 1953 4 Sheets-Sheet 2 /z I y 7} I A ril 27, 1937. G. c. WOODMANSEE El AL w 9 v TELEGRAPHONE APPARATUS AND GiRcUIT File d Nov. 25, 1955 4 sheets sheet 4 Inventors Patented Apr. 27, 1937 UNITED STATES PATENT OFFICE.

$07135! TEIEGBAPHONE APPARATUS AND CIRCUIT Application November 25, 1933, Serial No. 099,792

- 19 Claims.

This invention relates to telegraphone devices for recording sound magnetically on a steel wire tively aligning the pole pieces with each other and with the recording and reproducing wire in a telegraphone.

Another object isto provide a simple and effective telegraphone mechanism for maintaining the steel recording wire taut at all times.

Another object is to provide a simple and effective mechanism for reversing the direction of movement of the recording wire in a telegraphone.

Still another object is to provide means on a telegraphone for visually indicating the point longitudinally on the recording wire which is passing through the recording and reproducing head.

The foregoing, together with other minor objects and features of the invention will be apparent from the following detailed description which refers to the drawings:

In the drawings:

Fig. 1 is a plan view of a telegraphone in accordance with theinvention;

Fig. 2 is a front elevation view of the telegraphone with a portion of the base cut away to show'the head-supporting standard;

Fig. 3 is an end view of the telegraphone partly in section showing the driving motor and the head-oscillating mechanism;

Fig. 4 is a detail view or a portion of the under side oi the machine showing the driving mechanism for the wire gauge;

'Fig. 5 is a detail view at right angles to th view shown in Fig. 4 taken in the plane V-V of Fig. 4; v

Fig. 6 is a cross section through the clutch for connecting the driving motor to the wire windingspools;

Fig. '7 is a longitudinal section through the clutch in the plane VII-VII of Fig. 6;

Fig. 8 is a detail section view of a portion. of the which are supported a winding spool clutch mechanism taken in the curved plane VIIIVIII of Fig. 6;

Fig. 9 is a cross sectionthrough the head and supporting standard taken in the plane IX-IX of Fig. 2; p I

Fig. 10 is a detail section'through the recording and reproducing head taken in the plane x-x of Fig. 9;

Fig; 11 is a horizontal section through the recording and reproducing head taken in the plane 31-!!! of Fig. 2; t

Fig. 12 is a schematic diagram of an erasing and recording circuit foruse with out telegraphone.

Fig. 13 is a schematic diagram of a reproducing circuit for use with our telegraphone;

Fig. 14 is a detail cross section showing a modifled recording and reproducing headconstruction in which the pole piece is rigidly mounted in the coil and the coil is supported in rubber;

Fig. 15 is a detail cross section of a coil and pole piece construction in which the pole piece is supported in rubber within the coil;

Fig. 16 is a detail cross section showing still another method of supporting the coil and core piece, in which the core piece is rigidly mounted within the coil and the coil is slidably mounted in the head;

Fig. 1'? is a detail cross section of a coil and core piece construction in which the coil is rigidly mounted in the head and the core piece is slid-' .ably mounted in the coil and resiliently urged toward the wire;

Fig. 18 is a detail crosssection showing a coil Fig. 21 is a detail view showing core piecesof a particular shape and dimensions relative to the recording wire;

Fig. 22 is a detail view of a core piece having a hardened tip;

Fig. 23 is'a greatly enlart'ed detail cross section of a core construction in which the juxtaposed core pieces are held in alignment by interlocking sliding guides on. the respective pole pieces; and Fig. 24 is a plan view oi'the structure shown in section in Fig. 23.-

Referring to Fig. 1 of the drawings, our telegraphone apparatus comprises a base I, upon 2, a feed supported in bearing members 3 and 9, and I and II, respectively, which are supported from the base i by suitable standards. The spools 2 and 3 may beattached to their supporting shafts 3 and 1, respectively, in any suitable mannerbut it has been found convenient to provide hubs on the shafts over which the spools flt andare retained in position by means of lock nuts l2, as

shown in Fig. 2. Thus, in Fig. 3 the spool 2 is removed from shaft 5 disclosing the hub 6a, this hub being provided with a pin 6b which engages with a cooperating recess on thespool 2 to prevent relative rotation between the hub and spool when the spool is attached.

During actual recordation or reproduction of sound on or from the recordiwire 5 the latter is unwound from the feed spool 3 onto the winding spool 2, and this movement is accomplished by applying rotating power to the shaft 5 through a pulley l3 keyedthereto and a belt 14 from a pulley I5 which is adapted to be connected in driving relation with a drive pulley it which is rotated through a belt I! from a pulley l8 on an electric motor l9, which motor is mounted on the under side of the'base I, as shown in Fig. 3.

Following the recordation or reproduction of sound by unwinding the wire 5 from the feed spool 3 to the winding spool 2, the wire must be rewound onto spool 3. This rewinding is accomplished by applying power to spool 3 through shaft 1, the shaft 1 under these conditions being connected in driving relation with the pulley I3 and the latter run in the opposite direction by reversing the electric motor I9. To apply the power of the motor automatically, either to the shaft 6 or the shaft 1, we provide an automatic rotatably mounted upon a bearing sleeve or bushing 20 which is rigidly secured to the supporting standard 2|, and surrounds the shaft 1,

the shaft 1 rotating freely withinthe bushing 20. The pulley l5, which is belted to the pulley l3 on shaft 6, is also rotatably mounted uponthe stationary bushing 20.

To establish driving connection between the pulley l6 and the pulley l 5, the latter is provided with a shoulder 22 which extends within an annular recess 23 in the pulley l6, and a clutch mechanism is provided for frictionally connecting this flange22 tothe pulley Hi. This mechanism comprises a hardened liner ring or collar 24 secured to the inner surface of flange 22,- a

" hub 25 rigidly secured to the flange 26 of pulley I6, and a series of balls 21 mounted in races provided in cam grooves 28 (Fig. 6) in the outer peripheral surface of the hub25. The balls 21 are retained in proper relative positions by a retainer 29 which fixes the circumferential position of the balls relative to each other but permits free. radial movementthereof. Each retainer 23 is surrounded by a split spring steel band amass? 33 which tends to retain the balls in the lower ends of the cam grooves 28. When the balls 21 are contracted within the retainer 29 by the band 30, the latter is out of engagement with the collar 24 so'that there is no driving engagement between thehub 25 on pulley l6 and the collar 24 on pulley l5. Under these conditions the balls 21 are located in the deep ends of their associated cam grooves .28.

An exactly similar mechanism to that described ispositioned on the opposite side of the flange 26 for effecting driving engagement between the pulley l6 and a member 3| which is rigidly secured to the shaft 1. Thus the member 3! is provided with an annular shoulder 32 extending into a recess in the pulley l6 and has secured to its inner surface a hardened ring 33. A hub 34 is rigidly secured 'to' the flange 26 opposite the hub 25 and positioned concentrically within the ring 33'. Balls 35 held in position by a retainer 35 are mounted within cam grooves 31 in the hub 34, and a spring steel clip 38 is provided to urge the balls into position within the retainer.

It will be observed from Fig. 6 that rotation of the hub "34- in a counterclockwise direction will cause the balls 35 to ride outwardly in their of the hub 25 in a clockwise direction (relative.

to Fig. 6) tends to force the balls 21 and the clip 30 outward against the ring 24 to lock the hub 25 and flywheel [6 into driving relation with the pulley l5.

To improve the operation of the clutch and make it more positive, the retainers 29 and 36, respectively, on opposite sides of the pulley flange 26 are rigidly connected together by pins 39 (Fig. 8) which extend through recesses 40 provided therefor in the flange 26. This forces .the two retainers to move together but permits them to oscillate sufllciently with respect to the 'hubs 25 and 34 to lock the hub 25 to the ring 24- in one position and lock the hub 34 to the ring 33 in the opposite position.

This mechanism functions as follows: Assume that it is desired to drive the winding spool 2 in clockwise direction (with respect to Fig. 2). To do this the motor I9 is started in a clockwise direction (again with the direction being taken with reference to Fig. 2). This accelerates the pulley IS in a clockwise direction and, since the hub 34 is rigidly attached to the pulley l6, its corresponding movement tends to move the balls intothe deep ends of their cam grooves, there by maintaining the hub 34 out of engagement with the ring 33 and eliminating anydriving connection between the pulley l6 and the shaft 1. The shaft 1 is, therefore, in condition to rotate freely as the wire 5 is unwound from spool 3. As pulley L6 accelerated in a clockwise direction, however, the corresponding rotation of the hub 25 tended to carry the hub ahead of the balls 21 and the retainer 29, thereby forcing the balls 21 rearwardly along their cam grooves against the clip 30 until they forced the clip 30 against and shaft 6.

through the medium of the belt u, pulley n Starting of the motor IS in the opposite direction causes the clutch within pulley l6 to function in exactly the opposite manner to that just described to connect the pulley I6 in driving relation with the shaftl and break connection between pulley l5 and pulley IS. The direction in which the motor I9 is driven is controlled by varying the electrical connections (not shown 'in the drawings) thereto in any known manner scribed and it has been found that this spring makes the clutch connection positive and at the same time causes the clutch to engage smoothly, thereby preventing any jerk or shock tothedriving mechanism. v

-It is very important in a telegraphone that the steel wire be maintained taut between the feed and wind up spools at all times because the wire is of very hard steel and if it becomes slack it frequentlybreaks when the slack is taken up. Breakage of the wire has been a common defect of prior telegraphones and it is very important that the main cause of breakage, namely, slackening of the wire, be prevented insofar as p05 sible. slackening of the wire most frequently occurs when a machine is stopped before much wire has been unwound from the feeding spool. This is for the reason that the total weight of the wire is considerable and, if most of the wire is on the feeding spool at the time the machine is stopped, the weight of the wire causes the feeding spool to have a greater moment of inertia than the winding spool. Therefore, when the power is removed from the winding spool it tends to stop more quickly than the feeding spool, with the result that wire continues to unwind from the feeding spool after the windi spool has stopped. We prevent continued motion of the feeding spool after stoppage of the winding spool by so designing the driving mech-.

anism that the total moment of inertia of the driving mechanism is at all times greater than the moment of inertia of the feeding mechanism regardless of the relative amount of wire on the feeding and winding spools. The means for accomplishing this result is a flywheel 42 of substantial size mounted on the shaft of the motor is (Fig. 3) mounted upon thepulley IE but we prefer to mount it on the motor shaft as in that position it directly controls the acceleration and deceleration of the motor and is more or less resiliently coupled to the pulley I6 by the belt IL The flywheel 42 is so proportioned-relative to the weights of the spools and wire thereon that the moment of inertia of the driving system is always greater than the moment of inertia of the feeding spool regardless of the amount of wire on the latter. This flywheel functions during both the winding and rewinding operations since it is always connected to the spool that is pulling the wire, whether the wire is being wound from the feed spool 3 onto the winding spool 2 or being rewound from the winding spool 2 onto the feed spool 3. 1 a

It will be observed from Fig. 1 that the wire 5' passes through the head 4 in transit from one This flywheel, if desired, may be spool to the other. The smooth winding of the wire onto which every spool is taking up the wire is accomplished by oscillating the head 4 forwardly and rearwardly by means of a cam mechanism. This cam mechanism comprises a heartshaped cam 43 (Fig. 3) mounted upon a shaft 44 (Fig. 4) journaled in bearings 45 and 46 which are supported from the under side of the base plate I. follower 41 (Fig. 3) mounted on a lever 43 which Cooperatingwith the cam 43 is a cam is secured to a hub 49 journaled for oscillatory movement in a bearing member 50 attached to the under side of the base plate I. The head 4 is mounted upon a vertical standard H which is also rigidly attached at its lower end to the hub 43. It will be observed, therefore, that rotation of the cam 43 oscillates the lever 48 and hub supporting standard 5| through an arc to shift the head 4 back and forth between the flanges-and the spools 2 and 3 to distribute the wire on the winding spool. The cam 43 is rotated by means of a beveled gear 52 keyed to the shaft 44, which beveled gear is driven by a beveled pinion 53 Qfiounted on a vertical shaft 54, to the upper end i which there is keyed a worm wheel 55 which meshes with a worm 56 on the shaft 6.

When power is applied to either spool 2 or 3 to pull the wire from the other spool, the feeding spool (which as referred to here may be either spool 3 or spool 2) sometimes tends to run unevenly or hunt, which is objectionable in that it tends to alternately slacken anti tighten the wire between the two spools. To produce even motion and prevent hunting, 'a friction brake is provided on each spool-supporting drum. Thus, referring to Fig. 3, which discloses the-brake on the drum 6a which supports the spool 2, a disc I50 is secured to the drum 6a against which a brake shoe I5I bears. This brake'shoe I5I is preferably of some resilient material, such 'as felt, and'is mounted on the end of a plunger I52 slidably supported in ferent messagesrecorded at different points along the wire, it is often desired to reproduce a particular message. Heretofore it has only been possible to pick up the message by running the machine and listeningto the undesired messageuntil the desired message was reached. In accordance with the present invention, we provide a counter 51 geared to the wire driving mechanism, which counter indicates visually at all times what portion of the wire 5 is passing through the head 4.,

This counter may be of any conventional construction and is shown connected to the spooldriving mechanism by a shaft 58 (Fig. 4) which is connected by a pinion 59 at one end to the beveled gear 52 and. is connected by beveled gears 60 at the other end to the driving shaft of the counter 51. The counter 51 may be calibrated to indicate I approximately the number of feet of wire that have been run off from one spool to the other or it may 'merely have an arbitrary calibration. It is employed' in the following manner: Assume that a number of different messages are recorded at successive points along the wire 5. At the begin-- ning of each recordation the reading of the counter ii will be noted. Thereafter by rewinding the I machine until'the counter again indicates this the shaft. The frame member 60 is oscillatably mounted on the stub shaft 62 to permit oscillasame reading the operator knows that the wire is in position to reproduce the desired recording.

The head 4, referring to Figs. 9, 10 and 11, comprises a rear frame member 60 and a front frame member 6| each of substantial cylindrical shape and constructed of non-magnetic material, such as aluminum or brass. The rear frame member. 60 is rotatably supported upon a stub shaft 62 which is rigidly attached by an arm 63 to the upper end of the standard 5i. As shown in Fig. 11, the stub shaft 62 is provided with a flange or shoulder 64a on its forward end to prevent forward movement of the frame member 60 off tion of the head and maintain it in alignment with the wire 5 as the feeding spool is emptied and the winding spool fills up. The front frame member 6! is hingedly attached to the rear frame member 60 by a hinge pin 64 passing through the lower end of .frame member BI and through a pair of arms 65 extending forwardly from the lower edge of the rear frame member 60. The frame members and 6| are normally maintained in closed position, as shown in Fig. 9. by a coil spring 66 surrounding the hinge pin 64. Each frame member 60 and 6| supports a recording and reproducing coil and an erasing coil, the recording and reproducing coils in the frame membersbeing juxtaposed to each other and the erasing coils likewise being juxtaposed to each other'on opposite sides of the wire 5. As shown in-Fig. 11, the recording and reproducing coils provided with central bores for receiving and supporting soft iron core pieces 69 and I0, respectively, the inner tips of which pole pieces are adapted to bear against opposite sides of the wire 5. The erasing coils are likewise mounted on spools H and 12 in the rear and front frame members 50 and BI, respectively, and are of similar construction to the recording and reproducing coils. As shownin Fig. 11, the front spools 58 and I2 and their core pieces 10 and M are rigidly mounted in the frame whereas the cooperating rear core pieces 69 and 13, respectively, are resiliently forced in contact with the wire 5 by coil springs 15 and 16. Referring for the moment to Fig. 9, it will be observed that the core pieces Ill leads to the recording and reproducing and erasing coils are brought down through the hollow standard 5|, as shown in Fig. 9. The electrical circuits employed will be described later.

To guide the wire 5 with respect to the core pieces 69, 10, 13 and 14, a pair of arms 80 and BI, respectively, are provided on the rear frame member 60,'these arms being provided with horizontal slots 83 extending half way through from the front face, as shown in Figs. 2 and 11. To permit threading of the wire through the head and thereafter lock the wire in the slots 83, a rotatably locking member 84 is provided in the outer end of each arm 80 and 8|, these locking members 84 also having slots 85 therein, which slots may be turned into registration .with the slots 83 to admit the wire and thereafter turned bushing 98 of rubber.

outof registration with the slots, as shown in Fig. 10, to lock the wire in the head.

The general principles of operation of telegraphones are well known. It will sufilce at this point to state that during recordation the wire I passes through the head from left to right, as

shown in Fig. 11, first traversing the erasing core pieces I3 and H which are magnetized to saturate the wire and thereby remove any prior magnetic records thereon. Thereafter the wire continues on past the recording core pieces 69 and III, which are variably magnetized in accordance with voice currents in their surrounding coils and produce a permanent magnetization of the wire accordance with the voicecurrents. To rep%i i e the message recorded on the wire 5, the e rewound back ontothe feed spool 3, both the erasing and recording magnets in the head beingdeenergized during this operation so that the core pieces do not effect the record recorded on the wire. Thereafter the wire is again fed from left to right through the head but this time the erasing coils are deenergized so that they do not effect the magnetic record on the wire. At the same time the recording and reproducing coils on spools 61 and 68 are connected to a telephone or loud speaker through a suitable amplifying device and as the variably magnetized wire passes through the core pieces 69 and 10 it varies the ma etic flux therein and produces corresponding oice currents in the reproducing currents, which currents are amplified and applied to the sound reproducer.

It is desirable in order that the maximum magnetic efiectbe produced in the wire by the recording pole pieces and also that the maximum magnetic effect he produced in the reproducing core pieces by the wire, that the core pieces mak direct contact with the wire. However, it as...

been found impossible to make the wire run absolutely true with respect to the pole pieces so that it has been the practice to mount the pole pieces more or less loosely in their coils and force them into contact with the wire by a spring. The scraping of the wire against the pole pieces has been found to set up more or less vibration in the pole pieces which tends to introduce extraneous noises. Furthermore, vibration of the core piece with respect to its coil tends to vary the fiux cutting the coil. To overcome these difficulties we. have developed a number of modified forms of construction for supporting the core pieces and coils. Thus referring to Fig. 14, we may mount the core piece rigidly.with respect to the coil spool 9| and then resiliently support the spool 9| in a rubber Jacket 92 which ismounted in the supporting frame member 93 of the recording and repro ucing head. Therubber 92, while permittin a certain amount of movement of the spool 9|, tends to damp out the vibration ,of the spool. The

spool may be urged towardthe wire to exert adesired pressure between the core piece and the wire by means of an adjusting screw 94.

A modified form of construction is shown in Fig. 15 in which the spool 95' is slidably mounted in the supporting frame 96 but in which the iron core piece 91 is supported within the spool by a In this modification also the spool may be moved into desired position with respect to the wire by an adjusting screw 99 in the back plate of the head.

Fig. 16 discloses an arrangement in which the iron core piece I 00 is rigidly mounted with respect to the spool IM and the spool is slidably SPOOL In Fig. 1'7 there is illustrated a Construction in which a spool IN is provided with a hollow iron core member I05 rigidly attached thereto within which there is slidably mounted a core piece "16,-

the latter being urged toward the wire by a spring 101 at the rear thereof. A screw 108 permits adjustment ofthe spring tension. In Figs. 18, 19

' and there is illustrated a form of construction in which the core piece is laminated and is fixed to the spool, the spool being itself mountable in the head in the manner disclosed in Fig. 16. 'It will be observed that the center lamination I09 in Fig. 18 projects beyond the other laminations and is the portion which contacts with the wire. This is a desirable form of construction for the reason that it permits a very small tip for contacting with the wire while at the same time reinforcing the tip member mechanically and also reducing the total reluctance of the core piece by increasing the total amount of iron within the coil without introducing serious losses from eddy currents. The shapes of the laminations and their positions are clearly indicated in the cross section of Fig. 20.

In Figs. 14 to 20 pole pieces are shown having wire contacting tip portions of substantially larger lateral dimensions than the diameter of the wire with which they contact. This-construction is desirable since it does not necessitate accurate alignment of the pole pieces with the wire. Ordinarily, however, it is objectionable for the reason that the hard steel wire soon wears a groove in the pole piece, permitting opposite pole pieces to contact each other on each side of the wire, thereby rendering .the device substantially inoperative for the reason that the flux passes directly between opposite pole pieces with out passing through the wire. Heretofore it has been considered necessary to make the entire pole piece of very soft iron in order that it should have low retentivity and permit rapid change of the magnetic flux in response to the voice currents. We have discovered, however, that wear on the pole pieces can be greatly reduced, and

- in fact for practical purposes substantially eliminated, without interfering with the recordation and reproduction of sound, by hardening the tip only of the core piece, as shown in Fig. 22, in which the shaded portion llfla indicates the hardened part of the pole piece, the unshaded portion, which comprises the bulk of the magi netic material in the core piece, being unhardened. We preferably prepare these core pieces by taking a core piece of suitable shape, as shown in Fig. 22; of pure Norway iron and hardening the tip by first heating it in a flame, then dipping it in a carbonizing flux, again heating it, repeating this operation several times, and finally quenchingv the pole piece in oil or other suitable quenching material. I'his treatment has been I found to make the wire-contacting tip of the pole piece even harder than the wire with which it contacts without in any noticeable degree interfering with the quality and volume of sound reproduction. In fact, the reproduction obtained with these pole pieces appears to be actually superior in some instances to the reproducwould function satisfactorily, it has been the practice to stagger the juxtaposed pole pieces longitudinally to prevent contact therebetween as thepole pieces became grooved by the wire. It is undesirable, however, to stagger the pole pieces for the reason that it brings. a greater length of wire into the magnetizing field of the pole pieces at any instant and-necessitates running the wire at extremely high speeds in order to secure satisfactory reproduction of the higher.

voice frequencies. In accordance with the present invention, we may use oppositely positioned pole pieces of the shape shown in Fig. 21, which permits the pole pieces to be of mechanically soft material since the pole tips are straight and of smaller diameter than the wire. This construction permits the pole pieces to be worn away for a substantial distance before they can be grooved by the wire to come in contact with each other.

An obvious defect of the pole piece construction shown in Fig. 21 is that because of the extremely small sizes of the tips of the pole pieces they must be very rigidly supported else they will not remain in juxtaposed position.

To insure positive alignment of the pole pieces of reduced size the construction shown in Figs. 23 and 24 may be employed, in which the opposite pole pieces H0 and III of iron, or other similar' paramagnetic material, are provided with tips H2 and I [3, respectively, of smaller diameter than the recording wire I it but are enclosed and supported in reinforcing members I I5 and I it of nonmagnetic material, such as brass or aluminum. I'he reinforcing member H6 is provided with grooves Ill on its upper and lower sides, respectively, and the reinforcing member H5 is provided with a pair of tongues H8 on its upper and lower sides respectively, which tongues extend into the grooves ill on the reinforcing member I I6, thereby preventing any relative displacement between the pole pieces I I2 and H3 in a vertical direction or in a direction longitudinal of the wire Ill while at the same time permitting movement of pole pieces H2 and H3 toward each other as they are worn away by the wire H4.

It is to be understood that the various pole pieces and coil constructions shown in Figs. 14 to 24, inclusive, may be used for both the erasing and recording and reproducing structures shown in Fig. 11. It is also to be understood that whereas in Fig. 11 the erasing core piece 14 and the recording and'reproducing core piece III are rigidly mounted with respect to the wire 5, these core schematic diagrams of Fig. 12 and Fig. 13, re-' spectively, Fig. 12 showing the recording circuit and Fig. 13 thereproducing circuit.

Referring first to Fig. 12, we have shown the wire 5 moving first between the pole pieces l2li I24 and I25 of therecording coils I23 and 121,

respectively. A pair of'biasing coils I23 and I23 are also shown surrounding the pole pieces I24 and I23, respectively. For purposes of representation, these coils I23 and I23 have beenshown mounted on the rear ends of theirassociated pole pieces but it is to be understood that in the actual construction of the coils the biasing coils will be wound on top of the recording coils.

Abattery I is connected in series with the two erasing coils I22 and I23 and with a current limiting resistor I3I. A condenser I32 may be connected in shunt across the erasing coils I22 and I23 and a condenser I33 may be connected across the current limiting resistor I3I. These condensers I32 and I33 are optional but we have found that better quality of reproduction is obtained by their use.

The battery I30 is also connected in series with the biasing .coils I23 andv I29 through a current limiting resistor I34. The coils I28 and I29 are preferably shuntedby acondenser I35 and the,

resistor I34 by a condenser I33, the use of these condensers improving the quality of reproduction.

The recording windings I23 and I2'I are connected in series through a condenser I33 and a resistor I33 to the output of an amplifier A to the input of which amplifier there is connected a recording microphone I31. We have discovered that the insertion of the resistor I33 and the condenser I33 in the recording coil circuit greatly improves the fidelity of reproduction obtained.

The current limiting resistor I3I in series with the battery I33 and theerasing coils I22 and I23 is so proportioned relative to the coils I22 and I23 and the potential ofvbattery I33 as to generate a constant magnetic flux between the pole pieces m and m, sail! the steel wire 5 as it passes therebetween. This saturation of thewire not only erases any previous magnetic message that may exist on the wire but prepares it for the next recording.

- The resistance I34 in series with the battery I33 and the biasing coils I23 and I23 is of such value relative to the potential of the battery and the constance of the coils I23 and I23, and these coils aresopoledastoproduceinthereproducing corepieces I24 and I23 a constant magnetic flux of such intensity and polarity as to reduce the magnetism in the saturated wire I to a value approximately half way between zero and saturation. 'I henuxgeneratedbythevoicecurrentsinthe recording coils I23 and I21 is superimposed on thisconstantiiux'byc oils I23and I23tov'arythe magnetism of above andl'ielow theccnstant value it would have were no voice currents applied. Although we have not positively established the reason therefor, we have discovered that theuse of theresistor I33, condenser I33 and the condenser I33 contribute greatly to the quality of recordation obtained with the circuit.

lilthoughtheconstantsofthevariouselements inthecincuitofrlg. l2 maybevariedhetwem wide limits, we have obtained excellent results employing a resistor I33 of. 10,000 ohms, a condenser I33of .02 microfarads, recording coik I23 and I21 of ohms impedance, biasing cosh I23 and I23 of -'l0 ohms impedance, condensers I33 and I33 of .25 microfarads, a battery I33 of 4% volts, resistor I34 of 2,000 ohms resistance ing coils I22 and I23 of hmsistancetand.

I32 and I33 0!.23

cient to magnetically saturate output impedance of the amplifier A may be approximately 500 ohms.

. In actual reproduction the same pole pieces and I coils thereon are used as were used for recording.

have reproducing coils I42 and I 43 thereon, which coils are connected in series through a condenser I 44 to the input of an amplifier A, the output of the amplifier being connected to a loud speaker I45. This circuit. is in accordance with conventionalpractice except for the use of the condenser I44 in series with the reproducing coils.

We have discovered that the use of this condenser contributes materially to the quality of reproduction of voice currents obtained.

In the recording and reproducing circuits of Figs. 12 and 13 the amplifier A may be of any conventional design to give sufficient gain to produce the proper volume. Obviously, the input and output impedances of the amplifier should correspond approximately to the impedances of the apparatus connected thereto in accordance with well established practice.

It is to be understood that the embodiments of the invention described herein represent only a few of many possible variations and the invention is to be limited only as set forth in the appended claims.

We claim: 1. In combination, a recording wire of high retentivity, a recording electroma'gnet, means for moving said wire past said electromagnet, a source of voice current to be recorded on said wire, and means for connecting said source to said recording electromagnet, said means including a condenser of substantial reactance at voice frequencies connected in series with said recording electromagnet.

2. In combination, a recording wire of high retentivity, a recording electromagnet, means for moving said wire past said electromagnet, a source of voice current to be recorded on said-wire. and means for connecting said source to said recording' 1 t, said means including a con-' denserandresistanceof ,tialreactanceat with said re- 4. In combination, a..recording wire of high receptivity, an erasing electromagnet and a recording electroma'gnet, means for moving said wire first p'astsaid erasing electromagnet and thereafter past said recording eleetromagnet, a soule of voic'ecurrents to be recorded on said ""9 meanscomprisingacoilonsaidelectromagnet connected to saidsource. means for apdirectcurrenttosaiderasingelectro-- magnettosaturatesaidwireasitismovedpllt said erasing electromagnet. a biasing coil on said recording electromagnet, and means for supplying direct current thereto in such direction and ing coil on said recording electromagnet.

of such intensity as to partially demagnetize said saturated wire as it moves therepast.

5. Apparatus as described in claim 4 inwhich j a by-pass condenser is shunted across said bias- 6. Apparatus as described in claim 4 in which a by-pass condenser is connectedin shunt across said erasing coil.

7. Apparatus for use in .combination with a wire of high magnetic retentivity having a magnetic record impressed thereon, comprising a reproducing electromagnet, means for 'moving said wire past said electromagnet, electrically actuated means connected to said electromagnet for reproducing ,sound corresponding to currents induced in said electromagnet by said wire, and a condenser connected in series with said electromagnet and said sound reproducing means.

8. Apparatus for use in combination with a wire of high magnetic retentivity having a magnetic record impressed thereon, comprising a reproducing electromagnet, means for moving said wire past said electromagnet, electrically actuated means connected. to said electromagnet for reproducing sound corresponding to currents induced in said electromagnet by said wire, and a high pass filter means connected between said electromagnet and said sound reproducing means.

9. In a telegraphone, means for moving and guiding a magnetic record wire through a fixed path, a core piece of paramagnetic material positioned to contact said wire as it moves through said path, coil supporting means rigidly attached to said core, a coil on said coil supporting means, a frame member for supporting said coil supporting means and a rubber sheath between said 'coil supporting means and said frame member for supporting the coil andcore with respect to the frame piece.

10. In a telegraphone, means for moving and guiding a record wire through a fixed path, a core piece of paramagnetic material for cooperating magnetically with said wire, said core piece being positioned in contact with said wire, a coil surrounding said core piece and means for rigidly supporting said coil and core piece with respect to each other, a supporting frame, and means for movably supporting said coil and core supporting means in said frame for movement with said wire in response to transverse vibration of said wire.

11. In a telegraphone, means for moving and guiding a record wire through a fixed path, a core piece adapted to cooperate with said wire, a coil surrounding said core piece in magnetic relation thereto, mean for supporting said coil and means for supporting said core within said coil comprising a rubber sh'eath'between said core piece and coil supporting means.

12. In a telegraphone, means for supporting and guiding a record wire'through a fixed path, a pair of core pieces positioned in juxtaposed relation on opposite sides of said wire, cooperating coils surrounding said core pieces, and means for urging said core pieces against said wireon opposite sides thereof, said core pieces having tip portions for contacting said record wire, which tip portions are of substantially the same transverse dimensions throughout their length and-of smaller dimensions transversely of said record wire than the diameter of said record wire.-

13. In a telegraphone, means for supporting and guiding a record wire through a fixed path, a core'piece positioned to contact with said wire, means for urging said core piece against said wire and a coil surrounding said core piece, said core piece being of paramagnetic material of low retentivity substantially throughout except for the tip portion in'contact with said wire, said tip portion being hardened.

14. In a telegraphone, means for supporting and moving a record wire through a fixed path, a core piece positioned to contact with said wire at one end and a coil surrounding said core piece, said core piece being of material of low magnetic retentivity throughout its major portion but having a hardened steel tip portion in contact with said wire.

15. In a telegraphone, means for guiding and moving a record wire through a fixed path, a pair of juxtaposed core pieces, having coils magnetically associated therewith, positioned to engage said wire on oppositesides thereof, and interlocking guide means on said core pieces for maintaining said core pieces in juxtaposed relation independently of said wire.

16. In a telegraphone, a recording and reproducing head, means for continuously moving a record wire through said head, said head comprising a pair of armspositioned in the path of said wire, slits in said arms for receiving said wire, and rotatable end members on said arms also having slits therein whereby said wire may .be inserted in said slits by rotating said end members to bring their slits into registration with the in the arms, and the wire thereafter locked in osition by rotating the end members to bring their slits out of registration with the slits in the arms.

17. In a telegraphone, a recording and reproducing head, means for moving a record wire through said head comprising a feed spool and a winding spool, reversible motor means for driving said spools, clutch means for automatically connecting said motor means'to said winding spool in response to rotation of said motor in one direction and for connecting said motor to said feed spool to rewind the wire when the motor is operated in the opposite direction, the rotatable system comprising said motor means and either one of said spool means and connecting mechanism having a moment of inertia substantially greater than the moment of inertia of either one of said spools, together with the wire thereon, even when the spool is filled with record'wire.

18. In a telegraphone, a recording and reproducing head, a pair of spools positioned on opposite sides of said recording head for feeding record wire through said recording head from one spool to the other, a reversible motor for driving either one of said spools, and a clutch mechanism for selectively connecting saidmotor to one spool or the other according to the direction' of rotation of the motor, said .clutch means comprising a pair of hub .members in driven relation with the motor means,- one hub member having inclined the other having oppositely inclined cam slots in its periphery, a pair of ring members surrounding said respective hubs, one of said ring members being connected in driving relation to one of said spools and the other being connected in cam slots in its periphery and driving relation to the other of said spools, balls spouse to movement or the'associated balls the shallow ends of said cam slots.

19. In a telegraphone, a recording and reprointo ' ducing head, a pair of spools positioned on 0pposite -sides thereof for feeding wire through said recording head, reversible motor means for,driving said spools, and clutch means for selectively amass! while permitting free radial movement of said balls, a pair of ring members positioned concentrically about said respective retainers and connected respectively to said two spools, the balls in one retainer being adapted to lock the associated hub and ring member together in re-- sponse to relative rotation between said hub and associated retainer in one direction and the balls associated with the other hub being adapted to lock that hub to its associated surrounded ring member in response to relative rotation between that hub and ball retainer in vthe opposite direction, and means for locking said two retainers together.

GEORGE C. WOODMANSEE. CLaY G.- WOODMANSEE.

Images