US2429703A - Magnetic recording device - Google Patents

Description

Oct. 28,' 1947. H.A. vAGTBoRG ITAL 2,429,703

l MAGNETIC RECORDING DEVICE Raymond err/1er'v by n E;

Oct. 28, 1947. H. A. vAGTBoRG E1' Al. 2,429,703

MAGNETIC R'acomami` DEVICE Filed Dec. 26, 1942 2 Sheets-Sheet 2 Patented Oct. 28, 19247 MAGNETIC RECORDING DEVICE Harold A. Vagtborg and Marvin Cami-as, Chicago,

and Raymond E. Zenner, Brookfield, Ill., assignors to Armour Research Foundatiomchicago, Ill., a corporation oi.' Illinois Application December 26, 1942, Serial No. 470,208

- s claims. 1

This invention relates to improvements in a magnetic recording device, wherein a sound recording, such for example as the human voice, may be made by magnetizing an elongated traveling recording medium in the form of a paramagnetic tape, paramagnetic wire, or the equivalent.

We are aware that in the past many and various types of magnetic recording devices have been developed,land in these devices a magnetic recording is made by successively magnetizing increments of the traveling recording medium. However, insofar as we are aware, not any of these previously known devices have been both portable to an ultimate degree and wholly selfenergizing, that is, having embodied therein everything necessary for satisfactory and eilicient operation.

Under certain circumstances and conditions it is highly desirable to have a magnetic recorder which requires no outside connections of any kind, and which is sumciently portable to be carried in a pocket or knapsack on the person so as to be available for instant usage regardless of the locality of the bearer. A device of such character would be extremely convenient for use by a military ofcer or other person on inspection duty whereby comments, orders, suggestions, information, etc. would be immediately dictated by such oflicer or person for later reproduction and transcription. Such a device would also be extremely convenient for recogniranceA duty, enabling the recognizance man to directly dictate reports at the instant he makes observation, and for many other military and civilian duties, providing a record of events or observations which is substantially indestructable unless intentionally ruined, and which, if lost, is of little value to the nder unless the nder has adequate apparatus to reproduce the recording.

With the foregoing in mind, it is an important object of the instant invention to provide a selfsufcient magnetic recording device which is of such small size as to be carried within a pocket of the user, and which requires no outside connections or other apparatus in order to operate conveniently and eflciently.

Another object of the invention is the provision of a compact magnetic recording device which embodies its own power supply and which willv perform eiliciently Without the aid of any connections to outside apparatus.

It is also an object of this invention to provide a magnetic recording device especially arranged to handle a scramble-wound recording medium,

2 eliminating the necessity of rewinding such scramble-wound medium before it is used in connection with the present invention.

Also a feature of the invention resides in the provision of a magnetic recording device having guide means to provide for the very facile insertion of the recording medium in position to have a record placed thereon by way of magnetlzation.

Another feature of the invention resides in the provision of a light weight compact, highly portable magnetic recording device equipped with means not only for the purpose of magnetizing the traveling recording medium in accordance with sound being recorded, but also equipped with. means to condition such medium prior to a new recording being placed thereon, thus eliminating the necessity of a separate operation to demagnetize and rewind a recording medium before it is used again on the instant recording device.

Still another object ofthe invention resides in the provision of a highly portable, light weight magnetic recording device arranged for one hand support and operation during its use.

A further object of the invention resides in the provision of a. highly compact readily portable magnetic recording device including its own permanently attached sound pick-up element, eliminating the necessity of the operator carrying any additional or spare parts for the device, with the possible exception of an extra spool of recording medium in the event a longer than usual recording is contemplated.

Still a, further object of the instant invention is the provision of a highly portable and compact magnetic recording device which is selfsuiiicient, even to the extent of having its own speed control, means to prevent over-run of the supply spool of the recording medium, and provided With simple stop mechanism to control the operation of the device.

It is also an object of this invention to provide a highly portable, compact and self-suillcient magnetic recording device wherein a recording is made by successively magnetizing a traveling recording medium, the device being equipped with a spring motor forvoperating the mechanism to move the recording medium.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a vertical sectional view taken through the front part of the casing of a. magnetic recording device embodying principles of the instant invention, illustrating salient parts of the device in elevation.

Figure 2 is a vertical sectional vview taken through the rear portion of the casing of the recording device seen in Figure 1, illustrating salient parts of the device in elevation.

Figure 3 is plan sectional view of the device of Figures 1 and 2, taken substantially as indicated by the section line III-III of Figure l, looking in the direction of the arrows;

Figure 4 is a transverse vertical sectional view taken substantially as indicated by the staggered line IV-IV of Figure 3, with certain parts shown in elevation for clarity;

Figure 5 is a fragmentary enlargement of the structure seen in the lower central portion of Figure 3, with the guiding means for the insertion of the recording medium removed; l

Figure 6 is a front elevational viewy of the structure seen in Figure 5; and

Figure 7 is a simplified schematic diagram showing a satisfactory electrical hook-up for the instant invention.

As shown on the drawings:

In Figures 1 to 6 of the drawings, the mechanical features of the illustrated embodiment of this invention are shown, the electrical connections being omitted, as well as certain parts of apparatus embodied in the electrical hook-up such as a battery, transformer, etc. It will be understood that the electrical connections as well as such apparatus as may be embodied exclusively in the electrical circuit are disposed within the 35 casing containing the mechanical parts illustrated in Figures 1 to 6 inclusive in any suitable location not occupied by other apparatus. 'I'he salient elements of the electrical circuit are indicated in simplified schematic form in Figure 'Z 40 4 mounted on a suitable stub shaft, which engages the partition 3, for free rotation.

, Near the opposite end of the panel 3 is a similar reel or spool I2 which functions as a pickup or receiving reel upon which the recording medium is wound after it has been magnetized in accordance with the particular sounds to be recorded. During its travel from the spool I0 to the spool I2, the recording medium II -`may be both cleaned and magnetized again in accordance with a newly desired sound record. After the recording medium has been wound on the spool I2, it is a simple expedient to remove this spool, place the spool I0 in the position of -spool I2, and insert a new supply spool in the position formerly occupied by spool l0.

The spool I2 is a driven spool and is mounted on the end of a driven shaft I3 extending through the partition 3. This shaft carries a gear I 4 in the rear compartment 'of the casing which is enmeshed with a considerably larger gear I5 fixed to a rotatable spring housing I6 floating on a shaft I'I. As best seen in Figure 2, a flat spring I8 is coiled within the housing I6, one end of the spring being anchored to the housing I3 as indicated at I9, and the other end of the spring being anchored to the shaft I1 as indicated at 20.

'I'he shaft I1 extends rearwardly to a vertically so disposed support 2l carried by the partition 3 the size of the bottom, and an inner channel 60 shaped partition 3 xedly attached to both the top and the bottom. End walls l, and 5 of substantially the same width as the top 2 may be integral or attached to the bottom I and top 2 to form a box-like construction closed on one side by the partition 3 and on the other side by a back cover 6 pivoted to the bottom as indicated at 1. On the opposite side of the partition 3, the complete closure is made by a box-like front cover 3 pivoted as indicated at 9 on the bottom member I. It is therefore apparent that when the cover 3 and back panel 6 are swung downwardly, all of the apparatus contained within the casing on both sides of the partition 3 is readily available for attention. Any suitable form of latching or locking means may be used to hold the back and front covers of the casing in closed position.

Mounted on the partition 3 near one end thereof and inside the front compartment of the casing is a reel or spool lli which functions as a supply spool, carrying a supply of recording medium which in the illustrated instance is in the form of a fine round wire Il.

o at 3|.

with the aid of a plurality of bolt and spacer sleeve connections 22, as seen clearly in Figure 3. On the rear side of the support 2i the shaft I1 has a ratchet wheel 23 keyed thereto. This ratchet wheel is engaged by a bell crank pawl 2l pivoted as indicated at to the support 2|, and maintained in engagement with the ratchet wheel by a tension spring 26, as clearly seen in Figure 2. Thus, the shaft Il is prevented from turning by action of the spring I8, and when the spring is wound, the opposite end of the spring namely, the point of attachment` I9 with the spring housing, is the only one free to move, and so the spring housing, together with the gear I5, is rotated as the spring tends to unwind. With reference again to Figure 2, it will be seen that the exposed end of the shaft l1 is provided with a diametral rib 21 and, as seen best in Figure 3, a key 28 having a complemental end configuration may be inserted through an aperture in the back panel 3 into engagement with the shaft II for winding up the spring.

Of course, rotation of the spring housing I6 together with the gear I5 causes rotation in the opposite direction of the gear I4 and likewise the shaft I 3 carrying the take-up spool I2. To maintain substantially constant speed of the spool I2 during operation, the rearwardly extending end of the shaft is provided with a suitable governing arrangement generally indicated by numeral 29 in Figure 3 which may be in the form of a friction brake or any equivalent structure, details of which are not necessary to illlustrate herein.

The start and stop control for the magnetic recording device is best seen in Figures 2 and 3. With reference to these figures it will be noted that a lever 30 projects through a suitable opening in the end wall E of the casing, and this lever is pivoted to the aforesaid partition 3 as indicated The inner end of the lever is shaped for engagement between adjacent teeth of the gear I4 as indicated at 32 in Figure 2, so that when such engagement is established, the lever effectively prevents rotation of the gear Il and like- This reel I0 is 75 wise the gear I5 and spring housing I3. In order `which the lever extends. A simple flick of the finger or thumb will then release the lever from the notch, and the spring 33 will return the inner end 32 of the lever into engagement with the gear I4 and not only stop but hold the device in stop position. If desired, a suitable switch for energizing the electrical circuit embodied in the invention may be incorporated with this lever, so that the switch will be closed when the leveris moved to running position, and the switch will automatically -be opened when the lever is moved tostop position,

In view of the fact that a sudden stopping of operation may permit a slight over-run or coasting of the supply spool III so as to provide some slack in the wire immediately following the cessation of operation, a leaf spring 35 is mounted on the inner partition 3 in a manner to constantly bear against the inner side surface of the spool I 3, as seen clearly in Figure 3, to thereby provide suiiicient braking action to prevent over-run or coasting of the spool I0, but not suilicient braking action to interfere with normal operation of the device.

Now with reference to Figures 5 and 6, it will be seen that the wire II in traveling from the reel III to the reel I2 ilrst passes between a horizontally disposed pulley 36 and a horizontally disposed pulley 31, then through the upper portion of a magnetic recording head 38, and over a vertically disposed pulley 33 to the reel I2. The pulleys 36 and 31 are staggered with respect to the desired path of travel of the wire II. but it will be noted with reference to Figure 5 that the bottoms of the grooves in these two pulleys are in alignment with a groove 40 in the magnetic recording head 38 through which groove the wire must pass. This groove 40 is also in direct alignment with the upper point in the bottom of the groove of the vertically disposed pulley 39. Consequently, if the spool I0 contains a supply of scramble-wound wire, that is, wire that was wound haphazardly upon the spool with little or no level winding attempt, the pulleys 36 and 31 will line up such scramble-wound wire so that it will pass directly through the groove in the recording head, over the pulley 33, and evenly onto the reel I2.

To insure a level wind of the wire II on the reel I2, a mechanism is provided which includes a plate 4I pivoted at 42 to the horizontal face of an L-shape bracket 43 attached to the inner partition 3 of the casing. The plate 4I supports the pulleys 36 and 31, the magnetizing or recording head 38, and the pulley 33, so that all of these pulleys and the recording head must move backwardly and forwardly with the swing of the plate 4I. With reference more particularly to Figures 3 and 5, it will be seen that a cam riding projection 44 extends laterally from the plate 4I through an opening 45 in the partition 3 into contact with the surface of a cam 48 carried by the aforesaid spring housing I6 and gear I5. The cam 46 is provided with such a surface vthat the plate 4I will be pivoted around the point 42 backwardly and forwardly during turning of the gear I5.

Thus, due to the pivotal movement of the plate 4 I, together with the various pulleys and recording head carried by this plate, the wire is accurately level wound upon the spool or reel I2. On the opposite side of the plate 4I from the cam rider 44, this plate is provided with another projection or lug 41, and a similar lug 48 extends from the iixed'bracket 43. Between these lugs, a tension spring 43 is disposed so as to hold the plate 4I in operative connection with the cam 46. All of the pulleys 36, 31 and 33 are idler pulleys and rotate by the friction of the wire thereagalnst.

Means are also provided to insure or facilitate a ready and easy threading of the recording medium into its proper position when a new supply roll I0 is placed upon the device. It would be an extremely difllcult operation to thread the end of a wire between the pulleys 36 and-31, into the groove 40 of the `recording head, and over the pulley 33, and then maintain that wire in proper position while the end of the wire was anchored to the receiving spool `I2. To obviate any such difficulty, yet accomplish the same purpose in a very facile manner, the wire is first taken from the spool AIIl and attached directly to the spool I2. 'I'hen the spool I0 is rotated slightly to provide some slack in the wire between the two spools. This slack portion of the wire is then pushed through an open bottomed groove 50 in a guiding member 5I which is secured to the mov- `able plate 4I by bolts 52 or in any otherl equivalent manner. As seen best in Figure 4, the guide 5I is in the shape of an inverted channel, and the groove 53 is formed in the nature of a superstructure extending upwardly from the bottom of the channel. In that portion of the guide member that passes directly over the recording head 38, it will be seen that the groove 5I! of the guide member is spaced directly over and parallels the groove 40 in the recording head. With reference to Figure 3, it will also be seen that the groove 50 in the guide member curves in keeping with the staggered pulleys 36 and 31 .as indicated at 53, so that the groove of the guide member is disposed in such a manner that a wire pushed therethrough will pass by the flange on each of these pulleys.

When the wire II is threaded through the groove in the guide member 5I, past the flanges on the pulleys 36 and 31, into the groove 40 of the recording head 38, and into the groove of the vertically disposed pulley 33, the reel I0 is then preferably turned backward suiliciently to take up the slack in the wire, and the wire will then seat within the grooves of the pulleys 36 and 31, properly seat within the groove 40 in the recording head, and ride the groove of the pulley 33. It is an extremely simple expedient to push the slack portion of the wire through the groove 50 in the guide member 5I and an expedient that may be accomplished with a minimum of time and effort.

In order to make this device quite self-sufficient, amicrophone structure is preferably built on the back wall of the device as indicated at 54, so that all that is necessary for the operator to do is to talk directly into the part 54 when making a recording on the wire I I.

In Figure '1 we have illustrated a simplified form of wiring diagram showing an electrical circuit satisfactory for use with the instant invention. In this diagram, the aforesaid microphone or other pick-up device 54 is connected at one side to a battery 55 and to a ground 56. The other side of the microphone is connected through a conductor l1 to the primary coil of a transformer 7 58. The other side of the battery is connected by way of conductor '9 to both the primary and secondary coils of the transformer 58. The opposite end of the secondary coil is connected through conductor 80 to a magnetizing coil 6I in the recording head 38, and the other end of the magnetizlng coil is grounded as indicated at 82. The recording head 38 in general comprises a core which is preferably laminated, and the coil 6I is disposed around one leg of this core. The upper leg of the core is provided with the groove 48 through which the recording medium travels, and this leg is divided transversely by a relatively narrow air gap so as .to provide confronting pole faces of opposite polarity. It is over the region of this air gap that the recording medium receives its successive magnetizations during the making of a recording on the wire.

may be supplied by a single battery, and this battery as well as the transformer and the necessary wiring may all be contained Within the casing in locations not occupied by other apparatus, the

partition 3 being apertured to provide passage,

way for the wiring wherever necessary. Preferably, the battery may be located in the space beneath the bracket 43 in the front compartment of the casing where it is readily accessible for removal and replacing. It will be apparent from the description and showing of the circuit that sound introduced through the microphone 54 will cause a variation in intensityof the current passing through the magnetizing coil 6|, and thus the recording medium Il will be variably magnetized in keeping with the variations of the sound being recorded. In order to render the device capable of cleaning a wire having a previous recording thereon, a permanent magnet 63 may be disposed adjacent the path of the wire H in front of the recording head 38. It is not necessary that the end of the permanent magnet actually contact the wire, but only that the magnet be in close proximity to the traveling wire. The action of such magnet upon the wire is suiiicient to magnetically saturate the wire and thus wipe out any previous recording on the Wire so that the wire will be clean or without a recording when it reaches the recording head 38. In some instances, especially with simpliiied circuits, it is desirable to employ the magnet B3 to condition a totally demagnetized wire for recording purposes by magnetically saturating the wire. This permanent magnet 63 may be disposed in any suitable location along the path of the` wire in advance of the recording head 38, such for example as being mounted upon the swingable plate 4I in position adjacent the wire as the wire passes the pulley 3l.

In operation, the present invention is extremely simple. Assuming that the spring I8 has been wound by the key 28, it is only necessary for the operator to hold the device easily in one hand, and with a nger or .the thumb flick the starting lever 30 into running position and speak into the microphone 54. At the end of the speaking, it is a simple expedient to ick the lever into stop position, and replace the entire device in a pocket, knapsack, or the like. .The only operation on the part of the operator necessary is periodically winding the spring, starting and stopping the device by the manipulation of the lever 30, and possibly replacing a supply spool of recording medium and now and then a battery, if such work is not done for the operator at his base. It will be appreciated that the recording may be continuous because the spring may be wound during operation.

From the foregoing, it is apparent that we have provided a highly compact and self-sunlcient recording device, which is not only pocket size, carries its own power, is enabled to handle scramble-wound wire, but is also capable of reconditioning a wire or other recording medium prior to its new magnetization in accordance with the new recording. It will also be apparent that the device is designed for one hand operation, is equipped with a speed control, an over-run preventing mechanism, adequate starting and stopping means, and the microphone may be built into a part of the casing. Consequently, there is no necessity for the operator to connect the device with any outside source o! power, and it will be at once noted that the device is economical in construction and use.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

We claim as our invention:

1. A portable magnetic recording device, including a pair of spools from one to the other of which a recording medium is wound, means for magnetizing the traveling medium, a spring motor to drive the receiving spool, a casing containing all said structure, and sound pick-up means in said casing in circuit connection with said magnetizing means.

2. In a magnetic recording device, a pair of spools from one to the other of which a recording medium is wound, driving means to actuate the receiving spool, a pivotal member adjacent the path of the medium between said spools, straightening means for scramble-wound medium carried by said member, magnetizing means carried by said member, cam means associated with said driving means to swing said member back and forth to level-wind the medium on the receiving spool, and guide means also carried by said member to facilitate threading of recording medium into said straightening means and said recording means, said guide means being in the form of a cover member having a bottomless groove shaped in keeping with the path of the medium.

3. In a magnetic recording device, a pair of spools from one to the other of which a recording medium travels a'predetermined path, and straightening means between said spools to direct scramble-wound medium on the supply spool along said predetermined path to the receiving spool, said straightening means being in the form of staggered pulleys.

4. A self-contained and portable magnetic recording device, including a pair of reels from one to the other of which a recording medium is wound, magnetizing means to act on said medium, spring drive means for one of said reels, an impulse pick-up element in circuit connection with said magnetizing means, a source of electrical energy for the circuit including the pick-up element and magnetizing means, and a pocketsize casing containing all the aforesaid structure.

5. A self-contained and portable magnetic recording device, including a casing, a pair of reels in said casing, a recording medium on said reels,

spools from one to the other of which a recording l0 medium is wound, driving means to actuate the receiving spool, a pivotal member adjacent the path of the medium between the spools, staggered pulleys mounted on said pivotal member to straighten scramble-wound medium, magnetizing means carried by said member, and means as-` sociated with said driving means to swing said member back and forth to level-wind the medium on the supply spool.

HAROLD A. VAGTBORG. MARVIN CAMCRAS. RAYMOND lE, ZENNER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name 4 Date 898,283 Stuart Sept. 8, 1908 1,123,147 Sherman Dec. 29, 1914 1,191,182 Heymen July 18, 1916 1,886,856 Warwick Nov. 8, 1932 2,078,357 Woodmansee Apr. 27, 1937

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