US901397A - Apparatus for recording and reproducing by the telegraphone principle. - Google Patents

Description

H. R. STUART.

APPARATUS FOR RECORDING AND REPRODUGIN G BY THE TELEGRAPHONE PRINCIPLE.

APPLICATION FILED HABHZ, 1908.

Patented Qct.20,1908.

UNITED STA HARVE R. STUART, OF

APPARATUS FOR Specification of Letters Patent.

Es PATENT OFFICE;

WHEELIN G, WEST VIRGINIA. RECORDING AND REPRODUCIN G BY THE TELEGRAPHON E PRINCIPLE.

Patented Oct. 20, 1908.

Application filed March 2, 1908. Serial N 0. 418,690.

To all whom it may concern:

Be it known that I, HARVE R. STUART, a citizen of the United States, residing at Wheeling, in the county of Ohio and State of \Vest Virginia, have invented certain new and useful Improvements in Apparatus for Recording and Reproducing by the Telegraphone Principle, of Whichthe following is a full, clear, and exact description.

This invention relates to means for recording and reproducing speech, sounds and signals, under the telegraphone principle, and has for its object the provision of means whereby the record can. be strongly impressed upon the recording body so that the reproduction will be correspondingly louder.

According 'to the principle of the telegraphone, the recording magnet is infiuenced by the telephonic currents only, and the strength of the record is therefore dependent upon the comparatively weak magnetism which such currents are capable of developing.

According to the present invention the electro-magnetism which is used to record the message is derived from an independent source which may be either a permanent magnet or an electromagnet, and this independent field 'force is manipulated and directed so as to affect the recording disk, band or body by the mechanical movements of a diaphragm which are created by the voice or signal currents. In this Way the permanent or electro-magnet may be a comparatively strong one, so that the available power for recording purposes is practically unlimited.

My invention is illustrated in the accompanying drawing in which the apparatus is illustrated somewhat conventionally.

Figure 1 is a front elevation of my improved apparatus, the parts being shown in section; Fig. 2 is a si magnet system; Figs. 3 and 4 illustrate modifications of the anism.

The recording body of a telegraphone is illustrated by 1, being for convenience in the form of a steel disk shown in edge View and supported upon a centrally rotated axis 2. Mounted ad acent to the disk are two electromagnet coils 3 and 4, surrounding soft iron cores, which have steel spring extensions 5 and 6, forming arts of the magaetic circuit. The cores 0 the two magnets ire connected by a back yoke 7, from the 1 middle point of de elevation of the other to an adjusting screw 24.

fiu-x controlling mech- 'ing the tension which extends a bar of iron cores, and likewise having extension 9. These steel springs are of substantially the same shape and resiliency and are connected together near their lower ends by a cross bar 10, of non-magnetic material, which holds them in fixed relation to each other.

Between the extremities of the springs 5 and 9 is a soft iron bar or piece 11, having a stem 12 projecting midway therefrom and resting at its extremity upon the face of the recording body 1, the extremity of this piece being reduced so as to cover only a small area of the recording body. Likewise between the extremities of the springs 9 and 6 is a similarly T-shaped soft iron piece, indicated by 13 and 14, the extremity of which is also reduced and rests upon the face of the recording body 1. The two parts 12 and 14 serve as cores of electric coils l5 and 16 respectively, and the entire system of coils 3, 4, 15, 16, springs and cores, are mounted upon a single frame 17, so as to movetogether in a radial or other suitable direction across the face of the disk 1 while the latter is in rotation. This movement of the magnet system may be controlled by a suit able feed screw which may operate in one of the openings 18 or 19 of th a guiding rod in the other, similar to any of the usual telegraphone or phonograph feeding mechanisms.

20 indicates an instrument containing a vibratory diaphragm 21, the center-of which is rigidly connected through link 22 with the rod 10, or some other part of the structure 5, 9, 6, 10, so that the movement of the diaphragm will be communicated to the springs 5, 9, and 6, equally and simultaneously. e opposite side of the springs spring 23, se- 10, and at the By adjustof this spring and the posi tion of the instrument 20, the extremities of the springs 5, 9 and 6 are brought to neutral positions or distances from the ends of the soft iron pieces 11 and 13. That is to say, the air gaps between the spring 6 and the piece 13, betwen 9 and 13, between 9 and 11, and between 5 and 11, are all normally equal.

The instrument 20, as shown in Fig. 1, is merely a casing carrying the diaphragm, and having a mouthpiece into which speech or other sounds are to be directed. In Fig.

8, similar to the a steel spring cured at one end to the rod e frame, and

ioo

' pieces 11 and 13 will now 3, the instrument 20 is an ordinary telephone 14.

receiver having the usual diaphragm which is moved by voice currents coming from adistance over the circuit 25, either from being serviceable for the purposes of the invention.

The two coils 3 and 4 are connected in circuit with a constant source of electricity 26, of considerable power, and the direction of winding, or flow of current through, the coils is such as to establish two independent fields of force, the middle core 8 and spring 9 being common to both and having say an S polarity,whereas the outer cores or springs 5 and 6 each have an N polarity. Thus one magnetic circuit is completed or nearly completed through the cross piece 11, while the other is completed or nearly completed through the cross piece 13, and so long as the gaps between the springs and the cross ieces remain uniform, as described, there will be no tendency of the lines of force in the two fields to take different courses.

In the operation of making a recor of a message or signals, the coils 15 and 16 are not in use. That is to say, they are open circuited, and for this purpose a small switch 27 is used, and placed in the open position shown. Whenthe diaphragm 21 is vibrated by the sound waves entering directly into the instrument 20, shown in Fig. 1, or coming from a distance to the instrument, shown in Fig. 3, the movements thereof are imparted to the springs 5, 9 and 6 uniformly and co incidently, a movement of the diaphragm to the left causing spring 6 to approach piece 13, spring 9 to recede from spring and approach piece 11, and spring 5 to recede from piece 11. induced by the two coils 3 and 4 which be, fore traveled uniformly across the respective be deflected because of the fact that the air gaps instead of being uniform are-now narrower at one end of the iron piece and wider at the other, and lines of force which always take the path of least reluctance, will now travel from the end of spring 6 into the piece 13, thence through the core 14, then through the material of the recording body 1 to the other core 1.2, then through the piece 11, and across the narrow gap to the spring 9, the remainder of the circuit being the same as before. At the same instant, the magnetic circuit of the coil 3 will remain s bstantially the same as before, because no path of less reluctance is afforded. A record of the movement of the diaphragm to the left will therefore be impressed upon the steel body, which will have a strength depending upon the strength of the magnet 4, and the sum of the air gaps between 13 and 6, and 11 and 9, this record being represented by a line of magnetism permanently localized in the body 1 between the ends of the cores 12 and Thus the lines of force When the diaphragm 21 moves in the posite direction, or to the right, spring 6 recedes from 13, spring 9 approaches 13 and recedes from 11, and spring 5 approaches 11. The conditions then being reversed the lines of force from coil 3 are caused to travel from spring 5 to piece 11, core 12, recording body 1, core 14, piece 13, and spring 9, the lines from coil 6 continuing through 13 the same as normally. Thus the mo ement of the diaphragm the body 1 by a polarity opposite to that of the movement to the left, and likewise of an intensity depending upon the strength of the magnet and the sum of the air gaps between 5 and 11 and 9 and 13. Since the magnets 3 and 4 are of constant and equal strength, the strength of the recorded impulses with respect to each other will be due to the differences in air gaps to which their production is due, and this will be determined by the amplitude of the respective vibrations.

With this apparatusthe record of a message will be impressed upon the disk 1 in a series of closely adjacent radial lines each of a length equal to the distance between the extremities of the bars 12 and 14. It will be seen that if the movable springs and the cross pieces constitute a switching device for the fields of force of the two constant magnets 3 and 4, which device is controlled by the diaphragm. In reproducing the record thus made, 'the'bars or pole pieces 12 and 14 are caused to retrace the same to the right is recorded in path on the disk as when the record was I made in accordance with the usual telegraphone method. The record may then be made audible in either of two ways: First, the-coils 15 and 16 may be connected in circuit either with the receiver 28 or with a distant receiver through the circuit wires 29, by means of the switch 27 in which case the magnetic record will create currents in the coils 15 and 16, which will aflect the receiver in circuit ,withthem and thus reproduce the record; or, second, the coils 15 and 16 may be left open-circuited, in which case the successive polarities of the magnetic record will be alternately added to those of the coils 3 and 4, causing the system of springs 5, 9 and 6' to be moved alternately to the right and left by a process the converse of that by which the record was originally made. The diaphragm 21 will therefore be correspondingly vibrated and the record made audible in the instrument 20. If the instrument 20 is substituted by a microphone, as indicated in Fig. 4, the instrument will act as a relay and the sounds reproduced at the more or less distant station may be amplified through the additior of battery in the microphone circuit. By this arrangement of the constant and inde pendent field magnets 3 and 4, a magnetii flux of comparatively large power is avail 901,397 v ,8, vable, and is readily manipulated or utilized lirations of the diaphra .will cause said 35 for the (purpose of making records by means ma eticscircuits to incIiidii/the recording Y of the elicate slprings 5, 9 and 6, or their bofy' substantially as described.- equivalent, whic the voice currents or vi- 3. a telegraphone, thecombination of 5 brations are amply able to-move. The rea recordin body, two magnets ofconstant sult is that the record magnetism willbe force, an means whereby the vibrations 4o stronger and the reproduction thereof comcorresponding to the message --or signal will 1nensurately loud. Furthermore, in this cause said ma particular arrangement of the bars or-pole the rec'ordin E ody. a 10 pieces 12 and 14 impin 'ngupon the record- 4.1 In a te egraphone, the combination of ets toalternately act uponf in body at considerab e distances from each a recording body, two olep eces resting 5 0t er, the lines of force traverse larger areas thereon, two magnets --o constant force, a-

of the recording body aml will absorb cormagnetic switching device aalternately .res ondingly vmore ma et ism-, and this directing the field of force of said me stay 15 without seriously decreasing the capacity of through said pole pieces,and,means w erethe recording bod for it isfound that "the by the impulses corresponding to the mes-' 5o turns of the slim pathtraced by the magsage or signal will actu te said magnetic nets upon the face of the disk can overlap switching evice. v v without interference so long as therecord 5. In a telegraphone, means-for reproduc},

of one turn is not exactly superposed upon 'ing the trecor that of the preceding turn. prismg two magnetic circuits independent 55 7, Having described my invention, I claim: of that of the record means for alternately 1. In a telegraphone, the combination of "augmenting said magnetic circuits by the a recording body, a vibratory dia hragm, magnetic clrcuit of the record, anda vibratwo magnets of constant force, an means tory diaphragm influenced altern'atel by whereby the vibrations of said dia hragm said two magnetic circuits, substantia y as 50 will alternately cause the lines of orce of described. 1 said magnets to traverse the recording body, In witness whereof, I. subscribe my signasubstantially1 as deficribedil, Y b f ture, in the presence of two witnesses.

2. In a te egra one, t e com ination o a recording body a vibratory diaphragm, U

two magnets of constant force whose mag- Witnesses: v netic circuits are normally exterior to the FREDERIG SCHAEFER, recording body, and means whereby the vi- -WM., 1). (looks.

in the recording body, com

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