US814411A - Telephonic relay. - Google Patents

Description

1 1111111121) MAR. 6, 1906.

J. TROWBRIDGE. TBL-EPHONIG RELAY. APPLICATION FILED JULY 14, 1906.

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PATENTED MAR. 6, 1906.

. J. TROWBRIDGE.

TELEPHONIO RELAY,

APPLIOATION FILED JULY 14, 1905.

' 5 SHEETS-SHEET z.

PATENTED MAR. 6, 1906.

No. 814,411. 1 J. TROWBRIDGE.

TELEPHONIG RELAY.

APPLIOATIOYN FILED JULY 14, 1905.

5 SHEETSSHEET 8.

PATENTED MAR. 6, 1906.

J. TROWBRIDGE. TELBPHONIG RELAY.

APPLIOATION FILED JULY 14, 1905.

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UNITED STATES PATENT OFFICE.

TELEPHONIC RELAY.

' No..ei4,4ii.

Specification of Letters Patent. 7 Applicatioi filed July 14,1905. Serial No 269.628.

Patented March 6, 190

To all whom it may concern:

Be it known that I, JOHN TROWBRIDGE,&

' citizen of the United States, and a resident of undulated.

Canibrid e, in the count of Hiddlesex and State of assa'chusetts, ave invented new and useful Improvements in Telephonic-Re-- lays, of which the following is a specification. v My invention relates to the art of transmitting electrical undulations; and its object is to so improve the construction of telephonic. relays or repeaters as to eliminate from the transmitted undulations the disturbing influences which are manifested audibly at thereceiver in the form of crepitations which con'- fuse and sometimes suppress eiitirel the in- ,telligible articulations of speech w erewith the telephonic current is primarily excited or "Myimprovements, resently to be described in detail, are adaptab e to many forms of telephonic relays and have demonstrated their capacity to eliminate the undesirable vibra-, tory and percussive disturbances wherewith the operations of most telephonic relays have been impaired.- A descri tion of these improvements as they may e associated with one form of telephonic rela will, however, suffice to instruct those skil ed in the art in the essentials of their structure and operation so that they may be applied to othenforms of rela without the exercise of more than the skil expected of persons trained in the practice of telephony and the manufacture of telephonic instruments. 35

The difliculty which has heretofore attended the o eration of telephonic receivers is attributab le in large measure to the practice of placing the transmitter of the reliily u on or in direct contact with the receiveriapliragm which is adjusted to the magnetic portion of the field, thus loadin the dia hragm at the very point where loading has t e most detrimental eflect upon it. On the other hand,

in order to. transfer to the transmitter of the relay all the articulate vibrations of the receiver it'would seem that direct contact between the two was indispensable. I have discovered, in connection with testsand experiments with telephonic relays, including the relay described in my United States Letters Patent No. 756,434, dated April 5, 1904, that this seemin dead-lock can successfully be overcome an that the coexistence in a relay instrument of independent adjustability and intimate sound-transferring contact of t the transmitter and receiver is quite possible conditions. y, t

In the drawings hereto annexed, Figures 1 2, 3, and 4 are illustrative and explanatory of my invention; and Figs. to 10,1nclusive, show an embodiment thereof. Figs. 1 and 2 show diagrammatically an elementary form.

of relay. Fig. 3 showsthe relay as applied to anfordinary telephonic receiver. 1g. 4 illustrates the application of the elementary principle of Figs. 1 and 2 to a relay such as.

despite the seeming inconsistency of the two shown in my Patent N o. 7 56,434, dated April 5, 1904. Fi 5 is a lon itudinal elevation; Fig.6, a vertical longitudinal section of an in strument which comprises a complete embodiment of my invention. Fig. 7 is a ri ht-hand end, 8 a left-hand end view, an Fi 9 a plan view, respectively,of Fig. 5; and Fig. 10

is a detail showing the arrangement of reinforcin -magnets and the armature associated therewith. Figs. 1 to 4, inclusive, are addressed to the phase of the problem referable -to the difficulties heretofore encountered by reasonof directfattachment of the transmitter to the receiver in a telephonic relay. These figures do not illustrate a full solutio 't. but such part thereof aswill be illuminati in connection with the complete structure ii Fi s.5to 10.

eferring to Fig. 1, D represents the diahragm of a receiving instrument, which may e acoustically vibrated in consonance with the undulations of articulate speech. In'opposition to this'vibrator D there is mounted a supplemental vibrator, shown as a diaphragm D, which in this instance is secured to the end of a short cone R in such position as to receive advantageously the impact of aerial vibrations from the air in the partiallyinclosed space G, whereby the two vibrators are separated. One member of a microphonic transmitter T is secured to or otherwise placed in mechanical contact with the vibrator -D, and the circuit C, with battery B, is connected with the transmitter. members in the ordinary manner, the coils I I of the usual induction-coil transferring the electrical undulations to the line C, which roceeds to a distant receiver. (Not shown in the drawings.) My researches and demonstrations have, however, led me to prefer a form of relay wherein the two vibrators are separated by a much thinner gaseous intermediary than thatsiiggested in Fig. 1. Thus in Fig. 2- the supplemental vibrator D is shown as a thin diaphragm (which should be circular in form) provided with a flange or rim turned toward the receiver-diaphragm D; otherwise the arrangement is substantially the same as that illustrated by Fig. 1. If we regard the diaphragm D, Figs. 1 and 2, as the diaphragm of a telephonic receiver and assume the instrument to be in operation, it is obvious that the transmitter T and the receiver may be independently adjusted and that the gaseous intermediary between the diaphragms D and D, being in free communication with the outside atmosphere, cannot assume a condition of pressure or tension which will impose an load or stress upon either diaphragm. Tl ie transmission of articulate speech from D to D will thus be free from disturbances such as attend the direct attachment of a transmitter to a receiverdiaphragm; but the amplitude of the articulate vibrations will necessarily be materially diminished in transit from the receiver to the transmitter'and the result in the transmittercircuit consequently enfeebled.

In Fig. 3 there is illustrated another mode of securing the benefits of the separation of the receiver-diaphragm from the transmitter-vibrator. The receiver-dia hra m D is mounted in the receiver-she R in the usual way. Secured to the lip L of the receiver the supplemental diaphragm D is stretched across the central aperture of the said lip, and the transmitter T is secured or otherwise telephonically connected to the center of the diaphragm D. In order to insure the freedom of the gaseous cushion G, which separates the vibrators D and D from the eiiectsof unbalanced pressure due to confinement and changes of temperature, I recommend that one or two small apertures L be provided in the lip L. As'before, the transmitter connections to battery-circuit and line are as described with reference to Fig. 1. In the apparatus as shown in Fig. 3 the intervention of the air-gap between the diaphragms D and vibrator D uite efieetively eliminates the disturbances no in other relays to the direct contact between the receiver-diaphragm and the transmitter, while the solid intermediary provided by the ca L between the diaphragms D and D trans ers the mechanical vibrations to the transmitter T far more effectively than the air-gap alone, as in Figs. 1 and 2; but although the solid connection illustrated in Fig. 3 is superior to the disconnected arrangement of Figs. 1 and 2 it is nevertheless not all that could be desired, for the reason that the insulating materials of which the commercial receiver-case is composed is not ideally adapted to sound transference.

The forms of relay above described are not so constructed as to reproduce the electrical undulations of the receiver-circuit with enhanced force and amplitude in the transmitter or relay circuit and-arefor this reason doubtfully effective as relay instruments. Neverthe ess the local disturbances which occur in the transmitter and which (if the transmitter were connected directly to the receiver-diaphragm D, as in sundry early forms of telephonicrelay) wouldreact upon the receiver undulations and produce the rattling and buzzing noises which have in nearly all relay instruments impaired or obliterated the essential articulate character of telephonic undulations are eliminated by the elasticintervening layer of air, which in the instruments shown in Figs. 1 to 3, inclusive, separate the opposed articulate undulations from the receivervibrator D to the supplemental vibrator D with unimpaired quality, and the'undulations transmitted in. the relay-line C C reproduce the articulate speech whereby the on inal sending instrument was excited.

n my United States Letters Patent Nos.

vibrators D and D.- This gaseous cushion, however, transmits'the' correctly 756,436 and 756,437 there are described a,

method and apparatus whereby telephonic undulations are repeated or relayed from one circuit to another not only without loss in amplitude and force, but with both these qualities enhanced. By means of the magnetically-balanced relay instruments shown and described in the said patents-the repetition of telephonic messages can recur indefinitely as additional increments of electromechanical energy are supplied at each station, so that the stations are in truth relays. A full description of this method and apparatus is afforded by the specifications oi the said Letters Patent.

In Fi 4 there is illustrated a mode of applying tIie air-gap connection shown in Figs. 1 and 2 to a relay instrument of the character shown and escribed in Letters Patent No. 7 56,437 and particularly illustrated in Fig. 5 thereof. In Fig. 4 hereto annexed, M.

receiving-line G" contains the armature-coil.

in circuit, and the undulations of current created in that line by a distant sending instrument react magnetically on the field of the magnets M M. Instead of securing the tran smitter T directly to the stem P, I secure it to the supplemental vibrator or diaphragm D, which, as in the instruments shown in the previous Figs. 1 to 3, is separated from the vibrator D by an intervening cushion of free or normally inert gas-1n this case air. The:

form of supplemental vibrator is here shown as the same as that of Fig. 2, and the transmitter connections to battery-cir uit, &c., are as in Fi 1. Theefi'ect of th. balanced armature A- m the field of the magnets M is to enhance the force. and effect of the undulations roduced in the circuit C as these are transfiirred to the transmitter T. The effect of the gaseous cushion or layer G, as in the instruments shown in Figs. l'to 3, is to supress or absorb the reactionary crepitations liable to be produced by the transmitter T. The intervention of the air-ga inthe instrument illustrated in Fig.4 has t e effect of preserving the ,quality of articulate undulations, thoug it necessarily diminishes their force and amplitude, and while this diminution is in part compensated for by the peculiar mode of operation of the receiving portion of the relay shown it is obviously preferable to combine the advantages of air separation with those of continuous solid contact, as suggested by Fig. 3. In all cases I believe it to be advisable to maintain pressure balance as between the gaseous cushion and the circumambient gas, so that there shall be no distortion of either of the op osed vibrators. ,It is also desirable to have the two vibrators quite close together and perfectly parallel as to their opposed surfaces. Concentric arrangement is obviously to be recommended.

In the Figs. 5 to 10, inclusive, there is shown an apparatus which combines the advanta es desirable: first, fromairap separation,wh1ch eliminates disturbances due to load' on the receiver and preserves the quality of the articulations second, from solid continuous sound transferring communication between the receiver and transmitter, and, third, from the enhancement of the force, and amplitude of the received undulations in and by the eculiar structure and 'mode of operation 0 a receiver such as shown and described in my pIatent aforesaid. Referring to the drawings, is a suitable base for the reception and mountin of contact-posts, and N 1s a standard rigid y secured to the base N- Slide-blocks N project from the rear of the standard N and en age the slides O, the slide-blocks N and sli es 0 bein dovetailed to establish their mutual slidin engagement. Differential screws 0, whic are threaded into the slides O and slide-blocks N, control theadjustment of these two parts. The ma nets M are securely clamped between the p ates O and O whereof the former is rigidly secured to the slide 0. These parts are all infduplicate, the arts on either side carrying one of the reinorcing relav-ma nets M. A block N, rig

. idly secured to the standard N, is central aipertured and threaded to receive the shell between which and the block N 3 the susv taming-diaphragm D is secured. Horizon-- tal posts N", secured to the standard N, support the frame-plate Q1, which is provided with lugs Q and Q. e diaphragm D is se cured to a central aperture ln-the plate Q.

The stems P P are centrally fastened to the diaphragm D and D, respectivelg, and carry between them thqrectangular ame A, in which is mounted rhe armature A. This armature has its coil in circuit with a telephoneline, as described in m aforesaid atents. The dia hragms D and 3 are referably constructed ofmica. In a circu ar shallow recess D, formed in the plate Q, there is secured the diaphragm D, wh1ch may be a plain plate of sheet-iron, such as used for commercial receiver-dia hra ms. ,The diaphragm D constitutes t e vi rator for the transmitter T and is separated from. the diaphragm D of the receiver by an air-space, the dlaphra m f the receiver and transmitter vibrator ein opposed to each other, preferably paralle and as close together as the convenienceof construction will allow. At or nearthe margin of the receiver-diaphragm D the ring Q is inserted, WhlCh serves in the 1nstance shown both as the clamp for the margin of the receiver-diaphragm and also as the solid continuous sound-transferring connection between the diaphragms D and D, the diaphragm D being brought into sufficient] continuous and intermittent contact wit the rin% fingers an K. The ring Q in order to obtain satisfactory results should be of metal and be brou ht into intimate contact with the receiver-diaphragm and the transmittervibrator. consistent with a practically free ventilation of the air-s ace between the diaphragms D and D. T is free communication between the air of the space between the diaphragr'ns and the surroundingatmosphere is of value in that the pressure balance between the inner space and the outside air precludes the production of stresses upon the receiver-diaphragm itself or upon the vibrator of the transmitter, ifthat, as in the instance shown,

be also a continuous circular diaphragfii.

The diaphragm D, Fig. 6, is consldera larger in diameter than the diaphragm D, the effective diameter of the latter measured from the inside of the ring Q being somewhat less than half the diameter of the former. The ring Q, bearing upon the peri hery of the diaphragm D, does not inte ere appreciably, probably not at all, with the responsive vibrations of the receiver-diaphragm D. This ring bears u on the larger diaphragm D well within t 1e peri hery thereof, and consequently imparts to t e dia hra in D the vibrations manifested by tile iaphragm D, so as to make their efi'ectfelt emb means of the clamps or spring- This contact, however, is not in-- 'IIO phatically at the center of the diaphragm'D,

whcreon the contact-point of the transmitter T is made to bear. that this proportionand arrangement of the Specifically, it is believed sound-transmitting parts is decidedl effect ive in transmitting the vibrations o the receiver-diaphragm to the transmitter Upon justing devices results in what is in substance justing-bar is inwardly 3 spring T The transmitter T is suspendedl upon a leaf-spring T, which is secured to the 1 upper end of theadjusting-bar T. This adinclmed at its lower end T and the sloping surface of this inwardly-inclined artion is engaged by the end of an adjusting-screw Q wluch is threaded into'the lower lug of the plate Springclamps K K hold the diaphragm D in position in the recess D. The magnets M have polepleces M, which slightly overlap each other as viewed horizontally, Fig. 10, so that the ends of the armature A lie between the overlapping pole-pieces M.

By means of the apparatus above de-' scribed the receiving and transmitting'members of the relay are independently adjustable. The magnets M are adjusted by means of the differential screws 0, which may be operated singly or together, as desired, in order to produce a perfect balance of field around the armature A. The transmitter T, on the other hand, is independently adjusted by means of the screw Q which presses the adjuster-bar T inward or allows 1t to swing outward under the tension of the spring T The mode of hanging and pivoting these ada parallel-motion adjustment for the transmitter T, the radial action of the-spring T compensating for the radial action of the As I have hereinabove stated, in some of the telephonic relays heretofore constructed the contact-piece of the transmitter has been placed in direct contact with or has been secured to the diaphragm of the receiver. This arrangement has stood in the way of the obtainment of satisfactory results, because the securement or contact of the transmitter unduly loads the receiver-diaphragm and it is impossible to make adjustments in the transmitter without undesirably affecting the receiver. Moreover, all the disturbances and crepitationsdue to the operation of the transmitter are directly transferred to the receiver, and the articulate speech originally transmitted by the line is confused, or it may be wholly suppressed. By separating the vibrator which is in connection with the transmitter from the vibrating diaphragm of the receiver by a thin layer of air between the directly-opposed portions of the vibrator and diaphragm the consequences of too direct an intimate contact between the transmitter and the receiver-diaphragm are avoided, and either instrument may be adjusted independently of the other. Furthermore, by con structing the instrument so that the communication of vibrations from the receiver-diaphragm to the transmitter are through a path of solid continuity, as through the ring Q and the diaphragm D, the transmitter is put into communication with the receiver just as effectively, for all practical purposes, as it is when it makes its contact directly with the receiver-diapln'agm. All of the articulate vibrations of the receiver-diaphragm are passed to the transmitter, whereas by reason of the air separation between the vibrator and the diaphragm the inarticulate disturbances of the transmitter are not communicated to the receiver. Thesecurement of the diaphragm D leaves a circumferential clearance which is not air-tight, so that the pressure balance between the air in the cushion G and the surrounding atmosphere is maintained. 4

One feature which I regard as practically of great importance is the independent adjustability of the receiver and transmitter members of the relay. As these two members are separated by a layer or cushion of air, it is quite obvious that the adjustment of one can be carried on entirely independently of the other, whereas in those instruments whose structure involves mechanical contact or other mechanical connection between the receiving and transmitting members of the relay the pro )er adjustment of one is very liable to affect t e adjustment of the other, and very nice compromises of adjustment have consequently to be resorted to. Moreover, the vibrating portion of the relay, which is set in motion in the magnetic field by the undulations of the current to be relayed, is entirely relieved of the load or restraint of the transmitting-microphone or other transmitting device.

With respect to the transmission of. articulate speech as yet no instrument has attained such perfection as the mierophonic transmitter. This transmitter in the usual commercial solid back form is provided with its diaphragm for the reception of articulate sound-waves. In my improved relay I employ just such a transmitter and subject it to conditions which closely resemble, if they do not exactly reproduce, the usual conditions presentwhen a person speaks to the microphonic transmitter. The vibrator of the receiver reproduces with accuracy the articulate sound-waves emitted by the human voice into a distant transmitter, and the receiver vibrator or diaphragm emits'this articulate vibration, setting the objects immediately in contact with it into exactly similar undulations. The transmitter vibrator or diaphragm is subjected to the soundwaves which impinge upon it as effectively as when it is spoken to in the ordinary way. where, as in the instrument described in my patent aforesaid,,a relay-station is provided with an instrument which enhances the force and amplitude of the articulate vibrations of loudly, the vibrator of such a relay is enabled the telephonic circuit, so that the receiver of the relay mav speak not only intelligibly but to speak to. the vibrator of a transmitter with exactly the same force and ell'ect as though the person originally sending the message spoke directly into this transmitter.

,What I claim, and desire to secure by Letters Patent, is-

1. In a telephonic relay, a receiver, its diaphragm, a vibrator opposed to the receiverdiaphragm, an air layer between the vibrator and diaphragm, in free communication with the circumambient atmosphere, a transmitter in connection with the vibrator, and continuous solid sound transmitting connections betweenthe vibrator and the diaphr 1n.

2. n a telephonic relay, a receiver, its diaphra m, a vibrator op used to the receiverdiap ragm and space therefrom, a transmitter in connection with the vibrator, and a close metallic connection between the .vibrator and the diaphra m.

3. In a telephonic relay, a receiver, its diaphragm, a vibrator op osed to the receiverdiaphragm and space therefrom, a transmitter in connection with the vibrator, and a close metallie'connection between the vibrator and the diaphragm at the margin of the latter, to insure sound communication and to permit mutually independent 'adjust-. ment of the transmitter and receiver, and means to adjust the transmitter independently of the receiver. 4. In a telephonic repeater, the combination of a receiving instrument and a transmitter, each provided with a dia hragm, the diaphragms arranged arallel an opposed to eae other, separated y an intervening layer of air which is in free communication with the surrounding atmosphere, the transverse area of said air layer being substantially at least coequal with the area of the smaller diaphragm, and solid sound-transmitting connections from the edge ofone diaphragm to the edge of the other.

5. In a telephonic repeater, the combination of .a receivim instrument and a transmitter, each provided with a diaphragm, the

diaphragms parallel and opposed to each other separated by an intervening layer of air whic is in free communication with the surrounding atmosphere, the transverse area of said air la er being substansma er diaphragm, and solid sound-transmitting connections from the edge of one diaphragm to the edge of the other, and means to adjust the receiver and the transmitter independently.

6.In a telephonic repeater, the combination of a receiving instrument and a trans-. mitter, each(provided with a diaphragm, the transmitteriaphragm of larger effective superficial area than that of the receiver, and a solid sound-transmitting connector which bears upon the periphery of the receiver-diaphragm and upon the transmitter-diaphragm etween the eriphery and the center thereof.

7. In a te ephonic repeater, the combination of a receiver and a transmitter, each provided with a diaphragm, the transmitter diaphragm of substantially greater superficial area than that of the receiver, the two diaphragms separated by an intervening layer of air which is in free communication with the surrounding atmosphere, and a solid soundtransmitting connector bearing upon the receiver-diaphragm at the periphery thereof and upon the transmitter-diaphragm between the periphery and center thereof.

8. In a telephonic repeater, the combination of a receiver and a transmitter, each pro vided with a diaphragm, the transmitter-diaphragm of su erfioially greaterarea than the re'ceiver-diap. ragm, the two diaphra ms concentrically arranged and in paralle opposition, and a ring of solid sound-transmitting material interposed between the dia hragms and bearin upon the periphery of the receiver-diap ragm and upon the transmitterdia hragm at a region between the center an periphery thereof.

Signe by me at Boston, Massachusetts, this13th day of Jul 1905.

- 7 J0 N TROWBRIDGE. Witnessesz.

JOSEPH T. BRENNAN,

CHARLES D. WOODBERRY.

tiallfi at least coequal with the area of the

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