US1414105A - Telephone receiver - Google Patents

Description

J. S. TIMMONS.

TELEPHONE RECEIVER. APPL'ICATiON FILED 1uLY17. 1918.

14,414, 105. Patented Apr. 25, .1922.

2 SHEETS-SHEET I.

3 vwewfoz M anon 121 a @Md 1.3. THVIMONS.

TELEPHONE RECElVER.

APPLICATXON FIL'EDJULYI7,1918.

Patented Apr. 25, 1922.

2 SHEETSSHEET 2 JOHN S. TIMMONS, OF NEW YORK, N. Y.,

ASSIGNOR, BY MESNE ASSIGNMENTS, 110

INTERNATIONAL CALLOPHONE CORIPORATION, A CORPORATION OF DELAWARE TELEPHONE RECEIVER.

Application filed July 17,

To (all whom it may concern.

Be it known that 1, JOHN TiMMoNs, a citizen of the United States, and a resident of New York city, county and State of New York, have invented certain new and useful Improvements in Telephone Receivers, set forth in the following specification.

This invention relates to electro-magnetic sound functioning mechanism, particularly of the type reproducing sound in response to a sound controlled electric variation, although including the type in which sound is employed to produce a corresponding electric. variation through the variation of a magnetic circuit. More particularly, the invention relates to the species of this general apparatus commonly known as a telephone receiver.

The object of the invention is to improve the faithfulness of the variation with relation to the essentials of articulate speech, particularly the faithful reproduction of articulate sound, but likewise the creation of an electric variation in response to articulate sound. More particularly the object of the invention is to improve the sound functioning vibration of a diaphragm of electromagnetic material in mechanism of the above gei'ieral type. To this end an improvement in the form and construction of the permanent magnet of such a mechanism is contemplated. A novel and improved disposition of the permanent magnetic field with relation to the diaphragm is also contemplated and a functioning objective feature is an inertia-less loading of a sound functioning diaphragm to prevent false vibrations or vibrations of a character tending to interfere with the faithful rcproduction of the essentials of articulate speech.

,I urthcr objects'of the invention are to improve in general the structural parts and structural arrangement of a mechanism of the above general character. the general fea tures of this latter object being simplicity,

ruggedness and compactness.

The above and further objects of the invention will be clear from the illustrative embodiment to which the claims are directed merely for purposes of illustration and which is described in the following speci Specification of Letters Patent.

Patented Apr. 25, 1922.

1918. Serial No. 245,386.

lication in connection with the accompanying drawings, which form a part hereof. and in which like characters designate corresponding parts in the several figures.

In the drawings, Fig. 1 is a horizontal section through an illustrative embodiment of the mechanism;

Fig. 2 is a section through line IIIZ Fig. 1, looking in the direction of the arrows;

Fig. 3 is a diagram of the magnetic circult;

Fig. at is a side elevation of the mechanism with the casing open;

Fig. 5 is a diagram drawn to a reduced scale showing the magnetic lines of force on the outer face of the diaphragm;

Fig. 6 is a similar diagram of magnetic lines of force with the diaphragm removed; and

Fig. 7 is a similar diagram showing the magnetic lines of force with the diaphragm removed of a telephone receiver of the ordinary commercial type.

In the illustrative embodiment the hollow casing A of nonmagnetic material, preferably bronze, comprises a cover portion 1. and a base portion 2 mutually provided with threads 3 by which the two parts, 1 and 2, may be clamped together. The cover portion 1 is shown providing the cylindrical rim 1- of the casing as an integral. part thereof, although of course it is not deemed essential that this be a part of the cover por tion instead of a part of the base portion. The cover portion provides a circular seat 5 for the (:liaphragm G of electro-magnetic material, which seat surrounds the countersunk resonating space 7, leading into the sound. opening 8, preferably :l'ormed in a nipple 9 having threads 10 to engage in any suitably perforated and threaded support ll, which may be a part of a horn mechanism, or mounting block or mouth-piece, but which forms no detail part of the present invention. It is preferred that the diaphragm seat 5 be provided with a packing ring or circular gasket 12 of suitable material such as fiber, hard rubber or the like, capable of making a hermetica-l closure when clamped against the rim of the diaphragm 6.

The base portion 2 of the casing A provided with perforations 13 and 14 to seat the insulating bushings 15 providing a mounting for the binding posts 17 and 18. The base portion 2 likewise preferably formed with a pair of diametrically spaced sockets 19 and 20 to accommodate a spanner to facilitate the assembling of the apparatus.

A ring shaped permanent magnet B is. formed preferably as an endless ring having diametrically arrangedpolarity, as indicated in the diagrams of Figs. 3, 5 and 6, so that its north and south poles N and S are on diametrically opposite sides of a central. zone indicated by the line C of neutral polarity. Functionally it is understood that the ring l3 need not be endless, although such form is preferable for structural reasons.

A pair of soft iron cores D, preferably L-shaped' and comprising the cores 22 and 23, are connected so that the outer ends of the legs 24: and 25 are suitably intimately connected, preferably by welding, to the permanent magnet B at its rim at the locality respectively of the north and south poles. These legs 2i and 25 extend inwardly radially and continue integrally into the axially extendin legs 26 and 27; which terminate in pole faces 28 and 29 approximating"the plane of the diaphragm seat 80; formed. by the outer forward rim ofthe ring shaped permanent magnet B, which is preferably faced with a gasket 31, like the gasket 12. The edge of the magnet Bis also preferably provided with a bevel 82'back of the diaphragm 6. The legs 26 and 27 of the cores 22 and 28 provide a convenient mounting for the electrical controlling bobbins 84: and 35, which provide the controlling winding for the instrument, the terminals 36 and 37 of which are suitably connected as by means of soldering with the binding posts 17 and 1.8.

The base portion 2 of the casing" A is preferablyv providedwitha countersunk channel 38 to accommodate the legs 24 and 25 which loosely seat therein. The entire magnet structure may be held assembled to the base portion 2 in a convenient manner permitting self-seating of the diaphragm seat by means of a pair of screws 40 and if screwing into the base portion and passing loosely through perforations 41-2 and 43 in the legs 241: and 25. This loose connection serves to protect the terminals 36 and 37 against damage when the casing A is open. in completing the a semblage of the apparatus the cover portion is screwed home on the base portion 2, whereupon the diaphragm is uniformly clamped betweenthe seat formed on the permanent magnet B and the seat formed on the cover portion 41,. gaskets forming at hermetical closure between the interior of the casing A and'the sound ductS. v

It is preferred thata pair of set screws 4: 1-

and a5 pierce the base portion 2'to engage" the elbows of the L-shaped cores 22 and 23 so that after the casing A is screwed together, a nicety of adjustment of the pole faces 28 and 29 relatively to the diaphragm 6 may be effected by slightly bending the resilient cores 22. and by an adjustment of the set screws ll and 4:5. .It is to be understood, however that this adjustment is not an essential feature of the invention.

It is to be noted that the diaphragm is seated upon a circular ring itself forming the permanent magnet of the eloctro-magnetic sound functioning mechanism. With the polarity of this permanent magnet dual and diametrically distributed, it has been found that the magnetic lines of force distribute themselyes when the diaphragm 6 is in place, substantially as indicated in Fig. 5; There is a dense central zone between the localities of the pole faces 28 and29 and a second zone 51 symmetrical about the neutral line C approximately bounded by concave arcs 52' and 53, which second zone is dense but not so. dense as that 50 directly between the poles. lVith the diaphragm 6 removed the, distribution of the magnetic field has been found to be as thatindicated in Fig. 6. The denser zone 50 corresponding to the zone 50 now embraces the hold area of the pole faces 28 and 29, while the zone 51 is of greater extent. being bounded by smaller arcs 52 and 58. The zone of. magnetic force 51 or 51- is substantially. constant and, involving as it does alarge extent of the area of'tlie diaphragm o,.serves as a magnetic load or inertialess load upon the diaphragm which increases in extent as its distance from the center of the diaphragm increases. This magnetic held remains substantially constant during the operation of the mechanism,

the magnetic varyingef ect due to the elec- V tric circuit through the coils Set and 35 being for the most part localized between the pole faces 28 and 29 of the cores 22 and 23, so that this effect is localized upon the central portion of the diaphragm as designated particularly in Fig. 5 by the denser area 50 of the magnetic field. In the diagram of Fig. 3 the magnetic circuit is also indicated the major circuit through magnetically conducting material. being straight across from the north pole N to the south pole S through the 2 cores 22 and 23, which being brought forward by their axially extending leg 7' 2?, causes the field to extend through the central portion of the diaphragm. The remainder of the hold. through conducting material between the poles N and this the parallel field indicated by 5i and 51 in Figs. 5 and 6. The return path. of course. is the leahage path through the air. The unique character of this field through the dia phragm is best un stood by comparison to the field 60 indicated in the diagram of '5 between the pole faces 61 and 62 of a telephone receiver of ordinary construction, in which the permanent magnet is so far separated from the plane of the diaphragm that practically the entire magnetic field involving the diaphragm is that immediately springing from the pole faces themselves. The diagram of Fig. 7 has been plotted with the receiver diaphragm removed and substituted by a sheet of nonmagnetic material, as was the case also in the making of the dia gram of Fig. 6, iron filings in all cases being employed as the visible indication of the field.

Although it is not generz'rl to employ a mechanism of the type described for purposes of transmitting speech, it is to be understood that this mechanism is capable of such operation. Furthermore, it is to be understood that the preferred embodiment illustrated has been set forth merely for purposes of illustrating the invention. All modifications within the scope of the accompanying claims are contemplated.

lVhat is claimed and what is desired to be secured by United States Letters Patent is:

1. An electro-magnetic sound functioning mechanism comprising, a ring-shaped permanent magnet providing a diaphragm-seat about one edge and having diametrically opposed poles; a pair of cores extending radially and axially of said magnet and fixed to said magnet at diametrically opposite positions and presenting pole faces in approximately the plane of its said diaphragm-seat and a diaphragm of magnetic material seated on said seat with its central portion under the control of the field between said core pole faces while the other portions of said diaphragm are subjected to the inertialess load of a shunt magnetic field of substantially constant strength.

2. An electro-magnetic sound functioning mechanism comprising, a closed ring-shaped permanent magnet having a diaphragmseat about one edge and having its magnetic poles located in diametrically opposite positions in the body of said ring, in combination with a diaphragm of magnetic material upon said diaphragm seat.

3. In an electro-magnetic sound function ing mechanism, a diaphragm of magnetic material in combination with a pair of per manent magnet-poles in magnetic connection with said diaphragm at diametrically opposite localities; a pair of cores magnetically connected with said permanent magnetpoles and having pole faces radially inwardly positioned against said diaphragm; and coils on said cores.

4. In sound functioning mechanism a vibratory diaphragm of magnetic material; means for producing a dense permanentmagnetic field throughout an extensive area of said diaphragm including centrally lo- "and poles of cated cores of opposite polarity having pole faces localizing a relatively denser portion of said field centrally of said diaphragm alternate polarity spaced about the periphery of said diaphragm; and an electrically controllable winding for said cores in electro-magnetic cooperation with said relatively denser portion of said field while the remainder of said field. is maintained substantially constant to act as an in ertialess load upon said diaphragm.

5. A telephone receiver comprising a hollow casing having a base-portion and a cover-portion, both of non-magnetic material and having a clamping diaphragm-seat on said cover-portion; a permanent magnet and core structure having a diaphragm-seat; and means loosely attaching said permanent magnet and core structure to said base-portion, so that when said casing is closed together said diaphragm-seats will selfregister uniformly and so that said permanent magnet and core structure is main tained in assemblement relatively to said base-portion when said casing is open.

6. In a telephone receiver, a clamping twopart casing; a permanent magnet; a core secured to said permanent magnet at one end and being bent so that its other end forms a diaphragm cooperating pole face; a diaphragm clamped by said casing opposite to said pole face; means operable outside of and reacting against said casing and engaging said core to bend the same against its inherent resiliency for the purpose of effecting an adjustment in the position of said pole face relatively to said diaphragm and a loose connection for holding said core to one part of said casing to maintain the operative re lation between said core and said means operable outside of said casing for effecting an adjustment in the position of said pole-face.

7. In a telephone receiver, a casing having a base member; a curved permanent magnet; soft iron cores secured to said permanent magnet; windings on each said core; electric connections extending from said windings through said base member; a loose mechanical connection between one or both of said cores and said base member comprising a screw engaging said base member and pass ing loosely through said core, whereby the parts are retained in essemblage while a limited movement between said permanent magnet with its attached cores and said base member is permitted.

8. In a telephone receiver, a ringshaped permanent magnet; L-shaped soft iron cores secured to said magnet at diametrically opposite positions and extending first radially inwardly and then axially at right angles to form diaphragm cooperating pole faces; a casing of non-magnetic material for enclosing the magnet structure; a pair of screws passing through said casing to on gage respectively the radially inward portions of said cores whereby an adjustment of the same may be effected through theme dium of their resiliency from outside of said casing; and a loose connection between one or more of said radial inward projections and said casing to maintain registry between said screws and said radial inward projections.

In testimony whereof I have signed my name to this specification, this 16th day of July, 1918. i

JOHN S. TIMMONS

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