US1558881A - Loud-speaking telephone - Google Patents

Description

ou. 27,1925. A 1,558,881

' M. C. lHOPKINS l LOUD SPEAKING TELEPHONE Filled May 9'1924' 2 Sheets-Sheet 1 I '1 l g Y I A /0 i 9 f3 7a l 5 7 A )T b 4( f5 I l \l l 'A I L;

il. a f I. a l L l f1 I C Y y g f e l s ,Q /6z y A' /4 h] li lllllllll Zi 1925i 1,558,881`

M. C. HOPKINS LoUD SFEAKING TELEPHONE Filed May 9 1924 2 Sheets-Shut 2 INVENTOR 5 lniprovements 15 a telephone reeeivm instrument an( :so receiving instruments.

atented Oct. 27, 1925.,

nutren STATES 1,558,881 PATENT oFF'IcE. l

MARCUSC. HOPKINS, OE WASEZVNGTON, DISTRICT OF COLUMBIA, ASSIGNOB, BY DIRECT AND MESNE ASSIGNMENTS, TO HOPKINS CORPORATION, A CORPORATION OF DELA- WARE.

Application led May 9,

To all whomzzf m11 concern:

Be it known that I, Marions C. llornixs, residing at 1ilVashington, District ot' Columbia, havenvented-cetain new and useful in Loud-Speaking Telephones; and Ido hereby declare the following to be a full, clear, and exact descriptlon of the invention, such as will enable others skilled in the art to which it appertains to io make and use the saine.

This invention has to do with telephone receivinginstruments and more particularly instruments ot the loud speaking type.

The invention Ahas'or its object to rofluce particularly a loud spes ing telephone 1nstrument, characterized by increased'etiiciency and improved quality-of reproduction.

It is a matter of common knowledge that ce the cilciency of ordinaryntelephone receiving instruments is very'low, and hence that the volume of sound produced by such instruments is small as compared with the elecn trical energy required to operate them. In

:5 line, with the obg'ect ot obtaining increased efficiency the invention is directed toward decreasing as mach as possible certain of the electrical or magnetic losses which account for the low etticiency of ordinary telephone The invention contemplates a magnetic ltelephone structure having' a diaphragm pivotally supported on an annular fulcrum concentric therewith and ot smaller diameter than the dia- :.5 phragm; a permanent magnetic field acting ou the diaphragm both inside and outside the annular fulcrum so as to give the diaphragm a substantially balanced bias; and an electromagrnctic field energizablc in ae- Vio cordance with electrical signaling iml'iulscs and arranged so as to actuate the diaphragm inside and outside the annular fulcrum altcrnately. The structural and electrical arrangement thus defined provides what 4.3 amounts to a pushpuli actuation of the diaphragm and results. not only in markedly increasedA oliiciency. but in materially improved quality-ol' reproduction.,

n addition to the novel feature of con.-

o struction referred to above, a` further feaef the back et the diaphragm to the open air.

/ :Loon-SPEAKING TELEPHoNE.

1924. Serial N'o. 712,012.

Still another feature ofthe invention consists in the provision .of permanent magnets ot' helical torni, by which arrangement the permanent magnetic elements can be made of the desired length-thus securing,r the necessary magnetic potcntials-but at the Same time keeping the size of the structure within reasonable limits.

`Other features reside in the details of construction. which can be more 'readily brought out in the description which follows:

With reference to the accompanying drawing:

Fig. l is a vertical cross-section of a loud speaking telephone instrument representing onel ot' the preferred embodiments of' the invention,

Fig. 2 is an elevational View correspondiner to Fig. l,

Fig. 3 is a horizontal cross-section along the lines 3-.-3 ot' Fig. 1, and

Fig. 4 is a horizontal cross-section along the line 4 4 of Fig. l

A pressed or spun, iron7 or soft steel member l and an annular member 2 of the same material are assembled together and form, in combination, a channel in which is seated a ring winding 3 which isthe actuating winding of the device; A

A ring 4 preferably of hard rubber or some other suitable non-metallic substance is supporter1 on +he winding 3 and positioned concentrically with respect thereto. Thering; 4: is formed with a pointed annular projection on which is supported a magnetic diaphragm 5. lVth the ring 4 properly positioned, a suitable filler of self-hardening substance such as beeswax, or one of the well known insulating compounds, is poured intothechannel. Upon hardening, this filler serves to hol-d the winding and ring 4 in place.

The portion of the structure abovethe diaphragm comprises a circular plate 6 preferbaly of iron or soft steel, a ring 7 of the same material attached to the plate 6 by' mcans'ot' round head screws S anda throat member 9 which may be conveniently made of brass. The ring 7 is channeled at 7- to form a recess in which is seated a strip of soft rubber tubing 10. The tubing l() bears against the diaphragm 5 in opposition to the ham its

pcash-1m;

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. snppm "-2 of suffi-,mut vngth to miem fmge l WSH @have w surface Cf Hw conceal the magneticarsi'l, and generally improve the appgaragucefof the device.

Thetyp'e otwinding used vvin the strueture herein described is particularly' desir able in that it permits cfa very large' 'numher of ampere' turns ata comparatively low ohmic resistance, thereby materially reducing resistance losses and consequently inenI TCD

"sii

creasing the eiiiciency of the instrument.`

ln an instrument substantially as disclosed herein, which has been constructed and successfully operated, the diaphragmv is of silicon steel, 3 inches in diameter, .015 inch thick; the diameter of the annular fulcrum is 213g inches; the diameter oi the opening at f is .131% inches; the diameter of t e opening at g is 12,35 inches; the air-gaps are each approximately .010 inch; members l and 2 are each'made oi cold rolled steel inch thick; and the winding 3 consists cfl turns of No. 33 enameled copper wire.

y For che purpose of preventing losses due to eddy currents, members l and 2 are preferabiy slotted through as indicated at in Fig. 4.

This invention is capable of embodiment in many difiere-nt forms aud'should not be yconstrued as limited except as indicated by the subjoined claims:

l claim:

l, ln atele'phone instrument, means for maintaining e continuous magnetic field, a. diaphragm therein, 'supporting means `for said diaphragm, theperipheral portion of said diaphragm extending beyond said supporting means,'and 4magnetic means operable to actuate the peripheral portion of 'said diaphragm.

2. ln a elephone instrument, a diaphragm, supporting means for said diaphragm, the peripheral portion ot said die phragm extending beyond said supporting means, and magnetic means operable on said diaphragm at points thereon both inside and outside said supporting means to magnetically actuate both the peripheral p0rtion and the center portion of 'said diaphragm.

3. lin a telephone instrument, a diaphragm,/siipporti1ig means comprising an annular member on which said diaphragm is supported,'the peripheral portion of said diaphragm extending beyond said annular' member, and actuating means adapted to act upon said diaphragm at points of ap'- plication thereon both inside and outside the area', thereof encompassed by said annular meinber,

lifn a telephone instrument, a lldiaphragm, an annular 'support-ing member for said diaphragm, Asaid supporting member 'being mi smaller diameter than said diaphra n, and electromagnetic means for actuaifing said diaphragm, sind electromagnetic means being adapted to act magnetically upon said diaphragm at points thereon both inside and outside the area thereof eu- ?)ompassed by said annular supporting mem- In a telephone instrument, a diaphragm, an annular supporting member for said diaphragm, said supporting member being ot' smaller diameter than said diaphragm, a permanent magnetic fie-ld having parallel ux path-s through the portions of said diaphragm inside and outside the area thereof encompassed by said annu r supporting member respectively, and -electromagnetic means operable in response to current im ressed thereon to increase the mag netic ux assing through one of sald parallel pat is while vdecreasing themagnetic flux passing through the other of said parallel paths f and vice versa depending upon the direction of impressed current.

6. In a telephone instrument, a diaphragm, an annular supporting member for said diaphragm, said supporting member' being of smaller diameter than said diaphragm, a pair of annular magnetic poles, one of seid lesgbeing Yadjacent the p'orticn of said diap ra within the area encompassed by sail su p`ortin member, the other of said oies ing a jacent the portion of said riaphragm outsidesaid area, meahs for opposltely and variably energiz ing said poles inaccordance with correspondingly variable currents, whereby said diaphragm is actuated, andn means for impressing a. continuous magnetic potential of the same polarity on each'of said poles.

7. In atelephone instrument,adiaphra m, an annular fulcruin, on which 4said phragm is supported, the diameter oi said fulcrum being substantially less. than the diameter of said diaphragm, resilient means for holding said diaphragm against said fulcrum, and electro-magnetic means operable to act magneticallyon said diaphragm at points inside and outside the area encompassedvby said annular fulerum,

8. In uitelephone instrument, a diaphragm,

an annular fulcrum on which said phragm is supported, the diameter-.of said t ulorum bein substantially less than the dif ameter of sai diaphragm, an annular chanv nel of magnetic material, Van electro-magnet y coil supported in said channel, the extremi ties of said channel formingumagnetic poles, one of which is disposed closel adjacent the portion of said. diaphragm within the areaencompassed by said annularv ulcrum, the other of said poles being disposed closely adjacent the portion of said diaphragm outside said area, the magnetic potentials of said poles caused by said coil being of opposite polarity, and means for impressing a continuous magnet-ic potential of the'same polarity on each of said poles.

iin e 'elephone instrumen, n. diaphragm, en annuler supper-ning member for Saki. die'- phrsggin seid snpporing member being of smeiei diurnes/e5;- than said diaphragm, ineens or producing e continuous magnetic s: means having opposite magnetic cl, oserl respectively on opposite sides ci i? nphregm., and adizicen/ thereto, one esi( poles being hiurcned, the branches i ,ii oi-furciiteil pole being disposed ML scent seni diephrngm at points 'wihin Athe aree, hereo encompassed by said supporting member and. outside said oren respectiveiy, and an eiecronmgnet for actuating seid diaphragm, the branches of said hi Hurceled pcie forming opposite poles of said electrom insignes respec'ivelv.

l0. in 1 eleplione instrument, e diaphragm, en annuler ulcruni supporting said diaphragm., said nlcrmnh being of smaller diameter "than said dinphregnn means lfor producing e continuons magnetic field, said ineens having epposiie simgnezic poles of nnnnisr form disposed respecirely on opposie sides o1? seid diaphragm and adjacent thereto, thet one of seid poies which is on che. opposite side of sniiiiinphrngni from ulcrnni being disposed suhstaniniiy opposie said nlcrnni., resilient means interposecl hein/een seicilast men'ioned pole und saisi ahr-ogm emi hearing against seid {iiephragrn in oppesiion to said uicrum, lie other of seid. poles heing hi-'furcaerh the branches of, seid hifnreaceei pcie being dis pwed mijncent #diaphragm ai' points within he area ih reef encompassed hy said ifnicrnni inni ouiside said aren resoeciively,

and :in eieerro-megne coi disposed heatn'een rthe 'branches olif .seid iii-forested pole, the extremities of the branches of said iii-furenteci pole forming opposite 'poles of the elecromagnetic ield of said coil, said coil being opcrahle upon energization to efi'ect actuation of seid diaphragm.

l1. In a teiephone insrument, a diaphragm, means for producing a continuous ma fnetic eid for said die hm n1 saidV ineens comprising s, permanently magnetized thereof alternaely.

'14. The .method c operating a sound producing diaphragm which consists in applying u plurality of continuous magnetic ab trncting' forces to the diaphragm in physical opposition und ai substantially different (lisances' from he center of the diaphragm, und super-imposing iuctuating magnetic forces on said continuous magnetic forces in such nmnner that ehe resultant forces up plied ro the diaphragm are' altered in dierent degrees thereby causing sound producing rlisp'ecernens of the diaphragm. Y

En testimony whereof ax rnk signature.

MARQUE C. Hf FKNS.

Cil

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