US1771127A - Telephone magnet system - Google Patents

Description

July 22, 1930. R. T. KINGSFORD TELEPHONE MAGNET SYSTEM Filed Dec 16 IN V EN TOR.

, 151 ATTORNEY.

Patented July 22, 1930 UNITED STATES PATENT OFFICE vRUSSELL T. KINGSFORD, F WYNCOTE, PENNSYLVANIA, ASSIGNOR TO ATWATEB. KENT MANUFACTURING COMPANY, 0F PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA TELEPHONE SYSTEM Application -tiled December '18, 1926. Serial No. 155,158.

My invention relates to telephonie apparatus, and particularly to' amplifying telephones, loud speakers or radio speakers, utilized in connection with radio receiving apparatus. y

In accordance with my invention, the electro-magnetic system comprises a plurality of spaced field yokes or frames, preferably permanently magnetized, having on opposite sides poles of opposite signs, with inwardly projecting pole pieces comprising overlying pole iece extensions between 'which is received) the free end of a vibrator-y reed, armature bar, or the like, secured at its other end to the aforesaid yokes or frames or one of zthem. i

Further in accordance with my invention, the aforesaid inwardly' projecting pole pieces are bifurcated to form sets of facing pole piece extensions; one set of which, and, preferably the set most removed from the point of attachment of the reed or armature bar to its supporting structure being brought into loverlying relation, while the other set, in this case the one nearest the said point of attachment lies in a substantially common plane to provide a shunt path for the magnetic flux traversing lengthwise the vibratory reed or armature.

Further in accordance with vmy invention, the air-vibrating diaphragm or tympanum of paper, metal, or other suitable material, preferably o'f large area or diameter and preferably conical is supported solely by a member substantially non-flexible in a directioncoinciding with the gravitational plane of the diaphragm and of relatively ,great flexibility in a plane at right angles to said gravitational plane;

Further in accordance with a preferred form of my invention, the aforesaid vibratile armature or reed extends axially of thecoil lor winding traversed by the sound-representin current, whichcoll or winding is suitlab y supported upon stati :mary parts such as the pole piece extensions, preferably by separate members carried thereby and so constructed and arranged that lateral -movement of the coil or winding with respect to the vibratile reed is prevented.

My invention resides in the system, appa-y ratus and features of construction of thecharactcr hereinafter described and claimed. For an understanding of some of the forms my invention may take, reference is to be had to the accompanying drawing in which:

Fig. 1 is a side elevational view of a telephone magnet system constructed in accordance with my invention.

Fig. 2 is a vertical sectional view taken on the line 2 2 of Fig. 1 looking in the direc 6, partlyin'section, showing the coil and its supporting members.

Fig. 8 is an enlarged view, partly in ele-l vation and partly in section, of the structure shown in Fig. 7

Fig. 9 is a perspective view of a coil sup porting member. Fig. 10 shows an alternative coil arrangement which can be usedwith other parts as before described. W

Referringt'o the drawings, there is illus,- trated a magnet system comprising the platelike yokes or frames A, A, preferably duplicate in character and each cut away or recessed interiorly thereof to define a substantially rectan lar opening. `Disposed between the yo es A, A isthe vibratile mem ber, reed or armature 1 on either side of which, adjacent one end thereof, is disposed a washer 2 of magnetic or non-magetic Inaterial, preferably, however, non-magetic in character as brass or the like, through which washers and the perforated end of reed 1 extends a bolt 3 or the like for holding the parts in assembled relation. To the end that the yokes A, A may be held in parallel relation or substantially so, at the end thereof removed from the bolt 3, there is provided the spacing Washer 4, likewise either magnetic or non-magnetic in character, but preferably non-magnetic and of brass or the like, and whose thickness corresponds substantially with the combined thickness of reed l and Washers 2. Passing through this end of frames A, A and washer 4 is the bolt 5, preferably corresponding with bolt 3.

- Secured between the yokes or frames A, A by the bolts of screws 6 are the inwardly extending pole pieces 7, each of which isv bifurcated to form the spaced pole piece extensions or end portions 8 and 9. The extensions 8 are offset in opposite directions and disposed in lsuperposed or spaced relation for the reception of the free end of reed 1. The pole piece extensions 9 are not offset, as are the extensions 8, but are extended in suitable close relation to the edges of the reed 1 to thereby provide a shunt path for the magnetic flux threading through said reed by virtue of the coil or winding associated therewith and which is traversed by fluctuating voice or sound representing current, such as exists, for example, in the anode circuit of a detector or audio frequency amlifier as utilized commonly in radio receivmg circuits. g

Vthile I prefer to o'set the pair of pole extensions 8 which are adjacent the free end of the reed, the reverse arrangement of offsetting the pair 9 and keeping the pair 8 not offset and in close' relation to the edges of the reed may also be used.

Referring to Fig. 9, there is illustrated for the aforesaid coil C a mounting or supporting member M, preferably of brass or other non-magnetic materia-l. Member M comprises a relatively plane surface 10 terminating in the flange or angular portion 11, which, in turn, terminates in the portion 12 extending substantiall parallel with surface 10 and from which and the member 11 extends the portion 13 substantially at right angles with resv ect to both. Adjacent its other end, mem er 10 'is offset as indicated at l0 and the portion thus odset terminates in the flange or angularportion 14 provided with the angular extensions 14.

For supporting the-coil C and holdin the same in suitable spaced relation witr respect tothe reed 1, there are utilized 'two of the supportingymembers M. The pocket formed at the end of each member M by the intersecting portions 11, 12 and 13 is fitted over a pole piece extension 8 in such manner that portion llengages that face of the extension 8 nearest the spaced extension 9 Fig. 5, while portion 12 overlies the outer pole piece extension face or that face parallel with and most removed from reed 1 Fig. 7 and portion 13 overlies the end of said pole piece extension. Accordingly, the plane surfaces l() of each member M extend toward the pole piece extensions 9 substantially in the plane of their respective outer surfaces. However, since the odset portions 10a of each member M extend toward each other, and since the flange 14 overlies the pole piece extensions 9, Fig. 1, it results that the odset portions 10a constitute shoulders, each of which engages the face of a pole piece extension 9, Fig. 8.

The coil C may be supported directly on the aforesaid members M but preferably there is interposed therebetween the layer or strip 15 of paper, cloth or the like.

The members M function primarily as a support for the coil C to hold the same in suitable spaced relation with respect to the vibratory end of the reed 1. Moreover, due to their construction lateral or transverse movement of coil C with respect to the reed 1 is prevented since portions 13 of members M, respectively, engage the ends of pole piece extensions 8 and the offset portions 10=L constitute shoulders disposed between the pole piece extensions 9. By utilizing the structure just described, lateral movement in either direction of both ends of coil C with respect to reed lis revented.

T e coil C may have its terminals 16, 1G connected to binding posts 17, 17a mounted in spaced relation on a member or plate 18 preferably held in place on a yoke or frame A by the aforesaid bolt or screw 5. Member 18 may be formed of suitable insulating material, as a phenol condensation product or hard rubber, but preferably comprises a fabric, as linen or canvas impregnated in a phenol condensation product. 1

As hereinbefore described, the reed l is clamped between the yokes A, A by the bolt or screw 3. Between this screw and the coil C and preferably extending through ears 19 of okes A, A are the members or screws 20 an 21, each of which at its end engages an opposite face of the reed 1. Accordingly', only that portion of said reed to the left of the screws 20 and 21, Figs. 1, 3 and 6, partakes of pivotal movement. Aside from thus determining by their position the length' of the pivotal action of reed 1, the screws 20, 21 have the added function that by adjustment thereof, the reed may be adjusted with respect to the coil C to vary the dimensions of the air ap between its free end and the adjacent aces of pole extensions 8.

The yokes or frames A, A are preferably permanently magnetized, having poles of opllU posite signs at opposite sides ,thereof'adjacent or coinciding with the regions wherein are attached the pole pieces "I?.

Extending laterally from the reed 1 is the member or bar 22, to which is secured the air-vibrating member, diaphragm or tympanum T.

Member 22 may besecured to reed 1 in any suitable manner, preferably, however, as illustrated by riveting a block 23 to the reed and then riveting the block and member 22 to each other.

Likewise", the diaphragm T may be secured to the member 22 in any suitable manner. An example of a satisfactory type of construction, when the diaphragm T is conical, is illustrated in Fig. 6, wherein the apex of the cone is provided with a circular opening faced by the headed or turned portion of a conical member 24 of suitable durable material, as aluminum or soft steel, disposed exteriorly upon the diaphragm T. Disposed interiorly thereof is the conical facing washer or member 25, preferably of hard steel or the like. As shown, the inner portion of member 24 is turned or headed and encompasses the adjacent edges of the diaphragm T and member Resting on the exposed face of the member 25 are the angularly disposed portions of a supporting member or bracket 26 of steel or other rigid material comprising two legs which converge to form a pocket receiving the end of member 22. Passing through aligned perforations inithe pocketed portion K of bracket 26 and the end of member 22 is a bolt or the like 27.

The angular portions ofbracket 26, and

members 24 and 25 may be rigidly united with.

the diaphragm T by utilizing a plurality of rivets or the like 28, each headed on opposite sides of the diaphragm.

As described in my co-pending application, Serial No. 155,159, filed Dec. 16, 1926. the diaphragm or tympanum T should be of relatively large diameter, preferably upwards of six inches, and for both axial and transverse vibration is, unrestricted throughout and free to vibrate at its periphery at the frequency and with the amplitude of vibrations transmitted through the cone from its axis or center, whereat only it is secured or fixed to and comprehended inthe vbra- 'tory system comprising in additlon the vibratory reed 1.

Under such conditions, a feature of my invention resides in the interposition of a flexible connecting-member between the vibratory reed or armature and the cone. Referring to Fig. 6, the pivotal movement of reed 1 imparts to the end of member 22 a to-and-fro movement in a plane extending at right angles longitudinally of the yokes A, A. Should the connection between the vibratory armature and cone be non-flexible,

auch, for example, as is constituted by the rigid pin or bar of the prior art, the cone is given a transverse bodily to-and-fro movement with resultant distorted or imperfect sound reproduction.

A feature of my invention resides `in the interposition of a flexible, rather than a noniexible, member between the reed and cone. Such, for example, as the member 22 which is constructed of spring steel, phos hor bronze, or the like. Due to its flexibility, this member bends or fiexes in a plane extending at right angles longitudinally of the yokes A, A and as 'a result, due to the inertia of the cone, little or no transverse bodily movement is imparted thereto.

Where, however, the cone is unrestrained throughout and free to vibrate at its periphery as described above, the aforesaid member 22 constitutes the sole support therefor, and, hence. should be relatively non-flexible in the direction coinciding with the gravitational plane of the cone so as to carry the weight without flexing or bending. By way of example, the member 22 is illustrated as of substantially greater breadth than thickness and, hence, the aforesaid result may be attainedby so suspendin the cone that the weight is carried in the lirection of breadth rather than width.

To thus render the member 22 non-flexible in one direction does not result disadvantageously, because the vibration of reed 1 does not impart a to-and-fro movement to' the end of member 22 in the direction in which the weight of the cone is carried.

As described in my aforesaid application, Serial No. 155,159 filed Dec. 16, 1926, the herein described magnetic structure having the diaphragm T suspended therefrom may be attached to a casing F, preferably by utilizing the same screws 6 that hold the pole pieces 7 with the yokes A, A. When the frame is constructed of magnetic material, the screws 6 should be of suitable non-magnetic material, as brass. In the event that casing F is constructed of non-magnetic material, the screws 6 may be of magnetic material, if desired.

The aforesaid pole extensions 9 constitute. in effect, a path shunting the path between pole extensions 8 for the magnetic flux induced in thereed 1; Where the extensions 9 are brought into overlying relation with respect to the reed 1, thereby providing two sets of' pole pieces cooperating therewith, it has been found that distortion is introduced into the sound-reproducing system. This condition probably arises due to the fact that the reed is pivotally mounted and, hence, due to the different lengths of the air gaps at the sets of pole pieces spaced unequally from the pivot, the reed, in different regions thereof, is effected by different tractive efforts. By eliminating the tractive effect of pole pieces 9, the reed is attracted and repelled in but one region, thereby rolnoting the faithfulness of sound repro uction.

It is evident that the extensions 9 could be kept in overlying relation to the reed if located at a substantially non-vibratilepart of the reed such as its fixed portion, but 1 prefer the simpler construction shown.

The pole piece extensions 9 may be brought into such spaced relation With respect to the reed 1 as may be suitable or desirable. Merely by Way of example it may be stated that excellent results have been obtained when the gap between each pole extension 9 and the reeld l is of the order of 0.004 or 0.005 of an mc lt shallbe understood that the magnetic system herein disclosed may be utilized to actuate a disphragm of any 'desired character, as for example one which has its periphery restrained from vibration. Further, the magnetic system herein disclosed may be utilized With other types of loud speaking tele- -sirable transverse vibration occurs.

phonic apparatus, as, 'for example, in lieu of the magnetic systems disclosed in the prior application to Kent7 Serial No. 32,875, liled May 26, 1925; Greswold, Ser-iai No. 65,076, iled'Oct. 27, 1925; or to myself and Richter, Serial No. 41,031, tiled July 2, 1925.

It shall also be understood that the conesupportin member, as one having the function and c aracter of the member 22 herein disclosed, may be beneficially utilized, when the actuating reed or armature therefor is pivotally or oscillatorily mounted, with any diaphragm or tympanum which is sufficiently unrestrained from free vibration that unde- Partien larly, a member of the character oit the member 22 herein disclosed, either with or without the associated magnetic system, may be associated with the diaphragms disclosed in the aforesaid applications to Kent, Greswold, and to in 'self and Richter.

, Instea of utilizing a single coil traversed by sound-representing current and surrounding the vibratile armature bar as hereinbefore described, I may utilize construction of the character illustrated in Fig. 10, or equivalent, wherein each pole piece extension 8 is shown as having disposed thereona coil C2 so connected that when one is helping the permanent magnet fiux, the other is opposing it. Obviously, with the construction disclosed in Fig. 1,0, there may be utilized a single coii C2 on but one pole piece extension, if found desirable. Moreover, instead of disposing the coils C2 on the pole piece extensions 8, either or both of the pole piece extensions 9 may have a coil C2 disposed thereon. @r a coil C2 maybe disposed on a pole piece extension 9 and another coil C2 on a pole pieceextension 8; or a single coil C2 may be disposed on the pole piece extensions 8, 9 of a single pole piece 7.

What I claim is: 1'. A telephone magnet system comprising ermanently magnetized frames, pole pieces t erefor extending from opposite sides of said frames, a flexible armature bar disposed between said frames, and means for securing said frames and armature bar in assembled relation as a unitary structure.

2. A telephone magnet system comprising spaced Eermanently magnetized frames, pole pieces t erefor extendin from opposite sides of said frames, a vibratile armature bar secured adjacent its one end to said magnet frames and having its free end disposed ad- 'acent said pole pieces, and a member carried y one of said frames and enacting with said armature bar in a region removed from said one end thereof.

3. A telephone magnet system comprising spaced permanently magnetized frames, pole pieces therefor extending from opposite sides of said frames, a vibratile armature bar secured adjacent its one end to said magnet frames and having its free end disposed adjacent said pole pieces, and members carried, respectively, by said frames 'and extending -toward each other into contact with opposite sides of said armature bar in a region removed from said one end thereof.

4. A telephone magnet system comprising spaced ermanently magnetized frames, pole pieces therefor extending from opposite sides oi said frames, a vibratile armature bar secured adjacent its one end to said magnet tramesand having its tree end disposed adjacent said pole pieces, and adjusting screws carried, respectively, by said frames and extending toward each other into contact with opposite sides of said armature har in a region removed from said one end thereof.

5. .A 'telephone magnet system comprising Aa mavnet trame a-'vibratile armature bar secured adjacent its one end to said frame, and hiturcated pole pieces forming pole piece extensions extendinn toward each other from opposite sides of said frame, one pair oi said extensions overlying each other in spaced relation and embracing a Lfree part of said armature bar, and another pair of said ertensions extending toward each other throughout their length in substantialiy a common plane and terminating closely adjacent said armature bar.

6. A telephone magnet system comprising spaced permanently magnetized frames deiining a substantially rectangular opening, a vibratile armature ar secured adjacent its' one end between said frames and having its :tree end extending into said opening, and biiurcated pole leces forming pole piece extensions extending toward each other intr. said opening trom opposite sides of seid rames,`the pair of said extensions most removed rom said one end of said armature overlying each other in spaced reiation and each other from opposite sides of said frame,

a winding vtraversed by sound-representing current, a vibratile armature bar coacting with a pair of said pole piece extensions and extending axially through said windingy'and means comprising a plurality of duplicate non-magneticv members supported by said pole piece extensions and upon which said winding is disposed. y

8. A telephone magnet system comprising a magnet frame, bifurcated pole pieces-forming pole piece extensions extendin toward each other from opposite sides of said frame, a winding traversed by sound-representing current, a vibratile armature bar coacting with a pair of said pole piece extensions and extending axially through said Winding, means comprising ya plurality of duplicate non-magnetic members supported by said pole piece extensionsand upon which said winding is disposed, said members being constructed and arranged to prevent transverse movement of said Winding with respect to said armature bar.

9. A telephone magnet system comprising spaced permanently magnetized frames deining a substantially rectangular opening,a

vibratile armature bar secured adjacent its'A one end between said frames and having its free end extending into said opening, bifurcated pole pieces forming pole piece extensions extending'toward each other into said opening from opposite sides of said frame, one pair of said extensions overlying each other in spaced relation and receiving said free end of said armature bar, and another pair oi said extensions extending toward each other throughout their length in sub stantially a common plane, a Winding through which said armature bar axially extends, and members maintained in spaced position by said extensions to support and position said Winding. ,i

10. A telephone magnet system comprising` spaced permanent-ly magnetized frames delining a substantially rectangular opening, -a vibratile armature bar secured adjacent its one end between said frames and having its free end extending into said opening,bifur cated pole piecesl forming pole piece extensions extending toward each other intosaid opening from opposite sides of said frame, one pair of said extensions overlying each other in spaced relation and receiving said free end of said armature bar, and another pair of said extensions in close relation to said armature bar and in 'substantially a common plane, a Winding through which said armature bar axially extends, and means for supporting and preventing transverse movement of said winding with respect to said armature bar comprising a plurality of duplicate members, each of which comprises a pocket receiving a pole piece extension of said first-named pair and a shoulder disposed between the pole piece extensions of said secondnamed pair.

11. A telephone magnet system comprising spaced permanently magnetized frames deining a substantiall rectangular opening, a vibratile armature liar secured adjacent its .one end between said frames and having its free end extending into said opening, bifurcated pole pieces forming pole piece extensions extending toward each other into said opening from opposite sides of said frame, one pair of said extensions overlying each other in spared relation and receiving Said free end of said armature bar, and another pair of said extensions extending toward each other throughout their length in substantially a common plane and in close'relat-ion to said armature bar, a winding through which said armature bar axially extends, and means for supporting and preventing transverse movement of said Winding with respect to said armature bar comprising a plurality of duplicate members, each of which comprises a pocket receiving a pole piece extension of said first-named pair, a shoulder disposed between the pole pieceextensions of said second-named pair, and an angular portion engaging the magnet system comprising a vibratile member, a diaphragm of large area and means for securing said diaphragm to A.said vibratile member comprising a member having substantially different iexibility in one direction than in another.

13. A loud speakingl telephone having a magnet system comprising a vibratile member, a conicaldiaphragm of large area, and means for securing said diaphragm solely adjacent its apex to said vibratile member coinprising a member having substantially greater fiexibility in one direction than 1n another.

14. A loud speaking telephone having a magnet system comprising a vibrat'ile inember, a diaphragm of large area whose periphery is entirely free of restraint, and means for securing said diaphragm to said vibratlle member comprising a member having substantially different flexibility in one direction than in another.

15. A loud speaking telephonel having a magnet system comprising an elongated vibratile member, a diaphragm of large area Whose periphery is entirely free of restraint, and means for vsecuring said diaphragm to said vibratle member comprising a member lla-ving substantial flexibility only in a direction coinciding with the longitudinal axis of said vibratilemember.

16. A loud speaking telephone having a magnet system comprising a vibratile armature, a diaphragm of large area, and a member extending laterally from said armature constituting the sole support for said diaphragm and substantially non-flexible in the gravitational plane thereof and of relatively great flexibility in a direction substantially at right angles to said plane.

17. A. loud speaking telephone having .a magnet system comprising a vibratile armature, a dia hragm of large area, and a member exten ing laterally from said armature of substantially greater breadth than thickness and constituting the sole support for said diaphragm, the breadth of said member coinciding with the gravitational plane of said diaphragm.

18. A. telephone magnet system comprising a magnet frame, bifurcated pole pieces forming pole pieceextensions extending toward eachother from opposite sides of said frame, one pair of said extensions overlying each other in spaced relation, and another pair of said extensions extending toward each other' throughout their length in substantially a common plane, a vibratile armature bar secured to said frame and in part received between said iirst named extensions and closely approached by said second named extensions, and a Winding traversed by sound-representing current for vibrating said armature bar.

19. A. telephone magnet system comprising a magnet frame, a vibratile armature bar rigidly secured adjacent its one end to said frame, and bifurcated pole pieces forming pole piece extensions extending toward each other from opposite sides of said iframe, the pair of said extensions most removed from said one end of said armature overlying each other in spaced relation and receiving said armature bar at or adjacent its free end, another pair of said extensions extending toward each other throughout their length in substantially a common plane to` regions closely adjacent said armature bar, and a winding traversed by sound-representing current through which said armature bar extends.

20. A telephone magnet system comprising a magnet structure, an armature bar vibrating in one plane only, bifurcated pole pieces extending from both poles of said magnet structure into close relation with freely vibratile portions of said armature bar, a pair of pole piece extensions of op osite polarity situated on opposite sides o? said armature bar and in its lane of vibration, the other opposing pair ci) pole piece extensions also situated on opposite sides of said armature bar but in a plane at right angles to its plane of vibration, and a Winding traversed by sound-representing current 'surrounding any or all of said pole piece extensions or that portion of the armature bar which lies between the two pairs of pole piece extensions.

, 21. A telephone magnet system comprising a magnet structure, an armature bar vibrating in one plane only, pole pieces extending from both poles of said magnet structure and each divided into two ole piece extensions, one pair of said pole piece extensions of opposite polarity situate on oppositeI sides of said armature bar and in parallel close relation to freely vib'ratile faces thereof, the second pair of pole piece extensions of opposite polarity situate in close relation to nonvibratifle surfaces of said armature bar, and a Winding traversed bysound-representing current surrounding any or all of said pole piece extensions or that portion of said armature bar which lies between the one pair and the second pair of said pole piece extensions.

22. A loud speaking telephone having a magnet system comprising a vibratile member, a conical'diaphragm of large area, a member passing freely through said conical diaphragm substantially' at the apex thereof, out of contact therewith, and secured to said vibratile member on the`convex side of said conical diaphragm, and means to attach said conical diaphragm to said member on the concave side thereof.

23. A loud speaking telephone comprising a large diaphragm capable of axial and transverse vibration, a magnet system, structure co-operating therewith and movable in accordance with current variations of audio frequency, and a member connecting said diaphragm to said structure having substantially gr'eaterlexibility in one direction than in another to eeet substantially solely axial vibration of said diaphragm.

24. A loud speaking telephone comprising a large diaphagm capable of axial and transverse vibration, an actuating member therefor having components of motion axially and transversely of said diaphragm, and a member connecting said diaphragm to said actuating member having substantially greater lexibility in one direction than in another to transmit to said diaphragm substantially solely said axial component of movement of said actuating member.

25. A loud speaking telephone comprising a large diaphragm capable of axial and transverse vibration, a magnet system including an armature having components of motion axially and transversely of said diaphragm,

`and a fie'xible member of Width substantially exceeding its thickness connecting said diaphragm to said armature to efl'ect substantially solely axial vibratile of said diaphragm.

26. A loud speaking telephone having a magnet system comprising structure comperliti ating therewith and movable in accordance with current .variations -o audio-frequency, a conical diaphragm of llarge area and capable of axial and transverse Vibration, a member passing through said cone substantially at the apex thereof secured to said structure and having substantially greater flexibility in one direction than in another to transmit substantially solely said axial component of movement of said structure, and means connecting said member to the concave side of said diaphragm.

RUSSELL T. KINGSFORD.

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