USRE23327E - Pickup with reed of magnetic - Google Patents

Description

Jan. 16, 1951 D. J. BAKER Re. 23,327

PICKUP WITH REED OF MAGNETIC MATERIAL origial Filed March 12, 1945 2 Sheets-Sheet 'l DONALD q. BAKER Jan. 16, 1951 D. J. BAKER Re. 23,327

PICKUP WITH REED OF MAGNETIC MATERIAL Original Filed March 12, 1945 2 Sheets-Sheet 2 FIG. '73; FIG 7 12 Op? P5 FIG 9. L e Q \w\\` FIG lo.

A5 wuwvto'r,

V DONALD J. BAKER 5o 1 10,060 Mm FIGll. 5

Ressued Jan. 16, 1951 PICKUP WITH REED OF MAGNETIC MATERIAL Donald J. Baker, Los Angeles, lCalif.

Original No. 2,422,817, dated June 24, 1947, Serial No. 532,332, March 12, 1945. Application for reissue .ione 22, 195i), Serial No. 169,766

si reims. (ci. ire-icuii) Matter enclosed in heavy brackets fi appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue This invention relates to pickup head constructions useiui in phonographs and other sound reproducing apparatus.

One general object of the invention is to greatly simplify the construction of a pickup head over constructions now in common use.

Another general object is to reduce the total Weight of the pickup head, and also reduce the mass of the vibrating parts.

A speciiic object of the invention is to eliminate the usual pivot or trunnion bearings for supporting the vibrating stylus. In prior constructions it is common to mount the vibrating stylus for vibration about a substantially horizontal axis located in a vertical plane which is tangent to the groove being engaged by the needle, the stylus being arranged in a generally vertical position with its axis in line with the axis of the needle. Such arrangements involve the use of pivot bearings ior supporting the trunnions which extend to the front and rear ci the stylus. Such bearings are a source of many diiliculties -lor which various solutions have been offered with varying degrees of success. One common arrangement involves the use of rubber bearings for the trunnions for the purpose of eliminating disturbing noises caused by the bearings. The main objection to such bearings is thaJ the rubber deteriorates with age and becomes hard and inflexible. Cracks develop in the rubber and the bearings become noisy. Another serious objection to any rubber-pivoted armature suspension is the fact that the armature has an up and down motion known technically as vertical response, and this is very detrimental to this type of pickup, because it introduces distortion. This is the reason normal position. A pickup coil may be carried on or surround a fixed part of the reed or it may be carried on or surround the movable exible part of the reed. The iront end of the reed, including the needle, is arranged to vibrate between the poles of a permanent magnet which is preferably mounted in a substantially vertical plane at right angles to the plane of the reed. Vibration of the reed laterally causes magnetic ux to be established in the reed in `-one direction or the other depending upon whether the reed is near one pole or the other of the magnet.

My invention also involves the novel structure for damping the vibrating part of the reed to eliminate resonance effects.

My invention is illustrated in the accompanying drawing in which:

Figure l is a plan view of one form of my pickup head showing the cover removed.

Figure 2 is anelevational view of Figure 1 showing the casing of the pickup head in longitudinal section.

Figure 3 is a sectional view of Figure 2 taken along the line 3 3 except that certain elements are shown in elevation.

Figure 4 is a perspective view showing the end of the needle-supporting reed and illustrating the f ci the arrangement shown in Figures 1 to 3.

Why special needles with the bent shank and the of the pickup head is permanently secured to the free end oi a thin blade-like reed element or armature mounted in a vertical plane which is tangent to the groove being engaged by the nee--y die, and the axis of the reed extends horizontally and parallel with the surface of the record, the rear end being xed or clamped in a suitable base support. At least a portion of the reed at the free end thereof is made thin and flexible so that the needle may vibrate laterally or at right angles to the plane of the reed while the axis of the needle remains substantially parallel to its Figures 7 to 10 illustrate a modified construction involving a hum-bucking coil. Figure 7 is a longitudinal, sectional View; Figure 8 is a face View of the upper half of Figure '7; Figure 9 is a face View of the lower half of Figure 7; Figures 7F and 7G are sectional views of Figure 7 taken along the lines F-F and G-G, respectively; and Figure 10 is a perspective View of the lower half of Figure 7.

Figure l1 is a typical response curve for my pickupunit,

Referring to the drawing, I indicates the end of a tone arm which supports the pickup head. The pickup head has a casing 2 formed of nonrnagnetic material such as molded plastic. The rear part of the casing is provided with a shank portion 2a having a reduced section which extends into the open end of the tone'arm l and is secured to the tone arm-by a lsuitable screw 3.

4Thecasingalso, has a removable section or cover is" formed by cutting down the end of 'the' reed- 2b which is secured to the main section by suitable screws 4a. and 4b.

At the front of the casing 2 a permanent magnetS is amounted in a verticalplanetransversely of the axis ofthe pickup head, the magnet being mounted in inverted position so that the gap between the poles of the magnet includes the median plane offthe'pickup'fhead which is normally tangent to the groove ofthe record beingr engaged by the needle. The mag- 10 net 5 is mounted in a socket formed by vvertical walls 2c, 2c arranged on Opposite sidesof the magnet and preferably formed integral with the base of the casing. Y

In the rear of the casing 2 a block of ybrass 5 l5 or other suitable metal is secured inposition --.within-.the casing by suitable fastening-means represented byv screw 1 and is-provided with. a forwardly extending portion at the lower part thereof which serves to support the rear end of 20 ".frazhorizontal-reed 8, the free lend' `of` whichfextends v'-fintol-thergap between the'poles .of the 'magnet 5 I:asshownin Figure 2. The rear end' ofthe reed eenters'awertical slot formed inthe forwardly extending lower portion of block E and is sol-.i125

shank of the fneedlel'is bent to assume a-'horizontalfpositionwhile'in use, land the.- horizontal portion of the shankisslotted by asawcut 01135vv .otherwise tovrecei-vethe-thin-end-of thereedS,

and the two parts are soldered/or-.otherwise secured together. The needle extends downwardly at an angley inclinedtothe surface of the VVrecord inl-the usual rmanner.V passing throughlaholefm formed fin lthe bottom wall of.. the ,easingv 2. A

Washer or gasket Il] preferably formed of a thin ..sheet .ofV syntheticrubber is. sealed within the Y:.-needle opening .and surrounds theneedle to seal the casing 2 against entranceof dust and mag- 45 ....netic. particles which-mightirnpair the operar...tionfoflthefpickup head. .It must beunderstood that this Very.thin.rubber, which is only .001 to ...-(lzfthiclr,` in-=no,v.ray. actsas a dampening agent.

Preferably,!the.,needle Elv is ilattened in the plane. 50

. of-.the-.air gap so as to prevent undue interference with the poles of the. magnet andto permit Y ..the.useof a narrow airrgap.

The. reed 8 maybe formed of a solid piece of beformed offa laminated structure as shown in` Eigure 4. In this arrangement, the reed is formed of threestrips of magnetic material joined together in any suitable' manner as by spot welding `or soldering. The middle strip'which is longer. so,

than the'two side strips carries the needle 9, and, "as shown in the drawing, this strip is muchthin- "ner than the-needle itself. I have foundl that a silicon steel strip having a 'thickness of 0.003 inch 'gives satisfactory'results. The two'outside'strips: 8a and 8b may be formed of the same orgreater :thickness x I have secured good reSultsby form- ;.c-.ing theo-utside pieces of va strip having .athickrsness-.ofcll inch,.all three strips being T3@ of `an inch-wide. .With this construction, the threeionly. portion oftherced is substantially rigid, but A...therforward'..portion is flexible and -the .end of the reedjis'free to. iLeX vor vibrate about ak vertical axis. The reed S may be formed of a'solid` piece .of magnetic material'where the flexibleV end'partV be formed separately from these walls. .damping material la may bevforrned of sinall to a narrow section. Als-o, the entire reed may be formed of a single flexible strip ci the same thickness throughout, as will appear hereinafter.

.The rear portion of the reed between the inagnet 5 and the block 6 is wound with a sleeve of suitable insulating material i l on which is wound a pickup coil i2. The ends of the coil l2 are connected to suitable terminals i2a and lib 'which are 'mounted within insulating sleeves passing through holes formed in block t, and the `rear ends'oi these terminals are connected by suitable conductors with amplifying apparatus not shown.

For the purpose of damping out resonance effects in the Vibrating portion of the reed, I provide damping material in contact with opposite sides of the thin part of the reed as shown at i3 in Figure `l. The damping is designed to use a minimum amount of damping material, because the less the mass of this Ina- "terial,;.the less mass the needle has to move. This -dangling'material is inserted between the vibrating reed and a pair oi fixed stops i@ mounted on the .base of the casing?, and these stops'rnay be an'integral part of the vertical walls 2c and 2c forming the socket for magnet 5, or they may The blocks of suitable material inserted between the "reed and the'stops i4, but I prefer to form these damping elements by applying a srnall drop of `liquid substance between eachy side of the thin 'material' which I have found most suitable for ythisv purpose is a commercial product of synthetic resin in liquid form.

Inl-the operation of the arrangement illustrated lin Figures l to 3, the needleV is `vibrated laterally by thevgroove in a lateral cut record,

andthe flexible end of the reed il is flexed by the needle as it moves from side to side. This action is: shown in Figure 4-where the normal. position ofl the needle 9 is shown in solid lines and the deiiected position isshown in dotted lines, but the amount of deflection has been greatly exaggerated. The deflection of the end of the reed is -fsuch that the needle remains parallel. to its original. position, and this is more clearly illustrated in FigureAa whichis a view taken directlyin front of the needle and shows the normal position ..magnet1c rnater1al suchas .silicon steel, or 1t may.. 55,

.of the needle in solid lines and the deiiected position. in dotted lines. lt is understoodthat this parallel motion is only between narrow limits at the greatest amplitude. In the record itself it does not travel over .092 of an inch.,but this parallel Vtype of motion which I employ is not parallel beyond .003 of an inch from center. ln other words, the parallel motion from one extreme to the other is about .Q15 of an inch.

. Fromthen on the reed starts to lie over more as mfiv-v greater motionis attempted. From Figure 4a r itlwill be understood that the anis of the needle whendeflected to either yside of its normal posiy.tion remains substantially parallel with its original position. This is in contrast with. the angular "shifting of the needle in prior arrangements where the stylus is `mounted on trunnions to vi The action of such showing one extreme position of the needle in solid lines and the opposite position of the needle in dotted lines. It is clear that the axis of the needle swings about the pivot point P and the point of the needle engages the vgroove of the record with adifierent angular relation for different positions of the needle. The advantage of my type of stylus and needle mounting is that it maintains a co-nstant angular relation between the needle and the surface of the record and thereby eliminates the scratch and wear on the record due to the varying angular position of the needle with respect to the groove in the old arrangement. Also, in my construction, the point of the needle travels parallel to the face of the record whereas in Figure it travels in an arc with respect to the face of the record.

In Figures 1 to 3, it will be understood that the section of the reed carrying the pickup coil I2 remains substantially stationary and only the thin front end of the reed is vibrated. By this construction the entire mass of the movable part can be reduced to as low as 0.1 gram, and the response curve for this type of pickup remains substantially iiat up to frequencies in excess of 10,000 cycles per second and approaching 15,000 cycles per second.

It will be understood that the end of the reed projecting into the air gap of the magnet 5, and the needle carried by the reed, are normally positioned substantially at the center of the air gap, and no substantial amount of magnetic flux is carried by the portion of the reed Surrounded by the coil I2. As soon as the needle is moved from the center of the air gap towards one of the poles, magnetic flux will be established in that part of the reed which is surrounded by the coil I2 in one direction depending upon which pole is being approached by the needle. If the needle moves in the opposite direction from its normal position, the magnetic flux established in coil I2 will be in the opposite direction; and the continuous vibration of the needle to opposite sides of its normal position will cause an alternating voltage to be induced in coil i2 having a frequency" or frequencies corresponding to the rates of vibration of the needle. Thus, reed 8 constitutes a magnetic armature fo-r the pickup.

Where the entire length of the reed is formed of a thin .flexible blade, and the coil is carried by the flexible part of the blade, the over-all length of the blade may be materially shortened and the pickup coil would be shortened correspondingly, such an arrangement being shown in Figure 6. This figure also shows how the needle 9 may be mounted on the reed by simply slotting the straight shank of the needle at the end for receiving the end of the reed and soldering the two elements together. In this way a shorter needle may be used and the vibrating mass reduced accordingly. The damping material bonds or blocks are applied to opposite sides of the reed in the same manner as described above for Figures 1 and 2, and the point of application of these damping elements is indicated by the dotted circle I3 in Figure 6. Figure 6a is a front view of the reed of Figure 6 showing how the damping connections or bonds are applied between the reed and the stops i4. Preferably the coil i2 is carried by the magnetic reed and vibrates with it, although the coil could be wound on an insulating sleeve which surrounds the reed with enough clearance to permit vibration of the reed Without moving the coil.

, In an actual model V constructed according. t0

Figure 6 the reed 8 was formed of a strip of silicon steel having a thickness of 0.008 inch, a width of -e of an inch and the length of the flexible portion extending out from the block 6 was only Tse of an inch. The coil l2 was formed' y needle-supporting reed relatively short and thin so that the resonant frequency of f the vibrating part of the stylus will be in the higher frequen cies of the audio range or above this range. If the natural frequency of the reed and the attached needle is above the essential audio range, for example, if the natural frequency is 20,000

` cycles per second, then it will not be necessary to provide any damping of the reed since the frequency response over the audio range will be substantially constant. By properly selecting the resonant frequency of the reed and using the proper amount of damping, it is possible to obtain almost any desired response characteristic. I have found that a reed which has a natural period of Vibrationraround 10,000 to 12,000 cycles per second gives good response at the higher audio frequencies and yet provides extremely llow lenience or compliance, and requires very little damping to correct for distortion due to 'resonance. A typical response curve for a pickup designed according to my invention is illustrated in Figure 11.

The preferred position of the magnet 5 is in a vertical plane as shown in Figure 2, but the magnet could be arranged in av horizontal plane or in any intermediate plane. For example, in the case of the arrangement illustrated in Figure 6, the yoke of the magnet might extend around to the back of the block 6.

The novel construction of the pickup head as described above and illustrated in Figures 1, 2, 3 and 6 involves the following novel features and advantages;

1. The axis of the needle remains parallel to its normal position during vibrationand at right angles laterally to the surface of the record. This reduces the amount of needle scratch and the amount of wear on the record by the needle.

2. The thin reed mounting of the needle provides extremely great compliance or lenience of the mounting and there is very little stiffness to be overcome in vibrating the needle. This allows low tracking pressures on the needle, as low as 2 grams.

3. The needle-supporting reed is mounted with its longitudinal axis horizontal and parallel with the surface of the record and substantially at right angles to the axis of the needle. The iiexing of the reed causes the needle to move about a substantially vertical axis and the point of the needle travels parallel with the surface of the record. This is in contrast to prior arrangements where the stylus vibrates about a substantially `horizontal axis and the point of the needle travels in an arc with respect to the surface of therecord.

fl. The construction is simple in arrangement and may be easily manufactured.

5. The mass of the entire system is extremely low, thereby eliminating unnecessary wear of the needle on the record, and vice versa.

6, The mass of the vibrating parts is very low,

" resulting :sin vafs-nat response characteristicroyer a wldexfrequencyirange.

'i 'Z'.The .arrangement :of :the z needle-supporting erreedf-irrzaf vertical-plane provides; greater rugged- Acurs in: prior artistructures iusing' r'ubberf pivot bearings.

.8. Ther'response;'chara'cteristici-may be easily controlled .1 by .-.1providing. differentry amounts of Lfda-mping. on :the vv needleesupporting freed.

'9LfiThe pickupheaddoes not Ainvolve the use ofk i materialsffwhich'i are:k adverselyxaffected byiiexutreme conditions-*fot temperature` and humidity.

'10; By'the-use of'short, thinsreeds. having a naturalrate 'of vibrationy in the upper frequencies.Y

:fof-the. audio range," the 1response:characteristic fior-the high audioy frequenciesizis :improved FIn' the arrangement of Figures 7 to10.the'cas ling Lis divided alongja horizontalxiplane'- and is 'liformed of-a lower :section 2andranauppersecion 2". s"Par-ts serving-the same. or similar functionsfas corresponding parts in Figures 1 to 3 are Vindicated by -like :reference numerals. The'` per- 'Ymanenthmagnet 5 is Imountedfin a suitablesocket formed. inthe front end of the lower section 2*,1

andl the needle-supporting reed 8 f. carrying `the f pickup coil I2 isalso mounted in the'lower section -"l:ut is supported in adiiierentmanner from Fig- -ures l `and 2. vThe reed with the pickup coil wound -thereon is supported within slots formed'iin Vis-f.

coloid blocks I5 positioned at each end and at #thecenter of the coil I2. 2 The coilis tightly wound around-a-cellophanefsleeve wrapped around the reed; and lthe blocks-I5 press rrnly against the sides Y'of the 'coil to hold the reed andk coil Yassem-vr bly in proper-position. If there is any looseness f between the Vcoil and the block, orvbetween f the blocks and the casing, these elements A-may be Acemented together by a suitable 'fcement. Figure 7G is Iasectional viewof the-1 lreedand coil Aassembly taken through the center block. The Viscoloid blocks I5 serve to damp outvany resonance effect in'therear portion ofthe reed carrying the lpickup coil. These blocks 'mayV be formed of -other-v dampingmaterial l than" Viscoloid.

The forward flexible end of the reed ,8 is suit- 'ably damped by a pair of blocks of damping material I3 mounted-.on opposite sides ottherreed vand having contact therewith, see: Figure 9.

One end oi pickup coil- I2` is connected toa terminal 12a mounted in the rearend of section 2', and the other end of the coill is connected to a v-lsecond terminal I2b. One of the leads L for the Ypickup unit is connected to terminal IZa and 'the other leadzis connected to a terminal I2c AVVmounted in the same cavity with terminals I'Za and I2b. These two leads `are `admitted tothe terminal cavity through half-round slotsformed ineach section of the casing.

VrIn the upper section' 2-l of the pickup casing a hum-bucking coil AI2is-arrar1ged parallel with H'and immediately above thepickup coil I2. This coil has a magnetic core 8y built substantially like the .needle-carrying reed 8, and the coil is Wound on an insulating sleeve I I carried bythe core' 8. 'The hum-bucking coil is positioned within a longif tudinal slot formed in the face of the uppercasing section 2 and v'issecured'in positionfbyfsuitfiable' cementi-ngmaterial shown atYV I 1. 1 One end ftioned inaqcavityfinthe 'rearl end of thefcasing section 2, and thev other end of the coilis cons nected to-terminal I2c. Terminals I2b' and I2c `are arranged-'toV be` in. axial alignment with terminals .I 2b and 12e, respectively, and all fouriof these terminals are formed `with an axial bore.

When'the'two-halves of the casing are placed in matchingrelation, a conducting iwirexor pin -I'Bixis'inserted .infthe aligned bores of the two pairs .of terminals. :for the. purpose of connecting ithe upperandllower vterminals. together. -.This sarrangementis'fclearly shown for .terminals I2C nectingiwire I8 may'. be soldered. to :the-respective-terminals aslshown at .I Ba and Ib in Figure 7F. By the` :arrangement just described, vthe two rc'oils` l2f-andll2' are. connected in series .between "the leads L ofthe .pickup unit,l and itis .important 'that the-.ends'of the two feoilszbe 'connected to vthey properterminals in order that the twov coils 1 --are 'connected in opposing v relation; .that the two coils should be so connected `that ii they-were energizedfby direct current, one coil wouldY produce-a north lpole atthe frontend while the other coil wouldv produce asouth pole at the `'same end.

With this arrangement, the coili' servesrto'cancel out or neutralize anyy Vdisturbing voltagerwhich might be induced in ooit-'I2 by an l.external magneticlfield-Lacting on the coil or on'reedf E. By arranging the coil I2 parallel Wit-h .and close to the coil I2, any disturbance due to an vexternal fmagnetic field may be substantially neutralized.

3 Such disturbances might come I'irom the field of ibly of the twoA casing sections and holding the y'two sections in properl matching relation, a pilot pin i9- is carried by the frontend of the upper -casingeseotion and is arranged to enter a socket formed in the face ofthe lower section. Thisvpin,

yand the two connecting pins I8. positioned at the Vrear of the unitserve-tohold the two casing sections inproperposition. `The 'two sections are securelyy clamped together oy suitable screws M threadedy into threadedfholesV-'Ze formed in the lower casingsection, the heads ofthe screws being seated in countersunk'holes 2| formed-in the upperY casing-section.

It willbeobvious that the pickupv'constructions described herein may be adapted for use as a recording head by substituting a, recording stylus for thev pickup needle and by supplying. electric signalsto thecoil surrounding the armature. Ac-

cordingly, the appended claims areto be interpreted broadly'as rcovering devices for either re- A'cording `or reproducing electric signals.

I claim: .1. An electrictranslatingdevice comprising, in

a? substantially horizontal position, means for rigidly .supportingone end ofsaid-reed with the other: end thereoffbeing free and positioned withv.tinsaidgairfgap, saidv supporting means serving to preventupwardilexure of said free end but perf .mitting lateral exure thereof, -a stylus secured to and supported entirely by the free end of said :v reed with its` axis `located substantially -in the plane of said reed'andextending substantially at right angles to the axis of said reed,;-and. an electricdcoil surroundings portionnf said ireed.

ease? 2. An electric translating device according to claim 1 wherein said magnet is mounted in a substantially vertical plane transversely of the plane of said reed. Y

3. An electric translating device according to claim 1 wherein said stylus is formed of magnetic needle and the shank thereof is positioned within the air-gap of said magnet.

4. An electric translating device according to claim 1 wherein said coil surrounds a fixed portion of said reed adjacent said supporting means.

5. An electric translating device according to claim 1 wherein said coil is wound upon and carried by a flexing portion of said reed.

6. A stylus mounting for an electric translating device comprising, in combination, a thin, ilexible, relatively broad magnetic reed mounted with its broad face in a vertical plane and its axis in a substantially horizontal position, means for rigidly supporting, one end of said reed with its broad face in a vertical plane to thereby prevent upward flexure of the free end thereof while allowing lateral flexure of the unsupported end, and a stylus supported entirely by said reed near the free end thereof and with its axis located substantially in the plane of said reed and arranged substantially at right angles to the axis of said reed.

'7. A mounting according to claim 6 wherein said stylus is formed of a magnetic needle having the shank thereof slotted for receiving the free end of said reed, said needle being permanently bonded to said reed.

8. A stylus mounting according to claim 6 and including a pair of fixed abutments mounted on opposite sides of a flexing portion of said reed and in spaced relation thereto, and a bonding connection between each of said iixed abutments and said reed, each connection comprising the dried residue of an adhesive resin applied in liquid form between said reed and each abutment.

9. A stylus mounting for an electric translating device comprising, in combination, a thin, flexible magnetic reed, means for rigidly supporting one end of said reed on-edge to permit flexure of the free end thereof about an axis transversely of the length of the reed, and a stylus supported entirely by said reed near the free end thereof with the axis of the stylus lying substantially in the plane of said reed and arranged substantially parallel with the axis of flexure of said reed, said reed and stylus assembly having a natural'period of vibration in the upper audio frequency range.

10. An electric translating device according to claim l wherein said coil surrounds a portion of said reed spaced from said magnet, and including a pair of fixed blocks of damping material engaging opposite sides of said reed at a point between said magnet and said coil.

11. An electric translating device according to claim 1 wherein said stylus is formed of a magnetic needle having the shank thereof slotted for receiving the free end of said reed, at least a portion of said slotted shank being positioned within the air-gap of said magnet.

12. An electric translating device according to claim 1 wherein said stylus is formed of magnetic material and has a horizontally arranged shank portion positioned within the air-gap of said magnet and a tip portion extending downwardly out of said air-gap.

13. A mounting according to claim 6 wherein said stylus is formed of magnetic material and has a straight shank portion arranged coaxially with said reed and a tip portion extending down- 10 c wardly from said shank portion to a point beyond the lower edge of said reed. f

14. A mounting according to claim 6 wherein said stylus comprises a magnetic needle having a straight shank portion and a tip portion extending substantially at right angles to the shank portion, said shank portion and a part of said tip portion being slotted to receive the free end of said reed,-and the two halves of said slotted portions being permanently bonded to opposite sides of said reed with the straight shank portion arranged horizontally and coaxially with said reed.

l5. An electric translating device comprising, in combination, a magnetic structure including a pair of spaced pole pieces providing an air-gap in a vertical plane, an armature comprising an elongated magnetic reed formed of relatively thin strip material, mounting means for supporting said reed with axis in a horizontal position and arranged substantially in the plane of said air-gap, said mounting means comprising a fixed support spaced from said pole pieces for rigidly supporting one end of said reed with the other end thereof being free and positioned adjacent said pole pieces to vary the flux distribution between said pole pieces and said reed when the free end of the reed moves transversely of the plane of said air-gap, the supported end of said reed having its broad face arranged in a vertical plane to provide relatively free lateral ilexure of the reed while resisting upward exure thereof, and a stylus supported entirely by said reed near the free end thereof, with its axis positioned substantially vertically, and a stationary ypickup/coil surrounding a part of said magnetic structure in which the iiux is varied by transverse mov-ement of the free end of said armature.

16. A stylus mounting for an electric translating device comprising, in combination, an elongated, relatively thin, flexible magnetic reed arranged wth its principal axis extending horizontally, means for rigidly supporting one end of said reed with the broad face thereof in a vertical plane to provide a greater degree of flexure of the reed horizontally than vertically, and a stylus supported entirely by said reed near the free end thereof and arranged with its axis substantially in a vertical direction.

17. A stylus mounting for an electric translating device comprising, in combination, an elongated reed-like member arranged with its principal axis extending horizontally, means for rigidly supporting one end of said member, the supported end of said member being relatively thin horizontally and wide vertically to provide a greater degree of fiexure of said member about said supporting means horizontally than vertically, and a stylus supported entirely by said member near the free end thereof and having its axis arranged in substantially a vertical direction.

i5. An electric translating device comprising, in combination, a U magnetic structure have ing a pair of spaced pole pieces having parallel vertical faces providing an air-gap, an armature comprising an elongated magnetic reed formed of relatively thin, strip material, means comprising' a fixed support spaced from said pole pieces for rigidly supporting one end of said reed cdgewise vertically with the longitudinal axis of the reed in a horizontal position and with the other end thereof being free and positioned to swing between said pole faces to vary the fina: distribution between said pole pieces and mounting 23,?, eti

said-reed when the Yfree-end lci the reed movesacross said air-gap, the supportedendoi said reed having its broad face. arrangedl ina` verticalY planeV to provide relatively free lateral flexure of the reed-while resisting upward fleure thereof at its' supported end, and a stylus s upportedentirely by said reed near the free endthereoj with the axisof saidreed positionedsubstantially*vertically', and-a stationary pickup coil surrounding alpart'of the said` magnetic structure embodying said magnet-'and said .reed in* which the 'flux isA vertical "plane to provide a -greater degree Y of l jleure vvofthe reedr horizontally than vertically, and astyljajs supported entirelybyY reed near theffree,endthereof and arranged with its ascissubstantially in a vertical direction, a magnetie structure positioned -,forwardly o!v said reedrand having pole 'faceslaterally spaced on opposite sides of the free end Aoysaid reed, and a base supporting,k saidlnstylus and magnetic structure for movement ofi-the point of-said stylus in the plane of a lateral'cut record,'

20.V A stylus mounting for l an electric translating device/' Y comprising, in combination, an elongated, relatively Athin; flexible magnetic reed arrangednwith Jits principal axis etending horizonta'll'y,l means for.'- rigidly supporting one end of saidvreedlwithfthe broadjace thereof in a vertical plane to1provide a ,greaterk degreey of ilescure of the reed horizontally than vertically, and a stylus v supportedlentirely ,by said reed near the free' end f thereof and', arranged withv its artis substantially in a vertical`dire'ctio-n, magnetic means having polef faces, baseoflinsulating material,y supporting v said magneticmeans, forwardly of said l reed witlisaidpolejaces laterally' spacedon opposite sides otthe freeend Yofjsaid Vfreed, ksaid stylus extending tbeyond, the bottom 'of said 'base in position, orfengage a sound record.

21.'A,styluisV mounting for an electric translating device comprising, in combination, an elongatedmagneti reed-.like member arranged with 'fitsffprincipal axis, extending horizontally, meansvforrigidly supporting only oneend of said member .forjlexu're abouta vertical hinge assis, the, other end .of said member being free, the supportedrendof Asaid member being relatively thin horizontally and. wide vertically to provide a greater. degree of jleiture of said member aboutv saidQsupporting, means horizontally, than, ver.- tically, a styluss'upported entirely .by said ,inembernear-the free en dthereof and having its axis arranged substantially-a vertical direction, a magnetic'structure having pole faces at opposite sides of said free end, and a coil indactively influenced by .motion of said reed-like member.

22.` A stylus mounting according to claim 21 wherein said hinge axis is adiacent the free end of .said member, means for stiening said memn the ksame order as the lengthlloff-said Aihinge 24.- A=stylus mounting vaccording-to' claim '21 f wherein saidV hinge-axis is forwardly fdisposedyion* said member in space relation to thesupported endoj-saidmembeh the length of sa-idwmemfber' forwardly -e j said hinge aais being-short and conducive to a high natura-l frequency o! vibration; the distance from the pointy of saidstylns'to said" member being shortR i and `conducive -j to -Yfreedonie from torsion.

25. A-stylus mounting foran electric translat-l ing device comprising, in combination; a thin, flexible magnetic -reedymeans for-'rigidly supporting one end of said reed on Vedge tapermitfflezture of the freey endthereoabout an axis transversely of the length ofthe reed, v"and-a stylus supported:

entirely by said reednear the free 'endthereoff with theais of the stylus lying substantiallyy thesplane of said reed^andarranged substantially parallelwith'axis of ftexure of said reed; said reed having a hinge aisforward of the supported end 'of the reedgsaid freev end lJorwaroloy said Ahinge axis` being of, small'mass and short" length' whereby ysaidjfreed 'and stylus assembly'f haveharnatural period fof vibration in theupper' audio frequency range.

26.' A stylus mounting for an'ele'ctric .translatingdevice comprising, combination, a magnetic A elongated reed-like member arranged` with` its principal jaais retending ,hori2ontally meansV for rigidly supporting oney end .of said member'for.

swinging movement of 'the outer front fendjofj said member about a verticalhinge ais, the. supportedend of, said member being,relatively'thiny 'horizontally and` wide vertically to provide. .a greater vdegree of Jleure .of said memberabout said .supporting means horizontally.-thanvertically, a cooperatingrmagnet havingpole faces.. at opposite .sidesof lsaid free end, andia stylus., "supported entirely v.bysaidmember near the `free end thereof, saidstylus having .its axis. arrangedv in substantially .a .vertical directionand. extendgated, relativelyy thin, .flexiblemagnetic: reed arv ranged with .its principal axisetending horie'onfl tall-ygI means,.-for 'rigidly-supporting one end ,tot

said reed-{withfthe' ,broad face :thereof in averti-M caly plane and vfstijening `means-.to provide a -s greatesdearzee, .0f fissurel 0f the Outer Aend 0f the reed horizontally, than vepticallyM and ga stylus Supported entirelubusa-id treed, melma-they tree-endif thereofandgrranyed .with its .axis .fsulistantiallyi in ,a .verticaldir.ecti0n,.a magnetic Structure hav-.1-

iny pole faces at opposite. sides of .said-.Omn :end of the reed, a coilzinfluenced b1/motions ,Ofi .Said 1:v

reed, theflua: varying throaaltfsaid resida .Said

faces.-,

ing .device yeompnisinas.in combinations:.anuelon-r. gated, relatively .thin-,fj'leiblze .magnetic reed-arr.- rangedwithy its principal. axisetending-'horizon-f tally, A'means-ford rigidly .supportingnoneoend. ot

said: reed the broad .face thereof .inz ,a fverti-L-e cal-plane to provide-a greater*` degreefofjleure of the reed-horizontally vthan-'verticallu/a ,stylus supported entirely by saidreedwneanthe ,freefendM thereof` and arranged with its: axis-substantially ina vertical--clirectionya magnetiestructure'ad.- jacent the-flexing portion `of-saidreed, and la coil: i 4

inductiveiy influenced` byA motion. ot said` reeds' 29. A stylus mountingv according to claim 28 wherein said coil surrounds the flexing portion of said reed.

30. An electric translating device comprising, in combination, a magnetic circuit including a pair of pole pieces denning a narrow air gap arranged in a vertical plane, a thin, flexible, relatively broad magnetic reed mounted in the median plane of said air gap with its amis in a substantially horizontal position, means for rigidly supporting one end of said reed with the other end thereof being free and positioned within said air gap, said supporting means serving to permit lateral fleure of said free end, a stylus secured to and supported entirely by the free end of said reed with its axis located substantially within a vertical plane and extending substantially at right angles to the amis of said reed, said reed being included in said magnetic circuit, and a pickup coil surrounding a portion of said magnetic circuit.

31. An electric translating device comprising, in combination, a magnetic structure including a pair of spaced pole pieces providing an air gap `in a vertical plane, an armature comprising an elongated magnetic reed formed of relatively thin strip material, mounting means for supporting said reed with its axis in a horizontal position and arranged substantially in the plane of said air gap, said mounting means comprising a fixed support spaced from said pole pieces for rigidly supporting one end of said reed with the 14 other end thereof being free and positioned adjacent said pole pieces to vary the flux of said pole pieces when the free end of said reed moves transversely of the plane of said air gap, the sup-n ported end of said reed having its broad face ar-f ranged in a vertical plane to provide relatively free lateral flexure of the reed, and a stylus sup-f ported entirely by said reed near the free end thereof with its ais positioned substantially vertically, and a stationary pickup coil surpounding a part of said magnetic structure in which the flux is varied by transverse movement of the free end of said armature.

DONALD J. BAKER.

REFERENCES CITED The following references are of record in the file of this patent or the original patent:

UNITED STATES 'PATENTS Number Name Date 1,573,739 O-Nell Feb. 16, 1926 1,756,966 Alden May 6, 1930 1,836,153 Capps Dec. 15, 1931 2,038,687 Sykes Apr. 28, 1936 D. 185,953 Williamson July 6, 1943 FOREIGN PATENTS Number Country Date 285,454 Great Britain Feb. 21, 1929 416,574 Great Britain Sept. 13, 1934 764,896 France May 29, 1934

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