US2351948A - Sound recording and reproducing apparatus - Google Patents

Description

- P. s. GA)l SOUND RECORDING AND REPRoDUcING APPARATUS June 20,1944;

Filed Feb. 26, 1940 i 4 sheets-snail;

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.June20', 1944.` v P. s. GAY 2,351,948l

SOUND RECORDING AND REPRODUCING lAPPARATUS Filed Feb'. 26,1 l1940 4 sheets-smet 2 ATTORNEYS Y .-June20, 1944. A P. s. GAY

SOUND RECORDING AND REPRODUCING APPARATUS V7 2, en

' mow@ June2o,1944. I 'ESSAY- SOUND RECORDING AND REPRODUQING AIVPARATUS Filed Feb. z6, 1940 v 4 sheets-sheet 4'.

'Low suRFAce I NORMAL' sulfur-Ace HIGH su'RFAcE ESULTANT '4- MASS INVNTOR aan?. i'ead ga# A o $05180 70 ..960 By 'm Mmmm; f.,

Patented 20,

assuma soUNn RECORDING AND nErnonUciNG manarus Paul Stead Gay, Charlotte, Mich., assigner to The Wilcox-Gay Corporation,l Charlotte, Michi, a

- corporation o! Michigan I Application February, 1940, Serial No. 320,823

ujoieime, (ct zii- 135V This invention relates to recording mechanisms and more particularly-to a phonograph recording mechanism of simplified and novel design 'particularly adapted f or use by non-technical unskilled users. A z

In the held of sound recording, over a period c! years, many producers have built equipment primarily to iill the vneeds of users concerned with commercial recording. These devices were designed without particular regard for either cost of manufacture, simplicity of operation or mass production requirements, since the eld of Dossible sale was considered limited in number. The

purchasers were in the usual case technicians iully capable of operating and maintaining complicated apparatus, and the initial cost of the equipment was not of prime importance due to' the nature of their utilization.

IFor the purpose of developing what seemed to be a much greater field for sound recording.

Y namely,the use of sound recording vin the maiorityfnhomesiorsuch.purposes as the copying at -radio programs, the recording and keeping of tnementos, personal or business correspondence,47V

musical education and' similar'elefmets incident to everyday lifeyl sought to develop an equipment that would produce sound recordsof equal or superior quality to those made by the. equipment heretofore on the market but that could be made easily in mass production at alow cost and would in amajor way be sel! adjusting and would be simple-feathelayman to operate;- .Y `The,inyentions' thus develpedaxdherein described iallinto two groups; rst, those having to do with the securing of high quality recordings with equipment capable of producing these In the average recording instrument of the prior art, the various mechanisms thereof have been seperately bunt inte and mounted en the instrument. After the mounting and assembling of alignment and general adjustment was re- .quired in order that the instrumentmight be made to function as an integral unit.-

One of the objects of the present inventionis to so arrange the various portions of the recording mechanisms thatthey may be associated as a complete unit without the necessity forcomplicated alignings and adjustments. 'I'his is ac-A complished not merely bythe mounting of all oi the mechanisms Aon a single base plate. which may thereafter be inserted in a proper enclosure,

but is likewise accomplished by the arrangement oi the variousparts of the instrument. each of which is so constructed as to readilyI cooperate with each of the other parts without any necessity for undue adjustment.

It maynbenoted in passing thatrwhile the ent v4f phasis of the presentvinvention is on recording mechanisms and while the recording mechanism 'is described as an integral unit, the pick-up of a phonograph sound producing instrument may be also integrally mountedln unitary association withthe recording mechanisms to be selectively placed in contact with a recording disk on the tum-table for reproducing sound.

By this means, every piece ofmechanism which has any mechanical movement vwhatever (even though said movement is electrically induced)' may be readily associated in a single unit with every other such piece ofmechanism and every member is so -arranged that it may be 'self-adresults yet less expensive to a'manuleptin',@thanxf--Jhlstiiig`vvith-1lespent/ML the other members of existing equipmentbecause of better fundamental design, and in the second group,inven tions having to dowith the simplifying of the equipment so that non-technical people can operate it without difllculty. 1 Each of these two'maior developments and requirements Aare however closely interrelated since many of the elements for producing jimproved results at greatly reduced cost also include simplifying elements which facilitate nontechnical unskilled operation.

The primary object of the present invention therefore is the provision in sound recording ap-v paratus oi means for producing high 'qualityreeordings with simplified inexpensive equipment. and, concomitantly, the arrangement of the sound recordingequipment to facilitate use thereof by the unskilled amateur consumer.

the unit without the necesfityioflignments0153.--n

various types.

An object of this invention therefore is the arrangement of vthe various mechanical' fportions of a recording instrument in a single unitary assembly which need not'require alignment or adjustment.

lassembly all the mechanical components'for recording'and transcription so that they inherently' meet adjustment procedures. and` so that the ments o f operation.

A valuableresult of this interrelationship and self-adjustment is ythat the equipment may thus 55. he: designed to meet standard -mass production phase or the/work was completed, a great deal Another Objectis te unite in, a singlevunit v equipment while nevertheless retaining' all of its I its lateral feed.

procedures, resulting in economy andl speed of manufacture.A While the resultant simplification in equipment, as well as in adiustment, alignment and operation,-brings the recording apparatus, into the realm of immediate use by the unskilled operator by reason of both its economy and simplicity. g

In the present instrument in order that it may .be used conveniently by inexperienced non-- technical consumers in their homes it has been necessary that any avoidable elements which might in any way interferewith o r make more difficult the recording process'should be avoided.

-. ope important disturbing element where e1eetric motors are used in order. to drive the turntable and other mechanism of the recording instrument is the vibration inherent inthe operation of the motor. Thus, for instance, where an induction motor is used, the forces applied 'thereto' during a single revolution vary in accordance with themomentary position of the energized components of the armature with relation to the eld poles, there being then an alternate increase and decrease of rotational force.

If the vibration induced by this momentary and continually recurrent change in the speed of rotation were reflected in the operation of the turn-table, then this` maycause a change in the recorded frequency which manifestation is commonly known as wows."

Heretofore, any attempt to overcome this,

cyclical variation in thepower pulse hasl depended upon a heavy rotating mass, that is, the

-turn-table, in effect. was made a heavy ily-wheel so that. its inertia might overcome the cyclical variations in the power transmitted by the motor,

' Such expedients rendered the entire unit -extremely heavy and expensive and more difficult in manufacture-and operation. A

' In the present Ainvention it has beenI found that a constant cyclical effective speed of rotation of the motor with respect to the turni-table may be obtained by suitable iiexible mountings which are soarranged as toabsorbany small 4 cyclical speed variations or eccentricities.

An important object of this invention, ther-e5 fore, is to'so arrange the electric motor and the mounting thereof with respect to the recording unit that altlough it is an integral part of the unit, the said unit may be insulated from the vibrations duced thereby. 'Ihis is preferably accomplish in thepresent invention by a resilient mounting of the motor and by a frictional speed reduction arrangement, the principal reliancebeing, however, placed on the resilient rimmed idler. A Heretofcre .e159 inV recording; units of` variousY kinds.'various complicated expediente and diflieult adjustments were necessary to operate .the

in relatiori to .the turn-table, but also in theu means -whereby .the arm might be connected am! disconnected from operation. Various'complb cated gears, cams, and interrelated and inter-- engaging clutches have heretofore been necessary' to operate the cutting arm, that is, to produce 4 m thelateral feed thereof withrespect to the, turn-,-

table. And additional clutches and interengli-- vdisc having an' absolutely true surface.

source and the engagement of an extension of l the pivoted base of the cuttingarm with the helix, the position of the cutting arm (raised or ylowered) being the sole determinant of the en'- gagement of its extension with the helix.

This object and the means of effecting it further emphasize the principal object of the present invention which is the integrating of the entire assembly into a single unit. And vit shouldA be noted that the purpose' is, not merely mounting all the members on a single plate but actually -so associating the various operating members that the operation land'function of each is directly related to and dependent upon the operation and function of all. of the others.

In prior recorder designs,emphasis was placed on the utilization, in the ilrst instance of a record Since absolute trueness is, for practical purposes, an

' impossibility due-either to wobble of the turntable itself or to irregularities in record surface, it is therefore necessary to create a design which will cut a satisfactory even groove into the surface of the record which moves it up and down. Another object -of the: present invention is to so arrange the cutting hea'd suspension in the cutting arm and the cutting 'stylus carried thereby that changes vin record height, irregularities in record material or manifestations ordinarily described by table wobble,- do not effect the smoothness or depth of the groove being cut, the while, by the cutting stylus, and hence be- `cause oi' this arrangement the table velocity remains unchanged.'

Other objectsof the present invention include Whisproyision of simplified indication of'recording level volume, novel means for collecting. and

removing shavqingsand a novel arrangement of` the play-back arm.

'Still other objects and uses of .the present invention will in part be apparent and in part pointed out .in the following description and drawings in which:

. mounting and the resilient lconnection betweenv `the motor and the tum-table, through a rubber cutting arm, such difiiculties being'present not .only in the means ofactiating the armitself Y ing mechanisms which required separate operil-V tion were also necessary in order jtoengage orfrom the influence of.

disengage the cutting arm 4Figure l'isa view inl perspective of the recording 'unit assembly with.th e turn tableeremoved.

Figure 2 is a cross-'sectional view taken on line 2 -2 .of Figure 4 looking in the direction of 'the arrows andshowing the cutting arm of the recording unit of Figure 1 in lowered position so that the stylus 'engagesthe -disk upon which a record is to' be made.

rieure a is a view'in perspective of thestylus. v f li'igure 3a is a cross-sectional view 'on line laf-la of Figure 3..

Figure- '3b is a cross-sectional .view on* line 8gb-3b of Figure. Y

- Figure 3c is another perspective view from the opposite side of Figure 3. 1

-Figure 4 is an elevation partlyin cross-section taken on line l-l off'Figure 1 showing the turn' table in piace uponits post and the'cutting arm engagement with the disk upon the turn-table mure s as top puin vieri partly breken rey elevation taken along line with the mounting plate I2.

line 6-6 e of the play- Figure 10 is a cross-sectional view partly in IIJ-I of Figure 9, looking in the direction of the arrows.

Figure ll is a diagrammatic illustration of cutting head behavior at three possible phases of operation.

Figure .l2 is a graph of the action of the cuttinghead suspension at three possible phases.

Figure 13 is a graph of the eiect of various forces on the depth of the groove produced by the cutting stylus. r

Referring now to Figurel, there 'is here shown an enlarged perforation 2l in the arm 22.

in perspective the base plate I0 of the recording assembly having the form which it takes when or other unit. The base plate I0 carries secured thereto by screws I I or any other suitable means a mounting plate I2 which registers with any necessary or suitable orifices in the base plate I0 which it however covers. The mounting plate I2 carries on its upper surface the various driving mechanisms hereinafter described, but `it should be noted that a turn-table hereinafter described mounted on the turn-table post covers mounting plate I2 entirely and thus conceals the various mechanisms protruding above the top thereof.

The drive mechanism for thev lateral feed of the cutting arm comprising the arm and helix beneath the base plate I0 and hereinafter de-` scribed obviously is not visible when the base plate I0 is mounted in the top of 'its cabinet.

In the following explanation, reference particularly to Figures 2, 4 and 5 as well as Figure l will serve to further illustrate each of the parts herein mentioned.

The drive motor Il of the'recording unit (seen particularly in Figures 2 and 4) is resiliently mounted on the mounting plate I2 on latex rubber gromets I5, I5 (see also Figures 2', 4; and 5). By this means the motor Il is completely dissociated from Athe remainder of the mechanism since the only connection of the motor therewith is throughthe mounting I5. The shaft I6 of the motor projects through an opening in the mounting plate I2, the opening being of suincient width that no contact is made bythe shaft (See Figures 1 and 5.)

The shaft I5 carries an arbor I1 (Figures 1, 2 and 5) which is of the exact diameter so that whenengaged. with the rubber rim I8 of the idler I9 which in turn engages the inner surfaceof the ange (see Figure 4) of the turntable 1|, will produce a predetermined reduction of speed resulting in a rotation of the turn table 2I at a predetermined speed.`

Thus, in addition to the resilient mounting of the motor which disassociates the motor from the mechanism. the connection from the motor to the turn table is not a direct rigid` mechanical connection but is a frictional and resilient 1 connection by, reason of the interposition of the mounted in the top or other portion of a cabinet rubber tired idler I9 between the drivingarbor I1 and the turn-table.

As seen particularly in Figures 1, 5 and 6, the

idler I9 is not mounted directly on the mounting plate I2, thus further tending to dissociate any vibrations which may be induced even in the mounting plate by the motor from-the main drive of the turn-table itself. A, The idler I9 is mounted on the sliding arm 22 which is retained in its association with the mounting plate. I2` by means of the screw 23 passing through mounting plate I2 andthrough A washer 25 is placed over the screw 23 and is so arranged that it will at all times cover the large perforation 24 and lock nuts 26 are applied to the end of the screw.

The lock nuts comprise preferably two nuts rwhich may be tightened against each other in such a manner that the washer 25 is not pressed tightly against the arm 22 sothat the arm may slide upon the mounting plate I2 and is limited only by the abutment of the periphery of the perforation 2| against the screw 23. This gives the arm a predetermined amount of play with relation to the mounting plate I2v and correspondingly gives the idler I9 supported thereby a degree of play with respect to the arbor Il of the drive shaft I5.

A lug 21 struck up from the mounting plate I2 registers with a slot 28 of the rsliding arm in order to guide its movement so that the moveposition ofthe perforation ,it will by reason of the fact me'nt thereof will `be in such direction as to cause the idler I9 to be in contact with the arbor I1 under virtually all conditions.

Spring 29 captured at 30 in the mounting plate and'guided by the lug .'iI4 struck up from the mounting plate engages a lug 32 of the sliding arm in order to tend to drive the idler away from the arbor, exerting just suicient force for this purpose. The turn-table 2I preferably is of such diameter that when mounted upon the turntable post I3, the inner surface of the flange 20' thereof will press the idler I9 against the arbor I1 so that motive power may be transmitted to the turn table from the `arbor I1 by frictional engagement thereof with idler 'I9 and by frictional engagement of the rubber rim I8 of idler I9 'with the inner surface of the ange 20 of the turn-table 2 I.

The turn-table 2I may be weighted by means of a nat plate which is welded on top of a conventional phonograph turn-table.

The radius 4therefore of the turn-tableshould i be such asto force the idler I9 against the arbor I1.` Should the radius be slightly smaller, then the vposition of the idler I9 with respect to the arbor I1 is self-adjusting. That is, instead of the idler being forced directly against the'arbor I1, that the perforation 24 is much larger than the screw.23, be caused tov come in contact with the arbor I1 not at the. .point towards which the idler lhas been forced:

but the position of the pivot 33 of the idler I9 with respect'to the arbor I1 will have been moved arcuatelyseveral degrees away from thatwhich it would have assumed at the niet position of contact above-mentioned. Thus in Figure 5 the 24o! the ann 22 with respect to the screw 23 is shown as a position wherein the turn table v2l is of the smallest radius, the. pivot 33 having been moved several degrees clockwise from its original position with respect tp the arbor I1. v' A turn-table of slightly -largerradlus will permit the perforation 24 of the sliding arm 22 to assume a position so that the screw 23 be somewhat centrally located with respect thereto while when th'e turn table 2| is completely removed, the screw 23 will be in a position along the periphery of the perforation 24 which is approximately 120 removed counterclockwise from the position shown in Figure 5. Thus it will be seen that with the turn-table 2| mounted in place uponits post I3, operation of the electric motor I4 will result in rotation of its shaft I6, thus resulting in rotation of the arbor II carried thereby. The frictional engagement of the arbor I1 against the rubber rim I8 of the idler I9 will result in rotation of the idler and the frictional engagement of the rubber rim I8 with the inner surface of the flange 20 of the turn table 2| will result in corresponding rotation of the turn-table. p The diameters'of the arbor, idler and turntable may be so arranged as to provide for the requisite speed reduction from original motorl speed to turn-table speed. There is no possibility of the transmission of motor vibrations or of characteristics resulting from uneven motor operation to the turn table itself since the motor is resiliently mounted with respect to the mounting plate I2 and has only a frictional engagement through a resilient rubber rim I8 with the turn-table.

Examination of the figures will thus show that there is no place where the motor is not resiliently isolated from the turn-table 'and the rest of the assembly. Such resilient isolation of the motor is of real importance where it is desired to dampen out the power pulse generated where an induction motor is used.' During any 360 cycle of rotation of the motor, the energized portions of the armature assume different positions with respect to the field poles thereby causing an alternate increase and decrease of rotational effect.

If the motor. were directly connected to the turn table or if it were' sovarranged in association with the turn table thatA there were no resilient connection therebetween, a high frequency The resilient; mounting and resilient connections above described result in the motor vibrating back and forth againstits resilient mounting in accordance with and in a direction toy compensate for-the proportional variation in speed and thereby irons out this variation.

This solution 'presents what is believed to be a completely n'ovel application of DAlemberts principle of dynamics that a moving mass exerts.

inertia reaction forces proportional to the inertia of `the mass and e has always been thought necessary to mount the motor solidly and immovably so that the mass its acceleration. Heretofore it' thereofV may have sutliclent purchase to transmit a driving force through the shaft. In the present invention the important element is that. the field poles, or in other words, the mass of.

the motor itself, is resiliently mounted, the arma; ture and shaft of the motor being connected and mounted in the ordinary way between the poles. Any sudden increase in the power, 4that is, any power pulse, impinged upon the rotating shaft will result in a counteracting reaction in accord.- ance with DAlemberts principle. This counteraction is not caused to take place against a solid immoveable mass but, by reason of the resilient mounting of the -main mass of the motor, the inertia reaction-results in a definite movement of the mass of the motor of suflicient moment to counteract the power pulse, thus dampening out the .power pulse and resulting in a net rotation of the shaft with respect to the turn-table which is not increased by the power pulse.

This resilient mounting of the motor and isolation thereof from the recording equipment, that-is from the equipment which is actually to make the record, is a distinct improvement which has been found to be of real` value in actual commercial operation. It is important, however, that while isolation of the power pulse be effected and while all sources of vibration or all sources which may result in the creation of disturbing noises in a. recording, be obviated, the various portions of the apparatus be integrated in their operation so that they are mutually interdependent and constitute together a single complete unit.

In the present device, the compressing of the tire I8 on the idler I9 does not at any time substantially change the speed ratio between the pulley I'I of the motor and the flange 2| of the turn table, since irrespective of the extent to which the tire I8 may be compressed, the linear speed of the tire I8 induced-by its contact with the pulley I'I of the motor is translated by its contact withthe flange 2I into a linear speed for the flange 2I of the turn-table which is always substantially equal to the linear speed of the pulley I1. Where this condition is not fulfilled, vibration causing a change in compression of resilient members will produce wows.

The resilient mounting of the motor and the isolation thereof from the recording equipment, that is from equipment which is to make a record of sound and the consequent mechanical filtering of torque pulsations and similar vibrations is believed to be novel.

Screw 2 I0 may be so arranged in the journal of post I3 that it may .be rotated inwardly to engage the annular groove 2I I thereof (Figure 2) to prevent the post or spindle I3 from falling out during shipment. 'Ihe screw may be rotated out of engagement with groove 2II after shipment; or the groove may be suiiiciently wide so that the screw does not bear against any portion of spindle I3 when the mechanism is arranged in upright position.

An important element of the present assembly is the integration of the cutting arm and the lateral feed mechanism thereof with the remainder of the assembly and a most important element to be observed is that the lateral feed of the cutting arm is directly related to the position of the cuttln'g arm, that is, a mere change in position of r isolation' between the cutting arm itself and the motor which forms the ultimate source of power Likewise, the arrangement of the cutting head lin the cutting arm is such that further and complete isolation of the cutting stylus from the motorv isinsured while nevertheless the cutting arm is ultimately driven by the power of the motor.

The cutting arm J4 (Figures 1, 2, 4 and 5) is pivotally mounted -by means of the pins or screws 35 on the platform 36. 'I'he cutting arm 34 may f shaft l1 in such a manner -that shaft $1 and the end pins of atoggle mechanism, whilethe ro. A

.armllmay form 1in a vertical plane only so as to assume for instance the position 'shown in Figures 2, 4,

and 5, but any rotation of thecutting arm 34 in a horizontal plane will result in rotation of the Aplatform 36 and likewise any lrotation of the platform 3B horizontally will result in rotation of the cutting arm.

, e platform it is keyed to and mounted upon platform 38 'must Anecessarily rotate together. Shaft I1 is rotatably carried in the journal I8 `whlch is mounted upon the'base plate Il, the

shaft l1 extending beneath base plate I0 and carrying at the bottom end thereof and keyed thereto so as to rotate therewith the lateral feed arm l0. The shaft $1 may also slide vertically in the journal 38.

A compressionsspring A4U is mounted between the lateral 'feed arm I! which constitutes virtuallya right angle extension of the shaft Il and the bottom of the hase plate I0, thus exerting a downward force uponv the shaft l1.

Raising the shaft 31` will therefore result in a raising of the lateral feedl arm 3l and lowering of the shaft 31 will result in a corresponding lowering of the lateral feed arm 39.

.The means lfor raising and lowering .the shaft 31 in `order to cause araising and lowering of the lateral feed arm 30 is a direct lfunction of, the

position of the. cutting. arm $4, that is, when the cutting arm 34 is in the position shown in Figure 1, the lateral feed arm I! is raised and when it is inthe position shown by the solid llnei of Fiaure 2 the lateral feed arm is lowered.

This raising and lowering of the shaft,is accomplished by the pivoted mounting in e, vertical plane of the cutting arm 34 on the pins il and by. the pivoting links or lift levers 4|, the said links being rotatably connected at 42- to thecutting arm and rotatably mounted in -thenotches 4I, 43. of the platform 44.

'Ihe platform 44 is carried by the Journal $8 and is ilxedly arranged with reference to its height above the 4base plate Iii and does not rise or fall with the shaft. I1. It is held'in xed vertical position by means of the engagement oi' an inner annular portion. thereof in the annular groove 45 of the Journal so that while it may rotate with respect to the journal and not impede the horizontal rotationl of the platform 36, and its associated' shaft Il it may not change its vertical relation .with respect to the base plate it.

For purposes of the following description, the

pin mounting I! of the cutting arm and the notch mounting 4I of the link 4i may b'e regarded as tatable mounting 42 of the link 4I in the cutting beregardedasthekneepinofthe toggleme'chanism; that is. thetoggle maythen consistof-animaginarylinkIB-n andlink *5 the eompression ,spring 4l. Then as pin 3l in its vcountercloclrwise movement with respect (to. pin 42 passes out of alignment therewith, the

tendency of the compressionsprlng 40 acting on shaft I1 which in effect therefore acts-on pin 3l is to bring the end pins le and 4l of the imagmary toggle mechanism close -together and to `force the pin 42 out thus resulting in the tendency ofthe compression spring 40 acting on shaft 81, to'draw the cutting arm -into downward position and to lock the cutting arm into downward position.

By this relative arrangement of the rotatable mounting 42 of the link 4i with respect to the by the production of the toggle effect above described, the compression spring -40 operates'to engage the cutting arm in raised position when that'is desired so that the cutting arm will not fall accidentally and thus. injure lthe stylus or` destroy a record underneath and likewise to engage the cutting arm in lowered position and hold it4 in lowered position by the spring action of spring 40. y

There is, in other words, the true snap action of a toggle wherein the same force may be utilizedto drive the end pins of the toggle togetherI no matter which side of the aligned position one toggle extends with respect to the other. There which locks the cutting arm in raised vertical position against any possibility of accidentally failing and likewise iocks the cutting arm in iowa -v .ered position.

Bothmeans depend on the operation of spring 40 which'is so arranged that manual engagement of the end Iof the cutting .arm by the ciasping of the finger buttons 46 (Figure 1l will be sufficient to overcome the action of spring 4l.

The toggle action herein tion of imaginarylink lie-42 in connection with the link 4I and the'action vof both about the pin 42 is clearly Ashown in the solid and dotted lines It will benoted, however, that when the cutting arm I4 isin a raised position, the tendency of the spring `4I to P1111 lit downis counteracted by the fact that the tops of .the links 4| press against 50 the bottom edges of the nanges 4l of the platform Ii and that the spring is thus prevented from pulling the platform down; and when the cutting arm I4 islowered. then' the only element which prevents the pulling ofthe platform down is the 55 pressure of the cutting arm 34 againstthe adjustment screw 4I onthe platform. (See Figures 'l and 2.) A y This adjustment screw may be so arranged as i to insure that' the cutting arm is at thel proper su um aboutrthe mor knuckle when the position in the cutting head to function correctly elements are in the positionshown in Figure l,

.then imaginary unan-azimut in alignment direction, the ilrst tendency'is .to bring the imaginarylinkiB-l into aliment with thelinkll. 7

In other words, the -movement of the pin with respect to the knee. pin 42- is counterclockwise. The initial movement necessary to bring the .pivot mounting 8 4: into alignment first results ina n l i slight raisins of the shaft S'l4 against the forcel'of' 15 to secure theloeking previously described in the and to further insure that the flateralfeed arm ranged as to go past'dead center position, locking j the arm in raised position against any possibility `of falling.

The cutter arm lever 4i provides a thrust along thelength of the arm which acts to o .take up slack and whatever lost motion exists. a spring asisprovidedto cutting arm itself may not be of suiilcient man# rotatable mounting of the cutting arm 34 and" is then what may be less-technically called lockdescribed and the ac e complete downward travel of the pivot post shaft when the cutter armialowered. Thisspring isnecessarysincethe position or the proper pressure in the sembiy is completed, a' lock nut ll making -lowered position. v

- The height adjusting screw 48 is provided for positioningv the cutterarm vertically and obtaining the. proper height of the knife edge pivots,

hereinafter described, relative to the record surpermanence face. Locking nut 48a provides for of the selected adjustment.

When the cutter arm is 'lowered so that it is pressed upon the height adjustment screw 4l, the

' cutting'head is practically in its normal operating position and equilibrium of cutting conditions is obtained automatically if the record surface is rotating or when the record starts rotating. Y

The height adjusting screw 49 controls what could be called normal conditions. 'Ihe adjustment of this screw is necessary to strike an intermediate position so that the cutting angle may change above and below the normal value and the spring action still compensate for the changes that would otherwise occur in groove depth.

The drive mechanism of the lateral feed arm operates from and is a direct function of the rotation of the turn-table. ,The operating mechanism comprises a rotating helix, spiral or screw 49 (Figures 1,4 and 5) which is operated by the l' worm and spiral gear arrangement Sli-5i shown of 'the helical screw 49 will also result in a lateral feed of the cutting arm 34, 'Ihat is, as the helical screw rotates in 'the manner hereinbefore described, the pawll? will be carried progressively'and steadily )inward upon' the threads' of the helical screw 49 toward the turn-table mounting post I3 resulting in the lateral movement of the cutting arm 34 from the periphery of the recording disc toward the center thereof.

It has been usual in the design of recording instruments to use sectors, gears, heart-shaped vcams and other similar elements to provide the lateral motion for the cutting arm.

Not only are these means expensive, but they are involved and mechanically complicated. requiring intricate and extremely exact adjustment. The pawl of the present device contacts the lateral feed orhelical'screw 4l, in such a-'manner in Figure 2, the spiral Il being an extension of the tum-table mounting'post I3. Rotation' of the turn-table resulting in rotation of the spiral results in rotating of the gear 5i which results in rotation of the helix or helical screw 49 to whichvv it is attached.

The lateral feed arm 39 keyed to ,the shaft 3l carries at the oppositeend thereof la pawl 52 which registers with .the threads of the helical screw 49. As will be noted from Figure 2, when 4the cuttingarm is lowered, it, in the manner hereinbefore described, causes the lateral feed arm 39-to be depressed. This depressing of the lateral feed arm I9 causes the pawl 52 t0 engage the threads of the helical screw 49. And in the that when positioned in the center of the helical grooves being further apart in the center of the record than they stre at either'` the outside of the record or the inside ofthe record. However.

the extent to which they` are nearest or furthest lapart depends upon `the cosine ofthe angle of the lateral feed arm to an imaginary perpendicular erected on the lateral feed worm or helical screw at the point of contact, this angle being small for all values by reason of thelngth of the lateral feed arm and the distance of the shaft ,31 from th'e helical Vscrew 49 and being zero `when the arm is in the center of thevorm at manner hereinbefore described, raising of the cutting arm 34 causes a corresponding rise of the shaft 31 and a corresponding rise of the lateral feed arm 39,- thus disengaging the pawl l2 from the threads of the helical screw 49 in the manner shown by the dotted lines of Figure( 2.

'To make assembly rapid and obviate the necessity for holding to close-tolerances in the machinins of the assembly. the lateral feedv arm does .not itself directly carry the -pawl which engages the helical screw but a resilient means isprovided- .between the arm and the pawl. lof such resilient means results in the effect that *any deviation from trueness in the lateral feed 'I'he provision will not cause an uneven power demand from the motor resultingin"wows.

.Cantileverspring Il is attached by means of rivets I4, B4 to the lateral feed arm 39. The

" free end of the lateral' feed arm I9 as seen par- 'ticularly in Figure 2 carries adjustment screw an angle of `90 thereto; the variation is small and the economy and mechanical perfection and simplicity of the device more than compensate for the slight difference in the spacing apart of the grooves of the record.

A stop 49a is provided for the lateral feed arm toprevent the carrying of the cuttingstylus too close to the center of the recording disc. 1

The worm driving the feed screw is integral with the turntable shaft; the feed screw by reason of the fact that it is driven from the shaft of the turn-table is thus resillentiy isolated from the driving motor in the same way that the turntable itself is, resilientlyisolated, that is, the

.power transmission path from the motor tothe I feed screw includes the rubbertire Il.

5l which maybe raised or lowered to adjust the pressure ofthe cantilever spring U3 after the :1e-

adjustment a permanent one. n

The pawl need not be a. separate` piece of'matei rial, lbut for purposes of economy as well as ease and simplicity of manufacture, the pawl liz mayy ,merelygbe a lug orpfiange struck up out of the ma al of the cantilever spring thus integrating `the awl with the remainder of the lateral feed It willthus be seen that rotation of the turntable mounting post i8 which results in rotation 75 stamping.

berequiredintheremainderoftheassemb and 'topromoteanoptiinumsprinii' ly 'I'he worm and pinion driving the feed screw are s -totally enclosed. The benefit is one of keeping foreign material of any sort. for instance shav` ings ordustn completely clear of the gear teeth. This type of construction permits practically permanent lubrication because the enclosure may benter'sny nues witnlubneents.- f

The worm provides lifting action to the lubricants while gravity is"vi'p`1;iosed4 and a lcirculation oflubricant results. f

'mescrew enna iocxing'nut n are provided' to properly adjust spring mcmber'll'l the necessity for accuracy which would otherwise pressure. The followera'rm knife or resilient member-are preferably a one vpiece This minifedre and the' compliant connection changes,

Verticaly compliance is provided between the follower arm and its knife edge which (a) minimizes the accuracy` required in vertical alignment; (b) provides a certain amount of mechanical filtering to minimize transmission of vibrationv between feed screw and follower arm: and also ascneisff a. y

such as to permit the stylus end ofthe cutting takes care of whatever eccentricitymay exist in` the feed screw regarding vertical adjustments: (e) will act as .a clutch in case the follower arm reachesthe limit of its allowable travel and brings upagainst the stop 48a; in which c'ase the knife edge will ride up the side of the thread of screw 4l andfall back into thev groove. i

The cutting head 60 (see Figuresl and 2) is resiliently mounted .in the cutting arm 34. The

cutting head comprises a member 6| which is responsive to amplified voltage impulses transmitted theretoby the wire 62, the'said member` carrying a stylusg63 to which are transmitted vibrations corresponding to the impulses received by the microphone.

The cutting head 6l! carries a plate riveted to the back end thereof,the said plate 64 having head to ride lower within the cutting arm while should the end 13 be depressed, the stylus end of the cutting head will ride higher..

This knife edge ralorum Yin provides for e playless bearing forV the, cutting' head and therefore providesfor a high degree of lateral 'stability'by virtue of the spread between .the contacts.

v'I he spring suspension by means of the spring 6l lserves yfurther to maintain a constant power demand from the motor when its tension is corvrect. The springin correct adjustmenthas the riet effect of .decreasing the total weight of the cutting head and when the head `is moved up in the case of a record that wobb1es, the amount of spring tension `becu'r'ies proportionately less..

However, the spring should beand i5-long enough so that the proportionate amount lof varia knife vedge which abuts against the angle 65 of the member. 66. The plate 64 also carries a perforatedextension 61 which may be engaged by the tension spring 6B. The member G6 is riveted tol the fiat plate 68a whichis extended to-the flat plat'e 69v which in turn is secured by the 'screws 10 to the cutting arm 34. I'he mounting plate 69 carries at the rear end thereof the U-shaped channel 1I in which the screw 12` is mounted. The screw is arranged so that it may rotate with respect to the flanges of the U-shaped the perforated projection thereof 61 and by engagement of the opposite end of the spring 13 .with the threads 12. The end of the spring 18 comprises a small perforated plate through the perforationof which the screw.12 passes, the

periphery of the perforation engaging the thread of the screw. Rotation of the screw 12 will cause the end 12 of the: spring 68 to rise or fall in accordance' with the screw and thus adjust the suspension of the cut'- ting head 60. The stylus securingscrew 14-which is located in the front of'the cutting head pro- ,iects through an oblong opening 15 in the front of the cutting arm, the said oblong opening per-'- mitting the raising or lowering of the cuttingv head either by reason of the change in the suspension or the raising of the stylus inthe manner hereinafter noted.

The total possible vertical movement Aat the cutter 'head is restricted by the screw 14 in the slot l5 so that the arm can be raised and lowered y as a single unit withone hand.

direction of rotation'of the ation in tension should be of no consequence.

Theimportance of this willv be understood from Athe following description of the mounting and operation ofthestylus end o'f the cutting-head;

Previously in the design of .recording equipment, the hope of obtaining freedom from low frequency wows" lay in the provision of a. table with great weight so A that the kinetic energy stored in this revolving mass\would iron out any change of rotational speed. Unevenness of table velocity is caused by a change in the power demand from the motor; that is, when the power increases, the motonslows down and when it decreases. it speeds up again.

Oneof the most important reasons for the un-y evenness in thevpower demandarises from ya wobblingA or vertical movementof the recording disk or irregularities in the surface thereof also resulting in vertical movement.-

The present invention seeks to lsolve this problem not by the addition of rotative mass to the turn-table but by proper provision in the cutting head suspension, thatis, by the formation of -r the suspension herein described which results in a practically constant. power demand from the motor.

The possible dlillculties arising from such vertical movement are, first of all, a variable' depth of groove and, secondly, a variable power demand on 'the motor driving the tum-table.

' The firstdiiliculty results in a recordwhich is unsatisfactory 'in its 'mechanical nature. The

second difficulty results in arecording which was not made at a constant speed. If thisrecord is played back with the `constant turn-table speed,

the pitch dthesounds recorded will as a result wows.l A V. v

The rincipfallwork doneby the motor drivingV the turn-tablej'is that of removing the shaving's while the raising ortho lowering Aof the end ,Q

- u'bylmeansof inerotation of ujie screw 1: aci-- suspension of the cutting head ll, the spring nevertheless is preferably of sumlusts the l angle of without changing the degree of resilience of the noted that should the end mounting. It will be l theangle of suspenslonis 1I of the spring rise.

from the record.v That is inaddition to the relatively constant power demands occasloned by fric-- tional losses inherent ,inany such assembly. l

4I1' for any cause. the size of the shaving is altered,fthe.power drawn-on the motor is correspondlngb' altered.

There are two principal of cut or Vsize of shaving. The ilrst is the pressure on the stylus and the second. the angle at I' which thegstylus cuts. In my design,- variations"- in these two factors were made to opposeeach other sol that'a uniform shaving resuited, even though the height ofthe recordsurface varied. The change in pressure through 'spring actionandthe'change in cutting angle resulted fromY the changing height-.ofthe heriomenon is'v commonly known as factors effecting depuiA required wasI obtained f record surface with respect to the point at which the cutter head was pivoted. s

' face 11 of. the stylus is initially ground toa critical angle. That is, when thestylus is inserted in the chuck 18 of the cutting head (see Figure 1) and engaged therein by the screw'll, the flat assunse ting depth occasioned by a change in' cutting angle will not be a. linear function. 'I'his means i As seen. in Figures 3,13a, 3b, and 3c, the cutting vsurface 19 of the stylus determining the position ofthe stylus in the perforation, the'angle of the cutting face 11 is such that with theturn-table' continually rotating in a single plane, a groove of optimum depth is cut.

.3 to 3c as well as in Figure 2 where instead of having the usual large angle between the facev of the stylus and the surface of the record, the initial angle is smaller.v In this manner, automatic adjustment of the cutting angle in accordance with the momentary height of the turntable at the point of cutting becomes more readily possible.. The cutting angle is such that even though there should be a. relatively great amount of, vibration in theturn-table, for any reason, resulting in an unusual increase in height ai'. themoment of cutting, there will nevertheless be a sufficient angle to permit cutting'. -For purposes of further definition, the cutting angle will bevunderstood to be the angle. between the cutting face 11 of the stylus and the surface of therecord, measured in the frontal plane. The cutting .angle is so arranged that when a small variation in this angle is brought about, by 'a raising of the stylus owing to a wobble of the turn-table and a consequent moving up of the cutting head, there is a tendency for a less deep groove to be cut and when it goes down, there is a tendency for a deeperv groove to be cut.

ANALYSIS F MECHANICAL BEHAVIOR or CUTTER Y Hman SUsrnNs'roN l I. Static condition n Referring now to the diagrammatic illustration of Figure 11 at the left (at L) is shown the conditions obtaining when a low record surface` is encountered. The cutting angle is large, Counter-balancing the effect of this cutting angle is an opposed spring tension-which is relatively large. these forces 'and their sum is shown as a resultant. Thesecond position (at N) correspondthat a complementary non-linear variation in the vertical pressure component derivedthe spring tension is desirable. I

The diagram of Figure 12 illustrates how this may be accomplished. Pressure on the stylus y Amay be considered essentiallyI equivalent to the torque exerted about the pivot point in the cutter suspension. This torque is a resultant of the weight ofthe cutter head itself, acting about that point and the spring tension. f

The spring tension produces torque which isproportional to the product of the tension of the spring itself and the effective length of arm on` which it operates. It should also be noted that the effect of change of the axis of the spring itself produces important results in changing the moment about the pivot. Such changes may be utilized to emphasize and equalize the results herein pointed out. There are three positions shown in the diagram.

At point a is illustrated the first point at which we assume the spring is attached to the cutter head assembly. The-spring tension is brought about by an extension longitudinal to the line indicated as i. The effective crank arm is indicated as the perpendicular distance a. .Other positions are shown at b ando.

It can be seen that operating at a small angle 6 results in changing the effective length of th crank arm at a much greater rate than the extension of the' springas the angle 0 tends to increase.

The point at which the other end of the spring is secured is another controlling factor. It can be seen that its positioning with reference .to the pivot points and first end of the spring is a factor entering into the control of the effective length of the crank arm.. Itis apparent that this type of design allows obtaining the exact pressure desired for two positions of the cutter head and a.4 close approach at other' points' over a wide range.

. In other words, if the torque which would be required for each possible positioning of the cutter head iseXamined, this design permits the obtaining of exactly that pressure at any two A Vselected positions. The curve of torque plotted The arrows indicate themagnitude of ing to a normal surface shows that the cutting angle has been decreased and the axis upon which the` spring operates-has been changed and giving a larger resultant pressure on the 'stylus which off-sets the effect of the changed cutting angle.

, In thepresent design, the axis of the spring v is l changing to a predominant degree ove:k the, change in tension. Dependence on variation of spring tension may produceunpredictable pressure results. while with a minimum variation in tension, changes in the axis ofthe spring will the tension of the spring has also been decreased.

produce predictable and regulatable variations L cutting angle 'decreasea It is to be expected, l and experience indicates, that the change in cut is proportional to the vertical -against vertical positioning of the cutter will thus closelyy approximate the desired curve byl virtue of being -the exact value required at two 'points and of the general form desired at all other points.

Staticv conditions exist as long as the rate of change of height of .the 4 record surface is of low value, since inertia effects depend upon this -rate of change. 'I'his derivative is dependent not' only upon the magnitude of the change but also upon the time within which the change occurs.

When this 'derivativebecomes sumciently large, another factor becomes Aof importance. i

vII. The dynamic condition-'Stylus measurel due;

to inertia 'e17ect Whenever the` height of the record. surface changes, the mass presented by the cutting' head isaccelerated. The incremental stylus pressure acceleration.- Since this factor is variable in practice, good design requires that the effective mass be kept low. thus keeping the increment low regardless jof the percentage variation. 4

Any conceivable variation in record' surface height may be encountered and no design csa..

from

design then is that of minimizing the magnitude of the effect. The mechanical disposition of the.

mass necessary in'the cutting head is an aid to this end. 'By locating the pivot pointnear the center of mass, the moment about the pivot point is minimized. l

Sincethe incremental pressure is a derivative of the vertical displacement with respect to time, the effect on groove depth is in quadrature with the variation in vertical height. This q ladrature relationship obviates the possibility ci canceiling out its effect by either control ovtr cutting angle or spring tension since they are respectively out-of-phase and in-phase with thel record surface height.

In Figure 13 is shown a cycle of variation of record surface height together with the variation ,in the three effects we have been considering. Curve 2 shows that the effect on groove depth derived from the spring varies in phase with the record surface. in the diagram indicates a greater groove depth; indicates lesser groove depth.)

' Curve 3 indicates the out-of-phase relationship of the cuttingangle effect. Curves 2 and 3 may be made to oppose each other as previously described. In case they do not exactly cancel, the resultant sum of these two curves will vary the phase relationship similar to one or the other depending upon which one predominates.

Curve 4 represents the effect due to the accel. eration of the mass. of the cutting head in the dynamic condition. It can be seen that this wave is shifted 90 lone way or the other from any pos sible combination from, curves 2 and 3.

' free of the record surface for a while, and then Curve l therefore cannot be cancelled, al-

, though the cumulative effect may be phase dis--l placed due to its action.

The conclusion to be drawn from the above is that the mass which is accelerated should be kept at a minimum, and its suspension should result in the' least possible moment In the present design, the' closepositioning of the'pivot with respect to the center of mass accomplishes this Purpose.-

A further design consideration is that involv' ing verticalmechanical resonance occasioned by the mass of the cutting `head in conjunction with-the spring. Associating any mass with a spring brings about the condition where movement of the mass becomes easiest at some specinc frequency. It is desirable in a cutting asrepeats the cycled Fromv the above, it lfollows that the mechanical lresonance frequency of the cutter with its suspension should be made as highv asfeasible;` 1n addition, in the present design the torque derived from the spring is allowed to actually increase above what other considerations would require to minimize this digging-in tendency. 'I'he object is to avoid foipractical purposes the possibility of a dead center condition beyond which the cutter would tend to bury itself.

f The possibility of the occurrence of this phenomenon is of course to avery great extent obviatedby making certain that the resonant frequency of the spring is sufficiently high to avoid I causing the stylus lto clearV the surface of the Y record in the manner above described.

If the lifting action of `the spring increases more rapidly than the cutting angle can cause the stylus to bury itself, the lcutting arm may be lowered very abruptly to the cutting position and proper cutting equilibrium will automatically establish itself.

In the present assembly, operation( by inexperienced users is greatly facilitated by having cutting equilibrium automatically established even though the arm is lowered rather inexpertly.

summarizing the important features of the above cutter suspension design) (a) Minimizing inertia effects by pivoting the cutter head near its center of mass. 4

(b). Mounting with knife edges occasions a minimum additional mass'and minimum frictional effects.

(c) Horizontal spread between points of contact on knife edges insures continuous axial alignment of the cuttinghead and high transverse stability.

Counteracting vchanging cutting anglesl by means of spring action.

This can be done with the spring adding to stylus pressure as well as when the spring's'ub-l tracts,as is hereinafter described.

sembiy to be able to follow surface irregularities as rapidly as possible. If the mechanical resonance frequency of the cutting assembly corresponds to a higher rate than-the' rate at' which surface irregularities' are encountered, satisfactory cutting maybe obtained. v s

1f, however,.asurface irregularity exists at a more rapid rate than that corresponding to the resonant frequency of the cutter assembly (the ability of the spring to yield thereto). the, stylus will-notremaln in continuous contact` with the record surface.

When irregularities occur at a; frequency close to the mechanical resonance of the assembly, the

incremental pressures become very much greater in magnitude. irregularities occurring at a more rapid rate may result in the stylus being lifted completely clear of the record surface momen- "mling-ln is very apt to occur undersuch conditions-an action whereby .the stylus cuts into the blank very deeply, cuts or tears itself Spring mounting permitting independent design control over (a) static stylus pressure; (b) rat'e of change of stylus pressure spect to vertical displacement of stylus;

(c) 'pressure holding knife edges in contact.

A relatively high mechanical resonance fre-4 quency of the cutter in its suspension -in a ver tical plane.

As has been point-ed! out, the present device may be utilized either for cutting records or for playing records which have already been cut. AThat is, a suitable pick up arm Ilm may be provided pivotally mounted at any suitable point on base plate I0 as, for instance, on the post IUI carried by the journal 1,02 and carrying a needle |03 (Figure 9) for transmitting the vibrations induced by the irregularities ofthe grooves of an alreadycut record. In auch case of course, the cutting arm' 34, will either be raised not to engage the record at all or rotated .to a"'positionwhere the lateral feed arm is disengaged from and not A driven by screw 49. The same turn table may b usedfor either purpose.

with reproblems in play-back are quite similar though not duplicate. In play-back, constant pressure is desired as contrasted with the pressure variation desired in cutting.

A large transverse ,inertia is desired rather than transverse rigidly with respect to a feed screw (as in the case of the cutting arm). The

vertical moment should be held at ajminimum as for the cutter. (See Figure 9.)

'I'he play-back cartridge IM is pivoted by knife edges in an angle bracket |08. This mount- -ing is essentially frictionless for vertical movement of the cartridge I, ^while providing for lateral stability and rigidity between the cartridge and thearm. The mass of the arm can be made as large as .desired to reduce the freby the ann must be 'accelerated and the incremental needle pressures may become very large.

In the best'.commercial transcription devices. arms weighing several pounds are used. This produces effective results as long as a perfectly fiat surface is present. Balancing ofthe armmay produce perhaps less than an ounce of pres' sure as long as the surface stays fiat, but as soon l0 as the arm begins to move up and down, the mass thereofproduces, to say, the least, faulty results. In the'present arm, the vertical moment is not pendent upon the transverse moment. 'I'he two are independently controlled. Needle prese. sure is also an independent function. Obviously the lack of interdependence permits a better integrated desisn. a

other important features ofthe cutting head suspension assembly are also, as is now obvious,`

quency ofy arm resonance, which .is that resonance ..20 incorporated in the transcription assembly' obtained where the mass .of the arm works in combination'with the. compliance of the needle suspension and is ordinarily a low frequency.

A substantial portion of the needle pressure is derived from sp 'ma muon of spring-"1 at in the manner previously described.

tached at one end to the lug IIS of the cartridge and. at the opposite end to adjustable bracket' Ilo. Bracket III ishingedly mounted at III and may 'be adjusted for correct spring tension by screw II2 which adjustment may be locked in position by lock nut III'. The entire assembly is carried by the plate lll which is mounted'in arm IIII by screws Il l. P ivoting the cartridge near itscenter of mass keeps the vertical moment low; thus minimising incremental pressures due vto inertial effects when variable record "surface heights are encountered.

A low vertical movement results in tracking ability (ability to follow a groove of a record and the 'ability of the needle to stay inthe groove) when rapid vertical irregularities are encountered, since the resonant frequency (mechanical) in the vertical plane is raised when the moment is decreased.

'I'he spring applies its force in accordance with the principles described above inrelation tothe'` cutting head and in relation to Figure l2. 'I'he rotating alfort thus applied tothe cartridge which in turn results in needle pressure is proportional to the product ofthfe extension of the spring and the sine of the angle o. between the axis of the spring and a line drawn through the pivot point to. the -point where the spring contacts lug I Ql.)

. Change in spring is proportional to the change of the cosine of the angle o. By

choosing the proper angle 'qi for use with a given spring, the elect of the changing 'sine can be made to gancel the en ect of the 'changing cosine 'whe'nirreguiaritles in surface height of the record are encountered.

- 'lhe needle-premise; is therebykept substantially constant. Y

'.In conventional arms. if the resonance 'is to occur at alow frequaicy. the mass of the a'rmmustbemadelarge. Bincethearmissupporte'dby the needleresting on the the needle pressure is dependent on the mass .which `1t nippone.

Counterbalancing or 'spring meanscan be used toobtainadesiredneedlepresaureaslongas no variation inthe height of the record surface is encountered. However, whensurface irregu'-,

landes are the entire mus rre' n (Angle c is angle' The screw IIB for securing the needle |03 may project through' a .slot I I I in the front of the .arm to assist in supporting the cartridge when the needle is not resting upon the record surface. Equilibrium may automatically be established 'I'he entire transcription head or play back care. tridge, its pivots, springs and adjustments may be.un'ited as a single sub-assembly to be made by standard mass'` production methods and mounted as aunit Ain any standard play-back arm. Other replacement, repair and adjustment features will be clear from the priordiscussionj. The turn-table 2| (see Figures;4 and 7) has a pin 9|) resiiiently mounted therein'upon'spring Il whichnormaliy forces the pin-9i] upthrougi'i the perforation 92 to project above the top oi the turn-table.

yieldingly mounted with respect to transverse pressures, willthus insure that' the disk' upo'uf which a record is' to be cut will rotate at all times with the turn-table. When a disk upon whi'cli a record has been cut is placed uponthe turn-' table 2| tobepl'ayed, then it does not matter whether or not it has any perforations for regis.v terin'ggwith the pin 9 0 since the resilient mountiing o: pm so upon spring sI- will permit th? .spring to be depressed by the weight of the record itself. The operation of pin n, therefore,

completely automatic. While the entire assembly has been shown as mounted on the surface of the base plate I0, itv

will be obvious'that the mounting plate I2 may .0 be depressed beneath the surface of the bast plate Ill and that a circular depression may sur round the mounting 'il the said -circular -depres sion having as a center theturn-table 'mounting post I3 sol that thev top of the. turn-table will be virtually. level with the base plate l'ogand .by this. meanstend to prevent any cuttings from the" records or any dust4 or 'needles orother small paraphernalia from impeding the operation of, the various turn-table rotating mechanisms heren inbeforefdescribed.

. Where a depression is not desired, virtually the same purpose may, of course, be accomplished` by causing the ilanges 2ll`of the turn-table' 2i Qto be sulllciently long to almost be in contact with thetop surface of. the-base plate- IO .and thus A record which is to be cut;- sh'ould then have a central perforation .by which do it may be pushed over the tum-table post I3 and reduce the possibility of' any material enterin the operative elements.

Other elements may be combined with and are useful in the operation of the recording unit herein described. Thus in equipment to be used by a non-technical operator every aspect of confusion must be removed from an indicating means.

In the operation of the cutter, the tendency of the cutting stylus is to force the `shavings centripetally.- Occasionally, it is possible for shavings to interfere with cutting action.

Various brushing methods have been attempted as means of clearing the shaving away from the cutting radius without much success. We have used a flexible member or finger 200 (Figs. 2, 8

andi) aiiixed to the cutting arm by the bolt 2M with its tip located beyond the end of the cutter arm in a position where it contacts the shaving. preferably slightly centripetally of the stylus. If the member is of some material (rubber, for example) which has a relatively large coefficient of friction with the shaving, adherence results until the shaving is extended as shown by the dotted lines of Figure 8 to engage the center spindle i3 or the bulkvof shaving already accumulated toward the center of .the record until it is pulled clear of the member by a winding action. The flexibility ofthe member aidsthis clearing operation and causes the tip to return to its normal position after being freed. Because the shaving Winds up on a small diameter, the additional power demand on the motor is kept small. Therefore alternate winding of the shaving and clearing of the iiexible member f-rom the shaving does not occasion any materialchange in power demand on the motor which would cause wows." Obviously, a plurality of fingers may be used if desirable.

It will be noted that by the combination of the foregoing elements, an inexpensive, extremely simple, readily adjustable and easily operable recording mechanism for the lay user has been devised; that the individual elements thereof.

necessarily cooperate with and iniiuence each other while the various stresses present in each of the elements are not communicated from one element to the other.

As h'as also been pointed out above, the relationship among each of the members is such that any variation in response which, in the average recording unit might result in the production of high or low frequency disturbances or noises will vin the present invention not merely be localized 4but actually will be compensated.

i Thus the resilient mounting of the motor and the resilient connection betweenv the motor and the tum-table results in an ironing-out or a smoothing out of the operation of the motor to prevent any disturbing noises from. being transmitted from the motorto the turn table.

likewise, also the lateral feed mechanism of the cutting arm is not directly connected to the motor but is connected to and `operated from the turn-table mounting post so thatadditional elements. of isolation thereof from the motor are present. Furthermore, the cutting head of the cutting arm' is itselfresiliently mounted and so adjusted that variations in turn-table resulting in momentary increase or decrease in relative height thereof with respect to the cutting'head are compensated for by adjustments of the ,cutting head itselfand by automatic changes in the cutting angle of the cutt stylus which permit compensating variations the operation of the therefore. an equalization of the pressures upon the' cutting stylus so that substantially the engiT nal groove depth is maintained.

An important element of the mechanism is the face that the` lateral feed of thecutting arm is not directed by any complicated gearing or cam' arrangements rbut is effected by the ordinary operation of 'a helical screw from the tum-table mounting post causing apawl attached to an arm of the shaft carrying vthe cutting arm to move transversely with respect to the turn-table and thus rotate the cutting arm. v

' In each of the foregoing portions and in the entire constructions there has been described simply the preferred manner of utilizing the various principlesherein setforth and the manner in'which they have been commercially adapted to use. Obviously the various elements hereof may each take different forms, each within ,the spirit of the disclosure herein and accordingly I prefer to be bound not by the specific commer` cial disclosure herein but only claims.

-I claim;

l. In a recording apparatus comprising a turn` table having a spindle, said spindle being rotatable with said turn-table,- a motor, a power connection from said motor to said turn-table, a cutting arm, a rotatable post carrying said cutting arm, a lateral feed arm carried by said post, said spindle driving a screw, a knife edge pawl by the appended on said lateral feed arm engageable with saidv screw, rotation of said screw moving said knife said cutting arm across the turn-table, said knife edge pawl being reslliently mounted on said lateralv feed arm.

2. In a recording apparatus comprising a turnble with said turn-table, a motor, a power connection from said motor to said turn-table, a outL ting arm, a rotatable post carrying said cutting arm, a lateral feed arm carried by said post and a power connection from said spindle to said lateral feed arm for sweeping the cutting arm across Ithe turn-table, 'said post being slidable vlongi- /tudinally in a journal, a platform rotatably cartried by said journal and fixed with respect there-y to against longitudinal movement, a platform carried by said post, the rear end of said cutting arm. being pivoted on said postplatform, a portion of said rear end projecting beyond said pivot, Y

'a link connection between said projecting rear end and said journal platform, andmeans for exerting constant downward pressure upon said post. I v I 3. In. a recording apparatus comprising a turntable, a cutting arm, and amotor, means interl'connecting said motor and said .turn-tableand cutting 'arm for driving the same a v-sh'aped flange secured tosaid arm: a cutting head resil iently mounted in said cutting arm between the free end of said arm and said flange, said cutting head comprising a cartridge, means at one end thereof for carrying a cutting stylus, a knife edge projectionfor' the opposite -and engageable with ii said V-shaped flange, said cartridge A4being vertically pivotable about said knife edge, a tension 'Spring securedat one end to a threaded member mounted on said arm and means on said opposite end of said cartridge engaging the other4 end of said spring, said spring retaining saidv knife edge against the V of said flange.

n 1 1 the'depth of groove to be cut-and which permit edgepawl longitudinally thereof and sweeping` table having a spindle, said spindle being rotatav said threaded niember being rotatable for adjusting theaxis of said end of said spring for c hanging the axis thereof.'

- respecttosaid feedarm.

' a screw 'driven in s spring. 'an opening .in the front ofthe cutting arm, and a screw projecting from the front of the cartridge and engageable with said stylus carrying means for locking the stylus in place in said cartridge, said screw projecting through said 5 front opening of the cutting arm.

4. In a recording apparatus comprising a turntable, a cutting arm, and a motor, meansinter connecting said motor and said turn-.table'and cutting arm forl driving the same a Vshaped 10 thereof for carrying a cutting stylus, a knife edge 15 projection from the opposite end engageable with said V-shaped ange. said cartridge being vertically pivotable about said knife edge, a tension spring secured at one lend to a threaded meinber mounted on said arm and'means on said opposite end of said cartridge engaging. one end of said spring. said spring retaining said knife edge against the V of said flange, said threaded member being rotatable for adjusting the other -5. As'ound apparatus comprising an arm and a head carrying a stylus at-one end, the opposite end of said head being pivotally mounted in said arm and rotatable vertically in a playless bearing,

said bearing comprising means .for preventing 30. horizontal movement of said head with respect to' said arm, means resiliently engaging said head at said opposite end,.and positioning said head with respect to said playless bearing, and means at said stylus carrying end for confining pivotal iriovveineritl of said cutting head within predetermined limits.. f

6. In recording apparatus having a horizontal rotatable-turn-table and a driving means therefor; a cutting arm mounted ona vertical post ranged above said turn-table and meansfor supporting said cutting arm in a position parallel said turn-table; means for sweeping said cuttin arm across the surface of said turn-table; sai i means comprising a horizontal screw rotatable,45

i means on said opposite end of said cartridge enin synchronism with the turn-table and arranged. beneath said turn-table; and a lateral feed arm on said post .extending parallel to said turn-table and beneath said turn-table, said arm carrying a knife edge pawl engageable'with the threads of 50 said screw, said pawl being rigidly laterally integrated with said feed arm and having no lateral compliance with respect thereto, said pawl beingresillently mounted with respect to the vertical plane and having vertical '1. In a phonographic recording iipparatus'comprising a rotatable t table, and a cutting arm,

chronism with said turncompliance with 55 a screw driven in synchronismwith said turntable, a rotatable' post carrying said cutting arm,

a lateral feed arm carried by said post. said post being slidable longitudinally in a journal, a platform rotatably carried by said journal and fixed with respect thereto against longitudinal movement, a platform carried by said post, the rear end of said cutting varm being pivoted on said` post platform, a portion of said rear end projecting beyond said pivot, a link connection between said projecting rear end and said journal platform, and means forexerting constant downward pressure upon said post.

9. In phonographic recording apparatus, a cutting arm, a V-shaped flange secured to said arm, a cutting head res'iliently mounted in said cutting arm between the free end of said arm and said flange, said cutting'head comprising a cartridge, means at one end thereof for carrying a cutting 2b. stylus, a knife edge projection .from the opposite end engageable with said V-shaped flange, said cartridge being vertically pivotable about said knife edge, a tension spring secured at one end to a threaded member 'mounted on said arm and means on said opposite end of said cartridge engaging the other end 4o1' said spring,said spring retaining said knife edge against the V of said flange, said threaded member being rotatable for. adjusting'the axisof said spring, yan opening in the front of the cutting arm, and a screw pro jecting from the front ofthe cartridge and en-r gageable with said stylus carrying means for locking the stylus in place in said cartridge said screw projecting through `said front opening of the cutting arm. l0. In phonographic recording apparatus, a cutting arm, a V-shaped flange secured to said arm.

a cutting head resiliently mounted in said cutting arm between the free end of said arm and said m flange, said cutting head comprising a cartridge, pivoted in a Journal; said-cutting arm being armeans at one end thereof for carrying a cutting stylus', a knife edge projection from the opposite knife edge, a tension spring secured at one end to a threaded member mounted on said armv and gaging oneend of said spring, said spring retaining said knife edge against the V of said ilang'e, said threaded member being rotatable for table, a rotatable post carrying said cutting arm, 60-

alateral feed arm carried by said post, a knife edge pawl on said lateral .feedarm engageable withscrew.' rotation. oi said screw moving pawl longitudinally'thereofl andsweeping said cutting arm across the turntable,- said resiliently mounted-on said lateral -i'eed arm.

8. In phonographic recording apparatus 4com pricing a rotatable turntable and a cutting arm,

pawl being -65 adjusting the other end of said spring for changing the axis thereof. v

1l. A recording apparatus comprising a turntable rotating on a spindle. a cutting. arm, and a motor, means interconnecting said motor and said turn-table and cutting arm for driving the same, said cutting arm carrying a cutting head; a cutting stylus for said cutting head; and a flex'- ible member on said cutting arm engaging the recording surface on a smaller than is engaged by said stylus and sweeping said surface as said turn-table rotates, said flexible member engaging shavings cut by said cutting stylus and holding portions of said shavings stationary. vwhereby rotation of said turn-'table causes the' remaining portions of said shavings to be wound up on said spindle.

.PAUL s'rEAD only.V

radius thereof

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