US2452304A - Phonograph needle - Google Patents

Description

Patented ct. 26, i948 UNETED STATES `ATNT OFFICE PHONOGRAPH NEEDJ William H. Hutter, Wheaton, Ill.

Application August 19, 1947, Serial No. '769,476

' 's claims (ol. zwi- 38) 1 This invention relates to improvements in phonograph needles.

It is an object of this invention to lprovide a phonograph needle of superior fidelity of tone reproduction. One criterion of fidelity of tone re production is the wave shape of the signal voltage as observed on an oscillograph. If a needle is played on a frequency record in which the groove is modulated in the form of a sine curve, any departure of the wave shape from a sine curve indicates a corresponding lack of delity at that particular frequency.

This distortion of the wave shape is considered to be attributable to various causes. For instance, a given needle may have insufficient compliance to enable it to follow the record groove. `Another cause of distortion appears to be the resonance of the tone arm, and other acousticalresonances, such as crystal resonance-or system resonance.

Another criterion of fidelity of tone reproduction is the absence in the lfrequency response curve of peaks that are attributable to acoustic characteristics of the needle. These peaks indicate the presence of an increased signal strength at certain frequencies, which-is an undesirable f factor in musical reproduction. and are considered yto be attributable to resonance.

A further object of my invention is to provide a phonograph needle having the proper compliance in combination with sufficient mechanical strength to enable it to be subjected to the usage which is often encountered in record changers, in which the needle and Vtone arm are dropped through a distance of one to several inches on successive records. f

Another object of this invention-is to provide a needle which is relatively free from needle scratch. The term needle scratch refers to the extraneous noise transmitted through the needle, the pickup, the amplifier and the speaker, and is considered as being due to the presence of hard particles or other surface irregularities inthe record which impart an irregular movement to the needle over that imparted to the needle by the groove. Although these. irregular movements are of muchsmaller magnitude than the motion of the needle which is caused by the modulation of the groove in sound passages-of-,medium volume and medium frequency, the ratio of noise to signal increases considerably in passages of less volume and of higher frequency. Under such conditions, the needle scratch is more readily observed audibly but at all times it is considered to be objectionable.

A furtherobject is Vto provide a needle which is relatively free from needle talk. The term needle talk refers to the sound produced by the needle in the air directly, due to its vibration. This sound is sometimes the musical sound pro'- duced by the needle point following the modulations of the groove but at other times it is a noise which can be attributable to a chattering of the needle due to its inability to follow the groove or due to the presence of tone arm resonance or system resonance. y,

I have found that the above objects canA be attained by fabricating the needle, either in its entirety, or in part, from certain organic plastic materials, such as a certain type of nylon.

Fig. l is'an elevation showing one embodiment of my invention;

Fig. 2 is a elevation showing a modified form of the needle shown in Fig. 1;

` Fig. 3 is an elevation showing another embodiment of my invention;

Fig. 4 is a view taken along line 4-4 of Fig. 3;

Fig. 5 is an elevation showing a modified form of the needle shown in Fig. 3;

Fig. 6 is an enlarged elevation, partially in section, of a portion of the needle shown in Fig. 5;

Fig. 7 is an elevation of still another embodiment of my invention;

Fig. 8 is an elevation of a modified form of the needle shown in Fig. 7;

Fig. 9 is a sectional view taken along line 9 9 of Fig. 8; and

Fig. 10 is an elevation of a still further embodiment of my invention.

With reference now to the drawings, Fig. 1 shows a straight phonograph needle comprising a chuck engaging'portion I3, a stylus portion I2, and a connecting portion I3a which connects the stylus portion andv the chuck engaging portion. The portions I3 and 13a are both formed from nylon and are integral with each other, and together comprise an elongate body member designated generally by the reference numeral I I. The stylus portion I2 is in the formof a separate stylus meml.ber and projects from the lower end of the connecting portion I3a, to which it is suitably secured. The chuck engaging portion 4I3 is adaptn ed to be received within the usual chuck of a phonograph pick-up.

The stylus portion I2 may be formed of sapphire, or of a suitable metal or metal alloy, so as to provide a hard, long wearing stylus capable of playing several thousand records. The stylus is in the form of a cylinder terminating-in a conical portion, the apex. of which may be somewhat rounded, the rounded apex having a radius from needle of Fig. 2 is good for only a few plays, butv may be manufactured at considerably less cost than the needle of Fig. l. The upperportion l of the body member I4 is adapted to be received within the usual chuck of a pickup. The lower portion serves to connect the' chuck engagingpor-1 tion |6 and the stylus portion |5 and constitutes a connecting portion i3d. In order to 'achieve better Wearing qualitiesof the stylus l5, it is considered4 preerableto- -form the needle rfrom a nylon' whichjincludesasuitabie filler, such asfaluminum powder.

Figs. 3- and-'24 illustrate'ia further embodiment of this invention. IThe needle-shown therein comprisesiai nylonbo'riy member |"|"ha', ving a metal shank |8i Them'etal shankl comprises aportion' {Uwhich is adapted to be' receivedw-ithin-the "usualiplokup chuck, arrdiaportion' of reduced diameter which is embedded in the upper portiorrv 2 'ofi the nylon body* member 1. Tli'e'- nylon bofdy member |1 is' preferably injection molded, and;the'sliank` lltakes the 'form of an insert, the nylonV being molded around the portion 20 and the 'lower 'extremity of portions' Ig. The portion 23 may be knurled, as indicatedA in; the drawings; or'der to providearmor'eisecure association ofthe parts. y

That portion of tl'ienylon body-` member' I1 which is below the end of'thepoition of the metal shankK isfa'll"A nylon', 'and 'can' be referredy to as thenylonA connecting' portion 22. The: porfrom the under surfacetlier-e'of. It'will be* ob- -servedf that this-'needle ifsa eharocterizedi by albend,

indicated generally by reference numeral 2W, the

'bendi being formed'in the nylonl connecting-L pornon 22. v

The portionlofoi" the metalli sliazil'r IIB- may be `slabbed as indicatedI by the reference; numeral 25 in`| order tofp'rovideI proper orientationof the needle when the1 slabbe'd" portionV |91 is engaged by fthe set' screw oftliefpickup chuck'. lIt Will be observed that the'nylo'n body member |1 through- 'outth'e greaterfportion oi`- its length istapered fbothl in-thicknessand` Width. The cross section ofthe upper portion '2| oifthenylonlbody member isfgenerally circular and itmerges intothe rectangular cross sectionoi the nylonconnecting portion 212;

"Inthe embodiment show-n in Figs- 5 and 6,

instead of being'v provided with agradual bend,

as in Figs. 3 and 4, the nylon bodymemb'er 26 visf'provided' with am abrupt bend designated generally' by thereference numeral-341 The needle ofFigs. and 6 isf-provldedwith ametal `shank 27? which is similar toi-"the metalsha'nk l'Y o'f Figs. 3 ande'. The metal'shank I8 comprises a slabbedg'portfion '28' adapted to 1 be' received'-V within tlieusuarlE pick-'upv chuck; and" affknurled portion noefsoi 29 of reduced diameter which is embedded With-- in the upper portion 30 of the nylon body member 26. The remainder of the nylon body member may be identiiied generally as the nylon connecting portion 3|', but the abrupt bend 34 divides the nylon connecting portion 3| into a. substantially vertically disposed part 32 and a substantially horizontally disposed part 33. The upper portion 3|! is of generally circular cross section; the horizontally disposedl part 33 is of generally rectangular cross section; and the circular cross section of one merges into the rectangular cross section of the other in the vertically disposed part 32. The nylon connecting portion 3| is tapered both in length and width. The abrupt bend 34 serves to increase the flexural vcompliance of they nylon connecting portion 3| in a vertical plane.

Asshown in Fig. 6, the substantially horizontally disposed part 33 is provided with a bore 31 which partially intersects' the Dupper surface. of

the horizontally disposed member 33lftoprovide ari aperture` Sit-oi 'smaller diameter' thanw the bore. A record'- engaging stylus sissecur'ed in the bore 3-1 by' a suitable: cement 42u?, andthe dimensions ofthe bore and of" the stylus;- aridi the mahnerof associating the twose'cureim are substantially the same as pointed outfin connectionlwith'v my copending application Seriall NmV 696,701, led Sep'- tember 133, 1946. In general; the-bore is of some'- what smaller diameter` than the diameter (of the cylindrical portion of thestylus- 39'.v 'l'he cylir1d`1ic':a`.ly portion is'f' forced 1 into the bore; and the resilience and' toughness or the nylon',` assistedfby-tire 'cement 4o,- cause the cylindrical portion to be *gripped very firmly.. 'The nylon body member 26 is preferably' injection molded aroundv the metalV 'shank y2?.

The needleshown'- in: ligi'fi comprises a... nylon body ll and al metal shank il?.V V"llfhe" nylonibody member 4| comprises an. upper portion. 432 in Whichfav reduce'd -khurledportion'- 'ot the' shank i2` is-embedded, ando nylon.- connecting portion 4'4' which' issubstantially norizontauy disposed, and wniehrapproximates' in: dimensions andsnape, the dimensions. arid shape. ofthe horizo'r'ital`v part 33 of the needleiof1igs.-.51anc` Astylusi isisecured in: theforwardi end` ofl the nylon: connecting portion 445 inmuclr the same'- manner' as pointed kout in` connection with'- the .needles of Figs. 5 and '6.

Figs. 8' andi` @illustratorl a needle'. somewhat simi'- lar t'otheneedle-oi Fig. 'hinsofar as 'dimensions and operating characteristics 'are concerned.

This needle comprises a nylon/body member,

andi al. metal shank 111.y the lower :reduced roortionl oi which -l'sern-be'ddedl in the' upper portion 4'8 of a nylon' body 'member $6. The nylon connecting.' portion 1491 -whioh1 isl subjected to'A the iiex'u'ral"and'- torsional vibrations caused Vby Ythe engagement of the` needle stylus 5|lwith 'the record groove, i'slof l'ess thickness than thenylon connecting' portion l'M1 ci Fig'. '7l

The needle of-1 Fig. 1f0'1is similar to' the'rieed-le of Figsjand 6`, with3 the.v exception: that instead of the' metalisha-rik 212,V the upperportion'or chuck engaging'portion 52T or theneedle' isforrnedlfrom nylon, and is integrarwithA the remainder ofthe needle. The nylon `body member is designated generally byt-he reference' numeral'- 5| andincludes, i'n addition to the chuck engaging' portion 5'2, elifsubstantia-lly vertically' disposed part 53"', anda substantially'horizontally disposed; part 54. A stylus 55 is inserted toward the forward or outer'en'd ollpa-rty l'5|-iii-thesamemanner as 4'pointed 'out in connection with the preceding A taken of the -fact that the kdrawings "(except for Fig'. 6) are scaled to fabouthfour times -the 'actual size. For instance, the needle of Fig. l is about 5/8 .of an inch long and .070 inch fin diameter.

4It will be apparent that lthe desirable characteristics which flow from the use 'of nylon in a phonograph needle are obtained when at least a portion of the nylon body member comprises a connecting portion: that is, a compliant unstiiened portion which can be subjected to flexural or flexural and torsional strains. The length ratio of the nylon connecting portion to the needle as a whole can vary anywhere from about one to eight up to unity. For instance, in Fig. 7 the length of the centroidal axis of the needle as a whole is designated by the reference character A, and is approximately 3/4 of an inch; whereas, the length of the centroidal axis of just the homogeneous portion is design-ated by the reference character B, and is approximately 1/i of an inch. Thus the length ratio is approximately one to six.

The corresponding dimension B in the needle of Fig. 8 is approximately 35 of an inch, so that the length ratio of that needle is approximately one to eight.

The nylon connecting portion of each needle shown in the drawings is elongate; that is, its length is greater than either its average width or average thickness. However, where vertical compliance is primarily desired the width could equal or exceed the length, and where horizontal compliance is primarily desired, the thickness could equal or exceed the length. The exact proportions of length to thickness or of length to width, and the degree of taper, if any, may be varied according to the characteristics desired.

The nylon body members of the needles shown in the drawings may be formed from these types of nylon designated as FMlOOOl nylon and FM3001 nylon (formerly designated as FlVll nylon and FB/I3 nylon, respectively). These types of nylon, as far as I know, are manufactured and sold only by the E. I. du Pont de Neumours and Company, of Arlington, New Jersey. I prefer to use FM10001 nylon, which in its natural unlled and unpigmented state is a translucent white in color. However, the needle of Fig. 2, as pointed out above, preferably embodies an aluminum ller, and the needle of Fig. 10 is preferably formed from a black FM10001 nylon.

The metal Shanks, where used, are preferably of aluminum alloy.

The word nylon as used herein, refers to a substance sold by E. I. du Pont De Nemours dz Co. which is defined by them as a generic term for any long-chain synthetic polymeric amide which has recurring amide groups as an integral part of the main polymer chain, and which is capable of being formed into a filament in which the structural elements are oriented in the direction of the axis. Nylon may otherwise be defined as a fiber-forming polymer including synthetic linear condensation polyamides formed by reacting organic diamines with dibasic acids or with the amide-forming derivatives of dibasic acids, and polyamides formed from polymerizable amino acids.

The organic plastic material of which the body membersv of the needles herein disclosed are formed may also be identified by 'certain physical characteristics set forth below. FM10001 nylon and FM3001 nylon have those physical characteristics. As used herein, the term nylon having substantiallythe same physical characteristics as FM10001 nylon designates nylon, including .FMlOOOl nylon, having physical characteristics which fall within the ranges set forth in the following tabulation.

Test Characteristic irggfl. Values Designation Specific gravity 1.09 to 1.16.`

low temperature D560-43 Not less than 400 F. Deformation under load. D62143 Nclizoniore than 5% at Stilness in flexure D747-43T... 150,000 to 300,000 pounds per square inch at 77 F. Flexural strength D650-42T 8,000 to 15,000 pounds per square inch at 77 F. Heat distortion temper- D648-44T Not less than from 130 F. ature. to 171 F. for l0 mils deflection at 264 pounds per square inch M50 to M Rockwell. Hardness D-22943 $4" ball; minor load l0 kilograms; major load 100 kilograms.

FM10001 and FM3001 are made in accordance with the disclosure of United States Patent No. 2,130,948, issued September 20, 1938, to Wallace Hume Carothers.

The use of the iiller or pigments in combination with an organic plastic material having physical characteristics falling within the ranges set forth in the above tabulation shall be included in the term having physical characteristics essentially the same as FM10001 nylon even though the use of such llers or pigments would increase the specific gravity beyond the range specified.

This application is a continuation in part of my copending application Serial No. 590,329, filed April 26, 1945, and the subject matter thereof, insofar as it is consistent with this application, is hereby incorporated by reference into this application.

I claim:

1. A phonograph needle comprising a stylus portion, a chuck engaging portion, and a portion connecting said stylus portion and said chuck engaging portion, said connecting portion being formed from nylon having substantially the same physical characteristics as FM10001 nylon and being of a length of at least one eighth of the total length of the needle.

2. A phonograph needle according to claim 1, in which said stylus portion comprises a separate stylus member inserted in said connecting p0rtion at substantially an end thereof.

3. A phonograph needle according to claim 1, in which a part of said connecting portion is disposed at an angle with respect to said chuck engaging portion such that when said chuck engaging portion is gripped within the chuck of a pickup cartridge, the axis of said part will be disposed substantially parallel to the plane of a phonograph record when the needle is in cooperative relation thereto, and in which said stylus portion comprises a separate stylus member projecting from a face of said part.

4. A phonograph needle according to claim 1, in which said chuck engaging portion comprises a metallic member, a part of which is embedded in said connecting portion.

5. A phonograph needle comprising a stylus portion, a vchuck engaging portion, and a portion A phonograph needle comprising a kstylus V-porton, a chuck engaging fp'ortion, and a. .por-tion coz-meeting said stylus portion and `said .chuck-en- 'igaging portion, said `connecting fportion Lbeing formed from FMBUGI nylon and being fof afl'ength nof `at ieastone eighth `of the total `length of the needle.

7. A phonograph needlezcomprising-,a-body portion formed from FMIOOOI nylon, a metallic `vchuck engaging portion having Aa portion embedded in said -nylon body portion, and ,va-'stylusnsented in s'a'id nylon body -portionat .substantially the end thereof `remote from .said metallic chuck ien portion, isa-in fnylon ibody portion "being of a length of at least one eighth of the total flengthaof the fneed'le `and serving to Connect :said

vNo references oited.

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