US2670962A - Phonograph needle - Google Patents

Description

March 2, 1954 F. C. HOLTZ, JR

PHONOGRAPH NEEDLE Filed April 20, 1950 .Wederz' Patented Mar. 2, 1954' 2, 70,962 HO GK NETEJBPE: ite e eke m Jr -tee h Il assi n!!! 2 1! eibe tfeeeeeseti e.

Application. Aprfl20 1950, Qeria} N9. 151,969 1.3 (01,

white inven i n elateste m no ra h needleml' mer articu a e henvetateh e e: having a flexible .seetinne m ov n the .9m;- nllianee o the needle, eis ne dbei g c stzue ed he prot et. t fl ible seetien g a r t bzzeake t One-"featur a the invent en e th t t 9 tides en: mpflme pho o aph eedle: anq er mature of the: mye ioe sha i P &- p m eemn e e l i g e; exi e ee n fer re idinee substan a amou t 01 Ye" e1 horizontal eemnl ee e and aving mean pre ectin the. e ibl ee i n a eine WeeR eQ e f. the: eetuee ef: inv nti n ie the? t flexible eeetion eem me a m; W 0 e0 speeee el s exte e when th .Qeeh t e h nk Qt t neee v ee elw t e eve e e? on i u nale ie er qi"; il-1: ne he feete r 91 the inventie i t at at Re enee ai W en the onpq 1 f s qlm eiiethe r said e ete the- 19% e ee eeeine few at eesfie e flexible;e nneetmes r et l eb e w yeta furthe ieetu e f he iev' m Eh shank 59- than? the QOQQQQ e parall l: he the e er lee-"we fleeible emi ti e i rise t e tiv pteierebli hem a tetlkp ee i meme;- iJ Fi1 e and??? mum thickness of the order of 0.01 11105,,

Q-Plee t n eand a a t -p i) e e tign. will be apparent. i em the iollbwine Speci'fi: eetien and fipom the drawings, in which:

Fig.1 is a, iregmentary side elevation of' e. t'qne gnm-Ieaprymg a; neegi leucenetmctecf in. ecc ragit e wt he 'nventiem. the tipof the needle. engaging het ieee re er i- F-ig', g' ;is'. an enlarged side. elevational view of t e nee e f- 'Ei 11 remq e fiem t rm; ie 3- ise l ee twn i w Ofthe me u? owe-2 Qkine r the H er- 0f? .Figflfilis a fragmentary sideeleva'tibxiali View 0i a mddifi m needle; and

i e s de el vafiqne ew Q? the ne dl 15 li q inef f om h le t the ee Ii the newd s f s un rom Ph ne'- grekpf r record; petrtien'iafly" from a} iaterell'y cut iecord 'whieh the undulations representmgtfie rattle: 0t. monographs which emplpy a; rigid dle. In; additiejn', a needle. havine'suchverticali mpliance willelso lessen sflzfialie'd ---need;1e tent" and other. sunfacer nuises which: reaeh the. ear directly item; the needle without being. trans-q v mitt-ed theme-1e the amplifying ystemassqeiateel with the phonograph. To achieve; satisfactory vert ea lcemel-ieneeetzhe needle w v eh transmits vibrq. inn tn the 61YI123120F other. translating; de;-' e nertienwhieh is thin atmane' substantially 1 eshank. efitheneed le. It des mhl t0: pt vide means to pr tect sucha flexible pe tie I ene e ka e or detonmation he eventthe nee le is," mppee .112130; the netiord I gurfaw Q3 1. ithershoqlset I have-heretel-r for inY n-te nhone teen needl s havin a: uard: de e- 'D J .e fi the needl structure and wh ch er q meteet t e needl ee in S ch eak e. defierm ion, need es 6 thi shame:- elaime i n e ndine v 3-. 93327 filed Ap l 1 .1948; ate 2 553 882; Se iefl No 51:62: ed Au us v lees, nd Serial: Ne- 5. ;8'5 fi d;- eetebe flt 18% Y- In the e tiethen attempts have beenmede-tq pro ide phonperenhneedles he -ineventi a i com: F e -me by efise fiine the recerd en in t p the needle at the end gf' at nelativelylong spring; member whi h; extends e cen iderable distance finom the axis: of theshanle 01' the needle; A dis; adyantage ofl such: an, arrangement is that when? the? recqid': engaging; tip?- spaeedi a; considerable; distance f rom the shen'kiw change mm the angle of the: tone caluees a substantial ehange in the; angle atzwmch the needle ti p' engages the; groove 3 will be considerably different than when ten or twelve records are on the turntable. Furthermore, such an arrangement locates the center of gravity of the needle a considerable distance from the shank, and the needle has an undesirable action in responding to certain forces, the inertia effects of this arrangement causing sluggishness.

Another desirable feature in a phonograph needle is a considerable degree of horizontal compliance, particularly in the direction of the record groove. Prior to my inventions needles which provided a bumper to protect the flexible portion against breakage had only limited horizontal compliance because the extension or foot which provided the bumper added considerable additional mass to the needle; and other needles having a flexible portion in the form of a horizontally extending loop, while providing more horizontal compliance, have had undesirable features in that forces in the direction of needle travel develop torque in the needle.

I have devised and am herewith disclosing and claiming an improved phonograph needle which possesses desirable advantages of vertical and horizontal compliance together with means for protecting the flexible section without any of the disadvantages noted above, and which is further advantageous in that the needle is so constructed that it has no portions which extend outwardly away from the shank and the mass of the needle is no greater than that of an ordinary rigid needle having no flexible section.

Referring now to the drawings, in Fig.1 a tone arm It) carries a needle generally designated at II in a chuck (not shown), and the needle rides in a groove upon the surface of a phonograph record 12. The needle is responsive to undulations in the groove and transmits them as vibrations to a crystal or other translating device.

In conventional operation the vibrations are translated into electrical variations, are amplifled, and are reproduced by means of a speaker or other transducer. In Figs; 2 and 3 the needle of Fig. 1 is shown enlarged and removed from the tone arm chuck. The needle comprises an elongated shank and a terminal tip portion l9. The shank has an upper relatively rigid portion l3, which is generally cylindrical in shape and a flattened portion I4 which extends on the upper end of the shank along one side for a substantial portion of the length of the shank. This flattened portion serves to indicate the front side of the shank so that the needle may be properly positioned in the tone arm chuck, and in addition the-flattened portion cooperates with the holding end of a set screw or other holding device on the tone arm so-that the needle may be held immovably in the tone arm chuck.

The shank-also includes a lower flexible portion formed by a plurality of closely spaced narrow parallel slots l5 and [6, each extending more than half way through the shank generally transversely of the longitudinal axis thereof. The slots are cut on opposite sides of the shankand are cut in the direction of the record groove when the needle is in operating position, and a flexible connecting strip I1 is provided between the slots. Preferably, the slots are cut in front and rear walls of a widened portion 18 having flattened side walls 18a and [81). As shown in Fig. 3 the distance between the flattened sides is less than the width of the shank above the widened portion, and as shown in Fig. 2 the dis tance between the front and rear walls of the widened portion is no greater than .twieethe because of the flexible strip l1.

width of the shank above the widened portion. Each slot has a thickness of the same general order as the thickness of the connecting strip I1, and I prefer that each slot and the strip each have a minimum thickness of the order of 0.006 inch and the maximum thickness of the order of 0.01 inch. In the needle of Fig. 2 the slots may each be 0.008 inch thick and the strip I! may be 0.0115 inch thick. I prefer that the slots be cut at an angle of between 65 and 75 to the axis of the shank so that the connecting strip is substantially parallel to the record surface when the needle is mounted in operating position. In most conventional tone arms the needle extends at an angle of approximately 21 to the record surface. This construction also provides a relatively long connecting strip H without adding to the mass of the needle. I also prefer that the bottom slot l6 be shorter than the top slot 15 so that the portion shown at 20 in Fig. 2 is thicker than the portion shown at 2! in said Fig. 2. With this construction, upon abnormal flexure of the needle (as for example if the tone arm is dropped) the relatively thick portion 20 will prevent the tip IQ of the needle from being bent out of line with the axis of the shank. In the event the tone arm is dropped the upper slot 15 closes momentarily at its outer end and the thin flexible strip i1 is put under tension like a spring connected to the portion 2|. When the abnormal pressure is released the flexible strip returns to its normal position as shown.

A needle constructed in accordance with the invention possesses excellent vertical compliance Satisfactory lateral compliance is also present in the needle because of the flexible strip, and consequently the needle tracks properly in the record groove and has a relatively high output. Compliance to horizontal forces in the direction of the record groove is obtained due to the relatively thin portion 21, and the good overall compliance of the needle insures a low level of surface noise and needle talk. In addition, the normally spaced portions at the outer ends of the slots which are adapted to abut in the event the needle is droppedor is subjected to other abnormal pressure, provide means for guarding against breakage or deformation of the flexible strip without adding any mass or bulk to the needle. In fact, a needle constructed in accordance with this invention will have less mass than an ordinary rigid needle because a small part of the needle is removed when the slots are cut. A needle constructed in accordance with the invention will provide good pickup at desired audio-frequencies and will attenuate frequencies in excess of 6,000 cycles per second.

Referring now to Figs. 4 and 5, the shank 23 of the needle may have flattened sides 24 near its lower tip extremity 3i, and a lower flexible portion is formed by a spaced pair of parallel slots 25 and 26, each extending more than half way through the shank from one side thereof generally transversely of the longitudinal axis thereof. A center slot 21 extends from the other side of the shank between the pair of slots to provide two spaced parallel flexible connecting strips 28 and 29. Preferably, the bottom slot has a rounded end facing in a direction counter to the direction of record travel, and the center slot 27 preferably is shorter than the upper and lower slots to provide a relatively heavy solid portion 30 which may act as a bumper in the event the needle is dropped. In this needle, as;

gara es Welles inthe needle-of-Fig2, the flattened por tion. is not necessary but by providing such a flattened. portion better lateral complianceis achieved. The needle of Figs. 4 and 5 hasthe same advantages as-the needle of Fig. 2 but I prefer the needle of" Fig. 2 because it is more simple to manufacture.

While many variations may be made-in the dimensionsof the needle, Ihave foundthat a suitable needle' may have a shank with a diameter of I a-inch, and the flattened portion ldof'tlie needle oi Fig. 2 may have a width of ilgllllincli at its widestpart. Inthe needle of Fig.2, the portion lt may be 0.025 inch thickand the portion 20 may bra- 0.030- inch 7 thick. 1 The widened poition l8 near the tip end of the needle may be of the order of inch long and may be of the order of 0.030 inch wide.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement maybe made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A phonograph needle of the character described comprising: a straight elongated shank having an upper relatively rigid portion and a lower flexible portion formed by a plurality of closely spaced narrow parallel slots, at least some of which extend more than half way through said shank generally transversely of the longitudinal axis thereof, at least one of said slots being on the opposite side of said shank from another of said slots to provide at least one flexible connecting strip therebetween; and a terminal tip portion extending from the bottom of said shank.

2. Apparatus of the character claimed in claim 1, wherein said slots are cut at an angle of between 65 degrees and '75 degrees to the axis of said shank and said connecting strip is substantially parallel to the record surface when the needle is mounted in operating position.

3. Apparatus of the character claimed in claim 1, wherein said slots are cut in front and rear walls of a portion of the shank having flattened side walls, the distance betwen the flattened sides being less than the width of the shank above said portion, and the distance between said front and rear walls being no greater than twice said width.

4. Apparatus of the character claimed in claim 1, wherein said slots are equally spaced from each other, each slot and each connecting strip having a minimum thickness of the order of 0.006 inch and a maximum thickness of the order of 0.01 inch.

5. A phonograph needle of the character described, comprising: a straight elongated shank having an upper relatively rigid portion and a lower flexible portion formed by a plurality of closely spaced narrow parallel slots each extending more than half way through said shank generally transversely of the longitudinal axis thereof, at least one of said slots being on the opposite side of said shank from another of said slots to provide at least one flexible connecting strip therebetween and said slots being cut in front and rear walls of a widened portion of the shank having flattened side walls, the distance between the flattened sides being less than the width of the shank above said flattened portion and the distance between said front and rear walls being no greater than twice said width,

each slo'thavinga thickness or the. same orderi'as the thickness of said. connecting strip; and a terminal tipportion extending from" the bottom of said shank, the inassof the needle beingsub stantialiy equally distributed about its. longi tudinal axis. 6. Aphon-ograph needle of the characterde! scribed, comprising: an elongated shank having upper relatively rigid. portion and a lower flexible: portion formed by alpair of. parallel slots each extending more than halfway through said shank from opposite sides =thereoiigenerallytransversely of the longitudinalaxis thereof to provide a flexible connecting strip having a thieknesspf the order 0130.006 inch: and a:-maximum thickness of the order of 0.01 inch, one of said slots being cut in the direction of record movement; and a terminal tip portion extending from the bottom of said shank.

7. Apparatus of the character claimed in claim 6, wherein the shank is straight and the lower slot is shorter than the upper slot to prevent bending of said terminal tip.

8. Apparatus of the character claimed in claim 6, wherein the shank is straight and said slots are cut at an angle of between degrees and 75 degrees to the axis of said shank and said con- 7 necting strip is substantially parallel to the record surface when the needle is mounted in operating position, and wherein the thickness of each slot is substantially equal to the thickness of the connecting strip, the mass of the needle being substantially equally distributed about its longitudinal axis.

9. A phonograph needle of the character described, comprising: an elongated shank having an upper relatively rigid portion and a lower flexible portion formed by a spaced pair of parallel slots each extending more than half way through said shank from .one side thereof generally transversely of the longitudinal axis thereof, and a center slot extending from the other side of said shank between said pair of slots to provide two spaced parallel flexible connecting strips; and a terminal tip portion extending from the bottom of said shank.

10. Apparatus of the character claimed in claim 9, wherein the center slot is shorter than said pair of slots to provide a relatively large intermediate portion interconnecting said flexible strips.

11. A phonograph needle of the character described, comprising: a straight elongated shank having an upper relatively rigid portion and a lower flexible portion formed by a spaced pair of parallel slots each extending more than half way through said shank from one side thereof and generally transversely of the longitudinal axis thereof and a center slot extending from the other side of said shank between said pair of slots to provide two spaced parallel flexible connecting strips, said slots being cut in front and rear walls of a portion of the shank having flattened side walls, the distance between the flattened sides being less than the width of the shank above said portion, and the distance between said front and rear walls being no greater than twice said width, and said slots being equally spaced from each other, each slot and each connecting strip having a minimum thickness of the order of 0.006 inch and a maximum thickness of the order of 0.01 inch; and a terminal tip portion extending from the bottom of said shank, the mass of the needle being substantially equally distributed about its longitudinal axis.

12. A phonograph needle of the character described, comprising: a straight, elongated shank having an upper relatively rigid portion and a. lower flexible portion formed by a plurality of slots extending partially through said shank generally transversely of the longitudinal axis thereof, at least one of said slots being on the opposite side of said shank from another of said slots andsaid slots overlapping to form at least one flexible connecting strip therebetween, the mass of the needle being substantially equally distributed about its longitudinal axis; and a terminal tip portion extending from the bottom of said shank.

- 13. Apparatus of the character claimed in claim 12, wherein said slots and said strip eachhave a minimum thickness of the order of 0.006 inchand a maximum thickness of the order of 0.01 inch.

FREDERICK C. HOLTZ, JR. f

References Cited in the file of this patent UNITED STATES PATENTS

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