US2173763A - Phonograph needle - Google Patents

Description

Sept. 19, 1939. A. J.,o| sEN PHONOGRAPH NEEDLE Filed Aug. 10, 1936 Y Patented Sept.- 19, 1939 UNITED STATES PATENT Price alvarez.`

PnoNoGnArn NEEDLE Arthur 3. Olsen, Chicago, Ill. Application Aegust 10, 1936, serial No. eaoss i claim. (oi. 274-38) invention contemplates and provides a needle, for cooperation with lateral-cut records, which is especially and peculiarly adapted to give excellent and long continued service in automatic E phonographs.`

It is the general object of the invention-to provide a needle so constituted and constructed as to: reproduce with delity, and substantially constant volume, the very high and very low, as well i@ as the intermediate, sound frequencies recorded. by a record with which it cooperates; withstand the repeatedl shocks resultant from its being dropped upon successive records; utilize the abrasive 'action of present-day records to keep itself in good working condition; and minimize destructive wear on the sides of the record grooves in which it operates.

A specific object of the invention is to provide a needle, preferably consisting of but two ele- 'go ments (i. e., a hard tip and a shank), which is 30 forming any volitionaloperation other than that of welding or of fusing a hard tip to a relatively much softer shank. p

Another object of the invention is to'provide a needle which, intermediate its ends, is swaged 35 in such a manner as to (a) stiffen it against ilexures at right angles to its-path along a record groove, and (b) Aindex the curved knife-like record-engaging. edge of the needle tip and thus facilitate the proper placement ofthe needle in 40 a. pick-up or sound box.

Other features, objects and advantages of my invention will appear from the following detailed description, wherein reference is made to the accompanying sheet of drawings, in which- Figure 1 is an elevational view of a needle shank and its tip as they appear Vbefore the latter is welded or fused on and into the former; l

Figure 2 illustrates the same parts as they appear immediately after having been welded or fused together;

Figure 3 is an elevational view of the needle as it appears immediately after the swaging operation;

.55 Figure 3 1; is a view Simil? GP Figure Z3-.but

showing the needle as it appearswhen turned 90 degrees from the position shown in Figure 3;

Figure 4 is an elevational view of the needle as' it appears after being ground to finished form;

Figure 4--a is a-viewl similar to Figurefl but 5 showing` the needle as .itv appears when turned through 90 degrees from the position depicted in- Figure 4;

Figure 5 is a transverse section taken onthe line 5--5 of Figure 4; 10

vFigure 6 is a transverse section taken on the line 6--6 of Figure 4;. and

Figure 7 is a transverse section taken on line '1 -1 of Figure 4.

The scale of Figures 1 to 5, both inclusive, is15 eight to one. The scale of Figures 6 and 7 is sixteen to one.- l

Similar characters of reference: refer to similar parts throughout the several views.

Referring rst to Figure 1, reference numeral i denotes a needle shank and numeral 2 denotes a hard pellet which is to be set on and into the adjacent endv of the shank by a welding or fusing operation.

Shank l consists of a stiff wire or small diameter rod, of appropriate length, which,` for' reasons presently to be explained, is formed from an a1- loy comprisingessentially a minor percentage of beryllium and a major percentage of copper. The

preferred formula for such beryllium-copper alloy l,

is: beryllium 2 to 21A%; nickel 1/4 of 1% to V2 of 1%; a trace of iron, less than 115 of 1%; copper the remainder.

Bellet 2 preferably is formed of the so-called iridium of commerce, this being an alloy, commonly found in fountain pen nibs, which usually comprises some or all of iridium, platinum and osmium, the alloy of the pellet 2 having a melting point very`much higher than. the melting point-of the beryllium-copper of the shank l. The pellet preferably is approximately spherical, and is characterized by a multitude of minute surface scratches or ssures which inevitably arev present when such a pellet is reduced to approximately spherical shape by ordinary means.

With the shank i held by or against one of the electrodes of a w/elder," and with the other electrode firmly pressing the pellet 2 against the adjacent end of the shank, a current is passed between the electrodes to melt the beryllium- 5o copper which engages the pellet, and 4thus to perinit the pellet to be set into the adjacent end of the shank and the melted copper beryllium of the :hank to occupy the scratches and fissures of the .embraced surfaceof the pellet (see Figure 2). 55

Thus a permanent physical union is established between the pellet and the shank, a union which is surprisingly strong and tenacious because the melted portions of the beryllium-copper shank (and those portions thereof which approximate melting temperature in the welding or fusing operation) become extremely hard as the consequence of mere cooling, in air, to room temperature. This phenomenon, which I believe to be peculiar to beryllium-copper, is largely responsible for the great strength and excellent sound reproducing qualities of the needle of the present invention.

@The region of the shank I which lies adjacent to the applied hard pellet 2, is next subjected to the action of swaging dies to give litthe conformation depicted in Figures 3 and 3 a, i.` e., to provide it with the lateral stifening ribs 3 3 and the fore and aft wings 4 4. .The Wings 4 4 have as their principal function the indexing ofthe curved edge with which the needle tip is provided by suitable grinding, as will presently be explained. Ribs 3 3 lie within projections of the cylindrical surface ofthe shank (see Figures 3 a,A 4 a and 5), whereas wings 4 4 exy tend outside of similar projections of the cylingical surface of the shank (see Figures 3, 4 and After the swaging operation, the needle tip is carefully ground to the conformation depicted in Figures 4,4 a, 6 and '7. It then has a curved knife-like edge 5 which occupies a plane` common to` both of the wings 4 4. 'I'he surfaces 6 6 and 1 1 of the tip, which converge to define the curved knife-like edge 5, are smooth and connoidal. Transverse cross sections of the tip,

taken for example-on line 6 5 and 1 1 of Figure 4, are attened ovals, having their major axes lin a plane common to curved knife-like edge 5 and the needle shank wings 4 4. y

In Ause the needle is so mounted, in a pick-up or sound box mechanism, that one ofthe wings 4 leads, and the other trails, as the needle moves along a record groove in which itis operating. With the wings 4 4 thus located, the curved knife-like edge 5 of-the needle tip is disposed longitudinally of the record groove. In these circumstances it is the smooth connoidal surfaces 1 1 which engage the sides ofthe record groove with a minimum of 'destructive wear.

' oftentimes 'in the operation of a phonograph the needle, sustaining as lit does the weight of a pick-up orv sound box mechanism and its associated parts, is dropped upon the record with a shocking force which isenormous in relation to the permissible sizes of the needle and its tip.

which embraces the hard tip and occupies the surface scratches and fissures thereof, has become exceedingly hard, pursuantto the-Welding or fusing operation, as hereinbefore explained.

It will be found that after the needle has co- 5 operated with-a very great many records, the somewhat abrasive materials, which are included in present-day records, will have polished the leading arc of the curved knife-like edge 5 of the n eedle tip to a more or less straight edge. When this has been found to have occurred. the needle is reversed, with relation to the pick-up or sound box. In other words, that one of the wings 4 which formerly trailed is now caused to lead as the needle progresses along a record groove. In consequence of such reversal of the needle, the formerly trailing arc of the knife-like edge 5 now leads. It in time, and after the playing of a very great many records, also becomes polished to a more or less straight edge which intersects the other of said straight edges. Thereafter it is desirable to reverse the needle, each time the phonograph is serviced, to place one and then the other of such polished straight edges in sliding contact with the bottom o f the groove of the A record to which the needle is applied.

The needle of the present invention is practically immune from flexures at right angles to its path along a record groove, by virtue of the stiffening ribs 3 3 and that hardening of the shank, 30 in the region of hard tip 2, which resulted from the welding or fusing operation. Being thus immune from lateral ilexures it is adapted to respond to and faithfully reproduce the very high and very low sound frequencies which conven- '35 tional phonograph needlesrfail to detect, slur, or reproduce as sound of inadequate volume.

Byl swaging the needle shank to the cross section depicted in Figure "5, I realize a three-fold advantage, i. e., 1) facilitate very rapid air cool, 40

ing of the shank after the fusing or welding operation, (2) index the knife edge 5, and (3) stiifen against lateral iiexures that portion of the shank which extends betweenthe record being played and thev pick-up or sound box by which the needle is carried. That portion of the needle which is received by the pick-up or sound box is relatively soft, the more effectively to be engaged and held by the set screw or other needle-holding device with which the pick-up or sound box is 5 provided.

What I claim as new and desire to secure by Letters Patent of the United States is:

A phonograph needle comprising a berylliumcopper shank and a relatively harder tip set on and in one end of the shank, the end of the shank which embraces the tip being harder than the other end of the shank.

- ARTHUR J. OLSEN.

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