USRE11857E - Phonograph - Google Patents

Description

Reissued Sept. 25, I900.

No. ll,857.

T. A. EDISON.

P H 0 N 0 G B A P H.

(Application filed Aug 1 8, l 900.

"2 Sheets$heel l.

Eng. 2.

No. ||,s57. Reissued Sept. 25, I900.

T. A. EDISON. PHONDGRAPH.

(Application filed Aug. 18, 1900.)

2 Sheets-Sheet 2.

UNITED STATES P TENT IPHON'OGRAPH.

SPECIFICATION forming part of Reissued Letters l 'atent No. 11,857, dated September 25, 1900.

Original Hit-652,415 '7, dated-June 26, 1900. Application for reissue filed August 18, 1900. Serial No. 24,246. I

To all whom it may concern:

Be it known that I, THOMAS A. EDISON, a citizen of the-UnitedStates, residing at Llewellyn Park, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvementin Phonographs, (Case No. 1,014,) of which the following is a specification.

My invention relates to improvements in phonographs; and my object is to produce a phonograph wherein the loudness and-quality of the reproduction will be increased;

Experience has demonstrated the superiority of the type of recorder described in thy Patent No. 430,278, dated June 17, 1890, by

which will be obtained a record composed of a series of more or less connected gouges of varying dimensions, all of less depth than width and presenting in cross-section at any point an arc depending in extent upon the:-

depth of cut of the recorder. A record of this character oficrs a largebearing-surface length than width; By my present'improve-- for the customary spherical reproducing device and causes the latter to track automattions of the record representing fundamental tones and principal overtones, because some of the waves or gouges thereof are of less went I overcome this objection and obtain a reproducer for use in reproducing from records of the character described and which will automaticallytrack the record-groove and engage all portions thereof representing fundamental tones and principal overtones even vwhen the waves or depressions are greater in width than in length. In this way I am enabled to obtain better reproductions without the necessity of increasing the pcripheral speed of the recording-surface. Itis obvious that in the operation of the phonograph the formation of such representative waves or depressionshaving a greater width than length can be avoided by increasing the peripheral speed of the recording surface and that wh'enf the waves are thus: always characterized aspherical, reproducer can be effectively used; but the increase in speed i is objectionable, because the increased pressure imposed on the recording deviceprevents the latter from. responding as sensitively to the-soundwibrations as when a'lower speed is employed, and hence even the principal overtones will be in part at least omitted or imperfectly recorded. By means of my present improvement I eifect a perfect tracking of the record, not byv changing or distorting the record, but by the employment of a.re-'

producer of such aform that it will enter all portions of the record as at present made at the usual surface speeds and which are more nearly graphically representative of the original sounds than are records made at abnormally-high surface speeds.

To this end my invention consists in employing, in combination with a record-groove of the character described, a reproducer pre senting in cross-section to the record a curved form not greater than the curve of the cutting edge of-the recorder and preferably of a slightly-less radius than that curve and which presents longitudinally of the record a bearing-surface roundedto preventwear and of a materially-less radius than is presented to the record by the ordinary spherical reproducer. Preferably the specific form of reproducer which I employ is a cylinder inclined-to'the tangent-of a'cylindrical phonogram'or to the record-surface of a flat pho-- nogram, the bottom edge ofthe cylinder engaging the groove and said edge being provided with a rounded head or projecting rib, which engages the record.

In order that my invention may be better understood, attention is directed to thefaccompanying drawings, forming a part of this specification, and in which- Figure 1 is a sectional .view taken lengthwise of the record-groove, illustrating the manner of forming the record by means of a recorder of the type described-in my said patent, the parts being enlarged for the purpose of clearness; Fig. 2, a plan view, on an' enlarged scale, of ia record-groove produced by a recorder having a curved cutting edge;

Fig. 3, a. diagram showing in longitudinal section, on an enlarged scale, a portion of a record-groove, at a a spherical reproducer engaging with 'a record-wave of less length than width, and at b a spherical reproducer engaging with a record-waveof greater length than width; Fig. 4, a section longitudinally through the record, on an enlarged scale,- showing one form of the improved reproduce! enga-gingwith a record- Wave of less length 5 than width; Fig. 5, an enlarged section taken longitudinally of the record, showing the improved reproducing device placed in the opposite direction from that shown in Fig. 4 and illustrating indotted lines (the usual 1o sphericalreproducingdevice, wherebya comparison'of the two reproducers can be conveniently made; Fig. 6, a section on the line 6 6 of Fig. 5; Fig. 7, a side elevation of the preferred form of the improvedrcproducer, and Fig. 8 a section on the line-1O 10 of Fig. 7.

In all of the above views corresponding parts are represented by the same numerals and letters of reference.

1 represents a phonogram-blank, which is preferably cylindrical in form, of a soap-like com position, as is now common. Flat phonograms may be employed and other materials may be,used.

2 represents the recorder of the type described in my said Patent No. 430,278, said frecorder having a curved cutting edge 3 and being preferably hollowed out to facilitate the gouging or cutting of the records. With such a device the record will partake generally of the appearance shown in Fig. 2, being composed of a series of more or less connected gouges of varying dimensiOns,according to the amplitude or extent of movement of ,therecording diaphragm and to t-he rapidity of vibration thereof. Owing to the relatively-great diameter of Ihe'recording edge to the depth of cut all the depressions of which the-record is formed are characterized bya greater width 40 than depth. Some of these waves-as, for instance, 4 4 are greater in length than width; but others, such as 5.5,are found in practice to be of less length than width. The eifect of an attempt to reproduceth ese records with a spherical repro'd ucer is shown clearly in Fig. 3, wherein two spherical reprod ucing-balls 6 6 are illustrated. -.In the case of the waves which are of greater length than .width the reproducer, as at b, will be free to engage the entire length of the wave; but when the length of the wave is less than its width the spherical reproducer, as shown at a, will not be al- .lowed to enter the record-groove, but will be arrested by the crests of the adjacent waves'. The reproducer in the latter case, therefore, doesnot accurately-track the record and the reproducer-diaphragm is not vibrated in accordance'with the record.

Referring to Fig. 4, 7 represents one form of the improved reprod ucer,which may be con- .nected directly to the diaphragm or to lever 8, which is connectedtothe diaphragm 9 by a link 10. The reproducer is preferably cylindrical in form, with its lower edge resting in the groove, the axis of the cylinder being preferably inclined at an angle of about fortyfive degrees from the tangent of a cylindrical track accurately in the groove.

record or from thefaceof a flat record; v 'hhe ord, as shown in Fig. 5. The curve of theengaging edge of the reproducer, as shown in Fig. 6, is not more than the curve of the cutting edge .3 of the recording device and it is preferably slightly less than that curve, so that the reproducer can always be free to The curve presented by the engaging edge of the reprodncer longitudinally of the wave, as shown in Figf 5, is very much less than is presented by spherical reprmlucer, as may be seen from an examination of thisfigure. Hence a depression or wave which could not possibly be engaged by a spherical reproduce! can be accuralely tracked by my improved reproducer. At the same time the bearing-surface of the reproducing device is almost as great as that which is presented by a spherical reproducer, so that there will not be any excessive wear. By employing a reproducing device of this'general character which will present lengthwise to the wave a very much less surface than is the case with the spherical reproducer I am enabled to accurately track a record even when certain of the waves, or

all of them, representative of fundamental tones and principal overtones, are materially less in length than in width, and I therefore do away with the necessity of preventing the occurrence of such waves by operating the phonogram at an abnormally-high speed. It will be understood that instead of using a re producer which is cylindrical in form any other form of reproducer may be employed presenting a curved surface to the record and with its longitudinal dimensions contracted suflicien tly to allow it to enter to the full depth.

in the record-groove, even when the waves are veryishort and deep. Y

The preferred form of. the reproducer is shownin Figs. 7 and 8, wherein the reproducer consists generally of a cylindrical shank having a rim 11 atiits bot-tom edge, the curve presented by such rim atright angles to-the record being shown in Fig. 8, while the curve which is presented by such rim longi tudinally of the record is shown in Fig. '7. It is evident that this form of reproducer can be placed at a less inclination to the record than the form shown in Figs. 4 and 5, and I prefer to support it at no greater inclination to the record than is necessary to enable its holder to clear the record surface; In' all forms of the rep'roducer which have been illustrated thebearing-surface has a radius which is very much smaller longitudinally of the record than crosswise thereof, and this bearing-surface is one having the same width throughout its length, the length'of the bearing-surface being at right angles to the length of the record-groove. The width of the bearing-surface may be reduced to the minimum when the recording-surface is made of a ma- I terial which is sufficiently hard to withstand the scraping action of such a bearing-surface; but with softer recording materials, the width of the bearing-surface of my improved reproducer should be increased to produce the requisite life of the record. I have found, however, that with recording-surfaces made of the soap-com positions now commonly used for the cylinders of the phonograph the proportions of width to length shown in the drawings can be employed without excessive wear of the record.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is as follows: I

1. In a phonograph, the combination with -a phonogram having a record thereon formed of a series of more or less connected gouges or waves with rounded sides and bottom, some of said waves representative of fundamental tones and principal overtones being characterized by a greater width than length, of a reproducing device having-a curved bearing-surface engaging .the bottom and side walls of the record and of a form adapted to enter and accurately track all of such representative waves, substantially as and for the purposes set forth.

2. In a phonograph, the combination with a phonogram having a record thereon formed of a series of more or less connected gouges or waves with rounded sides and bottom, some of said waves representative of fundamental tones and principal overtones being characterized by a greater width than length, of a reproducing device having'a curved bearing-surface which engages the record-groove and reduced in its longitudinal dimension, whereby the reproducing-surface may accurately track a wave-having a'less length than width, substantially as set forth.

3. In a phonograph, the combination with a phonogram having a record thereon formed of a series of more or less connected gouges or waves with rou nded sides and bottom, some of the waves representative of fundamental tones and principal overtones being characs I terized by a- .greater width than-length and said waves differing from each other in the slope of their descending and ascending walls,

of a reproducing device having a curved bearin g-surface engaging the sides and bottom of the record and of a form adapted to enter-and accurately track all. of such representative waves, substantially as and for the purposes set forth.

4. Ina phonograph, the combination with -'a phonogram having a record thereon formed of a series of more or less connected gouges or waves with rounded sides and bottom, some of the waves representative of fundamental tones and principal overtones being characterized by a greater width than length, of a reproducing device having a curved bearingsurface engaging the sides and bottom of the record to accurately track all of such representative waves, said reproducing device being of such a form as not to engage simultaneously the descending and ascending slopes of the waves, substantially as set forth.

5. In. a phonograph, the combination with a phonogram having a record thereon formed ofa series of more or less connected gouges or waves with rounded sides and bottom, some I of said waves being characterized by agreater width than length,- of acylindrical reproducing device placed at an angleto the record and with its lower edge engaging the sides and bottom of the record, substantially as set' forth. 6. In a phonograph, the combination with a phonogram having a record thereon formed of aseries of more or less connected gouges or waves with rounded sides and bottom, some of said waves being characterized by a greater width than length, of acylindrical reproducing device having a rounded bottom edge which engages the sides and bottom of the record, substantially as set forth.

7. As a new article of manufacture, an improved reproducer for phonographs, havinga curved engaging edge, said edge being curved longitudinally of the record in a smaller radius than at right angles thereto, substantially as set forth.

8. As a new article of manufacture, a cylindrical reproducer maintained in an inclined position and having its bottom edge rounded for engagement with the record, substantially as set forth.

9. An improved phonograph-reproducer, consisting of a cylinder having at one end a rounded bead or'rib, projecting beyond the periphery of the cylinder, which rib forms the bearing-surface of the reproducer, substantially as set forth.

Thisspecification signed and witnessed this 10th day of August, 1900.

THOMAS A. EDISON. Witnesses:

J. F. RANDOLPH, J. A. BOEHMS.

Images