US393465A - Method of preparing phonograph recordtn - Google Patents

Description

(N-O Model.)

T. A. EDISON.

METHOD OF PREPARING PHONOGRAPH RECORDING. SURFACES.

No. 393,465. Paltented Nov. 27, 1888,

UNITED STATES THOMAS A.

PATENT OFFICE.

nnisonos LLEWELLYN PARK, NEW JERSEY, ASSIGNOR 'ro THE EDISON PHONO GRA PH'COMPANY. OF NEW JERSEY.

SPECIFICATION forming part of Letters Patent No. 393,465. dated November 27', 188 8.

Application filed July I, 1888.

'To all whom, it may concern:

specification.

In my phonograph I employ a removable phonogram-blauk having a recording-surface of a yielding material. 'I prefer to use a wax or a wax composition for the purpose, and I also prefer tomake the entire blauk of the'wax or waxcomposition. These blanks after he- 'ing mounted in the machine have their recording-surface turned true by a knife which is. carried by the rocking holding-arm and 'the point of which is preferablyiu close proximity to the recording-point. The blanks-used with" my machine are also preferably adapted to. have. their surfaces turned ofi by thissame cutting-tool for the purpose of using them a number of times, an old record being removed to make place for a newone. I have heretol'orc employed as the cutting-tool a knife with its cutting-edge parallel with the axis of the phonogram-eylinder and practically at right angles to the track of record. Ilhave discovered that wax and similar yielding materials, by reason of their elasticity and the cohesion of the particles, are not turned off smoothly by the tool, but that microscopic cracks or breaks in the surface are formed which are parallel with the .edge of thecutting-tool. To these cracks or breaksI attribute, in a measure, the production of foreign sounds by the record. These cracks or breaks are not as deep as the track made by the recording-point, but since the recording-point meets at the one time the resistance due to material of the full depth of its incision and at another time(when crossing a crack or break in the surfacela lc'sser body of material I have found that the record produced is correspondingly affected, having irregularities causing false vibrations in the reproducer. I have found that the effeet of these cracks or breaks is greatly modified and the trouble arising from them largely overcome by so cutting or turning 05' the surface of the blank that the cracks will beob- Serial I10. 279,393. (No model.)

cording-point. The improved effect, I think, is due to the fact that when the cracks are oblique the recording-point does not meet the crack across-the full width of its advancing -edge at one time, but only across a portion of such edge,andthedisturbauce is more grad:

ha] and is extendedovera greater time.

In the accompanying drawings, forming a part'hereof, Figure 1 is a vertical transversesection of a phonograph provided with a turning-oil tool; Fig. 2, aview showing the phonogram-blank being cut by the tool and illustrating the relative positions of the cuttingtool and the recording-point; and Figs. 3 and 4 are views onan exaggerated scale showing the relation between the recording-poi nt of the phonograph. and the cracks in the recordingsurface.

A is the revolving phonogram-cyl i ndcr', having the W3. phon gra-m blank B carried thereby.- v v G is the rocking holding-arm carrying the recorder D and thecutting-tool E. This toolis a knife mounted on the end of a lever, F,

pivoted to the arm 0. The end of the lever F'in rear of the pivot passes over'the head of an adjusting-screw, a, while a spring, 7), draws it downwa'rdly against said-screw. The point of-the knife E is oblique, as shown in Fig. 2, the cracks produced inthe wax recording-surface by it being oblique to the track of record made by the point a of the recorder.

In Figs. 3 and iris-shown in horizontal section the 'recording-point'c, while d represents the cracks in the recordingrsurface. If those cracks are parallel with the advancing edge of the recording-point, as shownin-Fig. 3, the 'recordingpoint will meet the cracks at the :same'time'across the full width of its advancing'edge, while if the cracks are oblique, as in Fig. 4, only aportioinof the advancing edge of the recordingpoint'will be in the crack at any one time, and the disturbing eficct of the crack will be distributed over a greater space of time, and hence will be more gradual.

It will be understood that the cutting-tool isto' be used either alternately with the recorder or simultaneously therewith. In the latter case the cutting'tool is placed somewhat in advance of the recording-pointin the direction of longitudinal mo ement of said point, as is illustrated in Z.

I do not claim in this application the recording-point and cutting-tool adapted to be operated simultaneously, this being claimed in my application filed May 29, ll88 8, Serial No. 275,441.

In my application No. 784, Serial No. 279,322, filed'July 7, 1888, I have claimed the phonograph provided with a turning-oil tool having a cutting-edge oblique to the track of record. This application relates to the method of preparing phonograph recording-surfaces by means of an oblique cutting-edge. It is obvious that the method might be carried into effect without mounting the cutting-tool upon the phonograph itself, since such tool might be employed in any suitable machine, such as 20 a lathe or any modification of a lathe.

What I claim is-- v 1. The method of preparing phonograph recording-surfaces, consisting in turning 011 such surfaces by a tool having a cutting-edge acting 25 obliquely to the track of record, substantially as set forth. I

2. The method of preparing phonograph rcco1 ding-surfaces of wax or a wax composition, consisting in turning off such surfaces by atool 30 having a cutting-edge acting obliquely to the track of record, substantially as set forth.

This specification signed and witnessed this 30th day of June, 1888.

THOS. A. EDISON. Witnesses.

WILLIAM PELZER, A. W. KIDDLE.

Images