US626709A - Process of making graphophone-blanks - Google Patents

Description

UNITED STATES PATENT OFFICE.

THOMAS II. MACDONALD, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE AMERICAN GRAPIIOPIIONE COMPANY, OF VEST VIRGINIA.

PROCESS OF MAKING GRAPHOPHONE-BLANKS.

SPECIFICATION forming part of LettersPatent No. 626,709, dated June 13, 1899.

Application filed August 23, 1898. Serial No. 689,351. (No Specimens.)

To all whom, it may concern:

Be it known that I,THOMAS H. MAoDoNALD, of Bridgeport, Connecticut, have invented a new and useful Improvement in Graphophone-Tablets and Processes of Manufacturing the Same, which improvement is fully set forth in the following specification.

My invention relates to the art of manufacturing blanks or tablets upon which soundrecords may be out or engraved, and more particularly to the process of treating the composition of matter of which the tablet is composed to the end that the same may be perfectly amorphous, free from all fibrous or other organic impurities, and without tendency to crystallization.

In forming a sound-record the method described in United States Patent No. 341,214 is now commonly employed, which method consists in cutting or engraving an undulatory groove in the surface of a suitable tablet by means of a cutting-style attached to a vibratory diaphragm upon which the sounds to be recorded are allowed to impinge. The force of the sound-waves is very weak, and it is essential to the accomplishment of the best results that the surface of the tablet should be such as to enable the style to cut a smooth undulatory line whose undulations shall correspond exactly to those of the recorded sound-waves. If there is any crystalline formation or any tendency thereto in the surface of the material composing the tablet, the shaving removed by the style is liable to follow the line of cleavage of the crystal, thus ofiering variable resistance to the action of the style and producing a groove whose irregularities do not correspond exactly to the undulations of the recorded sound-waves. It is also very important that the composition of matter composing the tablet should be free from all fibrous or other organic matter, as such otters uneven resistance to the cutting action of the style, causing it to form a rough and inaccurate record. In some cases the style rides over the fiber and makes no record at all, causing what is known as blind spots. In other cases the style fails to cut the fiber, but pulls it out bodily, leaving a hole or depression where there should have been a smooth out. Again, the style, instead of cutting the fiber or removing it bodily, tears through it, leaving rough jagged ends which when the rubbing style of a reproducer rubs over them give a rough harsh quality to the reproduced sound. Moreover, the organic matter is liable to ferment and mildew, greatly lessening the value of the blank and destroying the record out therein. In my Patent No. 606,725, dated July 5, 1898, I have described and claimed a process for making blapk tablets whereby a superior tablet may be produced which is to a large extent lacking in the objectionable features above described and upon which records of a high order of merit may be produced. I have found, however, that there is often a tendency to form crystals upon the surface of blanks made by such process, which tendency is due to the presence in the blank of the water of crystallization. I have also learned that such tablets sometimes contain fibrous or other organic impurities, such as fine dust particles, which are at all times floating in the air and which the most vigilant care could not entirely exclude.

The object of the present invention is to produce a blank tablet which shall be without any tendency to crystallization and in which all fibrous matter shall be destroyed; and to this end the invention consists in subjecting the composition of matter which is to constitute the tablet to a degree of heat suflicient to entirely drive 01f all water of crystallization and entirely destroy all fibrous and other organic impurities in the composition of matter.

Heretofore in the treatment of the composition of matter of which the tablets were to be formed heat has been resorted to for the purpose of eliminating the water; but great care has been taken not to exceed a temperature of about 330 Fahrenheit for fear of charring the composition and thereby rendering it unfit for use as a tablet material. This tem perature was not sufiicient to entirely eliminate the water of crystallization and would not destroy fibrous and other organicmatter. I have discovered, however, that the composition of matter may be advantageously subjected to a heat of from 450 to 475 Fahrenheit, and that by so doing the water of crystallization may be entirely eliminated and the fibrous and other organic impurities eliminated or disintegrated.

For the purpose of illustrating my invention and the best method known to me for putting the same into practice I will describe one composition of matter and the process of forming and treating the same preparatory to molding it into tablet form.

Formula: Stearic acid, free from oleic acid and glycerin, four hundred and eight pounds; alu minic hydrate, seven pounds; caustic=soda lye, eighty-five pounds. To this is added for the purpose of tempering paraffin, ozocerite, or similar material, seventy-two pounds. The caustic soda is incorporated in water until a lye of 37.5 Baum is obtained, and this is heated to its boiling-point, about 242 Fahrenheit. The aluminic hydrate is added and is quickly taken up by the lye. The stearic acid is melted and raised to about the same temperature, and the compound'of lye and aluminium slowly added thereto. It will unite readily therewith. It is preferred to employ about the temperature indicated, as thereby the formation of the composition proceeds gradually and without violent ebullition. The temperature of the molten mass is then raised to a point somewhere between 450 and 475 Fahrenheit. When the desired temperature has been reached, I allow the same to fall about 100 and then pour the mass into the molds in the usual manner. The fall of the temperature may be conveniently secured by putting out the fire and allowing the mass to stand a few moments.

It is not, of course, essential that all the ingredients constituting the compound material should first be incorporated in the mixture before heating the same to the high temperature required to drive off the water of crystallization and destroy all organic matter, as the ingredients may, if it is found advantageous, be heated separately to the high degree necessary, or partial combinations may be formed, these heated toa high degree, and then the partial combinations united to form the finished compound. I prefer, however,

to first incorporate and thoroughly unite all I claim as new, and desire to secure by Letters Patent, is'- 1. In the process of making a sound-record ing material, the improvement consisting in partially saponifying stearic acid, and then heating the mass to a temperature of about 460 Fahrenheit, substantially as described.

2. In the process of making a sound-recording material, the improvement consisting in mixing stearic acid with caustic-soda lye, and then heating the mass to about 460 Fahrenheit.

3. The improvement in the process of making sound-recording material which consists in heating such material to about 460 Fahrenheit, then cooling the same down to about 360 Fahrenheit, and then molding the material into the desired shape, substantially as described.

4. The process of making a sound-recording material consisting in dissolving aluminium in soda-lye, adding the solution to stearic acid, and raising the temperature of the mass to about 460 Fahrenheit, substantially as described.

5. The process of making a sound-recording material, said process consisting in addin g to stearic acid soda-lye with which a metal has been united, the lye being in such quantity as to'produce partial saponification, and heating the mixture to about t60 Fahrenheit, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

THOMAS H. MACDONALD.

Witnesses:

HENRY A. I-IUBBELL, E. W. SULHIE.