US1398529A

US1398529A - Phonograph-needle

Info

Publication number: US1398529A
Application number: US286534A
Authority: US
Inventors: Merton T Straight
Original assignee: Individual
Current assignee: Individual
Priority date: 1919-03-31
Filing date: 1919-03-31
Publication date: 1921-11-29
Anticipated expiration: 1938-11-29

Description

M. L STRAIGHT.

PHONOGRAPH NEEDLE.

APPLICATION FILED M'AR. 3|, 1919.

1,8 98,529. Patented. Nov. 29, 1921'.

- UNITED STATES MERTON STRAIGHT, OF ABEL, IOWA.

PHONOGRAPH-NEEDLE.

Specification of Letters Patent.

Patented Nov. 29, 1921.

Application filed March 81, 15 19. SeriaI Ho. 286,534.

To all whom it may concern:

Be it known that I, MERTON T. STRAIGHT,

' a citizen of the United States, residing at ones.

Adel, in the county of Dallas, State of Iowa, have invented .a Phonograph-Needle, of which the followin is the specification.

My invention re ates to styli for gramophones and particularly to those styli whlch are adapted to be used in, talking machines to reproduce sound from commerclal sound record tablets. When a steel stylus is bemg used to reproduce sound from a sound rec'- ord tablet, the tip or pointof the stylus always wears to a perceptible extent and a sharp edge is formed thereon wh1ch tends to cut and unduly wear away the walls of the grooves of the tablets and to produce a scratching sound. This wearing away of the stylus point has a tendency to embed small particles of steel in the walls of the.

grooves and thereby increase the scratching noises and these embeddedparticles in turn tend to increase the wear on the points of the styli. On account of the excessive wear of the stylus point and the wear on the sides of the grooves of the sound reproducing tablet, it is customary to use the steel stylus but once and when it has so been'used,'throw it away and replace it with a new one. The necessity of having to change the stylus every time a record tablet is played, is annoying to say nothing of the liability of getting the used styli mixed with the unused Styli'formed of a material softer than steel, such as tungsten, 'do not wear the sides of the sound grooves as much as steel styli do, but have a tendency to wear blunt and'thereby fillthe small angular notches in the grooves with the material worn from the styli. On account of the small notches being partly filled and the blunt portions of the styli having a tendency to ride over the smaller notches, some of the details of the tones'are sacrificed.

Therefore the object of my invention is to obviate the necessity of changing styli for each reproduction of sound from a record tablet and'to produce a stylus of cheap ma- .terial and one that is comparativel inexpensive to manufacture WhlCh may, e used to reproduce sound from a large number of tablets without substantlal 1n ury to the tablets and also toeliminate the scratching noise without sacrifice to the quality of tone.

A further object is to provide in connection with a stylus formed of natural clays or shales, new and improved means for clamping the stylus in the sound head of the sound producing machine.

Referring to the accompanying drawings:

Figure 1 shows a side elevation of the sound reproducing record and the sound head with one of my improved styli in position.

Fig. 2 shows a side elevation of the stylus.

Fig. 3 is a detailed end view of the stylus supporting member showing the stylus in section.

Fig. 4 shows a perspective view ofmy improved stylus supporting clamp.

Fig. 5 shows the top elevation of one of the trays in which the styli areplaced while being burned. r

' Fig. 6 shows a sectional perspective 'view of the trays in position relative to each other and taken on the line 6-6 of Fig. 5.

I have discovered that certain kinds of natural shale and clay possess the proper ingredients to make excellent styli for sound reproducing machines, capable of transmitting sound waves to the diaphragm in such a manner as to produce a mellow tone of fine quality and at the same time have a very hard and smooth surface which does not wear when engaging the grooves of a sound reproducing record.

In producing the styli, I first select material possessing the proper ingredients, preferably a red shale. This shale has a very fine grain and no rough particles and a large amount of aluminates and oxid of iron. In its natural state it possesses the property of being easily cutto'any desired shape and doesnot have to be ground or mixed before being burned or vitrified.

In making my styli I preferably cut the natural shale insquare bars which are dried at normal temperatures to harden and the bars of shale are dried they are placed in a special machine and cut to a cylindrical form having a taperin point at one end illustrated in Fig. 2 o the drawings and designated by the numeral 10. Sometimes it may be desirable to polish the point before being burned. This may be done by a special bufling wheel. The nature of the shale 5 from which the stylus is made somewhat determines this part of the process. The styli are now ready to be burned. To accomplish this without overheating and burningthe fine points and to prevent bending and warping them, I have provided a tray 11 having a top tray member 12 clearly illustrated in Figs. 5 and 6 of the drawings. The trays may be made of porcelain or any 7 suitable fire proof material. The tray 11 has in its upper surface a series of grooves 13 substantially the size and shape of a stylus and of a depth equal to one-half of the diameter of the stylus. A flange 14 .is provided on the outer edge of the upper face of the tray 11 and is designed to form a retaining rib. The top tray 12 has its under side portion provided with grooves 15 similar to those in the tray 12 and so spaced as to aline with the grooves 13, of the tray 11. When in position thereon, the tray 12 is held in position by the ribs 14 so that the grooves 15 will properly align with the grooves 13. When each of the grooves 13 has been filled with unburned styli, I place the top tray 12 in position and place the said trays in a suitable furnace or kiln. Heat is then applied and the temperature is gradually raised to a point where the styli will vitrify, after which the temperature is gradually lowered to normal. The styli are then removed from the trays and are ready for use.

I have found that styli so produced have the hardness about equal to that of a sapphire and have a very close-grained, smooth and polished surface.

I have found, however, that styli so made are somewhat brittle and have a tendency to breakwhen clamped in position in the sound head. This is due to the fact that the pressure applied by the set screw is unequally distributed over the surface of the stylus. To overcome this difliculty I have provided a pressure plate 16.

Fig. 1 shows a. gramophone body 17 hav ing a record 18, a sound head 19, the said head being provided with a stylus supporting member 20, all of which are of the ordinary construction and form no part of this invention.

The stylus supporting members are generally provided with a triangular shaped opening 21. The pressure plate 16 is designed to be made of soft steel or similar material and is of such a size as to loosely fit the large part of the opening 21 and has two parallel faces 22 and 23, and two inwardly inclined faces 25. One of the parallel faces is provided with a longitudinal cirs b cular groove 26, and is of a length equal to or longer than the opening 21. When it is desired to place a stylus in the opening 21 of the sound head, the cylindrical portion of the stylus 10 is placed in the opening 21, and adjacent to the angle opposlte the set screw 24. The plate 16 isthen slid in the opening with the face 22 adjacent to the side having the set screw, with the groove 26 adjacent to the stylus. If the set screw 24 is now turned, it will be seen that the stylus will be firmly gripped and the pressure evenly distributed, without breaking the stylus.

I have thus produced a stylus adapted to be used in connection with a gramophone or other sound reproducing mechanism that does not have to be changed when a new record is placed and can be used a very large number of times without injury to the sound reproducing record and at the same time eliminates the excessive noises without sacrificing the quality and clearness of the tone.

I am aware that heretofore a large variety of materials have been employed in the manufacture of styli for sound reproducing machines-and that numerous patents have been granted .for the discovery of these various substances or materials as designed for use in sound reproducing machines. At the present time, however, only two general classes of these materials have remained in general commercial use, and these two are steel and jewels.

The objections to the use of steel for this purpose have been heretofore set forth.

The objection to the use of jewels for this purpose is, primarily, in regard to their practically prohibitive expense.

The merit of'my invention or discovery. resides primarily in providing a stylus by which the same, or better, results, acoustically speaking, may be obtained as are obtained by the use of jewels, and at the same time provide such stylus at a cost which is merely nominal as compared with the cost of jewels, thus resulting in a great sav1ng of expense to the users of sound reproducing machines and at the same time gaining all of the advantageous results, both acoustically and mechanically speaking, as are attained by the use of jewels, and avoiding the difiiculties and disadvantages, both acoustic and mechanical, that are inherent in the cheaper materials that have heretofore been used for this purpose, such asthe necessity of frequently changing the styli, the injury to the records by the deposit of particles worn from the styli, and the defective acoustic properties thereof.

Another marked advantage of my invention is that necessary shaping and polishing may be done upon the natural shale before it is vitrified, and this obviously can be done much more rapidly, efliciently and economically than could be done after vitrification.

Furthermore in this connection, where the shaping of the stylus is done before it is hardened, then during the process of vitrification the exterior of the stylus becomes smooth, hard and tough, and far better for the purposes intended than if the shaping and polishing were done after hardening or vitrification.

I claim:

1. A stylus for sound reproducing ma- 10- chines, formed of natural shale artificially vitrified. 2. A stylus point machine's, formed of natural shale polished and artificially vitrified.

MERTON T. STRAIGHT.

for sound reproducing I