US2310545A - Sound record carrier - Google Patents

Description

Feb.9,1943. F B 2,310,545

SOUND RECORD CARRIER Filed Sept. 19, 1939 lu A I NVENTOR.

I 7/ /21? Z'eber 1 f ATTORNEY hea dress, 1943 SOUND RECORD CARRIER Frank Rieber, Los Angeles, Calif., assignor to I Memovox, Incorporated, Cleveland, Ohio, a cor- Mration of Ohio Application September 19, 1939, Serial No. 295,812

This invention relates .to sound records, and especially to the blanks upon which such records may be carried, and particularly upon which the records may be formed by an embossing process.

It has been common in the past to employ a recording stylus mechanically cutting a groove on a blank in the form of a disk, the stylus point being vibrated in accordance with the impulses or sounds .to be recorded. While the record blanks in the past have beenquite satisfactory for use in connection with cutting styli, they are not suitable for use with embossing styli. It is one of the objects of this invention .to adapt the embossing process to records of this character,

and to-obtain embossed records of high quality.

It is another object of this invention to improve in general the quality and fidelity of such sound records.

It is another object of this invention to make it possible eiiectivelyto'utilize a very thin, flexible record, whereby little space is required for storage; and the danger of accidental breaking is obviated. i

It is still another object of this invention to provide a record blank made from a material such that :renders it possible to record with fidelity, the frequencies encountered in the higher register of audibility and particularly by an embossing-process.

This invention possesses many other advantages and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the drawing accompanying and forming part of the present specification. These forms-will now be described in detail, illustrating the general principles oi the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope'of the invention is best defined by the appended claims.

Referring to the drawing:

Figure 1 is a pictorial view of a sound record carrier embodying the invention: Fig. 2 is a fra mentary sectional view, illus- .trating the manner in which the sound record carrier may be supported upon a phonograph turntable.

Fig.3 is a pictorial view of'the clampingelement illustrated in Fig. 2;

The sound record carrier, which is in the form of a .thin disk, is preferably made from an appropriate plastic compound. The disk is made sumciently thin as to be very readily flexible. For

example,'there have been successfully used disks oi the thickness of .006 inchfor a disk having a diameter of eight inches. For larger disks, thicker materials may be used, such as .010 inch for diskshaving a diameter oi fourteen inches; and from .013 to .015 inch for disks-having a diameter of sixteen inches.

In most of these instances, both sides of the disk may be utilized for recording purposes.

By making definite provisions, it is possible accurately to record sound waves in the higher register in an efiective manner. One of the factors for this is the material chosen for the disk i. This material is preferably an ethyl cellulose. It has the property of yielding abruptly beyond a definite pressure level, so that the embossing process of recording may. readily be used. 1

It is also free irom granular impurities. which impurities may cause irregular recording and reproducing eflects. Furthermore, the record carrying surface of the disk i is treated with: a very thin film of lubricant such as carnauba wax, or any other lubricant capable of adhering very closely to the disk surface. Such lubricant may be applied, as by first dissolving the lubricant in a solvent, andby spraying it or otherwise spreading it on the disk surface. It may then be polished.

Fig. 4 is a fragmentary sectional view, showing a modified form of the invention: and

Fig. 5 is a fragmentary top plan view of the modification illustrated in.- Fi 4.

The extremely smooth record surface thus.

obtained; in conjunction with an extremely smooth Jewel recording stylus, such as a sapphire, makes-it possible to apply the recording stylus at a steeper angle to the surface of the disk, without danger of irregular recording ac-' tion. Therefore, since the disk area contacted by .the stylus is less than if the angle were not so steep. the stylus can more effectively impress or must be placed upon a smooth flat surface, so].

or beginning to contact theouter edge of the disk I.

as to ensure that-the embossing forces will be fully effective upon the disk. For this purpose the rotating phonograph table 2, shown as mounted on a spindle 3, has a smooth upper surface 4. Upon this upper surface the disk I is placed. In the usual thick disk records it has been common to drive the disk by the aid of friction between the disk and the table. In the present instance this, of course, is impossible because of the necessity of providing a smooth supporting surface. means for driving it is provided for.

For example, it is possible to clamp the outer edge of the disk I to the table, as by a resilient rubber rim 5. This rubber rim 5, acting as a resilient band, has an overlying'flange 6 adapted It also tightly embraces the vertical edge of the table 2, and may if desired be provided with an inwardly directed bead 1, projecting underneath the vertical edge of the table 2. Of course. there are other ways in which this drive can be eflected.

'For example, in the form illustrated in Figs. 4

and 5, the disk 8 is shown as having a central aperture 9 with a key-hole slot I0, through which a driving key II carried by the spindle I2 may be accommodated.

The recording is preferably accomplished at a constant linear rate, approximating six inches Therefore some positive.

record on. but one side of the record disk is .008

inch thick, then the recording groove is preferably .003 inch thick, the ungrooved portion being the same. With a double faced disk record having an over-all thickness oi .013 inch, the depth of the record groove on each side may be of the order of .004 inch, leaving an ungrooved central portion of about the same depth.

What is claimed is:

1. A thin flat, phonographic record, a rotary table having a smooth surface upon which said record rests, and means preventing relative angular movement between the table and the record, comprising a resilient rim member embracing the outer edge of the record and of the table. 4

2. A thin flat, phonographic record in the form of a disk, and adapted to carry a record groove progressing toward the outer edge of the disk, a rotary table upon which said disk is supported, and means coupling said table and disk in such manner as to obviate relative angular movement between them, while permitting said disk to be flattened over the table surface in response to a force acting outwardly, radially from the center, comprising a resilient rim member overlapping the edges of the table and the disk.

FRANK RIEBER.

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