US1442299A - Sound record - Google Patents

Description

Patented Jan. 16, 1923.

UNITED STAT-Es PATENT OFFICE.

HENRY K. SANDELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO HERRT S.

CHICAGO, ILLINOIS. 4

MILLS, OF

SOUND RECORD.

.Application led February 26, 1921. Serial No. 447,927.

To all whom t may conce/1112,.'

Be it known that I, HENRY K. SANDELL, a citizen of the United States, residing at 221 South Green Street` Chicago, in the county of Cook and State of Illinois. have invented a new and useful Improvement in Sound Records` of which the following is a specification.

In accordance with the present invention a sound record. for example, of the disk type, is prepared having an auxiliary groove for thereturn of the tone arm from the end of the sound record groove or spiral to its beginning. A record provided with such a gioove is illustrated in the accompanying drawing, in which- Fig. l is a plan view of a record, and

Fig. 2 a partial sectional View thereof.

The numeral 5 indicates a disk record, of which the annular space 6 is provided with a spiral sound record groove and the circular space 7 surrounding the central opening 8 is provided with the label. Outside the space 6 is an annular space 9 having a plane surface, and between the annular space G and the central circular space 7y is an annular 'space l0 having a plane surface.

In addition to the spiral sound record groove occupying the space 6 a groove ll is formed in the record for returning the freely-movable tone arm from the end of the sound record groove to its beginning. This groove Y starts in the record groove spiral after the termination of the sound Waves, traverses the surface 10, the label surface 7, if necessary, and the spiral groove 6, entering the surface 9 with aV re-entrant curve which returns it to the initial portion of the groove portion 6. The pitch of the initial portion 11a of the groove l1 is slightly greater than that of the grooves of the groove portion 6 and increases, rapidly, preferably as a cycloid curve, and thereby causes the tone arm to travel rapidly out of the area- 6. The curvature of the groove 1l is preferably such as to carry the tone arm to the beginning of the record groove in less than one complete revolution of the record, and preferably in more than revof lution. The terminal portion 11b of the groove 11 is curved to merge into the spiral groove in area 6. The groove 11 is made of slightly greater depth than the sound record groove, its edges being clean cut in order that the passage of the sound reproducing stylus over the across groove l1 will'not result in a click' or other noise.

In playing the record With an instrument having a freely swinging tone arm, the needle is placed in the, spiral groove in the space 6, and is carried by that groove across the said space. When it reaches the initial portion 1la of groove ll it is carried by that groove across the record and across the space 6 provided with the record groove into the annular space 9, and is returned by the end portion 1lb of the groove to the beginning of .the sound record groove in space 6.'v

Altho the present invention has been described in connection with the specific details of an embodiment thereof, it is not intended that these details'shall be regarded as limitations upon the scope of the invenl. A sound record provided with a spiral sound record groove and an auxiliary groove, the latter groove beginning near the end of the sound record groove, cutting across the record Within the record groove and extending across the portion ofthe record oc cupied by the sound record groove, and termiinating near the beginning of the sound record groove.

2. A sound record provided with a spiral sound record groove and an auxiliary groove of slightly greater depth than the sound record groove, the latter groove beginning near the end of the sound record groove, 'cutting across the record Within the record groove and extending across the portion of the record occupied by the sound record groove, andterminating near the beginning of the sound record groove.

3. A sound record disk provided with a groove of slightly greater depth than the sound record groove, the latter groove beginning near the end ofthe sound record groove, Cutting across the record within the recoi-l groove and across the portion of the record containing the sound record groove and ter- 'minatng near the beginning of the sound record groove, the 'initial and terminal por' tions of the auxiliary groove merging into the sound record roove and the entire auxiliary groove having an angular magnitude on the record of less'than 360 and more than HENRY K. SANDELL..

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