US1399917A - Phonograph - Google Patents

Description

I I I NOV- 3; 1919. I

. 1,399,917, Patented Dec. 13, 1921.

EVELYN J. RUIPERT ATKINSON, OF MELBOURNE, V

BIA, AUSTRALIA.

PHONOGRAIPH.

Specification of Letters Patent.

Patented Dec. 13, 1921.

Application filed November 3, 1919. Serial No. 335,339.

T 0 all whom it may concern:

Be it known that I, EVELYN J. RUPERT ATKINSON, a subject of resident of Melbourne, in the State of Victoria, Australia,.have invented certain'new and useful Improvements in Phonographs,

of which the following is a specification.

The invention relates to phonographs, and particularly to phonographs adapted to reproduce sound from disk records.

An object of the invention is to produce a longer record on a given sized disk than is at present obtained.

Another object of the invention is to improve the tone of the reproduced sound by causing the undulations or waves corresponding to a given note to be of the same length at all parts of the record groove.

Another object of the invention is to provide a disk record in which the undulations corresponding to a given note are of the same length at all parts of the record groove. Disk phonograph records consist of a disk having a spiral or radially progressinggroove therein, in which the undulations representing the sound waves are formed. The undulations may be vertical and formed in the bottom of the groove or may be lateral and formed in the sides of the groove. Since the groove progresses radially, and occupies the larger portion of the area of the disk, the outer portion of the spiral groove is much longer than the inner portion of the spiral groove. When the disk is rotated at constant angular velocity, as is the usual procedure, the lineal velocity of the outer portion of the groove is much greater than the linealvelocity of the inner portion of the groove. For instance, in a ten-inch record, the diameter of the outer'circle of the spiral groove is about nine inches and its length about twenty-eight inches, whereas the diameter of the inner circle is about four inches and its length about twelve inches. Since the disk rotates at constant angular velocity, both in recording and reproducing, it follows that at the beginning of the record the groove moves at the rate of 28 inches per revolution, under the stylus, and at the end of'the record at the rate of 12 inches per revolution, under the stylus, so that the lineal speed of the groove with respect to the stylus is constantly varied during the recording or reproduction of the record. This causes the-undulations or waves'in the outer part of the groove to be much longer thin-necessary and conse- (arreat Britain, and a the disk, both irfrje at a constantly quently a much longer groove than necessary is required to reproduce a given selection. V hen the undulations are longer than necessary, a hissing soundi'sjproduced, as the stylus moves over the recdrd, thereby interferng with the tone of reproduction. n accordancewitlij'my invention, I rotate ""ding and reproduction, g angular velocity, so that the speed of the groove under the stylus is constant, thereby producing undulations (for a given note) of the same length or spacing at all parts of the groove.

The invention. possesses other advantageous features, some of which, with the fore going, will be set forth at length in the following description, where I shall outline in full, that form of my inventionwhich I have selected for'illustration in the drawings accompanying and forming part of the pt esent specification. In said drawings I have shown one specific embodiment of my invention, butit is to be understoodthat-I do not limit myself to such form, since the invention, as expressed in the claims, may be embodied in a plurality of forms. In the drawings I have shown the invention as applied to a sound reproducing apparatus, but it is to be understood that it may be applied in the same manner to a recording apparatus.

Referring to said drawings: ,5,

Figure 1 is a side elevation oii' 'a portion of a phonograph showing one form of my invention applied thereto.

Fig.2 is an underneath view of the record table, showing the driving mechanism.

Fig. 3 is a planner top v ew-of the record I ducing machine comprislng a rotating table or disk record support record 2 rests. Engaging of the record is a stylus sound box 6, which is supported on the angularly movable tone arm- 7, The needle enan undulation or wave' 4, upon which the j in the groove 3 5, secured to the gages in the groove and travels substantially radially across the face of the record as it' follows the progressionof the groove. The lower face 8 of the table 4 is smooth and arranged below said table and parallel, or substantially parallel, to the radius thereof, is a shaft 9 which is rotated at constant speed by any suitable phonograph motor.

The shaft is suitably supported in bearings secured to the base 12 arranged below the table. The shaft9 is approximately parallel longitudinally thereof, is a wheel or roller 16, having a friction surface, such as rubber, which is in frictional contact with the smooth under surface of the record table The undersurface of the table may be covered with a sheet of rubber, when desired, to increase the frictional contact, but a smooth, metallic surface may be employed to advantage. The table bears with slight pressure against the wheel 16, so that there is a minimum of slippage between the wheel and the disk.

Means are provided for moving the wheel 16 radially of the disk in time and coincident with the radial progression'of the stylus acting in the groove, so that the radial displacement of the Wheel and stylus are always the same. Preferably, the wheel lies directly under or substantially directly under v the stylus. Connected "to or secured to the tone arm 7, so that it moves angularly simultaneously and equally therewith, is an arm 17, concentric with the'center of rotation of the tone arm.- The arm 17 is provided at its outer end with a forked end 18 which embraces the wheel 16, causing it to move longitudinally on the shaft 9 coincidently with the radial movement of the stylus. As the wheel rotates at constant speed and moves radially in contact with the table in time with the radial movement of the stylus, the lineal speed of the groove under the stylus is constant at all parts'of the-groove. This produces a uniform action on the stylus at all parts of the groove, producing uniformity of tone and permits the recording of a longer selection on a given-sized disk record than was heretofore possible with disk records rotating at constantangular velocity.

I claim:

1. In a phonograph for reproducing from disk records, a rotatable support for the rec- 0rd, a rotatable shaft arranged parallel to the surface of said support and disposed radially with respect to said support, a

wheel engaging said surface and splined to said shaft, means for rotating said shaft, and means controlled by a record on said support for moving said wheel longitudinally of said shaft.

2; In a phonograph for reproducing from disk records, a rotatable support for the rocord,'a rotatable shaft arranged parallel to and below the surface of said support'and disposed radially with respect to'the axis of rotation of the support, a wheel slidably and nonrotatively' mounted on said shaft, means for rotating the shaft, and a lever secured to the tone arm of the phonograph to extend radially. therefrom and having a forked end embracing the sliding wheel so as to shiftthesame along its shaft under the control of the swinging movement of the tone arm. I

In testimony whereof I have hereunto set my hand at asadena, California, this 24th day of October, 1919.

I EVELYN J. RUPERT ATKINSON]

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