US1250637A

US1250637A - Sound-reproducing machine.

Info

Publication number: US1250637A
Application number: US58698510A
Authority: US
Inventors: Percival James Packman
Original assignee: Aeolian Co
Current assignee: Aeolian Co
Priority date: 1910-10-14
Filing date: 1910-10-14
Publication date: 1917-12-18
Anticipated expiration: 1934-12-18

Description

) P. .l. PACKMAN.

SOUND REPRODUCING MACHINE- APPLICATION FILED ocT.14. 1910.

1,250,637. Patented Dec. 18,1917.

UNI ED STATES PATENT OFFICE.

PERCIVAL JAMES PACKMAN, F HIGHBURY, LONDON, ENGLAND, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE AEOLIAN COMPANY, OF MERIDEN, CONNECTICUT, A COR-PO- RATION or CONNECTICUT.

Specification of Letters Patent.

SOUND-REPRODUCING MACHINE.

Patented Dec. 18, 1917.

Application filed October 14, 1910. Serial No. 586,985.

To all whom it may concern:

Be it known that I, PERCIVAL J AMES PACK- MAN, a subject of the King of Great Britain and. Ireland, residingat 66 Hamilton road, Highbury, in the county of London, England, have invented certain new and useful Improvements Relating to Sound-Reproducing Machines, of which the following is a specification.

This inventlon relates to sound reproducing machines in which hill and dale cut records are employed and has for its object to increase the capacity of a record without substantially diminishing the volume of sound.

It has been usual to cut a recordof the hill and dale type with the groove in the form of a U in cross section wh1ch.has'neces-- sitated the use of a reproducing stylus terminating in a small ball.

Owing to. theU form of the groove, it is not possible to obtain a very long record on the usual size of blank, as the convolutions of the spiral cannot be brought very close together and be cut to the required depth to give a good volume of sound owing to the risk of the convolutions overlapping one another to some extent.

According to the invention I cut a hill and dale groove of substantially a V shape in section and I employ a very fine or needle pointed stylus for the reproduction by contact of its extremity with the bottom of the V shaped groove. It will be understood that contrary to what is the case with a record formed by a U-shaped cutting instrument,

there is a definite and distinct line of track, that is, the bottom of thegrooye cut by the point of the instrument, which always coincides with the true convolutions of the s iral or helix, and against which the point 0 the In the drawings, Figure 1 shows diagram-' matically on a much enlarged scale by way of example a cutter of sapphire or other suit able substance for cutting the V on the record. The angle between the cutting edges is acute, andthe cutting faces or edgesare ground so as to leave a sharp point; will actually yield a very narrow space? the bottom of the groove against which the extremity of the fine or needle pointed reproducing stylus may contact.

The stylus used in carrying out this invention has a hard, fine or needle point, and is preferably made. of the highest grade hardened tool steel.

Figs. 2 to 6 show modified forms of tools adapted to be employed for cutting the V- shaped groove in a record. The tools are drawn to a large scale for the sake of clearness.

Fig. shows a greatly enlarged plan view of a small portion of a track made according to this invention, showing the'distinct line of track produced by the cutting of the groove and a Fig. 8 shows a cross section of the same on the line AB of Fig. 7

Fig.9 shows diagrammatically to an enlarged scale a reproducing stylus in position with its fine or needle point in the bottom of the V shaped groove of a record.

The stem of the stylus is provided of ample thickness with its extremity only reduced to a fine point so that it may fundamentally bear on the line of track at the bottom of the groove formed by the use of a cutting tool such as illustrated in F igs. l to 6.

Byv uch means it is possibleto secure reproduction of a hill and dale V out record without involving any substantial diminution in the Volume of the sound, while, furthermore, it is possible to cut arelatively great number of threads or inch and thus to mcrease the capacity of the record while maintaining fullness and .purity of tone without echo. It will thus be understood that the grooves cut will have? a minute width and therefore also a minute depth, and that by reason of the recording tool actin as a cutter the walls of the groove will e sharply and cleanly cut and by reason of the cutter having a sharp point a smooth and continuous line will be cut at the bottom of the groove. 1

The stylus is conveniently mounted in a h d r so that its mo em nt due to the tical undulations of the line of track are directly communicated to the diaphragm in the usual manner. I

What I claim as my invention and desire 5 to secure by Letters Patent is In a sound-reproducing machine, the combination of a hill and dale record having a groove of V-shaped section with a definite line of track at the bottom; and a stylus having a needle point of narrower ll-shaped sec- 1c tion bearing fundamentally on said line of track.

In testimony whereof, I afiix my signa-' ture, in presence of two Witnesses. v

PERCIVAL J AMES PACKMAN. Witnesses:

A. BRowNE, L. SIMMONDS.