US2259715A - Sound record - Google Patents

Description

Oct. 21, 1941. w. L. WOOLF SOUND RECORD 7 File d Sept. 6, 1940 BY M444 1 4. M OOLF ATTORNEY$ I Patented Oct. 21', 1941 UNITED STATES PATENT OFFICE azsaus t sown RECORD I William- L. Woolf, Bayside, N. r. Application September 6, 19,Berlal No. 355,581 laim. (01. 214-43) This invention relates to a sound record and more particularly to one made of thin material. and requiring support for its sound recording surface during recording or reproducing operations.

Among the obiects of the invention may be mentioned the following: to provide a sound record which is made of durable material; a

sound record capable of playing a comparatively long period of time and one which may readily be shipped and easily be stored and particularly adapted for dictating machines wherein sound letters are mailed and filed.

The sound record of the present invention consists of a hollow truncated cone of flexible material, preferably cellulose acetate, such as that used in moving picture films. The details of construction and manner of use will be better understood in connection with the accompanying drawing, in which: I

Figure 1 is an elevational view of a sound record, its supporting drum and pressure rollers;

Figure 2 is an end elevation;

Figure 3 is a top plan view of that form of the invention in which the sound record is of such size and shape as to fit its supporting drum:

7 Figure 4 is a view similar to Figure 3 but showing the pressure rollers in disengaged position; and

material which adds to the mass and therefore is readily broken and is not easily shipped. Its

' mass is also too great to permit quick starting and stopping and therefore it is not suitable as a record for dictating purposes.

Sound records made on a motion picture film of cellulose acetate possesses many advantages,

among them being that of uniformity of speed.

.est expanded condition or in other words when both ends of the truncated cone are circles, isof much larger diameter at either end than the mandrel 4. In the form shown in Figures 3 and 4 the film 2 fits the mandrel t. The mandrel Figure 5 is a section on the line 5-5 of Figure 4.

The type of record heretofore generally employed for dictation purposes consists of a waxcylinder.

The wax cylinder has the advantage of uniform speed both in recording and reproduction at every point on the record. It has the disadvantage, however, of being unsuited to repeated playings due to its lack of durability. Further disadvantages are due to its relatively high mass. When used for dictating purposes, its diameter must remain small in order that the mass be contained within those limits required in quick starting or stopping. The wax cylinder, furthermore, is not well suited for storage or shipping and is not suitable for mailing.

having the same slope as the film and mandrel, I

are provided in order that the film may be held against the surface of the mandrel.

These pressure rollers 8 are carried by arms H which project from bushings It forming part of the upstanding arms '9 as shown in Figure 2. The shafts it are carried by the arms H, each shaft being parallel to the axis of its associate pressure roller 8. The shafts 22 form part of a frame i t which frame may be rocked about the shaft 82 as a pivot to permit the pressure rollers A disc record cannot well be employed for dictation purposes since it has the disadvantage of constantly changing speed with a resultant constantly changing frequency characteristic. The high frequencies are best on the outside grooves and become continuously poorer as the diameter of the groove decreases. Another disadvantage of the flat disc is the fact that it must be supported throughout its area and this is usually to be moved away from and toward the surface of the film. A spring it, one for each pressure roller tends to hold the pressure rollers against the film as shown in Figure 2. By rocking each frame about its axis 92 by means of fing'ers l8, Figures 2 and 3, each pressure roller may be moved away from the film to enable the latter to be placed upon the mandrel. A pin 20, Figure 1, provides means for attaching one end of the springs 86, the pin 20 extending through done by providing a turntable of metal or other each arm I I as shown in Figure 1. This serves as a stop for the projecting portion 22 forming part 01 the frame. The springs I! are so attached that the frame is held with the rollers I in contact with the film or in disengaged position.

In Figures 1, 2 and 3, the pressure rollers are shown in engagement with the film while in Flaure 4 these rollers are shown in disengaged position. n

The cone shaped film is slipped on over the mandrel and held in position by a disc 24 suitably 4 secured by a thumb nut 26.

A sound head is conventionally shown in F18- ures 1 and 2 and this head may be either a recording head or a reproducing head. A screw it may be provided for feeding the head transversely of the film surface. The him in the form of the frustrum of a cone as previously stated, is preferably formed of cellulose acetate. The sound record may be formed directly on the film by means of a recording head and stylus such as is shown in the patent to Madaler and Woolf No. 2,173,051, September 12, 1939. A sound record made of this material and in the form shown provides a medium which may readily be stored and .when properly protected may be folded and mailed.

A record four inches in perpendicular distance between its bases and having the larger base 5%" in diameter and the smaller base 4%" in diameter will permit twenty-five minutes of continuous dictation in which the speed averages twenty feet per minute. At such speed dictation of quality far superior to that produced by the conventional commercial dictating machines may be had. At twice this speed or forty feet per minute. the cone of the dimensions above stated will support twelve and a half minutes of recording of excellent quality. At such speed enjoyable music is recorded and reproduced.

A record of the form and material described is well adapted for dictating purposes. when the mandrel is of thin aluminum it permits extremely quick starting and stopping and any portion of the record can be repeated with the same ease as that provided by wax cylinders. By reason of the fact that the film is preferably made of cellulose acetate, the record is extremely durable and may be played hundreds of times with little loss in the high frequencies.

Due to the small difference in diameter between the large and small ends, the slope oi the conical surface is small and thereiore the linear speed does not vary greatly throughout the cone and therefore the frequency characteristic is practically uniform.

In the preferred form the angle between the cone surface at the large end and the radius at this end is not greater than 82.

What I claim is:

A sound record of hard surfaced material, such as a moving picture film, upon the surface of which a sound track may be made, said record being in the form of a hollow truncated cone when in its greatest expanded condition, and being so thin with respect to the diameter of the cone that its form will be varied in ordinary handling.

WILLIAM L. WOOLF.

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