US2338414A - System for guiding mechanical sound records - Google Patents

Description

Jan. 4, 1944. A. w. DE SART, SR, ETAL 2,333,414

SYSTEM FOR GUIDING MECHANICAL SOUND RECORDS Filed Jan. 7, 19 41- DRIVING MECHANISM FQEDEQ/CA ft 6205.

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Patented Jan. 4, 1944' SYSTEM FOR GUIDING MECHANICAL SOUND RECORDS Albert W. De Sart, Sr., and Frederick F. Brush, Los Angeles, Calif., minors to United Acoustigraph Corporation, Los Angeles, Call! a corporation oi Nevada Application January 7, 1941, Serial No. 373,398

4 Claims. (Cl. 74-240) This invention relates to mechanical sound records, and more particularly to records made in the form of an elongated flexible member such as a loop, adapted to be driven and guided by a plurality of rollers.

Loops 01' this character are made from material that may be embossed or engraved to form the sound track; and they must be sufllciently flexible to be readily conformable to the rollers over which they run. These conditions are quite well fulfilled by making the flexible member from synthetic material such ascellulose acetate and not more than 0.015 inch thick. The sound track of course must be so arranged that the groove of the track does not sever the material. And in order to provide a long playing record, the loop is long, and so arranged that both sides thereof may be utilized.

Since the sound track, due to these requirements is exceedingly shallow, the stylus cooperating therewith for reproduction must be moved positively by a traversing drive (usually in the form of a. fine pitch lead screw) which moves the stylus across the loop as the loop is moved in a direction longitudinally of its length. For accurate reproduction, then, it is required that theloop be restrained against any appreciable sidewise motion, both during recording as well as reproducing.

In order to make this result possible an edge of the loop may be utilized as a guiding element for maintaining the loop in accurate recording and reproducing alinement. The edge therefore is made precisely straight and will serve to direct the sound track when the record is located on one side; and the opposite edge, also made precisely straight is utilized when the sound track is located on the other surface of the loop. In this way, accurate tracking of the stylus is ensured independently of the record groove.

It is one of the objects of this invention to make it possible in a simple manner to aline the loop so that its axial position on the rollerthat cooperates with the stylus may be maintained.

In order further to ensure that the record member will be maintained at all times in accurate alinement with the stylus, the member is preferably formed as an integral loop, having no overlapping or spliced ends. another object of this invention to ensure accurate running of a loop or this endless character.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration or several embodiments oi the invention. For this It is accordinglypurpose there are shown a few forms in the drawing accompanying and i'o'rming part of the present specification. These forms will now be described in detail, illustrating the general principles of 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 this invention is best defined by the appended claims.

Referring to the drawing:

Figure 1 is a side elevation of a system incorporating the invention, the flexible element being partially cut away to reduce the size of the figure;

Fig. 2 is a sectional view taken along plane 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 2 of a modified form of the invention; and

Fig.4 is an enlarged detail section taken along the plane 4-4 cr Fig.3.

In the form of the invention illustrated in Figs. 1 and 2, the flexible record carrying member I is shown in the form of an endless loop. This record carrier may be of any desired length. It is intended to be capable of carrying a. record that is made on one side, and then on the other side by turning the loop inside out. This member l is suiiici'ently thin, so that it may flex around and over the rollers such as the driving roller 2 and a guiding roller 3. For this purpose it should not exceed .015 inch in thickness and is preferably made of material such as a synthetic resin or the like, or a cellulose acetate or its equivalent. Preferably also the loop is formed as one integral whole without any overlapping or abuttingspliced ends. In this way it is assured that the sound track illustrated diagrammatically by the reference character 4 will be continuous without any tendency for the stylus 5 to jump the track as it would pass over the spliced ends. is in the form of a continuous shallow groove formed as by embossing, accomplished by the pressure exerted on the record member, by the stylus 5. Ordinarily a lateral record is preferred: i. e. one in which the stylus vibrations occur in a direction lateral of the groove 4.

This stylus 5 is shown as supported in a head 6, which may be either a recording or reproducin: head.

The roller 2 in this instance is shown as being driven by any appropriate drive mechanism 1, such as a clock spring or electric motor. This drive is correlated with the drive of the head 6 in such manner that the stylus 5 is simultaneously advanced transversely of the flexible member I.

The stylus 5 forms the sound track 4 or it mayserve to reproduce sound from a previously formed The track 4 v track 4. The roller 2 serves as an anvil or support for the record loop with respect to the stylus 5. The transverse motion of th head 8 is such that two adjacent portions of the track 4 are spaced very closely together.

It is essential that the flexible member I retain its definite axial position with respect to the driving roller 2, so that the stylus when recording will form a track presenting no irregularities of position. Accordin ly, when reproducing, the same precautions are necessary, so that there be no severe lateral strain on the stylus 5 nor any material tendency for the stylus to ump the track. For this purpose both of the longitudinal edges 8 and 9 of member I are made as nearly true as practicable; and may, if desired, be parallel to each other; and either edge, such as 8, is maintained in contact with an abutment on the roller 2, such a the flange I0. Provisions are made for constantly urging the member I in a direction illustrated by the arrow II and against the abutment III. This may be accomplished in a number of ways.

For example, the axes I2 and I3 of the driving and guiding rollers 2 and 3 may be placed slightly out of exact parallelism, and in such a direction as to crowd the flexibl member I toward the left. Such departure from true parallelism is indicated, for example, by the dotted line 25 in Fig. 1, the departure being exaggerated for clarity. This departure from exact parallelism may be accomplished either by adjusting the axis I2 or the axis I3, as by appropriate adjustment of the support upon which the roller to be adjusted is mounted. This may for example be readily accomplished by angular adjustment of the entire driving and recording or reproducing elements in a direction about an axis transverse to the axes of the rollers. There is sufiicient yielding permitted by th material forming the flexible member I as to permit this misalinement and yet maintain the flexible member I in contact with both rollers 2 and 3. The separation of the axes l2 and I3 is sufficient to maintain the member I in slight tension, so that a drive may be effected.

The flexible member I is intended to be utilized on both sides, and if the loop i reversed from the position shown, the longitudinal edge 9 would then become active against the abutment II). The roller 2, which serves to cooperate with the stylus 5, is made of appropriate material capable of serving as an anvil against which the pressure of the stylus 5 may be exerted, and is therefore made of true cylindrical form.

In the form of the invention illustrated in Figs. 3 and 4 the flexible member I4 is shown as of indefinite length. Its lower reaches may be accommodated in an unconfined manner in an appropriate place; or guide rollers I5, I6, I! and I8 of conventional cylindrical form may be provided. Under any circumstances some provision is made for keeping the member l4 in tension over the driving roller I9 which may be driven in the same manner as the driving roller 2 of the form previously described.

In this instance the abutment or flange 20 on the roller I9 serves the same purpose as the abutment I0 shown in Fig. 1. Crowding or urging of the flexible member l4 toward the flange 20 is accomplished in this instance by the provision of the guide rollers 2| and 22 oi'crown form. As illustrated most clearly in Fig. 4, the crest of the crown on the rollers 2| and 22 is disposed in a plane 23 normal to the roller axis; said plane being displaced from the center line 24 of the flexible member I4 in the direction in which it is desired to urge this, flexible member. shown exaggerated in Fig. 4.

A the flexible member I4 rides over the crowned guide rollers 2I and 22, these rollers tend ment 20.

By the means illustrated and described-the flexible record carrying member I or I4 is maintained in accurate axial alinement, making it possible for the stylus 5 to follow or form the sound grooves 4 accurately.

What is claimed is:

1. In a system for driving and guiding an elongated flexible member capable of carrying a sound record, a driving roller over which said member passes, and having an abutment for restraining movement of said member in a direction transverse to the motion of the member, and a guide roller having a crown surface acting to urge said member against said abutment.

2. In combination, a thin flexible loop capable of carrying a sound record, said p having an edge that is relatively precise with respect to the record, a roller over which the loop passes for cooperation with sound translation equipment, said roller having an abutment contacting said edge, and forming the sole edge-contacting surface for determining the lateral position of the loop, and mean constantly urging said edge laterally into continuous engagement with said abutment.

3. In combination, a thin flexible loop capable of carrying a sound record, said loop having an edge that is relatively precise with respect to the record, a roller over which the loop passes for cooperation with sound translation equipment, said r oller having an abutment contacting said edge, and forming the sole edge-contacting surface for determining the lateral position of the loop, and 'a guide roller acting upon the loop to urge the loop constantly in a lateral direction into constant engagement with said abutment.

4. In combination, a thin flexible loop capable of carrying a sound record, said loop having an edge that is relatively precise with respect to the record, a roller over which the loop passes for cooperation with sound translation equipment, said roller having an abutment contacting said edge, and forming the sole edge-contacting surface for determining the lateral position of the loop, and a guide roller having an axis so arranged as to cause the loop to be constantly urged laterally into continuous engagement with said abutment.

ALBERT W. DE SART, SR. FREDERICK F. BRUSH.

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