US2095308A

US2095308A - Phonographic apparatus

Info

Publication number: US2095308A
Application number: US19065A
Authority: US
Inventors: Arthur C Blaney
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1935-04-30
Filing date: 1935-04-30
Publication date: 1937-10-12
Anticipated expiration: 1954-10-12

Description

; A. 'c. BLANEY PHONOGRAPHIC APPARATUS Oct. 12,: 1937.

Filed April 30, 1935 lNVENTOP 7 Arthur C.Blaney BY v fiTTOR/VEY Patented Oct. 12, 1937 PHONOGRAPHIC APP RATUS Arthur C. Blaney, Collingswood, N. J., assignor 'to Radio Corporation of America, a corporation of Delaware Application April 30, 1935, Serial n iaocs 14 Claims. (cl. 179-4003) This invention relates to phonographic apparatus, and more particularly to sound recording and reproducing apparatus of the type employing V a photographic disc whereon the sound is recorded in the form of an uninterrupted spiral,

the present invention being an improvement upon that disclosed and claimed in the co -pendingapplication of Ellsworth D. Cook, Serial No. 704,- Q05, assigned to the Radio 'Cor'poration of America.

In said co-pending application, there is dis closed a phonograph employing a record on which the sound is recordedin the form of an Archimedean spiral track, a stationary light source and associated optical system focusing a fine line of light radially across the record so as to include all the spirals or sound track turns across one radius. On the other side of the record, a stationary photoelectric cell is disposed, the active 7 element of the fcell having a length equal to the length of the radial light line and being in alignment therewith; In order to mask off all the light except that desired at the reproducing point, an opaque mask provided with an Archimedean, transparent spiral is placed adjacent the record so that the spiral record track and the spiral in the mask will have the'same geometrical center. Since the rate of radius change of an Archij medean spiral is constant'throughout its length, it is possible, by choosing a scanning spiral of proper pitch and rotating itv at a suitable speed relative to that of the record, to cause the two spirals to intersect, each other along the aforesaid radial light line, whereby only that portion of record spiral which is in alignment with both the scanning spiral and the light line at any instant will serve to affect the light passing to the photoelectric cell at that instant.

While a system using a scanning mask of. the foregoing type works satisfactorily, it leaves open several sources of noise generation which might be serious enough, at times, to interfere with the proper reproduction of sound. In the first place, since successive transverse portions -of the entire length of the scanning spiral are made use of during the reproduction of a record and since,

even despite the exercise of great care in forming the scanning spiral, it is hardly possible to form a spiral having absolutely uniform width.

throughout itslength, it is obvious that variations in its width along its length will result in a'fmodulation of the reproducing beam not intendedpby the rec ord. Similarly, in the case of a scanning spiral-formed on a photographic disc or platc, if dust or "other, foreign matter should accumulate on the transparent'scanning spiral, the reproducing beam will be unintentionally modulated. Now, if this modulation takes place at a frequency within the audible range, it is obvious that unrecorded and undesirablenoises due entirely to variations in width of or foreign matter upon the scanning spiral will result.

According to another well known form of phonograph of the photographic disc type, the scanning element is in the form of a disc or plate having a small aperture therein and forming a part of an optical housing which is moved radially across the record. Such a system is shown, for example, in the patent to Dirzuweit, No. 865,- 574. With a system of this sort, however, relatively complicated machinery is necessary to ac tuate not only the scanning element, but also the optical system, the light source, and the housing and supporting structure therefor. Moreover, a

system of this sort needs continual resetting and adjustment before it can be used again once a record hasrbeen played. I The. primary object of my invention is to provide improved photo-phonographic apparatus of the disc type which will be free from the foregoing difficulties.

More specifically, it tion to provide improved photo-phonographic apparatus of the disc type from which reproducis an object of my invenin photo-phonographic apparatus of the" type specified, an improved scanning device which will be free from sources of undesirable noise generation.-

A further object of'm'y inventionis to provide an improved scanning device as aforesaid by means of whichany desired number of repetitions of a photographic disc record can be automatically obtained once the apparatus is set in opera tion. It is another object of my invention to provide improved. photo-phonographic apparatus of the disc type from which reproduction of a subsequent record may be had immediately upon the completion of playing 'of a previous one without the necessity of resetting any of the parts other than the replacing of the played record by a new one. r r

Still another object of my invention is to provide, in photo-phonographic apparatus of the type aforesaid, improved scanning means whereby a plurality of recordings upon a single disc may be either successively, simultaneously or alternately reproduced.

A further object of my invention is to provide improved record scanning means for photographic disc records by means of which a predetermined time interval between successive reproductions may be arranged.

A still further object of my invention is to provide, in photo-phonographic apparatus of the type specified, improved scanning means which is simple in construction, inexpensive of manufacture, and highly efficient in use.

The novel features of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following de scription of a specific embodiment thereof, when taken in connection with the accompanying drawing, in which Figure 1' is a side elevation of one form of my invention, Y

Figure 2 is a iew taken on the line 22 of Figure 1, and I Figure 3is a view. taken on the line 33 of Figure 1.

7 Referring more specifically to, the drawing, wherein like reference characters designate corresponding parts throughout, there is shown a motor plate I on which is supported a motor 3 which drives a turntable supporting spindle 5,

. the turntable I being made of a transparent material and supporting a'photographic record 9 having a 'spiral'sound track thereon. The upper end of the spindle 5 may be threaded, if desired, for the reception of a nut I I which, in cooperation with a friction disc I3, serves to securely clamp the record 9 on the turntable "I.

Fixed to the'spindle 5 is a gear I5 which meshes with and drives a gear "I1 fixed to a stub shaft I9 adjacent the spindle 5. The shaft I 9 has a worm 2I formed thereon forv driving a gear 23 on a shaft 25 toYwhich is fixed a bevel gear 21, in turn driving bevel gear 29 on a shaft 3 I at a speed greatly reduced from that of the spindle 5 for a purpose which will appear, presently. The shaft 3| is carried by abracket member 33 and has fixed thereto a; sprocket 35. Also carried by the bracket 33 is a second shaft 31 which has a sprocket 39 fixed thereto, an endless opaque scanning belt 4I having a number of scanning sections or apertures 43 formed therein at spaced points being trained around and driven by the

sprockets

35 and 39. If desired, the

sprockets

35 and 39 may be replaced by ordinary friction rollers, but I preferably use sprockets in order to prevent slippage of the belt 4| relative to the record 9.

The sprockets 35 and39 are arranged to move the belt radially across the record 9 under the turntable I, as clearly shown in Figure 1, the speed of the belt driving sprocket 35 being such that it will advance the belt 4| at the same rate as that at which the spiral sound track moves radially inwardly as the record 9 rotates. It is for this reason that the shaft 3 I must be rotated at a much slower speed than the spindle 5. A fixed. optical system within "a casing 45. is suitably arranged to form a fine line of light radially across the record in alignment with (that is, in the same vertical plane with) the apertures 43. As the belt M is advanced by the sprocket 35, one of'its apertures 43 will serve, to scan the spiral record soundtrack along its length and the modulate'gl light passing through both the sound track and the active scanning aperture 43 at any particular instant will serve to affect a photoelectric cell 41 preferably mounted on an upturned portion 49 of the bracket or mounting member 33 within the belt 4| and having an active element at least as long as the radial light line on the record. Since the area of the active aperture 43 which may be operating at any time is always constant and since it moves very, very slowly, it is obvious that no modulation of the light beam will be produced thereby and hence noundesirable noises will be generated on account of it.

The bracket member 33 is preferably split as at 34 and formed with a central slot through which the screws 49 extend for adjustably securing it to the motor plate I, so that it may be adjusted radially of the record in order to apply adequate tension to the belt 4! and to facilitate bringing the apertures 43 into proper scanning relation with the record. For a record having but a single spiral sound track, the apertures 43 should be spaced a distance just slightly greater than the greatest radial distance across the sound track spirals, so that repetition of the selection will be automatically obtained by the next succeeding aperture becoming active as soon as the preceding one has become inactive. By spacing the apertures 43 a greater distance apart, a predetermined time interval may be arranged between successive playings. Where a record is employed having two or more concentric spiral tracks thereon, the apertures 43 may be so arranged that first one and then another selection may be played, or so that all may be played simul: taneously or alternately, as desired. The particular spacing of the apertures may be made to suit any occasion or set of conditions, thus making my improved phonograph very useful in many fields such as radio broadcasting, advertising, etc.

Although I have shown and described but one form of my invention, it will be obvious to those skilled in the art that many other modifications thereof are possible. For example, if found desirable, both

sprockets

35 and 39 may be directly driven from the shaft 25 without making the bracket 33 adjustable as described. The belt 4I may be made of metal, leather, or any other suitable material and the apertures 43 may be cut out, stamped or otherwise formed therein, or the belt 4| may be photographically formed to provide transparent sections 4| therein. In any event, I desire that my invention shall not be limited except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In photo-phonographic apparatus, the combination of a rotatable record having a spiral sound track thereon, and a scanning element comprising an opaque endless belt associated with said record and having at least one transparent scanning section therein, said belt being arranged to move radially across said record whereby to cause said section to scan said sound track.

2. In photo-phonographic apparatus, the combination of a rotatable record having a spiral sound track thereon, a scanning element comprising an opaque endless belt associated with said record and having at least one scanning aperture therein, said belt being arranged to move and carry said aperture radially across said record whereby to scan said sound track, and stationary means for supplying a fixed line of light radially across said sound track in alignment with the path of movement of said aperture.

3. In photo-phonographic apparatus, the combination of a rotatable record having a spiral sound track thereon, a scanning member associated with said record and movable radially thereacross, said scanning member comprising an opaque endless belt having a plurality of scanning apertures therein, andstationary means for supplying a fixed line of light across said sound track, said scanning member and said stationary means being so arranged relative to the record that said scanning apertures and said light line all lie in a common plane.

4. The invention set forth in claim 3 characterized in that said scanning apertures are spaced apart a distance at least as great as the greatest radial distance across the spiral sound track.

5. The invention set forth in claim 3 characterized in that said scanning apertures are spaced apart a distance such that a predetermined time interval will elapse between successive reproductions of the record.

6. In photo-phonographic apparatus, the combination of a rotatable record having a plurality of concentric spiral sound tracks thereon, and a scanning member associated with said record and movable radially across each of said spiral sound tracks, said scanning member' comprising an opaque member having a plurality of scanning sections therein so spaced apart that each of said sound tracks has at least one scanning section associated therewith for scanning the respective sound tracks as said scanning member moves radially thereacross.

8. The invention set forth in claim I characterized in that said scanning apertures are further so spaced apart that each of said sound tracks will be reproduced successively.

9.,The invention set forth in claim '7 characterized inthat said scanning apertures are further so spaced apart that each of said sound tracks will be reproduced alternately.

10. The invention set forth in claim 7 characterized in that said scanning apertures are further so spaced apart that all of said sound tracks will be reproduced simultaneously.

11. In photo-phonographic apparatus, the combination of a record having a spiral sound track thereon, a, scanning member comprising an endless opaque belt having a scanning section therein, a pair of rollers around which said belt is trained for movement radially across said rec- 'ord, andrneans coupling said motor to said record and to at least one of said rollers whereby to provide driving connection therebetween.

12. The invention set forth in claim 11 characterized by the addition of means for preventing the slipping of said belt on said rollers relative to said record.

13L Inphono-photographic apparatus, the combination of a record having a spiral sound track thereon, a scanning member comprising an endless opaque belt having a scanning section therein, a mounting member, a pair of rollers supported by said mounting member and around which said belt is trained for movement radially across said record, means whereby said mounting member is adjustable radially of said record, and means coupling said motor to said record and to at least one of said rollers whereby to provide driving connection therebetween.

14. In photo-phonographic apparatus, a scanning device for scanning a spiral sound track, said device comprising an endless member having a plurality of scanning apertures therein adapted to cooperate with said sound track.

ARTHUR o. BLANEY.