US2106710A

US2106710A - Phonograph turntable driving mechanism

Info

Publication number: US2106710A
Application number: US592704A
Authority: US
Inventors: Frederick C Barton
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1932-02-13
Filing date: 1932-02-13
Publication date: 1938-02-01
Anticipated expiration: 1955-02-01

Description

Feb. l, 1938.l F Q BARTON 2,106,710

PHoNoGRAPH TURNTABLE DRIVING MECHANISM Filed Feb. 13, 1952 IN VEN TOR.

Patented Feb. 1, I 1938 UNTE STATES oFFIClV PHONOGRAPH TURNTABLE DRIVING MECHANISM tion of Delaware Application February 13, 19,32, Serial No. 592,704

15 Claims.

My invention relates to phonograph turntable driving mechanism and, more particularly, is an improvement over the invention disclosed in the co-pending application of Benjamin R. Carson,

Serial No. 512,244, filed January 30, 1931, and

assigned to Radio Corporation of America.

In reproducing sound from phonograph records of the disc type, it is necessary to rotate the disc at a constant, predetermined speed. Heretofore,

l0 the speed of the usual phonograph record was '78 to 80` R. P. M. but there recently have been lntroduced phonograph disc records which require a speed of approximately 331A; R. P. M. Obviously, if a phonograph is to have commercial merit, it must be so designed that records of either of the aforesaid types may be reproduced thereby, at will.

In the Carson application, speed changing mechanism of the type including a plurality of gears is disclosed, together with means whereby,

through proper manipulation-of an adjusting element, the record supporting platen may be caused to rotate at 78 or 331/3 R. P. M. Mechanisms of the Carson type have gone into extensive public use and have, in general, given a fair degree of satisfaction. It has been noticed, however, by those who are extremely critical, that the gear teeth in the said Carson mechanism tend to introduce minor irregularities into the rotation of the disc, which irregularities cause wows, or, in other words, momentary changes of pitch of the reproduced sounds.

It is, accordingly, an object of my invention to provide a reducing gear for phonograph mechanism that shall be smoother in action than the reducing gears of the Carson type heretofore known.

It is a further object of my invention to provide mechanism of the type described that shall enable the reproduction of sounds from slowspeed records without the introduction of objectionable wows.

It isa further and more specic object of my invention to provide mechanism of the type described that shall be devoid of gears.

In accordance'with my invention, I provide a phonograph having a. driving spindle adapted to rotate at 78 R.: P. M., to which is attached ari inner ball race. I further provide an outer ball race which, at will, may be held stationaryand,

in addition, I provide a ball retaining cage having means aixed thereto whereby motion thereof may be transmitted to a phonograph turntable. Inv addition, I provide a speed controlling device whereby thev outer ball race may be rei ball retaining cage.

leased, at will, and the inner ball race may be coupled to either the ball retaining cage or the loutside race for the purpose of transmittmg motion to the super-incumbent turntable at '78 R. P. M.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional 10 objects and advantages thereof, will best be understood from vthe following description of a specific embodiment, when read in connection with the accompanying drawing, wherein the single gure is a view in vertical cross-section of 15 phonograph turntable speed changing mechanism comprising a preferred embodiment of my invention.

Referring to the drawing, my improved mechanism comprises a phonograph turntable i havidg a, depending boss 3 provided with a transverse keyway, or slot, 5 into which extends a transverse pin l carried by a driven spindle 9. A bearing Il, of any suitable type, may be provided, whereby the weight of the ydriven spindle 25 and the turntable is supported.

'Ihe driven spindle has a ball retaining cage I3 aiixed thereto and depending therefrom. A plurality of balls l5 are provided which are maintained in Vspaced relation by the depending 30 An inner ball race Il is'v ailixed to the upper end of a driving vspindle I9 co-axial with the rst referred to spindle 9, the said driving spindle being operatively connected to a prime mover, such as a motor M, for rota- 35 tion at 78 R. P. M. An outer ball race 2| is provided, to which is affixed a depending element 23.

i The depending element may take the i'orm of an annular flange completely encircling the outer ball race and being provided with a plurality of 40 inwardly directed gear teeth, or it may be a single detent device, as illustrated.

Obviously, if the outer ball race is prevented from rotating, rotary motion from the inner ball race will be transmitted to the balls in the re- 45 tainer l 3, and the said ball retainer will be caused to rotate at a speed determined by the relative diametersv of the balls and the innerball race. 'In order that the outer ball race may be held against rotation, I provide a pivoted lever 24, 50 having a attenedend portion 25, which, when the lever is raised, moves into engagement with the 4depending velement 23 to restrain it from rotating. A supporting device 21 may also be pro-1v vided, having a slotted end 29 into which the end 55 In the event that it is desired to rotate the turntable at '78 R. P. M., it is, of course, necessary to release the outer ball race and to lock the inner and outer races together, as heretofore explained. For this purpose, I provide a collar 3l slidably mounted on the lower driving spindle I9 and so dispose another end portion 33 of the aforementioned operatinglever that the collar may be moved axially of the said spindle. The collar is provided wtih a pin 35 which extends outwardly into the path of the element depending from the outer ball race. When the lever is depressed to the position shownin the drawing, the outer ball race is released and the pin carried by the collar engages the depending element23 and thus effectively locks the inner spindle to the outer ball race.

Inasmuch as the relative sizes of the several ball races and the diameters of the balls, themselves, may be readily calculated by anyone skilled in machine design who is provided with the necessary handbooks, it is my opinion that detailed calculations need not be given in order to render my disclosure complete.

. It will be apparent, from the foregoing disclosure of my improved phonograph platen driving mechanism that, through its utilization, turntable speeds of either 78 or 331/3 R. P. M. may be had at will. It should further be apparent that, inasmuch as all gearing has been omitted, the turntable, when rotating at, 331/3 R. P. M., will be extremelysteady and its speed will not vary in a manner to introduce wows.

Although I have shown and described a specic embodiment of my invention, I am fully aware that many modifications thereof will be readily apparent to those skilled in the art to which it pertains. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and. by the spirit of the appended claims.

I claim as my invention:

1. In combination, a phonograph record supporting platen, a spindle adapted to be driven at a definite speed, speed changing mechanism of the planetary type frictionally geared to the spindle and positioned between said spindle and said platen, and means for restraining from rotating, at will, a portion of said mechanism.

2. In combination, a spindle adapted to be ro- 'tated at av predetermined speed, planetary gear mechanism comprising a plurality of ball races and a plurality of balls associated therewith carried by said spindle, a record driving spindle and a ball spacing cage depending from said spindle and adapted to cooperate with the said balls to transmit motion to said turntable driving spindle.

3. The invention set forth in claim 2 characterized in that means are provided for, at will, effectively locking said ball races together, to prevent relative motion-therebetween.

4. The invention set forth in claim 2 characterized in that means are provided whereby-the lower spindle may be, at will, effectively locked to the outer race.

5; As an article of manufacture. a record platen supporting and driving spindle provided with a depending ball spacing cage.

6. In combination, a spindle adapted to be driven ata predetermined speed, a record platen supporting spindle, motion transmitting means of the planetary type jointly carriedlby said spindles, and means for, at will, locking a portion of said motion transmitting means against rotation 7. The invention set forth in claim 6 characterized in that means are provided whereby said motion transmitting spindle may be operatively and immediately connected to a portion of said motion transmitting mechanism.

8. In combination, a driving spindle, a driven spindle, motion transmitting mechanism of the planetary type jointly carried by said spindles, said mechanism comprising an inner ball race carried by the driving spindle, a ball spacing cage carried by the driven spindle, and an outer ball race disposed in operative relation to said ball spacing cage and said inner race.

9. In combination, a spindle adapted to be driven at a definite speed, a turntable supporting and driving spindle, power transmission means of the planetary ball type frictionally geared to said first-named spindle, power take-off means carried by and depending from said turntable spindle and adapted to cooperate with the balls of said transmitting means whereby said first and second named spindles are indirectly coupled together, and means for locking a portion of said transmission means against rotation at -will to cause said turntable spindle to rotate'relatively to said first-named spindle.

10. The combination with a phonograph turntable adapted to rotate records of different reproducing speeds, of a motor for driving said turntable, a shaft driven by said motor at a predetermined speed having a driving member on the end thereof, a spindle connected with said turntable having a driven member mounted thereon, said driven member being adapted to embrace said driving member, a plurality of balls mounted for rotation in said driven member adapted to be engaged and rotated by said driving member, and means for clamping said balls in non-rotating position for locking with said driving member whereby said turntable will be directly driven'thereby, and release said balls for permitting rotating movementfthereof whereby said driven member will be indirectly driven therethrough for rotating said turntable at a slower speed. y

11. The combination with a phonograph turntable adapted to`rotate records of different reproducing speeds, of a motor for driving said turntable, a. shaft driven by said motor at a predetermined speed having a driving member on the end thereof, a spindle connected with said turntable having a driven member mounted thereon, said driven member being adapted to embrace said driving member, a plurality of balls mounted for rotation in said driven member adapted to be engaged and rotated by' said driving member, means for clamping said balls in non-rotating position for locking with said driving member whereby said turntable will be directly driven thereby, and release said balls for permitting rotating movement thereof whereby said driven member will be indirectly driven therethrough for rotating said turntable at a slower speed, and manually operated means for altering the driving function of said balls as above set forth.

12. The combination with a phonograph turntable adapted to rotate records of different reproducing speeds, of a motor for driving said lturntable, a shaft driven by said motor at a thereon, said driven member being adapted to embrace said driving member,y a plurality of balls mounted for rotation in`said driven member adapted to be engaged and rotated by said driving member, and a ball race adapted to be locked with said balls and driven member for causing said driven member to be directly driven therethrough and unlocked therefrom to provide a ball race for said balls for obtaining a slower speed.

13. The combination with a phonograph turntable adapted to rotate records of different reproducing speeds, of a motor. for driving said turntable, a shaft driven by said motor at a predetermined speed having a driving member on the end thereof, a spindle connected with said turntable having a driven member mounted thereon, said driven member being adapted to embrace said driving member, a plurality of balls mounted for rotation in said driven member adapted to be engaged and rotated by said driving member, a ball race adapted to be locked with table adapted to rotate records of different reproducing speeds, of a motor for driving said turntable, a shaft driven by said motor at a predetermined speed having a driving member on the end thereof, a spindle connected with said turntable having 'a driven vmember mounted thereon, said driven member being adapted to embrace said driving member, a stationary support for said turntable and spindle, a plurality of balls mounted for rotation in said driven member adapted to be engaged and rotated by said driving member, a ball race' adapted to be locked with said balls and driven member for causing said driven member to be directly driven therethrough and unlocked therefrom to provide a ball race for said balls for obtaining a slower speed, and a clutch member for locking said race with said driving member while releasing it from the support when said clutch is in one position and when in the otherposition lockingthe same with said support while releasing it from said driven member.

15. The combination with a phonograph turntable adapted to rotate records of different reproducing speeds, of a motor for driving said turntable, a drive shaft driven by said motor at a predetermined speed of rotation, means for frictionally connecting said turntable with said drive shaft whereby said turntable will be directly driven at the same speed of rotation, and means for releasing said frictional contact and applying iii-piace thereof a diierential speed transmission for imparting to said turntable a decreased speed of rotation.

FREDERICK C. BARTON.