US2254844A

US2254844A - Phonograph

Info

Publication number: US2254844A
Application number: US287292A
Authority: US
Inventors: Emile C Guedon
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1939-07-29
Filing date: 1939-07-29
Publication date: 1941-09-02
Anticipated expiration: 1958-09-02

Description

Sept. 2, 1941. E. c. GUEDON PHONOGRAPH 2 Sheets-Sheet i Filed July 29, 1959 Buvcuto'r mm M SeptQZ, 1941. Y E. c. GUEDON PHONOGRAPH Filed July 29; 1939 2 Sheets-Sheet 2 Patented Sept. 2, 1941 TATES .ATENT FFICE PHONOGH Emile C. Guedon, Audubon, N. .i'., assignor to Radio Corporation of America, a corporation of Delaware Application July 29, 1939, Serial No. 287,292

1 Claim. (Cl. 74-191) graph turntables at the desired speed. This may be due to a number of causes, such as variations in line voltage, variable loads, etc.

The primary object of my present invention is to provide a phonograph turntable drive which can be readily adjusted to provide the desired speed.

More particularly, it is an object of my present invention to provide an improved drive for phonograph turntables which can be readily adjusted to provide correct playing speed for the turntable.

Another object of my present invention is to provide an inexpensive, self-starting, motordriven turntable for the playing of phonograph records.

In accordance with my present invention, I provide a self-starting, electric motor which is pivotally supported on a suitable frame or cradle and which has an approximately vertical drive shaft provided with a conical driving surface. In one form of my invention, I connect a friction wheel to the turntable for rotation therewith and arrange the motor in a manner such that the conical driving surface thereof is in constant engagement with the periphery of the friction wheel, the friction between the conical driving surface and the friction wheel effecting rotation of'the turntable. I also provideadjusting means'for the frame or cradle of the motor so that the motor can be readily adjusted to bring different portions of its conical driving surface into engagement .with the periphery of the friction wheel. In this manner, the speed of the turntable can be readily altered to suit variable loads and variable voltage conditions.

In accordance with another form of my inand couple the pulley to a friction wheel by means of a belt. The motor, as before, is pivotally mounted and has its conical driving surface in constant engagement with the friction wheel which, in this modification, is made adjustable along the conical driving surface to effect variations in speed. The novel features that I consider characteristic of my invention are set forth .with particularity in the appended claim. The invention objects and advantages thereof, will best'be understood from the following description of two embodiments thereof, when read in connection with the accompanyingdrawings, in which Figure 1 is a plan view'of a turntable driving mechanism embodying one form of my invention,

Figure 2 is a sectional view' thereof taken along the line 11-11 of Figure 1,

Figure 3 is a plan view of a phonograph drive mechanism showing another form of my invention, and

Figure 4 is a side elevation of the latter form of my invention.

Referring more particularly to the drawings, wherein similar reference numerals designate corresponding parts throughout, I have shown, in Figures 1 and 2, a motorboar'd l which supports a frame 3 in which is rotatably mounted a spindle 5. Fixed to the spindle 5 is a rubber-tired disk I constituting a friction wheel, the disk I being connected to a turntable 9 by means of a plurality of upstandingpins ll which are received in rubber grommets l3 secured to the turntable 9. This construction may be of the type disclosed, for example, in the U. S. patent to Blessing and Guedon, No. 2,157,158, and serves efiectively to prevent the transmission of vibrations to a record supported on the turntable 9 during playing.

Fixed to the frame 3 are a pair of oppositely disposed brackets l5 formed with knife edges or other suitable fulcrums H on which a motor fventlon, I provide a pulley on the turntable shaft itself, however, both as to its-organization and method of operation, together with additional frame or cradle I9 is pivotally mounted. A suitable electric motor 2|, preferably of the selfstarting type, and having a driving shaft 23 provided with a conical driving surface or tip 23a,

is pivotally carried by the cradle or frame IS on a pair of oppositely disposed pins 25, the shaft 23 being disposed between the fulcrums l1 and, the pivot pins 25. The center of gravity of the motor 2l is located to the left of the pivotal mountings l1 and 25 (as viewed in Fig. 2) so that the motor 2| always tends ,to rotate in a counter-clockwise direction and therefore the conical driving surface 23a will always be maintained in engagement with the periphery of the friction wheel I.

ical driving surface 23a. and the periphery of the rubber-tired friction wheel I will effect rotation of the wheel I and theturntable 9. d To alter the speed of the turntable, an adjusting screw 1 is threaded into the frame 3 and is brought down into engagement with the cross-arm l9a of the cradle l9. As the screw Z'lis advanced in a downward direction, it will effect clockwise rotation of the cradle l9 and the motor 2i about the fulcrums or knife edges I1. This raises the conical driving surface 23a and at the same time tends to move it away from the periphery of the friction wheel 1. However, inasmuch as the center of gravity of the motor 2| is to the left of the pivot'pins 25, it is obvious that the counterclockwise movement of the motor about the pins 25 will offset the corresponding clockwise movement of the motor assembly about the fulcrums l1, and the conical driving surface 230 will still be maintained in engagement with the periphery of the friction wheel 1, although at a larger diameter. This, of course, will increase the speed of the turntable. Conversely, if the adjusting screw 21 is retracted in an upward direction, the cross-arm l9 will follow it, and the motor assembly will pivot around the fulcrums l1 in a counter-clockwise direction to bringa portion of the driving cone 23:; having a smaller diameter into contact with the friction wheel 1 and thereby reduce the speed of the turntable.

In the modification of my invention shown in Figures 3 and 4, the turntable spindle 5 has fixed thereto a pulley 3| which is connected by means,

of a belt 33 to a second pulley 35 rotatably mounted on the bottom extension of the adjusting screw 21 and fixed to a rubber-tired friction wheel 31. An idler pulley 39 carried on a pivotally mounted bracket 4| constantly maintains tension in the belt 33 under the influence of a spring 43.

Pivotally mounted on a bracket 45 is the motor 2| which is constantly biased in a clockwise direction by a spring 41 to maintain the conical driving surface 23a in constant engagement with the friction wheel 31. By merely manipulating the adjusting screw 21 one way or the other, it is obvious that the friction wheel 31 will be moved along the conical driving surface 23a to thereby vary the speed imparted to the friction wheel 31 by the motor and thus to correspondingly vary the speed of the pulley 3| and the turntable mounting.

Although I have shown and'described but two embodiments of my invention, I am fully aware surface, said motor shaft being disposed between the pivotal mounting of said frame and the pivotal mounting of said motor on said frame and the center of gravity of said motor being located on the same side of both of said pivotal mountings whereby said motor constantly tends to swing about both said mountings in a direction to effect engagement between said conical driving surface and said friction wheel, and adjustable means associated with said frame for adjusting said frame about said first named means whereby to vary the point of engagement of said conical surface with said friction wheel to thereby alter the speed imparted to said turntable by said motor.

, FWHLE C. GUEDON.