US2961882A - Phonograph drive mechanism - Google Patents

Description

2 Sheets-Sheet 1 JNVENTOR. f/e/ae f Z. Harfmax; BY

ATTORNEYS.

Nov. 29, 1960 H. HARTMAN PHONOGRAPH DRIVE MECHANISM Filed Dec. 12, 1958 Nov. 29, 1960 H. HARTMAN PHONOGRAPH DRIVE MECHANISM 2 Sheets-Sheet 2- Filed Dec. 12, 1958 IN V EN TOR.

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2,961,882 PHONOGRAPH DRIVE-MECHANISM Herbert L. Hartman, Elyria, Ohio, ass'ignor to The General Industries Company, Elyria, Ohio, a corporation of Ohio Filed Dec. 12, 11958, Sen-(No. 779,882

'21Claims. (Cl. 74-200) My invention relates "to plural speed phonograph turntable driving mechanisms and relates more particularly to improvements in the selecting or controlling means for such speed changes.

' An object of my invention is to provide improved means for manually selecting and effecting the drive of a phonograph turntable at a desired speed.

A further object of my invention is to provide speed change control means for a phonograph having the control member thereof centrally disposed with respect to the turntable.

A still further object of my invention is to provide a device as set forth above which is readily ,shiftable todrive the turntable at 'a given speed whilethe driving mechanism is in operation.

Yet another object of my i'nventionis to provide such a mechanism which is shift'ab-le by means associated with the spindle-regardless of whether or not a record is mounted upon said spindle.

Another object of my invention is to provide a device as set forth above which includes speed indicating means on the spindle located controller.

A still further object of my invention is to provide a phonograph turntable driving mechanism of the above type wherein all of the operating parts thereof, including the turntable spindle, are adaptable to be unitarily mounted upon a single mounting member.

Another object of my invention is to provide a device of the type referred to which is compact, comprised of but few parts, inexpensive, and highly durable and efficient in use.

These and other further objects of my invention will become readily apparent from the following specification and the appended drawings, in which said drawings:

Fig. 1 is a top plan view of the turntable drive mechanism of my invention showing the turntable associated therewith in partial section;

Fig. 2 is a side plan view of the device of Fig. 1 showing the turntable and the primary mounting plate in section; v

Fig. 3 is a sectional view taken along the line 33 of Fig. 1;

Fig. 4 is a sectional view taken along the line 44 of Fig. 3; and

Fig. 5 is a view taken along the line 55 of Fig. 3.

My invention which comprises speed selecting and control means preferably associated with a turntable spindle is applied, in the form illustrated herein, to a plural-speed turntable driving mechanism generally of the type adapted to drive a turntable having a circumferentially continuous depending flange by means of a spring biased, horizontally floating idler wheel interposed between a vertically disposed rotor shaft having a plurality of pulley drive portions of different diameters thereon and the said turntable flange. The idler wheel shown herein is provided with a vertically, as well as horizontally, movable mount whereby said idler wheel can be disposed at the different levels of the pulley driving portion toeifectdesired speed changes.

According to the modification shown, the vertical movement of the idler wheel mount and, therefore, of the idler wheel is accomplished preferably through means of a longitudinally movable, vertically disposed control rod associated with the turntable spindle. It is also'within the scope of my invention to differently dispose the turntable driving means whereby the vertical movement of the control rod is adapted, through appropriate linkage, to move a portion or portions of the speed transmission mechanism in a direction other than vertical to effect a speed change in the turntable. The modification as illustrated and described herein is an example of one simple and effective way to apply the principle of the present invention.

Referring now to the figures of the drawing in all of which like parts are designated by like reference characters, at 1 I show a primary mounting plate having a portion thereof cut way as shown at 2. The cut away portion 2 forms an irregular aperture in the primary mounting plate 1 within which the phonograph turntable driving mechanism of my invention is positioned.

The phonograph turntable driving mechanism comprises, generally, a motor mounting plate 4, a motor suspended from the lower side of said motor mounting plate as indicated at M in Fig. 2, an upwardly projecting rotor shaft extending upwardly through the motor mounting plate 4, and a horizontally movable idler wheel indicated at 6. The motor mounting plate 4 is provided with up .wardly ofiset, outwardly projecting brace members 7, 8 and 9, the brace member 9 having mounted thereon a turntable spindle 12. The shape of the aperture 2 in the primary mounting plate 1 'is such that the spindle 1 2 and all other operating parts associated with the mounting plate 4 are exposed when said motor mounting plate is secured to the primary mounting plate 1.

As well shown in Fig. 1, it will be noted that the brace members 7 and 8 project outwardly beyond the aperture 2 and that portions of the brace member 9 also extend outwardly under said primary mounting plate. The motor mounting plate 4 is secured to the primary mounting plate 1 by means of bolts and nuts 11 and 11a respectively projected through rubber grommets 10 seated in said brace members. By referring to Fig. 2, it will be noted that the rubber grommet 10 provides spacing means between the motor mounting plate 4 and the primary mounting plate 1 whereby said motor mounting plate is resiliently maintained in place and cushioned against the transference of sound and vibration between said primary and motor mounting plates in a well-known manner.

The motor M is resiliently suspended from the motor mounting plate 4 by means of bolts 13 projecting downwardly through rubber grommets 14 positioned on top of the motor mounting plate 4, said bolts 13 extending downwardly through the motor M andhaving nuts 13a thread fitted upon the lower end thereof. The motor M is so positioned that the armature shaft thereof is disposed in a vertical position. The rotor shaft 5 comprises an upwardly directed extension of said armature shaft and projects upwardly through the motor mounting plate a by means of an aperture 15 in said motor mounting plate. The uppermost end of said rotor shaft is provided with preferably four upwardly, inwardly stepped pulley driving portions 20, 21, 22 and 23. The pulley driving portions 20, 21, 22, and 23 are adapted to drive a turntable 16, rotatably mounted upon the spindle 12, through the medium of the idler wheel 6 which is adapted to resiliently and concurrently peripherally engage one off said pulley driving portions and the depending circumferential flange 17 of the turntable. Said pulley driving portion may be adapted to drive the turntable 16 at any desired speed, and in the embodiment of my invention as herein illustrated and described, the pulley driving portion 20 drives the turntable at 78 r.p.m.s, the pulley driving portion 21 drives the turntable at 45 r.p.m.s, the pulley driving portion 22 drives the turntable at 33 r.p.m.s, and the pulley driving portion 23 drives the turntable at 16 r.p.m.s.

Referring now to Fig. 3, the idler wheel 6 is mounted for vertical as well as horizontal movement whereby it is adapted to contact the different pulley drive portions at the different levels thereof To accomplish the necessary movement, the idler wheel 6 is rotatably mounted upon one end of a pivoted arm 25, said arm being pivoted at the end thereof opposite the idler wheel 6 to the lowermost surface of a toggle link 30. The toggle link 30 comprises a pair of axially parallel, laterally interspaced, bearing portions, a relatively larger and axially longer bearing 31 and a relatively smaller bearing 32. The larger bearing 31 is pivotally mounted upon the motor mounting plate 4 by means of a vertically upwardly projecting pivot pin 33. The pivot pin 33 is rigidly secured to the motor mounting plate 4 in any suitable manner, such as being riveted thereto as indicated at 33a, and extends upwardly a substantial distance above the upwardly directed end of the large bearing 31. The uppermost end of said pivot pin 33 is provided with stop means whereby the toggle link 30 is retained upon said pivot pin said stop means being in the form of a radially outwardly projecting snap ring or washer 34 seated within a circumferential groove 33b of said pivot pin.

The parallel bearings 31 and 32 are integrally connected by means of a web portion 35, and the relatively smaller bearing 32 is spaced substantially upwardly from the motor mounting plate 4 when the relatively larger bearing 31 is seated upon said mounting plate. The arm 25 is provided at the end thereof opposite the idler wheel 6 with a vertically upwardly projecting journal 26 adapted to slidably interfit the bearing 32 and be retained therein by means of a snap ring 27 seated within a circumferential groove 26a adjacent the uppermost end of said journal. The idler wheel 6 is rotatably mounted upon the opposite end of the arm 25 by means of a rigidly mounted, vertically upwardly projecting journal 28.

It will be understood from the foregoing description and by reference to the drawings, particularly Figs. 1 and 3, that the idler wheel 6 is horizontally, pivotally movable about the journal 26 and that said journal 26 is in turn, horizontally movable about the pivot pin 33 by means of the toggle link 30. As best shown in Fig. 1, the idler wheel 6 is freely movable in any direction in a horizontal plane due to the articulation of the toggle link 30 and the arm 25, said idler wheel being also vertically movable to a limited degree by means of the longitudinally slidable bearing 31 telescoped over the pivot pin 33. The idler wheel 6 is resiliently biased into simultaneous peripheral engagement with both the turntable flange 17 and the rotor shaft by means of a coil spring 36 anchored to an upwardly projecting lug 3 of the motor mounting plate 4 at one end of said spring, the opposite end of said spring being anchored to a laterally projecting finger portion 25a of the arm 25 adjacent the journal 28.

It will be noted, therefore, that the idler wheel 6 drives the turntable 16 by means of frictional engagement of its periphery with the turntable flange 17, said idler wheel being in turn driven by whichever of the pulley drive portions of the rotor shaft 5 at whose level said idler wheel is disposed. The idler wheel 6 moves from a lowermost position, as shown in full line in Fig. 3, to the uppermost position shown in dotted lines by sliding over each pulley drive portion step to the successive smaller step, and said idler wheel moves downwardly from the smallest to the largest of said pulley driving portions by climbing over the step to the successive pulley drive portion of larger diameter.

The movement of said idler wheel from one step to another is adapted to be best accomplished while the rotor shaft 5 and the idler wheel 6 are in motion. To facilitate these movements, the idler wheel 6 is provided with a circumferentially continuous resilient tread 6a. The lowermost edge of the tread 6a is circumferentially beveled as shown at 6b. The bevel 6b enables the resilient tread 6a to crawl or climb the pulley drive steps during the downward movement due to the fact that the surface of said bevel contacts the edge of each step obliquely rather than in fiat, abutting relationship. Under these circumstances, the resilient tread 6a moves smoothly from one pulley drive portion to another without bending or distorting said tread.

The means for vertically shifting the idler wheel 6 comprises a shift rod 40 telescopically and slidably projecting through the spindle 12 and having secured to the lowermost end thereof a laterally projecting idler lift cantilever 41. The cantilever 41 projects horizontally from the shift rod 40 as shown at 41a and is right angularly bent to project vertically upwardly through an elongated aperture 4a in the motor mounting plate 4, the uppermost portion of said cantilever being oppositely right angularly bent as shown at 39 to project in the direction of the bearing 31 of the toggle link 30. As best shown in Fig. l, the laterally projecting, upper end 39 of the cantilever 41 is arcuately formed to interfit a circumferentially continuous groove 31a of the bearing 31. It will be readily understood from the foregoing that when the shift rod 40 is vertically moved, the toggle link 30, the arm 25, and the idler wheel 6 are also shifted to a different level by means of the cantilever 41.

The lowermost end of the shift rod 40 is unitarily secured to the cantilever by means of a hub 46. The hub 46 is centrally apertured at 46a and telescoped over the shift rod 40. A set screw 46b is provided in the hub 46 whereby said hub is maintained against vertical displacement upon the shift rod 40. The set screw 46b abuts a reduced portion 40a to prevent such displace ment. The cantilever 41 is secured at the lowermost, horizontally disposed portion 41a to the hub 46 in any suitable manner. As herein illustrated, the lowermost portion 41a is apertured at 41b whereby it is telescoped over an axially extending collar 460 of the hub 46, said collar being bent outwardy to retain the cantilever in place.

Referring now to Fig. 3, the spindle 12 is rotatably mounted within a spindle bearing 50 which bearing is, in turn, rigidly mounted within the brace member 9 of the motor mounting plate 4. Said spindle bearing extends above and below the level of the brace member 9, the uppermost portion thereof, as indicated at 50a, being of relatively larger diameter than the downwardly depending portion, as indicated at 50b. The spindle bearing 50 is provided with an axial bore 51 into which a downwardly directed, diametrically reduced portion 12a of the spindle 12 is adapted to slidably interfit. The axial bore 51 extends downwardly through the spindle bearing 50 to within a short distance of the lowermost end thereof, at which point said bore is diametrically reduced and stepped radially inwardly to form a relatively smaller bore 52.

The spindle 12 is provided with a stepped, axial bore comprising an uppermost, relatively larger socket portion 42 and a lowermost relatively smaller bore 43 coaxial with and of the same diameter as the smaller bore 52 of the spindle bearing 50. The normal diameter of the shift rod 40 is such that it slidably intcrfits the smaller spindle bore 43 and the spindle bearing bore 52, said shift rod having an upper portion of larger diameter as indicated at 44 adapted to slidably interfit and seat in the socket portion 42 of said spindle. Above the upper portion 44 of the shift rod 40 said rod is provided with a manual control knob 45, said control knob having an outwardly radiating shoulder 45a at the circumference thereof adapted to abut the uppermost edge of the spindle 12. The control knob 45 and the upper enlarged portion 44 are provided with fiat surfaces 45b and 44b respectively, said flat surfaces being parallel with the axis of the shift rod 40 and facing in a common direction. As best shown in Figs. 2 and 3, when the shift rod 40 is in its lowermost position whereby the idler wheel 6 is contacting the lowermost pulley driving portion 20, the fiat portion 44b is seated within the socket portion 42 below the uppermost edge of the spindle 12 and the flat portion 45b is exposed above said spindle. The flat portion 45b is provided with a number clearly imprinted upon said surface which indicates the speed at which the turntable 16 will rotate when the shift rod 40 is in its lowermost position. In the form of my invention as it is illustrated and described, the flat portion 45b is imprinted with the number 78 representing 78 r.p.m.s. The flat portion 44b is divided into three sections having three numbers imprinted thereupon, each of said numbers corresponding to the r.p.rn.s at which the turntable will be driven when the shift rod 40 is so positioned that said number is exposed above the uppermost edge of the spindle 12. The numbers as shown herein are successively designated below the figure 78 as 45, 33, and 16. It will be understood, however, that these numbers can be varied to suit any desired speeds at which it is desired to drive the turntable, those speeds here indicated being the ones in most common use today.

The lowermost portion of the spindle bearing 50 as indicated at is provided with detent means adapted to cooperate with a plurality of circumferential grooves on the shift rod 40 corresponding to the diiferent levels at which the idler wheel 6 is to be disposed and at which the various speed indicating numbers 78, 45, 33, and 16 are exposed in view of the operator above the spindle 12.

As best shown in Fig. 5, the detent means associated with the spindle bearing 50 comprises a detent ball 53 disposed within a bore 54 perpendicular to and intersecting the smaller bore 52 of said spindle bearing, said detent ball being radially, inwardly biased by means of a U-shaped wire spring 55. The U-shaped spring 55 is vertically retained upon the smaller portion 50b of the spindle bearing 50 by meansv of a circumferential groove 56 which so disposes the spring 55 that one relatively longer leg 55a thereof presses radially inwardly upon the detent ball 53 to resiliently maintain said ball in abutting relationship with the shift rod 4d. The opposite, relatively shorter leg of the U-shaped spring 55 as indicated at 55b is provided with an inwardly bent hook portion 550 which seats within a small socket 57 diametrically opposite the detent ball 53. By means of said hook portion the U-shaped spring 55 is prevented from rotating about the bearing 50 and is maintained in contact with the detent ball 53.

The herein referred to grooves into which the detent ball 53 is adapted to seat are provided in the rod 40 above the hub 46. The grooves as shown are numbered from the uppermost of said grooves downwardly as 20, 21, 22, 23', said grooves corresponding respec tively to the pulley drive portions 20, 21, 22, and 23 of the rotor shaft 5. It will be understood, therefore, that when the shift rod 40 is in its lowermost position, the speed indicating number 78 is exposed above the spindle 12, the detent ball is seated in the groove 20", and the idler wheel 6 peripherally engages the pulley drive portion 20 of the rotor shaft 5. When the shift rod 40 is manually raised by means of the control knob 45 to the position where the speed indicating number 45 is exposed above the spindle 12, the detent ball 53 engages the groove 21 and the idler wheel 6 is disposed aoeissa at the level of the pulley drive portion 21. When the speed indicating number 33 is exposed, the detent ball engages the groove 22 and the idler wheel is disposed at the level of the pulley drive portion 22, andwhen the speed indicating number 16 is exposed, said detent ball engages the groove 23 and the idler wheel 6 is then disposed at the level of the uppermost, smallest pulley driving portion 23.

It will be noted that the lands between the grooves 20', 21', 22', and 23 vary in diametric dimension and shape. The uppermost land 60 is herein illustrated as being of the same diametric dimension as the normal dimension of the shift rod 40. The land 61 is diametrically smaller than the land 60, and the land 62 is provided with a deeper shoulder portion at the uppermost edge thereof as indicated at 62a than at the lowermost edge thereof, as indicated at 62b. By varying the diametric size of the lands, and more particularly the shoulder portions thereof, it can be readily seen that the detent ball 53 resists being forced out of the various grooves to varying degrees. For example, when the shift rod is moved from the 78 r.p.m. position to the 45 rpm. position, more pressure is required than when said rod is moved from the 45 rpm. position to the 33 rpm. position. However, resistance is again increased when shifting from the 33 rpm. position to the 16 rpm. position due to the fact that the shoulder 62a is sharper than the shoulders of the proceeding land 61. The operator can, therefore, shift the present speed changing mechanism without actually observing the speed indicating numbers simply by noting the different amounts of pull or pressure necessary to move the shift rod 49 in a vertical direction. Obviously, the same advantage is attained when moving the shift rod down wardly as when moving said rod in an upward direction.

As best shown in Fig. 4, the spindle 12 is retained within the spindle bearing 5% by means of a spring clip 58 having a straight leg portion 53a engaging a circutn ferential groove 59 in the lower reduced portion 12a of said spindle. The reduced portion 5%!) is ground away at one point in its circumference, as indicated at 65, to form a flat bottom groove -in which the leg 58a of the spring clip 58 is seated. In this way, the spindle 12 freely rotates within the spindle bearing 50, but is maintained against vertical displacement by means of the spring clip 53; and the shift rod 46 is slidabiy movable within the bore 43 and the socket 42 of the spindle 12 from an extreme lowermost position wherein the detent ball 53 is seated in the groove 20' to an uppermost portion wherein said detent ball is seated in the groove 23.

The present speed changing mechanism reduces the speed changing operation of a phonograph to a simple push-pull mechanism associated with the spindle of a phonograph turntable. The present device is particularly well adapted to small record players, such as those of the portable type wherein space is at a premium. In said portable type phonograph, the location of the control knobs is commonly in a very awkward position adjacent the turntable flange, and said knobs are particularly difficult to reach when a normal size record is on the spindle. The present device provides a manual shift means at the most convenient possible place, the center of the turntable. If the operator inadvertently sets the shift mechanism for the. wrong speed before playing a record, it is not necessary that he stop the machine, remove the record, or remove the tone arm, but it is only necessary that he grasp the control knob and pull the same to indicate the desired speed.

It will be understood that my invention is not limited to the particular drive mechanism shown herein and that the idler wheel mounting and speed transmission means may be of variant forms.

It will be further understood that many departures from the details of my invention as it is herein described and illustrated may be made, such as changes in size and dimension, type of drive, without, however, departing from the spirit of my invention or the scope of the appended claims.

What I claim is:

1. A phonograph turntable speed-changing drive mechanism comprising motor driven driving means adapted to drive a turntable at a plurality of different speeds by a part of said driving means being shifted to different levels, a vertically movable shift rod mounted separately from said driving means, speed indicating means on said shift rod, means interconnecting said shift rod with said part of said driving means which is adapted for movement to different levels, said speed indicating means comprising a plurality of symbols corresponding in number to the different speeds of said driving means, said symbols being successively exposed synchronously with each said speed change and indicating the speed at which said turntable is being driven.

2. A phonograph turntable speed-changing drive mechanism comprising a plurality of motor driven drive pulleys disposed at different levels and adapted to drive a turntable at different speeds, vertically shiftable means interposed between said drive pulleys and said turntable and adapted to contact said drive pulleys and transfer driving motion to said turntable at a speed corresponding to the pulley at the level of which said shiftable means is disposed, a vertically disposed, longitudinally movable shift rod mounted within fixed bearing means, speed indicating means on said shift rod, means interconnecting said shift rod with said shiftable means, said speed indicating means being progressively exposed above said bearing means when said shift rod is moved upwardly and indicating the speed at which said turntable is being driven after each movement of said shiftable means from one of said drive pulleys to another.

3. A plural speed, phonograph turntable driving mechanism adapted to drive a turntable of the type having a circumferentially continuous, depending flange, said mechanism comprising motor driven drive pulleys of different diameters disposed at different levels, an idler Wheel adapted to resiliently, simultaneously engage one of said drive pulleys and said flange, vertically movable mounting means for said idler wheel, a vertically disposed, axially manually movable shift rod mounted separately from said mounting means within fixed bearing means, means interconnecting said shift rod with said mounting means whereby movement of said shift rod moves said idler wheel, speed indicating means disposed longitudinally along said shift rod, said speed indicating means being progressively exposed above said bearing means when said shift rod is moved upwardly and indicating the speed at which said turntable is being driven after each movement of said idler wheel from one of said drive pulleys to another.

4. A plural speed, phonograph turntable driving mechanism adapted to drive a turntable of the type having a circumferentially continuous, depending flange, a turntable spindle, said turntable mounted upon said spindle, a plurality of motor driven drive pulleys of different diameters disposed at different levels, an idler wheel adapted to resiliently simultaneously engage one of said drive pulleys and said flange, vertically movable mounting means for said idler wheel, a vertically disposed, axially manually movable shift rod associated with said spindle, means connecting said shift rod with said mounting means whereby said shift rod is movable to dispose said idler wheel at the different levels of said drive pulleys.

5. A plural speed, phonograph turntable driving mechanism adapted to drive a turntable of the type having a circumferentially continuous depending flange, a hollow spindle for rotatably mounting said turntable, a plurality of motor driven drive pulleys of different diameters disposed at different levels, an idler wheel adapted to resiliently simultaneously engage one of said drive pulleys and said flange, vertically movable mounting means for said idler wheel, a vertically slidable shift rod disposed within said spindle, cantilever means connecting said shift rod to said mounting means whereby said shift rod is movable to dispose said idler wheel at the different levels of said drive pulleys.

6. A plural speed, phonograph turntable driving mechanism adapted to drive a turntable of the type having a circumferentially continuous depending flange, said mechanism unitarily mounted upon a plate and comprising a plurality of motor driven drive pulleys of different diameters disposed at different levels; an idler Wheel rotatably mounted upon a vertically movable mount and adapted to simultaneously engage one of said drive pulleys and said turntable flange to transmit rotary motion therebetween, a hollow spindle for rotatably mounting said turntable, a vertically movable rod disposed within said spindle with the lowermost end of said rod projecting below said plate, a lift cantilever mounted to said lowermost end and projecting upwardly above said plate to engage said movable mount whereby when said rod is vertically moved, said idler wheel is disposed at different levels to contact different of said drive pulleys.

7. A plural speed device as set forth in claim 6 having detent means associated therewith adapted to resistably maintain said idler wheel at each of the levels of the drive pulleys.

8. A plural speed, phonograph turntable driving mechanism adapted to drive a turntable of the type having a circumferentially continuous depending flange, said mechanism comprising a motor driven rotor shaft having drive pulley portions of different diameters adapted to drive said turntable at different speeds and being disposed at different levels, an idler wheel adapted to transfer rotativc motion from one of said drive pulley portions to said turntable flange, a vertically and horizontally movable mount for said idler wheel, a hollow spindle upon which said turntable is rotatably mounted, a manually operated shift rod vertically movable within said spindle and projecting upwardly from said spindle, a cantilever secured to said shift rod at one end of said cantilever and to said movable mount at the other end thereof whereby said idler wheel is disposed at different levels to contact different of said drive pulley portions by movement of said shift rod, detent means associated with said shift rod and adapted to hold said rod in a plurality of vertical positions, speed indicating means associated with said shift rod, said idler wheel, detent means, and said speed indicating means being so related in the movements thereof as to synchronously dispose said idler wheel at the proper drive pulley level corresponding to one of said vertical positions of said detent means when said speed indicating means shows the speed at which said turntable is being driven.

9. A plural speed, phonograph turntable driving mechanism adapted to drive a turntable of the type having a depending, peripheral flange, said mechanism unitarily mounted upon a plate and comprising a stepped, motor driven, rotor shaft having pulley portions of different diameters disposed at different levels, said rotor shaft projecting above said plate, an idler wheel and a vertically and horizontally movable mount for said idler wheel, a hollow spindle rotatably mounted within a spindle hearing, said bearing mounted in said plate and having a portion thereof extending below said plate, a shift rod slidably interfitting said spindle and projecting below said bearing, a detent ball positioned within an aperture in said bearing, spring means biasing said detent ball radially inwardly whereby said ball contacts said shift rod, a plurality of spaced grooves in said shift rod adapted to receive said ball to retain said shift rod in selected vertical positions, a cantilever connected to the lowermost end of said shift rod and extending upwardly above said plate to engage said mount to cause said mount to move vertically with said shift rod whereby said idler wheel is moved to different levels by movement of said shift rod to contact different of said pulley portions to drive said turntable at diflerent speeds.

10. A plural speed, phonograph turntable driving mechanism as set forth in claim 9 wherein the recited shift rod extends upwardly above said spindle, said rod having speed indicating means imprinted thereon whereby the speed at which said turntable is driven is exposed above said spindle in each vertically shifted position of said idler Iwheel.

11. A shiftable mechanism of the type for vertically shifting part of a phonograph drive mechanism to vary the speed of a phonograph turntable, said shifting mechanism comprising a hollow turntable spindle, a bearing for said spindle, a rod member vertically movable within said spindle, said rod member having gripping means projecting above said spindle, detent means mounted in said bearing and adapted to cooperate with means on said rod member to maintain said member in a plurality of vertical positions, a drive mechanism including a vertically shiftable part thereof, said rod member having means associated therewith connected to said vertically shiftable part of said phonograph drive mechanism to cause said part to be shifted to diiferent driving levels, and speed indicating means on said rod member adapted to be exposed to view above said spindle at each of said driving levels.

12. A shifting mechanism of the type for vertically shifting part of a phonograph drive mechanism to vary the speed of a phonograph turntable, said shifting mechanism comprising a hollow turntable spindle, a bearing for said spindle, a rod vertically movable within said spindle, said rod having gripping means projecting above said spindle, a detent ball mounted in said bearing within a horizontal aperture thereof, spring means biasing said ball into contact with said rod, said rod having a plurality of longitudinally spaced grooves adapted to receive said ball, a drive mechanism including a vertically shiftable part thereof, said rod having means associated therewith connected to said shiftable part of said phonograph drive mechanism to cause said part to be shifted to different driving levels, said ball and grooves adapted to maintain said rod in a plurality of vertical positions corresponding to said different driving levels, and speed indicating means on said rod adapted to be exposed to view above said spindle to indicate the corresponding speed at each of said different driving levels.

13. A shifting mechanism as set forth in claim 12 wherein the recited grooves in said rod are provided with shoulder portions of various depths whereby said detent ball provides varying amounts of resistance to the vertical shifting of said rod during the shift to said different driving levels.

14. A detent mechanism comprising longitudinally shiftable control rod, said rod being grooved at longitudinally spaced intervals, said rod mounted within hearing means, a detent ball mounted within a transverse aperture in said bearing means and adapted to abut said rod, said bearing means having a circumferentially grooved, outer periphery the groove of which intersects said aperture, a U-shaped spring seated in said groove, said spring having a pair of leg portions, one of said leg portions being bent inwardly toward said bearing means opposite said detent ball and seated within a complementarily interfitting socket in said bearing means and the other of said leg portions abutting said detent ball to resiliently urge the same into contact with said rod whereby said ball automatically successively engages the grooves in said rod when said rod is moved longitudinally within said bearing means in either direction.

15. A detent mechanism as set forth in claim 14 wherein the recited grooves in said rod are provided with shoulder portions of various depths whereby said detent ball provides varying amounts of resistance to the longitudinal shifting of said rod from a position as determined by one of said grooves to a different position as determined by another of said grooves.

16. A plural speed selecting means for phonograph turntables including a turntable spindle, manually controlled operable means mounted upon said spindle, speed change indicia carried by said manually operable means, a motor, a rotor shaft spaced from the turntable spindle, means driven by said rotor shaft and drivingly engaging the turntable, said manually operable means adapted to diiferently dispose said second mentioned means relative to the turntable and said rotor shaft to drive the phonograph turntable at speeds determined by the selected position of said speed change indicia.

17. A plural speed selecting means for driving a phonograph turntable of the type having a peripheral, depending flange, said turntable mounted upon a spindle, manual control means mounted upon said spindle, a motor, transmission means interposed between said motor and said turntable flange to rotate said turntable, said transmission means shiftable to drive said turntable at a plurality of different speeds, means connecting said manual control means to said transmission means whereby said transmission means is shifted by said manual control means to drive said turntable at different speeds.

18. A plural speed drive for rotatatively driving a vertically stationary phonograph turntable mounted upon a hollow spindle and comprising a motor, transmission means driven by said motor and adapted to engage said turntable to drive the same, said transmission means shiftable to drive said turntable at a plurality of different speeds, and manual control means projecting through said spindle and adapted to shift said transmission means to drive said turntable at difierent speeds.

19. A plural speed drive as set forth in claim 18 wherein the recited manual control means carries speed change indicia adapted to indicate the speed at which said turntable is being driven.

20. A plural speed drive for rotatively driving a phonograph turntable mounted upon a hollow spindle and comprising a motor, transmission means shiftable to drive said turntable at different speeds interposed between said motor and said turntable, manual control means projecting through said spindle above and below said tumtable, means connecting said manual control means below said turntable to said transmission means whereby said manual control means shifts said transmission means to drive said turntable at different speeds.

21. A plural speed turntable driving mechanism comprising a spindle, a turntable mounted on said spindle, said spindle being longitudinally apertured, a control rod movably positioned in said aperture, a motor, plural speed transmission means associated with said motor and said turntable having parts thereof shiftable to different interrelated positions to drive said turntable at different speeds and responsive to movement of said control rod, said control rod having a grip portion extending beyond said spindle for manual actuation of said control rod, and said grip portion having indicia imprinted thereon adapted to indicate the speed of said turntable.

References Cited in the file of this patent UNITED STATES PATENTS 2,134,756 Gerry Nov. 1, 1938 2,254,066 Gruber et al. Aug. 26, 1941 2,260,289 Brady et al. Oct. 28, 1941 2,260,319 Hoehn Oct. 28, 1941 2,502,639 Blake Apr. 4, 1950 FOREIGN PATENTS 1,091,862 France Nov. 3, 1954

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