US3838859A

US3838859A - Speed shift for a phonograph player drive

Info

Publication number: US3838859A
Application number: US00363579A
Authority: US
Inventors: M Estkowski
Original assignee: VM Corp
Current assignee: VM Corp
Priority date: 1973-05-24
Filing date: 1973-05-24
Publication date: 1974-10-01
Anticipated expiration: 1991-10-01

Abstract

The invention provides a drive with speed shift suitable for driving a phonograph turntable for playing records at different speeds, selectively, such as 33 rpm records at one setting of the drive and 45 rpm records at another one setting of the drive. It comprises a belt drive utilizing an elastic belt of polygonal (square) cross section forming the connection between a drive shaft pulley carrying two or more adjacent V-grooves and a driven cylindrical drum. The pulley with the V-grooves is mounted on a shaft which is disposed parallel to the axis of the drum. The Vgrooves are of the same angle of groove, but of different diameters and each cooperates through the belt with the drum to provide two or more selectable turntable speeds by means of a fork shifter for shifting of the belt from one V-groove to another, or the other V-groove, while the belt aligns itself in a plane normal to the axis of the drum. The belt is square in cross section. It racks on two of its adjacent sides in the V-grooves but on one side only of the drum. The driving pulley has two adjacent V-grooves with a ridge between them, which ridge has two spaced apart diagonal grooves inclined in opposite directions for assisting the shifting of the belt from one groove to the other and vice versa for selecting the drive ratio appropriate for the speed of the record on the turntable. The drive ratio is changeable by raising or lowering an axially movable speed selecting rod shift which extends axially a short distance above the center of the turntable. This makes possible a player simple in construction, convenient and reliable in operation and excellent in performance. The complete player mechanism including the turntable with its connected motor drive belt transmission and speed shift, comprises a unitary operative assembly suitable to be mounted on a supporting base board, without elaborate housing.

Description

United States Patent [191 Estkowski 1 SPEED SHIFT FOR A PHONOGRAPH PLAYER DRIVE [75] Inventor: Michael H. Estkowski, St. Joseph,

Mich.

[73] Assignee: V-M Corporation, Benton Harbor,

Mich.

[22] Filed: May 24, 1973 21 Appl. No.: 363,579

[52] US. Cl 274/9 A [51] Int. Cl. Gllb 3/00 [58] Field of Search 274/39 R, 39 A, 9 A, l E;

[56] References Cited UNITED STATES PATENTS 1,471,726 10/1926 Ginty 74/242.4 2,051,819 8/1936 Carson 274/9 A Primary ExaminerHarry N. Haroian Assistant Examiner-John W. Shepperd Attorney, Agent, or Firm-Johnson, Dienner, Emrich, Verbeck & Wagner [57] ABSTRACT The invention provides a drive with speed shift suit- [4 Oct. 1,1974

able for driving a phonograph turntable for playing records at different speeds, selectively, such as 33 rpm records at one setting of the drive and 45 rpm records at another one setting of the drive. It comprises a belt drive utilizing an elastic belt of polygonal (square) cross section forming the connection between a drive shaft pulley carrying two or more adjacent V-grooves and a driven cylindrical drum. The pulley with the V- grooves is mounted on a shaft which is disposed parallel to the axis of the drum. The V-grooves are of the same angle of groove, but of different diameters and each cooperates through the belt with the drum to provide two or more selectable turntable speeds by means of a fork shifter for shifting of the belt from one V-groove to another, or the other V-groove, while the belt aligns itself in a plane normal to the axis of the drum. The belt is square in cross section. It racks on two of its adjacent sides in the V-grooves but on one side only of the drum. The driving pulley has two adjacent V-grooves with a ridge between them, which ridge has two spaced apart diagonal grooves inclined in opposite directions for assisting the shifting of the belt from one groove to the other and vice versa for selecting the drive ratio appropriate for the speed of the record on the turntable. The drive ratio is change able by raising or lowering an axially movable speed selecting rod shift which extends axially a short distance above the center of the turntable. This makes possible a player simple in construction, convenient and reliable in operation and excellent in performance. The complete player mechanism including the turntable with its connected motor drive belt transmission and speed shift, comprises a unitary operative as sembly suitable to be mounted on a supporting base board, without elaborate housing.

1 Claim, 4 Drawing Figures k l I: gZiZT'IIILI: Z; 3 16 SPEED SHIFT FOR A PI-IONOGRAPH PLAYER DRIVE BACKGROUND OF THE INVENTION to satisfy the demand for a player suitable for youthful PRIOR ART The prior art of record players has failed to furnish a simple, rugged, low-cost construction such as the present invention makes possible.

OBJECTS OF THE INVENTION The primary object of the invention is to provide a rugged, high quality performance record player of simple and reliable construction at a cost low enough to allow the player of this invention to be put into the hands of children.

An incidental object is to provide a novel drive with greatly simplified and easily understood and operated speed selector for phonographs and the like.

The preferred form of the drive involves two rotatable members with their axes parallel. One is a drive shaft; the other is a driven drum. The drive shaft mounts a pulley having two V-grooves of different diameters side-by-side on the same axis, and a driven cylindrical drum member presenting the same diameter to each of the V-grooves of the pulleys and being on an axis parallel to the axis of said pulleys. The profile of each groove is substantially rectangular for maximum effective area of engagement between the two adjacent sides of the belt and the V-grooves of the pulley.

A single belt, of rectangular cross section, sufficiently elastic to operate on the drum and the larger diameter V-pulley, and of sufficient tension and friction grip to provide a satisfactory drive is trained over the drum and either of the V-grooves of the pulley. The drive ratios taking into account the appropriate synchronous speed of the driving electric motor provide rotation of the drum and turntable at 33 rpm when the drive is through the smaller diameter pulley, and 45 rpm of the drum and turntable when the drive is through the pulley of larger diameter.

A desirable feature of the present invention allows the shifter fork, or equivalent, to be moved from one speed position to another speed position with a full stroke spring throw while the drive is in operation, and the drive belt will find its corresponding position according to the setting of the shifter fork. This is preferably aided by one or more diagonal cuts or transfer grooves in the ridge between grooves on the pulley whereby the belt will move into the selected drive ratio for playing the corresponding record at, for example, 33 rpm or 45 rpm, according to the setting of the shifter fork. An indication of the speed at which the selector is set may be registered on the shifter member, which member preferably extends up through the central axis of the drum and the attached plate.

The pulley is provided with a diagonal shift groove on one side of the pulley for assisting transfer from 33 to 45 rpm and with an appropriate diagonal shift groove preferably on the opposite side of the pulley for assisting in transfer from 45 to 33 rpm drive.

Thus the annular ridge dividing the two grooves may bear a diagonal cut to assist the belt to be transferred from the low speed to the high speed groove and a similar diagonal cut in the opposite direction may be dis posed in the dividing ridge between the two grooves for shifting the belt in the opposite direction.

The significance of the joint operation of the full stroke mechanism produced by the over center spring 29 connected to the shifter fork and the diagonal shifting grooves 26-26 lies in the fact that they, in combination with the moving belt, constitute a power driven shift of the drive ratio. The full stroke snap action spring 29 throws the fork 9 which carries the run of the belt embraced by the fork laterally all the way endwise of the pulley to its new final driving position, and the moving pulley brings the diagonal transfer groove 26 with its leading end into registration with the part of the belt which has been moved to the shifted position-that is, in registration with the receiving groove 16 or ]l3-with the result that the belt is thrown into the transfer groove and thence into the desired

full circle groove

16 or 17. Thus, with minimum effort, the run of the belt from one groove to the other is accomplished with rapidity and certainty, and minimum wear on the belt.

DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view of the turntable as though viewed from the top of FIG. 2 with the margins of the turntable broken away;

FIG. 2 is a vertical longitudinal section taken on the line 22 of FIG. 1 showing the drive in high speed position;

FIG. 3 is a view similar to FIG. 2 except that the speed selector and connected parts has been shifted to the low speed drive; and

FIG. 4 is a side elevational view of the pulley with two V-grooves for the corresponding speeds of drive and showing also one of the spiral grooves to assist the driving belt in climbing out of one groove over into the other when the shifter fork is set accordingly.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 2 and 3 show the supporting base 1 which may be part of a cabinet or container. A through opening 2 permits parts of the mechanism to extend below the support 1. Over the opening 2 there is disposed a frame plate 3 upon which the moving parts, hereinafter described, are mounted. The frame plate 3 supports two main items--namely, the motor with its connected parts 4 and the hollow axle 5 which is set into and staked, or otherwise secured, to the frame plate 3. This hollow axle 5 provides a central bore through which extends the manual shifter rod 6. The rod 6, which may bear indications of its position, is slidable in the said sleeve 5 and carries at its lower end the hub 7 of bracket member 8. This bracket member 8 carries on its outer end a shifter fork 9 which contains ashifter slot 10 with upper and

lower fingers

11 and 12 between which is disposed, at all times, the belt 13. The belt 13 is preferably an elastic endless band (of square cross section) which embraces the pulley 14 carried on the motor drive shaft 15 and fixed thereto. The pulley l4 has two V-grooves l6 and 17. The groove 16 at the upper end of the motor shaft is of a diameter such that when the belt 13 is in the groove 16 and trained around the drum 18, the drum l8 and the connected turntable 19 will rotate at 33 rpm for a given synchronous speed of the motor 4. When the belt 13 is shifted to the groove 16 of the upper part of the drive, the belt 13 remains on the same diameter of the drum 18, which is a plain cylinder, and the drive turntable 19 will be at 45 rpm.

The turntable 19 has at its outer periphery a cylindrical wall 20 extending above and below the central horizontal disc 21 which disc carries on its lower face a cylindrical flouge which forms the large diameter pulley 18 with which the belt 13 cooperates. The central part of the disc 21 has a hub portion 22 in which there is mounted a bearing sleeve 23 to form an antifriction journal with the post 5, which post 5 is fixed at its lower end in the frame plate 3.

The upper end of the post 5 carries a groove in which a hairpin spring 24 is engaged and the function of which is to cooperate with the washer 25 to avoid accidental raising of the turntable 19 relative to the post 5.

The depending rim of the cylindrical wall 20 encloses the drive parts, as will be apparent from FIGS. 2 and 3.

The shifting of the belt 13 axially of the drum 18 is accomplished by pulling up on the pin 6 from its position shown in FIG. 3 to raise it to the position shown in FIG. 2 whereby the

forks

11 and 12 may pull up on the belt 13 when the same is in the position shown in FIG. 2; or by downward motion of the operating pin 6, depress the belt in the upper groove 16 as shown in FIG. 2 to cause the same to cross over the intervening annular ridge between the two grooves as by way of a diagonal groove 26 cut in the ridge 27 dividing the two

grooves

16 and 17. The annular position of the operating pin 6 and its attached bracket 8 is maintained by a projection 28 formed integral with the body of the bracket or arm 8 and extending up through a slot in the frame plate 3. This arm 28 bears a finger at its upper end to limit downward travel of the bracket 8 and connected parts. An over center biasing spring 29 will hold the bracket 8 yieldingly in either extreme up or extreme down position to facilitate the shifting of the belt from one V-groove to the other V-groove, and to hold it there,

It is to be observed that a groove similar to the groove 26 shown in FIG. 4, on the side of the pulley 14 facing the reader, there is a duplicate groove on the opposite side which is in register with the groove 26 and which, being on the side opposite the groove 26, will shift the belt in the direction opposite to that which the groove 26 of FIG. 4 will shift the belt.

In the operation of the device, as a substitute for the bracket arm 8 mounted on the lower end of the operating pin 6 and moved by bodily shifting the same, a first class lever may be substituted to provide means for shifting the belt 13. The shifting pin 6 is preferably provided with indicia (not shown) indicating the position of the parts in respect of the rotational speed for which the mechanism is set. The upper surface of the turntable 19 has a central annular flange 33 of a size to enter and fill the hole at the center of a record adapted for rotational speed of 45 rpm.

In operation, the electric motor is energized to drive the turntable at the appropriate speed for the record to be played. The central annular flange 33 is of a diameter to enter the central hole of the 45 rpm records. The position of the 45 rpm records, in an up and down direction, is maintained by the raised ring or flange 35, the belt being at that time disposed in the groove of larger diameter.

For records adapted to be operated at 33 rpm, the central hole is threaded over the operating pin 6 to center the same and the outer rim of the record rests upon the flange 36.

The specific speeds and sizes may, of course, be anything which the playing of a specific record demands. Preferably, suitable indicia will be applied to the operating pin 6 to indicate the speed for which the mechanism is set.

The operation of the device is apparent from the foregoing description of the structure. The motor is energized; the appropriate record is mounted on the turntable; and the tone arm with pick up of usual or any desirable construction is then applied to the groove of the record on the turntable. Suitable mechanism for stopping the rotation when the record has been played, of any suitable character, may be utilized.

The present invention is specifically related to the construction and operation of the speed control of the turntable drive and is not concerned directly with the pick up equipment.

I claim:

1. In combination, a supporting base plate (3) adapted to be disposed horizontally, a stationary bearing sleeve (5) mounted on and extending vertically above the base plate (3) and opening through and below the base plate, a turntable (19) having an upper record supporting face (21) and a downwardly extending central hub (22, 23) said turntable embracing and being rotatably mounted on said bearing sleeve (5), a cylindrical driving drum (18) mounted on the lower side of the turntable (19), a vertical motor drive shaft (15) rotatably mounted on said base plate (3) within the lateral confines of the outer edge of the turntable and the drum (18), a pulley (14) on said shaft (15) in horizontal register with the drum (18), said pulley (14) having two contiguous parallel V-grooves (l6, 17) of different diameters, an elastic belt (13) of substantially square cross section adapted to embrace the drivingdrum with a flat side of the belt and one or the other of said V-grooves with two contiguous sides of the belt, a normally stationary shifter fork (9) embracing the belt (13) and being mounted on the base for transverse movement relative to the belt to shift the belt from one V-groove to the other, a over center snap action spring connected between the fork and the base plate governing the stationary positions and movements of the fork, and a plunger rod (6) slidably disposed in said bearing sleeve (5) and having its upper end disposed above the plane of the record supporting face (21) of the tumtable whereby said rod (6) can be raised or depressed by the fingers of the operator, said plunger rod (6) being connected at its lower end to the fork (9) to provide said transverse movement.

Claims

1. In combination, a supporting base plate (3) adapted to be disposed horizontally, a stationary bearing sleeve (5) mounted on and extending vertically above the base plate (3) and opening through and below the base plate, a turntable (19) having an upper record supporting face (21) and a downwardly extending central hub (22, 23) said turntable embracing and being rotatably mounted on said bearing sleeve (5), a cylindrical driving drum (18) mounted on the lower side of the turntable (19), a vertical motor drive shaft (15) rotatably mounted on said base plate (3) within the lateral confines of the outer edge of the turntable and the drum (18), a pulley (14) on said shaft (15) in horizontal register with the drum (18), said pulley (14) having two contiguous parallel V-grooves (16, 17) of different diameters, an elastic belt (13) of substantially square cross section adapted to embrace the driving drum with a flat side of the belt and one or the other of said V-grooves with two contiguous sides of the belt, a normally stationary shifter fork (9) embracing the belt (13) and being mounted on the base for transverse movement relative to the belt to shift the belt from one V-groove to the other, a over center snap action spring connected between the fork and the base plate governing the stationary positions and movements of the fork, and a plunger rod (6) slidably disposed in said bearing sleeve (5) and having its upper end disposed above the plane of the record supporting face (21) of the turntable whereby said rod (6) can be raised or depressed by the fingers of the operator, said plunger rod (6) being connected at its lower end to the fork (9) to provide said transverse movement.