US3833225A

US3833225A - Driving mechanism for the turntable in record players

Info

Publication number: US3833225A
Application number: US00291525A
Authority: US
Inventors: K Pettersson; G Logue
Original assignee: Industriaktiebolaget Luxor
Current assignee: Industriaktiebolaget Luxor
Priority date: 1971-09-27
Filing date: 1972-09-25
Publication date: 1974-09-03
Anticipated expiration: 1991-09-03
Also published as: SE353615B; DE2246949B2; DE2246949C3; DE2246949A1; GB1376670A

Abstract

A driving mechanism for the turntable in record players having a reversible motor is provided in which reversal of the direction of rotation of the motor automatically changes the speed of rotation of the turntable.

Description

United States Patent [1 1 [111 3,833,225

Pettersson Sept. 3, 1974 DRIVING MECHANISM FOR THE [56] References Cited TURNTABLE IN RECORD PLAYERS UNITED STATES PATENTS [75] Inventor: Karl Albin Bertil Pettersson, 2,563,649 8/1951 Hartman 274/9 A Motala Swede FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Luxor Industri Aktiebolag, Motala, 1,425,761 2/1965 France 274/39 R Sweden 766,560 l/l 957 Great Britain 274/9 A [22] Bled: sept' 1972 Primary ExaminerHarry N. Haroian [21] Appl. No.: 291,525 Attorney, Agent, or FirmYoung and Thompson 30 Foreign Application Priority Data [57] ABSTRACT S A driving mechanism for the turntable in record playept. 27, 1971 Sweden 12154/71 ers having a reversible motor is provided in which reversal of the direction of rotation of the motor autog 274/9 matically changes the speed of rotation of the tumtable Field of Search 274/9, 39

3 Claims, 4 Drawing Figures mmnnsm i974 $833225 SHEET 3 BF 3 Fig. 4

DRIVING MECHANISM FOR THE TURNTABLE IN RECORD PLAYERS The present invention relates to a driving mechanism in record'players for driving the turntable with two different speeds.

The French specification No. l 425 761 discloses a record player in which the turntable on its bottom side has two concentric flanges between which a driving wheel driven by a motor may be moved into engagement with one or the other of said flanges.

In this known device the setting of the desired speed of the turntable is effected by means of a manually operated control member which 'actuates the said driving wheel to move it ,into one or the other driveengagement position in a purely mechanical way at the same time as the motor is given a reversed direction of rotation by means of an electrical reversing switch. As the control member has to be mechanically connected with the driving wheel, or partsassociatedtherewith, difficultiesmay arise in locating the control member where this would be desirable for other reasons. If the actuationcould be effected in a purely electrical way, the control member could be located practically anywhere.

According to the present invention this problem is solved by causing the rotation of the motor to produce torques which result in the setting of the position of the driving wheel.

More particularly, the record player according to the invention comprises a base plate, a shaft carried by said base plate, a turntable mounted on said shaft, a reversible motor carried by said baseplate, the turntable, or a disc drivingly connected therewith, being provided with an outer circular flange and with an inner circular flange between which a driving wheel adapted to be driven by the said motor and forming a driving unit therewith is movable into engagement by its periphery with either the outer flange positioned radially outside the driving wheel, or with the inner flange positioned radially inside the driving wheel so as thereby to cause rotation of the turntable always in the same direction by selecting opposite direction of rotation of the motor depending upon whether the driving wheel is in engage- .ment with the outer or with the inner of said flanges,

the driving wheel being mounted rotatable in a support means which is provided about a pivot axis which is separate from the axis of rotation of the driving wheel, a braking means adapted to brake a part pertaining to said driving unit and rotating at the rotation of the motor, in order to turn said support means about its pivot axis through a torque arising as a reaction of said braking, so that the driving wheel is moved into engagement with one of said flanges when the motor rotates in a first direction, and with the other of said flanges when the motor rotates in the opposite direction.

The invention will be described in the following in connection with the accompanying drawings in which:

FIG. 1 illustrates a record player provided with the device of the invention, as seen from the top;

FIG. 2 represents an electrical circuit for the motor of the same record player;

FIG. 3 illustrates, at an enlarged scale, a detail of the driving device,'and

FIG. 4 illustrates, also at an enlarged scale, a corresponding detail of a modification of the driving device.

In the drawing, 1 is the base plate of the record player, 2 its pickup arm and 3 its turntable which is rotatably mounted about a vertical shaft 4. The bottom side of the turntable 3 is provided with a pair of depending

circular flanges

5 and 6.

At the side of the turntable there is mounted, adjacent and under the base plate 1, through three elastic bushings 7, a motor plate 8 in which a motor 9 is resiliently suspended (the springs 10). The driving shaft of the motor is provided with a pulley 11 which via a belt 12 is drivingly associated with another pulley 13 fixedly connected with a driving wheel 14 for alternative driving engagementwith the

flanges

5 and 6.

How the pulley l3 and the driving wheel 14 are arranged is best seen from FIG. 3. These two members are rotatable about a vertical shaft 15, which in turn is rotatably mounted in a bracket 16. This is pivotally mounted about a vertical shaft 17 secured in the base plate 1.

The shaft 15 has secured to it, under the pulley 13, a friction disc 18 as well as, under the latter, a small gear 19 which is in mesh with a large gear 20 rotatable about a shaft 21 provided in the bracket. Under the pulley 13 there are fixed to it a pair of

pins

22 and 23 in which there are fixed blade springs 24 which with the interpositioning of friction felt 25 embrace the friction disc 18.

For blocking the gear 20 there is a latch'26 (see FIG. 1) pivotally mounted in the motor plate 8. This latch is coupled in a way not shown to the pickup arm 2 of the record player, so that, when the pickup arm is resting on its support, the latch 26 is moved in the direction of the arrow 27, wherebythe device shown in FIG. 3 is free to move to such extent-as is allowed by the play between the driving wheel 14 and the flanges 5 and 6.-

Thereby the contact pressure between the wheel and the flanges is reduced and indentations in the driving path of the wheel are avoided.

The motor 9 is preferably of a self-starting synchronous type. In FIG. 2 the electrical arrangement of the motor is shown. The mains voltage is applied between the

terminals

28 and 29. The switch of the motor is designated by 30, the motor windings by 31 and 32 and a condenser by 33. The motor is reversed by means of a reversing switch 34.

In FIG. lthe pickup arm 2 is shown in a raised position and the switch 34, which according to the invention may be located at any suitable place on the record player, is set in such a position that the motor 9 with the pulley 11 will rotate clockwise. The latch 26 is in engagement with the gear 20, whereby the shaft 15 is blocked against rotation via the gear 19. At the clockwise rotation of the motor 9 the left-hand part of the belt 12 will be the pulled one. By the belt tension there, which is further increased by the fact that the driving wheel 14 and the pulley 13 must rotate against the action of the fricton means 24, 25 and 18, the driving wheel device according to FIG. 3 will be turned to the left about the shaft 17 and the driving wheel 14 brought into engagement with the outer flange 5 of the tumtable 3, driving the latter at a lower speed, e.g. 33 r/min. Obviously, due to the cooperation of the small gear 19 and the large gear 20, blocked by the latch 26, a greater torque will act upon the bracket 16 than that which directly corresponds to the torque arising at the braking.

When reversing the direction of the motor the righthand part of the belt 12 will be the pulled one. By the belt tension there, increased in the same way as before, the driving wheel device according to FIG. 3 will turn counter-clockwise about the shaft 17, bringing the driving wheel 14 into engagement with the inner flange 6 of the turntable 3, driving the latter at a higher speed, eg 45 r/min.

A modification of the driving wheel device according to FIG. 3 is shown in FIG. 4. There the driving wheel 14 and the pulley 13 are rotatable about a stationary shaft 35. Between the latter and the pulley 13 there is, in the same way as described above, provided the friction means 18, 25 and 24. The shaft 35 is secured in an inner bracket 36, which is pivoted around

pins

37 and 38 within an outer, stationary bracket 39. The

pins

37 and 38 are eccentrically mounted in relation to the shaft 35 and are situatedslightly nearer the motor 9 than said shaft and substantially in a vertical plane passing through the shaft 35 andthe shaft of the motor 9. In reversing the direction of rotation of the motor the driving wheel unit will turn about the

pins

37 and 38 to bring the driving wheel 14 into alternative engagement with the flanges and 6.

According to a further modification one may mount the driving wheel 14, according to the embodiment first described, directly on the motor shaft and have the motor pivoted about an axis eccentrically arranged in relation to the motor shaft, the parts 18-26 being used as braking means. The

pins

22 and 23 are then mounted directly on the bottom side of the driving wheel 14. 7

Clearly, it may be conceived to increase the bearing friction of the driving wheel 14 by other means sufficiently for the braking action to become such that a positive swinging of the driving wheel when reversing the direction of rotation of the motor and a suitable contact pressure against the

flange

5 or 6, respectively, will be guaranteed. In estimating the contact pressure the self-locking due to the driving operation must also be taken into consideration.

As the reversing switch according to the invention is connected only electrically with the motor, the former may be placed anywhere on the base plate. In the case of the belt drive according to the first two examples described the motor has only one pulley so that the belt tension will be constant at both speeds and the life of the belt longer.

What I claim is:

l. A record player comprising a base plate, a shaft carried by said base plate, a turntable mounted on said shaft, a reversible electric driving motor carried by said base plate, a reversing switch for said motor, an outer circular flange and an inner coaxial circular flange drivingly connected with said turntable, a driving wheel driven by said motor and disposed between said outer and said inner flange and forming a driving unit with said motor and movable into engagement at its periphery with either the outer flange or the inner flange for causing rotation of the turntable always in the same direction of rotation but with different speeds by giving said motor and said driving wheel a first direction of rotation for cooperation with said outer flange when said switch in a first position and an opposite direction of rotation for cooperation with said inner flange when said switch in a second position, said driving wheel being mounted for rotation in a support means pivotable about a pivot axis spaced from the axis of rotation of said driving wheel, braking means rotating together with said driving wheel and frictionally cooperating with means fast with a small gear having the same axis of rotation as said driving wheel, a larger gear rotatable in a bearing on said support means with an axis of rotation spaced from said axis of rotation of said small gear, and a latch carried by said base plate and engageable in a tooth gap on said larger gear to block said larger gear thereby pivoting said support means to bring said driving wheel to engage said outer flange or said inner flange in dependence on the direction of rotation of said motor and said driving wheel.

2. A record player as claimed in claim 1, in which said braking means comprise friction elements fast with said driving wheel and said means fast with said small gear include a friction disc coaxial with said driving wheel.

3. A record player as claimed in claim 1, and a driving belt driven by said motor and acting on a pulley fast with said driving wheel, said motor being positioned in relation to said support means to produce by the higher belt tension in the tensioned part of said belt a torque acting on said support means in the same direction as the torque produced by said braking means.

Claims

1. A record player comprising a base plate, a shaft carried by said base plate, a turntable mounted on said shaft, a reversible electric driving motor carried by said base plate, a reversing switch for said motor, an outer circular flange and an inner coaxial circular flange drivingly connected with said turntable, a driving wheel driven by said motor and disposed between said outer and said inner flange and forming a driving unit with said motor and movable into engagement at its periphery with either the outer flange or the inner flange for causing rotation of the turntable always in the same direction of rotation but with different speeds by giving said motor and said driving wheel a first direction of rotation for cooperation with said outer flange when said switch in a first position and an opposite direction of rotation for cooperation with said inner flange when said switch in a second position, said driving wheel being mounted for rotation in a support means pivotable about a pivot axis spaced from the axis of rotation of said driving wheel, braking means rotating together with said driving wheel and frictionally cooperating with means fast with a small gear having the same axis of rotation as said driving wheel, a larger gear rotatable in a bearing on said support means with an axis of rotation spaced from said axis of rotation of said small gear, and a latch carried by said base plate and engageable in a tooth gap on said larger gear to block said larger gear thereby pivoting said support means to bring said driving wheel to engage said outer flange or said inner flange in dependence on the direction of rotation of said motor and said driving wheel.