US3648384A

US3648384A - Turntable drive release mechanism

Info

Publication number: US3648384A
Application number: US26380A
Authority: US
Inventors: Richard W Roberts
Original assignee: Borg Warner Corp
Current assignee: PRESCRIPTION LEARNING Corp 2860 OLD ROCHESTER ROAD PO BOX 2377 SPRINGFIELD ILLINOIS 62705; Borg Warner Corp
Priority date: 1970-04-07
Filing date: 1970-04-07
Publication date: 1972-03-14
Anticipated expiration: 1989-03-14
Also published as: GB1309623A; CA942494A

Abstract

A turntable drive release mechanism for an audiovisual educational apparatus of the type disclosed in U.S. Pat. No. 3,483,633 is disclosed employing a continuously driven friction drive wheel which is moved out of engagement with a turntable in response to an indexing lever carried on and moving with the turntable. The lever engages a releasable stop shaft and pivots to bear against a bellcrank which, through a link, moves the drive wheel away from the turntable while maintaining its contact with the drive motor. Upon release by the stop shaft the drive is returned to engagement by a spring and rotates the turntable one revolution until the indexing lever again contacts the bellcrank and stop shaft, thus returning the turntable to the ''''home'''' position.

Description

United States Patent Roberts [54] TURNTABLE DRIVE RELEASE MECHANISM [72] lnventor: Richard W. Roberts, Lombard, Ill.

[73] Assignee: Borg-Warner Corporation, Chicago, 111.

[22] Filed: Apr. 7, 1970 [21] Appl. No.: 26,380

[ 1 Mar. M, 1972 Primary Examiner-Wm. H. Grieb Attorney--Donald W. Banner, William S. McCurry and John W. Butcher [5 7] ABSTRACT A turntable drive release mechanism for an audiovisual educational apparatus of the type disclosed in US. Pat. No. 3,483,633 is disclosed employing a continuously driven fric tion drive wheel which is moved out of engagement with a turntable in response to an indexing lever carried on and moving with the turntable. The lever engages a releasable stop shaft and pivots to bear against a bellcrank which, through a link, moves the drive wheel away from the turntable while maintaining its contact with the drive motor. Upon release by the stop shaft the drive is returned to engagement by a spring and rotates the turntable one revolution until the indexing lever again contacts the bellcrank and stop shaft, thus returning the turntable to the home position.

6 Claims, 2 Drawing Figures PAIENTEBMAR 14 m2 3 648 3&4

PROGRAM 67 ADVANCE F 2 MECHANISM INVENTOR.

ATTORNE V TURNTABLE DRIVE RELEASE MECHANISM FIELD OF THE INVENTION The present invention relates to audiovisual educational apparatus and particularly to a turntable drive release mechanism for use in such apparatus of the type disclosed in U.S. Pat. No. 3,483,633.

BACKGROUND OF THE INVENTION The present invention is an improvement in audiovisual education apparatus of the type disclosed and claimed in [1.5. Pat. No. 3,483,633, Audiovisual Educational Apparatus which patent issued on Dec. 16, 1969 in the names of Alfred E. Geils, William J. Raymond, Richard W. Roberts (the inventor of the present invention) and Peter K. Shreck, and is assigned to the assignee of the present invention.

SUMMARY OF THE INVENTION In accordance with the present invention an improvement in an audiovisual educational apparatus of the type employing a turntable which must, in operation, be rotated one revolution and returned to and stopped at a home position or orientation comprises a means for disengaging a drive for the turntable (such as a movable friction drive wheel), means carried by or in part, at least, associated with the turntable for indexing it in its home position, and for activating the drive disengaging means whereby the drive means may be disengaged when the turntable assumes its home position and re-engages.

BRIEF DESCRIPTION OF THE DRAWINGS The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with the further advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:

FIG. I is a plan view with parts removed to show interior parts and a moved position shown in phantom lines of an audiovisual apparatus and especially of the turntable drive and stop portions thereof, constructed in accordance with the present invention; and

FIG. 2 is an elevational view of the apparatus of FIG. 1 substantially as seen along the line II-II in that Figure but with some parts shown in block form and other parts shown in a moved position.

DETAILED DESCRIPTION Referring to FIG. 1 there is depicted an audiovisual machine, generally indicated by the numeral 10, of the type disclosed and claimed in the aforementioned Geils, et al. patent. The machine is identical to the machine disclosed in that patent and that disclosure, except for the parts de picted in FIGS. 1 and 2, and the description and drawings of that patent, except for these parts, is incorporated by reference as are fully set out herein (859 0.6. 346).

In accordance with the present invention the machine 10 in cludes an improved means C for driving the turntable and a modified stop mechanism R. The stop mechanism R includes a stop shaft 92a (FIG. 2). In the home position the stop shaft 920 makes contact with a tab 93 which extends vertically from a generally planar lever 200 which is pivotally affixed at 201 to the bottom surface of the turntable P. The lever 200 rotates with the turntable P. The lever 200 lies and pivots in a plane approximately parallel with the horizontal record receiving surface of the turntable P and is also secured thereto by means of a guide 202 which passes through a movement limiting guide slot 203. The guide 202 preferably includes a washer 204 affixed to the guide stud below the bottom surface of the lever 200 which is of sufficient size to support the lever 200 and has sufficient clearance from the bottom of the turntable P so as to allow the lever to slide and pivot in the horizontal plane.

The pivoted lever 200 further includes a depending curving second tab 205. The tab 205 depends so as to be able to make contact with and move an upstanding cured surface defined tab 206 which is part of a bellcrank 207. The tab 206 is at one end of the bellcrank 207 which is pivotally attached to the stationary platform 43 at an intermediate position 200 between its ends. The bellcrank 207, pivots in a horizontal plane. At the other extreme end of the bellcrank is a stop arm 209 which may make contact with a stop post 210.

Intermediate between the pivot 208 and the arm 209 of the bellcrank 207 is a second pivot 21 ll. This pivot 211 connects a link arm 212 which extends and may pivot horizontally. At the extreme end of the link 212, away from the pivot 211, the link 212 is formed into a sleeve bearing 213 for receiving a freely rotating vertically disposed axle 214. Affixed at the upper end of the axle 214 over the upper surface of the bearing sleeve 213 is a horizontally disposed turntable drive wheel 21S having a rubber outer rim 216. During the rotating of the turntable I, this drive wheel 215 makes frictional contact with the inner vertical surface of the depending circular flange 89 of turntable P.

Afflxed to the lower end of the axle 214 below the bottom of the bearing sleeve 213 is a horizontally disposed driven wheel 217 which also preferably has a rubber rim 218. Both of the

wheels

215 and 217 are affixed to the axle 214 so that they turn together.

The driven wheel 217 at all times, has its rim held in frictional contact against the drive shaft 220 of an electric synchronous motor 87. The wheel 217 is urged against the drive shaft 220 by a spiral spring 222 which is affixed at one end to an upstanding tab 224 of the record player platform 43 and at its other end to a tab extension 226 of the axle carrying bearing 213 to lie in a generally horizontal position and provide means for biasing the driven wheel 217 against the drive shaft and also for biasing the drive wheel 215 against the turntable flange 89.

The synchronous motor 87 preferably is run at a fairly high speed, e.g., 3,600 rpm, and the larger diameter driven wheel 217 and drive wheel 215 are so related to one another and the diameter of the flange 89 that the turntable may revolve at a much lower speed of, e.g., [3 rpm.

The stop 92a together with the surface tab 206 of the bellcrank 207 and the lever 200 including its tabs 92a and 20S comprise means for indexing the turntable in its home posi tion. The bellcrank 207, and link arm 212 comprise means for disengaging the drive means including the drive wheel 215 from the turntable P.

OPERATION The operation and function of the above described turntable drive release mechanism can be best understood by reference to FIG. 1 where a moved position of the various parts is shown in phantom lines.

The solid lines of FIG. 1 depict the arrangement of the parts shortly after the institution of a new playing of the record. In this orientation the drive wheel 215 (which is always turning in response to the motor drive shaft 220 driving of the largerdiameter driven wheel 217) is in contact with the flange 89. As the stop shaft 92a is removed from the tab 93' the drive wheel 213 will turn the turntable from its depicted home position and a message will be played. As the turntable completes its full revolution the indexing surfaces of

tabs

93 and 205 of the lever 200 (which travels with the turntable P and thus orbits about the spindle 84) move into contact with the stop shaft and tab 206 of the bellcrank 207. The tab 205 pivots the bellcrank 207 in the direction shown by arrows. This pulls the linkage arm 212 generally toward the spindle 84 and pivotally displaces the driven wheel 217 about the drive shaft 220 in the same general direction. This also pivots the sleeve bearing 213, stretches the spring 222 and removes the drive wheel 215 from the flange 89.

The turntable P is slowed by means of a cam 95 and follower, as explained in the aforementioned Geils, et al. patent, which absorbs energy from the turntable and returns the play arm to its rest position. The turntable thus stops at the approximate position shown in phantom lines in HO. 1 with the tab 93' of the lever 200 bearing against the stop shaft 92a, the tab 205 bearing against the bellcrank 207 and the spring biasing the still driven driving mechanism including the wheel 217 against the motor drive shaft 220. The bias of the stretched spring 222 is insufficient to overcome the inertia of the turntable and the frictional detent of the cam 95 and its follower.

When the program advance mechanism detects that another message is to be played, it removes the stop shaft 92a. The spring 222 while of insufficient strength to move the entire turntable is of sufficient strength at this point to shift the linkages including the lever 200 back to its other extreme position (solid lines in FIG. 1) and to cause the drive wheel 215 to move back into contact with the flange 89 of the turntable P. The drive wheel imports sufficient drive to the turntable to move it, and the cam 95 and its follower mechanism return the playing arm to the record. The drive wheel 215 quickly raises the turntable P up to operating speed and at the completion of the revolution the operation is repeated again to stop the turntable in its home position.

As should now be apparent a novel improvement on audiovisual educational apparatus having several advantages has been described. The turntable drive release mechanism for such an apparatus allows the turntable to be stopped relatively more rapidly. It prevents scuffing of the drive wheels friction surface and also, as the home" position is also the storage position for the mechanism, prevents flat spots from developing on the drive wheel when the apparatus is left unused for an extended time. This latter defect, of course, is one of the prime causes of distortion in the reproduction of sound from a record.

In addition, the inventive mechanism allows the motor and drive wheel to be run continuously at the desired speeds during periods of use, even when the turntable is stopped, so as to be able to start and reach the proper turntable rotational speed quicker and also so as to prevent excessive number of start-up current loads from being placed on the electric motor windings.

While a particular embodiment of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. ln audiovisual educational apparatus of the type having a support frame, a turntable mounted on the support frame for rotation relative thereto, a drive assembly mounted on the support frame and including drive means for rotating the turntable, the drive assembly being movable between a driving position, in which the drive means is engaged with the turntable, and an idle position, in which the drive means is out of engagement with the turntable, and stop means mounted on the support frame in a fixed location corresponding to a home" position of rotation of the turntable relative to the support frame, the stop means being movable between an operative position and an inoperative position; the improvement comprising index means carried by the turntable in a position for engagement by the stop means when the turntable approaches the home" position and the stop means is in its operative position, the index means being operable in response to engagement by the stop means and further rotation of the turntable toward the home" position to urge the drive assembly to its idle position, the index means cooperating with the stop means when engaged thereby to prevent the turntable from rotating beyond the home" position.

2. The improvement in audiovisual educational apparatus defined in claim 1, including means for moving the stop means between its operative and inoperative positions in accordance with a predetermined audiovisual program and responses to the audiovisual program effected by an operator.

3. The improvement in audiovisual educational apparatus defined in claim 1, wherein the index means comprises a lever pivotally mounted on the turntable for movement relative thereto between an actuated position and a null position, the lever having a first surface spaced from the pivotal axis and engageable by the stop means to hold the lever in its actuated position, the lever having a second surface spaced from both the first surface and the pivotal axis and engageable with the drive assembly.

4. The improvement in audiovisual educational apparatus defined in claim 3, wherein the drive assembly includes a bellcrank pivotally mounted on the support frame, the bellcrank having a first arm positioned for engagement with the second surface of the lever, and a second arm operatively connected with the drive means; and means biasing the drive assembly toward its driving position, the biasing means being selected to provide a force insufficient to withstand the urging of the drive assembly to its idle position by the lever when the lever is engaged by the stop means but sufficient to urge the drive means into driving engagement with the turntable at all other times.

5. The improvement in audiovisual educational apparatus defined in claim 4, wherein the pivotal axes of the lever and of the bellcrank are parallel with each other and with the axis of rotation of the turntable.

6. In an audiovisual educational apparatus comprising:

means defining a visual display station;

means for receiving an image support carrying a plurality of spaced visual images, the image support further including code means;

means for effecting relative movement between the image support and the visual display station;

an audio reproduction system including a pick-up head;

a drive mechanism including a turntable for driving an audio record relative to the pick-up head, the record having a plurality of messages recorded thereon in spaced relation;

a releasable stop for stopping the turntable at a home" position;

means for effecting relative movement between the pick-up head and the record to select an audio message;

synchronization means for positively correlating the position of the image support, relative to the display station, with the position of the pick-up head, relative to the record, the synchronization means including positioning means adapted to provide a positive, incremental relative movement between the audio record and the pick-up head in response to a corresponding incremental movement of the image support;

a responder mechanism including a plurality of manually operable key elements for making selective responses to audio and visual information presented;

means actuated by the manually operable key elements coacting with the code means for regulating the relative movement between the image support and the display station;

the drive mechanism including an electric motor mounted below the turntable and having a drive shaft, a driven wheel, an axle affixed to the driven wheel, and a drive wheel affixed to the axle for driving the turntable when engaged therewith;

the improvement wherein the drive mechanism further includes a link arm forming a bearing at one end thereof in which the axle is journaled, a spring affixed to the link arm for biasing the driven wheel into driven engagement with the drive shaft of the electric motor, and for urging the drive wheel toward the turntable for frictional drive thereof when engaged therewith, a bellcrank pivotally affixed beneath the turntable and having one end pivotally affixed to the other end of the link arm, a lever carried on and rotated with the turntable and being mounted thereon for limited pivotal motion, the lever having a first bellcrank in a direction in which the link arm is moved to urge the drive wheel out of engagement with the turntable while maintaining the driven wheel in engagement with the motor drive shaft, thereby storing energy in the spring for returning the drive wheel to engagement with the turntable upon release of the stop.

Claims

1. In audiovisual educational apparatus of the type having a support frame, a turntable mounted on the support frame for rotation relative thereto, a drive assembly mounted on the support frame and including drive means for rotating the turntable, the drive assembly being movable between a driving position, in which the drive means is engaged with the turntable, and an idle position, in which the drive means is out of engagement with the turntable, and stop means mounted on the support frame in a fixed location corresponding to a ''''home'''' position of rotation of the turntable relative to the support frame, the stop means being movable between an operative position and an inoperative position; the improvement comprising index means carried by the turntable in a position for engagement by the stop means when the turntable approaches the ''''home'''' position and the stop means is in its operative position, the index means being operable in response to engagement by the stop means and further rotation of the turntable toward the ''''home'''' position to urge the drive assembly to its idle position, the index means cooperating with the stop means when engaged thereby to prevent the turntable from rotating beyond the ''''home'''' position.

6. In an audiovisual educational apparatus comprising: means defining a visual display station; means for receiving an image support carrying a plurality of spaced visual images, the image support further including code means; means for effecting relative movement between the image support and the visual display station; an audio reproduction system including a pick-up head; a drive mechanism including a turntable for driving an audio record relative to the pick-up head, the record having a plurality of messages recorded thereon in spaced relation; a releasable stop for stopping the turntable at a ''''home'''' position; means for effecting relative movement between the pick-up head and the record to select an audio message; synchronization means for positively correlating the position of the image support, relative to the display station, with the position of the pick-up head, relative to the record, the synchronization means including positioning means adapted to provide a positive, incremental relative movement between the audio record and the pick-up head in response to a corresponding incremental movement of the image support; a responder mechanism including a plurality of manually operable key elements for making selective responses to audio and visual information presented; means actuated by the manually operable key elements coacting with the code means for regulating the relative movement between the image support and the display station; the drive mechanism including an electric motor mounted below the turntable and having a drive shaft, a driven wheel, an axle affixed to the driven wheel, and a drive wheel affixed to the axle for driving the turntable when engaged therewith; the improvement wherein the drive mechanism further includes a link arm forming a bearing at one end thereof in which the axle is journaled, a spring affixed to the link arm for biasing the driven wheel into driven engagement with the drive shaft of the electric motor, and for urging the drive wheel toward the turntable for frictional drive thereof when engaged therewith, a bellcrank pivotally affixed beneath the turntable and having one end pivotally affixed to the other end of the link arm, a lever carried on and rotated with the turntable and being mounted thereon for limited pivotal motion, the lever having a first portion for engagement by the releasable stop as the turntable approaches its ''''home'''' position, and a second portion for engaging the other end of the bellcrank when the first portion is engaged by the stop; whereby, as the turntable approaches its ''''home'''' position, the stop and the other end of the bellcrank are engaged with the first and second portions of the lever to pivot the bellcrank in a direction in which the link arm is moved to urge the drive wheel out of engagement with the turntable while maintaining the driven wheel in engagement with the motor drive shaft, thereby storing energy in the spring for returning the drive wheel to engagement with the turntable upon release of the stop.