US2073042A - Automatic stop for phonographs - Google Patents

Description

March 9, 1937. A. F. zl-:MAN 2,073,042

AUTOMATIC STOP FOR PHONOGRAPHS Filed April 29, 1929 Patented Mar. 9, 1937 UNITED STATES 2,073,042 Y .i AUTOMATIC STOP FOR PHONOGRPHS` Arthur F. Zeman, Chicago, Ill., assiginor to Radio Corporation of America, New York, N. YI., acorporation of Delaware f Application April 29, 1929, Serial No. 358,768 1 Claims.

My invention relates to an automatic stop for graphophones or the like which is particularly adapted for use in connection with that type of machine known as a gramophone which uses at 5 circular disc records, some of which terminate in v means of an electric motor.

The principal objects of my invention are to provide simpleand novel means for automatically breaking the electric circuit of the record rotatingv motor when the record has been completely played, and to provide such means which may conveniently be housed within the base part of a tone =arm or the equivalent part of a so-called electric pickup or like device.

Another object of the invention is to provide automatic stop means such as above referred to which will be operative in connection with various makes of records respectively provided with various forms of terminal grooves. For example, Victor records terminate in a continuous groove 3'0 which is eccentric to the center of the record and its sound grooves, and Brunswick and Columbia terminate in a concentric groove spaced radially inwardly from the last sound groove but connected thereto by a spiral groove. Still further objects of the invention are to provide automatically stopping means which may be easily reset to complete the motor circuit; to provide such means which will be compact and readily mountable within the tone arm or like part so as to be 40 effectively concealed; to provide such means of simple construction and operation so as to be not readily rendered inoperative; and, in general, it

is the object of my invention to provide an improved automatic stop of the type referred to.

Other objects and advantages of the invention will be understood by reference to the following specication and accompanying drawing, in which I have illustrated an automatic stop embodying the features of my invention, one preferred form being illustrated.

In the drawing:

i Fig. 1 is a plan showing my automatic stop mechanism mounted within the base part of a phonograph tone arm, the tone arm being shown in section.

(Cl. 192-124) I K Fig. 2 is a vertical section onithe line 2-2 of Fig. 1.

Fig. 3 is va section on the linef3-'3 of Fig. 1, certain parts being broken away or entirely omitted so as to more clearly illustrate other parts.

Fig. 4 is an elevation of a part ofthe mechansm indicated by the line 4-4 of Fig. 1.

Fig. 5 is a plan showing the operation o! the device with a recordhaving a concentric terminal groove spaced radially inwardly from the nal sound groove and connected to the latter by means of a spiral groove; andV Fig. 6 is a view similar to Fig. 5 illustrating the n stopv mechanism applied to a record having an eccentric terminal groove.` Y

Referring now to the drawing, the baseboard or motor board of a phonograph or gramophone of any well known type' is indicated at 6. VA tone arm 9, which in this instance is provided with a bearing sleeve I0, is pivotally mounted on anupright post or shaft II which is carried by a base plate I2, the latter being suitably secured to the base board 6. The post or shaft II may be secured to the plate by means of a reduced end portion of the post which fits in an opening in the plate I2 and is headed over as indicated at I3. The post has an enlargement I4 near itsA lower end forming a shoulder at the top on which the bearing sleeve I0 rests and whereby the tone arm is adapted to turn freely as an incident to the playing of records. l

A contact supporting post I5 is mounted on the plate I2throulgh an opening therein and is electrically connected to the motor by means of a conductor 'I. The contact post is electrically insulated from the plate through the medium of a sectional insulating bushing I5A of hard rubber or other dielectric material substantially as shown, particularly in Fig. 4. 'To the post I5, a resilient contact member is attached which may consist of a plate I1 provided with a bent down flange like part I8 at one edge and a spiral arm I 9 coiled around the insulating bushing I 5A'as best shown in Fig. 1. The spiral arm isin effect a continuation kof the flange partIB and at its free end is provided with -a hardened contact 20. The spiral arm -obviously servesy to resiliently or yieldingly maintain the contactv20 in predetermined position. v Y

Pivoted to the base plate I2 on the enlargement I4 of the post I I is a cross arm 22 which may be limited in its pivotal movement and retained in position in any suitable manner, for instance, by means of a screw 23 anchored in the base plate and extending through an arcuate slot 24 in the arm, the head 25 of the screw serving to retain the arm in operative position and pivotal movement of the arm being limited by the length of the arcuate slot. One end of the cross arm extends over a recess 2I in the plate I2 and carries a contact supporting post 26 similar to the contact supporting post I5, the contact post 26 beingljconnected by means of a suitable conductorl 8A to ab source Si of electric current. It will, of course, be understood that the motor is provided with another of the current supply lines. 'I'he post 26, being carriedbyv the pivoted cross arm 22 is a movable post. `A contact elem-ent secured to this post includes a plate 21 having a flange-like part 28 depending therefrom and a hardened contact point 29 adapted to engage with the contact point 20 to complete or cross the by a spring 30 which is anchored at one end to the plate I2 and at its other end to the cross arm l22, so that the tension yof the spring will normally maintainthe movable contact 29 in engagement with the relatively stationary contact 20.

One edge of the cross arm 22 is cut away or otherwise provided with a wall portion 32 which is eccentric to the... center or axis of a pivoted lever or pawl 34, the latter being pivoted intermediate its ends, as indicated at 35, to the base plate I2. The outer end ofy the lever or pawl 34 has a vertical abutment member 36 preferably formed by bending an end portion of the pawl upwardly.

A, tension spring 31 connected between the outer arm of the lever 34 andthe base plate I2 serves to cause the end 33 of, the pawl to frictionally engage the eccentric wallpart32 of the cross arm and, as will-hereinafter be `more fully explained; thereby toy retain the cross arm 22 in any position towhich itmay be shifted.

v The plate I2 may be secured to the motor board orbase boardG within the base part of the tonearm 9 by means such as screws 38, and an opening 39 is provided in the base plate and base board through which conductor wires may be passed when my automatic stop structure is used in connection with aA so-called electric pickup which is used on a phonograph instead of the usual sound box and tone arm, for reproducing the recordfthrough the agency of a radio receiving set. As indicated in Figs. 5 and 6, the phonograph includes a turn table 40 driven from the shaft 4I of the electric motor (not shown) which, in practice, is often suspended from the motor. board 6.

AA detent or dog 431s pivoted as shown at 42 on the end of the cross arm 22 remote from the contact carrying end thereof, the free end 44 of the dog being urged to move outwardly by a spring 45 Awhich is suitably lstretched between the dog 43 and the base plate I2, preferably as shown in Fig.,1. Pivotal movement of; the dog 43 under the-influence ofthe spring 45 is limited under someconditions by meansof a stop pin 3I which isso positioned that vthe outer, operative end 44 ofthe dog 43 is normally positioned closely adjacent-the inside of the tone arm 9. A part having vrneansfor actuating the stop mechanism so far described is mounted on the inside of the tone arm 9 and consists of a metal strip 4 6 which may be riveted` or otherwise securedto the tone arm at suitable points as indi-A cated at 41. This strip` is preferably provided with integrally formed, 'inwardly projecting .cir-

cumferentially spaced ears 48 and 49, which constitute starting and stopping members respectively. The inner surface of the strip adjacent to the stop member 49 is provided with ribs or serrations as indicated at 50, which are adapted to cooperate with the end 44 of the detent 43. Under some circumstances, the serrations 50 serve as the stopping member instead of the ear 49.

The operation of the device is as follows, when playing a record having a spiral groove terminating in an inwardly spaced circular concentric groove: As shown in Fig, 1, the parts are in the position in which they appear when a record has been almost but not quite completely played. The iinal travel of the tone arm in a crosswise direction, from the sound grooves 56 of the record to the concentric terminal groove 51, caused by the spiral connecting groove 54 (Fig. 5), will cause the stop ear 49 to engage the abutment member 36 of the pawl 34 and thereby rock the latter on its pivot 35. Obviously, the inner end 33 of the pawl 34, acting against the eccentric, cam-like edge portion 32 of the pivoted cross arm 22, will rock the cross arm against thevtension of the spring 30 so as to movelthe contact.

29 out of engagement with the stationary contact 20, thereby breaking the motor circuit and causing the motor to stop. The cross arm 22, pawl 34 and starting and stopping ears 4 8 and 49 will then be in the position shown in brokenlines in Fig. 1. The pawl 34 will be maintained in its operative, broken line position by the spring .31 until reset, as will presently bedescribed. In standard practice, the records which are provided with the above described concentric terminal and spiral connecting gIQOVeare made to a predetermined standard wherein theconcentric circular grooves are all of approximately the same diameter regardless of the length of the record. In other words, a record having sound grooves extending across substantially all of the available recording space as shown in Fig. 5 terminates in a concentric groove of the same diameter as the concentric groove ofV a record having sound grooves extending only a part of the way across the available sound groove space, the said concentric groove being connected by means of a spiral groove such as 54 in both cases. Hence, the tone arm is in all cases moved to substantially the same final, stopping position.

Records of the type which are provided with an eccentric groove do not terminate in a. standardized eccentric groove, Vit being the practice to form the eccentric groove without regard vto the final stopping position of Ythe tonev arm. Hence, it is not ysafe to dependV upon theengage# ment of the stop ear 49 withthe abutment 36 of the pawl 34 to stop the mechanism when playing records provided with eccentric grooves.- For the purpose of insuring proper stopping of the phonograph mechanism when such records have been completely played, I have provided the above described ribs or serrations 50 and cooperating dog 43.v

When playing an eccentric groove record, the operation is as follows: Itwill be understood that the eccentric grooveV 52 of a record having sound grooves 5I (Fig. .6) will cause the tone armr to oscillate azlimited amount4 substantially as indicated between thefull line and broken line position in Fig. 6. If the eccentric groove52 happens to be of suitable diameter and properly located, the extent of oscillating movement of thetone arm maybe sucient of. itself to actuate the stop mechanism, but in many cases the: emu,-

tric groove is of such a large diameter that the stop lug 49 is not brought into operative engagement with the abutment 36 of the pawl 34. In such cases, the outer end 44 of the dog 43 engages the ribs 50 of the part 46 so that, when the tone arm is rocked in a counter clockwise direction by the eccentric groove, pivotal movement in a counter clockwise direction will be imparted to the cross arm 22 through the dog 43. Hence, the contacts 29 and 2D will be separated to break the electric circuit. It will be seen that when the tone arm is moving in a clockwise direction during the playing of the record, the dog 43 will merely ride the ribs 50 because of the relative arrangement of the parts, but that on counter clockwise movement of the tone arm, the dog will not readily slip over the ribs since the dog tends to become wedged between the ribs and the pivot 42, the spring 32 assisting to-maintain the dog in operative engagement with thesaid ribs. It will be seen that when the cross arm 22 is rocked through the agency of the dog 43, the pawl 34 will be rocked by the spring 3l so that the end 33 of the pawl will engage another portion of the eccentric or cam-like wall part 32 to lock the cross arm 22 in open position, i. e., in the position in which the contacts 29 and 20 are separated.

For resetting the stop mechanism so as to establish engagement between the contacts for completing the electric circuit, the tone arm is manually swung in a counter clockwise direction to a position somewhat outwardly of the outer edge of the phonograph turn table whereby the starting ear 48 is caused to engage the abutment 36 of the pawl 34 and to swing the latter against the tension of the spring 3l into inoperative position substantially as shown in full lines in Fig. 1. The dog 43 will not prevent such action since under suilicient manually applied pressure, either the spring 45 will yield to permit the dog to slip over the ribs or the spring 30 will yield to permit the cross arm 22 to move to its extreme open position in which the stop pin 3l will prevent the outer end 44 of the dog from engaging the ribs 50.

As best shown in Fig. 3, the starting and stopping ears 48 and 49 are formed by slotting lower marginal portions of the strip 46 and bending the ear portions inwardly. Thus the upper marginal portion of the strip remains a continuous surface over which the end 44 of the dog 43 will readily pass without actuating the stop mechanism. The resilient mounting for the contact member 20 is not necessary although it is desirable since it insures the establishment of good electric contact between the contact points 29 and 2U, it being understood that the resiliently supported contact 20 is yieldingly held, when the contacts are separated, in a position somewhat beyond its normal position when the contacts are in engagement.

It will be seen that the automatic stopping device which I have thus described is operative to stop rotation of the records both by inward movement of the tone arm beyond the end of the sound groove of a record and on outward movement of the tone arm in a path located inwardly of the last turn or coil of the spiral sound groove. The ribbed segment and dog arrangement which eiects separation of the contacts upon outward movement of the tone arm is such that the dog rides freely over the ribs upon inward movement of the tone arm and,.

hence does not interfere with the normal operation o f the phonograph nor with the control of the motor by means of the pivoted pawl and eccentric cross arm surface engaged thereby.

The base plate I2 of the automatic stop mechanism is preferably made more or less skeleton in form so that there will be a minimum of ob.- struction in the tone arm to the passage of the sound Waves. up device is used, a more or less solid plate such as herein illustrated, may conveniently be used, a suitable opening or openings being provided for the passage of the necessary electric conductors. y

I have thus provided a comparatively simple Y automatic stopping device which may be manufactured at a comparatively low cost and which is universally operative with the various types of stop actuating grooves used in standard practice. Obviously, suitable changes may be made to adapt my device to other conditions and I am aware that the above described construction may be changed without departing from the spirit of my invention, the scope of which should be determined by reference to thev following claims, the same being construed as broadly as possible consistent with the state of the art.

I claim as my invention:

1. In an automatic stop device for phonographs having a pivoted tone arm which is normally swung on its pivot as an incident to the playing of a record, and a driving motor for rotating the record, the combination of means mounted entirely within the tone arm for controlling the operation of the motor and actuated by the tone arm as an incident to its pivotal movement. l

2. In an automatic stop device for phonographs having a pivoted tone arm which is normally swung on its pivot as an incident to the playing of a record, and a driving motor for rotating the record, the combination of means Of course, where an electric pickf mounted entirely within the tone arm for controlling the operation of the motor and actuated by the tone arm as an incident to its pivotal movement, and means actuated as an incident to reverse pivotal movement of saidtone arm for resetting said automatic stop to permit operation of said motor.

3. In a phonograph having an electric motor for rotating the records to be played and an electric circuit for actuating said motor, a pivoted tone arm carrying means engaging the records whereby the tone arm is swung on its pivot as an incident to the playing of the records, and means mounted within the tone arm for controlling said electric circuit, said means being operative to control said circuit so as to stop the motor as an incident to pivotal movement of the tone arm inwardly, beyond the end of the sound groove of the record.

4. In a phonograph having an electric motor for rotating the records to be played and an electric circuit for actuating said motor, a pivoted tone arm carrying means engaging the sound groove of the records whereby the tone arm is swung on its pivot as an incident to the playing of the records, means mounted Within the tone arm for controlling said electric" circuit, said means being operative to control said circuit so as to stop the motor as an incident to pivotal movement of the tone arm inwardly, beyond the end of the sound groove of the record, and means actuated as an incident to reverse pivotal movement of said tone arm for resetting said automatic stop to permit operation of said motor.

' spiral lead in or the eccentric kind, an electric 5. In a device of the class described and in-g and to be moved to allow said detent member to combination with a phonograph having a rotatable turntable and a pivoted tone arm with a sound reproducing device carried thereby, meansw for rotating said turntable, and means mounted f 6. A phonograph adapted to play grooved diskrecords having run-over grooves Ofeither the motor for rotating the disks, a swinging arm, a groove-following stylus carried by the arm and by which the arm is swung, a pair of circuit make and break contacts in circuit with the motor, a circuit opener, yielding means normally holding the circuit opener in circuit open relation, means operable by the swinging of the arm back to starting position for setting said opener in non-operative position, and means operable by the forward swinging of the arm due to a record having a spiral lead in run-over groove or by the rearward swinging of the arm due to a record having an eccentric run-over groove adapted to release the opener from non-operative position as and for the purpose specied.

'7. In a disk playing phonograph, a turntable, an electric motor for rotating the turntable, a swinging arm, a groove-following stylus carried by the arm, a pair of cooperating contacts in circuit with the motor, a movable lever adapted to open the circuit, a swinging lever adapted to hold the movable lever in non-operative position, means associated with the arm for setting the swinging lever in holding position upon the rearward swinging of the arm back to starting position, and other means associated with the arm for moving said swinging lever to non-holding position upon the completion of playing a record,

with a run-over groove of the concentric kind.

8. A control mechanism for phonographs com detent member to-hold it in' the off position move into the on position, a sound reproducing instrumentality, a member adapted to be moved by said instrumentality, and detent restoring means adapted to cooperate with said latch member whereby said detent member may be restored to on position by the manual operation of said instrumentality.

9. A phonograph adapted to play grooved disk records having run-over grooves of either the spiral or the eccentric kind, means for rotating the disks, Aa swinging arm, a groove-following stylus carried by the.V arm and by which the arm is swung, a base lupon which` the arm .is mounted for its swinging movement, means assocated with the base for controlling the disk rotating means and operable to be set in record rotatingposition and in record non-rotating position, means operable for retaining the controly means in either of its two positions, a projection carried by the arm forv setting the control means in record rotating position when the arm is swung back to begin playing a record, means carried by the arm adapted to release the control means from its record rotating position upon the advancement of the arm to a predetermined position dueto a record with a spiral run-over groove, and other means carried by the arm for releasing the control means from its record rotating position upon: the backward swing of .the arm due to a record having an eccentricrun-over groove.:

10.., In a disk playing phonograph, a turntable, an electric motor for rotating the turntable, a swinging arm, a groove-following stylus carried; by the arm, a pair of cooperating contacts in circuit with the motor, a movable latch lever upon which o-ne of the contacts is mounted, a swinging lever adapted to hold the latch-lever in circuit closed position, means associated with the swinging arm for setting the latch in circuit closing position when the arm is swung back to begin playing a record, and other means associated with the arm for releasing the latch and permitting the separation of the contacts upon the ad'.- vancement of the stylus into a run-over groove at the center of a recordv being played.

ARTHUR F. ZEMAN.

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