US2458623A

US2458623A - Control means for gramophones

Info

Publication number: US2458623A
Application number: US595371A
Authority: US
Inventors: Mortimer Edmund Walter
Original assignee: Garrard Eng & Manufacturing Co Ltd
Current assignee: Garrard Eng & Manufacturing Co Ltd; GARRARD ENGINEERING AND MANUFACTURING Co Ltd
Priority date: 1943-11-05
Filing date: 1945-05-23
Publication date: 1949-01-11
Anticipated expiration: 1966-01-11

Description

'Jan. 11, 1949. E. w. MORTIMER CONTROL MEANS FOR GRAMOPHONES Filed May 23, 1945 2 shets sheet l IN VEN TOR. it/mill; wake/'fiaflizkwf Jan. 11, .1949. E. w. MORTIMER 2,458,623

COI {THOL MEANS FOR GRAMOPHOI IES I Filed May 25, 1945 2 sheets-sheet 2 INVENTOR. Edmund M/ter/Zmizknm Patented Jan. 11, 1949 UNITED"- STA'TES PATENT OFFICE CONTROL MEANS FOR GRAMOP-HONES Edmund Walter lii ortimer, Swindon, England, assignor to The-Garrard Engineering and Manu- .-facturing-Company Limited Swindon, England Application May 23, 1945, Serial No. 595,371 ,In Great Britain November-5, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires February 5,1963

8 Claims. (01. l92-. 123) This invention relates to gramophones or the like,and more specifically to means for automatically cutting off thedr-iving-motor and actuating the turntable brake at the end of the playing of a record.

The invention has particular reference to control mechanisms for gramophones of the type wherein the sidewise movement efiected by the tone arm or .pick-up when the needle enters the quick pitch groove at the center of arecord, is utilized to cause theappropriate parts to function. In mechanisms of this type,,there is usually developed a.relatively.considerable resistance to the radial progression of the tone arm during the playing of the record and owing to the ex- ,tremelylightloading obtaining with tone arms and pick-upset present employed, the needle is therefore frequently caused to leave the reproduction groove of therecordwith the consequent spoiling of the reproduction.

It is an object of the presentinvention to provide an improved-motor cut-off and turntable brake control mechanism which is particularly adapted to functionwith light loaded tone arms thereby overcoming the aforementioned shortcomings.

- 1 Another, object of theinvention-is to provide trigger means or the-like, movable from the tone arm adapted toy-cause the actuation of means for cutting :off the motor and applying the turntable the position-of the parts ofthe control mecha- ,;nism after operation "of thetmechanismaupon brake at the end of the playing of the record and ineffective to. cause .such actuationwhile the --needleis in the reproduction grooves of arecord, and novel means for neutralizing the movement of the triggermeansand restoring the: same to The invention also contemplates the provision of a switch and brake unit incorporating a relay orsolenoidland adapted to cut off the motor and actuate the turntable brake upon energization of therelay, the unit being connected. inlan electric circuit controlled bya switch the closing whereof is caused by the actuation .of .means by the movement of the .tone arm, when the needle enters the run outgroove of a record.

These and othertrelated objects will become apparent in the: following description, of the invention illustrated in the drawings, wherein:

Fig.- 1; is a plan ,view ,illustratinga. motor and .turntable brake control-mechanism according to the invention.

Fig. 2 is a side elevation of the mechanism of Fig. 1.

Fig. 3 is a plan'viewjsimilar-to Fig.- "l-showing their initial position at eachrevolution of the turntable.

completion of the playing of --a record.

' F'ig. 4 is an elevation; partlyin section, of the rotaryswitch and brake unit forming part of the control mechanism.

Fig. 5 is a top plan view-of the unit of Fig. 4,

with part of the upperstructure thereof removed,

showing theposition of theswitch contacts during theplaying of the-record.

Fig. 6 is a plan;view similar-to Fig.;5 showing the position of theswitch contactsupon actuation of the control mechanism.

Fig. '7 isa fragmentary plan iew illustrating a modified embodiment ofthe invention.

In the accompanying drawings, the invention ,-is illustrated, bywway of example, as applied to ,a rgramophone wherein the motor is cut ou after the playing of each record," and therecords are changed, manually.

Referring nowin detail to thedrawings, l indicates the ,tone arm-of thev instrument having associated therewith. for conjoint movement about the axis of rotation of the tone arm,,a quadrant 2. The quadrant is providedwithaterminal rim 3 which 1 projectsupwardly through a slot 4 in the motor platform 5.

-A fibreblockor pad Bis carried at the free end the quadrant-rim 3 may be such that the rim becomes efiective-towards the end of the playing .ofa record.

-- The arml of thebell-orank lever'8 normally lies substantially on ya line joinin :its own pivot Hand the tone'armw pivot lztand is-normally held in such position by a spring l3wconnected to the lever and to aljstudld onthe supportin plate 9. g

The other arm l5 of the bell crank lever is adapted to close aswitch 16 -mounted on the motor platform and included in a low tension circuit, the function whereof ,will becomelater apparent.

...,The supportingplateii for the bell crank lever is providedwithan arm 11 whichextends toward and, terminates in the .vicinityof theturntable spindle. l8 laterally thereof. The spindle l.8.car-

riesfor, rotation, therewith a boss .I 9, of insulating material, and a permanent magnet 20 is mounted in a suitable recess of the boss.

The free end of the arm I! of the supporting plate 9 is provided with an upstanding soft iron bar 2i located close to the insulating boss l 9, the arrangement being such that, at each revolution of the turntable spindle ill, the magnet 20 will attract the bar 2| and cause a rotation of the supporting plate 9. A light loading spring 22 suitably connected to the plate 9 and to a stud 23 projecting from the motor platform 5, (See Figs. 1 and 3) causes the plate to return to its initial position.

Due to the conformation of the supporting plate 9, the displacement of the arm I! thereof caused by the magnet 20 is effective to move the fibre pad 6 carried by the arm 1 of the bell crank lever out of contact with the quadrant rim 3, so as to allow the bell crank to return to its normal position under the action of its spring l3. As soon as this return movement is efiected, the magnet 20 moves away from the bar 2| due to the continued rotation of the spindle, and the plate 9 is returned to normal position bringing the pad 6 again into engagement with the quadrant rim 3. The movement of the arm I! of the plate 9 may be limited by adjustable stops 24. As will be apparent, this removal of the pad 6 from the quadrant rim 3 occurs at each revolution of the record while the needle is in the playing groove.

The amount of rotation of the bell crank lever 8, caused by the movement of the tone arm by the playing grooves of a record is insufficient to displace the bell crank arm l to a position to close the switch [6, owing to the pitch of the grooves. When, however, the needle enters the run out groove, the pitch of this latter is such as to cause a substantial radial movement of the needle during one revolution of the record, which is sufficient to determine the closing of the switch 56.

The closing of the switch l6 actuates means for cutting off the motor and applying the turntable brake which are as follows:

A rotary switch and brake unit 25 (see Figs. 1, 4 and 5) supported by the motor platform 5 underneath the turntable, comprises an electro magnet 26 which is connected in a low tension circuit with the switch l6 and is mounted in a housing 21. A rotatable spindle 28 extends axially of the electro-magnet and has secured to its lower end a lever or detent 29. An armature plate 30 pivotally carried by the housing 21 has a terminal downwardly bent portion 3| normally extending through a slot 32 of the detent 29. The upper end of the spindle 28 carries for rotation therewith a brake lever 33 for the turntable and an insulating drum 34 incorporating a plurality of contact elements 35, which are normally in contact with elements 36 (see Fig. 5) mounted on the housing 21, said

contact elements

35 and 36 forming a two-pole rotary switch inserted in the motor circuit. A spring 31, connected to the drum 34 and to a stud 38 carried by the housing 21, tends to rotate the drum rotation of this latter and therefore of the spindle 26, brake lever 33 and detent 29 being however normally prevented by the engagement of the armature plate 30 with the detent.

Upon closing of the switch [6 when the pickup needles enter the run out groove of a record through the mechanism hereinbefore described, the electro-magnet 26 is energized and the armature plate 30 is attracted to the electro-magnet thereby releasing the detent 29, whereupon the spring 31 causes the drum 34 and associated elements to rotate, thus applying the brake 33 to the turntable rim and causing the contact elements 35 to move away from the elements 36 to the position shown in Fig. 6, thereby breaking the motor circuit to stop the motor.

If desired, the switch drum 34 and the housing 2'! may carry suitably connected additional contacts to break the low tension circuit to the electro-magnet upon actuation of the rotary switch.

The detent 29 is pivotally connected at 38 to a link 39, which in turn is pivoted at 40 to the free end of a lever 4i pivotally mounted on the motor platform 5 as at 42. A rod 43, pivoted at 44 intermediate the ends of the lever Al and slidable between guide studs 45, carries at its free end an upstanding stud or pin 46. This stud is engageable by the quadrant 2, rotatable with the tone arm I, so that, by moving the tone arm horizontally away from the turntable, the rod 43 may be displaced to return the detent 29 and associated elements to their normal position through the lever 4| and the link 39 thereby releasing the turntable brake 30 and closing again the rotary switch formed by the

contact elements

35, 36. The switch [6 will be concurrently opened again by the return of the bell crank 8 to its normal position following the displacement of the quadrant 2.

Since the electro-magnet 26 has meanwhile become de-energized due to the opening of the switch Hi, the armature plate 30 is allowed to fall by gravity and to re-engage the detent lever 29 whereby the mechanism is locked again in its normal position. If desired, a spring may be provided in association with the armature plate to overcome residual magnetism.

The embodiment of Fig.7 differs from the structure hereinbefore described in the provision of a bell crank 48 pivoted on the plate 9 having an arm 49 in the form of a scar of trigger. The scar is adapted to engage the nose 59 of a lever 5|, the latter controlling the motor and turntable brake through any suitable mechanism, not shown. The normal movement of the sear 49 caused by the rotation of the bell crank, when the needle is in the playing groove, is insufficient to release the nose 59 of the lever 5|, and the rotation of the bell crank is neutralized, at each revolution of the turntable, as in the foregoing embodiment, to maintain the desired overlap of the sear 49 with the nose 59. When the needle enters the run out groove of the record, the sear is caused to effect a displacement suflicient to release the nose 59, whereupon the mechanism controlled by the lever 5i is allowed to operate to effect the cutting off of the motor and the braking of the turntable.

Although the invention has been described specifically in connection with the cutting off of the motor and the actuation of the turntable brake of a gramophone, it is within the province of this invention to employ my novel mechanism in a magazine type gramophone for controlling the operation of the means through which the record changing operation is efiected.

It is understood that changes and modifications may be made in the structures described and illustrated in the drawings without departing from the spirit of the invention or exceeding the scope of the claims.

I claim:

1. In a gramophone comprising a turntable, an electric motor for driving the turntable, a turntable brake, a tone arm and means including a relay for'cutting off the motor'and actuating the turntable brake, a switch in circuit with said relay, a quadrant movable with the tone arm, an oscillatable support, a bell crank pivotally mounted on said support and having one arm normally maintained in engagement with said quadrant to cause the bell crank to rotate simultaneously with the movement of the tone arm, the other'arm of the bell crank'being adapted to actuate said switch to operate said relay upon a predetermined rotation of the bell crank greater than the rotation thereof caused by the quadrant during one revolution of theturntable while the pick up needle is in the reproduction groove of a record, means for periodically oscillating-said support at each revolution of the turntable to disengage the'bell crank from the quadrant, and means for. returning the bell crank to a predetermined initial angular position relatlv-e to the support upon oscillation of this latter.

2. In a gramophone comprising a tone arm, a turntable, an electric motor for driving the turntable, a turntable brake and means including a leveroperable to cut off the motor and actuating the turntable brake, a quadrant movable with the tone arm, an oscillatable support, a bell crank pivotally mounted on said support and having one arm normally maintained in engagement with said quadrant to cause the bell crank to rotate concurrently with the movement of the tone arm, the other arm of the bell crank embodying a sear normally engaging said lever, the rotation of the bell crank by a predetermined amount greater than the rotation thereof caused by the quadrant at each revolution of the turntable while the pick up needle is in the reproduction groove of a record causing release of the lever by the sear and operation of the means for cutting off the motor and actuating the turntable brake, means for periodically oscillating .said

support at each revolution of the turntable to disengage the bell crank from the element, and means for returning the bell crank to a predetermined initial angular position relative to the support u-pon oscillation of this latter.

3. In a gramophone comprising a turntable, an electric motor for driving the turntable, a turntable brake, a tone arm, and means including a relay for cutting oii the motor and actuating the turntable brake, a switch circuit with said relay, a quadrant movable with the tone arm, an oscillatable support, a bell crank pivotally mounted on said support and having one, arm engaging said quadrant to cause the bell crank to rotate concurrently with the movement of the tone arm, the other arm of the bell crank being adapted to actuate said switch upon a predetermined rotation of the bell crank, a permanent magnet carried by the turntable spindle for rotation therewith, the support aforesaid having an arm extending into the path of the field of said magnet and carrying an armature element adapted to be attracted by the magnet at each revolution of the turntable, whereby the support is oscillated to disengage the bell crank from the quadrant, and means for returning the bell crank to a predetermined initial angular position relative to the support upon oscillation of this latter.

4. In a gramophone comprising a turntable, an electric motor for driving the turntable, a turntable brake, a tone arm and means operable to cut off the motor and actuate the turntable brake, a switch for controlling said means, a quadrant movable with the tone arm and having a rim, an'oscillatable support, a bell crank pivotally mounted on said support and having one arm carrying a friction element normally maintained in engagement with said quadrant rim to cause the bell 'orank to rotate relative to the support simultaneously with the movement of the tone arm, the other arm of the bell crank being adapted to actuate said switch upon a predetermined rotation of the bell crankgreater than the rotation thereof caused by the quadrant rim during one revolution'of the turntable while the pick up needle is in the reproduction groove of a record, means for periodically oscillating the support at each revolution of the turntable to disengage said friction element of the bell crank from the quadrant rim, and spring means for returning the bell crank to its initial angular position relative to the support upon oscillation of this latter, whereby to neutralize the rotation of the bell crank at each revolution of the turntable.

5. In a gramophone having a tone arm, a turntable, an electric motor for driving the turntable, a turntable brake, and means operable to cut off the motor and actuate the turntable brake, an

oscillatable support, means for normally holding said support in a predetermined position, a member pivoted to said support, resilient means for normally holding said pivoted member in a predetermined angular position with respect to said support, an elementmounted for rotation about the pivot of the tone arm and rigidly connected with said tone arm, said element normally engaging said pivoted member and causing it to rotate with respect to said support simultaneously with the movement of the tone arm, the rotation of the pivoted member beyond a predetermined amount operating said means for cutting off the motor and actuating the turntable brake, and means for oscillating said support at each rotation of the turntable to disengage said pivoted member from said element, whereby said resilient means returns said pivoted member to its predetermined angular position with respect to said support, before said predetermined amount is reached, to neutralize the rotation of said pivoted member at each revolution of the turntable while the pick up needle is in the reproduction groove of a record.

6. In a gramophone having a tone arm, a turntable, an electric motor for driving the turntable, a turntable brake, and means including a relay operable to cut ofi the motor and actuate the turntable brake, an oscillatable support, means for normally holding said support in a predetermined position, a member pivoted to said support, resilient means for normally holding said pivoted member in a predetermined angular position with respect to said support, a switch operating said relay when closed, an element mounted for rotation about the pivot of the tone arm and rigidly connected with said tone arm, said element normally engaging said pivoted member and causing it to rotate with respect to said support simultaneously with the movement of the tone arm, the rotation of the pivoted member beyond a predetermined amount causing said switch to be closed, and means for oscillating said support at each rotation of the turntable to disengage said pivoted member from said element, whereby said resilient means return said pivoted member to its predetermined angular position with respect to said support, before said predetermined amount is reached, to neutralize the rotation of said pivoted member at each revolution of the turntable while 7 the pick up needle is in the reproduction groove of a record. I

7. In a gramophone having a tone arm, a turntable, an electric motor for driving the turntable, a turntable brake, and means comprising a lever operable to cut off the motor and actuate the turntable brake, an oscillatable support, means for normally holding said support in a predetermined position, a member pivoted to said support, said member embodying a sear normally engaging said lever, resilient means for normally holding said pivoted member in a predetermined angular position with respect to said support, an element mounted for rotation about the pivot of the tone arm and rigidly connected With said tone arm, said element normally engaging said pivoted member and causing it to rotate with respect to said support simultaneously with the movement of the tone arm, the rotation of the pivoted member beyond a predetermined amount causing the release of said lever by said sear and therefore the cutting off of the motor and the actuation of the turntable brake, and means for oscillating said support at each rotation of the turntable to disengage said pivoted member from said element, whereby said resilient means return said pivoted member to its predetermined angular position with respect to said support, before said predetermined amount is reached, to neutralize the rotation of said pivoted member at each revolution of the turntable while the pick up needle is in the reproduction groove of a record.

8. In a gramophone comprising a turntable, an electric motor for driving the turntable, a turntable brake, a tone arm, and means operable to cut ofi the motor and actuate the turntable brake, a quadrant movable with the tone arm, an oscillatable support, a bell crank pivotally mounted on said support and having one arm normally maintained in engagement with said quadrant to cause the bell crank to rotate with respect to said support simultaneously with the movement of the tone arm, the other arm of the bell crank being adapted to actuate said means for cutting off the motor and actuating the turnable brake upon a predetermined rotation of the bell crank greater than the rotation thereof caused by the quadrant during one revolution of the turntable while the pick up needle is in the reproduction groove of a record, means for periodically oscillating said support at each revolution of the turntable to disengage the bell crank from the quadrant, and means for returning the bell crank to a predetermined angular position relative to the support upon oscillation of this latter.

EDMUND WALTER MORTIMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,004,059 Means Sept. 26, 1911 1,813,483 Clark July 7, 1931 1,895,004 Nystrom Jan. 24, 1933 2,083,314 Carson June 8, 1937 2,116,056 Wilkinson May 3, 1938 2,259,251 Kamp Oct. 14, 1941 2,295,460 Farrow, Jr. Sept. 8, 1942