US2301091A - Automatic phonograph - Google Patents

Description

NOV# 3, 1942- E. o. ,'rHoMPsoN Au'rouATIc PHoNocRAFHr s shets-sheet 1 Filed Nov. 14, 19.40

mw 1. Y 1 Y N0V- 3, 1.942- E. o. THomPsoN AUTOMATIC FHONOGRAPH 3 Sheets-Sheet 2 Filed NOV. 14, 1940 1^? 'WMU/ IH'. u lr $1 m.

Nov. 3, 1942. E. ogrHoMPsoN l 2,301,091

Y AUTOMATIC PHONOGRAPH Filed NOV. 14, 1940 3 ShOBtS-Shet 3 llnlllllllw Patented Nov. 3, 1942 AUTOMATIC PHONOGRAPH Elmer O. Thompson, Grasmere, N. Y., assignor to Philco Radio and Television Corporation, Philadelphia, Pa., a corporation of Delaware f Application November 14, 1940, Serial No. 365,708

2Claims.

This invention relates to automatic phonographs of the type embodying a trip mechanism responsive to the rate of movement of the pickup or reproducer over the record being reproduced. Such a trip mechanism is adapted to operate at the end of a record when the pick-up stylus engages aspecial groove having a greater pitch than the grooves in the main portion of the recording.

The trip mechanisms of this character which have-been employed heretofore have been objectionable in that they may operate at the beginning of a record when the pick-up is moved laterally to place the stylus in the initial grooves of a record. The undesired operation of the trip mechanism in such instances is a source of annoyance since it causes the recording to be rejected by the phonograph without being reproduced.

The principal object of the present invention is to provide an improved automatic phonograph mechanism which eliminates this objection of prior devices.

Amore specic object of the invention is to provide in combination with a speed-responsive trip mechanism a novel means for preventing operation of the trip mechanism during the initial part of the reproduction of a record.

The invention may be clearly understood by reference to the preferred form thereof illustrated in the accompanying `drawings, in which:

Fig. 1 is a perspective view illustrating the parts of the phonograph with which the invention is concerned;

Fig. 2 is an elevational view of the mechanism; and

Fig. 3 is a perspective view taken from a difierent angle to show the tone arm lifting device.

The automatic phonograph illustrated comprises the usual turntable I for supporting one or more sound records 2 and having the usual central spindle 3, driven by suitable means (not shown) preferably taking the form of an electric motor and reduction gearing. The tone-arm l is pivotally mounted in cooperative relation with the turntable by means of the pivotal mounting designated generally by reference character 5. The tone-arm is also pivotally connected to its support at the upper end thereof for raising and lowering movement. Thus as is customary, the tone-arm is adapted to be raisedor lowered and is also adapted to move laterally over a record when in lowered position. Both the turntable and the tone-arm 4 are mounted upon a common supporting table i.

The tone-arm carries a suitable pick-up or reproducer 'which includes the' needle or `stylus 1. The pick-up is adapted to translate" the nndulations of the record grooves into corresponding electrical currents which are supplied to an amplifier and thence to a loud-speaker, as is well understood. y

As illustrated in Fig. 3, the tone-arm 4 is adapted to be raised from the record 2 by means of a raising and lowering device l which is carried by the rotatable support 5. Y prises a member 8 pivotally attached to support 5 at I0. The member 9, in turn, carries a second member II which is pivotally attached to member S by means of the pivot pin I2. The member Il has a downwardly-extending actuating arm I3 and another extending arm Il to which a lift member I5 is pivotally attached at I8. The lift member I5 carries at its upper end a rod I1 whose upper end is adapted to engage the tonearm. The lift assembly comprising member I5 and rod I1 extends through an opening I8 in the supporting table 8 to permit movement of the lift mechanism as the tone-arm support I rotates.

The lifting device 8 is actuated by means of a pivoted arm I9 whose operation will be described later. For the present, it suilices to state that when the member II is actuated by arm I8 in a counter-clockwise direction, as viewed in Fig. 3, the lift member I5 is raised, bringing the upper end of rod I'I into engagement with the tone-arm. Continued upward movement of the lift-arm I5 causes the tone-arm l to be lifted off of the record 2. In the meantime, however, the weight of the tone-arm acts to rotate the entire lifting mechanism about the main pivot I U, thereby to initiate operation of a means for moving the raised tone-arm so as to l condition it for repeated playing of the record or the playing of a succeeding record. The present invention is not directly concerned with this latter means and for the present purpose a brief description thereofwill suffice. The member l has an extending arm 20 on the end of which there is provided a cam follower 2l which is adapted to seat in an eccentric cam groove provided in the upper face of a disk 22 which is geared to the turntable shaft by means of the gear 23 on the disk, gear 2l on the turntable shaft, and an intermediate gear 25. The cam groove acting through arm 20 serves to rotate the tone-arm support 5 thereby rotating the tone-arm about its vertical pivot.

mechanism for rotating the tone-arm through an The device 8 com` Since this oted cam follower v upper ends by means of arc when it is in Iraised position is well known and since the present invention is not directly concerned with it, it is unnecessary to illustrate or describe the said mechanism in further detail. Hence it has been deemed unnecessary to illusa trate the cam groove in the upper surface of disk 22.

Thepresent invention is concerned, however, withan additional function of the rotating disk 22 which results from spaced projections 255 on the underside of the peripheral portion oi' the disk. The purpose of these projections will be described later.

Referring now to Figs. l. and 2, the arm i8 is shaped as illustrated and is pivoted at 21 to a supporting bracket 28 carried by the supporting table 8. 'Ihe free end of arm i9 is curved as i1- lustratec'. and is adapted to engage and actuate the tone-arm lifting device as shown in Fig. 3. 'I'he arm I9 is adapted to be actuated by a cam 29 carried by the rotating disk 22. I'he cam actuation of arm I9 is effected by means of a piv- 35 on the said arm. The arm I9 has'turned-up lugs 3| and 32 which serve as stops for the element 30 which is normally maintained against stop 32 by means of spring 33 secured at one end to a lug 34 on element 38 and at. its' other end to a lug 35 on arm I9. The arm I9 is urged toward operative position by a spring 38 secured at one end to the lug 35 and at its opposite' end to a lug 31 on bracket. 28. Normally, however, the arm I 9 is latchecl in inoperative position against the action of spring 35 by a latch :member 38 which is pivoted at 39 to the supporting bracket 28. The latch member has a hook like end which engages a small knob 48 on arm I9. The latch member 38 is urged to latching position by spring 4I, one end of which is anchored to the stationary support or bracket 28. When the arm I9 is latched in inoperative position as shown in Fig. 1, the element 30 is out of the path of cam 29 and, therefore, the cam is free to rotate without actuating arm I9.

, The latch member 38 is adapted to be actuated by means responsive to the rate of movement of the tone-arm over a record which will now be described. On the'tone-arm support 5, there is mounted a clutch member 42 which, together with a second clutch member 43, forms a friction clutch. The two clutch members 42 and 43 may take the form of clutch disks having frictionallyengaging faces, as will be well understood. The lower clutch member 43 is carried by a sleeve 44 which is slidably mounted on the rotatable tonearm shaft 45. A spring 48 is arranged to malntain the clutch member 43 in engagement with the yupper clutch member 42, This spring is seated 'in a retaining disk or washer 4l loosely mounted on the shaft 45 and adjustable to a de-.

sire'd position by means of adjusting nuts 48 and a screw 49 secured to the lower end of shaft 45.

The lower clutch member.43 has an extending arm 50 at the end'of which there are turned-up elements I and 52 which are connected at their a screw 53 and a coil spring 54 thereon. 'I'he element 5I constitutes a latch-tripping member and it is disposed adiacent to a shoulder 55 on the latch member 38. By means of the screw 53-and associated spring 54, the position of element 5I may be slightly adjusted in relation to the shoulder 55. It will be seen that rotation of arm 50 through clutch l 42-1-43, as the tone-arm moves inward over a record, will tend to bring the latch-tripping element 5I into engagement with the shoulder 55.

turntable driving means,

The latch-tripping mechanism further comprises a pivoted bracket 58 which is plvotally mounted on a stationary bracket 51 carried by the support 28. The plvoted bracket 58 comprises a plurality of superposed arms I8, 59 and 88 which are riveted together at one end and which have their opposite ends relatively adjustable by meansA of adjustment screws 5I. The lowermost arm 58 has its end extended at 82 and this extended end engages a shoulder 83 on sleeve 44. 'Ihe uppermost arm 88 has a tumed-up extension 54 which ride' over the lower peripheral surface of disk 22 and engageable by the spaced projections 25 thereon. During the engagement of roller 58 disk surfaces between the projections ment with one another by spring 48. However, when one of the projections 28 engages the roller 85, the multi-arm bracket 55 is rotated slightly counter-clockwise, as viewed in Fig. 2, thereby moving the clutch member 43 out of engagement with clutch member 42 as illustrated in Fig. 2. Thus, at regular intervals determined by the speed of rotation of disk 22 and the spacing of projections 25 thereon, the clutch members 42 and 43 are temporarily disengaged. This periodic operation of the clutch member serves to rotate the arm 55 counterclockwise a slight amount each time the clutch. is disengaged.

The above-described parts of the tripping mechanism are so constructed that the mechanism is not tripped as long as the tone-arm moves over the record at the stylus is traversing the sound grooves oi' the record. During such normal movement of the tone-arm, the slight movement of the arm 58 occurring between successive disengagements of the clutch 42-43-,is insuillcient to' actuate the latch member 38. Each time the clutch members are disengaged as above-described, the lower clutch member returns to normal engaged position by virtue of the tension of spring 45. Since the intervals at which the clutch members 42 and 43 are disengaged are fixed by the xed spacing ofprojections 25 and the constant speed or rotation of disk 22 driven from the constant speed the operation of the is dependent entirely of the tone-arm as it latch-tripping member 5I upon the rate of movement traverses a record.

As stated previously, the purpose of the tripping mechanism is to operate the tone-arm lifting device at the end of a record and also to interrupt the playing of a record and lift the tonearm in the event that the tone-arm moves too rapidly at any time. The operation of the tripping mechanism at the end of a record is brought about when the stylus or needle 1 engages a special groove which causes the tone-arm to move rapidly inward. At such time or in the event that the tone-arm should move laterally too rapcam 29 causes pivotal movement of arm I9,

carries a roller 85 adapted to virtue of the action oi its normal rate or speed while bringing the curved end thereof into engagement with arm I3 of the tone-arm-lifting device, as shown in Fig. 3. The cam 29 maintains the arm I9 in its effective position during the movement of the tone-arm to the beginning of a record by means of the arm 20 as above described. After the tone-arm has been thus moved, the cam 29 releases element 30, permitting it to move back against stop 32. 'I'he arm I9 is thereby permitted to move back to its latched position out of., engagement with the tone-arm-lifting device. Consequently, the parts of the tone-arm-lifting device are restored by the weight of the tone-arm and by gravity to the positions of Fig. 3, the stylus being deposited at the beginning of the record. -To limit the counter-clockwise movement of the arm 50, a suitable stop (not shown) may be provided together with a linkage (not shown) to maintain the clutch 42-43 disengaged during the interval when the arm I9 is displaced from its rest position. These elements have not been illustrated since they are well known and are not essential to the present invention.

In order to prevent the trip mechanism from operating at the beginning of a record, there is provided a detent bar orlink 88 which has o ne f end pivotaliy attached to clutch member 42 at The opposite end of bar 6l is slidably retained by guide means 10 on the supporting bracket 2l. The bar B8 has a shoulder 1i which engages arm 5I during the iirst part of a record reproduction and prevents the arm ll from tripping the latch member 38. Since the bar II moves toward the left, as viewed in Fig. 1, during the inward movement of the tone-arm, the shoulder 1| is moved past arm Il after a predetermined interval and thereafter the latch member Il may be tripped by arm Si asdescribed above depending no the rate of movement on the tone-arm. The bar ll'thus prevents objectionabletripping of the mechanism at the beginning of a 'record in the event that the stylus is moved laterally due to any cause. When the mechanism is tripped and the tone-arm is moved back to the beginning of the record, the bar 6l is returned to its effective position, as shown in Fig. 1.

It will be seen that the invention provides a trip mechanism for an automatic phonograph which is responsve to the speed or rate of movement of the pick-up or reproducer and which by a simple and novel means is prevented from operating during the initial portion of the reproduction. Thus, the invention eliminates undesirable tripping lof the mechanism which has been an objectionable characteristic oi prior defined by the appended claims.

Iclaim:

1. A stopping mechanism for a phonograph having a pivotally mounted reproducer, said mechanism comprising means for automatically stopping the reproduction of a recording, a movable trip member for actuating said stopping means, said trip member having a normal inoperative position and an operative position to which it is movable from its normal position, means for coupling said trip member to said reproducer so'that the reproducer drives said trip member toward its operative position, means for periodically decoupling said last-named means and returning said trip member to its normal position so as to prevent actuation of said stopping means during normal movement of the reproducer, and means for rendering said trip member ineective during the playing of a part of a recording, said last-named means comprising a movable member adapted 'in certain positions to 4 prevent the advance of said trip member, and operatively connected to said reproducer eccentrically of the pivot thereof so as to be movable by the motion o; the reproducer over the recording.

2. A stopping mechanism for a phonograph having a pivotally mounted reproducer, said mechanism comprising means for automatically stopping the reproduction of a recording, a movable trip member for actuating said stopping means. said trip member having a normal inoperative position and' an operative positionto which it is movable from its normal position, a

clutch comprising driving and driven disksarranged coaxially with the reproducer piv'otgfor coupling said trip member to said reproducer sothat the reproducer drives said trip member toward its operative position, means for periodically disengaging said clutch disks and returning said trip member to its normal position so as to prevent actuation of said stopping means during normal movement of the reproducer, and means for` rendering said trip member ineffective during the playing of a part' of a recording, said last-named meanscomprising a longitudinally movable bar.

pivotally connected to the driving clutch disk eccentrically of the reproducer pivot, said bar having a shoulder thereon which engages said trip member during apart of the movement of the bar and thereby prevents the advance of the trip member.

ELMER O. THOMPSON.

Images