US2366858A - Pickup arm mounting - Google Patents

Description

Jan. 9, A KNQXHETAL V PICKUP 1mm MOUNTING ori inal Filed Dec. 31, 1940' 2 sheets-sheet 1 FlGll INVENTORS ARTHUR L. KNOX FR AHL BY wdkdam ATTOR N EY Jan. 9, 1945. L KNOX ET AL 2,366,858

PICKUP ARM MOUNTING Original Filed Dec. 31, 1940 2 sheets sheet 2 Q28 FIG. 2

lN -VENTOBS ARTHUR L. KNOX F remain... 9, 1945 PICKUP ARM MOUNTING Arthur L. Knox and Fritz Kahl, Fort Wayne, Ind., assignors to Farnsworth Television and Radio Corporation, a corporation of Delaware Original application December 31, 1940, Serial'No. 372,681. Divided and thls application April 3 19:13, Serial No. 485,176

2 Claims.

7, invenion relates to an automatic phonograph and more particularly to new'and useful improvements in pickup arm mounting. This applicationis a division of our application, Serial No. 372,681,,fi1ed December 31, 1940, which issued as Patent No. 2,332,650, Oct. 26, 1943.

An object of the present invention is to proup arm has been moved to its'outwardmost position; and

Fig. '7 is a fragmentary view taken on line 1-1 of Fig. 2 showing the mechanism for controlling the inward movement of the pickup arm to position the stylus over the initial playing groove of vide an improved mounting for a pickup arm used with record-changing apparatus.

In accordance with the present invention, there is provided an automatic record-changing apparatus including a turntable, a pickup arm, and a supporting means for said pickup arm. For supporting the pickup arm, there is provided a shaft with a first bearing element and an elevating means associated with 'the shaft. A member with a second bearing element is adapted to pivot on the first bearing element of the shaft. The second bearing element is adapted to' pivotally support the pickup arm when a stylus of the pickup arm is in engagement with a record on the turntable.

A pivot transfer or stop means is associated with the member and is adapted to engage the pickup arm when the elevating means moves a stylus of the pickup arm out of engagement with a record on the turntable. Upon the engagement of the pivot transfer with the pickup arm, the pivotal movement of the pickup arm is transferred from the second bearing element to the first bearing element.

For a better understanding of the invention, together with other and further objects thereof,

. reference is made to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims. In the accompanying drawings:

Fig. l is a fragmentary, side elevation view, partly in section, of the pickup arm support, and

the mechanism for elevating the pickup arm;

Fig. 2 is a fragmentary side elevation view showing the mechanism for moving the pickup arm horizontally; a

Fig. 3 is a perspective view of the pickup arm cam wheel, showing the contour of the cam surface for controlling the horizontal movement of the pickup arm;

Figs. 4, 5 and 6 are fragmentary views taken on line 4-4 of Fig. 2 cmitting'the cam structure for purposes of clarity. There are shown various positions of the members for controlling the horizontal movement of the pickup arm when the stylus of the; pickup arm is at the beginning of a record, when the stylus moves into the trip groove at the end ofa record and when the pick- 'a twelve-inch record.

Referring now particularly to Fig. 1- of the drawings, the invention here illustrated shows a record-playing apparatus which includes a base plate In. Disposed above the base plate I0 is a horizontally rotatable turntable II for support ing a record 52 to be played. The'turntable ll may be rotated by a mechanism shown and fully described in the above-mentioned application.

Means for playing the record l2 comprises a reproducer l3 with a stylus '(Fig. 1) which cooperates with the record on the turntable H. The reproducer, I 3 is supported at the free: end of a pickup arm 15, the other end of which is pivotally mounted on a pedestal Hi to permit the reproducer l3 and the pickup arm 15 to move in horizontal and vertical planes.

When the stylus of the pickup arm l5 reaches the inner groove of a record, the pickup arm is driven by a mechanism disclosed in our copendadapted to engage the cam surface 2|.

. 'a bearing 35 which pivotally supports a bracket elevated and then'swung outwardly in a horizontal plane to a position where it will not interfere with a record-changing cycle.

The means for elevating the pickup arm includes a cam wheel l8 (Figs. 1 and 2) fixed to the shaft I 9; The cam l8 and shaft l9 may be ing application. The cam wheel! has a cam surface 2| with a notched portion 22. A roller 23, which is fixed to one end of a lever 21in is e other endo'f the lever 2Iis connected to a bracket 25 which is suspended from the base plate. l0 (Fig. 1) so that the lever 24 may pivot in a vertical plane. An adjustable screw 26 is supported by the lever 24 intermediate its ends. The screw 26 supports a rod 21 which extends upwardly in a hollow shaft 28. The shaft 28 is rotatable within the pedestal I 6 and is adapted to be moved vertically therein. The shaft 28 has an irregular shaped plate 30 fixed to the top thereof. The plate 30 is adapted to move freely over the top of the pedestal l8. One end of the plate 30 is provided with a bearing 3| which pivotally supports alever 32 by means of a pin 33. Intermediate the ends of the lever 32 there is provided 38 by means of a pin 31. The pickup arm [5 is aflixed to -the bracket 36 so as to pivot on the bearing pin 31 when the stylus of the reproducer I3 is in engagement with a record on the turntable. A suitable weight 38 is provided in the end of the pickup arm 15 as shown in Fig. 1 to maintain a predetermined stylus pressure on the record on the turntable. An adjustable stop com prising screw 40 is provided on the lefthand end of the plate 32 (Fig. 1) to to come into contact with a surface such as 4| just before the stylus is brought out of. engagement with the record as the pickup arm is being elevated. When the cam wheel 18 begins to rotate to elevate the pickup arm out of engagement with a record on the turntable, the roller 23 is in the notch 22. The rotation of the cam wheel 18 moves portion 2|A of the cam surface 2| under the roller 23. The raising of the roller 23 and therewith the lever 24 moves the adjustable screw 26 which raises the rod 21. The raising of the rod 21 moves upwardly the lever 32 which is fixed to the plate 38. The upward movementof the rod 21 and lever 32 lifts the plate 38 and therewith the hollow shaft 28. However, shaft 28 moves upwardlyonly slightly as will be explained hereinafter. As the lever 32 moves upwardly the adjustable stop screw v411 engages the surface 41 and the pickup arm is elevated by pivotal movement about the axis of the pin 33 to lift the stylus out of engagement with the record.

In order to swing the pickup arm outwardly in a horizontal plane, the cam wheel I8 is provided with a cam surface 45, which is adapted to engage a pin 46. The pin 46 is affixed to one end of a plate 41 which is pivoted as at 48 to the base plate l (Fig. 2). The plate "is provided with an aperture 49 (Figs. 4-6) through which pins and. 52 extend- These pins 5| and 52 are affixed near one end of a lever 53, the other end of which is fixed to the shaft 28 (Fig. 1) to move therewith. The outward movement of the pickup arm begins when cam portion 45A of the cam surface 45 moves into engagement with the pin I moves into engagement with the pin 46.

tension of the spring 51, which is sufficient to -46. This moves the plate 41 in aclockwise di- When the stylus of the pickup wise direction (Fig. 5) It is to be noted that any movement of the lever 53 while the pickup arm is out of engagement with. a record on the turntable is against friction created by the engagement of the lever 53 with the base of the pedestal 16 as at 55 (Fig. 1). the lever 53 and the pedestal 16 occurs when the shaft 28, to which the lever 56 is affixed, is raised, as has been previously described. The raising of the shaft 28 brings the upper surface of the annular end of the lever 53 into frictional en agement with the bottom surface of the pedestal l6. The clockwise movement of the plate 41 is against the biasing action of a spring 51 which has one end anchored to the plate 41v andthe other end anchored to a pin 58 depending from the underside of the base plate in (Fig. '7). When the pins 5| and 52 and the plate 41 have reached the position shown in Fig. 6, the pickup arm has been swung to its outwardmost position.

As'the cam wheel l8 continues to rotate the cam portion 453 (Fig. 3) of the am surface 45 The overcome the frictional resistance of .the lever 53 The frictional engagement between 4 pedestal l6 (Fig. 1) thereupon starts to swing the plate 41 in a counterclockwise direction (Fig. 6) causing the right-hand side of the aperture 49 to engage the pin 52 (Fig. 6) and move the pin 52 and therewith the arm 53 in a clockwise direc-, tion (Fig. 6) During this latter movement of the plate 41 and the arm 53, the pickup arm is swung inwardly. When the cam wheel l8 and the pin 46 are in the position shown in.Fig. 3, where the pin 48 engages the flat portion 450, of the cam surface 45, the plate 41-is in the position shown in Fig. 4 and the pickup arm 15 is approximately over the outer groove of a record on the turntable.

, It is to be noted that the inward movement of the pickup arm 15 is slower than its outward movement. ,This allows for the more accurate positioning of the pickup arm over the outer groove of a record on the'turntable. The slower inward movement of the pickup arm is achieved by the shape of the cam 45 which includes the steepportion 45A which acts during the outward movement of the pickup arm and the gradual portion 453 which acts during the inward movement of the pickup arm. The speed of the inward and outward movement of the pickup arm isalso determined by the action of the late 41 on thepins 5| and 52 at different times. When the pickup arm is swung outwardly, the left side of the aperture 49 of the plate 41 (Fi 5) acts on the pin 5|. However, when the pickup arm is being swung inwardly, the right side of the aperture 49 of the plate 41 is acting on the pin 52 (Fig. 6). Since pin 52 is further from the axis of rotation of lever 53 than pin 5!, it is obvious that for a given rate of movement of plate 41 pin 52 moves shaft 28 more slowly than does pin 51.

When the pickup arm I5 is in a position approximately over the outer groove of a record on the turntable the pins 5| and 52 and lever 53 are in the position shown in Fig. 4. Thereupon, the portion 2 IB of the cam surface 2| moves under the roller 23. As the cam wheel l8 continues to rotate, the notch 22 gradually comes into engagement with the roller 23 which allows the lever 24 and the rod 21 to lower the pickup arm and therewith the stylus into engagement with the outer groove of a record on the turntable.

With the lowering of the pickup arm, the lever 53 is brought out of frictional engagement with the pedestal l6.

Due to the fact that the outer grooves of disc records are not at exactly the same distance from their outer edges, the stylus does not always drop exactly into the outer groove of a record. Means are provided for moving the stylus into the outer groove of a record when the record is not provided with a feed-in groove. This means includes a tension spring 62 which is provided on the plate 41 as shown in Figs. 4-6.

- When the pickup arm 15 is swung inwardly by the movement of the plate 41 (Figs. 4 and 6) as previously described, the pin 52 engages and forces the spring 62 outwardly thereby creating a tension on this spring. The tension created is not sufiicient to overcome the frictional resistance of the lever 53 created by its movement against the base of the pedestal 16, but it is suf iicient to swing the lever 53 when it is free of the pedestal Hi. When the pickup arm 15 is swung inwardly by the plate 41, and is lowered into engagement with the record, a heretofore described, and the stylus has not engaged the outer groove of the record, the tension spring 62, which is exerting a force upon the pin 52 (Fig. 4)., thereupon moves the lever 58 and therewith the pickup arm l inwardly sufliciently far to move the stylus of the reproducer into engagement with the outer groove of the record. 7

Means are provided for limiting the inward movement of the pickup arm I 5 so that the stylus may be positioned over the outer margin of a twelve-inch record. This means includes alever 10 which is pivotally supported by a bracket H depending from the underside of the base plate Ill, (Figs. 2 and '7). Disposed intermediate the ends of the lever 10 is a depending ear 12 which is held out'of the path of movement of 2. lug 13 provided "on the plate 41, by means of a flat spring 15 depending from the base plate Ill and engaging the free end of the lever Ill, as

shown in Fig. '7. Near its free end, the lever 18 is provided with a finger 16 which extends upwardly through an aperture 11 provided in the base plate .Il'l (Fig. 7) and extends above the turntable l l a suitable distance as indicated in Fig.7. The location of the finger 15 in relation to the turntable, is such, as to lie in the path of a twelve-inch record, when said record is moved into playing position upon the turntable l I. The mechanism shown and fully described in our copending application may be used for moving, a recordinto playing position upon the turntable When a ten-inch record is placed upon the turntable, the periphery of the ten-inch record will not. engage the finger 16 to release the lever 10. Thus, the plate 41 will swing into its normal position to move the pickup arm over the outer groove of a ten-inch record, as'previously described. When a twelve-inch record is placed into playing position upon the turntable, the periphery of the twelve-inch record engages the finger 18 (Figs. 2 and 7) and moves the lever 18 downwardly out of engagement with the spring catch 15. The lever 10 is released by the spring 15 after the plate 41 has moved the pickup arm l5 to its outermost position asheretofore described. When the plate 4'! acts to swing the pickup arm I 5 inwardly as previously described, the lug 13 engages the car 12, which was released while the twelve-inch record was I placed upon the turntable. The engagement of the lug l3 withthe ear 12 takes place when the pickup arm 15 has been moved inwardly suflicientlyfar to position the stylus over the outer groove of the twelve-inch record. The engagement of the elements 12 and 13 takes place before the flat portion 45C of the cam surface 45 engages the pin 41. However, continued movement of the cam wheel [8 acts to lower the stylus I4 into engagement with the outer groove of the twelve-inch record.

When the twelve-inch record is played and the tripping mechanism previously mentioned, is

actuated, the shaft l9 and therewith the cam engagement with the spring I5, as shown in Fig. l

7. When a new record is moved into playing position .upon the turntable, (if it is a ten-inch record), the mechanism will remain in its normal position to play the ten-inch record. However, if the 'newrecord is a twelve-inch record.

the mechanism will again be set automatically to position the pickup arm over the beginning of the twelve-inch record as heretofore described.

Mode of operation The general mode of operationwill now be described. In this mode of operation it will be assumed that the pickup arm l5 has been positioned to place the stylus M in the initial playing groove of a record on the turntable H, as shown in Fig. 1. As the turntable ll isrotated by a mechanism (not shown) and the record is played, the pickup arm l5 moves inwardly toward the center of the record, as the stylus l4 follows the playing groove of the-record. Asthe pickup arm l5 moves inwardly, the lever 53 is likewise moved inwardlyby means of the tubu lar shaft 28. from the position shown in Fig. 4, to the position shown in Fig. 5.

After the record on the turntable H is reproduced and the stylus I4 of the pickup arm l 5 moves into the tripping groove of the record, a tripping mechanism (not shown) is initiated to start the rotation of the shaft l9; As the cam wheel l8 rotates with the shaft 19 the first operation which occurs, is to lift the stylus M of the pickup arm l5 out of engagement with the record on the turntable H. This operation is brought about by the cam portion ZIA of the cam surface 2| (Figs. 2 and 3) moving into engagement with the-roller 23 on the lever 24 to raise the lever 24 and the adjustable screw 26 from the positions shown in Fig. 2. This movement of the lever 24 raises the rod 21 vertically ,within the tubular shaft 28 (Fig. 1). As the rod in moving in a clockwise direction, moves the stop screw 40 into engagement with the surface 4|. Thereafter the continued upward movement of the pin- 21 raises the pickup arm 15 and therewith the stylus 14 .out of engagement with the record on the turntable l I.

After the pickup arm I5 is raised, the cam portion A of the cam wheel I8 (Fig. 3) engages the pin 46 and moves it, and therewith the plate 41 in a clockwise direction against. the biasing action of the spring 51 from the position shown in Fig. 5. The clockwise movement of the plate 41 moves the left-hand side of the aperture 49, of the plate 41, into engagement with the pin 5| to move the pin 5| and therewith the lever 53 in a counterclockwise direction. The counterclockwise movement of the lever 53 also moves the tubular shaft 28 and the pickup arm l5 in a corresponding direction until the pickup arm I5 is in its out- I wardmost position. -When the pickup arm I5 has been moved to its outwardmost position, the lever 53 and plate 41 are in'the position shown in Fig. 6.

After a new record is placed upon the turntabl l I, in the manner fully described in our copendaperture 49 (Fig. 6). into engagement with the pin 52, and moves the pin 52 and therewith the lever 53 in a clockwise direction. The clockwise movement of the lever 53 also moves the tubular shaft 28 and thepickup arm l in 9. corresponding direction. When the pin 46 reaches the end of the cam portion 45B of the cam wheel l9 (Fig. 3), the plate '41 and the lever 53 are moved to the position shown in Fig. 4, and the pickup arm I5 is approximately over the outer groove of the record on the turntable I I.

Continued rotation of the cam wheel I8 moves the flat portion ZIB of the cam surface 2| (Fig.

2) into engagement with the roller 23.

As the p asoaass What is claimed is: 1. A phonograph apparatus comprising a tumtable: a pickup arm; and a supporting means for said pickup arm including a shaft having a first bearing element on a first side of said shaft, a member adapted to pivot on said first bearing element and having a second bearing element opposite said first side of said shaft, said second bearing element being adapted to pivotally support said pickup arm when a stylus of said pickup arm is in engagement with a record on said turntable, a pivot transfer means associated and therewith the stylus I4 are lowered into en gagement with the record on the turntable ll. Immediately thereafter, the driving mechanism (not shown) for the shaft I9 is shut oil and reproduction of the record takes place.

The next and following cycles of automatic operation of the mechanism are initiated by an automatic tripping mechanism (not shown) which is actuated each time the stylus It moves into a v tripping groove of a record.

table, a pickup arm and a supporting means for said pickup arm including a member having a first bearing element, a lever pivoted at one of its ends to said first bearing element, a second bearing element intermediate the ends of said lever, a pivotal connection between said second bearing element and said pickup arm, a stop means at the other end of said-lever and spaced from said pickup arm, and elevating means operatively associated with said lever.

ARTHUR n. KNOX. FRI'IZ KAI-IL.

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