US2370875A

US2370875A - Automatic phonograph control mechanism

Info

Publication number: US2370875A
Application number: US472442A
Authority: US
Inventors: Pressley Jackson Hard
Original assignee: Farnsworth Television and Radio Corp
Current assignee: Farnsworth Television and Radio Corp
Priority date: 1941-01-22
Filing date: 1943-01-15
Publication date: 1945-03-06
Anticipated expiration: 1962-03-06

Description

March 6, 1945. ss 2,370,875

AUTOMATIC PHONOGRAPH CONTROL MECHANISM Original Filed Jan. 22, 1941 2 Sheets-Sheet l INVENTOR H. PRESSLEY March 6, 1945- J. H. PRES/SLEY 2,370,875

AUTOMATIC PHONOGRAPH CONTROL MECHANISM Original Filed Jan. 22, 1941 2 Shets-Sheet 2 FIG. 2 v

F k A, I i' 3e 25 j 23 2| 5 )r I f 40 58 5 i i l 35 l 1' TI" 11 F|G.4 ,Ao l 34 INVENTOR Patented Mar. 6, 1945 AUTOMATIC PHONOGRAPH CONTROL MECHANISM Jackson Hard Pressley, Marion, Ind., assignor to Farnsworth Television and Radio Corporation, a corporation of Delaware Original application January 22, 1941, Serial No. 375,389. Divided and this application January 15, 1943, Serial No. 472,442

3 Claims.

This invention relates to an automatic phonograph, and more particularly to new and useful improvements in pickup arm control mechanisms. This application is a division of my copending application, Serial No. 375,389, filed January 22, 1941. now Patent No. 2,313,262, granted March 9, 1943.

The principal object of the present invention is to provide an improved mechanism for controlling the movement of the pickup arm used with the record-changing apparatus so that the stylus of the reproducer engages a record on the turntable with the least possible pressure.

In accordance with the present invention, there is provided a phonograph comprising a turntable, a pickup arm with a reproducer .at one end thereof for cooperating with a record on the turntable, a supporting means for the pickup arm, cam means, and pickup arm control means. The pickup arm control means is associated with the cam means and is adapted to engage the pickup arm intermediate the reproducer and the supporting means for moving the reproducer into engagementwith the outer groove of the record on the turntable.

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 steps will be pointed out in the appended claims.

In the accompanying drawings:

Fig. 1 is a top planview of a pickup arm in playing position upon a record;

Fig. 2 is an assembly view, partly in section, of the pickup arm moving mechanism;

Fig. 3 is a side elevation view of the pickup arm moving mechanism; and

Fig. 4 is a view taken on line 4--4, of Fig. 3, showing a cam and associated mechanism for controlling horizontal movement of the pickup Means for playing the record |2 comprises-areproducer l3 with a stylus l4 (Fig. 2) which cooperates with the record on the turntable The reproducer I3 is supported at the free end of pickup arm IS, the other end of which is mounted on the pedestal l6 so that it can pivot in a vertical plane on two points at different times and can be swung in a horizontal plane around the axis of the pedestal. The pedestal I6 is provided with a hollow rotatable shaft IS in which a pin I9 is adapted to move vertically (Fig. 2). To the top of the shaft I8 is afiixed a plate 2| which is adapted to move over the top of the pedestal IS with the least possible friction. To' one end of the plate 2|, a plate 22 is connected by means of a pin 23. Intermediate its ends, the plate 22 is provided with a bearing portion 25 which supports, by means of a pin 26, a bracket 21 fixedly secured to the pickup arm l5, as shown in Fig. 2. The pickup arm I5 is affixed to the bracket 21 so as to pivot on the bearing pin 26 when the stylus of the reproducer is in engagement with a record on the turntable. A suitable weight 30 is provided in the pivoted end of the pickup arm 28 to maintain a predetermined stylus pressure on a record on the turntable.

The pickup arm i5 is raised and lowered with respect to-a record on the turntable by means of pin i9 together with cam surface 33 on cam wheel 34. The cam wheel 34 is amxed to drive shaft 35 which may be driven through a mechanism shown and fully described in my copending application, identified hereinbefore. As shown in Figs. 2 and 3, the

portions

32 and 36 of cam surface 33 cooperate in raising and lowering the pin l9 and thereby in raising and lowering the plate 22. Screw 38 at the other end of the plate 22 engages the pickup arm i5 (Fig. 2) and raises it out of cooperative relationship with a record on the turntable.

After the pickup arm [5 has been raised, the

cam wheel 34 has rotated to the position where an inclined portion 40 of a cam surface 4| engages apin 42 fixed to a lever 43 which is connected to the lower end of the shaft l8 (Figs. 2 and 3) to rotate therewith. The continued rotation of the cam wheel 34 moves the pin 42 and therewith the lever 43 outwardly in a horizontal plane. After the inclined portion 40 of the cam surface 4| has moved past the pin 42, the lever 43 has positioned the pickup arm l5 beyond the edge of the record on the turntable l, as shown in dotted lines in Fig. 1.

While the cam surface 4| is in engagement with the pin 42, a pin 48 is in engagement with a'cam surface 41 (Fig. 3) of the cam wheel 34. The pin 46 is secured to the free end of a springbiased lever 48 which is aflixed to a rod 50, to the upper end of which is amxed a lever 5| (Fig.

3). The rod 50 is mounted on the base plate It! to move in a vertical direction. The contour of the cam surface 41 is shown in dotted and full lines in Fig. 3. Immediately after the pick up arm has been swung to its outermost position, the portion 53 of the cam surface 41 moves into engagement with the pin 46. This raises.

the pin 46, the rod 50 and the lever 5|. The rod 50 is raised against the biasing action of spring 54. Immediately after the lever 5| is raised, the pin l8 moves off of the portion 36 of cam surface 33. This allows the pickup arm to come into engagement with a pin 55 affixed to the free end of the lever 5| During the time the pickup arm is being lowered into engagement with the pin 55 and for a short timethereafter, the cam surface 56 (Fig. 4) is in engagement with the pin 46 which prevents the pickup arm from moving. inwardly. Immediately after a record has been placed on the turntable, the notch 58 in the cam surface 56 (Fig. 4) allows the pin 46 which is under the biasing action of a spring 6|) (Fig. 4) to move so that it transmits inward movement to the pickup arm. One end of the spring 66 is anchored to the lever 48 and the other end is anchored to a pin 6| which may be afiixed to the underside of the base plate In. After the pin 46 is in engagement with the portion 58A of the notch 58, the pickup arm has been moved inwardly sufficiently far to position the stylus M of the reproducer l3 over the outer groove of a ten-inch record on the turntable.

If a twelve-inch record is on the turntable II, the pickup arm I5 will be swung inwardly until a fiber roller 65 on the lever 5| engages the peripheral edge of the twelve-inch record. This engagement positions the stylus of the reproducer over the outer groove of a twelve-inch record.

As the cam wheel 34 continues to rotate, a portion 66 of cam surface 41 moves under the pin 46. This allows the spring 54 to force downwardly the rod 50 and therewith the levers 48 and 5|. The downward movement of the lever 5| positions the stylus of the reproducer l3 into engagement with the outer groove of a record on the turntable. After the stylus is in engagement with the outer groove of the record on the turntable, the continued movement of the cam surface 41 allows the pin 46 to move into the notch 61 of the cam surface 41 (Fig. 3). This allows the levers 48 and 5| to be lowered still further. The further lowering of the lever 5| moves the pin 55 out of engagement with the pickup arm I5. After the pin 55 is out of engagement with the pickup arm I5, a portion 583 of the. notch 58 moves into engagement with the pin 46. The continued movement of the cam wheel 34 causes the pin 46 and the arm 48 to move in a counterclockwise direction (Fig. 4) against the biasing action of the spring 60 to the position shown in Figs. 1 and 4. When the pin 46 and the lever 48 have been moved back to the latter position, the driving mechanism previously referred to for the record-chan ing apparatus is automatically shut off and reproduction of a record on the turntable is begun.

In operation, the pickup arm |5 moves inwardly toward the center of a recordon the tumtable II as the stylus l4 follows the playing grooves of the record. As the pickup arm l5 moves inwardly, the pin 42 likewise moves inwardly in a clockwise direction, (Figs. 2 and 4). When the stylus l4 reaches theinnermost or tripping groove of a record, the mechanism is tripped in the manner fully described in the aforementioned application, and the drive shaft (Fig. 2) is rotated.

As the shaft 35 and cam wheel 34 begin to rotate, the portion 32 of the cam surface 33 (Fig. 3) engages and lifts the pin l9, whereby its upper end engages the under side of the plate 22 causing it to pivot on pin 23 and thereby move.

the screw 33 into engagement with the pickup arm l5 (Fig. 2). Immediately thereafter, the high point of the cam surface 33 moves under the pin l8, whereby the plate 22 is moved upwardly sufllciently far to lift the pickup arm I5 and the stylus l4 out of engagement with the record |2.

When the cam wheel 34 has rotated to such a position that the stylus I4 is lifted out of engagement with the record l2 (Fig. 2), the angular portion of the cam surface 4| (Fig. 4) has moved into engagement with the pin 42 (Figs. 2 and 4). Continued rotation of the cam wheel 34 causes the pin 42 and the lever 43 to move outwardly in a counterclockwise direction (Figs. 2 and 4). By the time the pin 42 reaches the end of the angular portion 40, the lever 43 and therewith the pickup arm I5 is moved to the position wherein the pickup arm I5 is at its outermost position beyond the edge of the record on the turntable, as indicated by dotted lines in Fig. 1 of the drawings.

Immediately after the pickup arm has been moved to its outermost position, the cam wheel 34 rotates to such a position that the portion 53 of the cam surface 41 (Fig. 3) engages and moves the pin 46 and therewith the levers 48 and 5| vertically upward. The pin l9 then moves oil of the cam portion 33 (Fig. 3) to lower the pick up arm l5 into engagement with the pin of the lever 5| (Fig. 3). v

Shortly after the record on the turntable has been reversed or a new record has been moved into playing position on the turntable, the cam wheel 34 rotates to such a position that the pin 46 engages the notch 58 of the cam surface 56 (Fig. 4) to allow the coil spring 60 to move the levers 48 and 5| and therewith the pickup arm I 5 inwardly. When the pin 46 engages the por-- tion 58A of the notch 58, the pickup arm I5 is approximately over the outer groove of the record on the turntable.

Continued rotation of the cam wheel 34 causes the eccentric portion 66 of the cam surface 41 (Fig. 3). to engag the pin 46, allowing the pin 5|) and the levers 48 and 5| gradually to lower the pickup arm and the stylus into engagement with the outer groove of the record on the turntable. When the notch 61 moves under the pin 46, the spring 54 forces the lever 5| and pin 55 out of engagement with the pickup arm l5, whereupon the cam portion 583 engages and moves the pin 46 and therewith the levers 48 and 5|.outwardly to the position shown in Fig. 1. Immediately thereafter, the driving mechanism for the cam wheel-34 is stopped and reproduction of the record on the turntable takes place.

While there has been described what is at present-considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Whatis claimed is:

1. A phonograph comprising a turntablepa pickup arm including a reproducer for cooperating with a record on said turntable, supporting means for said pickup arm, elevating means operativeiy associated with said supporting means for lifting and lowering said pickup arm, rotatable means connected to said supporting means for moving said pickup arm outwardly from the center of a record on said turntable, cam means associated with said elevating means and said rotatable means for operating them in timed relation and a pickup arm control means operatively associated with said cam means and movable thereby to engage and support said pickup arm intermediate said reproducer and said supporting means when the pickup arm is being lowered by said elevating means for moving said pickup arm inwardly and downwardly into engagement with the outer groove of the record onsaid turntable.

2. A. phonograph comprising a turntable, a pickup arm including a reproducer for cooperating with a record on said turntable, supporting means for said pickup arm, elevating means operatively associated with said supporting means for lifting and lowering said pickup arm, rotatable means connected to said supporting means for moving said pickup arm outwardly from the center of a record on said turntable, cam means associated with said elevating means and said rotatable means for operating them in timed relation. a pickup arm control means adapted to engage and support said pickup arm intermediate said reproducer and said supporting means when the pickup arm is being lowered by said elevating means, and cam means operatively associated with said pickup arm control means for moving said pickup arm inwardly and downwardly into engagement with the outer groove of the record on said turntable.v

3. A phonograph comprising a turntable, a pickup arm including a reproducer for cooperating with a record on said turntable, supporting means for said pickup arm, a vertically disposed pin operativeiy associated with said supporting means for lifting and lowering said pickup arm, rotatable means connected to said supporting means for moving said pickup arm outwardly from the center of a record on said turntable, cam means associated with said pin and said rotatable means for operating them in timed relation, a pickup arm control means adapted to engage and support said pickup arm intermediate said reproducer and said supporting means when the pickup arm is being lowered by said pin, cam means operatively associated with said pickup arm control means for moving said pickup arm control means inwardly and downwardly, and stop means on said pickup arm control means for engaging said record and guiding said repro- 4 ducer into engagement with the outer groove of the record on said turntable.

- JACKSON HARD PRESSLEY.