US2239359A

US2239359A - Stylus head mounting

Info

Publication number: US2239359A
Application number: US310854A
Authority: US
Inventors: Frederick D Banning
Original assignee: MEMOVOX Inc
Current assignee: MEMOVOX Inc
Priority date: 1939-12-23
Filing date: 1939-12-23
Publication date: 1941-04-22
Anticipated expiration: 1958-04-22

Description

"April22,1941. ANNING 2,239,359

STYLUS HEAD MOUNTING Filed Dec. 23, 1939 2 Sheets-Sheet 1 VINVENTOK,

AT TOKNEY P Z F. D. BAN-NING 2,239,359

STYLUS HEAD MOUNTING Filed Dec. 23, 1939 z Sheets-Sheet 2 BY 'ATTOKNEY records (Sometimes called 'play back).

Patented Apr. 22, 1941 2,239,359 smUs asap MOUNTING Frederick D. Banning, Los Angeles, Calif., as-

:lgnor, by mesne assignments, to Memovox, Inc., Beverly Hills, cum, a corporation of Ohio Application December 2 3, 1939, Serial No. 310,854 7] Claims. (c1, sir-23) This invention relates to a mounting for a combination sound recorder and reproducer head.

In the phonograph art, it is frequently desirable to have a machine which can be used eitherfor making records (recording) or reproducing In such a dual purpose machine, it is common to use a combination stylus head, that is one that can be used either for recording or reproduction by appropriate changes in the connections of the amplifier with which the head is being used. This of course refers to an electrical head; if the head is purely mechanical, no amplifier is used.

In either case, when the head is used for reproduction, it must be free to follow variations in the record surface ina direction transverse permit the stylusto accuratelyfollow the record groove. vAlso a relatively light pressure is required on the stylus.

When the head is used for recording in accordance with the usual practice, free movement transverse to the recording surface is'still reand is attached to one end of an arm 6 mounted.

quired to allow the stylus to follow the record surface. On theother hand, since the stylus must now form the record groove, no lateral freedom between the carriage and the head is permissible, but the head must be advanced by the movement of the carriage. Further, the stylus must be urged against the record blank with a greater pressure.

It is of course also necessary to lift the stylus entirely off the record surface when it is desired to remove the record, or to adjust the stylus forward or backward relative to the record groove.

It is a principal object of this invention; to provide an improved mounting for a stylus head for optionally allowing the head lateral compliance for reproduction, locking the head against lateral compliance and increasing the weight or pressure on the stylus for recording, or lifting the head so that the stylus will be free of the record surface.

It is another object of this invention to provide such a mechanism comprising a simple unitary structure.

It is still another object of' this invention to provide such a mechanism which accomplishes its results without the use of springs.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of the invention. For this P p se there is shown a form in the drawinss accomfication. This form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in 8. limiting sense, since the scope of this invention is best defined by the appended claims.

In the drawings:

Figure 1 is an elevational view, largely diagrammatic, showing the improved mounting;

Figs. 2 and 3 are detail sections as seen on correspondingly numbered planes of Fig. -1;

Fig. 4 is aview similar to Fig. 1 showing analternate position of the parts; and

Fig. 5 is another view similar to Fig. 1 show- .ing a further alternate position of the parts.

Referring to the drawings, a combination -recording and reproducing head is indicated 'by 5,

o oarriage I. The carriage I is slidably supported on a guide rod 8, so arranged that movement of the carriage i along rod 8 will cause the stylus 8 carriedby head i to move across the surface of a record Ill in a well understood manner. Although the record It) is shown as of disc form, it is obvious that it could equally well be ofany other well known type, as for example, cylindrical.

, Carriage I is so arranged as to be capable of angular adjustment about its supporting bar 8 toany one of three positions, the arrangement beim such that in one position the arm 6 is ,I lifted so that stylus 9 is clear of record It; in

another position arm 6 is supported for universal movement with. respect to carriage I; while in the third position, arm 6 is confined to pivotal movement in one plane with respect to carriage I, and the fulcrum point is changed, so that a larger portion of the weight of arm 6 and'head 5 urges stylus 9 against the surface of record III.

Carriage I is shown as comprising a bell crank having an upwardly extending arm I2, and arm ll transverse thereto, these arms being joined to a hub I4 through which the guide rod 8 passes. Arm l2 has a platform l5 above arm I3,

and serving to support arm 6. The weight of these tends to rotate carriage I in a counterclockwise direction about'bar 8, this tendency being opposed by arm I3 engaging a cam I6. By

turning this cam I, as by a finger grip II, the

angular-position of carriage I about bar I may 1 and 2) respectively on opposite sides of the arm.

Each cheekhas a 8101; II flirpulh which a pin panying forming part of the present speci It in the upper end 2! of arm extends.

Arm 6 is free to swing universally on supporting pin I8, the vertical movement being restrained by the ends of slots 23 engaging pin 24, the lateral movement being limited by cheek 2! or 22 engaging the side of end of arm 12. This is the condition for reproduction or play back since the stylus isfree to follow vertical as well as lateral deviations of the record groove. The freedom of movement allowed is ample to take care of any irregularities in the record. The weight of head 5 and that part of arm 6 to the left of pivot I8 is partly counterbalanced by cheeks 2 l 22 and the part of arm 6 to the right of pivot It, so that will also rotate in that direction through a small angle, which will lower pin it and allow arm 6 to swing downward about the point of stylus 9, until a pair of pins 39 (Fig. 2) carried on platform l5 engage bosses 3i on arm 6 and pin It moves free of surface l9 (Fig. 4). These pins may have conical or pointed ends whichengage correspondingly shaped recesses in bosses 3!.

Arm 6 is now supported on stylus 9 and pins 30. Thus arm 6 is restrained against lateral movement but is still free to swing in a vertical plane, the pointed pins serving to accurately position arm 6 relative-to the carriage. This is the condition'for recording (see Fig.4) Further, the fulcrum point has been moved away from the head 5, thus there is less counterbalancing of the weight of head 5, etc., and the force urging the stylus against the record is materially increased.

It will be understood that in the recording as well as the reproducing conditions just described, the carriage l is moved so as to cause head 5 to travel across the record at thesame rate as the record groove. One means for accomplishing this is shown. Thus, a threaded rod 32 may be provided, this rod being driven by appropriate -mechanism with'respect to the record carrying mem-' ber 33; The pitch of the threads on rod 32 and the rate at which it is driven must of course be properly correlated to the speed of the record and thepitch of the sound groove, already on the record or being cut thereon.

Rod 32 is threadedly engaged by a feed nut 36 secured on a springarm which is attached to carriage I in any convenient manner as by screws 36. 'Theflex-ibilit'y of arm 35 permits carriage l to move counterclockwise around rod 8 to re- I cordingposition in response to movement of cam 16. This movement serves to increase the tension ofnut 34 against threaded rod 32, which is desirable when recording.

When it is desired to lift stylus 9 free from the record Ill, cam I6 is turned clockwise approximately 90" from the position of Fig. 1, this causing carriage to swing clockwise about its support 8 and raising pin 18. This will raise arm 6 about stylus 9 as a pivot until the lower end of slots 23 engages pin 24, after which arm 5 will swing with arm I, lifting stylus 9 fromthe record surface (see Fig. 5). At the same time, spring arm 35 will swing downwardly; moving nut 34 out of engagement with rod 32, so that carrie ge may be slid along rod 8 in either direction. An ad'- aesasso :lusting screw' 21 threadedly mounted in lug 28 on carriage 1 provides means for properly adiusting the tension of spring 35.

What is claimed is:

1. In a device of the character described, a stylus head, an arm for supporting said head, a carriage, meansforming a pair of bearing supports forthe arm, comprising sets of cooperating bearing-elements on the arm and on the carriage, said sets being at different distances from the head, and means for adjusting the carriage for causing either of the sets to be placed in cooperative relation.

2. In a device of the character described, a stylus head, an arm for supporting said head, a carriage, means forming a pair of bearing supports for the arm, comprising sets of cooperating bearing elements on the arm and on the carriage, said sets being at different distances from the head, and means for adjusting the carriage for causing either of the sets to be placed in cooperative relation, one of said sets comprising a ball and socket Joint, whereby the arm is allowed universal movement with respect to the carriage, the other set comprising'a pivot, whereby the arm is restricted to movement in a single plane with respect to the carriage.

3. In a device of the character described, an arm, a stylus head on said arm adapted to rest on a record, a carriage, means forming a pair of bearing supports for the arm, comprising sets of cooperating bearing elements on the arm and on the carriage, said sets being at different distances from the head, said arm extending from the head beyond said sets to provide a counterweight for the head,,and means for adjusting the carriage for causing either of the sets to be placed in cooperative relation, whereby the amount of counterweight acting on the head is altered. i

4. In a device of the character described, an arm, a stylus head on said arm adapted to rest on a record, a carriage, means forming a pair of bearing supports for the arm, comprising sets of cooperating bearing elements on the arm and on the carriage, said sets being at different distances from the head, said arm extending from i the head beyond said sets to provide a counterweight forthe head, and means for adjusting the carriage for causing either of the sets to be placed in cooperative relation, whereby the amount of counterweight acting on the head is altered, one of said sets comprising a ball and socket joint, the other set comprising a pivot, whereby the freedom of movement of the arm with respect to the carriage is altered at the same time as the counterweight effective on the head is altered.

5. In a device of the character described, an

arm carrying a stylus head adjacent one end, said head being adapted to rest on a record, a carriage, means forming a pair of bearing supports for the arm, comprising sets of cooperating bearing.