US1386892A

US1386892A - Edward p

Info

Publication number: US1386892A
Authority: US
Publication date: 1921-08-09
Anticipated expiration: 1938-08-09

Description

E. P. MFFITT.

PHONOGRAPH.

0N FILED INVENTOR. EDWARD P. MOF'FITT ATTORNEY UNITED `STATES EDWARD P. MOFFITT, OF MINNEAPOLIS, MINNESOTA.

IPI-IONOGRAPH.

i ,season Specification of Letters Patent.

Patented A110. 9, 1921.

Application filed March 15, 1920. Serial No. 365,908.

To @ZZ fui/Lomi t may concern.'

Be it known that l, EDWARD P. Morrrr'r, a citizen or the United States, residing at ll'linneapolis, in the county ot Hennepin and State or Minnesota, have invented certain new and useiul Improvements in Phonographs, oi which the following is a specication.

My invention relates to improvements in sound reproducing devices Afor phonographs, and the main object is to provide'means whereby the direction oftlie sound reproducing Aneedle or stylus'will at all times be maintained in a tangential position to the record groove in which it is engaged. Further objects will be disclosed in the course ot the speciiication and inthe accompanying drawing, in which;

VFigiue 1 is a top view ot aphonograph equipped with niy invention.

2 is a sectional view on the line 2 2 in Fig. 1. l

3 is a top view of a phonograph equipped with a niodiliedtorin of my device. v

Fig. 4 is a sectional view on the line 4-4 in llig; 3. f

llig. 5 is an enlarged detail side view oi the sound box- 9 as seen troni the right in Fig. 4.

Referring to the drawing'by reterence'numei-als.,v 6 designates a phonograph ot the well known type in which is played the disk style ot record, therecord 7 being revolved on a turntable 8. lt has been customary heretofore to mount the sound box 9 to the tone erin 10 so that when a record is being play-ed. the stylus, in its path across the record always retains a relatively radial direction to the are which the needle describes when the tone arm ltlswings on its center. lt is known howeverthat a more scientifically correct reproduction of. the sounds originally recorded on the record may be had it the directionot the stylus is maintained in a tangential relation to the record groove it engages.

To provide simple, practical and efficient means for thus retaining the proper position of the stylus secure the sound box 9 to a downward extension 12 of the tone arm 10, said extension havin@ a vertical pivot oint 13 so that the sound boX may swing vertically from a point 14. To the lower part et the eXtension`12 I secure a rod 15 having a socket 16 at the outer end thereof.

Vand 18. The distance between the centers of the balls is substantially the saine as the distance between the

centers

11 and 14, and the distance between the socket 16 and the center 14 is substantially twice as great as .the dist-ance between the socket 18 and the center 11.

`Wit-h the above described construction and proportions the rod 15 will always assume a position substantially parallel to a line between the stylus point and the center of the record. ln the present showing this position happens to be that of a radius of the record as the

centers

14 and 16 are in the same vertical plane as the stylus point. It may be stated, however, that this parallel .-relation will also occur even it' the stylus peint is not in the same vertical plane with the centersy 14 and 16, provided of course that said point will describe an are or curve vthrough the center of the record. And as the forward direction of the stylus is at all times perpendicular to a vertical plane through

centers

14 and 16, it must also be perpendicular to the` record radii and is consequently ltangential to the record groove in which the stylus point engages.

ln the modifications shown in Figs. 3 and 4 the distances between the points 14 Aand 16 and between the

points

11 and 18 4have been proportionately decreased making it necessary to provide a curved portion 2O in the rodi19 so that the latter will not stop against the vertical portion ot' the tone arm 10 until the stylus is clear of the turntable 8.

The joint 13, the universal connection 16 and the tone arm joint 21 allow the sound box to be lifted up so that needles and reoords can be changed when so desired.

"l am aware of the many previous attempts which have been made to overcome the objectionable feature of having the stylus point diagonally into the record groove, such for instance as by offsetting the sound boX on the tone arm, or using a rod parallel to the tone arm for actuating the sound box,

and of offsetting the swinging center of the tone arm, and a host of other devices, but in no instance have l seen a practical device for uniformly controlling the direction of the needle, as above set forth.

It is understood that theabove combinations and construction can be used in a variety of modifications of form and structure if within the scope of the appended claims.

Having now therefore fully shown and describedmy invention what l claim to be new and desire to protect 'by Letters Patent is:

l. in combination in a phonograph having a tone arm adapted to swing in an arc over a disk record, a sound box having a ystylus adapted to engage the record, said sound box being secured on a vertical pivot joint to said tone arm, and an actuating mechanism operatively connecting said sound box to a stationary part of the phonograph7 said mechanism being adapted to change 'the direction .of the sound box relative to the tone arm so that the direction of 'the stylus will be perpendicular to a line through it and the record center at all times while the stylus engages the record.

2. ln combination in a phonograph having a tone arm adapted to Swingin an arc over a diskrecord having grooves therein, al sound box having a stylus-adapted to engage said grooves, said sound box being secured to said tone arm on a vertical pivot, and means for causing the direction of the stylus to beconstantly retained in tangential relation'to the groove engaged, said means consisting of an actuating mechanism operatively connecting said sound box to a rigid part of the phonograph. n

3; Vln combination in a phonograph having a ltone larm adapted to swing in an arc over a. disk record, a sound box secured on a vertical axis to the free end of saidV tone arm and having a stylus adapted'to engage the record, and anaetuating arm pivotally connected at one end to a fixed axis near the swinging center of the tone arm, the otherend of said Vactuating arm being` rpivotally secured to said sound .box at-a vdistance lfrom said vertical axis of approximately twice the distance between the fixed axis and the swinging center of the tone arm.

4. In combination'in a phonograph having a tone arm adapted to swing in an arc over a disk record, a sound box secured on a vertical axis to the free end of said tone arm and having a stylus adapted to engage the record, and an actuating arm pivotally connected at oneend to a fixed axis near the swinging center of the t0n-e arm, so that a line through the .fixed axis and the said tone arm center will be perpendicular to a line through said center and the center of the record, the other end of said actuating arm being Pivotally secured to said sound box at a distance from said vertical axis of approximately twice the distance between the fixed axis and the swinging center of the tone arm. l Y

5. In combination in a phonograph having a tone arm adapted to swing in an arc over a disk record, a sound box mounted on a vertical axis on the tone arm, the same having a stylus adapted to engage the record, and an actuating arm pivotally connected at one end to a fixed axis near the swinging center ofthe tone arm, the other end being pivotally connected to the outer end of' a projecting arm of the sound box, said actuating arm assuming a diagonal relation in respect to the tone arm, the distance between the vertical axis and the outer `-end 'of the projecting arm .being substantially twice that between the fixed axis and the'swinging center of the tone arm.

6. In combination in a phonograph having a tone arm adapted to Swingin an arc over a disk record, a sound box mounted on a vertical axis on the tone arm7 the same *ham/'ing al stylus adapted to engage the record, and an actuating arm pivotally conlength of the actuating arm being substantially the same as the distance between the swinging' center of theY tone arm and the vertical axis supporting the sound'box.

In testimony whereof l afixmy signature.

EDWARD P. MOFFITT. Y