US1683670A - Phonograph - Google Patents

Description

Patented Sept. 11, 1928.

UNITEDIS'TATES PATENT, or

FICE'.

rsami'nosor, or reorder-KEN, JAPAN, ASSIGNOR or ONE-HALF r KAKUTARO r TAKEI, or TOKYO, JAPAN.

' PHONOGRAPH.

Y .lpplication'fll'ed February 18, 1925, Serial No. 10,078,. and in Japan Mai-ch13, 1924,

This invent-ionrelates to improvements in phonographs of thetype in which therevolution of the record disc is so controlled that the speed of apoint thereof registering with the point of the phonographic needle is kept constant, and has for its object certain improvements in phonographs of the type specified according to which the controlling of the speed isiefl'ected by means, simple in construction and sound in. operation.

According to the present invention a carriage is provided for the governor and the friction disc, which disc engages the underside of the turntable, and a track is provided upon which the carriage is adapted to move. A link member is provided forming a connection between the carriage and the tone arm, whereby the phonographic needle, as it traverses the record disc, causes the fr1ction disc to be moved across the underside of the turntable with and at a point immediately beneath the said needle.

In the accompanying drawings:

Fig. 1 is aside view of the phonograph partly in section. I Figure 2 is a side elevatlon perpendicular to that in Figure 1. p I

In a body rotating at a constant angular speed, the linearspeed of a polnt thereon a0 varies according to the radial distance of that point from the center of rotation, and

it is obvious that to obtain a constanthnear speed of a particular point varying 1ts radial distance, the angular speed must be suitably varied. For this reason, it will be readily understood that the angular or rotating speed of a record or a turntablemust be gradually changed ,or lncreased as a'phonographic needle passes across the record from i the outside towards the center of the record disc. 1

Referring now'to the drawing, a phonograph according to this invention comprises a casing 31, an ordinary sprlng motor a turntable spindle 1, driven by sald sprlng motor, a turntable 2 mounted thereon and 6 is slidably mounted on the track 4;.

facilitate the sliding motion of said carriage. a number oflantifriction balls 20 may be lnterposed between the underside of the carriage 6 and the track 4 in well known manner. The carriage 6 has two upward stands, in the upper-end ofone "stand being jou-rnalled a spindle 7. The spindle 7. has secured thereto a friction disc .8.

wheel 9. The friction. disc 8 engages the underside of the turntable 2 at the point immediately beneath the contact point of the phonographic needle on the record disc and it is driven by said turntable during operak Atthe other end of the spindle 7 is carried a toothed tion. This engaging contact is assured by b means of the spring 5. Between the two. stands of the carriage 6 a small shaft 10 is rotatably mounted. This shaft carries a toothed wheel 21 adapted to engage the toothed wheel 9 whereby theshaft 10 is rotated. ,The shaftlO serves as a governor shaft. The governor maybe of any type, but in the drawings is shown a centrifugal governor comprising a collar 11 fixed to the shaft 10, another collar 12 slidably mounted on the shaft, two spring blades-13 connecting the collars; which carry weights 14. The position of the slidable collar 12 is arrested in one direction by means of a brake pad 16 mounted on a stand 15.

l/Vhen the turntable 2 rotates,the friction disc 8 will be rotated at a linear rim speed equal to that of the record disc at the contact point of the needle on said record disc. The rotation of the friction disc 8 is controlled by the. governor above described, to rotate at a constant angular and consequently peripheral speed. The result will be that the linear gradually varies its position in accordance I with the centerward movement of the needle.

The carriage 6 is driven by the movement of the tone arm 17 through the link member 18 and always keepsthe friction disc 8 in contact with the underside of the turntable 2 at a point corresponding to the contact point of the needle 19Ton the record disc.

With a mechanism according to this invention it will be obvious that the linear speed at the point of contact of the needle 19 with the record discB is kept constant, independently of its radial distance, and a un form speed of the record disc can be assured.

Moreover, as the pointof the needle 19 and the engaging pointof the friction disc 8 with the underside ofthe turntable 2 are always kept in register it is possible to use a record disc of a larger diameter than with phonographs of the well-known type, as the pres-f sure of the needle is taken by the :friction discs." p P I Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is In a phonograph of thetype specified, a

tone arm, a rotatabletur'ntable, means for driving said turntable, a friction disc, :1. governor, a carriage adapted to carry said friction disc and said governor, a track for said carriage comprising a horizontally disposed plate hinged at one end and being supported at .tlieiother end bymeans of a spring whereby the friction disc is pressed against the 'under side of the turntable anda link me1nber connecting said tone arm and said carriage whereby the carriage is moved by the phonographic needle as the latter traverses the record disc thereby causing the friction disc to be moved across the under side of the turntable with and at a point immediately beneath the needle.

In testimony whereof I afiix my signature.

ISAMU HOSOI.

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