US760606A - Record-plate for gramophones. - Google Patents

Description

PATENTED MAY 24,1904; T. B.BI;RNBAUM1 k RECORD PLATE FOR GRAMOPHONES.

Patented May 24, 1904.

PATENT OFFICE.

THEODORE B. BIRNBAUM, OF BERLIN, GERMANY.

RECORD-PLATE FOR GRAMOPHO NES SPECIFICATION forming part of Letters Patent No. 760,606, dated May 24, 1904. Application filed December 24,1900. Serial No". 40,947. 1N0 modell) I To all whom it may concern:

Be it known that I, THEODORE B. BIRNBAUM, managing director, a subject of the Queen of Great Britain and Ireland, residing at 36 Ritterstrasse, in the city of Berlin, in the German Empire, have invented certain new and useful Improvements in Record-Plates for Gramophones, of which the following isa specification.

The record-plates for gramophones are made of circular disks of hard rubber or similar material of about one-tenth inch thickness.

These plates ortablets are, as a rule, fitted with an aperture for the reception of the rotating shaft when the gramophone is placed Upon the surface of the record-tablet the phonographic record-line is engraved, forming a spiral-like groove, serving to guide the gramophone-needle which is connected to the sounding-drum. Upon the rotation of the record-tablet the needle moves in the spiral-like groove from the edge of the tablet to the center thereof, corresponding to. the configuration and the extent of the said.

spiral groove. The commencing point of the record-line is accordingly arranged near the periphery of the tablet about one-fifth of an inch from its outer edge. With this form of arrangement of gramophone record-tablets it is a great inconvenience that it requres a certain amount of skill to introduce the needle into the outer extremity of the record-line, a very serious drawback, which is especially troublesome if short-sighted persons want to make use of the gramophone. Furthermore, it frequently happens, unless great care is taken in positioning the needle upon the record-tablet, that the needle glides off the edge of the said tablet and strikes against the driving-gear of the contrivance, whereby the neewhi ch projects about one twenty-fifth to onetenth of an inch upon the upper surface of the said tablet. The spirally-wound recordline is so arranged upon the record-tablet as to start directly at the projecting edge I) or in the proximity thereof. To start the gramophone, it is only necessary toplace the point of the needle close to the projecting rim 6 of the plate (0. Thus it is possible to operate the gramophone even in a dark room and without the necessity of special skillor experience in handling, inasmuch as the touch will afford a sufiicient guide to the operator for the adjustment of the needle upon the gramophone-tablet in the proper position for actuating the apparatus. The projecting rim presents the further advantage of a far more eflicient ,protection'against' injury from exterior influences of the upper part of the tablet, which contains the spirally-wound recordline. If a number of record-tablets construct ed according to my invention are placed on top of each other, the tablet bearing the rec.- ord-groove is not touched at all by the upper tablet in view of the latter resting upon the rim 6 of the lower tablet or plate Then the thick edge affords a greater security against breakage, and thus renders the tablet more durable.

What I claim, and desire to secure by Letters Patent of the United States, is-

A flat gramophone-plate provided with an integral annular rim projecting above its record-surface atthe extreme outer edge of the platev and the said surface having a spirallyarranged record-line formed therein,said line beginning close to the inner side of said rim and terminating at a point remote from the rim near the center, said rim being adapted to guide the gramophone-needle into'the beginning of the record-line, substantially as set forth.

In witness whereof I have hereunto signed my. name in the presence of two subscribing Witnesses.

THEODORE B. BIRNBAUM.

Witnesses:

HENRY HASPER, VVoLDEMAR HAU'P'I.

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