US57743A - Improvement in metal frames for pianos - Google Patents

Description

FFTGE.

MARTIN MARTINS, OF NEY YORK, N. Y.

IMPROVEMEN'l IN METAL FRAMES FOR PIANOS.

Specification forming part of Letters Patent No. 57,743, dated September 4, 1865.

To all whom t may concern.-

Be it known that I, MARTIN MARTINS, of the city, county, and State of New Yor'k, have invented a new and useful'Improvement in Metal Frames for Piano-Fortes; and I do hereby declare that the following' is afull, clear, and exact description thereof, which willenable others skilled in the art to make and use the same, reference being' had to the accompanying drawings, forming part of this specification, in whioh- Figure l represents an inverted plan of this invention. Fig. 2 is a longitudinal section of the same.

Similar letters of reference indicate like parts.

This invention relates to certain improvements in the metal case of piano-fortes, said case being cast solid, with a series of longitudinal and of cross-braces, in combination with tension-screws extending under the metal frame in a direction parallel with the strings, or nearly so, and rendered yielding and adjustable by suitable springs in such a manner that, by said tension-screws and adjustingsprings, the strain of the strings is counteracted, and the metal frame is held i'iat and prevented from bulging ont when exposed to a variable temperature, or by the continuous strain of the strings. the tension-screws is regulated by the springs, which can be compressed more or less, simply by screwing the nuts in or out.

A represents a metal frame, cast of iron or any other suitable material, and provided on its upper or front surface with a series of longitudinal, or transverse braces or rafters, a, which extend across the frame from one rim of the same to the other, and which serve to strengthen the frame and to render it capable of sustaining the strain of the strings. One end of the frame is provided with a doubleshouldered bracket, b, which is intended to support the wrest-plank c. Said wrest-plank is secured to the`-bracket b by screws or any other suitable means, and it is provided with a series of sockets to receive the tuning-pins g. From the tuning-pins the strings extend The strain exerted by over suitable bridges to the hitch-pins d in the usual manner, and the bridges rise from the soundingboard, and they are supported by suitable studs, whereby the same are elevated far enough to let the braces or rafters a pass through under them. The hitch-pins are secured in a metal plate, df, which is fastened to the frame A. From the lower or rear surface of the frame A project two lips, cf, and between these ribs the sounding-board s is introduced, as clearly shown in the drawings. This sounding-board is supported by pins or anyother suitable means, and the metalfranie Ais strengthened by a series of screw-rods, h, which extend on its rear side or lower surface parallel with the strings, or nearly so, as shown in Fi g. l of the drawings. These screws have their bearings at 011e end in the lip fof the frame A, and at the opposite end is an L- shaped plank, i, which is secured to the rear or lower surface of the bracket l), which supports the wrest-plank.

Suitable slots in the L-shaped plank z' serve to admit the screws, the ends of which extend through springs j, which bear at one end each against a stud, 7c, and at the other against the L-shaped plank t', as clearly sho wn in the drawings. By tightening the nuts l, which are f1tted on the screws on the end of rods h, the springs are strained, and a yielding strain is exerted on the metal frame A, which strain can be increased or diminished at will. By this strain the tendency of the metal frame to bulge out or to curve by the strain of the strings is counteracted, and a piano-forte with ametal frame is obtained, which will keep its tune for a long time 5 whereas piano-fortes with metal frames constructed in the ordinary manner are liable to get out of tune by the variations of the temperature, whereby the metal frame is caused to expand and to curve or bulge out under the increased strain of the strings.

l do not wish to confine myself, in carrying out my invention, to the preciseform of springs shown in the drawings, since springs of any desired form or shape may be applied, and if one spring is not sucient under each nut, two

or more springs muy be combined until thel desired effect is produced.

Having thus described myinventiomwliatl claim as new, and desire to secure by Letters Patent, is-

1. The tension screw-rods h and springs j, in combination with the frame A, constructed sind operating substantially its and for the purpose described.

2. The L-shaped plank i, in combination with the lips ef of the frame A, and with the tension screwrods h, constructed and opereting substantially as and for the purpose described.

MARTIN MARTINS.

Witnesses:

W M. DEAN OVERELL, M. M. LIVINGSTON.

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