IMPROVEMENTS IN PIANOFORTES
Year: 1858

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION .left by. William Spencer Driggs at the
Office of the Commissioners of Patents, with his Petition; on the 2nd
. March 1858. A communication from Spencer Bartholomew Driggs, of
.New York, in the United States of America.
I, WILLIAM SPENCER DRIGGS, of New York, but now -residing at Berners
Street, in the County of Middlesex, Gentleman, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN PIANOFORTES," to be as follows:-*
This Invention relates to improvements upon a Patent obtained on behalf of
the present Inventor, and bearing date the 1st day of November 1855.
The Specification of that Patent described among other matters a mode of
giving increased-resonance to pianofortes by the use of a double sound. board,
the second or additional sound board taking the place of the stiff planking
which formed the bottom or the back of the pianoforte case, and being
attached to the wooden side pieces of a skeleton metallic frame detachable
from the case, and carrying the wrest plank and the hitch plate, and con-
sequently taking the pull of the strings.
Now, the objects of the present improvements are to leave the sound
chamber, (the space between the sound board and the thin vibrating bottom
board,) as described in the said Specification, more free from obstruction, and
still further to improve the tone and simplify and cheapen the construction of
the instruments, and to materially reduce their weight.
These-results-are-attained by dispensing-with-the-main-and-heavier parts of

page_text: the wood framing, and bringing the framework and bracings which sustain
the pull of the strings, and which are to be made in a compact and efficient
form, as near to the strings as is practicable. This sustaining power consists of
metallic framing placed either wholly on one side or the other of the sound
board, or partly on one side and partly on the other, according to the kind of
instrument to which it is to be applied, or the taste or judgment of the maker,
and still further by securing the thin vibrating board which forms one side of
the sound chamber and the only back or bottom of the instrument directly to
the outer case of the instrument, giving it a slightly outward convex form to
increase its reverberating power; in order to give it a secure fastening the
bottom board of the sound chamber may be attached to strips of wood glued
on the inner side of the case, or to a light inside wood frame, as may be
required by the kind of instrument. When this board is applied to grand or
semi-grand pianofortes, it is preferable to extend it forward only to the lyre
In squares, uprights, and cabinets, and those of like form, it should extend
over the whole of the underneath or back surface of the instrument to get as
great. a reverberating surface as possible..
The sound board (proper) is to be attached directly to the inner sides of the
case, where the formation of the instrument will admit of it, or partly to them
and partly to light iron or wood frames, plates, or strips, where the complete
attachment to the case is not admissible. The sound board is connected to
the under or back vibrating board by one, two, or more sound posts, to ensure
sympathetic action.
These improvements when combined constitute a structure more nearly
resembling the body of a violin or violincello than has hitherto been attained
in the pianoforte, producing that full round tone, at once pure and sympathetic,
which has heretofore been peculiar to instruments of the viol kind.
It will be understood that this mode of applying a reverberating board as
an under or back sound board, is applicable to pianofortes of all kinds, whether
constructed of metallic or other framing, but for ensuring purity of tone and
sustaining power, it is desirable to keep the sound chamber as free from
encumbrances as possible.