IMPROVEMENTS IN PIANOFORTES
Year: 1861

page_text: LETTERS PATENT to William Porter Dreaper, of 56, Bold Street, Liver-
pool, for the Invention of "IMPROVEMENTS IN PIANOFORTES."
Sealed the 12th November 1861, and dated the 21st May 1861.
PROVISIONAL SPECIFICATION left by the said William Porter Dreaper
at the Office of the Commissioners of Patents, with his Petition, on the
21st May 1861.
I, WILLIAM PORTER DREAPER, of 56, Bold Street, Liverpool, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN PIANOFORTES," to
bo as follows:-
This Invention has for its object improvements in pianofortes. For these
purposes a tie rod is applied to one or more of the bars of the sound board of
pianoforte in such manner as to tend to draw such bar or bars into a bent
form; provision is made by means of screw nuts to apply any degree of tension
by means of such tie rod to the bar to which it is applied. On the bar of the
sound board are fixed two brackets or projections at a distance the one from
the other, and by preference these brackets or projections should be equidistant
from the bridge. The tie rod is passed through these brackets or projections,
and on one or both of the ends of the rod a screw is formed to receive a screw
nut so as to obtain the desired degree of tension. In some cases I apply a
spring between the screw nut and the bracket or projection, by which the
strain is rendered elastic.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Porter Dreaper. in the Great Seal Patent Office on
the 21st November 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
PORTER DREAPER, of 56, Bold Street, Liverpool, send greeting.
WHEREAS Her most. Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of May, in the year of our Lord One
thousand eight hundred and sixty-one, in the twenty-fourth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Porter Dreaper, Her special licence that I, the said William Porter
Dreaper, my executors, administrators, and assigns, or such others as I, the
said William Porter Dreaper, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN PIANOFORTES," upon the condition (amongst others) that I, the said
William Porter Dreaper, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
'date of the said Letters Patent.
NOW KNOW YE, that I, the said William Porter Dreaper, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
This Invention has for its object improvements in pianofortes. For these
purposes a tie rod is applied to one or more of the bars of the sound board of
a pianoforte in such manner as to tend to draw such bar or bars into a bent
form; provision is made by means of screw nuts to apply any degree of tension
by means of such tie rod to the bar to which it is applied. On the bar of the
sound board are fixed two brackets or projections at a distance the one from
the other, and by preference these brackets or projections should be equidistant
from the bridge. The tie rod is passed through these brackets or projections,
and on one or both of the ends of the rod a screw is formed to receive a screw
nut so as to obtain the desired degree of tension. In some cases I apply a

page_text: spring between the screw nut and. the bracket or projection, by which the
strain is rendered elastic.
And in order that my said Invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 represents a section of an ordinary cottage or upright pianoforte,
but it will be evident that my improvements are also applicable to other
pianofortes.
A, the wrest plank; B, the tone or sound board; C, one of a series of bars
glued to the back of tone or sound board for the purpose of strengthening it
to resist the down pressure of the strings resting on the bridge on the front of
the same; D, D, are metal brackets or tone generators, made by preference
of spring steel (though other material may be used); a plan of one of them is
shewn in Figure 2; they are each attached by two screws or other convenient
means to the bar C of the tone board, and they are applied near each extremity
of the same; E is a rod of steel wire or other suitable material passing from
the head D' of one of the tone generators to the head of the opposite tone
generator at each end of the rod; E are screws, which have screw nuts thereon
to obtain tension; F is a strong spiral spring (which is preferred to be used,
but is not essential) interposed between the head D of one of the tone gene-
rators and the corresponding nut F. When the screw nuts are tightened the
rod E pulls forward the top arm of each of the tone generators and forces the
bar to which they are attached into a curved line, thereby causing the tone or
sound board to become convex on the side to which the strings are attached,
and it is thus held in a state of tension, the strain, however, being rendered
elastic by the spring. The tone board can be strengthened as may be required
by screwing up the nuts at each end; thus, instead of its being supported only
by glued wooden bars as heretofore, my arrangement adds to it an elastic
metallic support which gives great freedom and volume of tone to the instru-
ment. I generally apply my Invention to the centre of the tone board, where,
(the bridge being at or near its centre), it is most affected by the down
pressure of the strings; but the apparatus may be applied to any part of the
tone board requiring an elastic support. In Figure 3 one of the tone gene-
rators is shown made of hard wood. In applying the tone generators above
described to one or more of the bars near the centre of the tone board I have
found that the two adjacent bars, or more especially the next bar in the direc-
tion of the treble, requires support to render the tone of the instrument uniform

page_text: and even; for this purpose. I employ apparatus such as is shown at Figure 4;
this apparatus is composed of a piece of beech or other hard wood a, about of
an inch thick, about 1 inch wide, and of any length required; it has two
blocks b, b, one of which rests on the tone board bar C, near to the end
thereof, and the other nearly at the back of the bridge; c is a screw attaching
the apparatus to the bar to which it is applied; and d is a spiral spring inter-
posed between a button placed around the head of the screw and the piece a.
By tightening the screw the piece a may be forced against the bar to which it
is applied with any required degree of force, the spring, when used, however,
giving elasticity to the pressure. This arrangement adds an elastic strength
to the tone bar, and tends to improve and equalize the tone where it may bo
required.
Having thus described the nature of my Invention, and the manner of per-
forming the same, I would have it understood that I do not confine myself to
the exact details described; but what I claim is the application of the rods E
to the bars C of the tone boards, so as to draw the bar and the tone board
connected théréwith into a convex form, as herein described.
-
In witness whereof, I, the said William Porter Dreaper, have hereunto
set my hand and seal, this Thirtieth day of October, in the year of our
Lord One thousand eight hundred and sixty-one.
W. P. DREAPER. (L.S.)