IMPROVE- MENTS IN PIANOFORTES
Year: 1857

page_text: LETTERS PATENT to George Crawford, of Edinburgh, in the County of
Mid Lothian, North Britain, Music Seller, for the Invention of "IMPROVE-
MENTS IN PIANOFORTES."
Sealed the 3rd September 1857, and dated the 14th May 1857.
PROVISIONAL SPECIFICATION left by the said George Crawford at the
Office of the Commissioners of Patents, with his Petition, on the
14th May 1857.
I, GEORGE CRAWFORD, of Edinburgh, in the County of Mid Lothian, North
Britain, Music Seller, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PIANOFORTES," to be as follows, that is to say:-
This Invention relates to various modifications of the details of pianofortes,
for the purpose of producing a general improvement in the tone and effect of
the instrument.
According to one portion of these improvements, the part of the pianoforte
technically known as the "rest bridge" is made of glass, so as to secure a
superior purity of tone. The sounding board has upon it a double bridge
with a suspension tube, the bridge being indented with bone or ivory instead
of small pins in order to conduct more tone or vibration from the sounding
board. The suspension tube is screwed to the sounding board between the

page_text: two bridges, for the strings to pass underneath, causing a transverse bearing,
which takes the strain from the sounding board and allows of a free
vibration.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Crawford in the. Great Seal Patent Office on the
13th November 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
CRAWFORD, of Edinburgh, in the County of Mid Lothian, North Britain,
Music Seller, send greeting.
The
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of May, in the year of our
Lord One thousand eight hundred and fifty-seven, in the twentieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
.me, the said George Crawford, Her special license that I, the said George
Crawford, my executors, administrators, and assigns, or such others as I, the
said George Crawford, my executors, administrators, or 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 "IMPROVEMENTS IN
PIANOFORTES," upon the condition (amongst others) that I, the said George
Crawford, by an instrument in writing under my hand and seal, should par-
ticularly 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.
1
declare the
NOW KNOW YE, that I, the said George Crawford, do hereby
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
in writing, reference being had to the accompanying Drawings, and to the
letters and figures, marked thereon, that is to say:-..
My said, Invention relates to various modifications of the details of piano-
fortes, for the purpose of producing a general improvement in the tone and
effect of the instrument.
According to one portion of these improvements, the part of the pianoforte
technically known as the "rest bridge" is made, of glass, so as to secure a

page_text: superior purity of tone. The sounding board has upon it a double bridge
with a suspension tube, the bridge being indented with bone or ivory instead
of small pins in order to conduct more tone or vibration from the sounding
board. The suspension tube, if screwed to the sounding board between the
two bridges for the string to pass underneath, causing à transverse bearing;
which takes the strain from the sounding board and allows of a free vibration.
And in order that my said Invention may be properly understood; I shall now
proceed to describe the several illustrative Figures on the explanatory Sheet of
Drawings which I have hereunto appended for the purpose of showing certain
modifications under which my improvements may be judiciously carried out in
práctice.
Figure 1 on my accompanying. Sheet of Drawings is a sectional elevation of
the internal portion of a pianoforte, showing the sounding board and "rest" as
arranged with one modification of my improvements applied thereto; Figure 2
is a transverse vertical section, taken at right angles to Figure 1; and Figure 3
is a vertical section of a portion of the details, drawn to a larger scale than
Figures 1 and 2, to show more clearly the arrangement of the tubulär bridge
herein-after described.
1
"
The first part of my said Invention has reference to what is technically
known as the "rest bridge" in this modification this part of the instrument is
constructed of glass, or other material more résonant than wood, or a coni-
bination of wood and metal, which materials have hitherto been used for.the
purpose. The improved "rest bridge," as shown in my illustrative Drawing;
is made of a series of pieces of glass, the upper surface of which, or that upon
which the strings rest, being either of a convex or concave form, or it may bé
made with a flattened ridge, and sloping or angular sides. The several pieces
of glass intended to form the "rest bridge" are placed on the rest plank 'A;
and the pieces of glass B are arranged or placed end to end; and curved or
otherwise disposed so as to form the figure required for the support of the
strings, as they vary in length, and are held in position by the downward
pressure of the strings. The strings of the instrument pass in the first place
from their "hitch" pins C, beneath the tubular bridge D, which is fastened to
a wooden stay at the back of the sounding board E. The details of this
bridge are more clearly shown in the enlarged sectional view, Figure 3: It
consists in this modification of the duplex pieces of wood D, in which are
inserted pieces of bone or ivory F; these pieces of ivory are either notched or
plain, and receive the strings G, which rest partly upon the ivory and partly
on the bridge D. The strings are passed over the first series of the pieces. F;
and under the tube II; this tube is secured to the sounding board by screws 'I,

page_text: which pass through the sounding board E, and into a strengthening piece of
hard wood J, at the back of the sounding board. A modification of the arrange-
ment of this part of the improvements is obtained by making the bridge D in
one piece instead of in two, as shown in the sectional view, Figure 3, the
tube H being fitted in a hollow or indentation in the bridge. The strings G.
pass under the tube H, and over the second series of ivory supports F, whence
they are carried over the rest bridge B, beyond which they are passed through
studs K, and are finally secured to the rest pins L. Instead of making the
rest bridge of glass, as herein-before described, it may be constructed of china,
earthenware, particular kinds of stone, porcelain, or other vitrified substances,
or other suitable materials more resonant than wood, or a combination of wood
and metal.
Another modification of my improvements consists in the use and applica-
tion of double sounding boards in pianofortes, in order to increase the volume
of sound from the instrument. The rest plank above the duplex sounding.
boards may be supported by means of metal tubes, fitted between the two
sounding boards, and wooden bracings may be fitted behind the sounding
boards to support the "rest plank." Pianofortes made according to these
improvements possess great brilliancy of tone, and give out a volume of sound
greatly superior to those of the ordinary construction; this superiority of tone
and power being derived from the use of the crystal or other similar resonant
body, and from the strain being removed from the sounding board. by the
transverse bearing obtained by the suspension tube.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent is,―
First, the general arrangement and construction of pianofortes, as herein-
before described.
Second, the use and application of glass, china, earthenware, stone, or
composition of a generally similar character in the manufacture or construction
of "rest bridges" for pianofortes, as herein-before described.
Third, the use and application of metal tubes to the bridges of pianofortes,
in which arrangement the strings are supported upon pieces of ivory, bone, or
other suitable material forming the apices of the bridge, the combination of

page_text: the parts tending to take the strain off the sounding board, and increasing the
vibration of the instrument, as herein-before described.
Fourth, the use and application in pianofortes of a secondary sounding board,
in order to increase the volume of sound imparted by the instrument, as
herein-before described.
In witness whereof, I, the said George Crawford, have hereunto set my
hand and seal, this Tenth day of November, One thousand eight
hundred and fifty-seven.
GEORGE CRAWFORD. (L.S.)