IMPROVEMENTS IN THE CONSTRUCTION OF PIANOFORTES
Year: 1867

page_text: LETTERS PATENT to James Gilmour, of Glasgow, in the County of
Lanark, North Britain, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF PIANOFORTES."
Sealed the 21st April 1868, and dated the 1st November 1867.
PROVISIONAL SPECIFICATION left by the said James Gilmour at the
Office of the Commissioners of Patents, with his Petition, on the
1st November 1867.
I, JAMES GILMOUR, of Glasgow, in the County of Lanark, North Britain,
do hereby declare the nature of the said Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF PIANOFORTES," to be as follows, that is to say :-
This Invention, which relates to improvements in pianofortes, consists, in
the first place, of a means for resisting or counterbalancing the strain of the
strings or wires upon the framing to which these are attached. The counter-
balancing arrangement substantially consists either of a plate the full length
of the frame or beam known as the pin blocks, into which the screws and
hooks for tightening the wires are placed; or in place of a continuous plate
several strips, bars, or small plates may be fixed on to the upper and lower
pin blocks, and at the outer end of the plates strips or bars, eyes or hooks, are
placed, to which are again attached screw couplings. These arrangements

page_text: are situated on that side of the framing opposite that to which the strings are
applied, so that by tightening or loosening the screw couplings the whole
frame may be very effectually balanced to resist the tension of the strings in
place of having the strain all on one side as at present. The double strain
produced by this arrangement is maintained constantly in a perpendicular
direction on the upright post to which the pin blocks are attached; thus by
providing resistance to the tension of the strings by means of opposed bracing
the perpendicular and pin blocks can be made of much less scantling than at
present.
In connection with this Invention a hollow or belly-shaped sound board is
used resting against a wooden partition fixed in front of the frame carrying
the strings, the sound board being supported by sound pins or posts similar to
those used in violins, and having openings of suitable shape cut in it to
facilitate the reverberation of the sounds of the strings. The sound board
may be fixed by means of ligatures, or by the pressure produced through the
tension of the strings, thus imparting great freedom of vibration, which com-
bined with the hollow formed by the back partition affords additional power
to the tone, at the same time adding to its quality. The mode of counter-
balancing the strain, berein-before described, has the advantage of enabling
the uprights to be made wholly of iron or iron tubes of a light and, if desired,
ornamental character, such construction being suitable for hot climates where
the temperature greatly affects timber. Another mode of equalizing the
strain is by carrying the strings round the bottom of the frame or case and
fixing them on pins immediately at the back of the front ones, so that when
the pressure is applied to the front it naturaly finds its level by imparting the
strain to the back as well, but as the extra length of string diminishes the
strength a stronger or thicker string may be used for the back portion.
The second part of this Invention relates to the tuning of pianofortes; and,
in order to gain complete accuracy, in this respect, and at the same time
rigidity of tension, there are applied to the top. of the plate bars, or strips
which act as a compensating. lever, or levers a series of metallic strips hinged
at the rear end, and having a hook or, hole at the front end to which the
strings are attached. At a short distance, from the front end a screw passes
through each hinged. plate or. strip, the, point pressing on, the pin, block,, so
that as the screw is tightened or released the pitch of the string is at once
regulated,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Gilmour in the Great Seal Patent Office on the
30th April 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
GILMOUR, of Glasgow, in the County of Lanark, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of November, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her reign,
did for Herself, Her heirs and successors, give and grant unto me, the said
James Gilmour, Her special license that I, the said James Gilmour, my
executors, administrators, and assigns, or such others as I, the said James
Gilmour, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and 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
THE CON-
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
STRUCTION OF PIANOFORTES," upon the condition (amongst others) that I, the
said James Gilmour, by an instrument in writing under my hand and seal,
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 James Gilmour, do hereby declare
the 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, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is-to-say-
My said Invention, which relates to improvements in the construction of
pianofortes, consists, in the first place, of a means for resisting or counter-
balancing the great strain of the strings or wires upon the framing to which
these are attached. The counterbalancing arrangement substantially consists
either of a plate the full length of the frame or beam, known as the "pin
block" or "rest block," into which the tuning pins or screws for tightening
the wires are placed; or in place of a continuous plate several strips, bars, or
small plates may be fixed on the upper and lower pin blocks, and at the
outer or back end of these plates, strips, or bars eyes or hooks are placed, to

page_text: which are again attached metallic rods with screw couplings. These arrange-
ments are situated on that side of the framing opposite that to which the
strings are applied, so that by tightening or loosening the screw couplings the
whole frame may be very effectually balanced so as to resist the tension of
the strings. In place of having the strain all on one side, as at present, the
double strain produced by this arrangement is maintained constantly in a
perpendicular direction on the upright posts, technically termed the bracings,
to which the pin blocks are attached; thus by providing resistance to the
tension of the strings by means of an opposing strain the perpendicular
bracings and supporting posts can be made of much less "scantling" than as
present.
In connection with this Invention a hollow or belly-shaped sound board
may be used resting against a wooden partition fixed in front of the bracings
or upright posts, the sound board being supported by a rim and sound pins or
posts similar to those used in violins, and having openings of suitable shape
cut in it to facilitate the reverberation of the sounds of the strings. The
sound board may be fixed by means of ligatures or by the pressure produced
through the tension of the strings or by other convenient means, thus
imparting great freedom of vibration, which combined with the hollow formed
by the back partition, affords additional power to the tone, at the same time
adding to its quality. The mode of counterbalancing the strain, herein-before
described, has the advantage of enabling the uprights and rest plates or the
pin blocks to be made wholly of iron, or the former of iron tubes, of a light,
and, if desired, ornamental character, such construction being suitable for hot
climates where the temperature greatly affects timber. Another mode of
equalizing the strain is by carrying the strings round the bottom of the frame
or case and fixing them on pins immediately at the back of the front ones, so
that when the pressure is applied to the front it naturaly finds its level by
imparting the strain to the back as well, but as the extra length of string
diminishes the strength a stronger or thicker string should be used for the
back portion.
The second part of this Invention relates to the tuning of pianofortes; and in
order to gain complete accuracy in this respect, and at the same time rigidity of
tension, there are applied on the top of the pin block (which may be made either
of wood or iron) bars, slips, or strips, bars, slips, or strips, having a hook or hole
at the front end to which the strings are attached. At a short distance from the
front end a screw passes through each slip or strip, the point of which pressing
on an iron plate placed on the pin block, so that when the screw is turned the

page_text: slip is raised or depressed, and the pitch of the string is at once regulated to the
utmost nicety and with the greatest ease. At the back these slips or strips of
metal may either be hinged or simply held down by a bent piece of metal, as
indicated in the accompanying Drawings, Figure 3. It may be explained
that the want of a hollow or belly-shaped sound board has long been felt, but
as without a counterstrain the upright posts or bracings require to be brought
to the front so as to support the pin or rest block, there could be no room
left for a sufficient depth of hollow to make it effectual; the counterbalancing
strain enables the uprights to be cut away as far as the centre, thus giving
ample room for the object desired without the risk of the rest block giving
way.
And in order that my said Invention may be properly understood, I now
proceed more particularly to set forth the system, mode, or manner in or
under which the same is or may be used or practically carried into effect,
reference being bad to the explanatory Sheet of Drawings which I have here-
unto appended, that is to say,-
Figure 1 is a plan, and Figure 2 a section on the line a, a, Figure 1,
showing the mode of constructing that part of the framing of pianofortes
to which the cords or wires are attached, and to which the mode of
counterbalancing (which constitutes the first part of my Invention) is
applied.
A, A, are the ordinary pin blocks supported at the requisite distance apart
from each other by the braces B. As pianofortes are at present constructed,
the whole strain or tension which is put on the cords C is thrown upon one
side of the braces B, which in some instances fail by bending. In order to
counterbalance the strain or pull of the cords or wires C, I apply metal plates
shown at D, attached to the pin blocks A, and which may be made the whole
length of the pin blocks or metal strips merely as shown at E, Figure 1, may
be used; these plates or strips are made to fit round the pin blocks A, as
shown in Figure 2, and to the back ends of these plates or strips rod
couplings F are attached, as shown in Figures 2 and 3. Each of the rods
are screwed at one end, one having a right-hand thread and the other a left-
hand thread, so that the same nut G may pull the coupling rods F together
and counterbalance the strain or pull of the wires or cords C, or the same end
can be attained by one screw, the pulling of the two ends together so as to
form a resistance being the principal object of this part of the Invention, but
the mode described is the one I consider most advantageous. By this means
the pressure is thrown perpendicularly upon the braces B, and they are

page_text: prevented from bending in any direction, and the pin block prevented from
canting.
Another advantage gained by the use of coupling rods to counterbalance
the pull of the cords or wires is that the braces B can be made of less
scantling, and consequently a much deeper belly can be obtained than by
the present mode of constructing pianofortes without the risk of the pin
blocks giving way, as seen on the section, Figures 2 and 3, on which the
braces are shown cut away to give room for this double sound board. H is á
solid partition corresponding to the back of a violin laid against the bracing B,
Figures 2 and 3; I is the belly having suitable openings J, Figure 1, formed
in it to facilitate the reverberation of the sounds; K, Figures 2 and 3, is the
space enclosed between the back partition and the belly, and formed of
suitable depths at the bass and treble sides of the pianoforte.
'
The second part of the Invention is represented in Figure 3, and consists
of tuning slips a resting in the socket 6 (or by any other mode which resists the
tendency to rise). A notch or hook c is formed at the upper end of the slip
to which the cords 'or wires are attached. The requisite amount of tension is
given to the cords c by turning the screw tuning pin d, and elevating or
depressing the tuning slip a. e is a guide by which the slip a is kept in its
proper position.
.
Having now described the nature of my said Invention, and the manner in
or under which the same is or may be used or practically carried into.effect,
I would observe in conclusion, that what I consider novel and original, and
therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First. The mode of counterbalancing the strain or pull of the cords or wires
by means of screwed coupling rods as herein-before. described, or any. mere
modification thereof.
Second. The use of tubular metal braces and iron pin or rest blocks in
combination with the counterbalancing strain, for the purpose of resisting
atmospheric influences on pianofortes, as herein-before described.
Third. The general arrangement of counterbalance, whereby a deep and
double belly can be safely and advantageously employed without the risk of
the pin blocks giving way, and by which the braces can be made smaller and
lighter on account of the strain being balanced and made to rest perpen-
dicularly upon them. by the use of coupling rods, as herein-before described
and shown in the accompanying Sheet of Drawings.
Fourth. The, application and construction of the adjustable tuning slip and

page_text: screw tuning pin, as herein-before described and shown at Figure 3 of the
Drawings, or any mere modification thereof.
In witness whereof, I, the said James Gilmour, have hereunto set my
hand and seal, this Twenty-eighth day of April, One thousand eight
hundred and sixty-eight.
JAMES GILMOUR. (L.S.)