AN IMPROVED CHECK-ACTION AND LEVERAGE SOUNDING BOARD FOR PIANOFORTES
Year: 1881

page_text: LETTERS PATENT to John Brinsmead, of the Firm of John Brinsmead and
Sons, of Wigmore Street, in the County of Middlesex, Pianoforte Manu-
facturers, for an Invention of "AN IMPROVED CHECK-ACTION AND LEVERAGE
SOUNDING BOARD FOR PIANOFORTES."
PROVISIONAL SPECIFICATION left by the said John Brinsmead at the
Office of the Commissioners of Patents on the 16th August 1881.
JOHN BRINSMEAD, of the Firm of John Brinsmead and Sons, of Wigmore
Street, in the County of Middlesex, Pianoforte Manufacturers. "AN IMPROVED
CHECK ACTION AND LEVERAGE SOUNDING BOARD FOR PIANOFORTES."
This Invention relates to certain improvements in the check action and also in
an improved leverage sounding board for pianofortes.
According to the first part of my Invention I centre a simple lever to the back
end of the butt fork with a large hole bored through the opposite end about half
inch deep, in which the leather patch of the escapeinent button works freely, the
same being attached to the sticker by the screw pin guides the sticker both
sideways and upwards until the button comes in contact with the bottom of the
hole in the lever. The lever comes forward by the upward motion of the sticker
and presses it entirely free of its notch, thereby causing the hammer to drop and to
bring it into check.
The spring is at its greatest tension when held by the loop in the butt and
prevents the hammer falling towards the rest until the sticker has returned to its
notch, it being ready then for another blow by a very small motion of the key.
The next part of my Invention relates to an improved system of fixing the
sounding board of pianos by the addition of a leverage arrangement, whereby the
bridges and centre portion of the sounding board can be raised or lowered at
pleasure by a screw appliance passed through the projecting portion of same.
.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Brinsmead in the Great Seal Patent Office on the
16th February 1882.
JOHN BRINSMEAD, of the Firm of John Brinsmead and Sons, of Wigmore
"AN IMPROVED
Street, in the County of Middlesex, Pianoforte. Manufacturers.
CHECK ACTION AND LEVERAGE SOUNDING BOARD FOR PIANOFORTES."
This Invention relates to certain improvements in the check actions and also in
an improved leverage' sounding board for pianofortes.
According to the first part of my Invention I centre a simple lever to the back
end of the butt fork with a large hole bored into the opposite end about half an
inch deep, in which the leather patch of the escapement button works freely; the
escapement button is attached to the sticker by a screw pin, and guides the sticker
both sideways and upward until the button comes in contact with the bottom of
the hole in the lever. The lever comes forward by the upward motion of the
sticker and presses it entirely free of its notch, thereby causing the hammer to
drop and to bring it into check.
The spring is at its greatest tension when held by the loop in the butt, and
prevents the hammer falling towards the rest until the sticker has returned to its
notch, it being ready for another blow by a very small motion of the key.
The next part of my Invention relates to an improved system of fixing the
sounding boards of pianos by the addition of a leverage arrangement, whereby the
bridges and centre portion of the sounding board can be raised or lowered at
pleasure by a screw appliance passed through the projecting portions of same.
My Invention is clearly represented. in the annexed Drawings, in which in
Figure 1 A is the simple lever fastened to the butt fork B at the back end, with a
large hole formed in it at the front lower portion, within which a leather plug or
patch C of the escapement button D is free to play like a loose piston when the
sticker E moves under the action of the key F, the escapement button D being
adjustable by its stem being screw threaded. The plug O is set to act in contact
with the bottom of the hole in the lever A as an abutment, when the sticker E is
lifted and ensures its vertical action without sway or side motion.
The arrangement of the lever A with the escapement button D when the key F
is lifted at its back end causes the top end G of the sticker to get clear of the
notch H, as in Figure 2, to allow the hammer I to fall into check by coming
into contact with and resting on the check pad J. The spring K keeps the
sticker top G in contact with the leather L, the spring being then, at its greatest
tension.
The instant the key is released in a small degree the sticker E drops slightly
and the spring K forces the top G into the notch H to hold the hammer ready for
the next slightest operation on the key. The hammer by this arrangement is
made very sensitive, the smallest motion of the key causing it to strike the wire or
string M.
The next part of my Invention is also clearly represented in the annexed
Drawings at Figure 3, which consists in fixing the sounding board P by a leverage
arrangement caused by bringing the outer edge closer to the cross pieces Q by
screws R, the cross pieces being rigidly attached to the bracing S. The effect of
forcing down the edges of the sounding board is to raise or belly its centre, this
being capable of adjustment by turning the screws R more or less.
The object of this part of my Invention is to render sounding boards of
pianofortes very sensitive, and that they may be adjusted to restore the purity of
sound wave, which is sometimes somewhat harsh from various causes, notably
from unequal closeness of the grain of the wood from which soundboards are
made.

page_text: Having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I claim as my first improvement in
pianoforte check actions hereinbefore recited,―
The piston like plug C working within a hole of the lever A, within which it
acts as an abutment to remove the top end of the sticker. E clear of the notch H
when the sticker is lifted, as and for the purposes set forth and as shown at
Figures 1 and 2 of the annexed Drawings.
Secondly. I claim, raising or bellying the centre portion of the sounding boards
of pianofortes by a depression of the edges adjustable in extent by screw appliances,
for the purposes set forth and substantially as shown at Figure 3 in the annexed
Drawings.
In witness whereof, I, the said John Brinsmead, have hereunto set my hand
and seal, this Fifteenth day of February, in the year of our Lord One
thousand eight hundred and eighty two.
JOHN BRINSMEAD: (L.S.)