IMPROVEMENTS ON THE MECHANISM OF HORIZONTAL, GRAND, AND SQUARE PIANOFORTES
Year: 1835

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
STEWART, of George Street, Euston Square, in the County of Middlesex,
Pianoforte Maker, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fifteenth day of January, in the fifth year of His reign,
did, for Himself, His heirs and successors, give and grant unto me, the
said James Stewart, His especial licence, full power, sole privilege and
authority, that I, the said James Stewart, my exors, adññiors, and assigns,
or such others as I, the said James Stewart, my exors, adiñors, or assigns,
should at any time agree with, and no others, from time to time and at
all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS ON THE MECHANISM
OF HORIZONTAL, GRAND, AND SQUARE PIANOFORTES;" in which said Letters Patent
is contained a proviso that I, the said James Stewart, shall cause a par-
ticular description of the nature of my said Invention, and in what manner
the same is to be performed, to be inrolled in His said Majesty's High
Court of Chancery within six calendar months next and immediately after
the date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
James Stewart, do hereby declare the nature of my said Invention, and the
manner in which the same is to be performed, are fully described and

page_text: DESCRIPTION OF DRAWING NO. 1.
No. 1, the key; 2, center of the key; 3, small wood block fixed on the
key, having a pin passed through it covered with cloth around which a double
spring of wire (Nos. 4 and 5) passes, one end of which spring is fixed in the
key No. 1. and the other end acts on the crank of the hammer lever (No. 6)
so as by pressing the end of the crank upwards to keep the extremity of the
hammer lever (No. 7) in its proper position in the notch of the center block
of the hammer (No. 11). No. 3 center of haminer lever fixed in a small
block of wood) No. 9 which is screwed to the key (No. 1). No. 104, the escape-
ment, which is formed of a piece of wire, one end of which is fixed in the key
and the other end is bent down in a semicircular form, having a screw at its
termination on which is fixed a wooden button guarded with cloth. No. 10"
more clearly describes the construction of this escapement by exhibiting it in
a side view. The wooden button being secured on a screw, may be readily
raised or lowered by turning it with the fingers, and thus regulated to the
proper distance from the end of the crank No. 6 so as to come in contact
with the same when the key is pressed, and to cause the hammer lever No. 7
to escape from the notch of the center block of the hammer (No. 11) just
before the hammer head (No. 12) comes in contact with the strings. No. 13,
hammer center secured on the hammer rail No. 14; No. 15, the check to
arrest the hammer on its descent from the strings.
I claim as the first part of my improvements the mode of applying as
escapement on the key herein described.
DESCRIPTION OF DRAWING No. 2.
This Drawing represents the second part of my improvements, consisting in
a mode of applying the lever commonly called the grasshopper lever without
the use of the under hammer usually employed in square pianofortes. The
novel and essential difference of my mode of application is this: Instead of
letting the lever No. 1 always rest on the regulating button No. 2, as in the
old mode of applying it, I make the lever No. 1 rest on the notch of the center
block of the hammer No. 3, and place the button No. 2 at such a distance
from the lever No. 1 as only to come in contact with the lever No. 1 when
the key is in its downward motion, and thus to cause the hammer lever No. 1
to escape from the notch of the center block of the hammer (No. 3) just

page_text: before the hammer head comes in contact with the springs. A little above
the hinge or centre of the lever No. 1 I apply a small block of wood (No. 4)
projecting about three quarters of an inch, upon which the spring No. 5 acts
so as to keep the extremity of the lever No. 1 in its proper position in the
notch of the centre block of the hammer (No. 3). No. 6 is a small block of
wood fixed on the key with a pin passed through it covered with cloth around
which the spring No. 5 passes. The lower end of the spring is fixed in the
key No. 7.
Having thus described the improvements constituting my Inventions, I
would have it understood that I lay no claim to the parts separately, but
confine my claim, first, to the mode of applying the escapement No. 10 A on
the key No. 1; and, secondly, the mode of applying the hammer lever No. 1
in Drawing No. 2, as above described.
In witness whereof, I, the said James Stewart, have hereunto set my
hand and seal, this Fifteenth day of July, in the year of our Lord
One thousand eight hundred and thirty-five
Inrolled the Fifteenth day of July, in the year of our Lord One thousand
eight hundred and thirty-five.