THE IMPROVEMENT OF PIANOFORTE ACTIONS
Year: 1871

page_text: LETTERS PATENT to Thomas Jackson, of 21, Orchard Street, Portman
Square, in the County of Middlesex, for the Invention of "THE
IMPROVEMENT OF PIANOFORTE ACTIONS.”
Sealed the 22nd March 1872, and dated the 3rd October 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Jackson
at the Office of the Commissioners of Patents, with his Petition,
on the 3rd October 1871.
I, THOMAS JACKSON, of 21, Orchard Street, Portman Square, in the
5 County of Middlesex, do hereby declare the nature of the said
Invention for "THE IMPROVEMENT OF PIANOFORTE ACTIONS," to be as
follows:-
In order to obtain a perfect escapement and check to the hammer by
means of the hopper, I mount it on a block which is fixed on the key;
the hopper is joined to this block at a point just below the fly; between
the joint and the fly a lever is inserted the outer end of which acts
•

page_text: against an adjustable rail attached to the one on which the levers are
fixed; by this arrangement the action of the hopper is backwards instead
of forward as at present in use; the back of the hopper is of the same
length as the fly, in the middle of its length a screw is inserted which
passes through the fly with a button on each side of it, one to regulate 5
the escapement, the other the distance for the hammer to fall from the
string after giving the blow; at the upper end there is another screw
and button which, acting against the end of the lever to which the
sticker is attached, serves for the check. This lever where it comes in
contact with the hopper is made thicker on the under side, with an 1
incline towards the hinge; the spring causing the hopper to return to its
place is fixed in the block on the key, and acts against the upper end of
the fly. When the finger key is depressed and just at the time when
the escape is required, the lever in the hopper is brought up against the
adjustable rail and made to turn on its centre, causing the escapement 1
and check in tlie manner before described.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Jackson in the Great Seal Patent Office
on the 3rd April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS 2
JACKSON, of 21, Orchard Street, Portman Square, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of October, in the year
of our Lord One thousand cight hundred and seventy-one, in the thirty- 2
fifth year of Her reign, did, for Herself, Her heirs and successors, givo
and grant unto me, the said Thomas Jackson, Her special licenco
that I, the said Thomas Jackson, my executors, administrators, and
assigns, or such others as I, the said Thomas Jackson, my executors,
administrators, and assigns, should at any time agree with, and no 3
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 "THE IMPROVE-
MENT IN PIANOFORTE ACTIONS," upon the condition, (amongst others,) that 3

page_text: I, the said Thomas Jacksori, 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.

page_text: against the fixed rail, is made to turn on its centre or hinge, causing a
perfect escape and check to the hammer by the means before described.
In witness whereof, I, the said Thomas Jackson, have hereunto
set my hand and seal, this Third day of April, in the year of
our Lord One thousand eight hundred and seventy-two.
E