CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF PIANOFORTES
Year: 1827

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PIERRE
ERARD, of Great Marlborough Street, in the County of Middlesex, Musical
Instrument Maker, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,.
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twentieth day of February, One thousand eight hundred and
twenty-seven, in the eighth year of His reign, did, for Himself, His heirs and
successors, give and grant unto me, the said Pierre Erard, His especial
licence, that I, the said Pierre Erard, my exors, adññors, and assigns, or such
others, as I, the said Pierre Erard, my exors, admors, 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, the Invention of "CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF
PIANOFORTES" (being communications from a certain foreigner residing abroad,
and discoveries by myself); in which said Letters Patent is contained a
proviso, obliging me, the said Pierre Erard, by an instrument in writing under
my hand and seal, particularly to describe and ascertain the nature of the said
Invention, and in what manner the same is, to be performed, and to cause the
same to be inrolled in His 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 full and at laran

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Pierre Erard, do hereby declare that the said Invention is described and ascer-
tained in manner following (that is to say) :-
The favorable reception which the corniaisseurs and amateurs have given to
my new grand pianoforte, for which Patents have already been granted to me
in One thousand eight hundred and twenty-one, and One thousand eight hun-
dred and twenty-five, has been an encouragement to me to apply my improve-
ments to pianofortes of other shapes and constructions. The studies and
experiments necessary to effect that object have given rise to the discoveries
and Inventions which are the subject of the present Patent; some points of the
following Inventions or improvements are applicable generally to pianofortes
of all shapes and constructions, but the most important among them is a new
system of action contrived for the grand or square pianoforte, but particularly
well adapted to the square pianoforte, from its being so combined as to take
very little room in its perpendicular height.
I shall first proceed to describe it as follows:-Sheet I? Fig. 1 of the
Drawings hereunto annexed represents a single key of an horizontal pianoforte
at rest or untouched, by which the action will be apparent, cach key having a
repetition of the same parts or movements. Fig. 1I., represents the same
action after the hammer has struck the string, the key being kept
depressed. In both these Figures, and the Figures III., IV., V., VI.,
and VII., the same letters denote the same parts of the action; A, B, C,
is the key; D, E, is the hammer; F, G, is the intermediate lever between the
key and the hammer. This intermediate lever is not mounted on an immoveable
centre, but its centre pin is supported by the key by means of the plates H, H,
made of metal or wood, or any other suitable material; see also Fig. III.,
which is a plan of parts of the action. This intermediate lever F, G, thus
mounted on the key, is kept apart from it by means of a spring I, conveniently
placed between the lever and the key. The lever F, G, is regulated and kept
to its proper height and position by means of the hooked wire, which forms a
fixed stop at K, and which is easily regulated in its height by means of a screw
at the lower end of tho wire, working into the key frame or any other con-
venient rail. The effect of the intermediate lever F, G, mounted upon the
key and its spring I, placed between the key and the lever F, G, is such that
when the key is pressed down, the resistance occasioned by the lever F, meet-
ing the fixed stop at K, causes the end G of the intermediate lever to act with
a greater velocity than could be derived from the key itself at the same distanco
from its centre of motion B. One advantage of this mode of obtaining such
an increased velocity of motion by the intermediate lever F, G, is that it

page_text: facilitates the operation of the mechanism, although it is situated at a con-
venient distance near the centre B of the key.. The next advantage is that the
power of the spring I may be used to keep the damper to the string without
the resistance of an additional spring to the damper. The application of
a damper under the string, as shewn at Figure I., will be sufficient to
illustrate such advantage. The damper shewn in Figure II. is merely intro-
duced to shew that the damper might also be applied upon the key itself,
to act above the string as is generally practised in pianofortes of ordinary
construction; another advantage of the intermediate lever F, G, is that the
counteraction of the spring I on the key must effectually tend to prevent the
key sticking either on the centre pin B or on the front pin A. There are-in.
this action two separate stickers or risers to each hammer, both of which serve
to transmit the motion of the key and intermediate lever to the hammer, and
those two stickers act upon the hammer at different distances from its centre of.
motion. This contrivance being entirely new, and of the greatest advantage,.
I claim the right of applying two such stickers, not only to my present Inven-
tions, but to any and all sorts of actions for pianofortes. In the particular.
system of action represented in the Drawings, the two stickers are mounted
on the intermediate lever F, G; the sticker L is mounted at a convenient
distance from the centre of action II of the intermediate lever F, G; and the.
second sticker M at a further distance from the same centre when the key is at
rest or untouched as in Figure I.; the hammer D, E, rests by its pin in a fork,
which is screwed upon the upper end of the sticker L (see also Figure VII.),
and which can be regulated in its height by means of the screw upon
which this fork is mounted; and when the key is put in motion as in
Figure II., the second sticker M, (from its being mounted on the lever
F, G, at a greater distance from the centre of action H, rises with
greater velocity than the sticker L, and at a convenient time comes in
contact with the hammer at the other point or pin m, and then the
sticker M begins to raise the hammer. Meanwhile the other sticker L con-
tinues to rise at a slower rate, and is brought up to a convenient height to
receive the pin of the hammer in its fall, see Figure II., after the escape-
ment of the upper end of the sticker M from under the pin m, in consequence
of the arm or projecting end O of the sticker M, coming into contact with the
immovable stop P, which is fixed into the key frame or upon the key itself;
the hammer then rests upon the pin l, within the fork so as to be prevented
from dropping down after the escapement has taken place, and the sticker L
continues to support the hammer by-its-pin l, at a small distance from the
strings, until the key has been allowed to rise again sufficiently for the head of

page_text: the sticker M, to regain its original position under the pin m in the hamnier.
The hammer is therefore always supported by the action of one or the other
of the two stickers L or M beneath one or other of the pins 7 or m, so that the
hammer is always ready to answer to the touch with a very small elevation of
the finger end A of the key. In this action at the moment when the escape-
ment of the sticker M takes place, the motion of the check V towards the
hammer, to receive it in its fall, is encreased by the action of such escapement;
this effect is produced as follows:-The socket or centre piece Q, upon which
the sticker M is mounted, has a projecting branch R fixed to it; the lover
part S, O, of the sticker M, is mounted on the same centre but withinside of
the socket Q; one end O of this lover is intercepted by the stop P, to produco
the escapement before mentioned, and the other end S lays on the intermediate
lever F, G, under the branch R with its extremity under the end of a
lever T, which lever is mounted on
moveable about the same centre U.
is such that when the key is acted upon by the finger at the moment that the
contact takes at P, the end S of the lever S, O, is thrown up and carries with
it at the same time the branch R of the sticker M, which being thus thrown
backwards the escapement of the sticker M from under the pin m in the
hammer is performed; at the same time the end of the lever S acts upon the
end of the lover T, and throws the check V forward ready to receive the
hammer in its fall. The advantage of this new and improved mode of making
use of the escapement for the encrease of motion in the check is principally
felt in the return of the key to the level of the other keys, for- as soon
as the key is allowed to rise up again but a very little, the point of
contact at P is destroyed, and the end S, of the lever S, O, quits the branch R,
and drops immediately to the intermediate lever F, G, leaving a spaco between
the branch R, the end S, as shown at Fig. IV. The check V partakes of tho
retrograde motion of the lever S, O, and leaves the hammer perfectly free to
be thrown up again to the string either by the impulse of the sticker L, in the
fork of which its pin 7 rests at that moment, or by the impulse of the sticker M
as soon as it has regained its positions under the pin m, which will take place
when the key is allowed to rise a very little; but until that elevation has
taken place the sticker M bears laterally against the pin m, so as to be
prevented from coming under it, as shewn at Fig. IV. It is obvious that if
the motion of the check V were to depend on the motion of the sticker M,.
only the check would be kept up against the hammer all the while that the
sticker M bears laterally against the pin m, which effect would tend to impede
the quick repetition of blows by the hannmer; on the contrary, with the
a centre of action U, and the check V is
The arrangement of those different pieces

page_text: improved contrivance just described the check V is sure to free the hammer
with a very small rise of the key, and the check being acted upon by the
escapement can never come to the hammer but at the very precise moment
that the 'escapement has taken place. The spring mounted on the pin Z, which
is fixed into the intermediate lever F, G, for the purpose of carrying it,
extends both ways so that one of its ends acts upon the socket Q of the
sticker M, and the other upon the socket U of the check V, to bring them.
back into their proper places as soon as the contact at P ceases. The check V.
may be constructed simply, as shown at Figure V., and as described in my
former Patents herein-before mentioned; but the check shewn in Figures I.,
II., and VI..belongs to the present Invention, and is introduced in the present
action in an improved manner as follows:-The improved check V is shaped
at the head like a hook, and so contrived that the piece y in the stem of the
hammer will be hooked under or locked beneath the hook in the check V
immediately after the blow, so as most effectually to prevent the possibility of
the hammer rebounding to the wires. The pin y is shewn in Fig. VI. at the
moment it is ready to pass the beak of the hook V, in order that it may catch
the pin y; and to allow such effect to take place the check is contrived as
follows:-The socket or centre piece U has a branch a firmly fastened to it
by two pins, òr in any other convenient manner, as shewn by Figure VI. The
lever T moves within the socket U on the same centre pin that carries the
socket; a spring is applied between the lever T and the branch a to press the
lever Tagainst the branch à, so as to make them both move together, when the
end of the lever T is raised up by the end S of the lever S, O, but the spring
yields to the weight of the hammer in its fall from the string, so that the pin y
pushes back the check until the pin y is below the beack of the hook, which
then returns and hooks over the pin y, so as to prevent the hammer rising
again until the key is allowed to rise so much as will remove the end O of the
lever S, O, from its contact with the fixed stop at P, and then the spring mounted
at Z withdraws the check from the pin y, leaving the hammer at liberty to
repeat its blow..
Figure VII. is a front view of the sticker L, and shows its construction;
Z is the pin in the hammer, which is acted upon by the fork, at the upper end
of the sticker L. The lower end is forked to embrace the two sides of the
intermediate lever F, G, and leave room for the 'end S of the lever to act
through it, as seen at Figures I. and II.
Figures VIII., IX.,.and X. exhibit my new ways of hinging the hammers,
which possess very great advantage over the hinges of ordinary construction,
as they admit of the hinge of each hämmer being made much wider, so as to

page_text: give a greater width of bearing and prevent lateral motion of the hammer;
these hinges are made of metal or wood or other suitable material and when
applied to the grand and cabinet pianofortes, or other pianofortes where the line
of the centres of the hammers is parallel to the front of the keys; these wide
hinges are to be constructed as represented in Figures VIII. and IX.; every
alternate hammer has its hinge fixed to the side of the hammer rail, as shown
at b, Figure VIII., and the intermediate hammers are fixed, as usual, on the
top surface of the hammer rail as at d, d, Figures VIII. and IX.; and the
centres of the hinges b, which are fixed to the side of the rail, are as much
below the centres of the intermediate hinges d, d, which are fixed on the top
of that rail as to allow the upper hinges d, d, to project sideways over the
lower hinges b.
Figure X. shows the construction of binges possessing similar advantages,
but which are adapted for square pianofortes or any other kind of pianofortes,
whore the line of the hinges make such an oblique angle with the front of the
keys as will allow the centre of one hinge to be advanced so much before that
of the next adjacent hinge as to admit of wider bearings for the centre pins, as
is shown in the Figure. A side view of the said hinges is shown at ein
Figure X.
Sheet II., Figures I., II., III., and IV. show the improved construction of
the case of the new square pianoforte. The spaces between the pieces of
wood or rails A, A, Figures I. and II., which form the frame or bottom of the
instrument, instead of being closed by pieces of wood over, under, or between
them, are left open in every convenient part of the instrument, especially under
the sounding board, in order to let the tone of the instrument come out from
beneath. To attain this effect and give the instrument the proper strength to
resist the draft of the wires, it requires a new construction of the different
parts of the case, and I apply my improved long arches above the wires with
my improved bolts, which support thoso long arches, as described in my former
Specification to the Patent granted to me on the Fifth day of January, One
thousand eight hundred and twenty-five, for certain improvements on piano-
fortes. a, a, Figure II., shews three of my improved long arches, which are
applied horizontally above the wires; and d, d, Figure III., are my improved
bolts which support those arches; these bolts pass through the whole depth of
the instrument and screw into or are fastened by nuts under the pieces of wood A
which form the bottom or frame at the bottom of the instrument; these bolts
are particularly well adapted to give to the different parts of the instrument the
greatest solidity, for they bind the frame E, E, Figures III. and IV., and
also the block C, C, Figure II., firmly upon the under frame A, A, Figure 1.,

page_text: of the instrument. The holes F, F, through those separate parts correspond
when the different pieces are put one over the other in their proper places, and
the bolts d, d, pass through the holes F and fasten all the pieces together, as
is clearly shewn in section in Figure III. The section Figure III. shews also
the application to the square pianoforte of my improved framing or apparatus,
as described in my former Specification to the Patent granted to me on the
Twenty-second day of December, One thousand eight hundred and twenty-one.
And I have now further improved the same apparatus to be applied to the
grand square cabinet, or any other sort of pianoforte in the manner shewn in
Figure V.; H, H, is the upper part or top piece of such framing applied to the
instrument in the space between the bridge I, and the case K, and I
carry such
fraining all along the instrument, or introduce it at any convenient part of the
instrument in the treble or bass at pleasure; the under bracing L of the instru-
ment is brought up in convenient parts of the instrument as near the sounding
board M, M, as can be to allow it to vibrate freely; the framing IP above the
sounding board is supported and connected with the under bracing La by
upright bolts like N applied in convenient places; these bolts are screwed fast
in the under bracing L, and pass through holes in the sounding board without
touching the same, and have plates o forged or screwed or fixed on them in
any other convenient manner. Those plates o serve for the framing H, H,
between the bridge and the sounding board to rest on, and prevent the framing
being pulled down towards the sounding board by the weight of the wires
which are fastened to the framing H, H. On the top of the framing H, H, a
metal plate P is fitted or let into it, and is fastened by screws, which pass
through the framing H and screw into the under plates o and the bolts N, and
so secure the framing H firmly to the under bracing L beneath the sounding
board, the metal plate P on the top of the framing is made sufficiently wide
to receive the hitch pins to which the strings are fastened at that end, and
such plate may be continued all along the instrument or merely put in separate
pieces in convenient parts of the instrument, treble or bass.
But such metal plate behind the bridge on the sounding board to receive the
hitch pins, having been already practised for many years in various different ways,
I do not claim any right of Invention to metal plate or plates to receive the
hitch pins, but they are merely shewn in the Drawing to explain the way of
using such plate in concert with my improved bolts and framing; and in case
such metal plates are not made use of, small round plates or washers, are
introduced to fit on the bolts and receive the heads of the small screws, which
fasten the framing to the collars o on the bolts; and whether the metal plate P
is introduced or not it is obvious that the framing H, the sides of the case K,

page_text: and the linings Q, Q, Q, must be composed of different pieces of wood, so
arranged that the grain of them in crossing each other may give the sufficient
solidity and firmness to such framing to form almost one folis piecc, which
will not be injured by the weight or draft of the wires on the hitch pins.
Figure VI. shows the construction of the upper end of a bolt to be applied
in the square pianoforte at S, Figure II., to sustain one end of the long arch a.
The upper end of the bolt is so crooked as to allow the last wires of the bass
to pass clear by it under the long arch, but the shank or round part R of the
bolt which passes down into the woodwork below is immediately beneath the
arch.
In. witness whereof, I, the said Pierre Erard, have hereunto set my hand
and scal, this Eighth day of August, in the year of our Lord One
thousand eight hundred and twenty-seven.