IMPROVE- MENTS IN OR RELATING TO THE CONSTRUCTION OF PIANOFORTE ACTIONS
Year: 1881

page_text: LETTERS PATENT to Frederick Luther Mitchell, of 27, Violet Street, Halifax,
in the County of York, Pianoforte Maker, for an Invention of "IMPROVE-
MENTS IN OR RELATING TO THE CONSTRUCTION OF PIANOFORTE ACTIONS
PROVISIONAL SPECIFICATION left by the said Frederick Luther Mitchell
at the Office of the Commissioners of Patents on the 8th August 1881.
FREDERICK LUTHER MITCHELL, of 27, Violet Street, Halifax, in the County of
York, Pianoforte Maker. "IMPROVEMENTS IN OR RELATING TO THE CONSTRUCTION
OF PIANOFORTE ACTIONS."
This Invention has reference to improvements in or relating to the construction
of pianoforte actions, the improvements being applicable to all kinds of pianofortes,
and the objects of the Invention are, to avoid all complication in the arrangement
of the action or hammer mechanism; to simplify and greatly reduce the number of
parts, dispensing with the majority of the usual details; to ensure greater strength
of construction, durability of wear, and reliability and effectiveness of action; to
supply a perfect check to prevent the recoil or rebound of the hammer against the
string after a blow upon a totally new principle (and without the wedging of the
hammer by which the checking thereof is at present effected, and which, however
adapted, causes more or less "blocking" of the hammer against the string when
affected by damp, and which is a very undesirable feature in pianofortes), and
which will yet allow of the most rapid and perfect freedom of repetition even after
the hardest blow; to supply an escapement in one with the check, and which will
cause the hammer to be constantly under the direct command of the key, no matter
how rapid the repetition may require to be; to materially lessen the time occupied
in fitting and regulating the action; to supply an action more powerful, simpler,
and more effective, and more perfect in every requirement than any existing
actions at a greatly reduced cost, and one less liable (owing to its avoidance of
complication) to be misused by tuners who have not had a thoroughly practical
experience in action-fitting, or to be injured by rough usage.
The checking of the hammer has hitherto been effected by what is known as
wedging it, and though this has been successfully done it has been always more

page_text: or less at the expense of the perfect repetition, which it hindered, as in all such
actions the key is obliged to be lifted to a considerable degree to allow the hopper
to spring into its position upon the hammer-butt. An action which is at once
strong, durable, a perfect check, and which will allow of rapid and perfect
repetition, has been a desideratum from the commencement of the manufacture of
pianos.
These advantages my improved action attains; it is perfect of its kind, and the
lever acts as check, augmenter, and escapement in one, as hereinafter more
particularly described; it checks the hammer so effectually that the slightest tremor
or oscillation of it is not visible, preventing the slightest rebound without a fresh
blow on the key.
The principal feature of my Invention consists in the application and use of a
lever-check (in lieu of the above referred to usual wedge-check, with various
modifications of which all check actions have hitherto been constructed), which
receives its impetus direct from the rear end of the key, and transmits the motion
(without the intervention of any complication of intermediary details) direct to
the hammer by means of a striker connecting the two. I am thus enabled to
exert a powerful leverage upon the hammer without any waste of energy due to
friction between a number of parts, and thus add considerably to the power of the
blow and to attain a perfect command of the hammer. Upon the hammer striking
the string the improved lever-check is repulsed and exerts an immediate and
direct opposite or detaining influence upon the hammer checking it while the key
is kept depressed but a very slight distance from the string, and so that it cannot
recoil or rebound against the string without a fresh blow on the key, but so that
the slightest release and depression of the key will be sufficient for a comparatively
vigorous repetition, which may be continued as rapidly as it is possible to play
upon the key.
I attain this perfection of action by centreing or connecting the lower end of the
sticker with the lever-check at a point in rear, and preferably within one half
inch of the centre upon which the lever-check works, and the upper end of the
sticker I connect direct to the hammer-butt, and this allows of the check having
such an immediate and direct control over the hammer as will altogether prevent
the possibility of a recoil thereof to the string without repeating the blow on the
key, and yet checking it so near its work that the most rapid repetition of the
blow can be performed with the slightest movement of the key without causing it
to have to assume or travel to or nearly to its original position as in existing
actions, and the hammer being so directly connected with the key and so perfectly
under its command cannot as in existing actions jump away from the sticker and
keep the latter waiting for its return. The fore end of the check-lever works
freely upon its centre, which is carried by a regulating-block, which is connected
with the key by means of a regulating screw, which allows of the block being
raised or lowered as may be required for attaining uniformity in fitting the
action; the rear end of the check-lever is or may be weighted, unless made of
heavy wood, and simply rests on the key, and when the key is struck it and the
hammer receive their motion simultaneously, the hammer through the check and
sticker, and after the action of the key has ceased the check lever for the moment
escapes from the key and acts independently as an augmenter, and proceeds with
the hammer till the latter strikes the string; but the time occupied in this
independent action and the return to the key, and in the simultaneous going to
and striking the string by the hammer and its return to the control of the check
is so short as not to be perceptible, and hence the most perfect repetition may be
attained however rapid it may require to be, and after the hardest blow the
mere easing of the key from the front washer will give a comparatively vigorous
repetition.
.
The check-lever acting with such freedom and directness enables the hammer
to be rigidly checked within about one quarter of an inch or less of the string
(the distance being determined by the depth of touch) and thus ready for a

page_text: repetition of the blow with any practicable rapidity by the slightest. release and
depression of the key.
"
The above described direct connection of the hammer, sticker, and lever-check
by means of the regulating-block with the key avoids the complicated
arrangements of the various separate parts, such as the hoppers, prolongs, and
other parts which form part of all existing actions, and the great loss of power
consequent upon the friction thereof. And as additional advantages it also
prevents the disagreeable effect known as blocking" in ordinary actions, and
which is due to the swelling of the wash-leather (by the contraction of damp or
atmospheric humidity to which all pianos are of necessity more or less exposed),
which is freely used between the parts of all existing actions, and which coming
in contact with the top of the hopper causes the "blocking," and as I quite
dispense with the use of wash-leather this by itself is a great improvement. It
moreover prevents much (wear between the parts which in all existing actions
makes oft-recurring regulation an absolute necessity, and it dispenses with the
long and tedious process of regulation to which all pianos are at present subjected
before leaving the manufactory.
I construct the action in such a manner as that a complete section of it for each.
key may be removed without disconnection of its parts by simply unscrewing two
screws, the one of which secures a small plate which secures the centre-pin of the
check-lever to the regulating block, and the other of which secures an upright by
which the hammer and damper are carried to the hammer rail. The key may be
removed by easing the first screw. This improved construction also allows of the
regulation being readily and perfectly effected without removal of the action from
the pianoforte, the keys regulating the checking distance by means of the said
block which can be raised or lowered as required by means of the said screw, and
a regulating screw passing through the sticker regulating the damper.
As hereinbefore referred to, I centre the hammer and the damper upon the same
upright or foundation, which greatly simplifies the construction of the action,
rendering it more compact, and allows the damper to be adapted and fitted in
such a manner as that it may be effectively controlled by a soft-faced button at
the end of the regulating screw, which screws through the sticker and passes freely
through the said upright, this button working against an incline carried by the
front of the damper below its centre, and causing the damper-head to be removed
from the string as the hammer approaches to strike it, and the damper-head is
brought back to the string upon the receding of the haminer by means of a spring.
which is fixed to the rear side of the damper below its centre, and has its free
depending end held by a silk loop which passes freely through the damper, and
is made fast to the said upright or foundation; by this improved arrangement the
spring is enabled to exert a powerful influence upon the damper-head without
causing any friction upon the back of the damper. By turning the said regulating
screw the distance between the damper and the string may be regulated to a nicety,
so as to allow of free vibration to the string when struck by the hammer.
-
The improved lever-check may be adapted to existing actions so far as it or
modifications thereof are applicable, and I in no way limit myself to any exact con-
struction or conformation thereof, nor to any particular mode of applying it, as this
will greatly depend upon the arrangement of the action of the instrument to which
it is to be fitted. The principle of the present Invention relating more particularly.
to the application to and use in connection with pianoforte-actions of a lever-check
actuated directly from the key, and having an immediate and direct action upon'
and control of the haminer (in lieu of checks constructed as hitherto in all actions
upon some modification of the wedge principle) than to any particular construction
of the check or to any particular method of applying it, which will necessarily.
vary in different instruments, though in applying it to any action it greatly.
simplifies the latter, both as regards the number of parts and the arrangement
thereof, and it enables the key to have such an immediate and perfect control of
the hammer as is altogether unattainable in the most perfect of existing actions;

page_text: besides attaining the hereinbefore mentioned very superior advantages of increase
of power and of attaining the utmost delicacy of action, which cannot fail to
recommend itself to the most fastidious pianists, as the touch can be so humoured
as to suit any variety of taste.
I will however as an example now describe another modification or arrangement
of working the hammer and damper in connection with the improved lever-check.
In this modification the hammer-butt in lieu of being centred to the said
upright, as described in the previous modification, is centred to a projection rising
from a longitudinal rail running along the piano, but it is connected by the sticker
direct to the lever-check, as hereinbefore described. The damper-regulating-screw is
carried by the hammer-butt in lieu of by the sticker, as in the previous modification,
and works through the said upright or fork against cloth on the front side of the
damper below its centre, and thus strikes the damper-head away from the string.
The damper is supported and brought back to position, as previously described.
The sticker in this and in the preceding modification can be lengthened or shortened
at will to suit the size of the pianos to which the improved action is to be adapted;
the lengthening of the stickers and of the action supports is all that is necessary
to effect the lengthening of the action.
In fitting the action its frame and the key frame may be fixed together so that
they can be together taken out or put in, or the frame may be otherwise arranged
in such a manner as will best suit the particular instrument to which the action
is to be adapted.
:
I find it of advantage that all the washers under the keys should be firmly
bedded, and that the keys be permanently levelled before putting in the action.
The action (which, as hereinbefore referred to, may be complete in sections with
the exception of the hammers and damper-heads), I then screw to the hammer-
rail section by section, and connect each section with its regulating-block, as
hereinbefore mentioned, the block having been previously screwed to its key,
and great care having been taken to have them all level before connecting the
action thereto. I then fix the hammers and the damper-heads, taking care that
they are level not only on the top but on the outside of the hammer-heads. When
this system is carried out carefully no further regulating should be required, and
the action without wilful abuse cannot get out of order.
It will of course be understood that I do not confine myself to any exact form
or arrangement of the parts, as hereinbefore referred to, but what I consider to be
material parts of my improvements and to be characteristic of my Invention are,
the use of the check-lever in any. variety of action however combined therewith
or applied thereto, and its application as an augmenter and escapement, and the.
absolute connection between the hammer, the sticker, the lever-check, the regulating-
block, and the key when in the act of working.. I do not lay any particular stress
upon my herein before described improved mode of working the damper in
connection with upright actions apart from its use in combination with the check-
lever, although I believe it to be of greater simplicity and more perfect in action
than the usual arrangements.
The ordinary balance of the key will answer the purpose of this action, which
being so remarkably free and prompt allows more scope for varieties of taste with
regard to, touch than any existing action, and will give ample satisfaction to the
most fastidious pianist.
The usual stop-rail behind the action must always be used to preserve the
uniformity of the touch.
The ordinary piano and forte pedals are used, and if the usual diminuendo pedal
is used it will be found to work upon the keys carrying them up with the
hammers, thereby obviating that disagreeable space caused in the ordinary
application of it by the lifting of the action off the keys (in low pianos) or the
prolongs by reason of each hammer taking up its corresponding key, thereby
making the touch gradually or suddenly more shallow, giving piano effects much
more agreeably than usual,

page_text: The parts of the action being fitted together by centre pins which are bushed in
cloth, as is usual, the friction between the parts is reduced to a minimum, and the
usual rattling and squeaking of the hoppers and prolongs is of course obviated.
The action may be fitted into the tallest pianos without additional expense, and
when adapted to horizontal pianos the ordinary damper peculiar to them being
applied as usual, the action will not be resisted in the slightest degree, allowing
the hammer, check, and augmenter to proceed with a force that will bring out
more power than any existing action.
I prefer to use cloth of good firm quality for the washers under the keys and for
the under part of the usual back-rail for the purpose of keeping the touch more
uniform, as the good condition in which the piano action may be kept for a long
period depends much upon it, and when the instrument needs regulating after
years of hard use, the re-levelling of the keys and re-adjustment of the touch will
be found all that is necessary to restore its condition.
As regards the cost and fitting, not only is the cost upon the best check-actions
reduced by quite one half, but the fitting of the improved action into the
instrument may be done in one half the time usually required.

page_text: No text detected.

page_text: To attain the perfection of action to which reference is hereinbefore and herein-
after made I centre or connect the lower end of the sticker with and between the
bifurcated sides of the check-lever at a point 6 in rear, and preferably within about
one half an inch of the centre 7, upon which the check-lever works, and the
upper end of the sticker is bifurcated and connected directly at 8 to the
hammer-butt, embracing a narrowed part or entering between a bifurcated part
thereof. The fore or bifurcated end of the check-lever works freely upon its
centre 7, which is carried by an adjustable and reversible regulating-block 9, which
also enters at its upper narrowed part between the bifurcations of the check-lever,
and is connected with the key by means of a regulating-screw 10, which allows of
the block being raised or lowered, as may be required for attaining uniformity in
fitting the action; the rear end of the check-lever is (or may be) weighted as at 11,
unless made of heavy wood, and it is cushioned or padded with cloth at 12, where
it simply rests on the key.
By this direct connection I am enabled to exert a more than usually powerful
leverage upon the hammer, and avoid waste of energy due to friction between a
number of parts and thus add considerably to the force of the blow, and the check-
lever acting with such freedom and directness enables the hammer to be rigidly
checked within about one quarter of an inch or less of the string (the distance
being determined by the depth of "touch" at the finger end of the key, and thus
ready for a repetition of the blow with any practicable rapidity by the slightest
release and depression of the key.
'
When in a position of rest the parts of the improved actions assume the
positions relatively shown in Figs. 1, 3, & 5, but when the key is depressed or
struck the check-lever and hammer receive their motion simultaneously there with,.
and direct therefrom the hammer through the check-lever and sticker, and as or at
the instant the action of the key ceases the parts assume or have the positions
relatively shown in full lines in Figs. 2, 4, & 6, but owing to the impulse it received
from the stroke of the key, the free end of the check-lever then for the moment
escapes therefrom and acts independently as an augmenter, and proceeds with the
sticker and hammer till the latter strikes the string, when or at which moment
these parts assume or bave the positions relatively shown in dotted lines in
Figs. 2, 4, & 6, and which is the checking position, in which position they all
remain while or so long as the key is kept depressed, the hammer being thus
perfectly checked but a very slight distance from the string, allowing of free
vibration thereof, and in such a manner as will altogether prevent the possibility.
of a recoil or rebound thereof against the string without a fresh blow on the key;
and yet (the time occupied in the above mentioned independent action of the
check-lever and its return to the key, and in the simultaneous going to and striking
the string by the hammer, and its return to the checking position under the control
of the lever 1, being so short as not to be perceptible) the most perfect repetition
may be obtained however rapid it may require to be (and quite irrespective of the
force of the preceding blow) the merest easing or slightest release from the usual
front washer at the finger end of the key, and depression of the key being sufficient
for a comparatively vigorous repetition, which may be continued as rapidly as
it is possible to play upon the key, this perfection of action being thus effected.
without causing the key and other parts of the action to have to assume or travel
to or nearly to its or their original position, as is required in existing actions, the
hammer being under such an immediate and direct control of the check-lever,
and so perfectly under the command of the key, cannot as in existing actions
jump away from the sticker and keep the latter waiting for its return, hindering
the perfect repetition.
The above described direct connection of the hammer, sticker; and lever-check
by means of the regulating block with the key avoids the complicated arrangements
of the various separate parts, such as the hoppers, prolongs, and other parts which
form part of all existing actions, and the great loss of power consequent upon the
friction thereof. And as additional advantages it also prevents the disagreeable

page_text: effect known as "blocking" in ordinary actions, and which is due to the swelling
of the wash-leather (by the contraction of damp or atmospheric humidity to
which all pianos are of necessity more or less exposed) which is freely used between
the parts of all existing actions, and which coming in contact with the top of the
hopper causes the "blocking," and as I quite dispense with the use of wash-leather,
this by itself is a great improvement. It moreover prevents much wear between
the parts, which in all existing actions makes oft-recurring regulation an absolute
necessity, and it dispenses with the long and tedious process of regulation to which
all pianos are at present subjected before leaving the manufactory.
I construct the action in such a manner as that a complete section of it for each
key may be removed without disconnection of its parts by simply unscrewing two
screws 14, 15, (reference now being had to Figs 1 & 2) the former of which secures
a small plate 16 which secures the centre pin 7 of the check-lever to the regulating-
block, and the latter of which secures an upright 17 by which the hammer and
damper are carried to the rail 18. This improved construction also allows of the
regulation being readily and perfectly effected without removal of the action from
the pianoforte, the keys regulating the checking distance by means of the block 9,
which can be raised or lowered as required by means of the screw 10, and is
provided with two centres for the pin 7 for nicety of adjustment, and a regulating
screw 19 which is screwed through the sticker, regulating the damper 20.
As hereinbefore referred to, I centre the hammer at 32 (similarly to the way in
which I centre the check-lever) and the damper at 23, upon the same upright or
foundation 17, which greatly simplifies the construction of the action, rendering it
more compact, and allows the damper to be adapted and fitted in such a manner
as that it may be effectively controlled by a soft-faced button 21 at the end of the
regulating screw 19 which passes freely through the upright, the button working
against an incline 22 carried by the front of the damper below its centre of motion 23,
and causing the damper head 24 to be removed from the string 33 as the hammer
approaches to strike it, as shown in Figs. 2, 4, & 6, and the damper-head is brought
back to the string upon the receding of the hammer, as shown in Figs. 1, 3, and 5,
by means of a spring 25 which is fixed to the rear side of the damper below its
centre 23, and has its free depending end held by a silk loop 26 which passes freely
through the damper and is made fast to the upright 17; by this improved
arrangement the spring 25 is enabled to exert a powerful influence upon the
damper-head without causing any friction upon the back of the damper. By
turning the regulating-screw 19, the distance between the damper-head and the
string may be regulated to a nicety, so as to allow of the free vibration of the string
when struck by the hammer.
The improved lever-check may be adapted to existing actions, so far as it or
modifications thereof are applicable; and I in no way limit myself to any exact
construction or conformation thereof, nor to any particular mode of applying it, as
this will greatly depend upon the arrangement of the action of the instrument to
which it is to be fitted; the principle of the present Invention relating more
particularly to the application to and use in connection with pianoforte actions of a
lever-check actuated directly from the key, and having an immediate and direct
action upon and control of the hammer (in lieu of checks constructed as hitherto in
all actions upon some modification of the wedge principle) than to any particular
construction of the check or to any particular method of applying it, which will
necessarily vary in different instruments; though in applying it to any action it
greatly simplifies the latter both as regards the number of parts and the arrange-
ment thereof, and it enables the key to have such an immediate and perfect control
of the hammer as is altogether unattainable in the most perfect of existing actions,
besides attaining the hereinbefore mentioned very superior advantages of increase
of power and of attaining the utmost delicacy of action, which cannot fail to satisfy
the most fastidious pianists, as the touch can be so humoured as to suit any variety
of taste.
I will however as an example now describe another modification or arrangement

page_text: of working the hammer and damper in connection with the improved lever-check,
reference now being had to Figs. 3 and 4.
In this modification the hammer butt, in lieu of being centred to the upright 17,
as described in the previous modification, and illustrated in Figs. 1 and 2, is centred
to a separate projection 17* rising from the rail 18, but it is connected by the
sticker direct to the check-lever, as hereinbefore described. The damper regulating-
screw 19 is screwed through the hammer butt in lieu of through the sticker, as in
the previous modification, and works through the upright 17 against cloth 22 on the
front side of the damper below its centre, and thus strikes the damper-head away
from the string. The damper is supported and brought back to position as
previously described. The sticker in this and in the preceding modification' can
be lengthened or shortened at will to suit the size of pianos to which the
improved action is to be adapted, the lengthening of the sticker and of the
action supports 17 is all that is necessary to effect the lengthening of the action.
In fitting the action its frame and the key frame may be fixed together so that
they can be together taken out or put in, or the frame may be otherwise
arranged in such a a manner as will best suit the particular instrument to which
the action is to be adapted.
I find it of advantage that all the washers 28, 29, and at the finger end
under the keys, should be firmly bedded, and that the keys be permanently levelled
before putting in the action. I screw the action to the rail, section by section,
and connect each section with its regulating block, as herein before mentioned, the
blocks having been previously screwed to their respective keys, and great care
having been taken to have them all level before connecting the sections of the
action thereto. I then fix the hammers and the damper-heads, taking care that
they are level, not only at the top but on the outside of the hammer-heads. When
this system is carried out carefully no further regulating should be required, and
the whole arrangement without wilful abuse cannot get out of order.
The ordinary balance of the key will answer the purpose of the action, which
being so remarkably free and prompt allows more scope for varieties of taste with
regard to touch than any existing action, and will give perfect satisfaction to the
most fastidious pianists.
The usual rest rail 30 must always be used, and this will support the hammer
and its attachments when the check-lever is disconnected from the regulating-
block, and this disconnection will enable the key to be taken out.
The ordinary piano and forte pedals are used, and if the usual diminuendo pedal
is used it will be found to work upon the keys, carrying them up with the hammers,
thereby obviating that disagreeable space caused in the ordinary application of it
by the lifting of the action off the keys (in low pianos) or the prolongs by reason
of each hammer taking up its corresponding key, thereby making the touch
gradually or suddenly more shallow, giving piano effects much more agreeable than
usually.
The parts of the action being fitted together by centre-pins which are bushed in
cloth as is usual, the friction between them is reduced to a minimum, and the usual
rattling and squeaking of the hoppers and prolongs is of course obviated.
The action may be fitted into the tallest pianos without additional expense, and
when adapted to horizontal pianos, one example of which application is illustrated
in Figs. 5 and 6, the ordinary damper peculiar to them being applied as usual, the
action will not be resisted in the slightest degree, allowing the check augmenter
and hammer to proceed with a force that will bring out more power than any
existing action.
I prefer to use cloth of good firm quality for all the washers under the keys,
and for the under part of the usual back rail at 31 for the purpose of keeping the
touch more uniform, as the good condition in which the piano-action may be kept
for a long period depends much upon this, and when the instrument needs regu-
lating after years of hard use the re-levelling of the keys and re-adjustment of the
touch will be found all that is necessary to restore its condition.

page_text: As regards the cost and fitting, not only is the cost upon the best check actions
reduced by quite one half, but the fitting of the improved action into the instrument
may be done in one half the time usually required.
Having now particularly described and ascertained the nature & objects of my
said Invention, together with the manner in which the same is to be or may be
performed or carried into practical effect, I would remark in conclusion that I
desire it should be understood that what I consider to be novel and original, and
to be material parts of iny improvements, and to be characteristic of my Invention,
and which I therefore claim (without confining myself to any exact form or
arrangement of the parts) as constituting the Invention secured to me under the
herein before in part recited Letters Patent are,-
The combination with the action or hammer mechanism of pianofortes, of an
adjustable check-lever or lever-check which receives its impetus direct from the
rear end of the key, and transmits the motion direct to the hammer-butt by means
of a sticker connecting the two, substantially as hereinbefore described and as
illustrated on the accompanying Drawings.
The application and use of an adjustable check-lever acting also as an augmenter
and escapement, and which is actuated as and controls the hammer as, or has the
action substantially as hereinbefore described, to and in any variety of pianoforte
action, however combined therewith or applied thereto...
And especially I claim the particular combinations and arrangements of the
component parts of pianoforte actions substantially as hereinbefore described with
reference respectively to Figs. 1, 3, and 5 of the accompanying Drawings, and in
which the connection between the hammer, the sticker, the lever-check, the
regulating block, and the key when in the act of work is absolute and direct, and
enables the key and lever-check to have that direct command and control over the
hammer, and to attain that perfection of action which is hereinbefore described.
I would here remark that I do not lay any particular stress upon my herein before
described improved modes of working the damper in connection with upright
actions apart from the use thereof in combination with the check-lever and its
connections, as or substantially as hereinbefore described, and as illustrated on the
accompanying Drawings, although I believe it to be of greater simplicity and more
perfect in action than the usual arrangements.
In witness whereof, I, the said Frederick Luther Mitchell, have hereunto
set my hand and seal, this 3rd day of November, in the year of our
Lord One thousand eight hundred and eighty one.