Improvements in Piano Actions.
Year: 1890

page_text: Date of Application, 22nd July, 1890-Accepted. 23rd Aug., 1890
COMPLETE SPECIFICATION.
Improvements in Piano Actions.
I, AUGUSTUS DEFOE DIMICK, of the Town of Wakefild, County of Middlesex, State
of Massachusetts, United States of America, Piano Maker, do declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The invention relates to pianos in general, and has particular reference to the
mechanism whereby the hammers are caused to deliver the blow upon the strings,
technically known as the "action." It relates especially to vertically arranged action's
designed for use in upright pianos, and has for its objects to cheapen the cost of manu-
facture, to simplify the construction, to reduce the number of parts, to avoid the use
as far as possible of objectionable pivots, and to secure a more direct and positive action
of the several pieces composing the "action," whereby friction is reduced to a minimum,
and a noiseless, easy and sensitive operation of the parts is obtained, and firmness and
precision of action is secured, together with the requisite capability for quick repetition
of the stroke of the hammer.
To this end the invention consists in the construction and arrangement of parts
hereinafter described and claimed, embodying as distinguishing characteristics; a
jack, which, instead of being pivoted upon a bed or jack-lever, interposed between it
and the key, is arranged to slide bodily up and down in or upon suitab e guides in the
action rail and has an adjustable knob on its lower end, the jack being operated by a
direct connection with the key; a damper, which, instead of being pivoted midway of
its length and operated by a lifter on the jack-bed or lever acting between the damper
lever and the action rail, is pivotally mounted at its lower end and operated by a lifter
on the key acting on the opposite side of the damper lever from the rail; an adjustable
stop for the lifter rod, whereby the amount of liberty or clearance between it and the
damper lever may be regulated, in connection with a lifter rod acting on the outer side
of the lever a back-check for the hammer, which, instead of being mounted on the
jack-bed or lever and acting upon a buffer or bunter projecting from the hammer-butt
near its pivot, is arranged to slide in bearings in the action rails and acts upon an
extension of the hammer head, being actuated by the upward movement of the jack
itself; also in minor features and details of construction which will be more
particularly hereinafter pointed out in the claims.
:
In the accompanying drawings forming part of this specification ;
Figures 1 and 2 are side views of the action (the rails only being in section) the
parts being in different positions ;
Figures 3 and 5 are detail views of modifications of certain of the connections; and
Figure 4 a detail of an improved key pad.
Like letters designate corresponding parts in the several figures.
A is the key, pivoted as usual about midway of its length, and provided under its
end with pads a, which may be the ordinary pieces of cloth or felt, as shown in
Figures 1 and 2, or if preferred of the kind shown in Figure 4 to be hereinafter
described. B is the main rail of the action, C the hammer rail, D the damper check
rail to which the usual hammer and damper springs are attached. E the lower rail
to which the damper lever is pivoted, and which has an integral or attached flange e
to guide and help sustain the jack, and H a light rail forming a guide for the
lower end of the hammer check rod and carrying the jack springs. F is the
hammer head, provided with the extension f, for a purpose to be hereinafter described,
the hammer being pivoted at its butt by means of the metal clip to a flange
on the top edge of the main action rail, said clip passing around the pivot pin in the
flange, this clip being in this invention given the particular construction shown for
a purpose presently to be described,

page_text: G is the jack, which, as above stated, instead of being L-shaped is made of a
straight, continuous piece, preferably widened out at some point intermediate of its
ends as shown at g³ and slotted at that place so as to take over and be supported
mainly by a ping projecting from the action rail so as to be capable of a sliding
movement up and down under the action of the key. The lower end of the jack,
instead of being pivoted to the usual jack-bed or lever, is passed through a slot in the
lower rail E and stepped directly upon the key itself, thereby dispensing entirely with
the jack-bed or other intermediate mechanism between the jack and the key and
obtaining a more direct and positive thrust upon the hammer, with a quicker response
to the touch on the key.
The upper part of the jack extends up between the action rail B and the light rail
which is carried by studs g' projecting from the main rail and forms the lower guide
bearing for the sliding hammer check rod. The nose or upper end of the jack is held
normally forward so as to engage the padded shoulder on the hammer-butt by the
expansion spring h fixed to the rail H, though it may be similarly operated by a
small contraction spring fastened at one end to the opposite side of the jack and
secured at the other to the action rail.
In order to trip the jack to permit the return of the hammer after the delivery of
the blow, I use a let off composed of an adjustable stop i, whose stem is screwed
into the jack near its upper end, in connection with a tang or lug on the hammer-
butt: conveniently make use of the clip f' by which the butt is pivoted on the
pin of its flange to form this tang or lug. The clip is, therefore, longer than usual
and is shaped as shown, so that, as the hammer moves forward, it will, at the proper
time, engage the stop i in the jack and trip the latter. By making the stop adjustable
the point in the movement of the hammer where the tripping takes place may be
regulated with exactness.
To prevent the jack when tripped from getting farther away from under the shoulder
of the hammer-butt than is necessary, thereby causing excess of liberty or movement
of the jack and requiring extra work for its returning spring, as well as to
accurately control this liberty of the jack, I provide the pin g with an adjustable
padded head or button h. Upon the threaded rod g2 in the lower end of the jack,
where it passes through the slot in the rail E, I place another adjustable button *
which limits the downward movement of the jack and prevents the action falling
when the key is removed.
The connection between the key and the lower end of the jack may be made in
different ways, of which 1 have shown two in the drawings. In Figures 1 and 2 there
is let into the key a piece of hard wood a¹ having in its upper surface a hemispherical
recess into which fits a rounded knob of rubber or other suitable material on the lower
end of a button I, which, moreover, is made adjustable by screwing on the rod g² to
effect alterations in the length of the jack. It is obvious however, that the parts
might be reversed, that is, the knob be arranged on the piece a', and the
hemispherical recess in the end of the button I. Figure 5 shows a modification of the
above described arrangement. In this form the screw rod and its button and
adjustable stop are dispensed with, and the lower part of the jack is provided with a
key-hole slot taking over a headed pin which takes the place of the flange on the
rail E. The end of the jack is forked and straddles a pivot pin in a rocker mounted.
on the key. Other modifications will suggest themselves to the skilled operator.
As before stated, the damper lever J, instead of being pivoted midway of its length
and operated by a lifter mounted on the jack-bed and acting between the lever and
the rail, is pivotally mounted at its lower end upon the rail E, preferably by a flange
secured thereto and actuated by a lifter L mounted on the key and bearing on the
outside of the lever at about the middle of its length, resulting in a direct lifting of
the damper by the key, giving a quicker, easier and surer action. This lifter is
shown in Figs. 1 and 2 as a pad on the upper end of a vertical rod fixed in the key.
The pad may however, be fixed on the upper end of a rocker as shown in Fig. 3 and
be adjustable in that way, instead of by bending the rody as in the other construction;
or it might even have an adjustable button, like that used in the jack at i. The lever

page_text: is guided near its upper end by a headed pin from the action rail passing through a
key-hole slot in tho lever. By unscrewing the flange at the foot of the lever and
dropping it slightly it may be taken off of the pin.
Instead of mounting the lifter rod K between the damper lever and the rail, which
arrangement requires a considerable cutting away of the latter and gives much
trouble and annoyance in getting at the parts to adjust the liberty or clearance of the
rod, I arrange it on the outer side of the lever and connect it with the action
rail by pivoted links I, as shown, whereby ready access is had to the rod, and the
rail not being cut away is strengthened. To limit the outward movement of the
rod, and to adjust it for the purpose of giving it the proper clearance, I provide
an adjustable catch or hook-shaped stop S, which is screwed into the action rail
and may be adjusted by turning in or out so as to set the bar at a suitable distance
from the damper lever to permit the proper action of the damper on the strings.
The back-check for the hammer has heretofore generally been mounted on the
jack-bed or lever, and arranged to act on a buffer projecting from the hammer
butt. In this invention, it is however, arranged in sliding hearings in the action
rails, and consists of a rod O, whose padded upper end extends above the hammer
rail and plays in the path of the projection on the hammer head, and whose
lower end, extends down below the rail H where it is provided with a padded foot
which rests on a shoulder on the jack formed by the widened, slotted party³.
Upon the threaded upper part of the check rod is an adjustable stop button
limit its downward movement and the check buffer at the top is preferably adjustable
also. The under side of the hammer extension may be faced with leather or felt if
desired to afford a better hold for the check, but it is hardly deemed essential. The
shape and structure of the extension may be varied within wide limits, as I do not
wish to be confined to the shape shown. Any other form or configuration may be
resorted to which experience may demonstrate to be more efficient or desirable.
to
Figs. 1 and 2 show the form of key pad in common use, being a piece of thick
felt. This is somewhat objectionable on account of being affected unfavorably by
atmospheric changes, thereby interfering with the free and easy action of the key.
In Fig. 4 I show a form of pad or rest which is not affected by moisture or
temperature. It consists of a rubber cord or rod c set into a groove in the
piece d and covered by a strip of light felt or any suitable cloth b. While E
have shown it in connection with the key, it could be used if desired on the
hammer check rail, or other point where a check-pad of this character is desired.
The construction of my improved action being as above described the operation
is generally as follows: The depression of the key raises the jack, the damper lift
and the hammer check, freeing the damper from contact with the strings, throwing
the hammer forward to deliver the blow and carrying the hammer check into a
position where it will be engaged by the hammer-head projection after the blow
has been given in order to prevent the rebound of the hammer. As the hammer
moves forward, the tang or lug f' moves in the opposite direction, and striking
The jack
the stop on the jack trips the latter, allowing the hammer to return.
spring acts to restore the jack to its normal position promptly, whereby quick
repetitions of the blow may be given with less than the full stroke of the hammer.
It is apparent that many of the details of the construction and arrangement of
the several parts of my action may be considerably varied; also that some of the
features may be used without employing the whole.
It is to be understood that the rockers shown in the modifications in Figs 3.
and 5 are fixtures on and so far as this invention goes, are parts of the key.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is :-
1. In a piano action, the combination of the main action rail, the lower rail, the
jack sliding in suitable guides or ways on the rails, and the key, the jack resting

page_text: directly upon the key, and having an adjustable knob on its lower end, substantially
as described.
2. The combination of the key, the pivoted hammer, the sliding jack, the jack-
trip consisting of the adjustable stop in the jack and the tang on the hammer-butt,
and the jack-spring, the jack arranged to slide endwise on suitable guides in the
action rail, the spring arranged to restore the jack to place after it has been tripped,
and means to limit the lateral movement of the jack, substantially as described.
3. The combination of the main action rail, the lower rail, the pin from the
former, and the slot in the latter, the sliding jack having a vertical slot in its body
taking over the pin and the lower end of the jack playing in the slot in the lower rail,
and adjustable buttons on the lower end of the jack and the pin in the main rail ;
substantially as described.
4. The combination of the main and lower rails, the pin from the former and the
slot in the latter, the sliding jack having a slot taking over the pin and having its
lower end playing in the slot in the lower rail, the pivoted hammer, and the sliding
hammer-check rod, the lower part of the jack being provided with an adjustable
stop bearing upon the lower rail to prevent the action falling too low; substantially
as described.
5. The combination of the main rail, the hammer flange secured thereto and the
hammer-butt, the latter connected to the pivot pin in the flange by the plate ƒ³
passing around the pin and having its end elongated and bent backward as shown to
act as the jack-trip; substantially as described.
6. The combination of the key, and the jack, the key having a piece of hard wood a
let into its upper surface and having a hemispherical recess, and a rounded knob on
the end of the jack seated in the recess; substantially as described.
7. The combination of the key, the damper lever pivoted, at its lower end to one of
the action rails, and the damper lift, mounted on the key and acting upon the outer or
back side of the lever; substantially as described.
8. The combination of the pivoted damper lever, and the lifter rod, link-connected
to the action rail and lying outside or back of the damper lever; substantially as
described.
9. The combination of the pivoted damper lever, the lifter rod link-connected to the
action rail and lying outside of the damper lever, and an adjustable catch to set the
rod in proper position for the action of the damper; substantially as described.
10. The combination of the hammer head, its extension, the sliding jack, the sliding
hammer check, and the key, the check being actuated by the jack, and the latte
being operated directly by the key, substantially as described.
11. The combination of the hammer-head, its extension, the jack and the hammer
check, the latter being arranged to be operated by the jack; substantially
described.
12. The combination of the hammer-check rail and the rail H, the hammer-head
with its extension, the jack, and the hammer-check rod sliding in bearings in the rail
and operated by the jack substantially as described.
Thated this 92nd day of July 1890.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.