Year: 1887

page_text: Date of Application, 26th May, 1887.
Specification Accepted. 28th June, 1887,
I ANDREA LUIGI CALDERA of 39 Rue de Po, Turin, in the Kingdom of Italy,
Engineer, do hereby 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:-
This Invention relates to an improved key-board musical instrument producing
tones having the characteristic quality of those of the harp but fuller, richer, and
more sustained, the volume of tone approaching that of a pianoforte and being capable
of as much variation or gradation. The body or frame of this new instrument
approaches in outline that of a harp, but the strings which are metallic, are parallel
to the sound board as in a pianoforte and are played upon in much the same way, the
action being, however, of special construction as hereinafter described.
Many attempts have been made to produce such an instrument, but without
practical result, the failure being due to the fact that the plectrum or organ by which
the strings are twanged or plucked has always been actuated directly by the keys
without any provision for assisting the players' fingers to overcome the resistance of
the strings to deflection, and as the strings are of different lengths and have
consequently different degrees of tension and flexibility, each key had necessarily to
be struck or depressed with a different degree of force according to the length of the
string to be vibrated. Such instruments were consequently of no practical utility
especially as the keys could not be moved with the ease and rapidity essential to the
performance of a musical composition.
In the improved instrument of this invention, the key is depressed by the finger as
in playing the pianoforte and the string acted on by a plectrum or organ which is
designed to produce the effect of the human finger upon the string of the ordinary
harp, and with the action or operative mechanism of which is combined a weighted
arm whereby power is stored up during one part of the motion of the key and given
out at another, so as to equalize the motion and ensure sufficient pressure of the
plectrum against, and its rapid escape from, the string.
Reference is to be had to the accompanying drawings forming part of this
specification wherein figure 1 is a face view of the sound board and frame. Figure 2 is a
vertical section on line 1-1; and figure 3 is a horizontal section on line 2-2.

page_text: Figure 4 is a cross-section of the action (full size). Figure 5 is a similar view of
part of the same, drawn twice full size. Figure 6 is a face view of the action for one
note; and figure 7 is a plan of the action for two notes, the parts being in different
positions for the two notes. The same letters of reference indicate the same parts in
all the figures.
The frame of the instrument comprises the wrest plank A (in shape somewhat
resembling the neck of a harp) supported by wood bracings B B at the bass end and
middle of the instrument, rising from the lower cross bar C; a third short bracing B'
connecting the end of the wrest plank to a diagonal piece D which is connected at
its other end to the lower end of the bracing B¹. The bracings B B¹ are connected
by a cross bracing E. The sound board F somewhat resembles that of an upright
piano although differing therefrom in many respects. It has resonance holes e and
is barred, as represented in dotted lines; it passes the wooden plate 6 forming part
of the bracing B and terminates at the plate & glued to B. G is the belly bridge on
which bear, as in a pianoforte, the strings connected to the hitch-pin plate e and to
the wrest pins. To avoid confusion, only the strings corresponding to the seven
octaves of the note "F" have been represented by broken lines. The curve of the
belly bridge is continuous-i.e. without breaks or angles-and is necessarily in
correlation with the curve passing through the centres of the wrest plank bridge
studs. F¹ is a second sound board forming the back of the sound chamber of the
instrument.
The line on which the strings are acted on by the mechanical fingers or plectra of
the action is also represented by the line 2-2. This line intersects the strings S at
a certain proportion of their length, (in the same way as in the pianoforte the "strike"
line or line of percussion of the hammers is at a certain fraction of the length of the
string in vibration) but in order to obtain the characteristic quality of tone of the
ordinary harp, and to enable the string to have sufficient flexibility to allow it to
yield under the pressure of the mechanical finger or plectrum, the situation of this
line is very different to that in the piano. Measured on the first "F" in the bass it
is situated at nine thirteenths of the length of string in vibration, reckoning from
the wrest plank bridge. From this point towards the treble, it gradually approaches
the middle of the strings until, on reaching the sixtieth string or the fifth octave, it
will be just at mid length of the string at which proportion it remains for the higher
notes. The position of this line is very important, and is in fact essential to the
success of the new instrument, and although I have thus specified the best position
with considerable accuracy, I do not absolutely limit myself thereto, as some variation
is allowable say between the middle and two thirds the length of the string measured
on the first bass string.
The preferred form of the curves to be given to the line of centres of the wrest
plank bridge studs and to the belly bridge, which are necessarily in correlation to
each other, is graphically represented in figure 1. The belly bridge is fixed upon
the sound board at its mid height, so that throughout the whole of the instrument
there is as large an area of sound board above as below the bridge; this is important
in order to obtain a uniformly sweet and harmonious tone throughout the whole scale
of the instrument.
The instrument is a monochord-that is to say each note is produced by the
vibration of a single string, as in a harp; but the strings as before mentioned, are
metallic like those of a piano, instead of being of catgut. This instrument therefore
stands much better in tune than an ordinary harp. It is preferred that the strings
should be about the same length but of half the diameter and consequently have a
quarter of the tension of the corresponding strings of an ordinary upright
pianoforte.
The action whereby the "pizzicato" or twanging effect of the harp is produced, is
illustrated in figures 4 to 7. The key-board is similar to that of a pianoforte. The
key H acts through a sticker I upon an elbow lever K pivoted to a support Z fixed
on the rail Y. To the upper member of the elbow lever K is jointed a jack L in the
forked end of which is pivoted an elbow lever M which carries a head N which acts

page_text: directly on the string S as does the finger of a harpist, and which I therefore term a
finger. The jack L is also supported by a radius link O constituted by a piece of
wire whose ends (bent at right angles) are received in bushed holes in the parts L
and Z. It forms with the said upper member of the lever K, a sort of parallel motion
whereby the jack L is guided to and fro, in an approximately straight line
perpendicular to the string. The elbow lever M is pivoted on a centre m which is
parallel to the string S and the finger N is connected thereto, so that it can yield
under a sudden pressure. For this purpose it has a cloth bushed hole which fits and
slides upon a pin
n carried by the elbow lever M, the finger N being connected to
the lever M and forced outwards by a bow spring n². To the other or laterally
projecting arm of lever M is connected a cross-head M¹ to the upper end of which is
connected a flexible tape or tie P which extends rearwards and whose other end is
attached to a spring p fixed adjustably to the rear rail U. The purpose of this tie,
which I term the " escapement tie," is to produce a lateral motion of the finger after
it has been moved towards and caused to press sufficiently against the string S.
This lateral motion of the finger is produced by the tie P arresting the laterally
projecting arm of the elbow lever M in its forward movement, whilst its centre of
motion m continues to move towards the string, whereby the lever M and finger N
are caused to pivot on centre m, the finger N thus slipping from in front of the string
by a motion approximately at right angles to its forward motion. The elasticity of
the spring p permits of the finger N causing the string S to vibrate to a greater
extent before it escapes therefrom when the key is depressed more suddenly, and
thus musical expression is obtained. The finger having thus escaped from the string
the latter is thus left free to vibrate, as shewn at the upper part of Figure 7. This
figure represents two of the fingers N, the one at the lower part of the figure in
the normal position of rest and the one at the upper part of the figure in the escaped
position wherein it remains after pressing against and vibrating a string, so long. as.
the key is kept down.
To the lower end of the same cross-head of lever M is connected another tie Q,
which I term the "counter escapement tie" and whose other end is connected to a
spring 9; the purpose of this tie, which comes into action just before the finger N and
jack L completes their return movement, being to return the finger to its normal
position, shewn in the lower part of figure 7, the finger remaining in the inclined
position until the tie Q comes into action. q is a wire stop to limit the motion of
spring 9. are wire stops limiting the motion of the piece M N. They are fixed
in place by a plate R and screw.
It will be observed that the stop r altogether prevents the lateral deflection of the
finger in one direction, and that the string S is towards the same side of the centre
line passing through the centre of motion m so that the finger when moved forward
and pressed against the string, is quite rigid on its centre and bears against the string
with a direct thrust, and has no tendency to escape from the string until the escape-
ment tie P comes into operation, the joint of the plectrum or finger thus resembling
a knee-joint.
The finger N is faced with felt N' (made of rabbits' wool, beaver, or other fine
wool, like that of which soft felt hats are made) which is bevelled at an acute angle at
the side where it quits the string, and overhangs or extends slightly beyond the finger N
which is itself undercut so as to leave clearance for the string to vibrate. The
elasticity of the mechanical finger N obtained by the spring n², enables the player to
modify the intensity of the sounds produced and permits of obtaining all the effects
of light and shade and of musical expression obtainable upon the pianoforte. This
elasticity of the fingers N is, moreover, absolutely essential especially in the case of
the upper three octaves, the strings of which have not sufficient flexibility to
enable them to yield under the pressure of the finger N far enough to permit the
lateral deviation or escapement of the finger which is indispensable for the vibration
of the string.
In the elbow lever K is fixed a lever arm which carries a lead weight T which
fulfils the function of a fly-wheel-that is to say-it stores up power at the beginning

page_text: of the movement and gives it out when the finger N is resisted by the string S, so
equalizing the touch at all positions of the key. The radius of the arm carrying said
weight is about five times that of the other arm of the lever K to which the jack L is
jointed, and therefore the distance moved through by the weight is correspondingly
greater than that moved through in the same time, by the finger N which in fact 5
moves through only about half the distance moved through by the front end of the
key H when depressed by the player. The finger N is therefore pressed against
the string with considerable energy owing to the momentum or stored power of the
weighted arm T, so that the forward motion of the finger is not checked on meeting
the resistance of the string S and the rapid escapement of the finger from the string
is thereby ensured.
The motion of the weighted arm T is cushioned by a spring t fixed to the rail U
with which spring it comes in contact, after the finger N has escaped from the string S
and whereby the weighted arm is thrown down quickly and all the parts of the
action returned rapidly to the normal position, thereby enabling a good repetition
action to be obtained.
The centres of the various parts of the action are bushed with cloth, as usual in
pianoforte actions, and the abutting faces of the different members of the action are
faced with cloth or felt to prevent noise, as indicated by the letter c.
The instrument is provided with dampers V, like those of a pianoforte, each carried
by a spring v attached to a rail W mounted between the strings S and the sound
board and journaled at the ends to permit of all the dampers being removed from the
strings in sustained or fortissimo passages, this movement being effected by means of
a pedal, as in a piano. Each individual damper is raised by the corresponding key
through the agency of an elbow lever X acting on the damper in order to permit the
string to vibrate, so long as that particular key is held down.
The action is mounted on a rail Y united by end pieces to the rail U and
pianissimo effects are obtained by retracting the action slightly from the strings by
means of another pedal, so that when a key is depressed the corresponding finger N
will be pressed very lightly against the string, and a correspondingly weak sound will a
be produced.
In the instrument herein described, the fingers push the strings towards the sound
board but it will be evident that by making the fingers hook-shaped, the action might
be so arranged as that the strings will be pulled or acted on in the opposite direction.
It will be obvious, that with but a slight modification, the same action would serve
for a horizontal instrument analogous to a horizontal pianoforte.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, I declare that what I claim is;
1. The herein described keyboard played harp, constructed and operating sub-
stantially as specified.
2. A key-board stringed instrument in which the string is vibrated by a plectrum
or mechanical finger moving in two directions, the one towards the string at right
angles thereto and to the acting face of the plectrum or finger, and the other away
from the string in a direction approximately at right angles to the first, substantially
as specified.
3. A key-board stringed instrument in which the string is vibrated by the direct
thrust of a knee jointed plectrum or mechanical finger whose pivotal centre is parallel
to the string, the said centre receiving a motion towards the string, and the finger or
plectrum (after being so moved forward to deflect the string) receiving an oscillating
inotion on its centre, as specified.
4. In a key-board stringed instrument in which the string is vibrated by the direct
thrust of a plectrum or finger moving in two directions as herein described; the
combination with the said plectrum or finger, of a weighted arın acting as a store of
power to overcome the resistance of the string to the motion of the plectrum or finger
and as a means of quickly returning the "action" to the normal position after the
string has been vibrated, substantially as specified.

page_text: 5. In a keyboard stringed instrument, the combination of the finger N, the pivoted
arm M, the guide pin n and the spring n³ connecting the finger N and arm M and
forcing the former forwards with an elastic or yielding pressure, substantially as and
for the purpose specified.
6. In a keyboard stringed instrument, the combination with the yielding finger N
and the elbow lever M pivoted on a centre parallel to the string in a jack L having
a motion perpendicular to the string, of the stop r on the jack for preventing the
oscillation of the finger in one direction, the tie P for producing the oscillation of the
finger in the opposite direction on its forward motion, and the tie Q for restoring it
to its normal position on its return, as described.
7. In a keyboard stringed instrument, the combination with the yielding or spring
finger N, the elbow lever M carrying the same pivoted in a jack L, of the lever K
and radius link O for producing the longitudinal parallel motion of jack L, as
specified.
8. In a key-board stringed instrument, the combination, substantially as herein
specified, of the spring finger N, elbow lever M carrying the same and pivoted in a
jack L, ties P, Q, controlling the elbow lever, radius link O, and lever K. guiding and
actuating the jack L, and the weighted arm T acting as a store of power, as
described.
9. In a key-board stringed instrument, the combination, substantially as herein
specified, of the spring finger N, elbow lever M carrying the same and pivoted in a
jack L, ties PQ controlling the elbow lever, radius link O, and lever K guiding and
actuating the jack L, the weighted arm T acting as a store of power, and the spring t
acting as a cushion for the weight T and assisting it to return the action quickly to
the normal position, as described.
10. In a key-board stringed instrument, the combination with the spring plectrum
or finger pivoted on a centre parallel to the string supported in a jack moving in a
direction perpendicular to the string and with the tapes for oscillating the finger on
its centre, of the springs p and q for imparting elasticity to the action of the tapes,
as specified.
11. In a key board stringed instrument, a knee jointed mechanical finger or
plectrumn acting on the string as described, and having an acting face of felt bevelled
to an acute angle and projecting substantially as shewn and described.
Til
1
M
1000
A. L. CALDERA.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.