Year: 1888

page_text: Date of Application, 31st July, 1888
Complete Specification Left, 29th Nov., 1888
Complete Specification Accepted, 15th Jan., 1889.
1, ANDREA LUIGI CALDERA, of Turin, Italy, and at present of 30, Lillie Road,
Brompton, in the County of Middlesex, Engineer, do hereby declare the nature of this
invention to be as follows:-
My Invention' relates to improvements in the key-board harp forming the subject of
former Letters Patent granted to me and dated the 26th day of May 1887, No. 7,685;
and it has first for its object to lighten the touch and to simplify and otherwise
improve the construction of the action or mechanism by which the plectra or mechanical
fingers are caused to act on the strings ;-secondly to improve the quality and volume
of the tone produced by the instrument particularly in the lower register for which a
special percussive action, different to that used for the remainder of the instrument; is
provided; and thirdly to enable the quality of the tone to be modified at the will of the
performer.
In order to simplify the construction and increase the durability of the action and,
by rendering it more independent of climatic influences, ensure greater precision and
more constant uniformity of touch, I dispense with the escapement and counter-
escapement ties or tapes and their coiled springs referred to in my previous patent and
cause the plectrum or finger to be acted on directly by a steel spring; and in order to
lighten the touch of the instrument, I dispense with the spring connection between the
acting head of the plectrum and the pivoted shank or body by which it is connected,
and to enable the plectrum or finger to quit, or escape from, the string with the
necessary facility after having pressed against, and deflected, the string, the acting
face of the plectrum instead of being perpendicular in the direction of its width to the
line of motion of the plectrum, is bevelled in such direction as to enable it to slip
more readily off the string in the act of twanging or plucking it, the angle to which it
is so bevelled being such that the plectrum shall not slip off prematurely but only
after having deflected the string to a sufficient extent and then only under the action of
the escapement spring.
.

page_text: I
In order to increase the volume of tone in the lower or bass register, I provide for
this part of the instrument an action somewhat similar to that of a pianoforte by which
the strings are struck percussively instead of being twanged or plucked, this
action being however, of special construction and acting on the strings at a
different point in their length to that at which the strings of a pianoforte are
struck.
In order to enable the quality of the tone to be modified at will and caused to
approximate more or less nearly to that of a harp, as may be required, a manual or
pedal operated "mute" or sourdine, is provided which acts on the strings at a point
immediately adjacent to the sound-board bridge.
The instrument, as in the former case, is a monochord, there being one string to
each note, these strings being of metal wire of about two-thirds the diameter (at the
middle register) to about half the diameter (in the upper register) of the corresponding
strings of an ordinary upright pianoforte, for instance, the No. 8 wire is preferably
employed for the highest notes, and No. 13 at the middle register.
The acting head of the plectrum or mechanical finger which acts on the string is affixed
rigidly by a screw-wire in the body portion. This body portion is pivoted on a centre
pin which is vertical or parallel to the string this centre being carried by the jack.
This body portion is virtually an elbow lever, one arm of the lever being formed by a
pair of laterally projecting pins or abutments between which plays a steel spring fixed
to the fork, this spring being reinforced in the direction in which it effects the
escapement of the plectrum from the string, by a stiff rod standing up behind it for
part of its length. The motion of the body part in the two directions is limited by
wire stops, and it is held down in its place on the centre by a wire catch. The acting
face of the plectrum is bevelled at an incline of about 1 in 4 from the perpendicular
to the direction of its motion.
The distance between the abutments is proportional to the stiffness of the spring and
to the amount of rectilinear motion of the plectrum necessary to cause it to deflect the
string and effect its escapement therefrom. The one abutment may be termed the
escapement abutment, and-the-other abutment the counter-escapement abutment. In
the normal position of the action, the spring presses lightly against the counter-
escapement abutment and holds the plectrum in position in readiness to act on, and
deflect, the string by a direct thrust against it. At the proper momont after the
plectrum has partially deflected the string, the escapement abutinent comes in contact
with the spring which being stiffened or reinforced by the rod opposes sufficient
resistance to the abutment to cause the plectrum to move laterally with a rubbing
action against the deflected string and thereby to effect its escape therefrom. On the
release of the key, the plectrum returns towards its position of rest and in so returning
after having passed clear of the string, the counter-escapement abutment meets the
spring which is less stiff in this direction than in the other and by it returned into
line with the string in readiness to act on it again with a direct thrust when the key is
again depressed.
The damper is carried by an elbow lever acted on by the key and is pressed by a
spring against the string.
The mute or sourdino, is a cloth or felt covered bar conforming in shape to the outline
of the bridge immediately above which it is placed, and it is operated in one direction
by a pedal or knee motion suitably connected thereto at numerous points in its length,
as will be readily understood, and in the other direction by springs. This mute
presses against the vibrating portion of the strings at a point close against the belly
bridge and, unlike the dampers, it is not removed from the string when the latter is
put in vibration whereby the quality of tone of the metal strings is caused to
approximate more nearly to that of the cat-gut strings of the ordinary harp. In its
normal position, the mute is held away from the strings, a more metallic quality of
tone being then produced.
The various centres and contact surfaces of the parts of the action, are bushed or
faced with cloth as usual in such actions, and the acting face of the plectrum is clothed
with felt of a very fine and compact quality such as used for "wideawake" felt hats.

page_text: In the part of the action which corresponds to the lower bass register the plectrum
is replaced by a hammer similar to that of an ordinary pianoforte whereby a far more
powerful tone may be obtained than with a plectrum, the point at which the string is
struck causing the tone however, to partake of the harp quality, as hereafter described.
The hammer has no escapement as in that of the pianoforte but the hammer butt is
centred to a jack or lever centred at in a fork fixed to the rail. The hammer butt has
a tail piece which is loosely connected by a wire and stop with the jack lever in such
a way that the hammer is permitted a limited amount of play or motion independent
of the jack. The key acts directly on the hammer through the lifter and jack which
has a rounded part on which the lifter acts, and the head of the hammer is weighted to
enable it to strike the spring with sufficient force by its own momentum after the key
ceases to act on it, a check spring fixed to the rail acting on the hammer head for the
purpose of preventing the hammer rebounding and striking a second blow, a recoil
spring being also provided by which the jack, and consequently the hammer, is drawn
downwards when the key is released.
.
The belly-bridge is in correlation with the curved line passing through the wrest-
plank bridge studs, but instead of being continuous it is made in two portions, the
bass strings passing over the one part being struck by the hammers above described..
The "strike" line of both the hammers and the plectra or fingers, is a continuous straight
line across the strings parallel to the key-board, but its proportional distance from the
belly-bridge is different for the bass strings, and hence the break in the belly
bridge.
In order to conserve the harp-like quality of tone in the lower register, notwith-
standing the use of a percussive action, the "strike" line or line of percussion of the
hammers is situated for the lowest "A" in the bass at four-thirteenths of the length
of string in vibration reckoning from the belly bridge. From this point upwards in
the scale, the proportions are gradually varied until” at the third "A" of the bass the
"strike" line is situated at one fourth of the length of the string. For the lowest
string acted on by the plectra, the "strike" line is situated at one-third the length of
the string, and from this point towards the treble, it gradually approaches the middle
of the strings until on reaching the sixth "A" from tho bass it is at about mid length
of the string, at which point it remains for the higher notes. The bass strings
struck by the hammers along the "strike" line above indicated, yield soft and
mellow tones partaking of the characteristic quality of those of the ordinary harp.
by reason that the harmonic and overtones which accompany the primary tones
approximate more nearly to the latter and produce a less metallic sound than when
the string is struck, as in the pianoforte, at a comparatively short distance from the
wrest plank.
A. L. CALDERA.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: I, ANDREA LUIGI CALDERA, of Turin, Italy, and at present of 30, Lillie Road,
Brompton, in the County of Middlesex, 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:-
My Invention relates to improvements in the key-board harp forming the subject
of former Letters Patent granted to me and dated the 26th day of May 1887,
No. 7,685 and it has first for its object to lighten the touch and to simplify and
otherwise improve the construction of the action or mechanism by which the plectra
or mechanical fingers are caused to act on the strings ;-secondly to improve the
quality and volume of the tone produced by the instrument particularly in the
lower register for which a special percussive action, different to that used for
the remainder of the instrument, is provided ;-and thirdly to enable the quality of
the tone to be modified at the will of the performer.
In order to simplify the construction and increase the durability of the action
and, by rendering it more independent of climatic influences, ensure greater precision
and more constant uniformity of touch, I dispense with the escapement and counter-
escapement ties or tapes and their coiled springs referred to in the specification of my
previous patent and cause the plectrum or finger to be acted on directly by a steel
spring; and in order to lighten the touch of the instrument, I dispense with the spring
connection between the acting head of the plectrum and the pivoted shank or body by
which it is connected, and to enable the plectrum or finger to quit, or escape from, the
string with the necessary facility after having pressed against, and deflected, the
string, the acting face of the plectrum instead of being perpendicular in the direction
of its width to the line of motion of the plectrum, is bevelled in such direction
as to enable it to slip more readily off the string in the act of twanging or plucking
it, the angle to which it is so bevelled being such that the plectrum shall not
slipp off prematurely but only after having deflected the string to a sufficient extent
and then only under the action of the escapement spring.
In order to increase the volume of tone in the lower or bass register, I provide
for this part of the instrument an action somewhat similar to that of a pianoforte
by which the strings are struck percussively instead of being twanged or plucked,
this action being however, of special construction and acting on the strings at a
different point in their length to that at which the strings of a pianoforte are
struck.
In order to enable the quality of the tone to be modified at will and caused to
approximate more or less nearly to that of a harp, as may be required, a manual
or pedal operated "mute" or sourdine, is provided which acts on the strings at
point immediately adjacent to the sound-board bridge.
Reference is to be had to the accompanying drawings forming part of this
specification, wherein figure 1 is a cross-section of the action, full size; figure 2 is
a similar view; and figure 3 a plan of the same, on an enlarged scale, the latter

page_text: figuro showing two of the plectra in different positions. Figuro 4 is a cross-
section of the action for the lower bass register; and figure is a face view of
the sound-board and frame. The same letters of reference indicate like parts in all
the figures.
The instrument, as in the former case, is a monochord, there being one string
to each note, these strings being of metal wire of about two-thirds the diameter
(at the middle register), to about half the diameter (in the upper register) of the
corresponding strings of an ordinary upright pianoforto; for instance, the No. 8
wire is preferably employed for the highest notes, and No. 13 at the middle
register.
A is the rail on which the action is mounted, B is the key, the sticker jointed
at e to an elbow lever D pivoted at d in a fork E fixed on rail A. F is what I
term the jack, jointed at f to the elbow lever D and connected by a radius link G
with the fork E, the centres of motion d, f, and g g¹, being equidistant so that
the jack receives a nearly parallel motion. H is a weighted arm fixed to the elbow
lever D for the purpose of equalizing by its is civa, the movement of the action
and assisting the finger to overcome the resistance of the string $ to deflection
from a straight line. I is a steel spring to cushion this weighted arm on arriving at.
the end of its motion. All the above mentioned parts are substantially similar to those
described in my former patent.
K, L, is the plectrum or mechanical finger which acts on the string S, K being
the acting head affixed rigidly by a screw-wire k in the body portion L. This body
portion is pivoted on a centre pin which is vertical or parallel to the string S, this
centre being carried by the jack F. This body portion L is virtually an elbow
lever, one arm of the lever being formed by a pair of laterally projecting pins or
abutments m m between which plays a steel spring M fixed to the fork E this spring
being reinforced in the direction in which it effects the escapement of the plectrum
from the string, by a stiff rod m² standing up behind it for part of its length.
The motion of the part L in the two directions is limited by wire stops n
it is held down in its place on the centre by a wire catch ². The acting face of the
plectrum is bevelled at an incline of about 1 in 4 from the perpendicular to the direction
of its motion.
n¹, and
The distance between the abutments m m is proportional to the stiffness of the
spring and to the amount of rectilinear motion of the plectrum necessary to cause
it to deflect the string and effect its escapement therefrom. The abutment m may
be termed the escapement abutment, and the other abutment m the counter-escape-
ment abutment. In the normal position of the action, the spring presses lightly
against the counter-escapement abutment m' and holds the plectrum in the position
shown in the lower part of figure 3, in readiness to act on, and deflect, the string by a
direct thrust against it. At the proper moment after the plectrum has partially
deflected the string, the escapement abutment m comes in contact with the spring
which being stiffened or reinforced by the rod m² opposes sufficient resistance to
the abutment m to cause the plectrum to move laterally with a rubbing action
against the deflected string and thereby to effect its escape therefrom. On the
release of the key, the plectrum returns towards its position of rest and in so
returning after having passed clear of the string, the counter-escapement abutment m'
meets the spring which is less stiff in this direction than in the other and is by it
returned into line with the string in readiness to act on it again with a direct thrust
when the key is again depressed.
The damper O is carried by an
by a spring p against the string.
bridge.
elbow lever P acted on by the key and is pressed
R is the belly or sound board, and T the belly-
U is the mute or sourdine, being a cloth or felt covered bar conforming in shape
to the outline of the bridge T immediately above which it is placed, as shewn in
figure 5, and operated in one direction by a pedal or knee motion suitably connected
thereto at numerous points in its length, as will be readily understood, and in the
other direction by springs. This mute presses against the vibrating portion of the

page_text: strings at a point close against the belly bridge and, unlike the dampers, it is not
removed from the string when the latter is put in vibration whereby the quality of
tone of the metal strings is caused to approximate more nearly to that of the cat-
gut strings of the ordinary harp. In its normal position, the mute is held
away from the strings, a more metallic quality of tone being then produced.
The various centres and contact surfaces of the parts of the action, are bushed
or faced with cloth as usual in such actions, and the acting face of the plectrum is
clothed with felt of a very fine and compact quality such as used for "wideawake
felt hats.
"
Referring to figure 4, in which the same letters of reference indicate the same
parts as in the previous figures, it will be seen that the plectrum is replaced by a
hammer similar to that of an ordinary pianoforte whereby a far more powerful
tone may be obtained than with a plectrum, the point at which the string is
struck causing the tone however, to partake of the harp quality, as hereafter
described. The hammer, it will be observed, has no escapement as in that of the
pianoforte but the hammer butt is centred at v to a jack or lever W centred at w
in a fork fixed to the rail A. The hammer butt has a tail piece which is
loosely connected by a wire and stop y with the jack lever W in such a way that
the hammer is permitted a limited amount of play or motion independent of the
jack. The key B acts directly on the hammer through the lifter and jack W
which has a rounded part on which the lifter acts, and the head of the hammer
is weighted at to enable it to strike the string with sufficient force by its own
momentum after the key ceases to act on it. Vis a check spring fixed to the
rail and acting on the hammer head for the purpose of preventing the hammer
rebounding and striking a second blow. W₁ is a recoil spring by which the jack,
and consequently the hammer, is drawn downwards when the key is released.
Referring to figure 5, it will be observed that the belly-bridge T is in correlation
with the curved line passing through the wrest-plank bridge studs, but instead of
being continuous it is made in two portions T T, the bass strings passing over
the part T being struck by the hammers-illustrated in figure 4. In figure 5 only
the octave strings corresponding to the notes "A" are shown. It will be observed
that the "strike" line zz of both the hammers and the plectra or fingers, is a
continuous straight line across the strings parallel to the key-board, but its propor-
tional distance from the belly-bridge is different for the bass strings, and hence the
break in the belly bridge.
In order to conserve the harp-like quality of tone in the lower register, not-
withstanding the use of a percussive action, the "striko" linozor line of-percussion
of the hammers is situated for the lowest "A" in the bass at four-thirteenths of
the length of string in vibration reckoning from the belly bridge. From this point
upwards in the scale, the proportions are gradually varied until at the third "A" of
the bass the strike" line is situated at one fourth of the length of the string.
For the lowest string upon the part T of the bridge, the "strike" line is situated at
one-third the length of the string, and from this point towards the treble, it gradually
approaches the middle of the strings until on reaching the sixth "A" from the bass
it is at about mid length of the string, at which point it remains for the higher
notes. The bass strings struck by the hammers along the "strike line above
indicated, yield soft and mellow tones partaking of the characteristic quality of those of
the ordinary harp by reason that the harmonic and overtones which accompany the
primary tones approximate more nearly to the latter and produce a less metallic sound
than when the string is struck, as in the pianoforte, at a comparatively short distance
from the wrest plank.
"
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 :—
1st. In the herein described action for a key-board harp, the combination with a
mechanical finger or plectrum pivoted upon a vertical axis upon a jack receiving

page_text: motion in a direction perpendicular to the string, as described, of a leaf spring fixed
at one end and applied to act at the other end against an abutment projecting
laterally from the pivoted body of the plectrum for the purpose of effecting the
escapement of the plectrum from the string, as described.
2. In the herein described action for a key-board harp, the combination with the
mechanical finger or plectrum pivoted upon a vertical axis upon a jack receiving
motion in a direction perpendicular to the string, as described, of escapement and
counter-escapenient abutments projecting laterally from the pivoted body of the
plectrum and of a leaf spring fixed rigidly at one end and acting at the other end in
opposite directions against the said abutments, the said spring being reinforced so as
to be stiffer in one direction than the other, substantially as, and for the purpose
specified.
3. In the heroin described action for a key-board harp, the plectrum or mechanical
finger having its acting head rigidly fixed to the pivoted body or elbow lever by
which it is carried and operated, as described, and having its acting face bevelled,
as described, for the purpose of facilitating its escapement from the string.
4. In an action for a key-board harp, the combination with a lever or jack, of a
hammer centred thereon and connected thereto, as described, so as to be actuated
thereby and to have limited motion independently thereof, by virtue of its own
momentum, substantially as specified.
5. In an action for a key-board harp, the combination with the hammer and its
jack or lever connected and operating as described, of the recoil and check springs,
as specified.
6. A key-board harp in which the action acts partly by percussion and partly by
plucking the strings, the percussive portion of the action being constructed and
operating as herein specified and being applied only at the bass register whilst the
plucking part of the action is applied at the middle and upper registers, the "strike"
lines of the two parts of the action being continuous across the strings, as described.
7. The combination with a key-board harp of a mute or sourdine applied, by means
of a pedal or otherwise, against the strings in close proximity to the belly-bridge,
as described.
TAL: 20th day of November 1888.