APPARATUS TO BE EMPLOYED IN SUBSTITUTION FOR THE WREST PINS WHICH SERVE TO STRETCH THE CHORDS OF PIANOS
Year: 1884

page_text: COMPLETE SPECIFICATION,
We JOSEPH VIVIER of Brussels in the Kingdom of Belgium Gentleman and JEAN
OOR of Brussels in the Kingdom of Belgium Manufacturer do hereby declare the
nature of our said invention for "APPARATUS TO BE EMPLOYED IN SUBSTITUTION
FOR THE WREST PINS WHICH SERVE TO STRETCH THE CHORDS OF PIANOS" and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This Invention has for its object substituting for the tension of the chords in
pianos and in place of the wrest pins heretofore employed for that purpose a tension
arrangement acting upon the chords by direct traction obtained by means of a nut
in place of the winding action of the ordinary wrest pins and thereby obviating
the numerous disadvantages attending the use of the latter. This new system of
tension possesses this great advantage over the old arrangement that it enables
infinitely small elongations or shortenings of the chords to be obtained by a slight
effort of the hand so as to enable the tone to be regulated or adjusted with an
absolute precision which is unattainable with adjustment by turning wrest pins
which require a strong effort of the band and only allow an approximato adjustment
of the chords.
A specimen of the tension arrangement forming the object of this Invention is
illustrated in the drawing annexed to this Specification wherein the same letters of
reference indicate the same parts in all the figures.
"
Figure 1 is a transverse section of the arrangement.
Figure 2 is a partial front elevation.
Figure 3 is a part of the arrangement viewed from above.
Figure 4 is a plan drawn to a larger scale (full size) of the guide-plate arranged
for the mode of fastening which it is preferred to employ.
Figures 5 and 6 are transverse sections of the same.
Figure 7 is a plan of a guide plate arranged for another arrangement of
fastening.
•
Figures 8 and 9 are transverse sections of the same.
Figures 10 and 11 are views and sections of the screws employed for the first
arrangement of fastening.

page_text: Figures 12, 13 and 14 are views and sections of tension screws for the second
arrangement of fastening.
Figures 15, and 10 are a section and an elevation of the tension nut, and
Figure 17 illustrates the application of the system to the tension of oblique
chords.
The system consists in attaching the chords in a suitable manner to tension
screws of special and varying form enabling the chords to be arranged in the
requisite proximity to one another and the tension screws to be suitably adjusted
in a metal support or wrest plank fixed at the upper part of the framework of the
piano and in which the screws can be raised or lowered by means of suitable nuts.
The tension screws V are threaded rods having square prolongations or shanks
as illustrated in figures 11, 13 and 14, or enlarged prolongations as indicated in
figures 10 and 12, but always of the same narrow form in order to admit of the
chords being brought sufficiently near together.
There are two modes of attaching the chords; the indicated in the drawing first
mode (which is preferable) consists in making two holes in the lower ends of the
Ecrews and passing the wire through these holes causing it to take four turns upon
the shank thus rendering it impossible for the wire to slip from the screw when
stretched.
The second mode consists in providing in a suitable manner upon the lower
extremities of the tension screws, knobs or studs for the reception of eyes or loops
formed by bending and twisting the upper ends of the wires as indicated in
figures 12, 13 and 14.
The tension nuts Q which are applied to the screws for stretching the chords in
the manner indicated in figure 15 are of a height proportioned to the travel of the
screw and their upper part is fashioned like the head of a wrest pin (figure 16) in
order that it may be turned by a suitable key. A small hole is provided at the
upper part for the free escape of air which would be compressed by the end of the
BCICw.
The
The support which is of the same length as the key board is composed of a
supporting plate A to which is connected parallel thereunto a guide plate B
arranged at a distance determined by the height of distance pieces C, and
corresponding with the 'extent of motion allowed for the tension screws.
plate A, the plate B, and the distance pieces C, (which in the example illustrated
are constituted by flat bars in one piece) may be connected together by screws or
rivets, passing through the plates and the distance pieces (figure 1). The distance
pieces may also be rolled in one with the supporting plate or again may simply
consist of short tubes distributed at suitable intervals between the plates.
The supporting plate A of suitable width is firmly secured to the frame by strong
bolts or screws p and in such manner that the internal distance piece bears against
the frame at the upper edge of a metal plate D firmly secured to the latter by
Ecrews or by other suitable means immediately above the sounding board; the
plate D carries a projecting bridge S and is provided with tapped holes for
adjusting the counter bridge S. This plate may be dispensed with, the wood of
the frame in this case being made of the requisite form.
The supporting plate is perforated at the part projecting over the bed or frame
with three parallel series of holes regularly.arranged which receive the threaded
portion of the tension screws V. This arrangement of the tension screws in three
rows is necessary in order that the requisite space for the application of a key to
the nuts may be provided between the latter (figure 3). It is on account of this
arrangement that the prolongations of the tension screws in either mode of fastening
have to be made altornately wide or simply square in order that the points of
connection with the wires may be brought as nearly as possible into one vertical
plane, the prolongations or shanks of the tension screws being guided in openings
orresponding to their sectional form punched out in the guide plate B and facing
the holes in the supporting plate or wrest plank A.

page_text: a.
In the cas of the first method of fastening and for a noto requiring three wires
two wide or fat shanked tension screws are employed to every square shanked
screw, this arr. -ement is illustrated in Figure 4 which shews the three chords a, b, c
attached to thei sective tension screws in the same plane the distance between
each two three ch otes being only equal to the thickness of a shank. When
the second mode oi ing is adopted each wide shanked screw is combined with
two square shanke.
This arrangement although equally good is less
symmetrical; it is ilk in figure 7 and the connecting studs corresponding
with the chords or wire. care represented in their different positions by dotted
lines.
The number of holes in the support or wrest plank and guide plate is naturally
the same as the number of wires and decreases with the latter, thus for a note to be
rendered by two wires there would only be the holes a and b or a and c with the
corresponding tension screws and for notes with one chord the square shank screw
at a would be sufficient. The whole of the chords are supported on the bridge or
sill S in the usual manner and maintained by the counter sill S¹. The chords are
arranged in the piano in the usual manner by hooking the lower ends of the wires
over a pin firmly fixed in the wood of the piano and drawing it over the bridge
crossing the sound board, but at the upper end before the nut is put over the
tension screw to which the upper end of the chord is attached and which is
introduced into the wrest plank from below, that is to say, through the guide plate,
the slack of the chord should be taken up by means of pincers, levers or other
suitable devices in order that there may be no unnecessary work for the nut to do
in effecting the desired tension which is then exerted throughout the whole length
of the wire. When all the nuts Q provided with small washers are put on the
wrest plank and present the same appearance as the heads of ordinary wrest pins
the whole may be covered with a removable sheet metal case L (Figure 12) in order
to protect the whole from dust and damp. All the metal parts are preferably nickel
plated in order to protect them from rust..
When the Invention is applied to pianos with oblique chords the same arrangement
is employed, the chord being carried down vertically to a certain suitable point
where one or more guide pins F F (Figure 17) are inserted. In the case of grand
pianos the same arrangements are employed in a horizontal position but in such a
manner that the wrest plank shall not impede the movement of the mechanism
connected with the keys and the protecting case L is placed in the front of the
piano. It will now be readily understood that by means of this system the diapason
of a piano may be raised or lowered at pleasure and with precision by a half tone or
more without causing any injurious effect upon the instrument which moreover is
not liable to get out of tone owing to the wearing away of the wood by the wrest
pins and there is no occasion to employ a special kind of wood for fitting the latter.
By means of the tension screws herein before described which act as micrometer
screws and enable an infinitely small lengthening or shortening of the chords to be
effected, the nature of the sound of the instrument inay also be changed at pleasure
by substituting for the steel wires other wires of different metals; or gut chords or
chords of spun silk may be employed, thereby imparting to the piano a quality of
tone resembling that of a harp.
Having thus described the nature of our Invention and the manner of carrying it
out in practice what we claim is :-
First: In pianos of all descriptions adjusting the tension of the chords by a
direct acting tension arrangement with nuts in the place of the ordinary system of
traction by wrest pins substantially as hereinbefore described.
Second: In a piano in which the tension of the chords is obtained by mechanism
with nuts acting by direct traction the employment of (a). The combination with
the frame or woodwork of the piano of a metallic support or wrest plank composed.
of the supporting plate A, the guide plate B, and the distance pieces C substantially
as herein before described and illustrated in Figures 1, 2, and 3 of the annexed

page_text: drawing (b). The combination with the said support of tension screws V having
special shanks of a variable shape, and of their nuts Q, the shanks being so arranged
that the wires may be brought near together while the nuts are at a sufficient
distance apart for the application of a key thereon, substantially as bereinbefore
described and illustrated in Figures 1, 2 and 3 of the annexed Drawings-(c). In
the tension screws V the employment in a special manner of holes and studs for the
purpose of attaching the wires thereunto all substantially as hereinbefore described
and illustrated in Figures 10, 11, 12, 13 and 14 of the accompanying drawings.