Piano Stringing, Tuning, and String Spacing Devices.
Year: 1891

page_text: Date of Application, 7th Sept., 1891
Complete Specification Left, 7th July, 1892-Accepted, 3rd Sept., 1892
PROVISIONAL SPECIFICATION.
Piano Stringing, Tuning, and String Spacing Devices.
I ROGER BLOMLEY WATSON of 1439 Calafonia Street Denver, in the County
of Arapahoe, and State of Colorado, United States do hereby declare the nature
of my invention of devices for PIANO STRINGING, TUNING, AND STRING
SPACING, to be as follows:-
My invention relates to the stringing and tuning of pianos.
The spacing device is shown in the accompanying drawings in various forms at
C, C, C, C, and C, and its characteristics or novel features which distinguish.it
from all other devices for the same purpose is that, while capable of regulating
the upper parts of the strings to any desired distance apart, and in any desired
direction at right angles to the strings length it is not supported by, or attached
to, or even necessarily in contact with any part of the piano except the strings.
It may be made of piano string wire and is placed upon the strings in the
manner shown in the drawings and its advantages are that not being fixed in
relation to the strings it only very slightly resists their up or down motion when
they are being tuned, but not sufficiently to cause any material difference of
tension between the two parts of the string above and below it. Some device
for spacing is required in all tuning devices in which the string fastenings
thereto are arranged equally distant from each other as shown in Fig. 1; otherwise
the strings would not be grouped into sets of two, or three, where the hammers
strike them. The usual method is to pass the strings into holes or grooves formed
in the agraffe, bridge, or pressure bar, but these parts being fixed in relation to the
strings they resist their up or down motion in tuning and so cause unequal tension
of the parts of the string above and below and as this difference balances slowly
after tuning the string is again put out of tune. In the pinblock system of stringing
these devices are not usually required as the strings run parallel to each other and
are grouped into sets right up to the tuning pins. It will be seen that the spacers
may be so made and applied as to either push or draw the strings in a sideward
direction see Figs. 1 and 19, or in an inward or outward direction see Figs. 14 and 16.
In the tuning device the novel and distinguishing features are, First, As will be
seen the stringers A and A¹ shown in the drawings tend to move outward and
inward respectively at their lower parts from their desired positions shown in
Fig. 2 as the three points of contact (viz. those of the string with the agraffe E and
with the stringer, and that of the stringer with the flange G³) are not in a line with
each other. In my device the inward or outward motion of the lower parts of the
stringers or the adjacent parts of the strings is limited or prevented by means of the
plate H or its equivalent such as the plate Z or the plates B B Figs. 5 to 8, its
distinguishing feature being that it is not fixed or attached to, or necessarily in
contact with any part of the piano except the stringers or the upper parts of the
strings, this of course includes all forms of device which are capable or regulating
this inward or outward motion of the stringers without being attached to other parts
even though it may be considered desirable to attach them to other parts to serve
other purposes. All other devices in use for this purpose are attached in some way
to parts other than the stringers or strings, that is to the plate G or other adjacent
parts. It will be seen that the device may be modified and applied to the parts of
the strings just below the stringers and produce the same results although the
method shown is preferable. In Figs. 1, 2, 3, and 4 the stringers press against the
bar H which passes between the sets or rows of stringers but in Figs. 5 to 8
the plates Z or B B operate by pressing against the outside edges of the stringers

page_text: Figs. 5 and 6 show side and top views of the plate Z and the stringers modified to
suit it, and Figs 7 and 8 show forms of the stringers to suit the plates B B in top
and side views the plates being connected by bolts, the upward turned ends of the
stringers being shown darker than the screw threaded ends in Fig. 7. Second,
Lateral or twisting motion of the stringers is prevented by one part of each
stringer being guided by contact with another substantially different part of one or
more adjacent stringers as shown along the dotted lines X X of Fig. 1, but in the
bass part where the strings are not close enough together to guide each other the
pieces M and are placed upon the bar H as shown in Fig. 3, these pieces are also
shown in Figs. 10 and 11 they should grip tightly upon the bar H at their lower
parts this being effected by making these parts come somewhat closer together than
the width of the plate so that in placing them upon it these ends may be forced
apart. The bar H is also shown in Fig. 9 having grooves to guide the ends of the
stringers independent of their contact with each other a similar office is performed
by the grooves D D in Fig. 7.
Third, By placing the string windings (that is their fastenings to the stringers) in
two or more rows one behind the other and winding the strings some in an inward
and some in an outward direction, that is, to or from the plate G as shown in
Figs. 1, 2, 3, 12, and-13, I am enabled to bring the downward proceeding ends of
the strings into one line or row, or sufficiently so for practical purposes without
requiring space for more than one thickness of string between the stringers
see Fig. 13 which is taken through the dotted lines X X of Fig. 2 and in which the
dark points represent the downward proceeding parts of the strings, Fig. 2 shows
more openly the method of winding the strings In other methods either the string
fastenings are placed one above the other thus requiring greater space owing
to the greater length of some of the stringers, or they are placed beside each
other in one row and so require space for two thicknesses of strings between the
stringers so that the strings have to be very thin at this part and the bends of the
strings very sharp, which weakens both stringer and string.
Fourth, In order that a tuner may be able to see at a glance which nut operates
the string he wishes to tune, I place a distinguishing mark upon one or more
of each set of two, or of three nuts or upon the parts adjacent to them, this may
consist of any difference of color (such as a and a' Fig. 1) or any mark upon
or change of form of any of the nuts or stringers or adjacent parts (such
as a 2 Fig. 2, or a 3 Fig. 20) providing they are uniform and conspicuous
enough to serve the purpose, some such means is required in all forms of tuning
device where the nuts and stringers are arranged in uniform rows and not grouped
into sets, and the strings do not come sufficiently close to the nuts to show their
connections.
It will be understood that any of the several parts of the devices shown may
be used to produce substantially the same results, but in combination with other
forms of devices operating in a different manner.
Dated this Twenty-fourth day of August 1891.
COMPLETE SPECIFICATION.
Piano Stringing, Tuning, and String Spacing Devices.
I ROGER BLOMLEY WATSON of 1001 17th Avenue Denver in the County of
Arapahoe and State of Colorado, U.S., 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 the stringing and tuning of pianos; and its main objects
are, first, to provide a simple and efficient screw device by which the strings may
be adjusted in tension and pitch, and rigidly held at their upper ends; second, to

page_text: provide a method of winding the strings upon their stringers whereby the space
required between the stringers at this part need not exceed the thickness of one
string, while it admits of the strings being brought practically into one line or plane
between their fastenings and the upper bridge; third to prevent or limit the
outward or inward movement of the lower parts of the stringers by causing those
tending to move inward to oppose and balance those tending to move outward;
fourth, to prevent or limit the lateral or twisting motion of the stringers by causing
the inward or outward turned parts to pass between opposite or different parts of
adjoining stringers; fifth, to facilitate tuning where the tuning-nuts are equi-
distant by placing a distinguishing-mark upon the adjacent parts in suitable
position to indicate which string is operated by any particular nut. Sixth, to
provide a means of spacing the upper ends of the strings of a piano where no means
of spacing are provided at or upon the stringers, and at the same time to avoid
undue friction or resistance to the motion of the string which must accompany any
such means when fixed to the agraffe, bridge, or pressure-bar. These objects are
obtained by the methods and means described herein, and shown in the drawings
filed with the Provisional Specification, in which,
Figure 1 is a front view of the tuning device.
Figure 2 is a vertical section of the device as applied to the treble part of the
piano.
Figure 4 is a slightly different form of the stringers with sections shown at
three points.
Figures 10 and 11 show the guide-pieces used in the bass part between the
stringers.
Figure 20 shows a form of adjusting-nut having tapered squares upon its upper
part.
Figure 12 shows more openly the method of winding the strings upon their
stringers and their relation to each other.
Figure 3 shows the arrangement of the stringers in the bass part with the guide-
pieces between them and also the form of projecting flange in that part to suit the
inclined position of the stringers.
Figures 5 and 6 show a modified form of the means of limiting the inward or
outward movement of the lower parts of the stringers. Figures 7 and 8 show
another form of the same. Figures 5 and 8 show, also, modified forms of stringers.
Figure 13 shows my method of winding the strings in relation to each other by
a section taken through the string-fastenings along the dotted lines X of
Figure 2.
Figure 9 shows a modification of the plate H, having guide-grooves on each side
to receive and guide the returned or hooked ends of the stringers.
I will here explain that in this Specification and claims the word "spacer." or
"coupler" refers to an essential part of my improvement, which is marked in the
drawings as C, C¹, C³, C and C, and represents the means described and claimed
by which the strings are drawn together or regulated to the desired distance apart.
The word "stringers" refers to that part of a tuning device to which the string is
fastened. By the words "set of two strings" or "set of three strings" is meant a
set which together form one note and have the same pitch. By the terms "spacing
the strings" I mean the adjusting or maintaining of the strings at the desired distance
apart from each other, as shown in Figure 1. The term " upper ends of the strings
refers to the parts shown in the drawings and as located in an upright piano: and,
finally, the term "agraffe or
"bridge" refers only to the agraffe or bridge. near
the upper ends of the strings and is shown at E and does not include an agraffe
or bridge upon the sound-board, the function of which is to communicate the
vibrations of the strings to the sound-board.
"
"
The drawings show the figures as arranged in an upright piano, and the terms
used in this Specification and claims are intended in this sense-that is, as scen
in Figure 1.
In the drawings similar letters refer to similar parts.

page_text: In Figures 1 and 2, G represents the main plate of a piano, to which the
projecting flange G³ is cast or fixed. In this flange holes are drilled in two rows
and staggered, as shown in Figures 1 and 2, into which holes the stringers A and A¹
are fitted and made adjustable by the nuts a and a', Figure 1. These stringers are
identical in shape, but are reversed in position. The upper screw-threaded part is
I of round section, as is also the hooked or returned end, while the part between
them is of oval or elliptic section. The oval or elliptic form of this part has the
advantage of increased strength and of offering no sharp angles or flat faces to the
string-windings, so that they are not liable to break at this part and will wind snug
and uniform upon their stringers. The ends of the strings are passed through the
holes shown at O, Figure 4, and the strings are wound about their stringers, so
that the last coil will come into the required position, as shown in Figure 2, so that
when the stringers are arranged and adjusted in position the string-windings shall
come quite close to but not overlap each other.
It is desirable in arranging the stringers in their places to put a few only at
each end of the bar H, or the position where it will come, and after putting a
slight tension on these to place the bar in position. The stringers should then
be added alternately, so as to balance each other's pressure upon the bar H.
This bar may be in one or more pieces of any suitable length and curve, but
not too short: otherwise the motion of one stringer (in tuning) may cause it to
become displaced through the insufficient pressure of the others upon it. In
Figures 1, 2 and 3 the bar H is shown plain, but may, if preferred, have grooves,
as shown at Figure 9, to guide and steady the stringers. It will be seen that
the bar is not fastened to the plate G or to the flange G', but is held in position
by the ends of the stringers A and A¹, which press against it in opposite directions.
It may, however, be applied to the parts of the strings just below the stringers,
in the same manner as the plate is applied to the stringers in Figures 6 and 5,
but with the curves or corrugations of the plate Z in Figure 6 shallower, so
that the strings may be in one line or row, somewhat like the spacer C³,
Figure 14 or a plate may be placed upon each side of the string and attached
together by suitable means: but I prefer placing the guide plate or plates upon
the stringers.
In Figures 1, 2 and 3 the strings F and F¹ are attached to the stringers A and A¹,
respectively, the difference in F and F" being in position and direction of the string-
windings only. The oval part of the stringers is shown as lying central with the
other parts, but may, if preferred, be at one side. In Figure 4 is shown a notch or
indentation in the stringers at R to receive and regulate the positions of the last
coils of the strings: when very precise adjustment of the strings is desired.
In Figure 2 the stringers A are shown quite close to the plate G, and they may
be allowed to bear lightly against it: but this is not necessary, and they should not
in any case press hard upon it, as this would increase their resistance to motion
when tuning. As the stringers in the bass part do not come close enough together
to prevent twisting motion, I employ guide-pieces, (shown in position in Figure 3,
and separately in Figures 10 and 11), and in order that they may grip the bar H
firmly and still be capable of adjustment in relation to the stringers the width apart
of the straight parts should be less at the ends than elsewhere so that when placed
upon the bar they will clamp firmly upon the bar and prevent jarring or
displacement.
In the treble part of the piano the hooked or returned ends of the stringers
should just fill the space between adjoining stringers, as shown along the dotted
lines of Figure 1, to prevent lateral motion of the stringers. In Figure 12 it
will be seen that the string fastenings are in two rows and staggered and that they
all wind around the stringers in the same direction: but the coils are arranged
alternately inward and outward along them, so that the downwardly-proceeding
parts come, practically, in one line or row. This latter is also shown in Figure 13, §
where the small circles represent sections of the strings, and those that are
blackened or solid represent the downwardly-proceeding parts,

page_text: In the modifications shown in Figures 5 and 6 the plate Z is shown wound round
or laced between the stringers, and in Figures 7 and 8 the plates are placed on
either side of the stringers and held together by suitable means, such as the bolt
shown in Figures 7 and 8. These plates may also have guide-grooves, as at D,
Figure 7, to guide the stringers.
In Figure I three of my spacers C are shown clasping and drawing together the
two outer strings of each of the three sets of three strings. In this figure there is
also a series of spacers C¹ applied to the middle strings, connecting a middle string
with the middle string of an adjacent set.
Five different spacers are shown in the drawings at C, C¹, C³, C³, and C. The
spacers C¹ of the middle strings are shown in Figure 1 and are also shown in
suitable form in the drawings in Figure 17. They are attached in a similar manner
to spacers C, except that they overlap each other, the one middle string being held
by opposite ends of independent spacers.
The arrangement of the couplers or spacers upon the strings will greatly depend
upon the positions of the string-fastenings in relation to each other. If it is
desired to bring the two outer strings of adjoining sets closer to each other instead
of as shown, these two outer strings may be coupled together. If each adjoining
middle string inclines toward their stringers in opposite directions, each alternate
middle-string spacer may be dispensed with. In most cases where the string-
fastenings are equally distant the middle-string spacers will not be required.
The spacers may be made of any suitable material, preferably of piano-string
wire, as this is always available to a tuner, if one should get broken or lost. They
may also be of various forms, as shown, and they may be arranged side by side, as
shown, or in any other suitable position in relation to each other or to the stringers
or to the agraffe or bridge and may be either above or below the pressure-bar, if
one is used on the strings. It will be seen that the method of spacing shown is
practically without frictional resistance to the motion of the strings in tuning, and
consequently does not cause unequal tension of the two parts of the string above
and below the agraffe, or upper bridge.
It will be seen that the spacers may be so made and applied as to either push or
draw the strings in a sideward direction, see Figures 1 and 19, or in an inward or
an outward direction, see Figures 14 and 16.
I do not limit myself to the precise form of stringers or guide-plates or spacers
shown and described herein, as they may be variously modified.
The distinguishing features of my devices and methods are as follows :-
First. The usual method of limiting or preventing the inward or outward
movement of the lower parts of the stringers or upper parts of the strings and so
regulating them in relation to each other is to allow the stringers tending to move
inward to bear against the plate G or a plate attached thereto and to press the
others inward by means of a plate bearing against their outer faces or against the
strings just below them and screwing this plate to the plate G. My method is
distinct from this, in that the devices are capable of performing their office without
being attached to or in contact with any parts of the piano except the stringers or
strings, the parts tending to move inward opposing and balancing those tending to
move outward, by means of the plate H or its equivalent. This feature includes all
devices which do not require to be attached to other parts than the stringers or
strings in order to perform their functions-that is, to regulate the position of the
upper parts of the strings in relation to each other even though it may be con-
sidered desirable to attach them to other parts in order to regulate the strings or
stringers in relation to these other parts. They are not intended to regulate the
general inclination of the upper parts of the strings to their sounding parts or to
the plate G. This may readily be done by suitably placing the flange G³ or the
holes therein or the agraffe or bridge E, in relation to each other.
Second. In order to snit the usual construction of pianos the distance apart of
the stringers along the flange G (in tuning devices of this class) must be about
seventeen and a half one-hundredths of an inch, or. three and one-half inches for

page_text: -
twenty stringers. Now, if the strings are fastened as shown-that is, wound about
their stringers and the coils are opposite each other in one row or line, (which is
the usual method of bringing the upper parts of the strings into one line or row),
two thicknesses of string have to be allowed for between each pair of stringers, so
that the stringers have to be very thin at this part and the strings bent very sharp,
which weakens both stringer and string. 1 avoid these defects by placing the
string winding or coils in two rows, one behind the other and alternately arranged,
and by winding the coils alternately inward and outward and toward each other
along their stringers I bring the last coils close together, so that the strings proceed
downward to the agraffe in one line or row, or sufficiently so for practical purposes. 1
I am aware that the string-windings have before been arranged in two rows
alternately, one above the other, and having their strings proceeding downward in
one line or row: but I am not aware of any tuning devices in which the fastening-
coils are arranged in two rows one behind the other, alternately, or otherwise, and
capable of passing without displacing each other in their up-and-down-motion in
tuning and having their last coils close together, so that the strings proceed down-
ward in one line or row. My devices require less room vertically than the latter
form, so that longer strings, etc., may be used in pianos of the same size.
Third. I am aware that devices have before been used in which the stringers
(which are not alternately arranged or reversed in position) are steadied or guided
laterally by contact with adjoining stringers: but I am not aware of any tuning
device in which the stringers are arranged in reversed positions and are guided or
steadied laterally by a part of one stringer being in contact with other substantially
different parts of the stringers.
Fourth. To enable a tuner to readily see which nut is connected with the string
he wishes to tune, I place a mark upon the flange G¹ just in front of the tuning-
nuts or upon the plate G just above and behind them. By means of such marks
uniformly arranged (opposite to a corresponding nut in each set of three) it can
readily be seen which nut operates any particular string-viz., if in front of the
middle nut it indicates that this nut operates the middle string: if midway between
two sets of nuts, it indicates that the first nuts to the right and to the left are
those which operate the left-hand and right-hand outer strings, respectively, of
those sets.
Fifth. The strings are shown equally distant from each other as they leave the
stringers, whereas they are required to be grouped into sets of three where the
hammers strike them by means of some spacing device. This usually consists of
grooves or holes in the bridge E or the agraffe or the pressure-bar when used: but
this and all similar means are objectionable, because being fixed in relation to the
strings these grooves or holes offer considerable resistance to the motion of the
strings when the latter are being tuned, thereby producing unequal tension of the two
parts of the string above and below the grooves or holes, and as this unequal tension
tends to balance itself slowly after the strings are tuned, a change of tension results
in the sounding portion of the string, and consequently a change of pitch, putting
the string again out of tune.
My method of spacing the strings has the advantage of and is distinct from all
others of which I am aware, in that the spacers or couplers are free to move with
the strings and are independent of and not necessarily attached to any part of the
piano except the strings-that is to say, they (the spacers or couplers) are held in
place and supported by the strings only, and are not hindered by other parts of the
piano from following the motion of the strings to which they are attached when the
strings are being moved up or down in tuning, although of course they may
accidentally be in alight contact with other parts. In other words, the spacers or
couplers perform their office by forcing apart or drawing together two or more
strings, thus displacing the strings from their previous positions, bringing them into
the positions desired, and at the same time balancing the force produced by the
tendency of the strings to revert to their previous positions, without being fixed or
attached to any part of the piano except the strings.

page_text: The advantage of my method consists in the fact that only a slight resistance
(which is chiefly by rolling friction) is offered to the motion of the strings, so that
no material difference occurs from this cause in the two parts of the string above
and below the agraffe or bridge.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
1. In a piano stringing and tuning device, the combination, with the stringers
and strings, of one or more plates or pieces of metal or other suitable material
suitably arranged upon and held in position by the stringers or adjacent parts of
the strings and not necessarily in contact with other parts and adapted to regulate
the inward or outward position of the strings in relation to each other, the pressure.
of those parts tending to move inward opposing and balancing those parts tending
to move outward by means of said pieces or plates, substantially as described.
2. In a piano stringing and tuning device, the combination, with the stringers
and strings, of pieces or strips of metal or other suitable material adapted and
applied to the lower parts of the stringers or adjacent parts of the strings and
capable of limiting or regulating the inward or outward inclination of the upper
parts of the strings in relation to each other without being attached to any parts of
the piano except the stringers or strings, substantially as described.
3. In a piano stringing and tuning device, the combination, with the stringers
and strings, of the string fastenings or coils arranged upon their stringers in two
rows, one behind the other, and having the windings or coils of each row directed
toward the windings or coils of the other row, so that the downwardly-proceeding
parts of the stringers may be brought very nearly into one line or row or inclination
toward the agraffe, substantially as described.
4. In a piano stringing and tuning device, the hook-shaped stringers arranged
in alternately-reversed positions and having their lower parts guided and their
lateral motion limited or prevented by being in contact with a substantially different.
part of adjoining stringers, substantially as described.
5. In a piano, the combination, with the tuning devices, of suitable marks.
arranged in uniform positions near each set of three tuning-nuts, whereby corre-
sponding nuts of each set may be distinguished from others, substantially as
described.
6.-In a piano stringing and tuning device, the hook-shaped stringers arranged
alternately in reversed positions and provided with suitable means of attachment to
the piano at their upper parts and to the strings at their lower parts, substantially
as described.
7.-In a piano stringing and tuning device, the combination, with the stringers,
of a bar or plate placed between the two rows of stringers, substantially as
described.
8. In a piano stringing and tuning device, the stringers A or A', having a
screw-threaded upper part, in combination with a string-receiving part of oval or
elliptic section and a hooked or upwardly-returned lower end, substantially as
described.
9. In a piano stringing and tuning device, the combination of the stringers A³,
having their lower ends hooked or returned upward and inward and passing between
the upright portion of the stringers A, with the stringers A having their lower ends
hooked, returned upward and outward, and passing between the upright portion of
the stringers A', substantially as described.
10. In a piano stringing and tuning device, the stringers having their lower
ends hooked or returned upward and passing between the upright portion of
alternate stringers, substantially as described.
11. In a piano stringing and tuning device, the combination of the stringers A
and A' with the bar H, the hooked or returned ends of the stringers A pressing
against the inner face of the bar in an outward direction and the hooked or returned

page_text: ends of the stringers A' pressing against the outer face of the bar in an inward
direction, substantially as shown and described.
12. In a piano stringing and tuning device, the combination, with the stringers
and the bar, of the guide-pieces L and M, placed between the stringers and on the
bar, substantially as shown and described."
13.-The method of spacing the upper ends of the strings of a piano by means
of couplers or spacers placed upon the strings between the agraffe or bridge and
the tuning devices adapted to and moving with the strings, being independent of
any other parts of the piano and connecting two or more of said strings with.
each other.
14.-The method of spacing the upper ends of the strings of a piano by means of
spacers or couplers placed upon the strings between the agraffe or bridge and the
tuning devices, capable of following the motion of the strings and being independent
of other parts of the piano, and adapted to clasp and couple any one string with any
one of those adjacent to it.
15.-The method of spacing the upper ends of the strings of a piano by means
of spacers or couplers placed upon the strings between the agraffe or bridge and
the tuning devices, capable of moving with said strings and disconnected from other
parts of the piano, and adapted to clasp or hold two or more neighboring strings at
fixed distances from each other.
16. The method of spacing the upper ends of the strings of a piano by means of
spacers or couplers placed upon the strings between the agraffe or bridge and the
tuning devices, being free to move with the strings and disconnected from all other
parts of the piano, and adapted to clasp and draw two neighboring strings toward
each other.
17. The method of spacing the upper ends of the strings of a piano by means of
spacers or couplers placed upon the strings between the agraffe or bridge and the
tuning devices, being free to move with the strings and not necessarily attached to
any other parts of the piano, and adapted to clasp and connect any one string of a
set of three or a set of two with any one string of an adjacent set, drawing them
toward each other and holding them at fixed distances apart.
18. A spacer.or coupler applied to the upper ends of the strings of a piano
between the agraffe or bridge and the tuning devices and not necessarily fixed or
attached to any parts of the piano except the strings, and capable of spacing two
or more strings to a suitable distance apart by separating the strings from or
drawing them toward each other.
19. In a piano, the combination, with two outer strings of a set of three, of the
spacers C, placed upon the strings between the agraffe or bridge and the tuning
devices for the purpose of spacing said two outer strings to a suitable distance
apart, substantially as shown and described.
20. In a piano, the combination, with two middle strings, of the spacers C³,
placed upon the strings between the agraffe or bridge and the tuning devices for
the purpose of spacing the two said middle strings to a suitable distance apart,
substantially as shown and described.
21. The combination, with the strings of a piano, of the spacers C and C¹,
placed upon the strings between the agraffe or bridge and the tuning devices for
the purpose of spacing the said strings to a suitable distance apart, substantially as
shown and described.