Improvements in and relating to Piano-key Levelling-pins fór Balance Rails.
Year: 1889

page_text: Date of Application, 8th Jan., 1889
Specification Accepted, 23rd Feb., 1889
Improvements in and relating to Piano-key Levelling-pins fór
Balance Rails.
I, WALTER ADELBERT CHURON, residing at Clifford, in the County of Oswego and
State of New York, one of the United States of America, Piano Maker and Tuner,
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 balance-rail pins for levelling the keys of piano-fortes,
organs &c.; and the object of my improvement is to provide a pin of simple con-
struction capable of permitting each key in said instrument to be raised or lowered
or inclined to the right or left independently of the adjacent keys so that a whole row
can be levelled promptly without requiring the removal of any key; and permitting
each rail-pin to be bent to the right or left, forward or backward.
Referring to the accompanying Drawings:
Figure 1, is a side view of the pin constructed in accordance with my invention.
Figure 2, is a vertical section of the same with one of the keys of a piano and a
portion of the cross-rail thereof shown by dotted lines in cross-section.
Figure 3, is a vertical section of a portion of the pin on a larger scale showing
one or two threads removed from the lower end of the screw to facilitate the bending
thereof at that point when the screw is made of Bessemer steel or other similar rigid
metal.
⋅
Figure 4, is a vertical section of the socket or handle for driving the bottom piece
of the pin in the cross-rail of a musical instrument.
Figures 5, 6 and 7, are modifications.
The pin is made in two pieces. The lower piece, A, consists of a suitably-sized

page_text: wire or polygonal small rod, preferably square, cut in short lengths (of about one
inch and a quarter) one end of which is pointed at, a, to facilitate its insertion into
the cross-rail (also called the balance rail) of the musical instrument, and the opposite
end of which is screw-threaded at, a³, to be inserted and retained in the piece, B
The body of the piece, A, being of polygonal form it is thereby prevented from
turning or becoming loose after being driven into the cross-rail, E.
The piece, B, consists of a tubular stem, made either of spun-metal or of a rod
bored a portion of its length and screw-tapped as shown at, b, to receive the screw-
threaded portion, a³, of the piece, A.
collar, 2, to form a rest for the lower edge of the piano-key, C, and the upper end
The lower portion of the piece, B, has a
has suitable means for engagement with a tool to rotate it. These means may be a
slot to receive the end of a screw-driver or a polygonal socket, or a polygonal stem
as, 63. To facilitate the production of a short bend upon the lower end of the
screw, a³, close to the point where it joins the body, A, particularly when the upper
end of said body is driven slightly under the top of the balance-rail or said balance-
rail is grooved or recessed, the underside of the collar, 63, of the piece, B, is made
convex or semi-spherical at, 6, so that the edge of said collar will not impinge upon
said balance-rail, and when rigid metal, as Bessemer steel, is used for the screw, one
or two threads are removed from the lower or inner end of said screw.
As the screw, a³, must fit with considerable friction within the screw-tapped socket
of the piece, B, to prevent said piece from rotating under the vibrations of the
piano-key I found that a long bend (in contra distinction of a short bend) upon the
screw will cause it to become jammed and immovable in the socket of the piece, B, and
therefore found the present construction to be necessary.
The convexity of the underside of the collar, 62, also facilitates the swedging with
a hammer of the edge of the screw-threaded perforation therein to cause it to grasp
firmly the screw, a³, as above stated, and to produce friction of the upper end of the
screw against the interior of the piece, B, said, upper end is split longitudinally at, a*,
and the two halves slightly wedged or sprung farther apart.
The parts, A, and, B, are preferably inade of substantially non-corrosive metal, for
example, the part, A, of bronze and the part, B, of brass or of Bessemer steel.
To drive the part, A, in the cross-rail, E, of a piano, I prefer to use a socketed
metal handle, D, the socket, d, of which is of suitable diameter to loosely receive the
screw-threaded end of the part, A, and of suitable depth to receive the length
of the threaded portion intended to project above the said cross-rail, so that the
end, d, of the handle acts as a stop and gage in its use.
driven into the rail, the handle, D, is removed and the part, B, screwed upon the
After the part, A, has been
part, A, until its collar, 62, is close to the rail, and the operation is repeated for each
pin in the instrument. A piano-key is then made to straddle each pin so that it rests
upon the collar, 62, the top of which is preferably slightly convex to facilitate the
rocking of the key thereon, and if the slots in said keys have been properly bored,
the whole series of keys can be promptly leveled; but if any of said slots are not
vertical, or, if any of the keys are warped, they can be properly leveled by slightly
bending laterally the screw, a³, at the point where it issues from the cross-rail, and
said bending will not interfere with the vertical adjustability of the part, B, upon the
part, A, of the pin.
In the modification shown in Figure 5, the piano-key supporting collar, b², is in the
form of convex nut and is made independently of the piece, B, and said piece acts."
also as a jam-nut to retain said supporting collar or nut,-6, at the proper height.
In Figure 6; the screw, a³, of the part, A, extends clear through the internally 5
screw-threaded piece, B, and a jam-nut, a, is placed on the upper end of the screw
to lock the piece, B, after it has been set at the proper height.
In Figure 7, the part, A, is not screw-threaded but extends within the piece, B, :
nearly to the top thereof. The piece, B, has a collar, 62, at the lower end to support the
piano-key and its upper end is bored and screw-tapped to receive the screw, aº, 5
the lower end of which rests, upon the top of the part,.A...

page_text: 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-
A piano-key pivot-pin consisting of two parts, A, and, B, longitudinally adjust-
able upon cach other, the part, A, being adapted to be driven and retained"
immovable in a piano cross-rail, and the part, B, being provided with a stem at
one end and a flange having a convex under surface, 6, at the other, substantially
as and for the purpose described.