Improvements in the Frames of Pianofortes and similar Instruments.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Frames of Pianofortes and similar Instruments.
I, WILLIAM WORBY BEAUMONT of The Outer Temple, 222 Strand, London,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to the construction of the frames of pianofortes and similar
musical instruments. With the object of lightening the frames of these instru-
ments as heretofore constructed, and of obtaining the necessary strength rigidity
and tone, and to avoid the effects of large coefficient of expansion of aluminium,
I construct them of aluminium or aluminium alloy and of other metals having a
different coefficient of expansion or contraction, so that the difference between
the said coefficient of aluminium or aluminium alloy and of the steel or other
material of the wires of these instruments may be neutralised or not brought into
effect, or I form the frames so that the elastic resistance of the compression
members or parts of these frames, may conform to the expansion or contraction
of the wires of the instrument. For this purpose I prefer to construct the main
parts of the frame of aluminium alloy, and the struts, bars, or main compression
imembers of iron or steel or other metal of lesser coefficient. These compression
members may be solid of suitable sections or of circular or other tubular section,
and may be connected to the main parts of the frame by socket or spigot connec-
tions screwed or shrunk in or on the corresponding parts, or may be connected
by flanges or by otherwise formed ends of such struts or bars connected by bolts
or rivets, or by suitable fittings or housing, or the struts or bars may be cast into
or on the aluminium or alloy castings of such frames, by inserting them in the
frame moulds, and the virtual length of such struts may where necessary be
increased by placing one or more steel or other tubes within another or others,
so that the accumulated expansion or contraction of their combined lengths may
be utilised, or bars or plates suitably connected may be similarly employed for
building up or connecting parts of the frame and avoiding high expansion effects.
Dated this 24th day of December 1896.
Improvements in the Frames of Pianofortes and similar Instruments.
I, WILLIAM WORDY BEAUMONT of The Outer Temple, 222 Strand, London,
Civil 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 the construction of the frames of pianofortes and similar
musical instruments. With the object of lightening the frames of these instru-
ments: as heretofore constructed and of obtaining the necessary strength rigidity,

page_text: and tone and to avoid the effects of large coefficient of expansion of aluminium I
construct them of aluminium or aluminium alloy and of other metals having a
different coefficient of expansion or contraction so that the difference, between
the said coefficient of aluminium or aluminium alloy and of the steel or other
material of the wires of these instruments may be neutralised or not brought into
effect or I form the frames so that the elastic resistance of the compression
members or parts of these frames may conform to the expansion or contraction of
the wires of the instrument. For this purpose I prefer to construct, the main
parts of the frame of aluminium alloy and the struts bars or main
members of .iron or steel or other metal of lesser coefficient. These compression
compression
members may be solid of suitable sections or of circular or other tubular section
and may be connected to the main parts of the frame by socket or spigot.connec-
tions screwed or shrunk in or on the corresponding parts or may be connected by
flanges or by otherwise formed ends of such struts or bars connected by bolts or
rivets or by suitable fittings or housing or the struts or bars may be cast into or
on the aluminium or alloy or other castings of such frames by inserting them
in the frame moulds. The frames made according to my invention are intended
to be capable of withstanding all the stresses brought to bear upon them, by the
combined tensions of all the wires without requiring any support or aid from the
wood casing or framework of the pianoforte or other, instrument and the frame
may be placed in a case as is usual or it may. rest or be attached to a table or under
frame so that it is exposed or open to view except when under a suitable cover
instead of being boxed in.
My invention applies to the frames of upright, as well as horizontal pianofortes.
In the drawings hereunto attached
Fig. 1 is a plan of a frame suitable for a short grand pianoforte.
Fig. 2 is section through parts of the two main portions of the frame and
through the strut or post at the bass side..
Fig. 3 is an end view of the frame from the key board end.
Fig. 4 is, a section on the lines and zz of Fig. 1 'the dotted lines showing the
section zz,
Fig. 5 is a section of the treble end of the frame showing the connection between
the two main parts.
Fig. 6 is a side or.edge view of the treble end of a frame.
Figs. 7, 8, 9, 15, 10, and 17 are modifications of the modes of making the
connection between the main parts.
Fig. 10 is a plan of a frame in which the bass side posts is at right angles with
the metal wrest plank and key board and in which the part carrying the hitch-
pins for the fixed ends of the wires is of different form to that shown in Fig. 1.;
Figs. 11 and 12 are cross sections of the long post and show methods of "
connecting the belly to it for frames n'ot enclosed in cases in the usual way.
Figs. 13 and 14 are sections of part of the wrest plank of the frame and of the
long post and of the connection between the hitch pin-plate and wrest plank at
the treble end the post and connecting piece not being tubular.
The "wrest plank" A of the frame of the grand pianoforte may be of the typo
shown but may vary according to practical requirements and as to the tuning pins
and length of wires and it may be made of aluminium alloy of from about
0.3 specific gravity upwards or of iron or steel. The ends are preferably made with
sockets as shown the sockets being in some cases bored to fit the long post Band
the end of the short post or connecting piece C. These posts are preferably of
circular steel tubes the long, post being preferably taper as shown and the ends
may be parallel or taper where they fit into the sockets at the ends of the metal
wrest plank A and plate D. The short post C may be similarly formed at its
ends. The ends of the posts may bed into the bottom of the sockets as shown
in Figs. 2 and 5 or one or both ends may be free as in Figs. 15, 16, 17, the posts
resting in the sockets by internal shoulders as at c Fig. 15 or by a shoulder or
collar as at c Fig. 10 which may be formed by: an enlargement of the tubular

page_text: post as at c Fig: 17 on which a steel ring d or ring of other suitable inėtal may
be fixed or shrunk to provide, a flat bed for the socket of the frame. Preferably
the arrangement shown in Figs. 2 and 5 is used for the wrest plank end of the
posts when the plank is of iron or steel and the arrangement shown at. Fig. 15
may be used both for the wrest plank and for the hitch-pin plate D when of
aluminium alloy more especially when the frame is for cross string pianofortes
as in the examples shown as this compensates more fully for differential expansion
and contraction: When the cross string arrangement is not used the form shown
by Fig. 16 may be used. In all these cases the bolts e are used passing through
the two main parts of the frame and the posts. These bolts may however be
dispensed with when the posts are made a tight accurate fit in the
sockets or when the posts are cast into the sockets, by methods well
known to founders. When the latter process is adopted the part, of the
post which is nearest the collar in either case may before putting it into
e mould before casting be heated and be brushed over with black lead and..oil
or other suitable thin coating when aluminium is used so as to prevent metallic
union or adhesion except at the extreme half or thereabout of the socket euds of
the post and thus. to allow more perfectly for expansion differences in the two
different metals.
'3
The sockets. may be formed as shown at Figs. 8 and 9 where the socket is split.
for part of its length on one side and a clamping bolt b used which tightens the
socket on the post end. Another modification of the connection of the main
parts and posts is shown at Fig. 7 where the post fits into the bottom of the socket
but is free along its length except at the month of; the socket where a ring-f
slightly taper and split at one place is driven or screwed in the ring f being
made preferably of a metal having a coefficient of expansion about the mean of
that of the metals of the post and of the sockets.
Modifications of the sections of the posts and of the means of fixing them to
the parts A and I are shown in Figs. 13 and 14 the posts being of split tube or
channel form fixed in place by keys g between lugs-h and a central piece cast
with A and D.
A suitable transverse section of the metal wrest plank or plate A is shown
upon it the central stiffening rib a being placed in a position not interfering with
the requirements of the screw studs tuning pins and other parts. The section of
the wrest plank may however be varied to suit, different sizes and forms. including
those for the upright pianofortes.
The preferable section for the hitch-pin plate D of Fig. 1 is shown at two places
by Fig. 4 an essential part of these sections being the combination with the thick
tension edge of the plate of the vertical stiffening ribas near as possible
to the hitch-pin lines so that it formis effective material as part of a tension
member kl.and with the back, part of the plate extending to the compression
member m, the rib being of variable depth greatest near. Beneath the
curved hollow part of D are cast ribs E Figs. 4 and 4 and shown as to position.
by dotted lines in Fig. 1 situated so as to act as struts and ties in the plate Das
a girder as well as stiffeners. As far as possible the projecting parts of the
ornament upon the plate D some of which is indicated on Fig. 1 are made to
follow the lines of the ribs E so that their material adds to the stiffness of the
plate. The section on Z-Z of Fig. 1 shown by Fig. 4 shows approximately the
form across the raised part and bridge hole for the bass strings: As shown by
Figs. 1, 2, 3, 4, 5, 6 and 10 the frame has an underside flat or formed suitably for
placing in a case in the ordinary way. When the frame is made to stand free
from a case the section at a Fig. I would be preferably, as in Fig. 4 where the
compression member m of the plate D is extended downward covering the edge of
the sound board or belly n which may be fixed to this part of the frame by screws
or bolts through bosses at suitable intervals as shown. Along the end of the
belly next the hammers support may be obtained from an angle iron or steel bar
as shown in dotted lines at p Figs. 2 and 6 or bar of other suitable section. The

page_text: fixing of the belly to the long post B may be effected as shown by Fig. 11 or Fig. 12
by means of screws and the intervening piece which in Fig. 11 is a strip of
hard wood or pieces of hard wood of short lengths and which in
Fig. 12 is a piece of channel iron of the whole length of the post
or in short lengths in either case preferably brazed to the post B:
Other means may be used such as clip rings embracing the post at
intervals and having screws which pass through the belly. When not in a case
the frame may be supposed mounted on brackets or supports above a table as
shown in dotted lines in Fig. 2 for the outer or hitch-pin end and as in Fig. 6
for the action end the part being extended backward to carry the key board and
other parts of the action.
In some cases the post B may bed into the socket in the plate D at the end as
shown in Figs. 2, 5 and 7, and also by an intermediate shoulder as in Fig. 15
the plate being divided at the interior shoulder as indicated by dotted lines at t..
Fig. 10 so that the part above the intermediate shoulder may expand from it
and the part below t expand from the outside shoulder. The part between
would in this case be increased in section.
10
By Figs. 1, 4 and 10 I have shown frames with a slot for a bass bridge for over
or cross string pianofortes. My invention is equally applicable to ordinary
frames without cross strings and the methods of connecting the parts of the
frames as described are also applicable to frames not made in any part of
aluminium.
Although I have only shown tubular or split tube and channel shaped posts
as preferable forms I do not restrict myself to these sections but may use bar or
other forms of posts rigidly fixed by the whole or a greater or lesser part of their
length of contact with the wrest plank and hitch-pin plate. And although I
have shown only barless frames i.e. frames without any struts or bars over the
wires or strings I may in some cases use one or two such bars preferably of steel.
Having now described and ascertained the nature of my said invention and in
what manner the same is to be performed I declare that I am aware that piano-
forte frames have been built up in various ways afd that it has been proposed to
make aluminium frames and I do not claim built up frames or aluminium frames
generally but what I do claim is
1. The combination of aluminium or aluminium alloy wrest plank & hitch-pin
plates with iron or steel connecting posts substantially as & for the purposes
herein described.
2. The combination of aluminium alloy hitch pin plate with steel or iron posts
& steel or iron wrest plank substantially as & for the purposes herein described &
shewn.
3. In frames for pianoforte and similar instruments the methods of connecting
& forms of connection of the wrest plank A hitch pin plate D & posts and D
substantially as & for the purposes herein described.
.
4. In frames for pianoforte & similar instruments the combination of aluminium
parts with steel or iron parts with posts or connecting pieces so connected that
differential contraction & expansion' as between the wires & the aluminium parts
are approximately neutralised substantially as herein described & shewn.
6. In frames for pianofortes & similar instruments a hitch-pin plate having a
section in which a stiffening rib forms part of tension member substantially as
herein described and shewn.
D
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