Metallic Frames for Upright Pianos. FOR UPRIGHT PIANOS
Year: 1888

page_text: Metallic Frames for Upright Pianos.
I, NEWNHAM BROWNE, of 73 Cheapside, in the City of London, Fellow of the
Institute of Patent Agents, do hereby declare the nature of the said invention for
"METALLIC FRAMES FOR UPRIGHT PIANOS" which invention has been communicated
to me from abroad by Charles Bunce and Edwin H. Benedict, both of No. 56, Court
Street, in the City of Brooklyn, County of Kings, and State of New York, United
States of America, Piano Manufacturers, to be as follows:-
This invention relates to the frames of upright pianos in which the frame is
composed of a single metal casting, the casting including longitudinal bars extending
in the direction of the strings and proportioned in length to the length of the strings ;
a marginal plate supporting the hitch pins which are integral therewith; an inwardly
projecting continuous flange to which the sounding board is secured; the hammer
bridge over which the strings pass; a down-bearing bar supported by the bridge
through intermediate brackets, and an overhanging flange which retains in position
the wrest plank.. In connection with this metallic frame the invention comprises the
method or means for securing the sounding board, and the wrest plank thereto. The
invention is illustrated in the accompanying drawings in which
Fig. 1 is a plan view of the metallic frame. Fig. 2, is a bottom view thereof, the
wrest plank and sounding board being in position. Fig. 3, is a section in a plane
indicated by the line 3-3 in Fig. 2. Fig. 4, is a section in a plane indicated by the
line 4-4 in Figs. 1 & 2. Fig. 5, is a fragmentary view showing the method of
stringing at the hitch pins and sounding board bridge.
A, A, are the longitudinal bars which are bevelled, being wider on their outer than
on their inner sides; B, is the marginal plate on which are formed the hitch pins a, a ;
C, is the continuous flange which supports the sounding board; D, is the hammer
bridge; E, is the downbearing bar secured to the bridge by intermediate brackets F, F,
located at proper intervals; and G, is a top plate having an overhanging flange H;
all of which parts are cast or otherwise constructed in a single piece of metal.
I, is the sounding board which rests upon the flange C, cement indicated at b,
being interposed between the board and flange. The sounding board is secured in

page_text: place by screws e, passing through apertures d, d, cast in the flange C, which extend
through the sounding board and enter hard wood strips e, e, arranged along and glued
to the outer margin of the sounding board. The sounding board is held by the
flange C, away from and out of contact with the bars A, so that it is free to vibrate
throughout its entire extent. The wooden strips e, e, adjoining the marginal plate B,
where the hitch pins are located extend outward farther than the marginal plate, so
that when the strings are in position they bear down upon said strips, and so hold the
sounding board permanently and tightly against the flange C, thereby preventing any
jarring or looseness of the sounding board.
Between the bridge D, and the top plate G, is a space above the bars A, which is
wider at the treble than at the bass end of the frame, and which gradually diminishes
from the treble to the bass. Across this space the brackets F, carrying the down-
bearing bar, E, and the overhanging flange H, partly extend. The depth of the
bars A, beneath this space (that is between bridge D, and plate G, is preferably less
than beneath the sounding board, since this portion of the bars is relieved almost
entirely from the strain of the strings, and more space is thus left for the wrest
plank I. The wrest plank 11, which varies in width corresponding to the space
between the bridge and top plate, is inserted into said space at the treble end of the
frame, and is held between the bars A, at the back, and the brackets F, and flange H,
at the front. The wrest plank is held in place by being glued on its back to blocks J, J,
fitted in between the bars A, and accurately planed on both sides, and to the back of
these blocks is glued a back piece K, extending across the frame immediately behind
the bars. The wrest pin plank is prevented from tilting forward under the strain of
the strings by the overhanging flange H, and by the blocks J, which are held
from moving forward by the beveled sides of the bars A, and it is held from any lateral
movement by resting against the hammer bridge D, throughout its length.
In stringing the piano the strings are passed around the hitch pins a, a, thence over
and in contact with the hard wood strips, thence between pins f, f, on the sound board
bridge 9, thence over the hammer bridge D, thence under the downbearing bar E, to
the wrest pins h, h, on the wrest plank. The bridge D, and bar E, are formed with
suitable bearing edges for the strings, their edges being in different planes, that of
the bar E, being nearer the outer surface of the wrest plank than that of the bridge.
Being thus held there is no rattling of the strings, and they are kept firm and solid.
The diameters of the several hitch pins a, a, are just equal to the required spaces
between the strings, so that all of the strings are parallel with each other throughout
their lengths. The strings are also arranged in the line of the bars A, from the hitch
pins a, to the pins f, on the sounding board bridge, and from the latter to the hammer
bridge. The strings are thus kept at the proper proportional pitch during all changes
of temperature, since the length of the bars A, is proportioned to the length of the
strings, so that the expansion and contraction of the bars acts proportionately on the
strings to keep them all at the proper proportional pitch.
Since the bars are longer at the bass than at the treble end, it is important that the
wrest plank should be inserted at the treble end, where the plank is widest, in order to
economize space as much as possible.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. A metallic frame for pianos comprising in a single piece longitudinal parallel
bars proportioned in length to the length of the strings and in line with the strings, a
marginal plate, hitch pins on said marginal plate, a continuous flange for the support
of the sounding board, a hammer bridge, a top plate, above the hammer bridge having
an overhanging flange for the retention of the wrest plank, said top plate being formed
with said parallel bars which extend above the hammer bridge, and a downbearing
bar located above the hammer bridge between it and said top plate, said downbearing
bar being connected to the bridge by intermediate brackets substantially as set forth.

page_text: 2. The metallic frame having a supporting flange for the sounding board, in
combination with the sounding board resting on said flange, wooden strips on the outer
surface of the sounding board, and attaching screws extending through said flange
and board and into said strips, substantially as set forth.
3. The metallic frame having marginal plate or ring, the hitch pins thereon, and a
supporting flange for the sounding board, in combination with the sounding board
resting on said flange, and strips on said sounding board which project outward beyond
said marginal plate, whereby the strings press upon said strips and hold said sounding
board in place, substantially as set forth.
4. The metallic frame having in one piece longitudinal bars, hammer bridge, and
top plate having an overhanging flange, said top plate being connected to said hammer
bridge by said bars, whereby a space is formed between said top plate and bridge and
in front of said bars which is wide at one end and gradually narrows to the other end,
over which space said flange projects, in combination with the wrest plank which is
inserted into said space, and which rests in front of said bars against said,hammer bridge
throughout its entire length, and which is held beneath said overhanging flange,
substantially as set forth.
5. The metallic frame having hammer bridge, top plate having overhanging flange,
and connecting bars, in combination with the wrest plank, between said hammer
bridge and top plate, and resting on said bars beneath said overhanging flange, blocks
inserted between said bars and glued to the wrest plank, and a back piece behind the
bars glued to said blocks, substantially as set forth.
6. A metallic frame for a piano comprising longitudinal bars proportioned in
length to the length of the strings, a hammer bridge, and a top plate above the
hammer bridge connected therewith by the longitudinal bars, so that a space is left
between them for the reception of the wrest plank said space being widest at the
treble end of the frame, and gradually narrowing to the bass end, substantially as
set forth.