Improvements in the Construction of Pianos.
Year: 1890

page_text: Date of Application, 2nd May, 1890-Accepted, 12th July, 1890
COMPLETE SPECIFICATION.
Improvements in the Construction of Pianos.
We, ARTHUR W. DAVIDSON, Piano maker of 3131 Dakota Street, and CHARLES
SIGMUND, Piano polisher of 1305 Moore Street, both of Philadelphia in the County
of Philadelphia, State of Pennsylvania, United States of America, do hereby declare
the nature of our invention for "IMPROVEMENTS IN THE CONSTRUCTION OF PIANOS,"
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
Our invention relates to an improvement in the construction of pianos, especially
to those of the upright type, and has for its object to provide a means whereby
the pin block will be securely attached to the back timbers or bracings of the
instrument, and also to utilize the attaching mediums as conductors and transmitters
of sound.
The invention consists in the combination with the pin block and its support, of
tubular or trumpet-shaped bolts and in the novel construction and combination of
the several parts, as will be hereinafter more fully set forth and pointed out in the
claims.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which similar letters and figures of reference indicate corresponding
parts in both the views.
Figure 1 is a partial vertical section through an upright piano;
Figure 2 is a front elevation of the pin block and a portion of the metal frame
connected therewith.
Figure 3 is a view similar to that shown in Figure 1, showing a modified form
of device.
Figure 4 is a front elevation of form shown in Figure 3.
In carrying out the invention I do not alter the form of the casing 10, nor the
bracings or back timbers or standards 11, and the sounding board 12 and the
metal frame 13 remain the same, the latter being provided with the usual guide
ribs 14 and stationary pins 15. The wires or strings 16 are also strung as hereto-
fore, our improvements relating especially to the novel means for connecting the pin
block 17 to the bracings or back timbers 11.
The means above referred to consist of tubular bolts 19, either straight, conical
or trumpet-shaped, preferably the latter, which bolts are usually made in two
sections a, and a', as illustrated in Figure 1. The section a, which comprises the
body, is of sufficient length to extend through and beyond the pin block 17 and
the bracings or back timbers 11, and is provided with an exterior thread at each
extremity. The body sections are so located that the larger ends will face the front
of the casing of the instrument.
The section a', which is the bell section, is interiorly threaded at its reduced
end, and screwed upon the front extremity of the body section to a bearing against
the front face of the pin block, as indicated in Figure 1, and upon the inner or rear
face of the body section a, of the tubular bolts, a nut 20 is screwed, having a bearing
against the rear face of the bracings or back timbers 11. Thus, as the trumpet
section a' acts as a nut, and a nut is placed upon the rear or inner end of the body
section a, the two parts above nained may be so manipulated as to firmly and
effectually bind the pin block 17 to the bracings or back timbers or supports 11. It
is also obvious that a bolt, or bolts, of the description above described, tends to
strengthen the pin block, which, if desirable is also glued in the ordinary manner to
the bracings or back timbers. If in practice it is found desirable, the bell sections a¹
of the bolts 19 may be made to extend a short distance out beyond the front face of
the pin block 17, but preferably the said section is made to extend to the front of the
case, as shown.

page_text: In addition to the tubular bolts 19, we form at the upper rear portion of the
instrument, to the rear of the bracings or back timbers 11, a compartment 2.1, by
providing a back board at the rear of the instrument.
The bolts above described not only serve to effectually prevent the pin block from
being detached from its support by the continual tension upon the wires or strings, but
the said bolts also serve as conductors or transmitters of sound, increasing the volume
of sound, especially so when the chamber 21, is located at their rear, in which event
a series of passages are provided, serving to convey the tone from the back of the
instrument to its front.
In Figures 3 and 4 is shown a modified form in which the back timbers 11 are cut
away and a tube or pipe 22 is brought from the centre of the sounding-board between
braces to the opening in the back timbors. In this case there is no chamber 21, and
a hollow bolt 19 is inserted through the pin block below the agraffu 24 so as to open
into the cut-away portion of the new bracing, thus making a double series of escapes
for the sound. The tubular bolts may be either round or square, as desired.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what wo
claim is :-
1. The combination in a piano with the pin block, a parallel support to which the
rear or inner face of the said block is secured and the sounding board, of transverse
tubes connecting said block and support and also connecting the space at the rear of
the sounding board with the front of the instrument, substantially as set forth.
2. In a piano, or similar instrument, the combination, with the pin block, its
supports and a chamber at the rear of said supports, of tubular or trumpet-shaped
bolts passing through the said pin block and supports, and connecting the rear
chamber with the front of the instrument, substantially as shown and described.
3. In a piano, or similar instrument, the combination, with the pin block and its
supports, of tubular, essentially trumpet-shaped bolts, each comprising a body section
passing through the pin block and a support therefor, a trumpet section screwed upon
the forward end of the body section, and a nut screwed upon the rear end of said
section, substantially as and for the purpose specified.
4. In a piano, or similar instrument, the combination, with the pin block and its
supports, of tubular or trumpet-shaped bolts passing through said pin block above and
below the agraffe and connected to said supports, a portion of said supports being cut
away, and tubes connecting the centre of the sounding board and said cut-away
portion of the supports.
ARTHUR W. DAVIDSON
CHARLES SIGMUND.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicants.