IMPROVEMENTS IN IRON-WRESTS FOR PIANOS
Year: 1884

page_text: 'We KARL OTTO and THEODOR WEIDENSLAUFER both in Berlin, Prussia, German
Empire do hereby declare the nature of our Invention for "IMPROVEMENTS IN
IRON-WRESTS FOR PIANOS" to be as follows:-
,
The object of our invention is to construct iron wrest frames for piano fortes, in
an improved manner, whereby increased lightness and compactness' are insured,
combined with an ample amount of strength and rigidity.
In carrying out our invention, we form the side portions of the frame of an
L section, and the intermediate thrust bars of a T section; the connecting portions
at each end being so formed that the Land T forms gradually merge into rec-
tangular forms. Suitable provisions are made in the webs of the iron struts for the
insertion of screws to secure the string board thereto.
Our invention affords great facility in construction, as the frame forming the
wrest may be cast to the exact form required, and the calculated strength may be
supplied in making the pattern for the casting whereby all undue weight is
avoided.
The construction herein described also enables pianofortes so provided to sustain
great changes of temperature and climate, as wood is entirely eliminated from those
parts which have to sustain the tension of the strings.

page_text: COMPLETE SPECIFICATION.
We KARL OTTO and THEODOR WEIDENSLAUFER both of Berlin, Prussia, German
Empire, do hereby, declare, the nature of our said Invention for "IMPROVEMENTS
IN IRON WREST FOR PIANOS," and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
The object of our invention is to construct iron wrest frames for pianofortes, in
an improved manner, whereby increased lightness and compactness are insured,
combined with an ample amount of strength and rigidity.
L2
In carrying out our invention, we form the two side portions of the frame of an
L section, and the-intermediate thrust bars of a T section; the connecting portions
at each end being so formed that the Land T forms gradually merge into
into rec-
tangular forms. Suitable provisions are made, in the webs of the iron struts, for
the insertion of screws to secure the string board thereto..
Our invention: affords great facility in construction, as the frame forming the
wrest may be cast to the exact form required, and the calculated strength may be
supplied in making the pattern for the casting; whereby all unduet weight is
avoided.
-
:
The construction herein described also enables pianofortes so provided to sustain
great changes of temperature and climate, as wood is entirely eliminated from those
parts which have to sustain the tension of the strings.
". . /
And in order that our said invention may be more particularly described and
ascertained; reference is hereby made to the accompanying drawings.
.
1 7
Fig. 1 is a front view of our improved wrest. A: B. C. D are the four T and
Lirons which sustain the tension of the strings, and 'a b c d are the four Tand
Lirons cast therewith, on which the string board is secured by screws at x y.
Fig. 2 is a section on the line uv of Fig. 1, the line ef shews the direction of the
tensile force of the strings, as seen by the direction of the arrows. Fig. 3 is a
section on the line rs of Fig. 1 and Fig. 4 is a section on the line
This invention possesses the following advantages
1st Facility of construction and adaptability.
of Fig. 1.
4
14"
2nd Diminution of weight of about one hundred weight and a half, as ascertained
by calculations based on careful study of the best means of avoiding all super-
abundance of material,
3rd Great strength to resist strains in consequence of the use of the T and
L form.
4th Great resistance against the influence of climate.as wood has been wholly
eliminated from those parts of the construction which are liable to strain.
Our said invention may be adapted to piano-fortes of every kind, the arrange-
ment of the frame shewn in the drawings being varied to suit the shape, as
required.

page_text: Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what
we claim is
The method of constructing iron wrest frames of T and L shaped iron, adapted
for piano-fortes of every form, substantially as described and shewn on the.
drawings.