Improvements in Zither-banjos.
Year: 1896

page_text: Date of Application, 3rd July, 1896
Complete Specification Left, 2nd Sept., 1896-Accepted, 14th Nov., 1896
PROVISIONAL SPECIFICATION.
Improvements in Zither-banjos.
I, ALFRED DAVIES CAMMEYER, of 59 Piccadilly, London, W., Teacher of the
Banjo, do hereby declare the nature of this invention to be as follows:-
My invention relates to zither-banjos, and has for its object an improvement in
the tone of these musical instruments by a novel construction of their sound-
boxes.
The wood back, circular wood rim, and circular wood ring at the top edge of
the casing of a zither-banjo, together form the sound-box; and my first improvement
consists in the addition to the sound-box of a thin inner diaphragm, preferably of
wood, which may or may not follow the contour of the back. The diaphragm and
the back may be entirely disconnected with each other, or joined together at
their edges, but in either case enclosing an air-chamber between them. The
diaphragm may or may not be perforated with a hole or holes.
My second improvement consists in the addition to the sound-box of a thin
circular inner rim, preferably of wood, concentric with the outer rim, but smaller
in diameter so as to leave an air-channel between the two. It is attached at its
upper edge to the circular wood ring, and may or may not be perforated with
holes.
I may combine these two improvements of a diaphragm and circular inner rim,.
the whole casing of the sound-box of a zither-banjo, thus being made hollow.
Dated this 3rd day of July 1896
ALFRED DAVIES CAMMETER.
I, ALFRED DAVIES CAMMEYER, of 59 Piccadilly, London, W., Teacher of the
Banjo, 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 zither-banjos, and has for its object an improvement in
the tone of these musical instruments by a novel construction of their sound-
boxes.
To illustrate my invention I have annexed a sheet of drawings, throughout the
several views of which, like letters indicate like parts.
The sound-box of a zither-banjo, as heretofore constructed, consists, see Figure 1,
which is a section through the centre line of sound-box, and Figure 2, which is a
plan of the same, of the back, A; the circular rim, B; and the thicker part of
rim at top edge which I call the ring, C; usually all of wood.
On these drawings I have also indicated some portion of the parts of the
instrument immediately connected with the sound-box, such as :-The supporting
brackets, D; the circular metal rim, E; straining hoop, F; with its fittings; the
arm G; fingerboard H; skin head I and stock J; the natures of all of which
are well known.

page_text: My first improvement consists in the addition to the sound-box of a vibratile
diaphragm, K, leaving an air-chamber L between itself and the back, to give
greater resonance to the sounds produced on the instrument. This diaphragm is
preferably of maple or other wood, from about 3 of an inch to of an inch in
thickness; but I do not limit myself to wood, and may use any other suitable
material. The diaphragm may be flat, or follow the contour of the back, or take
another contour; and may be joined at its edge either to the edge of the back, A;
or to the rim, B; and may have a hole, M, or holes, to modify the quality of the
tone of the instrument as desired.
My second improvement consists in the addition to the sound-box of a circular
inner rim, concentric with the outer rim, but smaller in diameter, so as to leave a
reverberant air-channel between the two. It is preferably of holly or other wood,
built up of three thicknesses, each about of an inch in thickness, but I do not
limit myself to wood and may use any other suitable material. I attach this inner
rim at its top edge to the ring, preferably by a glued joint in the case of wood,
and it may be of sufficient depth to meet the back and be joined to it, or it may
be of a lesser depth. It may be perforated by a hole or holes as desired to modify
the toue of the instrument. This inner rim will of course be pierced by the stock
where necessary.
My third improvement consists in the combination of my first and second
improvements, and is shewn in Figure 3, which is a section through the centre line
of sound-box; Figure 4, which is a half-plan of the same, and Figure 5, which is
a half-section on line X, X of Figure 3.
The parts shewn in these figures which are similar to parts in Figures 1 and 2
are respectively indicated by the same letters as before. N is the inner rim;
O the air-channel and P a sound-hole in the inner rim N.
In this case I may attach the edge of the diaphragm K to the lower edge of the
inner rim N, preferably by a glued joint in the case of both being of wood.
It will be seen that by this improvement, the whole casing of the sound-box of a
zither-banjo is made hollow; there being an air-chamber between the diaphragm
and back and an air-channel between the inner and outer rims; the resonance of
the instrument being thereby greatly increased.
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 :-
1. In the construction of the zither-banjo, the addition. to the sound-box of an
inner rim leaving an air-channel between it and the outer rim, substantially as
herein described.
2. In the construction of the zither-banjo, a sound-box the casing of which is
made hollow by the addition of a diaphragm and an inner rim, substantially as
herein described.
Dated this 2nd day of September 1896
ALFRED D. CAMMEYER.