Improvements in Phonographs
Year: 1899

page_text: Date or Application, 4th Sept., 1899-Accepted, 4th Nov., 1899
COMPLETE SPECIFICATION.
Improvements in Phonographs,
I, CARL SPÄTII, of 10, Schmausengarten Strasse, Nuremberg, in the Empire
of Germany, Electrician, 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: —
This invention relates to a diaphragm guide in phonographs. As is well
known in phonographs the diaphragm must be so guided that it may be pro-
gressively adjusted to any point of a receiving cylinder.
This takes place either by the cylinder being fixed and the diaphragm being
connected with a screw which moves it forward on the rotation of the cylinder
or the diaphragm is fixed and the cylinder is mounted on a screw, so that the
fixed diaphragm describes a spiral line over the progressively revolved cylinder.
The best known form of the cylinder is a metal roller with or without ribs
over which tinfoil is stretched which receives the impressions from the diaphragm,
or a smooth wax cylinder.
As however the fine thread for guiding the roller requires for the diaphragm
also too complicated a construction, this invention shows a means of guiding
the diaphragm which is extraordinarily simple and works excellently, yielding
a surprising effect, whilst any spiral or screw guidance is avoided.
In the accompanying drawings:-
-
Fig. 1 is a front view of the improved phonograph and Fig. 2 a side view of
the same, whilst Fig. 3 shows a detailed view of a hinge pin and Figs. 4 and 5
are also details of construction.
The standard or support for the interchangeable wax cylinder b which may
be suitably mounted, and for the fly wheel c is fixed on a bed plate or foundation a,
a crank or handle d being attached to the fly wheel c. The cylinder will thus
on being rotated always move in the same plane. The standard or upright e
is also fixed on the support a, which standard e has a recess at the top for receiving
a hinge pin f, see Fig. 3.
The long lever arm g is movable on the hinge of this pin and carries at its
other end a diaphragm h and a trumpet or resonance funnel i directly connected
with it. The diaphragm itself may be exchanged for recording or reproducing
conversation. The trumpet i may also be removed.
A kind of flat or square thread, as shown in Fig. 5, is cut in the wax cylinder
itself. In this thread a pin k on the diaphragm is automatically guided on
the rotation of the cylinder b as it is revolubly mounted on the hinge pin f.
The thread itself has the tops or ridges very broad and the bottoms or recesses
very narrow; the latter only exist for guiding the pin & between them.
It would not be possible to use a sharp screw thread for this object, as the
pin would at the same time eat its way in.
If the diaphragm h be set at the commencement of the cylinder b, then, on
the latter being turned, the pin will be automatically from there projected over

page_text: the roller, and will inscribe on the wax the words spoken into the trumpet, and
the sound waves.
C
When the cylinder is fully scribed, the diaphragm is again returned to the
commencement, and the cylinder on being rotated in a similar direction, repro-
duces as words what was recorded on it. For recording on the roller and for
reproducing, in practice different diaphragms with suitable finer or coarser points
are used. The wheel is used as a fly wheel in order to obtain an even rotation.
In order to allow of the roller or cylinder being frequently used, the sound
waves inscribed thereon must be destroyed. This is done by scraping the roller
with a turning tool which has teeth coinciding with the thread on the roller.
Such a turning tool is shown in Fig. 4, u being the tool itself and a the piece
of felt or a wool flap for smoothing down the roller afterwards.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is: -
A diaphragm guide for phonographs characterised by the membrane, which
is directly connected with the sound trumpet or resonance funnel being freely
and movably mounted on a lever and guided by a diaphragm pin in flat or square
screw threads formed in a wax cylinder revolving in the same plane, substantially
as herein before described.