Improvements in raonograpns.
Year: 1891

page_text: Date of Application, 5th Dec., 1891
Complete Specification Left, 5th Sept., 1892-Accepted, 22nd Oct., 1892
Improvements in raonograpns.
We, SALOMON FRANK, Mechanical Engineer, and LOUIS ROSENTHAL, Merchant;
both of Frankfort on Main, Germany, do hereby declare the nature of this
invention to be as follows:-
This invention relates to phonographs and has for its object to avoid the
difficulties incidental to phonographs and gramophones particularly as regards
delicacy of manufacture, the object being to produce efficient phonographs of
durable material.
Waves ONL
It has hitherto been generally supposed that the lightest and thinnest diaphragms
would be most efficient as they would be most susceptible to the sound
waves, and they have consequently been made proportionately small and
did not possess sufficient strength to
the sound
record
hard substance such as massive metal plates or cylinders. Conse-
quently Edison employs a very tender and in comparison with metal a very
soft wax substance on which the indented record of the sound waves is engraved
by means of a small graver or stylus. Berliner employs metal plates but the sound
waves are not engraved directly by the vibration of the diaphragm but indirectly
by means of etching or by photogravure.
In the improved instrument of this invention diaphragms of unusual size and
thickness in proportion to the rest of the instrument are used, the principle
adopted being that in order to be able to transmit sufficient mechanical force to
engrave the record of the sound waves in metal they must possess corresponding
strength. Hitherto the diaphragms of these instruments have been only from one-
third to one-tenth of a millimetre or less, whereas in the present instrument they
are from, say, two to four millimetres thick or more. They are therefore of
sufficient strength to transmit the full force of the sound waves and directly engrave
or indent the record thereof in many metals such as lead, tin, zinc, brass, copper,
iron, and the like whereby very durable resisting sharp and accurate phonograms
are obtained which may be at once employed in the same instrument to reproduce
the sounds without undergoing any treatment or preparation.
for
Another serious drawback to Berliner's apparatus is the mode of rotating
graphically recording the sound wave upon a plane surface. This is effected by
bevel gear whereby the phonogram dise is rotated with a uniform velocity. As
however the sound waves are recorded on the disc in a plane spiral, the graphic
record becomes gradually contracted as the stylus approaches the centre of the dise
since the outer convolutions are so much larger than the inner ones, the result being
that the reproduced sounds become correspondingly indistinct and lose force towards
the centre of the disc.
This evil is obviated in this improved instrument by actuating the phonogram

page_text: disc by a friction wheel which preserves a constant position in relation to the stylus
whilst it actuates the phonogram, disc at a gradually variable radius corresponding
to that of the stylus so that the angular velocity of the disc is diminished exactly
in proportion as the point at which the stylus acts recedes from the centre of the
disc thereby producing a record from which an accurate and uniform reproduction
of the sounds may be obtained.
We will now proceed to describe the improved instrument in detail..
The phonogram disc supporting table is mounted to rotate on an axis carried by a
sliding carriage traversed under the stylus by a leading screw also mounted in suid
carriage and driven by bevel gear from the phonogram table. The screw shaft is
guided by the frame and moves with the carriage by its threaded portion being
engaged by two half nuts carried by levers pivoted to the frame and acting together
so as to be thrown simultaneously into engagement with the screw, in which
position they are retained by a spring latch a spring disengaging them simul-
taneously from the leading screw when they are released from the latch which is
effected automatically when the carriage reaches the/end of its course by a stud
on the carriage striking the latch. When thus released the carriage is free to be
traversed by hand back to its starting point, the 'phonogram table being then
raised out of contact with the friction roller by an eccentric, or other, device. The
phonogram table is rotated about its axis on the carriage by the frictional contact
of a roller situated at its 'underside immediately beneath the stylus, so, that the
radial distance of said roller from the centre of the table always corresponds or
bears a fixed relation to that of the stylus, so that the part of the phonogram upon
which the stylus is for the time being acting always travels under the stylus at a
constant velocity so that the sound waves are recorded uniformly over the whole
phonogram disc. The latter is made preferably of zinc and is clamped to its
supporting table by a central nut. The sound receiving and recording diaphragm
is clamped marginally to a concave or casing having at back a central tube which
is held in a fixed clamp and to which the trumpet-shaped mouth piece is connected.
To the centre of the diaphragm is connected by a swivel joint one arm of a bell
crank lever fulcrumed to the diaphragm casing at one side, the other arm carrying
the stylus which is made of the hardest material. The advantage of this lever over
those heretofore used is that the transmission to the diaphragm of vibrations of the
stylus caused by the working of the instrument or by inequalities of the phonogram-
disc is prevented.
When large diaphragms are used a strong check spring is applied to act on the
diaphragm at its centre-joint to prevent false or disturbing oscillations. The un-
usual stoutness of the diaphragm enables the stylus to indent the record of the most
delicate sound waves directly in the phonogram disc in which the sound wave
record is produced in the form of a close spirally wound sinuous or serpentine line
or furrow.
The reproduction of the sound is effected by means of another
diaphragm similar to the large receiving diaphragm supported by a swing arm.
As it has not the same mechanical work to perform as the receiving diaphragm,
it may be made of much smaller dimensious, the stylus being carried by an arm
jointed to the centre of the diaphragm which is so held by its supporting arm that
when brought into position over the phonogram the stylus and arm will be at an
acute angle to the plane thereof. When this diaphragm is brought into use the
receiving diaphragm is turned round in its supporting clamp so as to raise its
stylus out of operative contact with the phonogram dise.
Dated this 5th day of Dagomban 1901

page_text: improvements in rnonographs.
We, SALOMON FRANK, Mechanical Engineer, and Louis Rosenthal, Merchant.
both of Frankfort-on-Main, Germany, 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 phonographs and has for its object to avoid the difficulties
incidental to phonographs and gramophones, particularly as regards delicacy of
manufacture, the object being to produce efficient phonograms of durable material:
It has hitherto been generally supposed that the lightest and thinnest diaphragms
would be most efficient as they would be most susceptible to the sound waves, and
they have consequently been made proportionally small and did not possess
sutncient strength to record the sound waves on a hard substance such as solid metal
plates or cylinders. Consequently, Edison employs a very tender and, in comparison
with metal, a very soft medium, namely wax, on which the indented record of the
sound waves is engraved by means of a small graver or stylus. Berliner employs
metal plates, but the sound waves are not engraved directly by the vibration of the
diaphragm, but indirectly, by means of etching or by photogravure.
The inventors have discovered that the vibrations of the diaphragm are, for trans-
mitting purposes, not prejudicially affected by thickening the diaphragm, or in
other words by replacing the diaphragm by a solid metal plate. They further
discovered that there is energy enough in the acoustic waves to perform such work
as engraving a hard metal plate and that this energy might be caught by sound-
receiving plates of sufficient thickness and volume and they further discovered that
the strength imparted to such plates by their shape is essential for the work they
are to perform. As the pressure existing between the graver and the plate to be
engraved is transmitted (through the lever) to the sound receiving plate, the
vibrations of the latter will be changed from their right acoustical form by the
bending of the plate in consequence of the pressure exerted on it. A plate of
great volume and strength is able to receive great energy from the vibrations of the
air (if rightly led to the plate) and is able to transmit the vibrations unchanged
even by great resistances to them.
In the improved instrument of this invention, therefore, diaphragms of unusual
size and thickness are used, the principle adopted being that in order to be able to
transmit sufficient mechanical force to engrave the record of the sound waves in
metal, they must possess corresponding strength. Hitherto, the diaphragms
of these instruments have been only from one-third to one-tenth of a millimetre.
or less, in thickness, whereas in the present instrument they are from, say, two to
four millimetres thick, or more. They are, therefore, of sufficient strength to
transmit the full force of the sound waves and directly engrave or indent the
record thereof in many metals, such as lead, tin, zine, brass, copper, iron, and even
steel and the like, whereby very durable, resisting, sharp, and accurate phonograms
are obtained which may be at once employed in the same instrument to reproduce
the sounds without undergoing any treatment or preparation.
As.
Another serious drawback to Berliner's apparatus is the mode of rotating it for
graphically recording the sound wave upon a plane surface. This is effected by
bevel gear whereby the phonogram disc is rotated with a uniform velocity.
however, the sound waves are recorded on the disc in a flat spiral, the graphic record
becomes gradually contracted as the stylus approaches the centre of the disc, since
the radius of the outer convolutions is so much greater than that of the inner ones.
the speed varies correspondingly, the result being that the sounds become

page_text: correspondingly indistinct and lose force when reproduced from near the centre of
the disc.
This evil is obviated in this improved instrument by actuating the phonogram
dise by a friction wheel which preserves a constant position in relation to the
stylus, whilst it actuates the phonogram disc at a gradually variable radius
corresponding to the radial distance of the stylus from the centre of the disc so
that the angular velocity of the disc is diminished exactly in proportion as the point
at which the stylus acts recedes from the centre of the disc thereby producing a
record from which an accurate and uniform reproduction of the sounds may be
obtained.
We will now proceed to describe the improved instrument in detail, with
reference to the accompanying drawings, forming part of this specification, wherein
Figure 1 is a plan, Figure 2 a vertical section, and Figure 3 a side elevation, of
the improved instrument. Figure 4 shows a special arrangement of the receiver
diaphragm, and Figure 5 shews the reproducing diaphragm carried by the arm,
shewn broken off in the first three figures. The same letters of reference denote
like parts in all the figures.
A is the frame, B is a carriage mounted to slide therein, and C is the phonogram
dise-supporting table mounted to rotate on an axis carried by the sliding carriage B.
said table C being traversed under the stylus as the table is rotated by a leading
screw F mounted to turn in a bearing in said carriage B and driven by bevel
gear D, E, from the phonogram table C, the wheel 1) being fast on the axis of the
table and wheel E fast on the screw-shaft. The screw-shaft is partly plain and
slides in a guide bearing in the frame A and is furnished with collars H H between
which the carriage B is beld so as to cause the carriage to be traversed in its guides
by the threaded portion of the screw F being engaged by two half-
nuts J, J, carried by levers K, L. pivoted to the frame A at M, M,
and acting together SO as, by means of handle N. on lever L. to
be thrown simultaneously into engagement with the screw in which position the
nuts are retained by a spring latch O, aspring (acting directly on lever K and
through it on the turned up tail end of lever L) disengaging the half-nuts carried
by said levers simultaneously from the leading screw F when the levers are
released from the latch O which is effected automatically, when the carriage B
reaches the end of its course, by a stud P on the carriage striking the latch 0.
When thus released the carriage will remain stationary but the table C will be free
to revolve. The phonogram table C is rotated about its axis on the carriage B by
the frictional contact of a roller Q on shaft S driven by a pulley R, said friction
roller being situated at the underside of table C immediately beneath the stylus f
so that the radial distance of said roller Q from the centre of the table C always
corresponds or bears a fixed relation to that of the stylus, so that the part of the
phonogram upon which the stylus f is for the time being acting always travels
under the stylus at a constant velocity, the table C revolving proportionally slower
as the stylus approaches its periphery. so that the sound waves are recorded
uniformly over the whole phonogram disc. The phonogram disc T is made
preferably of zinc and is clamped to its supporting table C by a central nut U. The
sound receiving and recording diaphragm Y is clamped marginally by a ring
and screws to a massive concave back or casing W attached to a central tube X which
is held in a fixed clamp V supported on the base plate Z and to which the trumpet-
shaped mouth piece is connected. To a stud eat the centre of the diaphragm Y is
connected one arm of a bell crauk lever d, fulcrumed to a stud .h fixed on the
diaphragm clamping ring at one side, the other arm being provided with a
clamp carrying the stylus f, which is made of the hardest material. The lever
works in a plane parallel to the phonogram disc and the advantage of this lever
over those heretofore used is that the transmission to the diaphragm of vibrations
of the stylus caused by the working of the instrument or by inequalities of the
phonogram dise is prevented.
11.
When large diaphragms are used, a strong check spring µ (Figure 4) may be

page_text: applied to act on the diaphragm Y at its centre joint, to prevent false or disturbing
oscillations. The unusual stoutness of the diaphragm enables the stylus to engrave
the record of the most delicate sound waves directly in the phonogram disc.
As
the carriage B and dise T are slowly drawn forward by the leading screw F during
the rotation of the disc T, the sound waves received by the mouth-piece and
diaphragm are recorded in the form of a close spirally wound sinuous or serpentine
line or furrow. Directly the stylus approaches the periphery. of the disc, the
nuts J are unclasped by the pin P disengaging latch O so that the carriage B
remains stationary while the stylus describes a circular furrow upon the disc. The
reproduction of the sound is effected by means of another diaphragm t, shewn in
Figure 5, similar to the receiving diaphragm Y, supported by a swing arm u. As
however this diaphragm has not the same mechanical work to perform as the
receiving diaphragm, it may be made of much smaller dimensions, the stylus being
carried by an arm jointed to the centre of the diaphragm which is so held by its
supporting arm that when brought into position over the phonogram disc T the
stylus and arm will be at an acute angle to the plane thereof. When this
diaphragm is brought into use the receiving diaphragm Y is turned round in its
supporting clamp V by slacking screw m so as to raise its stylus f out of operative
contact with the phonogram disc. The stylus of the reproducing diaphragm tis
then brought into contact with the phonogram disc by swinging arm over said
disc, having previously run the carriage back to its starting position, the table C
being raised out of contact with roller Q during this movement. by turning an
eccentric pin n which acts on the lower end of the axis of the table C and raises
it in its bearing in the carriage, and then lowered again into contact with roller Q.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. A phonograph or gramophone provided with a sound receiving diaphragm
of such area and thickness that the stylus connected thereto and operated thereby
is capable of directly engraving the record, of the sound waves in a plate of metal
or other comparatively. hard material, without the resistance of the material being
able to bend the diaphragm or affect its vibrations, as described.
2. The herein described phonograph or gramophone characterized by the com-
bination of a rigid sound receiving diaphragm, means to transmit its vibrations to a
stylus, and means to press the stylus constantly against the engraving plate, as
described.
3. In a phonograph or gramophone, the combination, with the sound receiving
diaphragm, of a pressure spring applied to act on the centre of the diaphragm and
impart an initial stress or tension thereto for the purpose of increasing its
sensitiveness to sound, as described.
D
1
1000
S. FRANK,
L. ROSENTHAL.
By A. M. & Wm. Clark,
Chartered Patent Agents, 53, Chancery Lane, London.