Adjustable Tension Device for Phonograph Diaphragms.
Year: 1897

page_text: Date of Application, 18th Aug., 1897
Complete Specification Left, 28th Mar., 1898--Accepted, 14th May, 1898
PROVISIONAL SPECIFICATION.
Adjustable Tension Device for Phonograph Diaphragms.
We, PHILIPP VON WOUWERMANS, Engineer, THEODOR FISCHER, Merchant, both
of I Wallfischgasse 4, MAX RAPHAEL. KOIIN, Merchant, of I Schollenring, 23, and
IGNAZ PULAY, Gentleman, of IX Mullnergasse 3, all of Vienna, Austria, do hereby
declare the nature of this invention to be as follows:-
The experience heretofore obtained with phonographs has shown that the tension
of the diaphragm, that is to say, the pressure with which the recording knife cuts
into the wax roller, must, in the case of spoken language, be different to that for
recording singing, whistling and music. Also that when reproducing from a
record by means of the reproducing pin, shrill tones, both spoken and musical,
are capable of being rendered clearer or softer by producing a greater tension of
the diaphragm.
Now, the apparatus which forms the subject of the present invention and which
is designed to effect in a perfect manner this two-fold object, produces a continual
intimate contact of the recording pin, or of the reproducing pin, with the roller, and
also imparts to the diaphragm a certain tension which can be adjusted to suit
requirement. This apparatus is characterized by the fact that the pivot of the
lever which connects the diaphragm with the recording pin or with the repro-
ducing pin, is loaded by a weight which is rendered capable of movement by means
of a parallel motion, so that when the body of the diaphragm is adjusted relatively
to the roller by means of a regulating device, the pressure of the pin upon the roller,
that is to say, the tension of the diaphragm, will be varied.
Fig. 1 of the accompanying illustrative drawings shows partly in vertical sec-
tion and partly in elevation one construction of tension apparatus according to
this invention; Figs. 2 and 3 show the loading device in two other different posi-
tions; and Fig. 4 illustrates the same in combination with another arrangement
of lever for the recording pin or the reproducing pin.
In the device for holding the diaphragm, such for example, as the pressing ring a,
there are arranged parallel to the roller axis and opposite to each other, two
pivots upon which are mounted, so as to be capable of turning thereon, two
radius or guide links c which are connected together by a cross-piece d of deter-
mined weight, and of a length exactly equal to the distance between the pivots.
This cross-piece, which is suspended from the radius links, and which, together
with the latter and with the pressing ring, forms a parallelogram of levers, carries
the two-armed lever f which holds at one end the recording knife (or reproducing
pin) g, and is connected at its other end by means of a small hook h to a ring i
which is fixed to the diaphragm k.
Fig. 1 shows that position of the parallelogram in which the cross-piece d bears
with its whole weight upon the pivot of the knife or pin lever f and consequently
tightens the diaphragm so as to form an intimate contact between the knife or
recording pin g and the roller. On increasing the distance between the diaphragm.
and the cross-piece d by rotating the radius rods c downward, the pressure of the
cross-piece upon the lever pivot becomes continually smaller (Figs. 2 and 3). When,

page_text: the radius rods have been turned down to such an extent as to be at right angles to
the cross-piece, the pressure, that is to say, the tension of the diaphragm becomes
nil, and on further rotation beyond the nil or zero position, an actual lifting action
will take place, until the radius links become vertical.
Now, for the purpose of enabling the diaphragm to be moved more or less away
from the roller, and thereby of imparting a different position to the radius links c
corresponding to the desired tension of the diaphragm, the body carrying the
diaphragm is rendered movable by means of a regulating device which may con-
sist, for example, as shown in Fig. 1 of a lever arm n which holds the body m
and is arranged to oscillate about the axis 7, and which can be adjusted by means
of a regulating screw ? acting upon its shoulder or short arm o. The regulating
device may also consist of a fixed guide rod, along which the diaphragm body can
be screwed or fixed higher or lower, as desired.
Obviously, the tension device herein before described can also be connected with a
one-armed knife lever or contact pin lever f, as shown in Fig. 4.
In this manner, the transmitted vibrations can be increased by choosing a suit-
able ratio between the length of the lever arms in a well-known manner.
When compared with the loading weight (which in phonographs heretofore
employed has been constructed as a one armed lever capable of being oscillated
about a fixed point) for the pivot of the knife lever or contact pin lever, the
apparatus herein described has the great advantage that the entire weight is com-
pelled to share the vibrations, because it is moved parallel to itself and it can there-
fore oppose a considerably greater resistance to the said vibrations.
101 1
A
1007
Adjustable Tension Device for rnonograpп Diaphragms.
We, PHILIPP VON WOUWERMANS, Engineer, THEODOR FISCHER, Merchant, both
of I Wallfischgasse 4, MAX RAPHAEL KOHN, Merchant, of I Schollenring 23, and
IGNAZ PULAY, Gentleman, of IX Mullnergasse 3, all of Vienna, Austria, 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:―
The experience heretofore obtained with phonographs has shown that the tension
of the diaphragm, that is to say, the pressure with which the recording knife cuts
into the wax roller, must, in the case of spoken language, be different to that for
recording singing, whistling and music. Also that when reproducing from a
record by means of the reproducing pin, shrill tones, both spoken and musical,
are capable of being rendered clearer or softer by producing a greater tension of
the diaphragm.
Now, the apparatus which forms the subject of the present invention and which
is designed to effect in a perfect manner this two-fold object, produces a continual
intimate contact of the recording pin, or of the reproducing pin, with the roller, and
also imparts to the diaphragm a certain tension which can be adjusted to suit
requirement. This apparatus is characterized by the fact that the pivot of the
lever which connects the diaphragm with the recording pin or with the repro-
ducing pin, is loaded by a weight which is rendered capable of movement by means
of a parallel motion, so that when the body of the diaphragm is adjusted relatively
to the roller by means of a regulating device, the pressure of the pin upon the roller,
that is to say, the tension of the diaphragm, will be varied.

page_text: Fig. 1 of the illustrative drawings filed with our Provisional Specification shows
partly in vertical section and partly in elevation, one construction of tension appa-
ratus according to this invention; Figs. 2 and 3 show the loading device in two
other different positions; and Fig. 4 illustrates the same in combination with
another arrangement of lever for the recording pin or the reproducing pin.
In the device for holding the diaphragm, such for example, as the clamping
ring a, there are arranged parallel to the roller axis and opposite to each other, two
pivots upon which are mounted, so as to be capable of turning thereon, two
radius or guide links c which are connected together by a cross-picce d of deter-
mined weight, and of a length exactly equal to the distance between the pivots.
This cross-piece, which is suspended from the radius links, and which, together
with the latter and with the clamping ring, forms a parallelogram of levers, carries
the two-armed lever f which holds at one end the recording knife (or reproducing
pin) g, and is connected at its other end by means of a small hook to a ring i,
which is fixed to the diaphragm k.
Fig. 1 shows that position of the parallelogram in which the cross piece & bears
with its whole weight upon the pivot of the knife or pin lever f and consequently
tightens the diaphragm so as to form an intimate contact between the knife or
recording pin g and the roller. On increasing the distance between the diaphragm
and the cross-piece d by rotating the radius rods c downward, the pressure of the
cross-piece upon the lever pivot becomes continually smaller (Figs. 2 and 3).
When the radius rods have been turned down to such an extent as to be at right
angles to the cross-piece, the pressure, that is to say, the tension of the diaphragm
becomes nil, and on further rotation beyond the nil or zero position, an actual lift-
ing action will take place, until the radius links again become vertical.
Now, for the purpose of enabling the diaphragm to be moved more or less away
from the roller, and thereby of imparting a different position to the radius links c
corresponding to the desired tension of the diaphragm, the diaphragm casing is
rendered movable by means of a regulating device which may consist, for example,
as shown in Fig. 1 of a lever arm n which holds the casing m and is arranged to
oscillate about the axis 1, and which can be adjusted by means of a regulating
screw pacting upon its shoulder or short arm o. The regulating device may also
consist of a fixed vertical guide rod, along which the diaphragm casing can be
screwed or fixed higher or lower, as desired.
Obviously, the tension device herein before described can also be connected with
a one-armed knife lever or contact pin lever f, as shown in Fig. 4.
The transmitted vibrations can be increased by choosing a suitable ratio between
the length of the lever arms in a well-known manner.
When compared with the loading weight (which in phonographs heretofore
employed has been constructed as a one-armed lever capable of being oscillated
about a fixed point) for the pivot of the knife lever or contact pin lever, the appa-
ratus herein described has the great advantage that the entire weight is compelled
to share the vibrations, because it is moved parallel to itself and it can therefore
oppose a considerably greater resistance to the said vibrations.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1. In a phonograph, for the purpose of obtaining practically constant and
intimate contact and uniform pressure between the reproducing pin or the record-
ing knife and the phonogram-roller, an adjustable diaphragm tension device
comprising a weight that carries the lever of the recording knife or of the repro-
ducing pin, is suspended from the diaphragm-holder by means of two links and
forms in conjunction with the diaphragm-holder and the said links a jointed
parallelogram the arrangement being such that each change in the position of the
diaphragm-holder will produce a change of position of the said weight parallel.
relatively to the diaphragm-holder, substantially as set forth.

page_text: 2. In combination with a diaphragm tension device comprising a weight carry-
ing the lever of the recording knife or of the reproducing pin and jointed to the
diaphragm-holder by means of two links c so as to form therewith a parallelogram,
a regulating device whereby the position of the diaphragm casing relatively to the
phonogram-roller can be varied or controlled, the said regulating device comprising
a lever connected to the diaphragm casing and capable of an oscillating motion
and a set screw acting upon the shoulder or short arm of the said lever arm in such
a manner as to produce a displacement of the same and allow of the required change
of position of the parallelogram, substantially as set forth.
3. In a phonograph, apparatus for varying the tension of the diaphragm, con-
structed, arranged and operating substantially as described and shown.
Dated this 28th day of March 1898.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.