An Improved Chromatic Tymbal or Kettle-drum.
Year: 1897

page_text: An Improved Chromatic Tymbal or Kettle-drum.
I, GUSTAVE FRANTZ LYON, of 22, Rue Rochechouart, Paris, in the Republic of
France, Engineer, do hereby declare the nature of my invention to be as
follows:-
My invention relates to an improved chromatic tymbal or kettle-drum and has
for its object to provide improved means for effecting variations in the extent or
area of the vibrating surface of a single membrane or diaphragm of a kettle-drum,
a special feature being that these different areas may be circular in shape, and at all
times limited by cylindrical parts or rings arranged on either side of the parchment
or the like diaphragın, which parts are adapted to be moved into contact with the
same; in performing which movements they slide either along identical generating
lines, or helically, about the axis common to such cylinders, but so that the terminal
sectional areas of the said cylinders always continue parallel both to each other and to
the diaphragm which they are to hold between them.
In kettle-drums, as hitherto constructed, the number of variations is varied by
stretching the parchment more or less by means of screws, which, as a rule, are seven
in number, and arranged to act upon a stretching ring or hoop; with the result that
the parchment, in consequence of its being stretched out along the outer surface of
the tymbal, and of its bearing upon the edge of the said tymbal, has the degree of
its tension raised to such an extent, as to cause the number of vibrations of the
parchment to increase.
Hitherto, all the arrangements devised with a view to obtaining chromatic kettle-
drums have had for their object so to combine or connect the tension screws as to
enable them to be operated simultaneously, either by the direct agency of the hand,
or through the medium of pedals. But it has been impossible to provide any
strictly reliable indicator or gauge, exactly showing the notes corresponding to the
various degrees of pressure, applied through the medium of the screws, as it is a well.
known fact that the tension of the vellum diaphragms is pre-eminently dependent -
upon atmospheric conditions, and is apt to vary within intervals of one-fourth, or
even one-fifth in the pitch to which the kettle-drum has been attuned. The vellum
is, therefore, in a constantly varying condition, owing to which but a minute
fraction of a turn of the screws will at one time produce an effect equivalent to that.
which, at other times, it may take a number of complete turns to achieve. Hence
it is that none of the existing kettle-drums or tyınbals have so far yielded any
satisfactory results.
Take the case of a tymbal, the diaphragm whereof, to simplify illustration, has
been tuned to the second f on the piano, by means of the screw arrangement now in
use. By the well known laws governing the relation between the varying area of
the diaphragm surface and the number of vibrations, it suffices to reduce such area
in a predetermined proportion to obtain the different notes required, provided the
degree of tension of the diaphragm continues unaltered.
Now the main object of this invention is to ensure compliance with the last
mentioned condition, the arrangement which enables this result to be obtained

page_text: consisting of concentric cylindrical rings or hoops disposed above and below the
diaphragin. The portions of the rings facing the diaphragm are slightly rounded off;
and the diameters of both rings of each pair are alike. Each pair of rings thus
controls that portion of the diaphragm area which corresponds to a given note, and,
in order to produce this note, it is only necessary by the employment of any suitable
mechanism, to move the two corresponding concentric rings close together, so as to
bring them into contact with either side of the diaphragm at the same instant.
I will describe a tymbal or kettledrum constructed according to this invention but
I do not limit myself to the precise details.
In the frame of the tymbal or kettledrum a diaphragm is stretched by means of
au iron ring or hoop and a screw and nut. Above and below the said frame are
fixed circular dises of any suitable metal, such as aluminium, for example. These
discs are provided with circular grooves, in which the cylindrical rings or hoops are
embedded. In order to ensure the simultaneous and uniform motion of the sets of
hoops, two levers, are employed preferably connected together by a rod and provided
with repelling-springs for moving such levers apart.
The kettle-drum has a symmetrical vertical axis passing through the centre. For
each one set or pair of rings or hoops there are, therefore, two levers capable of being
operated by means of a single pedal.
In order that there may be perfect uniformity both in the upward movement of
the lower ring or hoop and in the downward movement of the upper ring or hoop,
there should be between the lever arms a ratio denoted by the equation,
in which a and b are the two arms of the lever operating the upper ring, and d
and dc the two arins of the lever operating the lower ring; the solution of
which, viz.
is here adopted.
a = 26
C = d
In this example it has been assumed that each ring or hoop is supported, or
compressed, only at two diametrically opposite points. There might, however, be
three or more points of connection, if required, being all acted upon by one single
pedal and each pair of combined hoops should in all cases be located above and below
the parchment, respectively.
As already stated, the invention is not dependent upon the arrangement employed
for causing the rings or hoops to rise and descend; thus they might be drawn close
together by the employment of pneumatic tubes placed above the upper rings and
below the lower rings, such tubes being inflatable whenever required by injecting air
for any other fluid into them.
1000
is here adopted.
In this example it has been assumed that each ring or hoop is supported, or
compressed, only at two diametrically opposite points. There might, however, be
three or more points of connection, if required, being all acted upon by one single
pedal and each pair of combined hoops should in all cases be located above and below
the parchment, respectively.
As already stated, the invention is not dependent upon the arrangement employed
for causing the rings or hoops to rise and descend; thus they might be drawn close
together by the employment of pneumatic tubes placed above the upper rings and
below the lower rings, such tubes being inflatable whenever required by injecting air
for any other fluid into them.
CREEPIK
-6 ו י
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
I, GUSTAVE FRANTZ LYON, of 22, Rue Rochechouart, Paris, in the Republic of
France, Engineer, do hereby declare the nature of this invention and in what manner 45

page_text: the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention relates to an improved chromatic tymbal or kettle-drum, and has for
its object to provide improved means for effecting variations in the extent or area of
the vibrating surface of a single membrane or diaphragm of a kettle-drum, a special
feature being, that these different areas may be circular or rectangular in shape, and
at all times limited by rings or cylindrical parts arranged on either side of the parch-
ment or the like diaphragm, which parts are adapted to be moved into contact with
the same, in performing which movements they slide either along identical
generating lines, or helically, about the axis common to such cylinders, but so that
the terminal sectional areas of the said cylinders always continue parallel both to
each other and to the diaphragm which they hold between them.
In kettle-drums, as hitherto constructed, the number of vibrations is varied by
stretching the parchment more or less by means of screws, which, as a rule, are seven
in number, and arranged to act upon a stretching ring or hoop; with the result that
the parchment, in consequence of its being stretched out along the outer surface of
the tymbal, and of its bearing upon the edge of the said tyınbal, has the degree of its
tension raised to such an extent, as to cause the number of vibrations of the
parchment to increase.
Hitherto all the arrangements devised with a view to obtaining chromatic kettle-
drums have had for their object so to combine or connect the tension screws as to
enable them to be operated simultaneously, either by the direct agency of the hand,
or through the medium of pedals. But it has been impossible to provide any strictly
reliable indicator or gauge, exactly showing the notes corresponding to the various
degrees of pressure applied through the medium of the screws, as it is a well known
fact that the tension of the vellum diaphragms is pre-eminently dependent upon
atmospheric conditions, and is apt to vary within intervals of one-fourth, or even.
one-fifth in the pitch to which the kettle-drum has been attuned. The vellum is,"
therefore, in a constantly varying condition, owing to which but a minute fraction of
a turn of the screws will at one time produce an effect equivalent to that which, at
other times, it may take a number of complete turns to achieve. Hence it is that
none of the existing kettle-drums or tymbals have so far yielded satisfactory results.
Take the case of a tymbal, the diaphragm whereof, to simplify illustration, has
been tuned to the second f on the piano, by means of the screw arrangement now in
use. By the well-known laws governing the relation between the varying area of the
diaphragın surface and the number of vibrations, it suffices to reduce such area in a
predetermined proportion to obtain the different notes required, provided the degree
of tension of the diaphragm continues unaltered.
Now the main object of this invention is to ensure compliance with this last-
mentioned condition for which either of the following arrangements may be used.
The first arrangement according to my invention consists of concentric rings or
hoops disposed above and below the diaphragm. The portions of the rings facing the
diaphragm are slightly rounded off, and the diameters of both rings of each pair are
alike. Each pair of rings thus controls that portion of the diaphragm area which
corresponds to a given note; and, in order to produce this note, it is only necessary-
by the employment of any suitable mechanism-to move the two corresponding
concentric rings close together, so as to bring them into contact with either side of the
diaphragin at the same instant.
The second arrangement consists in the application of my invention to rectangular
tymbals or kettle-drums, in this case the diaphragm is held between two cylinders
parallel to the ends of the rectangle and capable of movement in the direction of the
length of the same.
And in order that my invention may be clearly understood, I will now describe
the same with reference to the accompanying drawings, in which the mechanisın
employed is represented by way of example only.
Figure 1 of the drawings is a diametrical vertical section of part of a circular

page_text: tymbal or kettledrum constructed according to my invention taken on a line passing
through one of the screws for effecting the initial adjustment; and
Figure 2 is a partial plan of the same.
Figure 3 shews a rectangular tymbal or kettledrum according to my invention in
side elevation and
Figure 4 is a vertical section of the same taken on the line A. B. Figure 3.
Referring first to the tymbal shewn in Figures 1 and 2 over the frame 1, 2
thereof a diaphragm 3 is stretched by means of an iron ring or hoop 4 and a
screw and nut 5. Above and below the said frame are fixed circular discs 6, 61,
of any suitable metal, such as aluminium, for example. These discs are provided
with circular grooves, in which cylindrical rings or hoops 7 are embedded. 'In
order to ensure the simultaneous and uniform motion of the sets of rings or
hoops, two levers, such as are shown at 8 and 9 are employed, pivotted at 10
and 11, connected together by the rod 12 and provided with repelling springs 13, 13¹
for moving such levers apart.
The tymbal or kettle-drum has a symmetrical vertical axis passing through its
centre and for each one set or pair of rings or hoops, there are, therefore, two
levers 9, capable of being operated by means of a single pedal which may be
arranged in any convenient manner not shown in the drawings.
In order that there may be perfect uniformity both in the upward movement
of the lower ring or hoop and in the downward movement of the upper ring or
hoop, there should be between the lever arms a relation denoted by the equation
is here adopted.
In this example it has been assumed that each ring or hoop is supported, or
compressed, only at two diametrically opposite points. There might, however, be
three or more points of connection, if required, all being acted upon by one single
pedal, and each pair of combined hoops should in all cases be located above and
below the parchment, respectively.
As already stated, the invention is not dependent upon the arrangement employed
for causing the rings or hoops to rise and descend; thus they might be drawn close
together by the employment of pneumatic tubes placed above the upper rings and
below the lower rings, such tubes being inflatable whenever required by injecting
air or other fluid into them.
The rectangular tymbal shewn in Figures 3 and 4 constructed according to my
invention is a modification of the preceding arrangement and in principle is precisely
similar, as in this case also there is a reduction of the vibrating surface of the
diaphragm witwout altering the tension of the same.
The diaphragın 14 is stretched by means of adjusting screws over a rectangular
table or frame 15. A carriage formed by two uprights 16 connected by a cross
piece 17 can be caused to move over the said table in a direction parallel to the sides
of the rectangle. The said carriage supports two rollers or cylinders 18 and 19, which
are parallel to the ends of the rectangle and which hold the diaphragm 14 between
them.
A rack 20 operated by a pinion or toothed wheel 21 working over a scale or the
like moves the carriage which causes a movement of the rollers or cylinders
against the diaphragm and consequently a regulation of the amount of its sounding
surface.
•
Springs may be used for moving the carriage backwards and the rack may be

page_text: operated by hand or foot; springs are also used for keeping the rollers close
together.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what I
claim is:
1. In chromatic tymbals or kettle-drums obtaining different notes or sounds,
without altering the tension of the vibrating diaphragm, by varying the extent of
the sounding surface of the said diaphragm substantially as described.
2. A circular chromatic tymbal or kettle-drum, in which variations in the area of
the vibrating surface of its diaphragm are obtained, without altering the tension of
the same, by applying above and below the said diaphragm pairs of like concentric
cylindrical hoops or rings, the two hoops of each pair being simultaneously brought
into contact with the diaphragm by the operation of a pedal, or other mechanical
device substantially as and for the purposes described.
3. A rectangular chromatic tymbal or kettle-drum, in which variations in the area
of the vibrating surface of its diaphragmn are obtained, without altering the tension
of the same, by holding the said diaphragm between two rollers or cylinders arranged
parallel to the ends of the rectangle, which cylinders are capable of being displaced
along a line parallel to the sides of the same substantially as described.
Dated this 1st day of December1005
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.