Improvements in or relating to Friction Clutches for Power Letting.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Friction Clutches for Power Letting.
I, KARL LEVERKUS, of 10 Blumenstrasse, Gohlis, Leipsic in the Empire of
Germany, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention consists in improvements in or relating to "A New or Improved
Friction Clutch for Power Letting" as described in the provisional specification filed
with any patent application No. 21501 of 29th September 1896, which consists in a
friction clutch so arranged, that on inserting a key or crank or similar thing and
turning the same in either direction, the tension of a spring located inside the clutch
will be altered at pleasure, whereby the pressure between the frictional parts of the
clutch is increased or decreased according to the power it is desired to transmit,
while the amount of this power will be indicated by a certain number on a movable
dial, the number appearing through an aperture. The clutch will then transmit not
more than the determined amount of power shown in the said aperture, but will
commence to slide as soon as the required power exceeds the limit. The friction clutch
may also serve as a safety clutch to limit the power transmitted.
I preferably employ a certain well known friction clutch to be described hereinafter
and I adapt it for the purpose mentioned above in the following manner.
The one
clutch half consists in a clutch disk, hereinafter called "C," and in several friction
rings, hereinafter called "H." The clutch disk C is keyed on the one shaft and is
provided on its cylindrical rim at the edge towards the second shaft with an annular
face. The other clutch half consists in a clutch ring, hereinafter called "D," and
in several friction rings, hereinafter called "G." The clutch ring D surrounds the
rim of the clutch disk C leaving an annular cavity, which is closed in at the one
side by the said face of the clutch disk C and at the other side by the face of the
clutch ring D. In this cavity the friction rings H and G are so arranged, that. they
interchange with each other. The clutch ring is provided with feathers engaging
in certain cuts of the friction rings G, so that the latter are prevented from turning
at the clutch ring D and may be shifted only in the direction of the axis. Ín.a
similar manner the clutch disk C is provided with feathers engaging in certain cuts
of the other friction rings H, whereby these are prevented from turning on the
clutch disk C, so that they may equally be shifted only in the direction of the
axis.
The clutch ring D is rigidly connected to a disk, hereinafter called "F." The
latter is made to rest on a sleeve, hereinafter called "I," keyed on the second shaft,
so that the disk F is capable of being shifted in the direction of the axis, while by
feathers it is prevented from turning.
On the second shaft a pressing sleeve, hereinafter called "M," is mounted movable
between the clutch disk C and the sleeve I. It is prevented by feathers from turning
on the second shaft and is threaded on the outside. On the end of the
threaded sleeve M rests concentric with the shaft a circular corrugated spring,
hereinafter called “ K," which at the periphery touches an annular rib at the
clutch disk C. The pressing sleeve M engages in a nut, hereinafter called "N,"

page_text: which is made in one piece with a worm wheel, hereinafter called "O." The
worm wheel O revolves around a part of the sleeve I and works with a worm,
hereinafter called " P," the shaft of which is pivoted in the disk F and has a square
end. The disk F is provided with a rim or mantle reaching beyond the worm shaft,
so that a cavity is thereby formed. In the rim or mantle is an aperture, hereinafter
called "Z," for introducing the nave of a key or crank or other thing, that is put on
the square end of the worm shaft. On turning the key or other thing in one
direction, the worm P will revolve the worm wheel O, whereupon the nut N moves
the pressing sleeve M along the second shaft and presses it on the circular
corrugated spring K. The latter will thereby be strained and its tension will
increase in some proportion to its deflection. The pressure of the circular
corrugated spring K is transmitted on the one side to the clutch disk, C and on the
other side through the pressing sleeve M, the nut N and the disk F to the
clutch ring D. Thereby a certain amount of friction will be produced between
the friction rings G H, the rim face of the clutch disk C and the face of the
clutch ring D.
On the nut N a gear wheel, hereinafter called "R," is keyed on, which works with
another gear wheel, hereinafter called "S." The latter is fastened on the long nave
of a pinion, hereinafter called "T," so that both revolve around a pin. The
pinion Tengages a toothed internal ring, hereinafter called "U," which is connected
to a revolving dial concentric with the rim or mantle of the disk F. The cavity
formed by this rim or mantle is shut off by an end plate having an aperture,
hereinafter called "W." During the revolution of the dial its numbers appear one
after the other through the aperture W. Since the gear wheel R partakes in the
revolution of the worm wheel O, it follows, that on turning the key or other thing
the movable dial will be turned at the same time. When the circular corrugated
spring K is in its natural state, the number 0 of the dial will be visible through the
aperture W. When the spring K is brought into its extreme strained position, the
highest number of the dial will appear through the aperture W. Each position of
the circular corrugated spring K between its natural state and its extreme strained
position corresponds with a certain number of the dial, which will be visible in the
aperture W. All the numbers will, therefore, indicate the largest powers, which the
clutch is capable of transmitting at the fixed number of revolutions in the minute,
while it will commence to slide on the required powers exceeding those powers. The
circular corrugated spring K may also be inserted with a certain tension in
correspondence with the smallest power to be transmitted. In this case the dial may
have numbers, the lowest of which indicates the said power.
The connection between the clutch ring D and the disk F may be done in the
following manner. The clutch ring D is bored out on one side and there the flange
at the periphery of the disk F is fitted, while by feathers it is prevented from
turning. To secure the flange in the clutch ring D, there is in the latter close to
the flange an annular channel, into which a split elastic lock ring (similar to the
common piston rings) is introduced. For the purpose of disconnecting the clutch
ring D from the disk F there are in the clutch ring several holes leading into the
said annular channel. Into these holes pins are placed, which may either remain
loose or be rivetted to the inside of an elastic hoop-like band. When this band is
drawn together, the pins will push the elastic lock ring out of the annular channel,
so that it can be got off.
The number of the friction rings G and H may be increased or decreased according
to the pressure to be exercised for producing the required friction. Instead of the
described friction clutch proper any other friction clutch may be employed, if so
preferred. The aperture Z may either remain open or be closed by a plate or by
some seal lock to prevent any one getting at the inner mechanism. The end plate
is connected with the rim or mantle of the disk F by screws, the heads of which are
protected against surreptitious interference by a cord or a wire being drawn across
them and closed by leads. The toothed internal ring U may be an external one or
it may be a segment only, also it may be in one piece with the dial. The circular.

page_text: corrugated spring K may be provided at its nave with an annular disk for taking up
the wear and tear. In the natural state the circular corrugated spring K may be
symmetrical in relation to its centre plane, so that in the extreme strained position
it is concave with reference to the pressing sleeve M. Or it may be convex with
reference to the pressing sleeve M, so that it requires to be more or less flattened in
order to produce the necessary tension. Or it may be still further pressed and
become concave, ere it attains its maximal tension. The manner of corrugating the
circular spring
may be modified according to the experience to be collected.
-
The friction clutch described so far serves for transmitting the power from the one
shaft to the second one, or vice versa. In case the power is to be transmitted from
a shaft to a gear wheel, a pulley or other millwork, or vice versa, the friction clutch
requires to be adapted. For example the sleeve I may be keyed on the shaft, while
the clutch disk C runs loosely between two set collars and the gear wheel, the pulley
or so on may be keyed on the lengthened nave of the clutch disk C. Or the gear
wheel, pulley and so on inay run direct on the shaft between two loose collars and
carry an annular ring C without a nave etc.
The friction clutch thus described fails to work properly, if the two shafts
connected by it are not exactly in the same straight line, but intersect with each
other, or if the clutch disk C is keyed on its shaft obliquely, because the friction
rings H and G are then liable to be jammed. To obviate this fault and to render
the friction rings independent of the named circumstances, so that they are quite
free to act and their regulated pressure is always maintained, the friction clutch is
altered in the following manner:
The disk F is not made to rest on the sleeve I, but to hang on the edge of the
annular face of the clutch disk C. In the nave of the disk F the nut N is fitted
at its one end, so that it may revolve. The pressing sleeve M is bored out so much,
that an annular space is left between it and the second shaft, while the feathers
on the latter are still able to engage its respective cuts. Since the circular
corrugated spring K and the annular disk at its nave for taking up the wear and
tear rest on the end of the pressing sleeve M and the latter engages in the nut N,
it follows, that all the parts named do not rest on the second shaft at all but in the
nave of the disk F. Thus the circular corrugated spring K with its annular disk, the
pressing sleeve M, the nut N with the worin wheel 0 and the gear wheel R, the
disk F and the clutch ring D with its friction rings G form a self-contained whole
sliding on the face edge of the clutch disk C. The rim or mantle described as
attached to the disk F and reaching beyond the worm shaft and forming a cavity is
now detached from the disk F and connected rigidly with the end plate described as
having an aperture W. This end plate, hereinafter called "X," is inade in one piece
with the sleeve I and thereby changed into a disk keyed on the second shaft.
the edge towards the first shaft the rim or mantle is provided with a cut or several
cuts into which a feather or projecting piece or several of them at the disk F engage.
Thereby the disk X is obliged to partake in the revolution of the clutch ring D and
in that of the second shaft, while the clutch ring D is quite free to shift in the
direction of the axis; also the friction rings G and H are now quite free to act.
At
Where it is so preferred, a series of small balls may be inserted between the face
edge of the clutch disk C and the clutch ring D, so as to reduce the friction between
these two parts and also to diminish the wear and tear. In this case the disk Fis not
made to hang on the face edge of the clutch disk C but is simply suspended to the
clutch ring D.
When it is desired to inspect the interior of the friction clutch, the disk X will
have to be shifted on the second shaft, after its key has been taken off. To facilitate
the replacing of the disk X, the gear wheel S is not fastened on the long nave of the
pinion T, but is mounted movable thereon, while the pin, around which the long
nave revolves, is attached to the disk X and a spiral spring is introduced between the
gear wheel S and the pinion T, whereby the former is pressed against the disk F
and thus kept in engagement with the gear wheel R.
. To secure the nut N, the worm wheel O and the worm P the disk F is provided

page_text: with a seal lock surrounding the end of the worm shaft, while the hole Z in the rim
of the disk X may remain open.
The
To ensure the correctness of the amounts of power shown by the numbers on the
movable dial it is preferable not to oil or lubricate the frictional parts at all, so as to
keep the coefficient of friction constant. Since in this case the frictional parts would
be liable to heating and grinding, I arrange the friction clutch for cooling its
frictional parts by ventilation. This may be done in the following manner.
clutch disk C is made with arms in a similar manner as a common cog wheel, so that
there are openings left between the arms for the air to enter. On the outside of the
clutch disk C a suitable fan or ventilator or blower is mounted for sucking the air and
drawing it in. The cylindrical rim of the clutch disk C and that of the clutch ring D
are provided with openings for letting the air pass in and out. All the friction
rings G and H or some of them are provided on both sides with cuts reaching from
the inner to the outer periphery to allow of the air passing through. The said fan or
ventilator or blower is arranged to be driven from the friction clutch itself by suitable
means, such as friction wheels or pulleys and belts or laces and a counter shaft or
guide rolls.
COMILELE SPECIFICATION.
Improvements in or relating to Friction Clutches for Power Letting.
I, KARL LEVERKUS, late of 10 Blumenstrasse, Gohlis, Leipsic and now of
66 Leibnizstrasse, Charlottenburg in the Empire of Germany, Engineer, 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 consists in improvements in or relating to "A New or Improved
Friction Clutch for Power Letting" as described in the provisional specification filed
with my patent application No. 21501 of 29th September 1896 and in the complete
specification left on 14th June 1897 and accepted on 17th July 1897. The friction
clutch therein described fails to work properly, if the two shafts connected by it are
not exactly in the same straight line, but intersect with each other, or if the clutch
disk C is keyed on its shaft obliquely, because the friction rings H and G are then
liable to be jammed. To obviate this fault and to render the friction rings
independent of the named circumstances, so that they are quite free to act and their
regulated pressure is always maintained, the friction clutch is altered in a manne
to be described hereinafter and shown on the drawing accompanying this my
Complete Specification.
Fig. 1 on the drawing is a side view of the altered or improved friction clutch,
Fig. 2 a longitudinal section of same, Fig. 3 a cross section on the line 8-t in
Fig. 2, the left half of Fig. 4 is a front view taken from the line q- in Fig. 2 and
the right half a cross section on the line u-v in Fig. 2, the left half of Fig. 5 is
a cross section on the line w-x in Fig. 2 and the right half a cross section on the
line y z in Fig. 2. The remaining figures 6 to 11 will be referred to later on.
The alterations of the friction clutch are as follows :-
The disk F is not made to rest on the old sleeve I keyed on the shaft B as shown
in the drawing to the previous complete specification but is suspended to the clutch
ring D.
At the same time a series of small balls Y is inserted between the edge of
the face C¹ of the clutch disk C and the clutch ring D, so as to reduce the friction
between these two parts and also to diminish the wear and tear. In the nave F¹ of

page_text: the disk the nut N is fitted at its one edge, so that it may revolve. The narrower
part of the hole in the pressing sleeve M (in Fig. 2 on the left) is bored out so much,
that an annular space is left between it and the shaft B, while the feather B¹ on the
latter is still able to engage its respective cut (see Fig. 3). Thereby the pressing
sleeve M is rendered independent of the shaft B. Where it is so preferred, the
feather B¹ on the shaft B may be replaced by a suitable projection left at the pressing
sleeve M, the said projection being arranged to engage in the key bed. Since the
circular corrugated spring K and the annular disk L at its nave for taking up the
wear and tear rest on the end of the pressing sleeve M and the latter engages in
the nut N, it follows, that all the parts named do not rest on the shaft B at all but in
the nave of the disk F. Thus the circular corrugated spring K with its annular
disk 1, the pressing sleeve M, the nut N with the worm wheel () and the gear
wheel R, the disk F and the clutch ring D with its friction rings G form a self-
contained whole hanging on the balls Y over the face edge of the clutch disk C.
The old rim or mantle F3 (now X2) described in the previous patent specifications as
attached to the disk F and reaching beyond the worin shaft and forming a cavity is
now detached from the disk F and connected rigidly to the end plate X described in
the said patent specifications as having an aperture W. This end plate X is now
made in one piece with the old sleeve I (now X¹) and thereby changed into a disk X
keyed on the shaft B. At the edge towards the shaft A the rim or mantle X2 of the
disk X is provided with a cut X3 or several cuts into which a feather or projecting
piece F or several of them at the disk F engage. Thereby the disk X is obliged to
partake in the revolution of the clutch ring D and in that of the shaft B, while the
clutch ring D is quite free to shift in the direction of the axis; also the pressure
between the friction rings H and G is now rendered uniform.
When it is desired to inspect the interior of the friction clutch, the disk X will
have to be shifted on the shaft B, after its key has been taken off. To facilitate the
replacing of the disk X, the gear wheel S is not fastened on the long nave T¹ of the
pinion T, but is mounted movable thereon, while the pin T2, around which the long
nave Trevolves, is attached to the disk X and a spiral spring T3 is introduced
between the gear wheel S and the pinion T, whereby the former is pressed against
the disk F and thus kept in engagement with the gear wheel R.
To secure the nut N, the worm wheel O and the worm P the disk F is provided
with a seal lock surrounding the one end of the worm shaft Q, while the hole Z in
the rim X2 of the disk X may remain open. The seal lock is arranged inside the
box F at the disk F and consists in the three pieces Q2, Q³ and Q. The
pieces Q2 and Q are shown in Figs. 6 to 10 on an enlarged scale, Fig. 6 being a
front view of the piece Q, Fig. 7 a longitudinal section of same on the line o-p in
Fig. 6 and Fig. 8 such a section on the line m-n in Fig. 6, while Fig. 9 is a
front view and Fig. 10 a longitudinal section of the piece Q. Fig. 11 illustrates on
the same scale a cross section of the hollow shaft of the key Z taken on a line close
to its bits 72. The piece Q2 is fitted on the square part Q of the worm shaft Q, so
that the latter is turned at the same time, when the former is moved by the key.
The piece Q2 is provided with two projecting parts to allow of the bits 72 of the
key being introduced between them. In a similar manner the piece Q is
provided with two projecting parts for engaging with the key bits. The piece Q
is a ring surrounding the projecting parts of the piece Q2 and is inserted between
the shoulder of the piece Q2 and the face of the piece Q. When the worin shaft Q
is desired to be turned, the key Z¹ is first introduced between the projections of the
piece Q and turned a little, so as to release the ring Q3 and thereby the piece Q²°
with the worm shaft Q. Then the key is moved forward, so that its bits Z2 get into
the annular space between the pieces Q2 and Q', and it is turned a little, until the
bits engage into the projections of the piece Q2, whereupon the key is pushed
forward. After the worm shaft Q has been turned, the key is first withdrawn until
its bits get out of the projections of the piece Q2, then turned a little and withdrawn
until the bits engage the piece Q', whereupon the key is again turned to screw the
piece Q home and thus secure the piece Q through the ring Q3. The number and

page_text: shape of the key bits Z2 may be varied. The seal lock described so far may also be
replaced by any other.
To ensure the correctness of the amounts of power shown by the numbers on the
movable dial V it is preferable not to oil or lubricate the frictional parts at all, so as
to keep the coefficient of friction constant. Since in this case the frictional parts
would be liable to heating and grinding I arrange the friction clutch for cooling its
frictional parts by ventilation in the following manner. The clutch disk C is made
with arms C, so that there are openings left between the arms for the air to enter.
On the outside of the clutch disk C a suitable fan or ventilator C is mounted and
arranged with a rim Cs for a driving lace. The cylindrical rim of the clutch disk C
and that of the clutch ring D are provided with openings C5 and D³ for letting the
air pass through. The friction rings & are provided on both sides with cuts G¹ and G²
reaching from the inner to the outer periphery to allow of the air passing through.
On the rim part C10 enclosing the fan or ventilator Co the pulley C is mounted for
the purpose of driving the fan or ventilator. It may drive through its lace a smaller
pulley on a counter shaft arranged at a convenient distance from the friction clutch.
The motion of the counter shaft is then transmitted through another pulley by
the said driving lace to the rim C of the fan or ventilator C. Thus the latter is
driven at a larger speed than the shaft A, so that it is enabled to suck the air in and
drive the same through the openings of the clutch disk C, the channels between the
friction rings H and G and the openings of the clutch ring D, also through the
channels L between the annular disk L and the flange of the pressing sleeve M. If
the friction clutch slides, the friction rings H and G as well as the annular disk Land
the flange of the pressing sleeve M will become heated through the friction, but as
the air passes through the said channels, it will cool the said frictional parts and carry
off the heat, so that their temperature may be kept at a conveniently low degree and
no grinding can take place. The fan or ventilator C also serves for continually
cleaning the frictional parts by blowing out any chips that may be produced. The
mode of driving the fan or ventilator described above may be modified in replacing
the lace pulleys by belt pulleys or friction wheels or in replacing the counter shaft by
guide rolls or in any other manner. In the drawing the fan or ventilator is shown as
running on two series of small balls C, which are kept apart by a distance piece.
These balls may, however, be omitted. In case the shaft B is the driving one, the
pulley C will require to be mounted on the disk X.
The friction clutch so far described may also serve for transmitting the power from
a shaft to a gear wheel, a pulley or other millwork, or vice versa. In this case it will
require to be adapted in a, similar manner as is described in the previous patent
specifications. The fan or ventilator may then be arranged on the one side of the
gear wheel or so on and the friction clutch on the other side.
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 a friction clutch the arrangement, use and application of a series of balls Y
between the clutch disk C and the clutch ring D or their equivalents for the purpose
of reducing the friction between them when sliding, substantially as shown and
described.
2. In a friction clutch the arrangement, use and application of a fan or ventilator Co
or its equivalent, for the purpose of cooling and cleaning the frictional parts by
driving the air through suitable openings and channels formed therein, substantially
'as shown and described.
3. In a friction clutch the combination with the clutch ring D and the disk For
their equivalents of the nut N, the pressing sleeve M, the annular disk L and the
circular corrugated spring K, all of them forming a self-contained whole hanging on
the balls Y over the clutch disk C, for the purpose of rendering the pressure between
the friction rings H and G uniform, substantially as shown and described.
4. In a friction clutch the combination with the clutch ring D and the disk For
their equivalents of a disk X keyed on the shaft B and arranged to engage the disk F

page_text: by means of one or several feathers or projecting pieces F4 or their equivalents, for
the purpose of rendering the clutch ring D quite free to shift in the direction of the
axis, substantially as shown and described.
5. In a friction clutch the combination with the fan or ventilator C6 having a lace
pulley C or its equivalent, of a lace pulley C or its equivalent placed on the one
clutch member for the purpose of driving the fan or ventilator from the friction
clutch by suitable means at an enlarged speed, substantially as shown and described.
Dated this 9th day of October 1897.
KARL LEVERKUS.