Improvements in Friction-clutch and Brake Apparatus.
Year: 1897

page_text: Date of Application, 1st July, 1897-Accepted, 25th Sept., 1897
COMPLETE SPECIFICATION.
Improvements in Friction-clutch and Brake Apparatus.
I, LEANDRE MÉGY, of 15 Rue des Halles, Paris, France, Civil Engineer do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described an ascertained in and by the following
statement:
This invention relates to friction-clutches of limited power interposed between
a part for transmitting power, such as a pulley or toothed wheel, and a part for
receiving the said power or a part thereof the said clutches establishing or breaking
the connexion between the transmitting part and the receiving part by means of
a spring of circular segmental shape the friction of which is established or is
suppressed between the said transmitting and receiving parts.
The invention has for object by the combination of these clutches properly so
called, with other parts, to impart to the entire arrangement of these kinds of
clutches, a suppleness, a precision and a safety of transmission, which are con-
ditions that it is very important to realise in these kinds of parts or devices, whose
use extends to a large number of apparatus in machinery in general.
The essential part of each of my arrangements of clutches with limitation of
power, consists of my "compound" spring of the form of a circular segment, com-
posed of a strip of steel entirely covered with a frictional strip of leather or other
suitable frictional material, which is attached to the said steel strip.
This spring, which may be an expanding or contracting spring, is fitted either
against the smooth cylindrical wall of a box forming one with the power-trans-
mitting part, or very close to the said wail. At certain points or at any point,
but preferably at the centre, and on the steel strip, there is fixed a tappet which
engages in a notch or groove formed in the periphery of an internal sleeve which
is thereby rendered as it were part of the connecting or detaching spring at the
centre of which is the saiu sleeve, whose extensions are carried in bearings, and
upon whose hub there revolves idly the cylindrical box which forms one with the
transmitting part. The sleeve and the box are connected together or placed into
gear only when the compound" spring bears or is pressed sufficiently against the
wall of the box so as to produce at that place a desired amount of friction.
"
The compound" spring thus arranged is combined with other parts or devices
in the manner hereinafter described so as to impart to the fullest extent to this
kind of clutches, the above mentioned properties. Being always attached to the
central sleeve by means of its tappet, it may be detached from the box or be applied
thereto by acting in various ways at the end or at the middle of its semi-circular
branches.
When the spring is an expanding spring and is then applied against the box,
its ends are connected to the ends of two small rocking levers, on the other ends of
which are arranged rollers between which extends the truncated conical head of
a nut that works on the screw-threaded portion of a shaft, which can rotate but
cannot move longitudinally, and upon the outer end of which is mounted an
operating hand-wheel that enables the said shaft to be turned by hand, whereby
the head of the nut can be caused to enter to a greater or less extent between the

page_text: rollers.
A spring might be interposed between the head of the nut and the rollers
for the purpose of rendering the detachment of the spring gentler and more
gradual.
If the spring is a contracting spring, then its ends, instead of being pulled in
order to contract the spring, must be moved apart in such a manner as to extend
the spring and to press the strip of leather or other frictional material against the
wall of the box when it is desired to throw the aparatus into gear. This is
effected in the same manner by means of the nut-head which also in this case acts
against rollers mounted on the ends of suitably arranged levers, with or without
interposed springs, but preferably with springs in front of or behind the rollers,
in order that the degree of tension or of pressure, may be produced more gradually.
In order to obviate the drawbacks resulting from the friction of the parts, or
from the momentum of the hand-wheel mounted on the shaft that carries the
screw threaded portion on which works the nut with the truncated conical head,
both in the case of an expanding clutch and in that of a contracting clutch, I
prolong to one side the hub of the cylindrical box through the supporting 'bearing,
and I make the end thereof to terininate in the form of a basin on the smooth
cylindrical surface of which I apply a small limiting expanding compound"
spring, provided with the ordinary tappet, which engages in a groove, formed in
the periphery of a disc-shaped shoulder or projection formed on
the screw
threaded central shaft on the end of which the operating hand-wheel is mounted.
This small spring has an amount of expansion which is previously determined and
is such that it serves as a servo-moteur for the nut, ensuring the transmission
of a normal power, but requiring, for varying the amount of the power to be trans-
mitted, the intervention of the hand on the operating hand-wheel. It acts con-
stantly on the nut to return it into its position of rest, as soon as the hand releases
the said operating hand-wheel; if in this case the screw-threads of the nut and of
the screw were arranged inversely, then the nut, instead of producing disengage-
ment, would maintain the engagement, which could only be undone by the, action
of the operating hand-wheel.
66
رو
This rod
Instead of being arranged in the axle of the box, the whole arrangement, con-
stituting a servo-moteur," of the engaging and disengaging nut and its screw
with a hand-wheel, as just described, may be arranged outside on a parallel fixed
axle, the screw rotating about the said axle, under the action of the drum of a
windlass transmitted by means of a pitch-chain, the nut being formed as a sleeve
in the groove of which there engage the vertical limbs of an operating lever, the
said nut rotating on the screw under the action of the said screw or of that of the
hand-wheel, and in the latter case in the reverse direction, in such a manner as to
actuate by means of the said operating lever, a central sliding rod.
would then be provided, with two truncated conical parts, facing each other, the
one acting through levers and rollers upon an expanding engaging spring situated
in the box, and the other acting upon a contracting "head" spring arranged in
a basin and capable of giving or transmitting to the clutch the whole of the desired
power, or of neutralizing the same. In such an arrangement the expanding
spring remains applied," but is only moved when the contracting "head" spring,
which operates it, is engaged-i.e., "applied" or expanded. These parts are com-
bined with the parts for transmitting and receiving power, as also with a governor
with central masses," and with a device having idle pawls which acts as a brake
in one direction of rotation, for the purpose of raising the load, more or less quickly
or retarding it, stopping it or lowering it..
Several clutches, each having a different speed, may, whether they are provided
with expanding or contracting springs be arranged on the same shaft and be
thrown into or out of gear in succession by a common central sliding rod, provided
with as many bosses with truncated conical ends, at suitable distances apart, the
said rod being pushed or drawn from outside by means of an ordinary sliding
sleeve actuated by a forked operating lever.
The improvements that I have made in the clutches which have just been

page_text: described, and which serve to transmit by means of power-limiting springs, and
sliding friction, a. certain mechanical power, aré hereinafter described with
reference to the accompanyin. drawings, wherein
Fig. 1 is a longitudinal section along the axis of a clutch the spring of which
has a preliminary expansion, regulated to a determined expansive tension!
Fig. 2.is a cross section of the same;
I
Fig. 3 is a longitudinal section along the axis of a clutch the arrangements of
which are somewhat similar to those of that of Fig. 1, but which has a spring
with a preliminary contraction designed to act by being expanded or opened out;
Fig. 4 is a cross section;
Fig. 5 is a longitudinal section along the axis of an arrangement of clutch, with
a basin which is formed on an extension continued through one of the bearings,
of the central portion of the box (Figs. 1 and 3) and in which is fitted a small
limiting engaging clutch having an expanding spring;
Fig. 6 is.a cross section of the small limiting clutch above referred to;
Fig. 7 is a horizontal section above the axis of a clutch-box showing the manner
in which a rod sliding laterally on the shaft and ending in a bevelled part, acts
upon levers behind which are leaf-springs that transmit their force to the con-
tracting spring R;
Fig. 8 is a vertical section of a raising windlass" in which the nut and the
screw, by the combination of their reciprocal movements, produce or undo the
engagement:
Figs. 9, 10, 11, and 12 are cross sections according to the lines a b, c d, 'e f
and h; and
"
Fig. 13 is a longitudinal section, showing a group of three clutches, each of
which is to be subjected to a different speed, capable of being successively thrown
into and out of gear by the movement of a common central rod connected to a
sleeve sliding on the shaft and provided with bosses. having "cylindro-conical'
heads these clutches are shown provided with a contracting spring, but they
might equally well be provided with an expanding spring, the two kinds of springs
being capable of being combined together according to the effects or results that
it is desired to produce.
The general arrangement of the clutch or power-limiting brake is constituted in
the following manner:-
A is the part for transmitting the mechanical power for example a grooved
pulley receiving motion through a cable or other means, and rotating in the
direction indicated by the arrow f. The centre or hub of this pulley is hollowed
out in the form of a cylindrical box B which rotates loosely on an internal
sleeve C having hotlow extensions c c and connected to the said box by means of
the "compound" spring R which is in the form of a circular segment composed
of two leaves, one a of steel to which is attached at any point, but preferably at
the centre, a tenon t; the other a¹ of leather forming one with the leaf a, or of
any other material of gentle friction. Upon one of the extensions of the sleeve C,
in which the spring R is maintained by the tappet t, there is keyed the part 1
(which may be a pulley or a toothed wheel) for receiving the power transmitted
by the clutch.
A central shaft G extends through the sleeve C and its extensions, which are
carried in bearings 6 and 61. This shaft, which rotates freely in the centre of the
extensions of the sleeve, but without being capable of moving longitudinally, is
provided with screw-thread G¹ which forms one therewith and on which works a
nut having a truncated conical point. This nut is kept in place by a longi-
'tudinal pind fixed in the internal bore. of the sleeve C. This pin causes the nut F
to be carried along by the rotary motion of the sleeve C, and at the same time
allows the nut to slide longitudinally when caused to do so by the rotary motion
imparted to the central shaft G, either by means of the operating hand-wheel H
mounted on its outer end, or by other means. The screw-thread G¹ the nut F, and
the, hand-wheel H together constitute a
servo-moteur."

page_text: When the "
compound" spring of the clutch is an expanding one (Figs. 1
and 2), the truncated conical point of the nut F, when the latter is pushed along
in consequence of the rotary motion imparted to the hand-wheel H, enters between
the rollers E E¹, which are each mounted on the end of one of the two levers D, D
pivoted at o o, the other ends e e of these levers being attached respectively to the
corresponding ends of the spring R. This entering movement or penetration of
the truncated conical noint of the nut has the result of counter-acting the initial
expansion given to the expanding spring R and of compressing the said spring,
thereby detaching it to a greater or less extent from the cylindrical surface of the
box B, which box is thereby detached to a greater or less extent from the sleeve C,
which moves the said spring R through the tappet t. In order that the action of
the point of the nut F may be more gentle, spring strips may be interposed,
either between the said point and the rollers E E¹, or between the said rollers
and the ends of the spring R, as shown in Fig. 7.
When the engaging spring R has an initial compression (Figs. 3 and 4), then
this spring, in contradistinction to the expanding spring, must, in order to con-
nect the box B and the sleeve C together, be opened out, which is also produced
by means of the nut F when the latter moves forward between two heads f, f¹,
carried by the springs D D' which, on being compressed, act against heads f¹¹ f.
The latter bear elastically against the spring R, open it out, and gradually press -
with more or less force, against the inner surface of the box B, and there produce
friction proportionate to the power to be transmitted, received, or destroyed.
The compression spring may be opened out gradually as in the arrangement
shown in Fig. 7, where the edge of a lateral or central sliding rod ending in a
beveled part enters between two rollers E E¹ arranged at the ends of the levers Q
and acting upon the ends of the compound compression spring R through the
medium of leaf-springs R¹.
In the case of an expansion spring clutch (Figs. 1 and 2), as also in that of a
compression spring clutch (Figs. 3 and 4), the operations can only be effected in
a precise and certain manner so long as the hand-wheel H, which operates the
shaft G provided with the screw G₁ is constantly worked or held by hand. This
hand-wheel, if it were left to itself, might, under the action of the friction of the
parts, or of their inertia, move automatically and thus cause disturbances in 'the
precision of the operations.
In order to obviate this drawback and return in all cases the nut F into its
normal or rest position, when the hand-wheel H is left to itself, I have devised the
arrangement shown in Fig. 5. The hollow hub of the box B forming one with the
pulley A, is prolonged throuch and to the outside of the wearing b, where it ends
in a basin L provided internally with a limiting expansion spring M similar to the
expanding compound spring above described. This spring carries, fixed to its
centre, a tappet which engages in a notch formed in the periphery of the disc-
like internal shoulder O made in one with the shaft G and the screw G' which is
moved by it in its rotary motion. It will be seen that the limiting spring M,
being attached by friction to the basin L, acts constantly through the medium of
the disc O upon the nut F' so as to return the said nut into its normal or rest
position as soon as the operating hand-wheel H is left to itself.
It is only when the hand-wheel is held firmly, that sliding can take place
between the basin L and the spring M.
The result of the operations would be reversed if the thread of the screw G¹
were reversed.
The expansion spring may be advantageously combined with a compression
spring and with the other parts of the clutch and of the general arrangement of
the apparatus, in the case of the windlass, for instance, shown in Figs. 8 to 13.
The nut F¹ is in this case no longer central but outside, is provided with a hand-
wheel H, and works on a screw G" forming one with a wheel which engages
with a pitch-chain u operated by the rotary motion of a drum T¹ and rotates freely
on a fixed axle (1) mounted on the framing of the windlass parallelly to the axis

page_text: of the clutch. This nut is provided with a circular groove in which engage the
two right angled limbs of the fork of the operating lever (2), which are also
engaged at (3) in the circular groove of the sliding central rod (9) in such a
manner as to be capable of causing it to slide longitudinally. This rod is provided
with truncated conical parts (4) and (5), which face each other and which, by the
sliding of the said rod, effect the throwing into and out of gear.
The spring R is an expanding one, and it is combined with the regulating
spring which envelopes the central masses m m, is arranged against a basin
belonging to the sleeve C and forms part, by means of its tappets and the spokes
between which are situated the masses m m, of the box B₁ the hub of which
rotates loosely on the hollow extensions p 1 of the sleeve C¹¹, but carries a
pinion gearing with the wheel y mounted on the axle of the drum T¹ of the
windlass. It is from this axle, through the wheel r, the pitch chain u, and the
wheel mounted on the screw G" that the motion is derived that causes the
rotation of the said screw that tends to move the nut F¹, which has a tendency,
imparted to it by the motion of the hand-wheel H¹, o move in the contrary
direction.
A pawl-mechanisms having sleeping" pawls s¹ s¹, is keyed on the extension pl
of the sleeve C, and according to the direction of the motion of the pawl-plates,
the spring is opened and is applied by the pawls ss, and acts as a stopping or
sliding brake, or it is detached from the box and rotates freely therein.
This being the arrangement and the grooved pulley A" being rotated, then if,
by means of the cone (5), the spring R" is applied to a sufficient degree, the motion
is transmitted by the sleeve C to the box B¹, and consequently to the pinion
which operates, through the wheel y, the drum T on which is wound the rope that
carries the load.
If it is desired to arrest the load, it is sufficient to raise the lever (2) to a
sufficient extent, which has the result of preventing the connexion between the
grooved driving pulley and the disc mounted on the extension p¹ of the sleeve C,
whilst maintaining the connexion between the box B and the spring R¹. By,
however, sufficiently raising the lever (2), this said connexion may be suppressed,
and then the load will descend rapidly. Then if the descent should become more
ranid than is convenient, the governor with movable masses m m, will intervene
and by the action of centrifugal force will render the sleeve C and the box B¹
as one part, with the consequence that rotation of the extension p¹ of the sleeve Cn
would take place in the reverse direction, if this rotary motion did not have the
result of causing by means of the pawls s¹ s¹, the spring 11 to bear with consider-
able force against the internal surface of the fixed box B" which thus acts as
a brake.
In this way, means are provided for raising the load and keeping it suspended,
and of allowing it to descend, even with rapidity. without having to fear that.
this rapidity of descent might exceed a limit that has been previously determined.
Notwithstanding the facility of the above described operations which can be
effected by means of the lever (2), it may be advisable in some cases to impart a
greater degree of precision to the said operations. For this reason I have supple-
mented the direct control effected by the lever (2) by the complementary and yet
independent, control effected by means of the servo-moteur device constituted
by the handwheel H', the screw nut F, and the screw G₁ with long pitch and
forming one part with the wheel v.
The grooved nut F' is connected to the central rod (g) through the bosses on une
end of the fork of the right-angled branch of the lever (2) and the bosses at (3),
but it does not interfere in any way with the operation of the said rod by the
lever (2). On the contrary, the hand-wheel H' controls or operates the said rod.
Thus when the load tends to unwind the drum T¹, the screw G" rotates in one
direction, and the nut F¹, held by the lever (2), rotates in the opposite direction,
so that it remains in the same place. But if the nut is acted upon by means of
the hand-wheel H', then according as the said hand-wheel is turned in one or the

page_text: :
other direction; the nut is caused to move forward as backward, the result being to
raise or depress the lever (2), and consequently to cause the latter to produce the
above described effects.
In a case where there are a series of clutches, each of which is to be subjected to
a particular speed, different from that of the other clutches, I effect the successive
throwing into and out of gear of each of the clutches by means of the device 'sliown
in Fig. 13, in which the central rod T2, provided with as many bosses J with
truncated conical ends, is pushed, as required, by means of the sliding sleeve: K,
in the circular groove of which there are engaged the limbs of the fork of an
engaging lever.
The various clutch-arrangements which have been described are reciprocal
that is to say, the part I may equally well act to transmit power, and the part A
may receive the said power. The expanding springs also, may be compressed by
means of small chains pulling on their ends, and being themselves pulled by the
outer sleeve.
:
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. In a clutch for limiting as desired the power to be transmitted or to be
received by means of an expanding or a compressing spring R arranged in the
cylindrical inner portion of a box B rotating loose on the hollow hub of a sleeve C
whose extensions are carried in bearings, the said sleeve being connected to the
compound spring R by means of a tappet t or t, the combination of the nut
having a truncated conical end, entering either between the rollers E E of 'the'
levers D D, with or without the interposition of leaf-springs, for closing or com-
pressing the spring, or between the heads f, fi, carried by the coiled springs D D
for opening out or expanding the spring ; the longitudinal key d allowing the
nut to turn with the sleeve C and at the same time to slide longitudinally and
the shaft G internally of the sleeve provided with the screw G₁ working in the
nut I, and carrying at its end the operating hand wheel H, substantially as
described and shown in Figs. 1 and 2, and 3 and 4 and for the purpose specified.
2. In a clutch for limiting as desired the power to be transmitted or to be
received by means of an expanding or compressing spring, arranged and combined
as specified in the preceding claim, the combination of the extension P extending
through the bearing of the hub of the box B, and terminating on the outside in
the form of a basin L, against the inner cylindrical surface of which bears an
expanding spring M; and the shoulder or plate in which is made a notch in
which engages a ta nec, substantially as described and shown for the purpose
specified.
3. In clutch-apparatus for limiting as desired the power to be transmitted or to
be received by means of expanding or contracting springs, of the kind indicated
in Claim the combination of the screw G with long pitch turning on the fixed
shaft (1) and forming one with the wheel the nut working on this screw
which is attached to the operating hand-wheel Hand is provided with the circular
groove in which engage the vertical limbs of the lever (2); the central rod (g)
which is caused to slide by the said lever and is furnished with two truncated
conical parts (4) (5) which establish or suppress the connexion between the
springs R and R and their respective boxes; the governor with spring and
"movable central masses m, m; the two other clutch-springs and their corresponding
arrangements and the pawl-mechanisms with soring 11 and "sleeping"
pawls ss, substantially as described and for the purpose of raising, lowering,
stopping more or less rapidly, and generally operating and controlling a load
exactly as required and with perfect safety.
4. In a series of clutches for limiting as desired the power to be transmitted or
to be received, by means of a compound expanding or contracting spring, according
to Claim 1 or Claim 2, in which the several clutches are to have different limiting

page_text: speeds, the bosses J with truncated conical ends, which are equal in number to the
clutch-boxes and are fixed on a rod T₂, which is pushed more or less, according
to the clutch that it is desired to engage or disengage, by means of the sliding
sleeve K, operated by a forked lever, substantially as described and shown and for
the purpose specified.
5. Clutch-apparatus constructed, arranged, and operating substantially as herein-
befor described with reference to and shown in Figs. 1 and 2, Figs. 3 and 4,
l'igs. 5 and 6, and the same as modified according to Fig. 7 of the accompanying
d'awings.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.