Improved Friction Device for Transmitting or Arresting Rotary Motion.
Year: 1887

page_text: Date of Application, 18th Nov., 1887
Complete Specification Left, 20th Aug., 1888
Complete Specification Accepted. 18th Feb., 1889
Improved Friction Device for Transmitting or Arresting Rotary
Motion.
We, EDWARD SHAW of Canons Marsh in the city and county of Bristol, engineer,
and GEORGE JOHN HARCOURT, of 5 Albert Villas Clifton, City & County of Bristol,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention is designed to utilize in various ways, as hereinafter more particularly
set forth, the binding and loosing properties appertaining to a metallic coil as applied
either to grip or release a body or bodies about which it is coiled or within which it is
wholly or in part contained.
Und:r one arrangement the coil having an initial grip upon one body and the head,
of the coil being attached to the other body, either body may be moved in one direction
independently, but when moved in the opposite direction carries the other body
with it.
Under another form of application of this invention, one end of the coil is fixed to
The other body
one of two bodies the relative rotation of which is to be controlled.
is gripped by or released from the binding influence of the coil accordingly as the
coil is affected by the application thereto or withdrawal therefrom of a lever or levers
or other device.
In the adaptation of this invention to the purposes of a clutch for enabling a pulley
to rotate with or independently of a shaft on which it is centred the coil is arranged.
around the boss of the pulley which boss is elongated therefor..
Keyed to the shaft and working against one end of the boss is a collar having a
cylindrical chamber formed therein. This chamber extends over the boss, and surrounds
the coil which is, at one end, secured thereto.
•
Rotation of the pulley causes the coil, in the absence of any counteracting influence,
to exert a grip upon the boss, the gripping having begun at the free end of the coil,
which end may conveniently be called the tail, and having extended therefrom
throughout each coil in succession with increased power under the well-known laws
of coil friction.
If, now, the tail of the coil be adequately acted upon by a lever or other device
and the tension thereby relaxed the boss is free and the pulley no longer rotates with
the shaft.

page_text: The same result is obtained if, instead of acting inwards on the boss of the pulley,
as above described, the initial or normal grip of the coil be made to act outwards on
the interior of the chamber of the collar keyed, as aforesaid, on the shaft. In this
case the coil would be fixed at one end to the boss of the pulley and the releasing
device would not press against the tail of the coil but would exert a pull thereat, the
power of the coil depending upon its expansion against the inside of the chamber,
whereas in the arrangement first above described the power depends upon the con-
traction of the coil about the boss of the pulley.
A convenient arrangement for actuating the lever, or its equivalent, by which the
grip exerted by the coil is relaxed, consists of two parellel plates carried upon the
pulley shaft. The plane of one of these is always maintained in the plane of revolution
of the shaft but the plate has no axial motion along it. The plane of the other, whilst
always being kept parallel to the plane of the first, is capable of motion axially along
the shaft and may, at will, be moved, through the medium of a rod, to act upon the
tail of the coil so as to relax the grip thereof, as desired.
Hence the apparatus does not necessarily involve the use of external fulcra or points
of leverage, but is capable of being self contained, as the rod through which the
releasing lever is actuated may be suspended from the shaft or be otherwise conveniently
carried off.
In the adaptation of this invention as self sustaining gear in hoists and the like,
the arrangement is such that the motion of one part is free in one direction but
restrained in the reverse, the restraint being capable of modification or removal.
Under one form of carrying this application into effect, there is carried upon a
shaft, actuated manually or otherwise, a pinion capable of rotating relatively to the
shaft through a definate angle the extent of which is controlled by a stop on the shaft,
or by an equivalent device. To the boss of this pinion is secured one end of the coil
which is arranged around a collar attached to the frame of the hoist. The stop on
the shaft is furnished with an arm which when moved in one direction acts. upon the
free end or tail of the coil.
As the shaft is rotated to raise a load the stop is moved away from the tail of the
coil and engages with the loose key-way of the pinion which latter is thereby carried
round, the coil offering no resistance thereto as the grip exerted on the boss of the
pinion by the coil is then relaxed. If, now, the shaft be set free the load begins to
run down. The motion of the pinion is thus reversed and with it the coil which, in
virtue of the fact that its tail has an initial grip, immediately closes on the aforesaid
collar attached to the frame, and further rotation of the pinion is prevented.
If the shaft be now rotated in the reverse direction to that of the original rotation,
the stop moves freely in the key-way of the pinion until the arm of the stop acts
against the tail of the coil and thus allows the load to be lowered.
By the employment of two sets of controlling mechanism situated at opposite sides
of the pinion, and in which the coils act oppositely, the pinion is, at will, prevented
from rotating by one or the other of the coils while, through the medium of the shaft,
the grip of either coil may be relaxed to permit a load to be raised or lowered in
either direction.
The gripping power of the coil may depend either upon an initial grip of the whole
or of the tail only, or upon pressure exerted externally on the coil by a spring or
other suitable device, and, in the last two cases, the coil may, if desired, be relaxed
by opening the last ring thereof instead by exerting a pressure tangentially against
the end of the tail.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improved Friction Device for Transmitting or Arresting Rotary
Motion.
We, EDWARD SHAW of Canons Marsh, in the city and county of Bristol, engineer,
and GEORGE JOHN HARCOURT, of 5 Albert Villas, Clifton, Bristol, aforesaid,
gentleman, 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 is designed to utilize in various ways, as hereinafter more particularly
set forth, the binding and loosing properties appertaining to a metallic coil as applied
to grip or release at pleasure a body or bodies about which it is coiled or within which
it is wholly or in part contained, and to control its power of grip at any point or stage
of its operation in such wise as, to render self-destruction by breaking impossible, such
control being effected by applying the controlling forces to the ends of the coil and
by limiting the range of motion of the said ends of the coil.
In every application of this invention, whether as regards clutch pullies, clutch
couplings or brakes, the coil having an initial grip upon one body and the head of
the coil being attached to the other body, either body may be moved in one direction
independently, but when moved in the opposite direction carries the other body
with it.
The adaptation of this invention to the purposes of a clutch for enabling a pulley
to rotate with or independently of a shaft on which it is centred is illustrated at
Figs. 1, 2 and 3, Sheet 1, of the accompanying drawings.
The coil A is arranged around the boss of the pulley B which boss is elongated
therefor and is maintained in its proper position on the shaft by the collars E and D
The collar D, keyed to the shaft C, has a cylindrical chamber formed thereon extending
over the boss and surrounding the coil A which is at one end-for convenience termed
the head-secured thereto in the following manner. The head of the coil being
straightened so as to be tangential to the boss B projects through the lug a which is
formed on the coller D. Intervening between a collar b, secured to the head of the coil,
and the lug a, is a spring c. The other end of the coil, which may, for convenience, be
called the tail, is held in the position shown by means of a pin d projecting from the
ond of one of the arms of a hell-crank lever e having its fulcrum fon the collar D.
The other end, g, of the bell-crank lever e is made to bear against the adjustable
sleeve F surrounding the collar D. The latter is provided with a second lug h
placed opposite to the lug a, as shown at Fig. 2, Sheet 1. Against the lug / bears
spring k under compression between it and the bell-crank lever e at i.
By this arrangement, tension is put upon the tail end
produce what we term the initial pressure or grip, the increase of which grip,
of the coil sufficient to

page_text: produced in the act of transmitting power, it is the object of this invention to regulate
automatically. The position of the sleeve F is regulated by a forked lever 1, or
equivalent contrivance, in the usual way. Now, rotation of the pulley in the direction
of the arrow will cause the coil-in the absence of any counteracting influence
through the bell-crank lever and sleeve F-to exert a grip on the boss of the
pulley A, the grip having been started by the initial pressure exerted through the
spring at the free or tail end of the coil and having extended therefrom throughout
each coil in succession with increasing power under the well-known laws of coil
friction.
The position occupied by sleeve F is not arbitrary, but must be so chosen that the
arm g, of the bellcrank shall strike it whenever the resistance against the grip of the
coil exceeds a maximum for which the clutch is designed. This effect is produced
through an extra compression of the buffer spring c, consequent on the undue
resistance, such compression permitting a slight retardation of the coil with the
its clutched pulley-boss, causing the bell-crank to swing back on its fulcrum until
its arm 9 strikes the face of sleeve F as we have stated. The pressure of the
spring k is now neutralized and arme of the bell-crank as if rigidly locked to D, drives
back the tail of the coil, opening and releasing it so long as 'the undue resistance
continues. The proper position of the sleeve F when the clutch is beginning to grip,
may be accurately determined, as the amount of compression of the bufferspring
corresponding to the maximum power to be transmitted is capable of direct
measurement.
If now, the forked lever be brought into play to move the sleeve to the right
until it bears against the bell-crank lever e at g, the pressure of the spring kis
neutralized, the other arm of the lever e is thrown back and the tail of the coil A
uncoiled so as to relax the grip on the boss of the pulley B which will then
continue to revolve without carrying the shaft C round with it.
At Figs. 4, 5 and 6, Sheet 2, is illustrated an alternative method of actuating
the lever e by which the grip exerted by the tail of the coil A is relaxed..
Fitted to the collar D are two sleeves F. F¹ the contact edges of which are
formed with inclines. The sleeves are held from turning round with the collar D, but
the sleeve is capable of moving endwise, and is held in contact by elastic pressure
with the sleeve F¹. A projection o on the sleeve F bears against a cam face n on
the end of a spindle m carried by the sleeve F¹. The turning therefore of the
spindle m will cause the camface to press against the projection of the sleeve F, and
thereby to turn the sleeve, which, travelling over the inclines of the fixed sleeve,
will at the same time, receive an endway motion.
Mounted on an enlarged diameter of the collar D is the bell crank lever for con-
trolling the grip of the coil. The arm g of this lever is brought into contact with the
sleeve F, and it is for the purpose of actuating this lever that the sleeve F receives its
endway motion.
The advantage of this apparatus will be obvious, as it does not involve the use of
external fulcra or points of leverage, such as are shown at Fig. 3, Sheet 1, and Fig. 7,
Sheet 3.
At Figs. 7, 8 and 9, Sheet 3, is represented a clutch coupling for intermittently
driving one shaft from another. In this application of the invention, the boss B being
virtually the first half of the coupling and keyed to the driving shaft C' performs the
same function as the boss of the pulley B hereinbefore described with reference to
Figs. 1, 2 and 3 of the drawings, while the second half of the coupling D, keyed to
the driven shaft C³, corresponds to the chambered collar D in the said Figs. All
the other homologous parts have similar letters of reference and perform corresponding
functions.
Arrangements the same as or similar to those hereinbefore described serve when the
shaft is the driver and the pulley the driven element.
Hitherto the invention has been described as applied to coils in which the gripping
power
is obtained from their contraction. We will now proceed to show, reference
being had to Sheet 4, how it may be adapted when the grip is obtained from the

page_text: is
expansion of the coil used, for instance, as a clutch for coupling two shafts, the coil
being stationary when contracted and connected at its head and tail to the driven
mechanism. The clutched surface is now made to envelope the coil, which must be
shaped to a true cylinder and instead of being in tension when gripping the coil is
now in compression. B, Figs 7, 8, and 9, is the driving part of the clutch-coupling
keyed to shaft C¹ and made to envelope the coil A, which grips it internally, when the
coil is expanded through the action of the controlling gear. D is a sleeve, constituting
the driven part of the clutch-coupling and keyed to shaft C. This sleeve is connected
loosely with the head and adjustably with the tail of the coil A. The controlling
mechanism consists of two concentric rings e and F encircling the sleeve D, and in
convenient proximity to the coil. The inner ring e is notched to receive and to hold
fast the tail of the coil, which is bent for the purpose. A lug g projecting laterally
from this ring e enters a rebate in a ring g' and receives the thrust of a coiled spring k,
contained in that rebate, for producing the initial grip of the coil A. This ring q
secured to sleeper D by a transverse screw mounted in the ring q' and taking into
worm teeth in the periphery of the sleeve D. Upon turning the screw q, the ring qis
made to move on the sleeve D and adjust the position of its rebate relatively to the
y and z the first y
lug g. The outer ring F is furnished with two projecting bosses
for fastening it to any convenient fixture & the second z tapped and provided with a
screwed rod fitted with a handwheel. The cavity of the boss z, adjoining the ring e
holds a plug o, which when forced against the ring e by turning the handwhee!
opposes a resistance to the rotation in the direction of the clutch of the ring e, and
not only neutralizes the pressure of the spring k but also tends to close the coil and
thus to throw the clutch out of gear. The reverse operation of the handwheel will
loosen the plug o, and allow the ring e, to yield to the pressure of spring k. By this
means the requisite gripping by the tail of the coil for putting the clutch into action,
will be effected.
Under another form of application of this invention, one end of the coil is fixed to
one of the two bodies the relative rotation of which is to be controlled. The other .
body is gripped by or released from the binding influence of the coil accordingly as
the coil is affected by the application thereto or withdrawal therefrom of a lever or
levers or other device or devices. Under this head is comprised the adaptation of this
invention to all kinds of brake gear, and the arrangement shown at Figs. 10, 11, 12,
13, 14 and 15; Sheet 5, illustrates its application to what is known as self-sustaining
gear in hoists and lifts.
Under this arrangement the motion of one part is free in one direction, but
restrained in the reverse, the restraint being made capable of modification or
removal.
Under this form of carrying our invention into effect there is carried upon a shaft C¹
(see Fig. 10), a pinion G, capable of rotating relatively to the shaft C₁ through a
definite angle the extent of which is controlled by a stop pin on the shaft, or by an
equivalent device. For this purpose the elongated boss of the pinion G is provided
with a gap or loose key way, shown at Fig. 10, through which the stop-pin, pene-
trates, this stop-pin being by preference a square bar of iron bent in the shape of an L
the vertical leg of which is fixed in the shaft C¹ and the horizontal leg extends over
the gripping coil A as far as the tail thereof. To the boss of the pinion G is secured
the head of the metal coil A which is wound round a collar or cylindrical projection B
concentric with the shaft Cand cast on or attached to the frame of the boist.
In the foregoing examples we have spoken of the initial grip, as obtained by the
use of means external to the coil. In this arrangement, by a modification of the
construction of the coil, the initial grip is secured without the aid of external means.
Thus we make the coil A of tempered steel, and contract it sufficiently at the tail to
produce the initial grip on the brakeboss B and the head of the coil we somewhat
enlarge in its internal diameter.
The pinion G to which the head of the coil is attached gears into a wheel H keyed
to the barrel shaft C².

page_text: Now if the shaft C, be rotated either by means of the handle m, or by a belt or
any other contrivance so as to raise a load attached to the hoist. drum, the stop-pin z
carried by the shaft is moved away from the tail of the coil and engages with the
side of the gap or loose key way in the boss of the pinion G which is thereby carried
round, the coil ceasing to offer any resistance thereto in consequence of the grip
exerted by the coil on the fixed collar B being relaxed, the direction of rotation being
such as to tend to unwind the coil.
If, now, the shaft C¹ be set free, either by releasing the handle m or by throwing
off the bolt or otherwise, the load on the hoist begins to run down reversing the
motion of the pinion, which inasmuch as it carries the head of the coil, which in
virtue of the initial grip of its tail upon the collar B immediately closes upon the
same, completely arrests any further rotation of the pinion and through it arresting
the descent of the load. If the shaft C¹ be rotated in the reverse direction to that of
the original motion, namely that opposite to the "lift," the stop-pin moves freely
in the gap or key-way of the pinion until it presses the tail of the coil thus relaxing
the grip thereof and consequently allowing the load to descend pulling the coil round
with it until the tail moves away from the stop z when the grip is resumed and the
load again restrained.
Hence if it be desired to continue the descent of the load the handle must be turned
accordingly. Thus the apparatus is constantly made to self sustain the load attached
to it and the operator or workman placed in charge of it can never allow it to escape
from under his control.
By employing two sets of controlling mechanism such as last described and attached
to the opposite sides of the pinion G, the coils being thus made to act in opposite
directions, the pinion G may then be made to perform the double duty of lowering
one load while raising another without prejudice to the self sustaining functions of the
apparatus whether the two loads differ in weight or not because the pinion G may thus,
at will, be prevented from rotating by one or the other of the coils, while through the
medium of the shaft C and the two stop-pins z, the grip of either coil may be relaxed
and the loads raised or lowered in either direction.
At Figs. 12, 13, 14 and 15, Sheet 5, is illustrated a modified arrangement of the
application of this invention to a hoist or lift. The difference between this arrange-
ment and that described with reference to Figs. 10 and 11 is due to the fact that the
barrel is keyed to the first shaft (". Hence when the handle m is turned instead of
moving the shaft C₁ within the barrel it moves a casing p to which it is fitted. This
casing surrounds the coil and is mounted loosely on the shaft C¹. To this shaft C¹ is
keyed a collar q which takes the place of the boss of the pinion G. To this collar is
secured the head of the coil A which envelopes the boss B attached to the framing.
The casing p engages loosely with clutch jaws s formed on the collar
9 being other-
wise free to rotate on the shaft C¹. Thus when the handle m is turned so as to raise
the load, the coil A tends to relax and thus moves freely over the boss B, but as soon
as the handle is released, the coil grips the boss and prevents the shaft (1 from
rotating and the load from descending. By reversing the motion of the handle ma
stop r carried by the casing p is brought to bear against the tail of the coil thereby
relaxing its grip and permitting the load to descend as above described.
From the foregoing descriptions it will be seen that the gripping power of the coil
may depend either upon an initial grip of the whole or of the tail of the coil only, or
it may depend upon the pressure exerted externally on the coil by a spring or springs
or other suitable device, the result sought being the automatic control over the
increase of the initial grip when coupling rotating with stationary parts.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
1. The means above described for controlling the grip of gripping coils, whether
used as clutch couplings or as brakes.

page_text: 2. The use of a metallic coil as a clutch or coupling, arranged and operating
substantially as hereinbefore described with reference to Figs. 1, 2 and 3, Sheet 1,
Figs. 4, 6, Sheet 2, Figs. 7, 8 and 9, Sheet 3 and Figs. 7, 8 and 9" Sheet 4 of the
accompanying drawings.
3. The use of a metallic coil as a brake for hoists, lifts and the like, arranged and
operating substantially as herein before described with reference to Figs. 10, 11, 12,
13, 14 and 15, Sheet 5, of the accompanying drawings.
Dated this 18th day of Ananst 1888
J. S. ARNOLD BUCHHOLZ,
Applicants' Agent.