Improvements in Friction Clutches and Couplings.
Year: 1893

page_text: Date of Application, 22nd Nov., 1893
Complete Specification Left, 22nd Aug., 1894-Accepted, 22nd Sept., 1894
PROVISIONAL SPECIFICATION..
Improvements in Friction Clutches and Couplings.
WILLIAM AMBLER, 26 Elizabeth Street, Bradford Engineer and BENJAMIN
MOUNTAIN of 61, Albion Street, Leeds in the County of York, Manager to The
Bull Dog Friction Clutch Syndicate Limited of 61, Albion Street, Leeds in the
said county, and THE BULL DOG FRICTION CLUTCH SYNDICATE LIMITED of
61, Albion Street, Leeds, do hereby declare the nature of this invention to
be as follows:-
This invention relates to an improved method of constructing friction clutches
or couplings & relates to that class in which a friction ring is expanded and brought
into contact with a friction drum.
Our objects are accomplished in the following manner :-
The expanding ring of the clutch, which is of cast iron or other suitable metal
is constructed similarly to a disc pulley, excepting that the disc is cast with, but
at one edge of the rim and is provided in the ordinary way with a boss for the
purpose of keying or otherwise fixing it on its shaft. The boss is preferably at the
inner side of the disc. The inner surface of the periphery of this friction ring is
turned slightly conical or taper longitudinally whilst the external surface of the
periphery is turned almost to fit the outer shell or case, against which the disc ring
is expanded to cause frictional contact.
The rim and disc of the expanding ring are split radially into a number of parts,
the splits starting from the boss, so as to get the necessary expanding and springing
action.
Within the expanding disc and around the boss of same, we have a circular
block, carrying on its periphery, preferably in lugs, rollers mounted on pins, the
rollers being shaped to the same radius as the inside of the expanding disc ring.
This block is connected by suitable means with a sliding sleeve which is moved in
the ordinary way. Now the action is as follows:-The sliding sleeve being moved
along the shaft it carries with it the circular block with rollers on its. outer
periphery, these rollers are or come into contact with the inner side of the
expanding friction ring which being taper longitudinally gradually expands as the
rollers are forced forward, until frictional contact is made, when the whole revolves
together.
As a modification, our object may be accomplished as follows:-I employ a
friction ring, which is plain at both sides but is made to fit the inside surface of
the friction drum. This ring is cut into two or more pieces, V shaped pieces being
cut out, or in the alternative two right-angle pieces may be cut out & suitable
faces may be attached to the rings or segments by rivets, or other suitable means,
or they may be cast thereto. So as to enter these V grooves, we put rollers which
are turned so that they fit the grooves and a portion of them enters therein. The
action is as follows:-The rollers being connected by suitable means, with the
O sliding sleeve, the same are now moved into gear, which come into contact with and
enter into the V grooves and roll on their pins, but at the same time they open the
groove which pushes the ring or segment against the friction drum and thus
causes frictional contact. The rollers are cut in two from their centres to the
periphery so that packing in the shape of washers may be put between to
5 take-up wear. Within the friction ring we have a block on to which the friction

page_text: ring or segments thereof contract either by themselves or by means of springs
when put out of gear.
Dated this Twenty-first day of November 1893.
COMPLETE SPECIFICATION.
Improvements in Friction Clutches and Couplings.
We, WILLIAM AMBLER, of 26 Elizabeth Street, Bradford, Engineer,
BENJAMIN MOUNTAIN, of 61 Albion Street, Leeds, in the County of York,
Manager, and THE BULL DOG FRICTION CLUTCH SYNDICATE, LIMITED, of
61, Albion Street, Leeds, in the said county, 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 relates to an improved method of constructing friction clutches
or couplings and relates to that class in which a friction ring is expanded and
brought into contact with a friction drum.
Ordinary friction clutches have been objected to on various grounds :—some
being easy to put into action but difficult to release; others, whilst easy to release,
being difficult to put into action; some working well for a short time only, being
badly provided with means for adjustment to meet the inevitable wear and tear;
and others, whilst commanding superior gripping power, having only a small margin
of clearance when disengaged, and on this account giving trouble when supposed
to be released.
The object of our invention is to provide a clutch or coupling capable of being
put in and out of action with ease and certainty, and with as little friction as
possible in the actuating mechanism; capable also of being easily adjusted in its
range of grip as wear and tear require; and having a sufficiently large margin of
release (so as to give no trouble when out of gear) coupled with a powerful grip
evenly distributed over an extensive surface when in action.
Our objects are accomplished as follows:-We employ a friction ring which is
plain at both sides but is made to fit the inside surface of the friction drum. This
ring is cut into two or more pieces, V shaped pieces being cut out, or in the
alternative two right angle pieces may be cut out and suitable faces may be attached
to the rings or segments by rivets, or other suitable means, or they may be cast
thereto; so as to enter these V grooves, we put rollers which are turned so that
they fit the groove and a portion of them enters therein. The action is as follows:-
The rollers being connected by suitable means with the sliding sleeve, the same
are now moved into gear, which come into contact with and enter into the V grooves
and roll on their pins, but at the same time they open the groove which pushes the
ring or segment against the friction drum and thus causes frictional contact. The
rollers are cut in two from their centres to the periphery, so that packing in
the shape of washers may be put between to take up wear. Within the friction
ring we bave a block on to which the friction ring or segments thereof may contract
either by themselves or by means of springs when put out of gear.
In order however to fully explain our invention we have annexed two sheets of
drawings on which
Fig. 1 is a longitudinal elevation, partly in section, and Fig. 2 (Sheet 2) is a
transverse elevation, partly in section, of an apparatus embodying our improvements.
The other figures are explained as we proceed.
We employ a friction ring A which is plain at both sides a, a, and is made to fit

page_text: loosely to the inside surface of the friction drum B, all being machined truly and
accurately, and made, say, preferably, for the sake of cheapness, of cast iron.
This ring is here shown made in two pieces, V shaped portions being cut out, as
at X, in Fig. 3, which is a plan view of the aperture between the ends of the half
rings isolated from their usual surroundings. In some cases right angled pieces
may be cut out, viewing these on the lines a', a', in Fig. 4 (another similar plan
view) and suitable faces a², and a², may be attached to the rings or segments by
rivets or other suitable means, see Figs. 4 & 5, (this latter being a portion of a
transverse section) or these facing pieces a² may be cast along with the other part
of the ring A as in Fig. 2.
So as to enter these ✓ grooves or apertures we mount rollers C which are
carefully turned so that they fit into the groove, and more particularly against the
end faces of the segments A, A. These rollers are so arranged on a continuation
of the sliding sleeve C that their outer side faces, which are slanted to suit the
inclined ends of segments A, enter the V grooves, their diameter, &c., being
arranged to allow this, as in Figs. 1, 2 & 5. The outer edges of the segment faces
are eased off somewhat at the position in which the rollers, when drawn out of
action (see Fig. 3) are beginning to clear themselves, in order to make the final
disengagement of the clutch specially certain. The rollers, which revolve on
pins C³, are carefully cut in two, or rather, are composed each of two rollers placed
side by side so that packing may be placed between, say as washers at C, in order
to restore their faces to their proper working distance from the ends of the
segments A as wear and tear take place, see Figs. 2 & 5.
Within the friction ring is a block D keyed fast to the shaft C³, on which the
friction ring segments A are mounted and by which they are carried round and
enabled to transmit power. This block D is shown in Fig. 2 where the arms D!
insert themselves in corresponding gaps in each segment arranged midway between
their end faces. By this mode of hanging, the segments when out of gear, are left
free to contract themselves inwards and away from the outer drum B, and in this
they are encouraged by the action of springs as shown at E, E, in Fig. 5, or by
springs in tension, as at E in Fig. 2.
The outer drum B has a boss B' by which it is firmly keyed to the shaft B²;
a covering plate B³ (screwed to the drum B) assisting in keeping all internally
arranged parts in their places, and tending to prevent the escape of the lubricant
from the interior.
Recesses D³ are arranged in the block D to allow the mountings on the sleeve
for the actuating rollers to enter and perform their work.
The action of the clutch is as follows:-The actuating rollers C, mounted on or
in connection with the sliding sleeve C (which is moved backward and forward
along the shaft in the usual way), when moved into gear come in contact, whilst
rolling forward, with the end faces of the segments A. The rollers not only
push out and away from the centre the faces with which they come in contact,
which we may call North and South points, but their inclined faces give off at
the same time a side thrust towards points which we may call East and West,
and so the whole of each segment (freely mounted on D¹) receives a well.
distributed outward pressure. This expansion of the segments against the outer
drum brings about frictional contact in the usual manner. On withdrawing the
sleeve the rollers revolve themselves loose and so require only a minimum force for
retiring the expanding ring.
The clutches may be used in various well known ways which need no further
mention, although we prefer to make the outer ring B to be the driver. The
outer ring B or its boss B' may of course have any class of driving gear mounted
thereon.
Instead of the recoil of the inward thrust of the rollers C being taken on the
solid surface of the block D a second roller C may be arranged to roll on the
bed of this block after the manner shown in Fig. 6 which is a half longitudinal
section. Further by inclining the pathway of the inner roller at d an enhanced
.

page_text: outward movement can be passed on to the outer roller. The rollers may be
mounted on independent elastic arms, C & C³, and by supplying a distance piece,
at C, capable of receiving adjusting strips under its base, at C, variations in the
roller positions may easily be arranged. The openings, X, between the ring
segments in this latter arrangement might be more or less parallel, or only slightly
wedged shaped. We mention this more as an example of a variation in the mode
of carrying out the invention than as an improvement on the plan first set out,
which former we prefer.
It is manifest also that a portion only of the circumference of a roller need be
used, in case the whole is too large for the available space.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The hereinbefore described improvements in friction clutches and couplings,
in which rollers with inclined side faces are used for thrusting out and apart
segments of a friction ring against an outer casing or drum; the said rollers
being split for receiving packings for adjusting the said side faces to their work as
wear and tear take place.
2. The combination of an outer case B; segments of a friction ring A, having
inclined end faces; with rollers C, whose side faces act on the said end faces of
the ring segments A; substantially as described and shown, with the object and
for the purpose set forth.
3. The improved friction clutch and coupling arranged, constructed, and operated,
substantially as described and shown.
Dated this 21st day of August 1994
WM. SNOWDON,
9, Old Bank Chambers, Leeds, Yorks, Agent for the Applicants.