Year: 1887

page_text: I THOMAS OWEN ARNFIELD of Globe Iron Works New Mills in the County of
Derby Millwright and Engineer do hereby declare the nature of this invention to be
as follows:-
This invention relates to the construction of what are known as "friction-clutches"
employed for connecting and disconnecting driving pulleys to and from their shafts
in various kinds of machinery.
My improved friction clutch is constructed as follows: The pulley to be connected
or disconnected consists of an outer rim connected by a disc or arms to a central boss
which runs loosely on the shaft. A second boss is keyed fast on the said shaft and
is connected by means of an arm to a friction ring which is placed within the outer
rim of the pulley.
This friction ring is cut, and its two ends are provided with right and left hand
The centre of
screwed nuts, in which works a right and left hand threaded screw.
this screw is provided with a boss made with (say) twelve sides, (more or less) upon
which is fitted a lever, the boss of which is formed to correspond therewith.
This lever is connected by a link to a grooved collar sliding on the shaft, and it
will be evident that as this collar is moved, it causes the link to act on the lever, and
thus rotate the right and left hand threaded screw, which will force the ends of the
ring asunder and cause it to expand tightly into the outer rim of the pulley and thus
connect it firmly to the shaft. If the grooved collar is moved in the reverse direction
the ends of the friction ring are drawn together, and the ring is thus caused to collapse
and release the pulley.
When the outer circumference of the friction ring becomes worn this wear is
compensated for by the following means.
The lever is knocked or forced off the many sided boss in an endwise direction, and
the screw is turned round one flat or more as may be required, and the lever knocked
or forced on again.

page_text: In friction clutches of this kind as hitherto made, when the ring becomes worn, at
that part where the arm, or arms, connects or connect, the ring to the boss, and it was
therefore only near the cut ends that the friction could be brought to bear, but
according to my invention I cast the boss and arm or arms, in one piece, and the ring
in a separate piece, the arm being provided with projections which keep the ring in
place, so that the latter (being free from the boss) is allowed to expand equally in all
directions, and grip to the full extent the inner circumference of the pulley. The
rings will thus wear more equally and will not be so liable to snap as they are when
the ring and boss are cast in one piece as usual.

page_text: An Improved Friction Clutch for Driving Machinery.
I THOMAS OWEN ARNFIELD of Globe Iron Works New Mills in the County of
Derby Millwright and 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 relates to the construction of what are known as "friction-clutches
employed for connecting and disconnecting pulleys or toothed gearing to and from
their shafts in various kinds of machinery.
The nature of my said invention and the manner in which the same is to he per-
formed or carried into practical effect will be readily understood on reference to the
annexed sheet of drawings and the following explanation thereof.
Fig. 1 is a partial longitudinal section of my improved "friction-clutch" and
Fig. 2 is a front elevation thereof drawn partly in section, and with the sliding
sleeve and lever removed.
My improved friction clutch is constructed as follows. The pulley or wheel to be
connected or disconnected consists of an outer rim a connected by a disc a¹ or arms
to a central boss which runs loosely on the shaft c.
A second boss is keyed fast on the said shaft c and is connected by means of an
arm k to a friction ring d which is placed within the outer rim a of the pulley.
This friction ring d is cut so that it can expand and contract and its two ends d¹
are provided with right and left hand screwed nuts d¹¹, in which works a right and
left hand threaded screw d¹¹. The centre of this screw is provided with a boss f
made with, (say) twelve sides (more or less) upon which is fitted a lever g the boss of
which is formed polygonal so as to correspond therewith.
At the middle part of the inner periphery of the expanding ring d is a slot to
receive the driving arm k cast on the boss which is firmly keyed on the shaft c thus
forming a positive yet flexible connection between the expanding ring d and the
shaft c.
9
C,
On the front part of the boss is cast the plate m which being recessed into the
front part of the expanding ring serves to keep it in its proper working position.
The lever is connected by a link h to a grooved collar j sliding on the shaft
and it will be evident that as this collar j is moved in the direction of the arrow it
causes the link to act on the lever g and thus rotate the right and left hand threaded
screw dwhich will force the ends of the ring d asunder and cause it to expand
tightly into the outer rim a of the pulley with its entire circumference in contact, and
thus connect it firmly to the shaft c as shown on the drawing. If the grooved collar j
is moved in the reverse direction the ends d' of the friction ring d are drawn together
and the ring is thus caused to collapse and release the pulley a.
When the outer circumference of the friction ring becomes worn this wear is
compensated for by the following means:
The lever g is knocked or forced off the many sided boss f in an end wise direction,
and the screw d¹¹ is turned round one flat or more as may be required and the lever g
then knocked or forced on again.

page_text: In friction clutches of this kind as hitherto made, when the ring becomes worn, at
that part where the arm (or arms) connects (or connect) the ring to the boss, it was
only near the cut ends that the friction could be brought to bear, but according to
my invention I cast the boss and driving arm k or arms, in one piece, and the ring d
in a separate piece, the arm being provided with lateral projections on a plate m
which keep the ring in place, so that the latter (being free from the boss) is allowed
to expand equally in all directions and grip to the full extent the inner circumference
of the pulley. The rings will thus wear more equally and will not be so liable to
snap as they are when the ring and boss are cast in one piece as usual.
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
First. The general combination and arrangement of parts forming an improved
"friction-clutch substantially as herein before described and illustrated by the
drawings annexed.
Secondly. I claim the construction of a "friction-clutch" having the inner or
expanding ring loose or separate from the driving boss (instead of being cast thereto
or rigidly connected therewith) so that the said ring can grip the outer ring with its
entiro circumference.
Thirdly. I claim the polygonal boss to the double threaded screw and its lever as a
means of compensating for wear substantially as described, and
Fourthly. I claim the side plate cast on the driving boss for the purpose of keeping
the expanding ring in its place.
ليم
1
L Ausw 1000
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicant.