Improvements in Friction Clutches for Pulleys.
Year: 1892

page_text: Date of Application, 12th Apr., 1892
Complete Specification Left, 12th Jan., 1893-Accepted, 25th Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements in Friction Clutches for Pulleys.
1, WILLIAM WALTER OLDFIELD, of Kerr Street, Mile End, Glasgow, Belt
Maker, do hereby declare the nature of this invention to be as follows:-
This invention relates to friction pulleys and it has for its object to improve and
simplify their construction.
In carrying out my invention, I make the pulley with an inner raised part or
rim, which is concentric with the circumference of the pulley. Fitted on to the
shaft, which may pass loosely through the pulley, is a disc, preferably flanged.
around the circumference. This disc can pass into one side of the pulley. Secured
to the disc, is a split, spring ring or band, or its equivalent, which passes round
the inner rim of the pulley. The split ring has, at its ends, two projecting fingers:
or lugs, which pass through a hole in the disc and are gripped or held by the short
arms of two levers, which are suitably fulcrumed to the disc. The long arms of the
levers have, preferably, fitted in or to them, adjusting screws or their equivalent..
Fitted loosely on the shaft, is a clutch, having a wedge-shaped projection. The
clutch can be travelled back and forward on the shaft, by any suitable and well-
known mechanism.
The action of the friction pulley is, as follows:-
When the clutch is slid along the shaft, the wedge-shaped projection enters
between the screws, and forces them apart, so opening out the lower ends of the
levers, and consequently bringing together their upper ends. The bringing together
of the upper ends of the levers, causes them to compress together the projections on
the split ring or band, which is thereby tightened around the inner raised part or
rim of the pulley, and causes said pulley, by the friction between the inner rim
and the split ring, to revolve with the shaft. Immediately the clutch is withdrawn,.
the spring, or split ring, opens up of its own accord, and releases its frictional grip
on the inner rim of said pulley, so that the latter is freed.
Dated this 11th day of April 1892.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.
COMPLETE SPECIFICATION.
Improvements in Friction Clutches for Pulleys.
WILLIAM WALTER Oldfield, of the firm of J. Oldfield & Sons, Mile-end
Leather Works Kerr Street, Glasgow. in the County of Lanark North Britain 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 which relates to friction clutches for pulleys, has for its object
to improve and simplify their construction.
In carrying out my invention, I make the pulley with an inner raised part or rim
which is concentric with the circumference of the pulley. Fitted on to the shaft,
which may pass loosely through the pulley, on a disc preferably flanged around
the circumference. This disc can pass into one side of the pulley. Secured to the
disc is a split spring ring or band or its equivalent which passes round the inner
rim of the pulley. The split ring has at its ends two projecting fingers or lugs
which pass through a hole in the disc, and are gripped or held by the short arms
of two levers which are fulcrumed to the disc.

page_text: .
The long arms of the levers have preferably fitted in or to them adjusting screws
or their equivalent. Fitted loosely on the shaft is a clutch having a wedge-shaped
projection. The clutch can be travelled back and forward on the shaft by any
well known & suitable mechanism. In order that my said invention may be fully
understood and readily carried into effect I will proceed to describe. the drawings
hereunto annexed.
Fig. 1 is a part plan, and part horizontal section, illustrating the friction clutch
in action with a pulley as made in accordance with and constituting my invention..
Fig. 2 is a front elevation of the hollow disc clutch.
Fig. 3 is a similar view to Fig. 2, showing the hollow side of the disc, and
Figure 4 is a detached plan of the wedge all hereinafter more fully described.
The belt pulley A, with its inner annular shell or flanged portion B, is mounted
loosely on the shaft C. The said inner annular shaft B though shown rigidly cast
one with the pulley A, may be constructed as a separate piece and applied to
existing pulley's by clamping the outer cheek thereof to the arms of such pulleys.
The hollow stationary disc D which may be fixed to the shaft C, by the well
known means of key & groove, or by tangent screws, is so located relatively with
the inner annular shell B, that it revolves freely, when the clutch is not in gear,
round the circumference of the flange B' of the said annular shell B.
The
Frictional contact of the clutch D is obtained by means of a split ring E, which
is fixed concentrically within the said hollow disc D, by any suitable means.
free ends F & G of the said ring E are provided each with a projection H and I
which pass through a radial slot J. The normal tendency of the split ring E,
with the free ends, F & G is to become expanded, such tendency is controlled and
resisted by the short ends K & L of the levers M & N. which engage the
projections H & I by means of a wedge T hereafter fully described. The said
levers M & N are of a curved configuration as seen in Fig. 2, and are pivoted
at O&P to the outer cheek of the hollow disc D. The long ends of the said
levers M & N near to the extremities thereof are provided with vertical adjusting
screws Q&R having rounded heads as seen. Between the heads of the said
adjusting screws Q & R & the gap S formed in the disc D travels the wedge or
other uniform projection T in the horizontal plane. Backward & forward motion
is imparted to the said wedge T by means of the loose sleeve or clutch U, operated
by levers as will be understood. The shape or configuration of the wedge T is
seen more particularly in Fig. 4. A maximum degree of tenacity or grip of the
clutch is obtained when the wedge T is thrust between the adjusting screws Q & R
as aforesaid, to such extent that the convex points t thereof have got behind the
before mentioned screws Q & R. When the clutch U is slid along the shaft the
wedge shaped projection T enters between the screws Q & R and forces them
apart and consequently bringing together the ends K & L of the levers M & N.
The bringing together of these ends of the levers causes them to compress together
the projections H & I on the split ring or band E, which is thereby tightened
around the inner raised part or rim B₁ of the pulley A, and causes said pulley by
the friction between the inner rim & the split ring E, to revolve with the shaft C.
Immediately the clutch is withdrawn the spring or split ring opens up of its own
accord and releases its frictioned grip on the inner rim of said pulley, so that the
latter is freed.
Having now particularly described and ascertained the nature of ny said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
First. In friction clutches for pulleys, the levers M & N curved concentrically
to the axis of the shaft C pivoted near their shorter ends each independently of the
other to the surface of the hollow disc D, and actuated by the wedge T substan-
tially as shewn and described for the purposes set forth.
Second. In friction clutches for pulleys, constructing the pulleys with, or
clamping thereto, an inner shell or flanged periphery, whereby a frictional surface

page_text: is provided on the exterior surface thereof, for action thereupon by the split
friction ring of the clutch, substantially as described & shewn and for the purposes
set forth.
Third. In friction clutches for pulleys, the arrangement and combination of parts
consisting of the hollow disc D, the levers M and N, the split friction ring E, and
the wedge T, substantially as shewn and described and for the purposes set forth.
Fourth. The improved friction clutch constructed, arranged, and operating as
hereinbefore described and illustrated by the accompanying drawings.
Dated at Glasgow the 25th day of November 1892.
D. DRYSDALE AUSTIN,
45, Hope Street, Glasgow, Applicant's Agent.