IMPROVEMENTS IN CLUTCHES
Year: 1888

page_text: CISSUS.
I, JOSEPH DAVIS WESTGATE of Worcestor, in the county of Worcester and State
of Massachusetts, United States of America, Machinist, do hereby declare the nature
of my invention for IMPROVEMENTS IN CLUTCHES, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to a clutch by which the rotary motion of a pulley may bo
communicated to a shaft, or vice versa, at tho will of the operator and in which the
clutching mechanism shall partake of some of the essential features of both a friction
and a positivo clutch. In the following description reference is made to the Figures
in the accompanying drawings, which show a clutch embodying my invention and.
in which;
Figure 1 represents a belt pulley upon a short section of a shaft, said pulley and.
shaft being operatively connected by one of my improved clutches, the inclosing shell
forming a cover for the clutching mechanism being shown in central sectional view
in order to more clearly disclose a part of the clutching device.
Figure 2 is a central sectional view of the pulley and clutching mechanism shown
in Figure 1; the section being taken on line X, X, Figure 3, and
Figure 3 is a side view of the belt pulley and clutching mechanism, with the
inclosing shell forming the cover removed.
In the drawings A denotes a portion of the shaft ; B is a disk provided with a
hub B', attached to the shaft A by means of the key a, and a friction flange B³ having
the four equi-distant notches b, b, b, b, three of which are indicated by broken lines
in Figure 3, in which a portion of the disk B is shown as being broken away in order
to disclose one of the notches b. Revolving loosely around the hub B¹ of the disk B
is a belt pulley C having a hub C³, a web and a flanged face C³. The pulley C is

page_text: held between the disk B and a collar C attached to the shaft A. D is a flange
extending from the web of the pulley over the friction flange B² and having an
opening or slot D', Figure 3. Around the friction flange B³ I place a friction
strap E, preferably made of cast metal and having at one end à lug c turned
outwardly.
The opposite end of the strap E is made to overlap the lug c and is provided with
a lugd turned inwardly, and in the space inclosed between the overlapping ends of
the friction strap and between the lugs c, d, I place a lozenge shaped bar indicated by
broken lines at F, Figure 3 and attached to, or formed integrally with the outer end
of the bar F, is a lever F, slightly bent and extending over the shaft A as shown in
Figures 1 and 3. G is an eccentric capable of sliding upon the shaft A, but having
a spline connection with the shaft and having a hub G with an annular groove e to
receive a shipping device in the shape of.a forked lover or other shipping device now
in use in other forms of clutching devices.
To the friction strap E is attached an elastic strap HI (in the present instance the
strap His shown as formed integrally with the strap E) extending nearly around
the flanged disk B and having at its free end the neck Hand enlarged head H², the
neck H being oblique to a radial line extending from the head H to the center of
the shaft A. At tho central section of the elastic strap H is a projecting tooth H³
with the sides f, g, which inclose the point of the tooth, forming an obtuso angle
fitting the notches b, b, b, b, in the friction flange B³. Jis a cover seated upon the
edge of the flange C forming the face of the pulley and having a concentric opening J¹
fitting the hub G' of the eccentric G. The cover J is attached to the web of the
pulley by means of screws J² passing through the holes J³ in the web C' and entering
screw threaded holes in the bosses J upon the inside of the cover J. Whenever the
belt pulley C is rotated in the direction of the arrow 1, Figure 1, the elastic strap H,
friction strap E and actuating lever F¹ with its lozenge shaped bar F will be carried
around the flanged disk B, causing. the inner surface of the friction strap E to slido
over the outer surface of the friction flange B³. If, during the rotation of the
pulley C and connected friction mechanism, the eccentric G is made to slide along
the shaft A in the direction of the arrow 2, Figure 2, beneath the free end of the
lever F, the end of the lever F¹ will be carried around the eccentric G and upon
the side of the greatest radius, causing the end of the lever F¹ to be raised away from
the shaft A, and rotating the lozenge shaped bar F between the lugs c, d. The acute
angled corners 3, 4, of the bar F rest, in the normal position of the bar, against the
inner sides of the lugs e and d, and as the bar F is rotated the edges 3, 4 will press
the lugs c, d, apart and cause the friction strap E to be compressed upon the outer
surface of the friction flange B2 and, by the frictional resistance between the inner
surface of the strap E and the outer surface of the flange B2, to cause the rotation of
the pulley C to be imparted to the shaft A through the flange B2 and disk B. In
case the frictional resistance between the inner surface of the strap E and the outer
surface of the flange 132 is not sufficient to transmit the power applied to the pulley C
so as to overcome the resistance of the shaft A and its connected machinery, the pulley.
will still move around the flange B2, but as the rotation of the friction strap E and
connected strap H is checked by the friction of tho strap E upon the outor surface of
the flange B², the motion of the pulley C will cause the end H of the flange D to
slide upon the oblique neck H' and carry the free end of the clastic strap H inward
toward the disk B, carrying the tooth H³ into one of the notches b, in the flange B2,
in case there is any movement of the friction strap E around the flange B. When-
over the eccentric & is removed from beneath the end of the bent lever F1 the friction
strap is allowed to release its hold upon the surface of the flange B² and the elastic
strap H will assume its normal position as shown in Figure 3, withdrawing the tooth H
from the notch in the flange B2. The first action of the clutching mechanism is
to attach the strap E to the outer surface of the flange B2 by means of the friction
between them, and the second action is to cause the continued motion, if there is any,
to carry the tooth H³ into one of the notches b in the flange B' and thereby effect a
positive engagement between the pulley and the flanged disk B, which being attached

page_text: to the shaft A will cause the rotation of the pulley to be imparted to the shaft A.
The eccentric G may be moved along the shaft A by means of any of the known
shipping devices applied to the annular groove in the hub G', or the hub G¹ may be
made hollow as shown in Figure 2, inclosing an annular chamber K around the
shaft A, in which I place the spiral spring K with one ond resting against the end
wall of the chamber and the other end resting against the collar Kattached to the
shaft A, and the shipping mechanism applied to the groove e in the hub G¹ is then.
used to withdraw the eccentric from beneath the end of the lever F' and to hold it in
the position as shown in Figure 2.
Whenever the eccentric is released the action of the spiral spring serves to press
the eccentric toward the end of the lever F' and as soon as the side of the eccontric
having the smallest radius is brought opposite the end of the lever the force of the
spring is sufficient to carry the eccentric under the end of the lever, raising it and
causing a partial rotation of the lozengo shaped bar F, compressing the friction strap
upon the flange B* in the manner already described. When the spiral spring is used
the shipper must of course be locked in position to hold the spring from carrying the
sliding eccentric beneath the end of the bent arin or lover F. The side of the
eccentric next the lever F is bovelled at G2 in order to cause it to pass readily beneath
the end of the lever F1. The "throw" of the eccentric G, should be greater than is
required to raise the end of the lever F¹, in order to allow for any lost motion or wear
of the operating parts.
Aside from the action of the end H of the flange D upon the oblique neck H³ of
the elastic strap H to carry it in toward the flangod disk B, the strain of the pulley C
upon the elastic strap H in communicating the rotary motion of the pulley C to the
shaft A will tend to draw the tooth H³ closer to the flange B' and into one of the
notches b.
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. In a clutch, the combination with a shaft and a disk attached to said shaft
and having a flange provided with notches, of a revolving pulley provided with a
slotted flange and having a concentric motion around the axis of said shaft, a friction
strap having connected operative mechanism, substantially as described, by which it
is compressed around the outer surface of said flange baving notches, an elastic strap
integrally attached at one end to said friction strap and having at its free end an
oblique neck held in the slotted flange of said pulley, and having a tooth at the central
section of said elastic strap and upon its inner surface, said tooth being adapted to
engage the notches on said notched flange, substantially as described.
Second. In a clutch, the combination with a shaft, of a disk attached to said shaft
and having a flange, a friction strap capable of being compressed on said flango, an
clastic strap integrally attached to said friction strap at one end and with the othor
end connected with the revolving pulley, and a revolving pulloy whose motion is
imparted to said flange and disk through said elastic strap and said friction strap,
substantially as described.
Third. In a clutch, the combination with an elastic friction strap having connected
actuating mechanism, substantially as described, embodying a lever extending over
the shaft, of an eccentric rotated by the shaft and capable of sliding thereon,
substantially as described.
Fourth. In a clutch, the combination with a lever extending over the shaft and
having connected clutching devices, substantially as described, whereby the rotary
motion of the pulley is imparted to the shaft or vice versa, of an eccentric capable of
sliding on the shaft but held from rotating theroon, by which said lever is raised
radially from the shaft and the clutching devices operated thereby, substantially as
described.
Fifth. In a clutch, the combination with clutching devices, substantially as described,
whereby the rotation of a pulley is imparted to a shaft, or vice versa, of a lever

page_text: extending over the shaft and operatively connected with said clutching devices,
mechanism by which said lever is actuated through a sliding motion on the shaft and a
spring applied to said actuating mechanism, whereby it is moved along the shaft and
beneath said lever, substantially as described.
Sixth. In a clutch, the combination with mechanism by which a rotating pulley is
made to engage its shaft, or mice versa, of an eccentric capable of sliding on the shaft
but held from turning thereon, said eccentric having a bevelled edge and connected
devices, substantially as described, whereby it is moved on the shaft, substantially
as described.