Improvements in Friction Clutches.
Year: 1895

page_text: Date of Application, 12th Mar., 1895-Accepted, 13th Apr., 1895
Improvements in Friction Clutches.
A communication by HARRY WILLARD HILL, of 6, Waverley Avenue, Cleveland,
in the State of Ohio, United States of America, Manufacturer.
1, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool and 6 Bank Street, Man-
chester both in the County of Lancaster, 118 New Street, Birmingham in the
County of Warwick and 31 High Holborn in the County of Middlesex, Civil
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 :-
The invention pertains to the class of friction clutches in which a pair of jaws
are mounted on each clutch arm, and are simultaneously moved in substantially
radial paths toward and from an interposed cylindrical flange, for the purpose of
grasping and releasing the same.
The principal objects of the invention are to simplify the construction, and
cheapen the first cost of clutches of this class; to provide novel operating
mechanism which will occupy very little room on the shaft; to provide cheap and
conveniently operated adjusting mechanism; and to so construct and arrange the
moving parts that they are concealed from view and protected from accidental injury.
The invention relates particularly to construction of the jaws, and of the
mechanism by which they are held upon the clutch arm in the proper relation to
each other; to the mechanism for operating said jaws and to the means for
adjusting their throw.
And the invention consists in the construction and combination of parts herein-
after described and pointed out in the claims.
It is well understood that this class of mechanism may be employed to connect
and disconnect at will either a shaft and a pulley or gear loosely mounted on the
shaft; or two shafts mounted in the same axial line. In the former case the
clutch frame which carries the jaws and their operating mechanism is commonly
keyed to the shaft, and the cylindrical flange which is grasped by the jaws is
secured to the said pulley or gear; in the latter case the clutch frame is secured to
one shaft and the cylindrical flange is supported by arms secured to the other
shaft. The former construction has been illustrated in the drawing, in which,--
Figure 1 is a side view of a four arm clutch;
Figure 2 is a top view of the same,-oue half of the figure being in central
section;
Figure 3 is a side view of the inner side of one clutch arm and one system of
clutch mechanism;
Figure 4 is a sectional view on line 4-4 of Figure 3;
Figure 5 is an inner side view, and
Figure 6 is an edge view of the inner jaw;
Figures 7 and 8 are similar views of the outer jaw; and
Figure 9 is a section through one of the clutch arms on the line 9-9 of Figure 3,
showing one complete clutch system.

page_text: Referring to the parts by letters, A represents a cylindrical flange supported by
arms a which radiate from the hub a' loosely mounted on the shaft F.
Fixed to the shaft F is the clutch frame & having as many arms B, which radiate
from the hub, as it is desired to employ pairs of jaws and associated mechanism.
Each of these arms and the mechanism supported by it, is like every other arm and
its associated mechanism, wherefore a description of one will answer for all.
The arm B consists of two parallel side bars 22 and a connecting web 6ª
preferably integral with the side bars.
The outer jaw C has a shank c which lies between the two side bars ³ ³
whereby it is guided in a substantially radial path. The opposing faces of said
side bars, and the outer edges of the jaw shank, are smoothly finished, whereby
said jaw shank may slide freely.
A radial groove ¹ is formed in the front side of the jaw shank; and a rib d' on
the shank d of the inner jaw fits, and slides in this groove. On the contiguous
faces of the jaw shank c and d are the ribs 2 and respectively; and these
ribs and d² lie in contact with each other when the jaws are held on the
clutch arm in the described relation to each other, thereby reducing the friction
between the two jaws.
Both jaws are held upon the clutch arm by a bolt E, which passes through a
slot in the clutch arm, and a slot in the outer jaw shank, and screws into
a boss d³ on the inner jaw. The head of the bolt bears upon a plate e' which lies
in a recess * in the clutch arm; and as the jaws move, this plate slides upon said
clutch arm.
In all prior constructions of clutches of this class, both of the clutch jaws have
had a bearing upon the clutch arm. In order to provide this bearing in a clutch
in which both jaw shauks lie on the same side of the clutch arm, the side bars have
bad to be made wider than they are in the clutch herein shown and described,
wherefore the prior clutch frames have been, of necessity, heavier than that shown
in the present drawings.
G represents a rocking lever, or rocker, as it is sometimes called, which lies
between the two jaw shanks. It is pivoted to the clutch arm on a pivot parallel to
the shaft F; and, on opposite sides of this pivot, it is pivotally connected with the
jaw shanks. The pivot of said rocker is the inner end of a bolt which passes
loosely through the web of the clutch arm, and screws into the bevelled nut g',
which is thereby drawn against the inner bevelled side of said clutch arm, thereby
fixing the bolt in the clutch arm. The lower end of the shank of the outer
jaw is cut away as shown, so that the said bolt may pass beneath it. One end
of said rocker projects out from between the two jaw shanks and lies just outside
(with reference to the shaft) of the sliding block H. This block is mounted in
a strap on the side of the clutch arm, and is movable in a path substantially
parallel to the path travelled by the jaws. As the block is moved outward, it
rocks the lever G, whereby the jaws are moved in opposite directions toward each
other and the interposed flange. When the block is moved inward, the spring L
which lies between the two jaws forces them apart.
In order to adjust the throw of the jaws so that a given movement of the block
may move the jaws more or less close to each other, an adjustment screw g³ screws
through the end of lever G and bears upon the block H.
The block is moved by a toggle mechanism consisting of the following parts:
A link J which is pivoted at its outer end to said block, and which extends there-
from inward by the side of the shaft F; and a link J' which is pivoted at its inner
end to the frame, and at its outer end to the link J at a point between its ends.
A link J is pivoted to the inner end of the link J, and extends therefrom out
through a slot 6 in the hub of the clutch frame, and it enters a socket n in the
face of the sliding sleeve N, to which sleeve the link is pivotally connected.
From the drawing and the foregoing description, it will be seen that the heads
of the bolts g and E are the only parts which lie outside the clutch frame. Even
the link J2 is entirely hidden from view when the jaws are closed. There is very

page_text: little danger of any accidental damage to the parts; and the clutch presents a very
compact appearance. Because all of the mechanism for operating the jaws lies
behind the clutch frame, between it and the pulley which carries the flange A,
the clutch occupies a very small space comparatively upon the shaft, a desirable
feature much sought for in friction clutches.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. In a friction clutch, in combination, the clutch arm having two parallel sides
and a connecting web, a radially movable outer jaw mounted on said clutch arm
between said sides, a radially movable inner jaw mounted on the outer jaw, said
jaws having, respectively, a radial groove, and a radial rib which lies and moves in
said groove, a bolt which passes loosely through slots in the web of the clutch arm
and the shank of the outer jaw and is rigidly connected with the inner jaw, and
mechanism for moving said jaws simultaneously in opposite directions, substantially
as and for the purpose specified.
2. In a friction clutch, in combination, the clutch arm, having parallel side bars
and a connecting web, the outer jaw mounted on said arm between said side bars
and having a longitudinal groove in its shank, the inner jaw having a rib which
lies and slides in said groove, a screw bolt passing through slots in the web of the
clutch arm and in the outer jaw shank and screwing into the inner jaw, and
mechanism for moving said jaws simultaneously in opposite directions, substantially
as and for the purpose specified.
3. In a friction clutch, in combination, a clutch arm, two radially movable jaws
having shanks which are supported on said clutch arm, a rocking lever which lies
between the two jaw shanks in a plane parallel thereto and is pivoted to the jaw
shanks respectively, and, between said pivots, to the clutch arin, and mechanism
for rocking said lever, substantially as and for the purpose specified.
4. In a friction clutch, in combination, the clutch arm, two radially movable
jaws having shanks which are supported on said clutch arm, a rocking lever which
lies between the jaw shanks in a plane parallel thereto having an arm which projects
from between said shanks, pivots connecting said lever with the clutch arm and
with the two jaw shanks respectively, a sliding block H mounted on the clutch arm,
an adjustment screw passing through the projecting end of said lever and bearing
against said block, and mechanism for actuating said block, substantially as and for
the purpose specified.
5. In a friction clutch, in combination, the clutch, arm, two radially movable
jaws having shanks which are supported on said clutch arm, a rocking lever lying
between said shanks in a plane parallel thereto having an arm which projects
from between said shanks, said lever being pivoted to the clutch arm and on
opposite sides of said pivot with said jaws respectively, a sliding block mounted
on the clutch arm and engaging with said lever and a toggle for operating said
block, substantially as and for the purpose specified.
6. In a friction clutch, in combination, the clutch arm, two radially movable
jaws mounted on the inner side thereof, a rocking lever lying between the jaw
shanks and pivoted to them and to the clutch arın, a sliding block mounted on the
clutch aim, a toggle one link of which is pivoted to the clutch arm at its inner
end and to the other link at its outer end, the other link being pivoted to said
block at its outer end and to a link at its inner end, the last named link which
passes through a slot in the clutch frame, and a sliding sleeve to which said link is
connected, substantially as and for the purpose specified.
7. In a friction clutch, in combination, the clutch arm, two radially movable
aws having shanks which are supported on said clutch arm, a rocking lever
pivoted to the clutch arm ou a pivot which is parallel to the axis of the clutch
which rocker is pivotally connected with the two jaw shanks jon opposite
arm,

page_text: sides of its pivot above named, and mechanism for actuating said lever, substantially
as and for the purpose specified.
Dated this 11th day of March 1805
WM. P. THOMPSON & Co.,
Agents for the Applicant.