Improvements in Friction Clutches.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in Friction Clutches.
We, DAVID HORSBURGH of 10 Oak Street, Chapelfield, Radcliffe, Engineer, and
HARRY DUCKWORTH HALSTEAD, of Orow Oaks, Whitefield, Dyer, both in the
County of Lancaster, do hereby declare the nature of this invention to be as
follows:-
This Invention relates to friction clutches of that type in which an expansible
drum or its equivalent is contained within a collar or pulley attached to or forming
part of the mechanism to be driven. In use, the expansible drum or frictional
surface, which is secured to the shaft, is expanded to engage with the pulley or
the like, and is contracted to effect its disengagement.
A clutch constructed to embody these improvements consists essentially of two
frictional parts each of which has one of its edges formed approximately to a
semi-circle. These two parts are arranged opposite to one another in such a
position that their semi-circular edges practically form a circle and are concentric
to the collar or pulley with which they are to be engaged. They are suitably
flexibly connected to the shaft or to a hub or collar which in turn is secured to
the shaft so as to permit of them moving to a slight extent away from or towards
each other. When the frictional parts are moved away from each other they
engage with the pulley or collar and effect its rotation; when they are moved
towards each other they leave the pulley free and at rest.
The divergent or convergent movement of the two parts may conveniently be
brought about by forming them or providing them at suitable opposite parts
with right and left handed nuts which are fitted with corresponding bolts.
According to the direction of rotation imparted to these bolts the two parts are
forced away from each other or brought together and the clutch is either brought
into operation or is thrown out. The bolts may be rotated or partially rotated,
by fitting them with arms or projections the ends of which are connected to links
joined to a sliding collar on the shaft. As the collar is moved towards or away
from the clutch the arms or projections move up or down and the bolts are
rotated or partially rotated in one direction or the other.
In order to increase the grip of the clutch the semi-circular edges of the moving
parts may be formed with a joint or other suitable flexible part at or about its
centre, or any other convenient part.
Dated this 22nd day of December
D 1000
W. E. HEYS & SON,
Agents for the Applicants.

page_text: Improvements in Friction Clutches.
We, DAVID HORSBURGH of 10 Oak Street, Chapelfield, Radcliffe, Engineer, and
HARRY DUCKWORTH HALSTEAD, of Crow Oaks, Whitefield, Dyer, both in the
County of Lancaster, 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 friction clutches of that type in which an expansible
drum or its equivalent is contained within a collar or pulley attached to or forming
part of the mechanism to be driven. In use, the expansible drum or frictional
surface which is secured to the shaft is expanded to engage with the pulley or
the like and is contracted to effect its disengagement.
I will describe my improvements with reference to the accompanying drawings
in which:
Figure 1 represents a sectional front view and
Figure 2, a transverse section along the line a b.
When
A clutch constructed to embody these improvements consists essentially of two
frictional parts F F₁, each of which has one of its peripheries formed approxi-
mately to a semi-circle. The two parts F F, are arranged together so that their
two peripheries practically form a nearly complete circle concentric with the
collar or pulley with which they are to engage in frictional contact. They are
suitably connected together and with the shaft S, in such a manner as to permit
the two parts to be expanded or moved relatively to the collar or pulley P.
the parts F F, are expanded they engage with the pulley or collar and effect its
rotation by frictional contact, and when they are contracted, they leave the said
pulley free and at rest. We have found that the best and most convenient
method for securing the parts F F, to the shaft $ is by means of the boss B,
keyed upon the shaft. This boss has two radial arms A A, which join the
parts FF, at their respective centres. In other similar types of friction clutch
the frictional contact when the clutch is expanded is found to be applied at one
or two points only, whereas by our construction the contact takes place at the
four points 1, 2, 3, 4. It follows that we thus obtain a higher efficiency.
The divergent and convergent movement of the parts F F, at the points 1-4
may conveniently be brought about by providing at or near each extremity of
each of the parts, nuts having right and left handed screw threads fitted with
corresponding bolts. Thus, as shewn by the Figures, N Nr, nl and nr are
mounted so as to be incapable of rotation, in the blocks D D in which recesses
are formed for their reception and wherein they are secured by the cover
plates E E. The bolts G G are fitted into the nuts before the latter are secured
in their blocks. About the centre of each bolt there is an integral square g
and that part of each bolt on one side of the square has a left hand screw thread gt,
whilst the opposite part of each bolt has a right hand screw thread gr, gr.
According to the direction of rotation imparted to these bolts, the parts F F
at the points 1-4 are expanded or contracted and the clutch is either brought
into operation or thrown out of gear. The necessary movement may be given
to the bolts by means of the links L, L, L, and ₁ are fitted upon the
squares 9 9₁ and the links L, l, each have one end pinned to the first link and
its other end to a lug on the sliding collar H which may have a groove h for the
engagement of the clutch lever. With this or a similar known arrangement, the
movement of the collar H towards or from the clutch will effect the partial
rotation of the bolts and thus, as before described, put the clutch into or out of
Action.

page_text: In order to further increase the grip of the clutch each of the peripheries F F₁
may be formed with a joint or other suitable flexible part, preferably near its
centre, but we have not hitherto found this to be necessary when the form of
construction indicated by the drawings is followed. In no case do we attach
the arms A A₁ to the parts F F, otherwise than at or near their centres as shewn
by Figure 1, as we have found that any departure from this point of attachment
involves a corresponding loss of efficiency."
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what we
claim is :-
A friction clutch constructed substantially as hereinbefore described and as
illustrated by the accompanying drawings.
Dated this 22nd day of September A.D. 1897.
W. E. HEYS & SON,
Agents for the Applicants.