Improvements in Friction Clutches or Power Transmitters.
Year: 1893

page_text: Date of Application, 10th Feb., 1893
Complete Specification Left, 9th Nov., 1893-Accepted, 9th Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in Friction Clutches or Power Transmitters.
I, WILLIAM HENRY LINDSAY, of The Shaw Engineering Works, Ashton
Gate, Bristol, Manager, do hereby declare the nature of this invention to be as
follows:-
Cone friction clutches or power transmitters have before been made in which
the outer cone has consisted of a bar of spring metal wound into a conical coil.
When the conical coil so formed has been pressed on to a revolving solid cone
and there has been any resistance to its being carried round with this cone the
friction between the two cones has tended to wind up or increase the number of
turns in the flexible conical coil and so has caused it to contract and firmly grip
the solid cone.
In such clutches as heretofore made the coil has been moved to and fro along
the shaft to engage or disengage it from the solid cone which has been restrained
from endway movement.
According to this invention I make the solid cone movable along but incapable
of turning around the shaft whilst the spring coil is restrained from endway
movement and I enclose the solid and flexible cones within a cylindrical casing
which keeps all dust from settling upon them.
The solid cone I form with a cylindrical prolongation extending from its base-
this prolongation passes out through a closely fitting neck which stands out from
one end of the casing. A groove or collars are also formed on the outer end of
the prolongation by which it and the cone on its end can be shifted to and fro
along the shaft.
The end of the coil which surrounds the smaller end of the solid cone I make
with a lug upon it to engage with the cylindrical casing whilst the other end of
the coil is left free as heretofore.
The cylindrical casing may be part of the boss of a driving or driven wheel
capable of being set loose from the shaft or clutched to it, or may be part of a
boss fast on the end of one shaft whilst the solid cone is carried upon the end of
another shaft in a line with it so that the shafts can be clutched together or
unclutched.
I also form upon the interior of the casing a number of projections which may
be adjustable and which serve to hold the flexible coil entirely out of contact
with the fixed cone when this cone has been drawn back and the clutch is loose
so that at this time there may be no friction and wear taking place between them.
In place also of making the coiled spring cone from a bar of one uniform section
as heretofore I make it from a bar of uniform depth but decreasing in width from
its driving to its free end. The coil being held within the casing by the before
mentioned adjustable projections it cannot jerk back when the cone is pushed into
gear. This obviates the tendency for the spring coil to be shaken loose and dis-
engaged from the fixed coil by any jarring or rattling arising from toothed gearing
on the shafts or from other causes.
The tapering bar may be made up of two or more parallel bars welded together
throughout the first two or three turns of the coil and left unwelded for the
remainder or it might be of a number of bars of decreasing length welded
together so that at one end of the coil the bar would be of a width equal to the
combined width of all the bars and at the opposite end would be of the width of a
single bar.
..
1000

page_text: COMPLETE SPECIFICATION.
Improvements in Friction Clutches or Power Transmitters.
I, WILLIAM HENRY LINDSAY, of The Shaw Engineering Works, Ashton Gate,
Bristol, Manager, 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 :-
Cone friction clutches or power transmitters have before been made in which
the outer cone has consisted of a bar of spring metal wound into a conical coil.
When the conical coil so formed has been pressed on to a revolving solid cone and
there has been any resistance to its being carried round with this cone the friction
between the two cones has tended to wind up or increase the number of turns in
the flexible conical coil and so has caused it to contract and firmly grip the solid
cone.
In such clutches as heretofore made the coil has been moved to and fro along
the shaft to engage or disengage it from the solid cone which has been restrained
from endway movement.
According to this invention I make the solid cone movable along but incapable
of turning around the shaft whilst the spring coil is restrained from endway
movement and I enclose the solid and flexible cones within a cylindrical casing
which keeps all dust from settling upon them.
The solid cone I form with a cylindrical prolongation extending from its base
this prolongation passes out through a closely fitting neck which stands out from
one end of the casing. A groove or collars are also formed on the outer end of
the prolongation by which it and the cone on its end can be shifted to and fro
along the shaft.
The end of the coil which surrounds the smaller end of the solid cone I make
with a lug upon it to engage with the cylindrical casing whilst the other end of
the coil is left free as heretofore.
The cylindrical casing may be part of the boss of a driving or driven wheel
capable of being set loose from the shaft or clutched to it, or may be part of a
boss fast on the end of one shaft whilst the solid cone is carried upon the end of
another shaft in a line with it so that the shafts can be clutched together or
unclutched.
I also form upon the interior of the casing a number of projections which may
be adjustable and which serve to hold the flexible coil entirely out of contact with
the fixed cone when this cone has been drawn back and the clutch is loose so that
at this time there may be no friction and wear taking place between them.
In place also of making the coiled spring cone from a bar of one uniform
section as heretofore I make it from a bar of uniform depth but decreasing in
width from its driving to its free end. The coil being held within the casing by
the before mentioned adjustable projections it cannot jerk back when the cone is
pushed into gear. This obviates the tendency for the spring coil to be shaken
loose and disengaged from the fixed coil by any jarring or rattling arising from
toothed gearing on the shafts or from other causes.
The tapering bar may be made up of two or more parallel bars welded together
throughout the first two or three turns of the coil and left unwelded for the
remainder or it might be of a number of bars of decreasing length welded together
so that at one end of the coil the bar would be of a width equal to the combined
width of all the bars and at the opposite end would be of the width of a single
bar.
The drawing annexed shews a friction clutch or power transmitter constructed as
above described. The clutch is shewn as arranged inside a pulley boss for coupling
it to or setting it free from its shaft.
Figure 1 is a vertical section. Figures 2 and
are cross sections.

page_text: A is the shaft. B is a cone capable of being moved to and fro along the shaft
but restrained by a key or feather from turning around it. C is the conical spring
coil surrounding the cone B and enclosed within the casing D which forms part of
the hub of a pulley E-this casing is capable of revolving freely around the
shaft A. B' is a cylindrical extension of the cone B passing out from the casing D
through a closely fitting neck D₁. B' is a groove formed around the outer end of
this cylindrical extension to facilitate the giving to the cone B its to and fro
endway movement along the shaft A. D² are set screws projecting inwards into
the interior of the casing D and serving to support the spring coil when the cone B
is withdrawn and out of gear with it. In this way the spring coil when out of gear
is kept from coming into contact with the cone B. D³ are lugs on the interior of
the casing between which an extension from the smaller end of the spring coil
enters as shewn at Figures 1 and 2-as will be seen from Figure 1 the interior of
the casing D is also so formed as to restrain the spring coil from endway
movement.
If a screw starting mechanism be used for shifting the cone B endwise this class
of power transmitter can readily be set to release at any given horse power below
its maximum strength-the coil simply slips if more power is required than the
transmitter is set to transmit.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A friction clutch or power transmitter formed with a solid cone capable of
being shifted end wise along a shaft-a conical spring coil surrounding the solid cone
and a casing surrounding the spring coil to which one end of the spring coil is
coupled and which restrains the coil from endway movement the casing itself being
free to turn around the shaft but not to move along it.
2. A friction clutch or power transmitter formed with a solid cone capable of
being shifted end wise along a shaft but not of turning around it, a conical spring
coil surrounding the solid cone, a casing surrounding the spring coil and formed on
its interior to support the coil when the solid cone is out of gear with it such casing
having one end of the spring coil coupled to it and being free to turn around the
shaft but not to move along it.
3. The construction of friction clutches or power transmitters substantially as
herein before described and illustrated in the drawing annexed.
4. A spring cone friction clutch or power transmitter in which the spring cone is
a coil formed from a bar of uniform depth but decreasing in width from its driving
to its free end substantially as described.
5. A spring cone friction clutch or power transmitter in which the spring cone is
a coil formed from two or more parallel bars welded together for the first turn or
turns and left unwelded for the remainder.
6. A spring cone friction clutch or power transmitter in which the spring cone is
a coil formed from a number of bars of decreasing length welded together into one
bar of a width at one end equal to the width of all the bars and at the opposite end
to the width of a lesser number of bars or of a single bar.
Dated this 9th day of November 1893.
W. H. LINDSAY.