Improvements in Friction Gearing.
Year: 1894

page_text: Date of Application, 19th Jan., 1894
Complete Specification Left, 19th Oct. 1894-Accepted, 8th Dec., 1994
PROVISIONAL SPECIFICATION.
Improvements in Friction Gearing.
I, JOHN SMITH RAWORTH, of 24 Kirkstall Road, Streatham, in the County
of Surrey, Engineer, do hereby declare the nature of this invention to be as
follows:
My invention has reference to a construction of friction gearing adapted for
gearing up or down and specially suitable for use in connection with steam and
water turbines or other fluid pressure motors, as well as electric motors; for the
purpose of reducing the high speed of the motor shaft to a speed sufficiently low
for ordinary mechanical uses.
Friction gearing according to this invention suitable for reducing speed
comprises a small cylindrical pulley fixed on the motor shaft and engaging with
three carrier wheels supported by a face plate keyed or otherwise fixed to the
power shaft. Around the three carrier wheels and engaging with them is placed
a stationary ring made preferably of steel and of such an internal diameter that
it cannot be placed around the three carrier wheels without springing, so that
when placed in position it will firmly grasp the three carrier wheels and force
them into intimate contact with the motor pulley. To enable this to be
done, the bearings or bearing studs of the carrier wheels are not fixed directly
to the face plate, but are carried by swing frames pivotted thereto in such a
manner that the carrier wheels are independently free to move radially, but can
only move circularly with the face plate.
The swing frames are fixed on the back of the face plate and the carrier:
studs project through the said plate, as also do the bosses of the carrier wheels.
Lubricant is introduced through a hole in each stud the arrangement of the
lubricant passages and of the wheel bosses with regard to the face plate being
such that if any lubricant escapes it cannot pass out amongst the friction wheels.
but only behind the face plate.
It will be obvious that the carrier wheels may be carried on arbors instead
of on studs, in which case the face plate may be made double and the arbors
long enough to project outside the double plates.
The outer ring which binds all the wheels together, should be uniform in
cross section so that its springing or bending movement, as the carrier wheels
run round its internal surface, may be equal and symmetrical; it may be made
either solid or laminated.
Any suitable means may be employed to prevent the said ring rotating. Thus
it may be clamped by side clips attached to a fixed frame or support, the clips
being arranged to take hold of the edges of the ring in such a manner as not to
interfere with its radial elasticity. Or it may be clamped by a brake band
embracing the whole or nearly the whole of its outer circumference.
latter arrangement is particularly useful in cases where it is desired that the
power shaft shall be capable of being put in and out of engagement with the
motor shaft.
This
For increasing speed, I employ the same arrangement reversed, the face plate
in this case being driven by the motor.
In all cases where the speed of the face plate is considerable the centrifugal ·
I
.
+

page_text: force of the carrier wheels must be balanced by suitable weights attached to the
swing frames.
Dated this 19th day of January 1894.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Friction Gearing.
I, JOHN SMITH RAWORTH, of 24 Kirkstall Road, Streatham, in the County
of Surrey, 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 :—
My invention has reference to a construction of friction gearing adapted for
gearing up or down and specially suitable for use in connection with high speed
motors such as water turbines or other fluid pressure motors (expressly excluding
steam turbines in respect of which I have applied for a separate Patent of even
date No. 1242) as well as electric motors, for the purpose of reducing the high
speed of the motor shaft to a speed sufficiently low for ordinary mechanical uses.
I will proceed to describe the construction of my improved friction gearing,
for the above purposes, with reference to the accompanying drawings in which,
Fig. 1 shows partly in side elevation and partly in longitudinal section, so much
of the friction gearing with driving and driven shafts as is necessary to enable
the construction thereof to be readily understood.
Fig.
is a face view of one of the swing frames hereinafter more particularly
- referred to.
The friction gearing comprises a small cylindrical pulley a fixed on a motor
or driving shaft a¹ and engaging with three carrier wheels b that are supported
by a face plate c keyed or otherwise fixed to the power or driven shaft d.
Around the three carrier wheels b, of which only one is shown, and engaging
with them, is placed a stationary ring e made preferably of steel and of such
an internal diameter that it cannot be placed around the three carrier wheels
without springing, so that when placed in position it will firmly grasp the three
carrier wheels and force them into intimate contact with the motor pulley a.
To enable this to be done, the bearings or bearing studs f of the carrier wheels
are not fixed directly to the face plate c, but are each carried by a swing
frame g pivoted to the face plate as shown at g' (Fig. 2), the arrangement
being such that the carrier wheels are free to move independently of each
other in a radial direction but can only move in a circular direction with the face
plate.
The swing frames g are mounted on the back of the face plate and the
carrier studs project through openings in the said plate, as also do the
bosses b¹ of the carrier wheels b.
To reduce or balance the centrifugal forces and weights of the carrier wheels,
in cases where the speed of the face plate is considerable, suitable weights g³
may be attached to the swing frames g.
The spring ringe which binds all the wheels 6 together, should be uniform
in cross section so that its springing or bending movement, as the carrier wheels
run round its internal surface, may be equal and symmetrical; it may be made
either solid or laminated. Any suitable means may be employed to prevent
the said ring rotating. Thus it may be clamped by side clips attached to a
fixed frame or support, the clips being arranged to take hold of the edges of
the ring in such a manner as not to interfere with, its radial elasticity. Or it may

page_text: he clamped by a brake band i embracing the whole, or nearly the whole, of its outer
circumference. This latter arrangement is particularly useful in cases where it is
desired that the driven shaft d shall be capable of being easily put in and out of
engagement with the driving shaft a¹.
Lubricant is introduced to the bearing surface of each stud f through a hole f
in the stud, from a lubricant vessel screwed over the outer end of the
corresponding wheel boss, the arrangement of the lubricant passages and of the
other ends 6 of the wheel bosses with regard to the face plate c, being such that if
any lubricant escapes, it cannot pass out amongst the friction wheels but only
behind the face plate through which for this purpose, the ends of the wheel
bosses project as shown. With the arrangement described when the wheels and
pulleys are in close frictional contact and the driving shaft is rotating, the friction
pulley a will cause the carrier wheels & to rotate about their axes and also to roll
against the inner circumference of the stationary ring e with the result that the
face plate and driven shaft will be rotated in the same direction as the driving
shaft but at a lower rate of speed.
It will be obvious that the carrier wheels b may be carried on arbors instead of
studs, in which case the face plate may be made đouble and the arbors long enough
to project outside the double plates.
For rotating the driven shaft at a higher rate of speed than the driving shaft,
I employ the same arrangement but reversed that is to say the face plate c is fixed
upon the driving shaft and the friction pulley a on the driven shaft.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The hereinabove described improved friction gearing comprising two shafts
a friction pulley fixed on one of them (not being a steam turbine shaft) a face plate
or carrier fixed on the other shaft friction wheels mounted on the face plate or
carrier in such a manner that they can move in a radial direction but not in a
circular direction relatively to the said face plate or carrier, and a stationary ring
arranged to tightly surround the friction wheels and press them into close contact
with the friction pulley on one of the two shafts, and in contact with which ring
the said wheels will rotate, substantially as herein before described for the purpose
specified.
2. Speed reduction gearing for transmitting motion from one shaft to another
(excluding a steam turbine shaft), constructed arranged and operating substantially
as herein before described with reference to and shown in the drawings annexed.
Dated this 19th day of October 1894.