Improvements in or relating to Steam Turbines.
Year: 1894

page_text: Date of Application, 19th Jan., 1891
Complete Specification Left, 2nd Oct., 1894-Accepted, 3rd Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in or relating to Steam Turbines.
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:-
This invention of improvements in or relating to steam turbines, has for object
to enable the speed of such turbines, which is very great, to be easily reduced to an
extent sufficiently low for ordinary mechanical uses without the employment for
this purpose of electric dynamos and motors. To this end I combine with the
turbine shaft and the shaft or other rotary body to be driven therefrom, and
hereinafter referred to as the power shaft, a novel arrangement of friction gearing.
This friction gearing comprises a small cylindrical pulley fixed on the turbine
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
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. This latter
arrangement is particularly useful in cases where it is desired that the power shaft
shall be capable of being easily put in and out of engagement with the motor
shaft.
I propose to reduce or balance the centrifugal forces and weights of the carrier
pulley by suitable weights attached to the swing frames.
Dated this 19th day of January 1894.

page_text: Improvements in or relating to Steam Turbines.
1, 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 :-
This invention of improvements in or relating to steam turbines, has for object to
enable the speed of such turbines, which is very great, to be easily reduced to an
extent sufficiently low for ordinary mechanical uses without the employment for
this purpose of electric dynamos and motors. To this end I combine with the
turbine shaft and the shaft or other rotary body to be driven therefrom, and
bereinafter referred to as the power shaft, a novel arrangement of friction gearing,
as I will now proceed to explain by reference to the accompanying drawings
wherein
Fig. 1 shows partly in side elevation and partly in longitudinal section, so much
of the friction gearing with turbine and power shafts as is necessary to enable the
construction thereof to be readily understood.
Fig. 2 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 the turbine
shaft at and engaging with three carrier wheels b that are supported by a face
plate c keyed or otherwise fixed to the power 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
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 9 are mounted on the back of the face plate e and the carrier
studs project through openings c' 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,
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 meaus 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 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
power shaft a shall be capable of being easily put in and out of engagement with
the motor shaft d.
Lubricant is introduced to the bearing surface of each stud 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 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

page_text: only behind the face plate through which for this purpose, the ends 61 of the
wheel bosses project as shown. With the arrangement described when the wheels
and pulleys are in close frictional contact and the turbine shaft is rotating, the
friction pulley a will cause the carrier wheels b 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 power shaft will be rotated in the same direction
as the turbine 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 double and the arbors long enough
to project outside the double plates.
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 combination with the main driving shaft of a steam turbine and the
power shaft to which the motion of the turbine shaft is to be transmitted, of
friction gearing comprising a friction pulley fixed on the turbine shaft, a face
plate or carrier fixed on the power 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 the turbine shaft, and in contact
with which the said wheels will rotate, substantially as hereinbefore described
for the purpose specified.
2. Speed reduction gearing for steam turbines constructed arranged and operating
substantially as hereinbefore described with reference to and shown in the drawings
annexed.