Improvements in Rotary Engines.
Year: 1889

page_text: Date of Application, 30th Sept., 1889-Accepted, 30th Aug., 1890
COMPLETE SPECIFICATION.
Improvements in Rotary Engines.
I, WILLIAM NELSON HUTCHINSON, General in Her Majesty's Army, of The Lodge
Silverdale Eastbourne in the County of Sussex 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 :-
One object of the invention is to shew how steam power could be aided with the
greatest assistance derivable from leverage. This is effected by giving to the class
of rotary engines, in which pistons fixed to a central shaft are by steam forced
around an annular passage, pistons of somewhat triangular form having much width
at the part furthest from the central shaft, and with but little width at the part nearest
to it. Another, to provide novel means for making the shutter-valves travel with
great ease and for rapidly opening and reclosing the shutter-valves.
The drawing is a transverse section of an engine very similar to such
is described
in the specification of a former patent granted to me, dated the 9th day of June 1888
No. 8468, on which my present improvements are embodied.
In order to simplify the drawing the details of the piston-arrangements, the friction
wheels for retaining the piston-disc in one undeviating plane, the steam-casing
hot jacket, the constant oil-supply and the like, have been omitted. Much is shewn
merely in single lines.
a is the annular-chamber, which is a fixture. is the steam tight recess, only a
little wider than the thickness of the shutter, into which the shutter retires as the
piston passes the recess. c is the groove (rectangular in transverse section) attached
exteriorly to the annular chamber in which the thin edges of the shutter travel. It is
so deep that the shutter never comes in contact with the outermost sides of the
grooves, (the sides furthest from the main-shaft), nor of the recesses. Thus there is no
jar or concussion.
d is the central revolving shaft to which is fixed the disc e carrying the pistons.
It should be shewn so close to w that the shutter need not pass the slit in
which e revolves. They, the pistons, as is shewn by Fig. 2, are much wider on the
outer part than the inner, so that the larger portion of their area is where the steam
has the greatest leverage. The means by which they work steam-tight in the grooves
is described in the named patent. A thin lip on the sides of their packing-plates
would make them glide over grooves wider than themselves.
9 is the shutter valve seen half way across the annular chamber. It is attached by
a circular bar h (circular for the easy formation of the steam-tight collar x) to the
rod k, which, by bent arms, works on pivots m fixed on both sides of the recess.
9 is a strong stay attached to the recess. At its extremity is a pivot on which works
a two armed crank s. The long arm (r) carries a deeply grooved pulley which
receives the rod r. s is the short arm, acted on by the cam n. The cam is a fixture
to the disc attached to the revolving shaft d. The dotted lines shew the
position of the crank when the shutter is closed. The dotted lines lll the position
when the shutter is within the recess. The cam n by pressing against the short arm s
of the crank makes the long arm press against the rod k. t is the strong arm (within
the steam tight recess) that supports the shutter. It works on the pivot t¹.
v is a
strong disc attached to the annular chamber. To it the lower parts of the recesses
are attached. In its centre there is a circular opening for the shaft d. u u¹are
projecting arms one higher than the other; fixed to the sides of the recess, which
prevent the rod k, (provided with two friction rollers) from swerving from the one

page_text: plane in which it should travel. is an expanding spring abutting against the recess
and the rod k. Transverse brackets embracing the top and two sides of the annular
chamber would enable the sides to resist a steam-pressure that without such aid
might so yield as to increase the width of the slit in which the rim of the pistons-disc
rotates. w is one of the stanchions of the sockets in which shaft d revolves.
Two pistons (Fig. 2) seem best, but were more employed in very large engines, the
horizontally arranged shutters would run on vertically-rotating wheels slightly larger
than the increased thickness given to the shutters. The edge of each would at the
termination of its travel sink into a very slight depression in the groove in order
not to interfere with the close contact of the side of the shutter with the side of the
groove.
The action of the apparatus is as follows.
'
The spring is constantly striving to force the shutter into the recess. When
the shutter is across the annular chamber it is retained in that position for some time
by the pressure of the deepest part of the revolving cam n. As the piston (not seen
in Fig. 1) driven by the steam, gets near the recess, the short arm (s) of the crank is
met by a sudden depression in the cam, when the short arm ceases to force the
longer arm against the rod, and the spring f is enabled to act efficiently against
the rod and push the shutter into the recess. At the instant the piston has passed the
recess even before it has quite passed-a rise in the can (a side of the depression)
presses against the short arm which, (furnished at the place of contact with a friction
roller) overcomes the opposition of the spring and drives back the rod; thus reclosing
the shutter across the chamber. The spring is not stronger than is necessary.
In stationary engines a weight with a wire cord running over a pulley might
be substituted for the spring-three pullies might be required in the lower shutter.
The dotted lines on the shutter shew how it could be held nearer the centre of its
gravity and travel by the rod t (instead of being fixed to the shutter as shown)
being produced, and its flattened upper end entering a hollow passage between the
sides, to be attached to the shutter in its thickest part.
While a shutter is in motion the steam-pressure is equal on both of its sides, and
evidently but little force is required to open and close it. The upper shutter may
almost be said to rock on the pivot t' which supports it, and the lower shutter to hang
as a pendulum from its pivot. There is no friction against the sides of the grooves
in which the rims of the shutter travel, for there is only close contact when the
perfectly flat surface of the rim of the shutter is pressed steam-tight against the
perfectly flat side of the groove.
At the sacrifice of more or less compactness, by increasing the diameter of the
pistons-disc e, leverage is increased and space for using steam expansively, but the
crevice to be kept steam-tight, in which the rim of the disc rotates, is proportionately
lengthened.
It is not necessary that the shaft a should revolve rapidly. The produced flange of
the large cogged wheel attached to the shaft, is cogged on the inner surface and
drives with any required velocity one or more small similarly cogged wheels y.
Their axles o become the useful driving power in machinery. The frame z is a
fixture to the flooring.
Fig. 2 shows one of the two pistons fixed, like recesses at the extremities of a diameter.
Each consists of two plates, bolted centrically together, one being a fixture to the
disc e.
Between the two plates aro two layers of thin packing blocks, forced out-
wards by springs as seen. The junction lines of one layer are covered by the
surface of the other. The diameter of the recesses is vertical, parallel to the cogged
wheel.
The arm t, lengthened and strengthened, would work efficiently, through a steam-
tight collar on a stationary sustaining pivot outside the steam-tight recess, but the
before described arrangement appears preferable, unless, in order to gain leverage,
the pistons-disc (e) is of great diameter compared with the depth of the annular
chamber.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim, is
1. Pistons increasing in width outwards from their inner sides-the sides nearest
to the central shaft.
2. Making the shutter-valves when in movement work on stationary pivots.
3. Rotary engines substantially as described and shewn in the drawings.
Dated this 26th day of September 1889.
W. N. HUTCHINSON,
General.