Improvements in Rotary Engines.
Year: 1890

page_text: Date of Application, 7th Feb., 1890
Complete Specification Left, 30th Apr.,. 1890-Accepted, 6th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in Rotary Engines.
I, OTTO KOHN, Chief Engineer of the Locomotive Works, at Wiener Neustadt,
near Vienna, in the Austro-Hungarian Empire, do hereby declare the nature of this
invention to be as follows:-
My invention relates to improvements in rotary engines. In carrying it into effect,
I provide not less than four cylinders of a common cross-section and all having their
axes in one plane and bisecting each other at right angles. The piston of any one
cylinder is rigidly connected by its rod to the piston of the opposite cylinder. The
rods are preferably in pairs.
This aggregation of cylinders revolves in the plane containing the axes of the
cylinders about a fixed axis, suitable stuffing boxes and bearings being provided.
The axis of the crank is not coincident with the axis about which the cylinders
revolve but is separated from it by a distance equal to a quarter of the stroke of a
piston. This crank shaft has one throw for each pair of pistons, the crank pins
making with each other angles of twice the size of the angles made by the cylinder
axes with each other. The throws are of a length equal to a quarter of a stroke.
If there are two pairs of cylinders, their axes bisecting each other at right angles,
the throws will be opposite each other; if there are three pairs of cylinders, each
cylinder at an angle of 60° with its neighbours, the three throws will be at angles
of 120° with each other, and so on.
Each piston rod is connected to its respective crank-pin by any usual and convenient
inethod.
The rates of rotation of the crank shaft and the aggregation of cylinders are
as 2 to 1, or in other words the crank shaft makes two revolutions to each one made
by the cylinders.
The cylinders may have their outer ends either open or closed, the valve gear being
modified, or even discarded, accordingly.
When the cylinders have their outer ends, closed, the ports are arranged within the
trunnion-bearings of the aggregated cylinders. In high pressure engines, their
mouths are all in one plane at right angles with the axis of the crank shaft. In
compound engines the ports are arranged in sets for each pair of cylinders of the
same diameter.
There is an elliptical disc at an angle with the shaft within the trunnion bearing
and this disc alternately opens and closes the ports. The angle which it makes with
the shaft is regulated accordingly.
The engine is reversed by turning the disc for nearly half a revolution.
Dated this 6th day of February 1890.
PHILLIPS & LEIGH,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Rotary Engines.
I, OTTO KOHN, Chief Engineer of the Locomotive Works at Wiener Neustadt,
near Vienna, in the Austro-Hungarian Empire 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 relates to improvements in double rotary engines.
In carrying it into effect, I provide not less than two pairs of cylinders of a suitable
cross section. These are rigidly connected with each other, and have, all of them,

page_text: their respective axes in one and the same plane. The two cylinders of any pair are
opposite each other, the axis of one being a linear continuation of that of the other.
Consequently, if there are two pairs.e., four cylinders-they are at right angles
with each other, the axis of one pair bisecting that of the other. If there are three
pairs ie., six cylinders-then they stand at angles of 6° with each other; and so on.
Each cylinder is provided with its own piston, and the two pistons of any pair of
cylinders are rigidly connected together by suitable connecting rods,
Such an aggregation of cylinders as is hereinbefore described is provided with a
pair of hollow trunnions by which it is adapted to revolve in fixed bearings about an
axis at right angles with the plane in which lie the axes of the several cylinders.
The axis of the crank shaft is not coincident with the axis about which the cylinders
revolve. It is separated from it by a distance equal to a quarter of the stroke of a
piston, but is parallel with it.
The crank shaft has, practically, one throw for each pair of pistons, the throws
making with each other angles twice the size of those made by the intersections of
the axes of the respective cylinders. That is to say, in a two-pair cylinder engine,
the cylinder axes being at angles of 90° with each other, the crank pins will be
opposite to each other, while in a three-pair cylinder engine the cylinder axes will be
at angles of 60°, and the crank pins at angles of 120°.
Each pair of piston rods is connected to its crank pin by a suitable sliding block.
The crank shaft makes two revolutions for one of the aggregation of cylinders.
The cylinders may have their outer ends either open or closed.
The arrangement of the ports is decided by considerations of convenience, and may
be modified to meet the circumstances of any particular case.
The steam distribution is controlled by an elliptical disc fixed upon the crank shaft,
and at the proper angle therewith for opening and closing the ports as the engine
revolves.
In order that my invention, and the means by which it is to be carried into practical
effect may be thoroughly understood, I will now describe them in detail, referring in
so doing to the accompanying figures which are to be taken as part of this
Specification and read therewith.
Fig. 1 is a sectional side elevation of a two-pair cylinder engine with closed ends,
omitting the fixed bearings. It is taken on the line A-B of Fig. 2.
Fig. 2 is a vertical section of the same engine. It is taken on the line C-D of
Fig. 1.
E, E are the cylinders of one pair; and F, F¹, the cylinders of the other.
G, G¹ are the hollow trunnions.
The four cylinders and both trunnions are all cast in one piece. The trunnions
revolve in suitable bearings 9, G.
H, H' are the pistons of the pair of cylinders E E'; and I, I' are the pistons of
the other pair F, F.
The pistons of the latter pair are connected by a pair of rigid connecting rods h, h,
and those of the former pair by two pairs i, i, inasmuch as the central position of the
rods h renders it necessary, for obvious reasons, to connect the pistons I, I' along lines
right and left of the central plane in which lie the rods h, h. j, j are sliding cross-
heads by which the piston rods are connected to their respective crank pins.
J is the crank shaft; and j¹,,,, its bearings. The bearings j, j³ serve also as
the glands of the crank shaft stuffing boxes.
Kis the crank pin to which the pistons I, I¹ are connected; and L, L are the two
crank pins (both axially coincident, and therefore practically only one) of the other
pair H, H.
It has been already explained that the axis of the crank shaft is not coincident with
the axis of rotation, being separated therefrom by a distance equal to a quarter of a
piston-stroke, although it is parallel with it. This relationship of position is clearly
illustrated in Fig. 1, in which the circle g' is the bore of a trunnion, and J the crank
shaft.
M is the main steam supply port, and n, n', the subsidiary ports to the

page_text: cylinders F, F¹ respectively. The subsidiary port to the cylinder E is indicated
by the dotted lines o in Fig. 2. The fourth subsidiary port, that to the cylinder E',
does not appear in the figures.
P, is the exhaust common to the four cylinders.
The respective directions of the steam supplies and exhaust are indicated by the
arrows in Fig. 2.
Qis the stationary elliptical dise, by means of which the steam distribution is
effected, as the aggregation of cylinders revolves about it. It is shown as rigidly
connected to the cover R, intermediately through a sleeve r. It is fixed obliquely
upon the sleeve to the extent of being circular in front elevation, and having its
periphery concentric with the axis of the trunnions. The obliquity of the disc, i.e., its
angularity with respect to the vertical plane, is equal to the width of a port from the.
main port M to a cylinder, plus both laps, and the extent to which the port is to be
uncovered. The length of the disc taken in the direction of the axis of rotation is
equal to the length of the port and both inside laps.
The position illustrated in the figures is as follows:-
The piston H has completed its stroke and the exhaust from its cylinder is opening.
The exhaust from the cylinder H' has been completed, and the steam supply port is
opening. The piston I is half way through its return stroke, and its cylinder Fis
exhausting through the port n. The port n' is full open, and the piston F making
its stroke. As the cylinders revolve, carrying those mouths of the four subsidiary
ports nearest to the disc about the latter, each port in turn is opened to supply, cut
off, open to exhaust, and again cut off.
An engine constructed as above described is reversed by turning the disc about its
axis through balf a circle less two laps. For this purpose, the bolt holes in the
cover R are slotted accordingly, or the sleever is made separate from the cover
continued outward through it, and there provided with suitable devices for turning it
through the necessary arc.
It will be seen that the disc above described is the equivalent of the ordinary slide
valve. Consequently, if a multiple expansion engine is to be constructed according to
my invention, one such disc will be provided for each expansion.
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. In a rotary engine, the combination of multiple cylinders arranged in pairs, the
cylinders of each pair axially aligned with and opposite each other, whereby the
cylinders may have their outer ends either open or closed, to rotate by means of
journals projecting at right angles from the plane of rotation; and fixed bearings ;
pairs of pistons connected together and embracing the relative crank pins, which
crank pins form with each other angles twice as large as those made by the axes of
adjacent cylinders; and crank shaft mounted at a distance of a quarter stroke from
the axis of rotation, the crank throws being in length equal to a quarter stroke,
whereby the crank shaft makes two revolutions to one of the set of cylinders; as set
forth.
'
2. In a rotary engine such as is claimed in the foregoing claim and having double
acting closed cylinders, the combination with the set of cylinders of a disc device fast
about the axis of the engine for high pressure engines, and several such oblique discs
for multiple expansion engines, about which dises rotate the mouths of the cylinder
ports for the purpose of governing the supply and exhaust, as set forth.
3. Reversing rotary engines by imparting a partial rotary motion to the disc
claimed in claim 2, as set forth.
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3011
С
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, W.C., Agents for the Applicant..