improvements in Rotary Engines.
Year: 1895

page_text: Date of Application, 3rd Dec., 1895-Accepted, 4th Jan., 1896
improvements in Rotary Engines.
We, CARL ALRIK HULT, and OSCAR WALFRID HULT, both of 48, Flem-
minggatan, Stockholm, in the Kingdom of Sweden, Engineers, 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 :-
Our invention relates to engines or motors which are driven by steam or other
fluid and in which a piston (or several pistons) rotates within a casing (or several
casings). The invention has for object to reduce the friction, which in this class
of motors arises between the casing and the piston and parts mounted thereon.
The reduction of this friction is according to this invention attained by permitting
the casing to rotate with the piston, this being effected by arranging the casing in
such a manner that it can turn freely, so that it is taken along by, and caused to
rotate in the same direction as, the piston and the parts fixed thereto.
To enable our invention to be fully understood we will describe how it can be
carried out in practice by reference to the accompanying drawings, in which:-
Figures 1 to 3 shew as an example a rotary motor with a casing partaking of
the rotation of the piston, Figure 1 being a longitudinal section of the motor and
Figure 2 a cross section of the same, while Figure 3 shews an end view of the
casing and an end piece or bearing at the other end of the casing:
Figures 4 and 5 shew a longitudinal section and a cross section respectively of a
motor, having an outer casing and an inner one, the latter rotating concentrically
with the former within a piston corresponding to the outer casing:
Figures 6 and 7 are diagrams of the motor shewn in Figures 4 and 5 illustrating
the working of the motor.
In the motor, illustrated in Figures 1 to 3, the piston a consists of a cylindrical
body, placed eccentrically in the casing in such a manner, that it rests against the
inner side of the annular part or drum b of the casing. In the piston is inserted a
radially sliding piece c, situated between two passages, each leading from the
passages for fresh steam and waste steam respectively (the driving fluid being
supposed to be steam), which are arranged in the motor shaft, so that the space on
one side of the slide c always communicates with the steam inlet and the space on
the other side of the slide with the steam outlet.
For reducing the friction between the piston a and the slide c on the one hand
and the casing on the other hand, which casing consists of the drum b and the end
pieces b', the casing is arranged so as to rotate in the same direction as the piston.
This can be attained in many ways, the way, illustrated in the drawings, having
proved to be very suitable. On the end pieces b¹ are arranged collars or Hanges 6,
which are concentric with the ring or drum b and the outer sides of which form an
inner track for a number of yielding rings 1, placed around the flanges 6". The
outer tracks of these yielding rings are formed by the inner sides of flanges m',
arranged on the end pieces of the motor frame. The flanges m' are obviously
concentric with the flanges 62, which are eccentric with the piston and the shaft.
By employing yielding rings, a suitable tightening in the line k of contact between
the drum and the piston is obtained.
When the piston rotates, the drum b and the end pieces b¹ are taken along by
the same in consequence of the pressure at k, where only rolling friction exists.
As the movement at other contact points has the same direction, the friction is
obviously reduced.

page_text: The motor, illustrated in Figures 4 and 5, is shewn as an example of the appli-
cation of this invention to motors having an outer casing and an inner one, which
both rotate for reducing the friction at the points of contact with other parts of
the motor. As regards the outer casing b, b' and the journalling of the same, this
motor is arranged in the same manner as the motor, shewn in Figures 1 to 3.5
The outer casing corresponds to the piston a', in which a slide o moves inwards
and outwards as in the herein before described motor. In this case the piston
consists of an eccentric ring or drum in contact with the drum bat k and against
the inner side of which bears a drum p concentric with the drum b. This drum p,
together with the end pieces b', form the inner casing which surrounds a roller r,
keyed to the enlarged motor shaft g and bearing against the inside of the drum p.
In this roller are arranged passages, extending from the inlet and outlet passages
for the driving fluid in the motor shaft, the arrangement being the same as in the
hereinbefore described motor, that is to say, each passage extends from its separate
passage in the shaft and opens on one side of a partitious, which, however, is
fixed with respect to the roller r, but in which partition the slide o can move
inwards and outwards. The drums b and p are, by means of screws, fastened to
the end pieces so that they form a single piece and turn together, just like
the pistons a' and r, which are firmly connected to each other by means of the
partition s.
In the drum p is fixed a revoluble packing n, permitting the drum p to slide
to and fro upon the partitions and to occupy different inclinations with respect to
the same.
In the parts o and s are made recesses and openings as shewn in Figure 7.
In this motor the driving fluid acts on the parts o and s in three spaces, viz.,
the spaces t, u and v (see Figures 6 and 7). When the pressure surfaces of the
said parts in the spaces u and v are at a maximum (in the position, shewn in
Figures 5 and 6), the pressure surface in the space t is nil, but as the rotation
continues, the last mentioned surface increases, while the first mentioned surfaces
decrease, so that it is at a maximum, when the latter are nil (alter half a revolu-
tion from the position, shewn in Figures 5 and 6). In this position the pressure
on the surface in the space t is also acting with its greatest force. Thus it is
evident that in this motor there is no dead point, and the shaft of the motor will
be rotated by a slightly varying momentum of force.
By arranging the parts o and s in a suitable manner the motor can work with
double or multiple expansion. If the drum and the slide o are dispensed with,
the motor will obtain two pressure spaces and a more uniform turning moment.
The casing can be caused to partake of the rotation of the piston in many other
ways, for instance, by surrounding the annular part of the casing with balls or
rollers or by employing an ordinary fixed bearing.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In motors, driven by steam or other driving fluid and in which a body or
piston (or bodies or pistons) rotates within a casing or casings, arranging the casing
or casings so that they are revoluble and can rotate with the piston or pistons
with the object of reducing the friction between the piston or pistons and the
parts fixed thereto, on the one hand, and the casing or casings on the other hand,
substantially as set forth.
2. In motors of the kind referred to in Claim 1, an arrangement for mounting
the casing (or casings) in such a manner, that it can partake of the rotation of
the piston (or pistons), characterized by flanges 62 arranged on the end pieces.b
of the casing, the said flanges being concentric with the cylindrical part of the casing
and serving as inner tracks for rings surrounding the flanges, while the outer
tracks of the said rings are formed by flanges m¹ on the end pieces of the frame
of the motor, substantially as set forth.

page_text: 3. The improved rotary engines hereinbefore described and illustrated
respectively in Figures 1 to 3 and Figures 4 to 7 of the accompanying drawings.
Dated this 3rd day of December 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.