Improvements in Rotary Engines.
Year: 1897

page_text: Date of Application, 8th May, 1897
.
⚫ Complete Specification Left, 9th Dec., 1897-Accepted, 5th Mar., 1898
PROVISIONAL SPECIFICATION.
Improvements in Rotary Engines.
I, ANDREW MITCHELL, of Longside, in the County of Aberdeen, Scotland, do
hereby declare the nature of this invention to be as follows:-
1
This invention for improvements in rotary engines, has for its object to provide
a compact rotary motor in which the motive fluid employed may be either steam,
gas, or compressed air, suitable for driving engineer's machine tools, motor cars
and the like, and comprises a cylinder having a cam shaped internal surface and
provided with valves in connection with explosion chambers formed in the cylinder,
or steam or compressed air supply; a disc or cylinder, provided with inwardly
directed openings and abutments diametrically opposed, keyed to the motor shaft
which passes through the centre thereof; and a reciprocating piston sliding in
the plane of the disc consisting of parallel side plates between which solid end
blocks are suitably secured, the side plates being widened and slotted at the centre
of their length with elongated openings through which the motor shaft passes; or
instead of the side plates a single rod may connect the two ends of the piston and
pass through a hole in the motor shaft. The piston is provided at each end with
rollers consisting of either a single roller rotatably mounted in a suitable socket
or a pair of rollers similarly mounted in a bar of segmental shape in cross section
and capable of oscillating in its seat in the end of the piston. A packing roll is
inserted in a hollow of the segmental bar between the said bar and the inner sur-
face of the cylinder. The rollers may if desired be replaced by spring packing.
The abutment disc in which the piston reciprocates has a part of its periphery
constantly in contact with the cam portion of the inner surface of the cylinder so
that the piston on being rotated against the cam surface is in a position flush with
the outer edge of the abutment disc at one end and at the other, which projects
through the distance between the abutment disc and the inner surface of the
cylinder, is exposed to the action of the motive fluid. The piston during rotation
is reciprocated relatively to the abutment disc.
The valves, which are situated in the cylinder and actuated by means of a cam,
consist of a supply valve situated at the top or other convenient part of the cylinder
and the admission valves situated on opposite sides of the cylinder and opened
for admission or exhaust according to the direction in which it is desired to rotate
the motor shaft. The cam for actuating the valves is fixed between two collars
keyed on the motor shaft and operates on levers held in contact therewith by
springs, and giving a reciprocating motion to rods connected by links with the
valve levers. A second cam is removably inserted between the collars on the
opposite side of the shaft to that on which the first cam is fixed if it is desired to
give two impulses in one revolution, one on each end of the piston.
When gases are used the supply valve is opened and shut at each revolution
by a short cam and lever so that the explosion chamber is filled and the port closed

page_text: before the admission valve is opened. On opening the admission valve an electric
spark is caused to pass and ignite the gases.
Dated this 8th day of May 1897.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
Improvements in Rotary Engines.
I, ANDREW MITCHELL, of Longside, in the County of Aberdeen, Scotland,
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 for improvements in rotary engines, has for its object to provide
a compact rotary motor in which the motive fluid employed may be either steam,
gas or compressed air, suitable for driving engineer's machine tools, motor cars
and the like, and comprises a cylinder having a cam shaped internal surface and
provided with valves in connection with explosion chambers formed in the cylinder,
or steam or compressed air supply; a disc or cylinder provided with inwardly
directed openings and abutments diametrically opposed, keyed to the motor shaft
which passes through the centre thereof; and a reciprocating piston sliding in
the plane of the disc consisting of parallel side plates between which solid end
blocks are suitably secured, the side plates being widened and slotted at the centre
of their length, with elongated openings through which the motor shaft passes; or
instead of the side plates a single rod may connect the two ends of the piston and
pass through a hole in the motor shaft. The piston is provided at each end with
rollers consisting of either a single roller rotatably mounted in a suitable socket
or a pair of rollers similarly mounted in a bar of segmental shape in cross section
and capable of oscillating in its seat in the end of the piston. A packing roll is
inserted in a hollow of the segmental bar between the said bar and the inner sur-
face of the cylinder. The rollers may if desired be replaced by spring packing.
The abutment disc in which the piston reciprocates has a part of its periphery
constantly in contact with the cam portion of the inner surface of the cylinder so
that the piston on being rotated is in a position flush with the outer edge of the
abutment disc at one end and at the other, which projects through the distance
between the abutment disc and the inner surface of the cylinder, is exposed to the
action of the motive fluid. The piston during rotation is reciprocated relatively
to the abutment disc.
The valves, which are situated in the cylinder and actuated by means of a cam,
consist of a supply valve situated at the top or other convenient part of the cylinder
and the admission valves situated on opposite sides of the cylinder and opened
for admission or exhaust according to the direction in which it is desired to rotate
the motor shaft. The cam for actuating the valves is fixed between two collars,
on the motor shaft and operates on levers held in contact therewith by
springs, and giving a reciprocating motion to rods connected by links with the
valve levers.
When gases are used the supply valve is opened and shut at each revolution
by a short cam and lever so that the explosion chamber is filled and the port closed
before the admission valve is opened. On opening the admission valve an electric
spark is caused to pass and ignite the gas. It will be obvious that the motor may
also be used as a pump.

page_text: Fig. 115, a side elevation or a rotary motor constructed according to this in-
vention, with side cover plate removed.
Fig. 2 is a section on line A-B of Fig. 1.
Fig. 3 is a side elevation of one form of valve mechanism.
Fig. 4 is a side elevation showing another form of valve mechanism.
Fig. 5 is a detail view of one of the valves.
Fig. 6 is a sectional elevation showing ports of a motor when used as a pump
or motor for working in one direction only.
Fig. 7 is a somewhat similar view to Fig. 6 showing part of a motor for liquids
with valves for same.
Figs. 8 and 9 show different forms of friction rollers for piston.
Figs. 10 and 11 are detail views of the valve actuating mechanism.
The main cylinder or casing a is constructed to form a chamber a¹, eccentric
to the axis of the casing, in which is mounted the disc b keyed to the motor
shaft and carrying the piston d. The shaft c, and disc b provided with
inwardly directed openings e and abutments f, are mounted eccentrically to the
chamber at in the casing a and concentrically with the axis of the casing so that
some part of the periphery of the disc is always in contact with the top of the
chamber a and forms therewith a steam tight joint, by the interposition of a
movable packing piece held in position against the disc b by springs or screws h.
A crescent-shaped chamber is thus formed in the casing. The piston d is guided
in the openinge of the disc band reciprocates relative thereto both its ends being
in contact with the interior of the casing a. It is formed of parallel side
plates, slotted longitudinally at i, and between which end blocks are secured.
The ends of the piston are fitted with spring packing j¹ or friction rollers con-
sisting of a single roller held in a suitable socket or a pair of rollers k¹¹ with
packing between, held in an oscillating bar seated in the end of the piston
as shown in Figs. 8 and 9. The valves 1 m n for supply, admission and exhaust
respectively fitted in the casing a where gases are used, or in the supply pipe o
in the case of liquids, are shown of the oscillating type although slide valves
may be employed. When the motor is used for liquids, the ports o¹ and
valves 1mn are constructed as shown in Figs. 6 and 7.
The valve mechanism is actuated by the shaft c of the motor and comprises a
fast collar q keyed to the motor shaft and a loose collar r. Fixed to the loose
collar rare one or two eccentric pins s (according as it is desired to give one or
two impulses to the piston in one revolution) acting on levers t pivoted at u
to the casing a and pulled towards each other at their opposite ends by a spring v
and connected by links wwl with the arms ar fixed to the valves mn. It will
be seen that the spring v, by pulling levers tt inwards, tends to close the
valves mn.
The links ww may be pivoted in any of the holes 1 in the levers tt' according
as it is desired to lengthen or shorten the travel of the links ww¹ and thus the
oscillation of the valves. In order that the pins s may be adjusted to operate the
valves at the proper time for steam admission, according to the direction of
rotation of the motor, the fast collar q is slotted at 2 for the reception of a screwed
pin 3 in the loose collar r so that the collar with the pins s may be rotated on
the shaft c and fixed by the screw 3 being screwed tight in any position between
the extremities of the slot 2. The supply valve is operated by a handle 4 and
may be connected with any form of governor. A cam y mounted on the casing a
between the levers tt is operated by a handle for reversing the motor by holding
one or other of the levers t t out of engagement with the pins s, and opening
the valve connected therewith for exhaust.
In the modified construction of valve mechanism shown in Fig. 4 a fast
collar by means of slot 2 and pin 3 actuates a cam 9 loosely mounted on the
shaft c, which operates on rollers 5 on the ends of the arms xx¹ fixed to the valves,
the reversal being effected in this case by a rod 6 connecting arms 7 fixed to the

page_text: valves, opposite the arms and provided with rollers 8, the arms 7 being acted
upon by springs 10, which close the valves and hold the rollers 5 in contact with
cam 9.
Ignition chambers 11 are formed in the casing a for use when gases are employed
as the motive fluid, and the supply valve is opened and shut at each revolution
and half revolution by means of a short cam and lever, so that the explosion
chamber is filled and shut before the admission valve is opened. An electric
spark is caused to pass and ignite the gases by the opening of the admission
valve m.
In operation, supposing it is desired to drive the motor in the direction of the
arrow, valve n is opened and held open for exhaust by rotating the cam y against
the lever which operates link w¹ and arm a¹ of valve n. The admission valve m
is closed until the pin s or cam 9 comes against lever t which operates the valve
through link w and arm x. When the admission valve is opened the piston is
in the position shown in dotted lines in Fig. 3 and is driven to the
position shown in Fig. 1 before the valve commences to close under the
action of the spring, finally the valve is closed and the expansion of the motive
fluid in the cylinder completes the stroke of the piston. To reverse the direction
of the motor the supply valve is closed and the pins s or cam 9 as the case may
b. are placed in the proper position for operating lever t¹, by loosening screw 3
and partly turning back collar r or cam 9.
The cam y is then rotated against levert and opens valve m for exhaust as
will be readily understood. In the modified form of reversing mechanism shown
in Fig. 4 the bar 6 is simply pushed over when reversing.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
'I claim is :-
1. A rotary engine for steam, gases or liquids comprising an outer casing
having a cam shaped internal surface, an inner disc mounted on the motor shaft
in the casing with a part of its periphery in contact with the inner surface
thereof, a piston rotating with the disc and reciprocating relative thereto, and
valves for supply, admission and exhaust arranged and constructed substantially
as described.
2. In rotary engines the valve actuating mechanism substantially as described
with reference to the drawings.
3. The improvements in rotary engines substantially as described with reference
to the drawings.
Dated this 9th day of December 1897.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C.,