Improvements in Rotary Engines.
Year: 1891

page_text: Date of Application, 7th Aug., 1891
Complete Specification Left, 9th May, 1892-Accepted, 11th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Rotary Engines.
I, ALEXANDER FRANCIS GARDEN BROWN, of Swindridge Muir, Dalry, in the
County of Ayr, Gentleman, do hereby declare the nature of this invention to be as
follows:-
This invention is a development of the improvements in rotary engines described
in the Specifications of Letters Patent 1555 of 1888 and 16913 of 1889 and it has
for its object mainly to ensure that the engine will start at any part of the revolution,
that the rotating parts will be properly balanced, and that the arrangements for
reversing may be simplified.
To that end the cylinder is fitted with a series of pistons or a multiple piston
composed of two, three or more short cylindrical piston blocks separated by discs which
closely fit the inside of the cylinder the said piston blocks being evenly distributed on
the discs around the axis of the cylinder with their axes parallel thereto, so as to
resemble the crank pins of a multiple throw crank and being preferably of half the
diameter of the cylinder to obtain the maximum stroke and efficiency.
The pistons and discs are in a piece or rigidly attached together and to discs at
each end to which the engine shaft is secured in any suitable manner but preferably
by pins or bolts fitted to permit of such play that oscillations or vibrations of the
rotating pistons will not be communicated to the shaft. The discs practically
divide the cylinder into a series of compartments of short cylinders each of which is
fitted with oscillating arms or abutment plates constructed and fitted as described
in the Specifications before mentioned so that their ends bear on the peripheries of
the cylindrical blocks or pistons the admission and exhaust of the steam to each
compartment being also effected as in the engines described in said Specifications.
The valve gear is or may be of the form described in the Specification filed with my
applications for Patents 1163 of 1891 and 12089 of 1891 and is arranged to supply
steam to the series of compartments.
The engine is made reversible by fitting each compartment of the cylinders with
duplicate arms or abutment plates and by suitably arranging the distributing valves
the steam may be expanded from a central compartment to those on either side or
from compartment to compartment of the series to form a multiple expansion
engine.
In another modification the pistons instead of being cylindrical are of a form
approximating to that of any of the pistons shewn in the engines described in the
Specifications of Patents 1555 of 1888 and 16913 of 1889 and are keyed on a spindle
passing axially through the cylinder; and they are either attached to discs fitted to
rotate with them in the cylinder or separated by webs or partitions formed in the
cylinder and serving to divide it into compartments.
The construction of piston in both modifications described is applicable to rotary
engines generally.
Dated this Sirth day of August 1891
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Rotary Engines.
I, ALEXANDER FRANCIS GARDEN BROWN of Swindridge Muir, Dalry in the
County of Ayr, Gentleman, 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 is a development of the improvements in rotary engines described
in the Specifications of Letters Patent 1555 of 1888 and 16913 of 1889 and it has
for its object mainly to ensure that thejengine will start at any part of the revolution,
that the rotating parts will be properly balanced, and that the arrangements for
reversing may be simplified.
In the accompanying drawings which show a multiple expansion engine constructed
in accordance with my invention Figure 1 is a vertical cross section, Figure 2 a
longitudinal vertical section and Figure 3 a part plan and part section through the
valve casing. The engine cylinder A. is fitted with a series of pistons or a multiple
piston composed of two three or more short cylindrical piston blocks B' B2, B3
separated by discs, which closely fit the inside of the cylinder the said piston blocks
being evenly distributed on the discs around the axis of the cylinder with their axes
parallel thereto, so as to resemble the crank pins of a multiple throw crank and
being preferably as shown at Figure 1 of half the diameter of the cylinder to obtain
the maximum stroke and efficiency.
The pistons B1, B2, B3 and discs b', 2, 3, 4 are in a piece or rigidly attached
together. The discs 3, at each end to which the engine shaft C is secured, in
any suitable manner, but preferably by pins or bolts c, are so fitted to permit of
such play that oscillations or vibrations of the rotating pistons will not be communi-
cated to the shaft. The discs b¹, 1, 1³, practically divide the cylinder into a
series of compartments of short cylinders A', A2, A3 each of which is fitted with
oscillating arins or abutment plates D, constructed and fitted as described in the
Specifications before mentioned so that their free ends bear on the peripheries of
the cylindrical blocks or pistons the admission and exhaust of the steam to cach
compartment being also effected as in the engines described in said Specifications.
The valve gear is preferably of the form described in the Specification of Letters
Patent 1163 of 1891 and is arranged to supply steam to the series of compartments.
The engine is made reversible by fitting each compartment of the cylinders with
duplicate arms or abutment plates D,-and by suitably arranging the distributing
valves the steam may be expanded from a central compartment to those on either
side or from compartment to compartment of the series to form a multiple expansion
engine.
In the example shown the steam distributing valves E, E are of the rotary type
and the valve chests are divided by webs e', e², es into compartments E', E, E, E*
the live steam entering by a port in the compartment El to the first compart-
ment A of the cylinder thence exhausting through the port to the valve com-
partment E and by the port f³ to the second compartment A of the cylinder thence
through the port to the valve compartment E3 through the port f to the third
compartment A3 and finally exhausting through the port f to the compartment E.
The valves are rotated by spur wheels G keyed on their spindles and geared with
a pinion which is thrown into gear with either spur wheel G the one valve or
the other being rotated according as the engine is to be driven in one direction or
the other.
In another modification shown diagrammatically at Figure 4 the pistons B¹, B', B³
instead of being cylindrical are of a form approximating to that of any of the
pistons shewn in the engines described in the Specifications of Patents 1555 of
1888 and 16913 of 1889 and are keyed on a spindle C passing axially through the
cylinder, and they are either attached to discs fitted to rotate with them in the

page_text: cylinder or separated by webs or partitions formed in the cylinder and serving to
divide it into compartments.
In either form of the engine the pistons may be all of equal length and high
pressure steam supplied direct to each compartment of the cylinder.
The construction of piston in both modifications is applicable to rotary engines
generally.
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. The combination of parts constituting the improved rotary engine herein
described under different modifications.
2. A rotary engine having a piston composed of a series of short cylindrical or
cam blocks separated by discs dividing the cylinder into compartments substantially
as described.
3. In a rotary engine a compound or multiple piston constructed and arranged
to be operated substantially as described.
Dated this Seventh day of May 1892.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.