An Improved Rotary Motive Power Engine.
Year: 1892

page_text: Date of Application, 13th Feb., 1892
Complete Specification Left, 14th Nov., 1892-Accepted, 11th Feb., 1893
PROVISIONAL SPECIFICATION.
An Improved Rotary Motive Power Engine.
I, ARTHUR BOYD, of 26, Newstead Road, Middlesbrough-on-Tees, in the
County of York, Engineer, do hereby declare the nature of this invention to
be as follows:-
My invention relates to motive power engines of the rotary type, and is
principally applicable to such engines when actuated by steam, but engines con-
structed according to my invention may also be employed as gas engines.
The object of my invention is to construct a high speed rotary engine having
constant surface contact between cylinder and piston in which the defect of line
contact is overcome and running pistons over ports is obviated, as well as the
disadvantage of having delicately adjusted working parts inaccessible when the
engine is in motion or at rest.
A further object of my invention is to so combine and arrange the moving
parts and provide for the admission, distribution and exhaust of the steam or
other actuating medium that the moving parts are so balanced under the varying
pressures and the energy of the actuating medium so disposed that the engine
is free from shocks and variations of speed when worked at a high velocity, the
heavy parts having a uniform angular velocity.
Further advantages derived from the improvements constituting my invention
are that the engine can be constructed to work as a simple or compound engine and
single or double acting as desired, is reversible, and can be readily turned off the
dead centre when required to start the engine.
In describing my invention I will refer to its application to a steam engine
working in the horizontal position. In an engine constructed according to my
invention, the main shaft is compounded of two separate parts concentric with
the cylinder, one of which parts is the main driving shaft of the engine, whilst
the other part is employed in connection with certain moving parts of the engine
in the manner hereinafter described, and which for distinction I will term the drum
shaft.
The cylinder and its covers which serve as a fly wheel are secured axially to and
rotate with the main driving shaft. This shaft is carried in bearings formed on
the outer fixed casing or frame, but is free to revolve upon the drum shaft for
which purpose the cylinder cover at that end extends outwardly in the form of a
hollow shaft. The drum shaft passing through the hollow shaft is furnished within
the cylinder with a drum or barrel which receives the inner end of the driving
shaft, so that the driving shaft and drum shaft are kept in line and each shaft
revolves independently of the other shaft in the manner required for the purposes
of my invention. The annular space between the cylinder and drum is divided
into two chambers by radial longitudinal walls or partitions projecting as fixtures
from the cylinder to work against the drum; other intermediate wings or partitions
extend radially as fixtures from the drum to work against the cylinder and cylinder
covers, all the partitions or wings being fitted and packed so as to be steam tight.
Inlet and exhaust ports are furnished at one end of the fixed casing or frame so as
to be opened and closed as suitable openings provided in the adjoining cylinder
cover pass over them. At the opposite part of the engine and outside the fixed
casing or frame, levers are provided, one fixed to the hollow shaft extending from
and forming part of the cylinder cover so as to be carried round with the rotation
of the cylinder, and the other fixed to the drum shaft. These levers are connected
by links or rocking bars to opposite parts of an eccentric strap which is carried

page_text: round a disc or its equivalent projecting eccentrically from the engine casing or
frame onto which it is cast or otherwise secured.
The action of the engine is as follows:-As the cylinder revolves, steam is
admitted into the space enclosed between a partition attached to the cylinder, and
a partition attached to the drum, and by a port or passage through the drum,
is simultaneously admitted to the corresponding space between the opposite
partitions.
According to the position of the eccentric, one of each pair of partitions offers
less resistance to the steam acting upon it than the other, that is to say, that
although the pressure on each resisting surface is equal, the greater mechanical
advantage afforded by the position of the eccentric to the lever affected by the
motion of one partition enables that partition to move forward and to bring the
other partition after it at a relatively slower speed. As the eccentric advances
this mechanical advantage is transferred to the other partition, the relative speed
of which is accelerated and the two partitions approach each other as the steam
exhausts from the diminishing space between them and live steam enters the
increasing space outside of them; a process which is continuous as the cylinder
rotates uniformly. The above description applies to a double-acting simple
engine.
In order to compound the engine, a circular division plate is provided, dividing
the annular space into two lengths, the relative capacities of which can be adjusted
as desired according to the position selected for the circular division plate.
Should the engine stop on the dead centre, that is when the levers connected to
the eccentric strap are in a position of equal mechanical advantage relatively to
each other, the engine can be started to rotate in either direction by turning the
eccentric on its centre to the right or left as the case may be, thereby altering the
mechanical advantage of the levers before steam is applied, this being effected
without moving the main shaft and its load.
It must be understood that I do not restrict myself to the precise construction
of a rotary engine as herein before described, as my improved rotary engine can
be varied in several details of construction without departing from the nature of
my invention, as for instance more than two pistons may be used in the engine;
two or more engines can be connected in line to actuate the same driving shaft,
thereby increasing the power and overcoming a dead centre; a number of rigid
cylinders may be used as above described to form a multiple compound engine
Steam can be admitted and exhausted at either or both ends of a cylinder: and
lastly the levers on the main and drum shafts may be connected to any suitable
arrangement of moving parts by which the requisite variation in their relative
mechanical advantage is obtained in the manner already described with reference
to their connection to an eccentric or its equivalent.
Dated this 12th day of February 1899
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improved Rotary Motive Power Engine.
I, ARTHUR BOYD, of 26, Newstead Road, Middlesbrough-on-Tees, in the County
of York, 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 :-
My invention relates to motive power engines of the rotary type and is principally 5
applicable to such engines when actuated by steam.
The object of my invention is to construct a high speed rotary engine capable of
-working- smoothly on the single-acting principle,-having-efficient surface contact
between the driving cylinder and resistance pistons and in which the defect of

page_text: running pistons over ports is obviated, as well as the disadvantage of having
delicately adjusted working parts inaccessible whether the engine is in motion or
at rest.
A further object of my invention is to so combine and arrange the moving parts
and provide for the admission, distribution, and exhaust of the steam or other
actuating medium that the moving parts are balanced under the varying pressures,
whereby the packing is not subject to undue wear and the energy of the actuating
medium is so disposed that the engine is free from shocks and variations of speed
when running, the heavy parts having a uniform angular velocity. Further
advantages derived from the improvements constituting my invention are that the
engine can be constructed to work as a simple or compound engine, is reversible,
and can be readily turned off the dead centre when required to start the engine
without moving the main shaft and its load.
In the accompanying drawings I illustrate my invention as applied to both a
simple and a compound single-acting engine and show separately some of the parts
all designed for working in the horizontal position, from which it will be readily
understood how the engine can be modified in design to work in the vertical or
inclined position if so required. I will first proceed to describe my invention as
applied to a single-acting simple engine of which a longitudinal sectional view is
illustrated in Figure 1, corresponding to which Figure 2 is a transverse sectional
view taken on line of Figure 1 with the pistons shown in the starting position,
and in this respect does not correspond with the position of the parts shown in
Figure 3 which is a transverse view taken on line y y of Figure 1.
a is the main shaft, the rotary motion of which is the power of the engine to be
utilized. In this case the main shaft a is made hollow for the reception of the
shaft b which employed in connection with certain moving parts of the engine
in the manner hereinafter described and which for distinction I will term the
resistance shaft. These two shafts are fitted or coupled together to revolve in
line with relatively different rotary motions. The cylinder c and its covers c¹ care
secured axially to and rotate with the main or driving shaft a, their combined
weight serving as a flywheel to the engine. The resistance shaft rotating within
the main shaft a is furnished within the cylinder with a drum or barrel d. The
annular space thus formed is occupied by radial longitudinal walls or partitions e¹ e³
projecting as fixtures from the cylinder to work against the drum and which are
the working pistons of the engine, between which are other intermediate wings or
partitions, which are the corresponding resistance pistons for the same
direction of rotation, and which extend radially as fixtures from the drum to
work against the cylinder and cylinder covers; all the partitions or wings being
fitted and packed so as to be steam tight without excessive friction. ¹ is a port
through the drum to equalize any pressure which may be set up against the pistons,
u' being relief ports to reduce such pressure to a minimum.
A convenient form of mounting the cylinder c, and the main shaft a with their
accessory moving parts is shown in the drawings and consists of a cylindrical
casing with end covers a' g¹ erected on a bedplate and forming a chamber in
which the cylinder c revolves. k is the port in the cylinder cover which is shown
in Figure 1 exactly opposite to the inlet port k¹; being the outlet port. The
relative positions and areas of these ports as they appear in the face of the cover y¹
are shown in Figure 4.
For structural compactness the casing 9 is preferably constructed concentrically
with the cylinder c and main shaft a, and is furnished with the usual glands,
packings and metal bearings required in high speed steam engines, including a gland
springs for holding the cylinder face up to its work, which gland spring is dispensed
with if the steam is supplied in the casing when the steam pressure behind the
cylinder cover serves the same purpose. h¹h are standards erected on the
engine bedplate, of which h' is simply furnished with bearings for the disc end of
the main shaft a to take up the oblique stress due to the linkwork, whilst his
specially constructed for the reception of the eccentric 4, by which to adjust the

page_text: relative leverage and movements of the links and levers m³, m³, m³, and m², which
are shown in Figure 3, by which the lead, cut off, exhaust and compression of the
steam is regulated and controlled and the engine reversed, and for which purpose
an index and pointer are useful when provided in the position shown.
In practice the parts being constructed and arranged as shown and described
they are intended to operate as follows:-The engine having been adjusted on its
axis by turning the wheel n if necessary so that the pistons are in the starting position
as shown in Figure 2, the steam enters the space between the pistons e' f' and through
the port k³ to the corresponding space between the pistons ef. It is obvious that the
effect of the steam so admitted is to force the pistons e and and their companion
pistons and f as far apart as possible, and that the pressure of steam on both pistons
in each case is necessarily equal and the cylinder in pressure balance, but in order to
obtain useful work from the steam the equal pressures on the said pistons do not meet
with equal resistance, that is to say that the steam pressure during admission and
expansion meets with a lower resistance from the pistons e¹e which are the working
pistons than from the pistons f₁f which are the resistance pistons. Upon this
differential piston resistance depends the efficiency of the engine and the special
combination or arrangement of parts by which it is brought into effect constitute
an important part of my invention which I will now proceed to describe, and which
are illustrated in section in Figure 1, with a corresponding transverse view in
Figure 3. The disc is keyed to the main shaft a and is made heavy enough and
properly balanced to serve as a flywheel; m', m², m³, and m* constitute a system
of links and levers arranged and adjusted to operate in combination with the
shafts a and b, so that whilst the steam imparts a uniform angular velocity to the
pistons and therefore to the cylinder é and main shaft a, the resistance shaft >>
revolves with a varying velocity corresponding to the variations of space between
the pistons and the pistons e' e as steam is admitted, expanded and exhausted
within the engine cylinder. The pin is secured to the disc wheel n and is there-
fore directly connected like a crank pin to the main shaft a, the pin p' is similarly
directly connected through the lever to the resistance shaft b, the link m¹ being
in constant compression and the link m' in constant tension when the engine is going
ahead as shown by the arrows in the figures, and rice-cers when the engine is
running in the opposite direction The controlling shaft o is placed eccentrically
to the axis of the main shaft a, round which it can be moved at a constant radius in
the stand h³. The pins p¹² are coupled together by the system of links m³, m³, and
cross lever m² as shown more particularly in Figure 3.
Taking this system of levers and links as shown in Figure 3 to represent a position
of the pistons at which the steam is giving out work, it will be seen that pressure of
steam upon the pistons el e² which is transmitted to the pin has mechanical
advantage over the pressure of steam upon the pistons f¹which is transmitted
to pin p, and that as the system of links revolve this mechanical advantage reaches
the vanishing point, and is then transferred to the pistons fif for the remainder
of the revolution of the main shaft, after which it reverts to the pistons el e' as
before for the like part of another revolution, thus passing through two vanishing or
neutral points in each revolution, which neutral points are the dead centres of the
engine. In that part of a revolution through which the mechanical advantage is
with the pin, that is with the pistons e¹ e², the steam is entering into and
expanding within the steam spaces of the cylinder by driving the working pistons e¹ e'
in advance of the resistance pistons ff, and in the remaining part of the revolution
in which the mechanical advantage is against the pin p', the exhaust steam is being
swept out of the cylinder by the pistons advancing or closing up to the
pistons ee, that is to say the resistance pistons f¹ have a reciprocal motion
relatively to the working pistons ele as they all revolve together, the said pistons ee³
nevertheless having a uniform angular velocity which is accordingly transmitted to
the main shaft a.
The combined eccentric and worm wheel g' with worm q² and hand wheel is a
useful arrangement for changing the angular position of the controlling shaft o,

page_text: thereby moving the pin p³ with its lever m³ and therefore the pistons ff without
moving the main crank pin p', the engine being in consequence either altered in
grade of expansion, or reversed as shown by the pointer, this can be done when the
engine is going, that is to say, the controlling shaft o is altered in position relatively
to the fixed inlet and outlet ports k k in the casing cover g'. The whole engine
is in mechanical balance by means of counter balances for which purpose the lever m³
has the slotted extension shown in Figure 3.
Having now described a single-acting simple engine complete in all its parts as
constructed according to my invention, I will now proceed to describe Figures 5 to 7
inclusive, which illustrate my invention as applied to a compound engine. In order
to compound the engine I add to the steam cylinder c the part e divided there-
from by the intermediate partition c. Taking c as the high and c³ as the low
pressure cylinders respectively, their relative capacities can be obviously adjusted
to suit any conditions within practical limits under which the steam is to be
expanded, and in Figure 5 the capacities of these cylinders are shown in the
proportion of about three to one. The steam exhausted from the high pressure
cylinder passes through the pipe into a receiver r, from which it is delivered
through the admission pipe into the low pressure cylinder c. In other respects
my invention involves no essential differences in the arrangement of parts or
combination of details suitable to either a simple or compound single-acting engine,
the relative action of the pistons under steam pressure in combination with a main
and resistance shaft being precisely similar in either case.
The modifications of the arrangement of parts for admitting and clearing the
steam from the cylinder or the precise means for adjusting the piston resistance in
the manner as herein before described which are shown in the drawings must be
taken as equally applicable to either a single or compound engine, but for con-
venience of illustration one arrangement of these details is shown in Figures 1 to 3
as parts of a simple single-acting engine, whilst other modifications are shown in
Figures 5 to 7 as parts of a compound single-acting engine. I wish it to be
understood that I do not restrict myself to the precise details or arrangement of
parts as hereinbefore specified and illustrated in either case as these details admit
of various modifications consistent with the main features of my invention both with
regard to the arrangement and position of the passages and ports for admitting and
exhausting the steam from the cylinder, and also in the combination of parts for
providing the same piston resistance against the steam as has already been described
with reference to the system of links shown more particularly in Figure 3.
Figures 5 and 7 however illustrate a modified arrangement of the ports for
admitting and clearing the steam from the cylinder which is thought to have
practical advantages such as small surface friction. In this modification the valve
consists of a cylindrical casing v enclosing an annular space k round the main
shaft a, which casing is flanged up to the cylinder cover, the ports k of which lead
direct from the annular space to the cylinder steam space. is the valve liner
which screws into the casing cover g', and can be screwed round by the lever t¸ to
any position whether for adjusting the cut off of the steam, stopping or reversing
the engine, the proper positions for which are marked on the index . In order to
effect its purpose the valve and its connections are furnished with the following
arrangement of ports.
Referring more particularly to Figure 7, is the port in the valve v which
passes over the ports k and k in the valve liner v' to the inlet and outlet ports k¹³
in the casing cover which take the form shown in Figure 7 to admit of the
valve liner ports being set to different positions as required. The above
described provision for adjusting the cut off of the steam and for stopping or
reversing the engine serves all the purposes of the angular adjustment of the con-
trolling shaft o, except that with the shaft o fixed in position the engine cannot be
turned off the dead centre without moving the main shaft and its load, all provision
for which as described with reference to Figure 1 is omitted in Figure 5. When the
engine is going ahead as shown by the arrows in Figures 2, 3 and 6, the steam acts

page_text: directly on the working pistons e¹³, the reaction being sustained by the resistance
pistons ff, and the uniform angular velocity of the main shaft is converted
into the variable velocity of the resistance shaft b, but when the engine is
reversed f¹f become the working pistons and e' e the resistance pistons, and the
variable angular velocity of the resistance shaft bis converted into the uniform!
angular velocity of the main shaft a.
It will be observed in Figures 8 and 9, that a modified arrangement for coupling
the pins p p is shown in which a grooved cross lever m' takes the place of the
cross lever m² in Figure 3, in which the pins p' p³ reciprocate as they revolve
together.
By constructing the cylinder in the manner shown in Figure 6, in which c³ is a
detachable part with the piston e, the interior of the cylinder is made easily
accessible for inspection and repair.
Having thus fully described my said invention and the manner of performing the
same, I wish it to be understood that I am aware that the method or principle of 1
obtaining useful work from steam by the differential resistance of revolving pistons
I therefore make no claim to such method or principle otherwise than
as embodied in and carried into practice by my improvements as above specified.
What I claim and desire to secure by Letters Patent is :-
is not new,
:-
Firstly In rotary motive power engines a combination of parts in which a
main shaft and resistance shaft are coupled together to rotate in line, the driving
cylinder with the working pistons attached thereto being axially secured to the main
shaft, whilst resistance pistons are secured to the resistance shaft; the two shafts
being connected endwise to a system of links and levers or their equivalents
revolving about a centre eccentric to the said shafts by which the uniform angular :
velocity of the main shaft is converted into a variable angular velocity of the
resistance shaft, the whole system being driven by the crank pin p' of the main
shaft when the engine is running ahead. And when the engine is reversed the
variable angular velocity of the resistance shaft is converted into the uniform
angular velocity of the main shaft, the whole system being driven by the crank
pin p of the resistance shaft, all substantially as hereinbefore described with
reference to the accompanying drawings.
Secondly-In rotary motive power engines the use in combination with the main
and resistance shafts a and b of the system of links and levers m', m³, m³, and m²,
connected to the pins pl p³, and revolving about the controlling shaft o as a centre 3
which is placed eccentrically to the said main and resistance shafts, all combined
and operating together to vary the motion of the said resistance shaft in the manner
and for the purpose as hereinbefore described and illustrated in Figures 1 and 3 of
the accompanying drawings.
Thirdly In rotary motive power engines the use in combination with the
main and resistance shafts of the system of links and levers m², m³, m³, and_m²,
connected to the pins p³ p², and revolving about the controlling shaft o as a movable
centre which is held at a constant eccentricity to the common axis of the main and
resistance shafts but capable of angular adjustment thereto, whereby the engine is
reversed and the lead, cut off and exhaust and compression of the steam is con- 4
trolled and regulated, substantially as hereinbefore described with reference to
Figure 1 of the accompanying drawings.
Fourthly In rotary motive power engines the use and construction of the
cylindrical or annular valve formed by enclosing an annular space * round the
main shaft a, which cylindrical valve is fitted into a liner which is adjustable 5
within the casing g', the several parts being furnished with ports k, k², k, k, and k²,
and all combined and fitted together and to the cylinder end in the manner as
herein before described with reference to Figures 5 and 7 of the accompanying
drawings.
Fifthly:The combination of parts as a whole, constructed, arranged, and 5
fitted together and constituting a single-acting simple rotary motive power engine

page_text: as hereinbefore described with reference to Figures 1 to 4 of the accompanying
drawings.
Sixthly-The combination of parts as a whole, constructed, arranged, and
fitted together and constituting a compound single-acting rotary motive power
5 engine as hereinbefore described with reference to Figures 5 to 7 of the accom-
panying drawings.
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