IMPROVEMENTS IN STEAM ENGINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Alfred Hoyois at the Office
of the Commissioners of Patents on the 24th May 1883.
ALFRED HOYOIS of Clabecq, in the Kingdom of Belgium, Civil Engineer,
"IMPROVEMENTS IN STEAM ENGINES."
My invention relates to that class of steam engines in which there are two inlet
and two exhaust valves, the cylinder covers forming chambers through which the
steam is admitted to the engine-and it consists in the improvements hereinafter
described in the construction and arrangement of the inlet and exhaust valves and
in the means and devices or apparatus for operating the same.
In the inner side or end of each of the chambered cylinder covers, is a central
circular hole or opening in which is fitted a metal tubular piece traversed by the
piston rod and forming with the said circular hole or opening an annular space or
port conducting from the said chambered cover into the cylinder.
Mounted on the outer surface of the said metal tubular piece is a cylindrical
valve pressed down upon its seat by two spiral or other suitable springs so as to
close the annular port hereinbefore described, the said valve being raised or opened
when required by the operating mechanism hereinafter described. Each of the
said valves is, by rods passing through the outer cylinder covers, connected to the
arms of a forked lever extending downwards from a horizontal longitudinal bar
capable of reciprocating motion in suitable bearings upon the top of the cylinder,
by causing either of the said bars to move outwards, that is, towards the end of
the cylinder, it will act upon the valve to which it is connected and open it and
steam will be admitted to one end of the cylinder. The said bars receive motion
to open the steam valves from an eccentric mounted on the crank shaft of the
engine, the end of the eccentric rod being connected to the pin of a crank affixed
upon a horizontal spindle suitably supported and extending above and across the
cylinder from the side to near its centre line and having upon its other end a!
second crank, the pin of which extends across the centre line of the cylinder and
forms the axis of two L shaped pawls, the horizontal arms of which project one
towards each end of the cylinder and are formed so as to be capable of engaging.

page_text: alternately with a catch formed on the inner end of each of the horizontal bars
herein before described; the upper arms of the said pawls are curved outwards and
project upwards to between two stops carried by and rising and falling with the
governor according as the speed of the engine increases or diminishes.
The action of the apparatus is. as follows: By the rotation of the crank shaft of
the engine the eccentric is caused to impart an oscillating motion to the horizontal
spindle above the cylinder and the said spindle through the crank upon its inner
end gives a reciprocating motion to the two pawls upon its crank pin and the
horizontal projecting arms of the said pawls engage alternately with one or other
of the longitudinal bars connected to the steam valve and force it backwards, thus
causing each of the steam valves to open alternately and admit steam to each end
of the cylinder-When the steam valve operated upon has been opened to the
required extent, the arm projecting upwards from the pawl now engaged comes in
contact with one of the stops carried by the governor and is thereby arrested,
causing the arm of the pawl now engaged with the horizontal bar, to rise from the
end of the said bar and release the same, the steam valve is then closed by the
action of its springs, and the steam is cut off.-The continued rotatory motion of
the crank shaft causes the eccentric to give motion in a contrary direction to the
pawls and the second pawl then engages with the other horizontal bar and opens
the other steam valve admitting steam to the other side of the piston and the
steam valves are opened to a greater or less extent according as the stops are
raised more or less by the governor, the curved vertical arms of the pawls coming
sooner or later into contact with the said stops according as the said stops are
higher or lower for the time being.
In order to prevent the injurious effects arising from too sudden changes in the
action of the governor, I arrange two blocks so that they act as a brake upon a
rotatory socket upon the governor spindle, the pressure of the said blocks being
regulated by springs acted upon by suitable screws.
The exhaust ports of the engine are formed at the lower side of the cylinder
next to the chambered covers and the said exhaust ports are alternately closed and
opened by slide valves working in and out of chambers formed to receive them in
the lower part and within the ends of the cylinder, the said slide valves are
connected together by a rod forined so as to open one of the said ports and close
the other simultaneously. The said rod extends in front of the cylinder where it
is jointed to one end of a connecting rod, the other end of which is jointed to the
lower end of a lever forming part of a three armed lever mounted on an axis
perpendicular to the centre line of the cylinder and upon which it is capable of
oscillating, the other two arms of the said three armed lever project in a nearly
horizontal direction slightly inclined upwards from each side of the said axis,
and on the end of each of the said nearly horizontal levers or arms is a pin
projecting from each lever on opposite sides and upon each of the said pins is
mounted a roller.
Attached to the cross-head of the engine are two projecting arms or inclined
planes extending one in front of the said cross head and the other to the rear of it,
the said projecting arms or inclined planes are so disposed that one of them at the
end of the stroke of the piston comes in contact with one of the said rollers and
depresses its lever arm causing the lower lever arm to oscillate upon its axis and
to open one of the exhaust valves and close the other, and when the piston has
accomplished its stroke in the opposite direction, the second projecting arm or
inclined plane on the cross head comes in contact with the roller on the second
nearly horizontal lever, depresses the said lever, causing the lower lever arm to
oscillate in a contrary direction, thereby closing the exhaust valve that had been
open, and opening the other.-By this means, at each end of the stroke of the
piston, the exhaust valves are alternately opened and closed as required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Hoyois in the Great Seal Patent Office on the 21st November
1883.
ALFRED HOYOIS of Clabecq in the Kingdom of Belgium Civil Engineer
IMPROVEMENTS IN STEAM ENGINES
My invention relates to that class of steam engines in which there are two inlet
and two exhaust valves, the cylinder covers forming chambers through which the
steam is admitted to the engine, and it consists in the improvements hereinafter
described in the construction and arrangement of the inlet and exhaust valves and
in the means and devices or apparatus for operating the same.
In the inner side or end of each of the chambered cylinder covers is a central
circular hole or opening in which is fitted a metal tubular piece traversed by the
piston rod and forming with the said circular hole or opening an annular space or
port conducting from the said chambered cover into the cylinder.
Mounted on the outer surface of the said metal tubular piece is a cylindrical
valve pressed down upon its seat by two spiral or other suitable springs so as to
close the annular port herein before described, the said valve being raised or
opened when required by the operating mechanism hereinafter described. Each.
of the said valves is, by rods passing through the outer cylinder covers, connected
to the arms of a forked lever extending downwards from a horizontal longitudinal
bar capable of reciprocating motion in suitable bearings upon the top of the
cylinder, by causing either of the said bars to move outwards that is towards the
end of the cylinder, it will act upon the valve to which it is connected and open it
and steam will be admitted to one end of the cylinder.
The said bars receive motion to open the steam valves from an eccentric
mounted on the crank shaft of the engine, the end of the eccentric rod being
connected to the pin of a crank affixed upon a horizontal spindle suitably supported
and extending above and across the cylinder from the side to near its centre line
and having upon its other end a second crank, the pin of which extends across the
centre line of the cylinder and forms the axis of two L shaped pawls, the bori-
zontal arms of which project one towards each end of the cylinder and are formed
so as to be capable of engaging alternately with a catch formed on the inner end.
of each of the borizontal bars herein before described; the upper arms of the said
pawls are curved outwards and project upwards to between two stops carried by
and rising and falling with the governor according as the speed of the engine
increases or diminishes.
The action of the apparatus is as follows:
By the rotation of the crank shaft of the engine, the eccentric is caused to
impart an oscillating motion to the horizontal spindle above the cylinder and the
said spindle through the crank upon its inner end gives a reciprocating motion
to the two pawls upon its crank pin and the horizontal projecting arms of the said
pawls engage alternately with one or other of the longitudinal bars connected to
the steam valve and force it backwards, thus causing each of the steam valves to
open alternately and admit steam to each end of the cylinder. When the steam
valve operated upon has been opened to the required extent, the arm projecting
upwards from the pawl now engaged comes in contact with one of the stops
carried by the governor and is thereby arrested, causing the arm of the pawl now
engaged with the horizontal bar, to rise from the end of the said bar and release
the same,
the steam valve is then closed by the action of its springs and the steam
is cut off.
The continued rotatory motion of the crank shaft causes the eccentric to give
motion in a contrary direction to the pawls and the second pawl then engages
with the other horizontal bar and opens the other steam valve admitting steam>
to the other side of the piston and the steam valves are opened to a greater

page_text: .
or less extent according as the stops are raised more or less by the governor, the
curved vertical arms of the pawls coming sooner or later into contact with the said
stops according as the said stops are higher or lower for the time being
In order to prevent the injurious effects arising from too sudden changes in the
action of the governor, I arrange two blocks so that they act as a brake upon a
rotatory socket upon the governor spindle the pressure of the said blocks being
regulated by springs acted upon by suitable screws.
The exhaust ports of the engine are formed at the lower side of the cylinder
next to the chambered covers and the said exhaust ports are alternately closed and
opened by slide valves working in and out of chambers formed to receive them in
the lower part and within the ends of the cylinder, the said slide valves are
connected together by a rod formed so as to open one of the said ports and close
the other simultaneously. The said rod extends in front of the cylinder where it
is jointed to one end of a connecting rod, the other end of which is jointed to
the lower end of a lever forming part of a three armed lever mounted on an axis
perpendicular to the centre line of the cylinder and upon which it is capable of
oscillating, the other two arms of the said three armed lever project in a nearly
horizontal direction slightly inclined upwards from each side of the said axis and
on the end of each of the said nearly horizontal levers or arms is a pin projecting
from each lever on opposite sides and upon each of the said pins is mounted a
roller.
Attached to the cross-head of the engine are two projecting arms or inclined
planes extending one in front of the said cross-head and the other to the rear of it,
the said projecting arms or inclined planes are so disposed that one of them at the
end of the stroke of the piston comes in contact with one of the said rollers and
depresses its lever arm, causing the lower lever arm to oscillate upon its axis and
to open one of the exhaust valves and close the other-and when the piston has
accomplished its stroke in the opposite direction, the second projecting arm or
inclined plane in the cross head comes in contact with the roller on the second
nearly horizontal lever, depresses the said lever causing the lower lever arm to
oscillate in a contrary direction, thereby closing the exhaust valve that had been
open and opening the other-By this means at each end of the stroke of the
piston, the exhaust valves are alternately opened and closed as required. ⚫
But in order that my invention may be clearly understood I will proceed to
.describe with reference to the accompanying drawings means pursued by me in
carrying the same into effect.
Figure 1. represents in longitudinal section partly in elevation a steam cylinder
and parts connected therewith constructed according to my invention
Figure 2 is a horizontal section of part of Figure 1 showing one of the cylinder
covers forming a chamber through which steam is admitted into the cylinder and
the valve arrangement for the admission and cut off of the steam.
Figure 3 is a cross section of the cylinder taken through the line A. B. Figure 1.
Figure 4 is a cross section through the line C. D. Figure 1.
Figure 5 is a cross section through the line E. F. Figure 1, and Figure 6 is a
plan of the engine drawn to a smaller scale than figures 1. 2. 3. 4 and 5
The same letters and figures of reference are used to indicate like parts where
they occur in the different figures of the drawing.
a is the steam.cylinder which is supported on a suitable frame b-a¹ a² are the
two cylinder covers forming chambers through which the steam is admitted to the
cylinder a-c is the piston and c is the piston rod, d is the connecting rod,
the outer end of which is jointed to the crank pin e' of the crank e which crank e
is affixed upon the driving shaft e² (Figure 6). In the inner side or end of each of
the cylinder covers a', a² is a central circular hole or opening f in which is fitted a
metal tubular piece or valve seat 9 traversed by the piston rod c' and forming with
the hole or opening fan annular space or porti conducting from the chambered
cylinder covers into the cylinder a
Mounted on the outer surface of the tubular piece or valve seat g is a cylindrical

page_text: valvej pressed down upon its seat by two spiral springs l, so as to close the
annular port i the said valve j being raised to open the port when required by the
operating mechanism hereinafter described
Each of the said valves ; is by rods passing through the outer ends of the
cylinder covers connected to the arms m, m of a forked lever extending downwards
from a horizontal bar m' capable of reciprocating motion in bearings m³ upon the
top of the cylinder a, the projecting outer ends of the said bars being guided by
the tubular supports m³ or by any other suitable means
By causing either of the said bars m¹ to move outwards that is to say towards
its end of the cylinder a, it will, through its forked lever m acting upon the valve
rods and the valvej to which they are connected, open the said valve and steam
will be admitted to one end of the cylinder. The bars m' receive motion to open
the valves from an eccentric n mounted upon the main shaft e² of the engine.
n¹ is the eccentric rod, the end of which is connected to the pin o¹ of a crank o
affixed on one end of a horizontal spindle o² working in a sleeve os and extending
above and across the cylinder a from the side to near its centre line.-Upon the
other end of the spindle o³ is a crank of the pin o³ of which extends across the
central line of the cylinder a and forms the axis of two L shaped pawls p, q, the
horizontal arms p' q' of which pawls project one towards each end of the cylinder
and they are formed so as to be capable of engaging alternately with a catch formed
on the inner end of each of the horizontal bars m¹. The upper arms p² q² of.
the pawls p, q are curved outwards as shewn in Figure 1. and project upwards to
between two stops r, r¹ carried by and rising and falling with the governor rods 2
according as the speed of the engine increases or decreases.
The action of the apparatus is as follows:-
By the rotation of the crank shaft e² the eccentric n imparts an oscillating
motion to the crank o and spindle o² and the said spindle o' through the crank o'
gives a reciprocating motion to the two pawls p, q and the horizontal arms p', q¹ of
the said pawls engage alternately with one or other of the longitudinal bars m' and
force it to recede thus opening alternately the steam valves j and admitting steam
alternately to each end of the cylinder.
When the steam valve operated upon has been opened to the required extent
the vertical arm p² or q² of the pawl p or q then engaged, comes in contact with
one of the stops and its motion is thereby arrested, causing its horizontal arm
to rise from the end of the bar m' with which it is engaged and to release the said
bar. The steam valve j is then closed by the action of the springs 1, 1, and the
steam is cut off.
The continued rotatory motion of the crank shaft e² causes the eccentric to give
motion in a contrary direction to the pawls p, q and the second pawl then engages
with the other bar m' and opens the other steam valve, admitting steam to the
other side of the piston and the steam valves j are opened to a greater or less
extent according as the stops r. r¹ are raised more or less by the action of the
governor the curved vertical arms p², q² coming sooner or later into contact with
the said stops according as the said stops are higher or lower for the time being
In order to prevent the injurious effects arising from too sudden changes in
the action of the governor I place round the governor sleeve 1 two small
cataracts 2.
The exhaust ports of the engine are formed at the lower part of the cylinder
at s next to the chambered covers and the said exhaust ports open into the
channel t and are alternately closed and opened by slide valves &' one of which is
represented in figure 1. The said slide valves work in and out of chambers formed
to receive them in the lower part and ends of the cylinder. The said slide valves
are connected together by arms s² on a rod t which rod extends longitudinally
throughout the channel t and passes on to the outside where it is jointed to one
end of a connecting rod t the other end of which connecting rod is jointed to the
lever u forming part of a three armed lever mounted upon an axis n' upon which
it is capable of oscillating, the other arms u³ and us of the said three armed lever

page_text: "
project in a nearly horizontal direction slightly inclined upwards from the sides of
the axis u¹ and on the end of each of the arms, u², u³ is a pin v, v¹ projecting
therefrom, the pin projecting from one side of the lever n³ and the pin
projecting from the opposite side of the lever u³. Upon each of the said pins v, vl
is mounted a roller v³ and v³ respectively Underneath the cross head w of the
engine are two projections forming inclined planes w¹ and w² the former w¹ being
situated at the rear end of the said cross head and the latter w² at the front part
of it.
The said projections or inclined planes w¹ and w² are disposed so that at the
end of the stroke of the piston outwards the inclined plane w¹ comes in contact
with the roller v³ on the end of the lever arm u³ and depresses the said lever arm
causing the lower lever arm u to oscillate upon its axis u¹ and to push the
connecting rod t and the valve rod t backwards, thus opening the exhaust port at
the rear end of the cylinder and closing the valve s¹ at the front end of it, and when
the piston has accomplished its stroke in the opposite direction, the inclined
plane w comes in contact with the roller 2 on the lever arm u³, depresses the said
lever arm u² causing the lower arm u to oscillate in a contrary direction and
through the connecting rod t to draw forwards the valve rod t¹ and cause
the exhaust valve s¹ to open and the valve at the rear end of the cylinder
to close.
Having thus described the nature of my said invention and in what manner the
same is to be performed, I would wish it to be understood that I do not confine
myself to the precise details herein-before described and illustrated in the
accompanying drawings, as the same may be varied without departing from the
nature of my invention:
But I claim as my invention of improvements in steam engines,
Firstly. The arrangement and combination of parts of steam engines substan-
tially as herein-before described and illustrated in the accompanying drawings.
Secondly. In steam engines wherein the steam is admitted to the cylinder
through chambered covers, the devices for opening and closing the steam valves
and effecting the cut off of the steam that is to say by means of two L shaped
pawls to which reciprocating motion is given from an eccentric, the said pawls
acting alternately on suitable rods and levers attached to the steam valves so as to
open them alternately as required, the extent of the opening of the said valves
being controlled by the action of the governor on the vertical arms of the said
pawls and the cut off of the steam being effected by suitable springs substantially
as herein before described and illustrated in the accompanying drawings.
Thirdly. The devices for actuating the exhaust valves that is to say by means
of a three armed oscillating lever the upper arms of which are alternately
depressed by inclined planes formed on the underside of the crosshead, thereby
causing the said lever to oscillate upon its axis and by its lower arm acting on
suitable rods, to open and close the exhaust valves alternately each time that the
piston is at the end of its stroke
Fourthly. The construction and arrangement of the steam cylinder by which
the exhaust slide valves work in chambers formed to receive them in the ends of
the cylinder and within the said cylinder just under the chambered covers,
substantially as described.
In witness whereof I the said Alfred Hoyois have hereunto set my hand and
seal this Seventeenth day of November in the year of Our Lord One thousand
eight hundred and eighty three.