IMPROVEMENTS IN STEAM ENGINES
Year: 1879

page_text: LETTERS PATENT to David Joy, of Barrow-in-Furness, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
Sealed the 10th June 1879, and dated the 8th March 1879.
PROVISIONAL SPECIFICATION left by the said David Joy at the Office of
the Commissioners of Patents on the 8th March 1879.
DAVID JOY, of Barrow in Furness, in the County of Lancaster, Engineer.
PROVEMENTS IN STEAM ENGINES."
"IM-
My Invention relates to improvements in steam engines of what are known as
the compound type, using high pressure in a first cylinder and expanding it in a
second or more, the high and low pressure cylinders being placed side by side as
close together as possible; and it has for its object the simplifying of the arrrange-
ment of such engines to render them more generally applicable.
The improvements consist, firstly, in transmitting the force from the crosshead
with which the piston rod from each cylinder is connected to the crank by a frame
rather than a connecting rod in the ordinary sense of the term, this frame taking
its bearing on the whole or nearly the whole width of the crosshead, and acting
with a similar extent of bearing on a long crank pin, which by preference has a
crank and fixed bearing at each side, so that practically the strain from each piston
is transferred to each crank, and thus blended and equalized on the shaft.
For direct acting pumps also I place the high and low pressure cylinders close
together and couple their piston rods together, either connecting them each to a
pump, or connecting one pump between them. Secondly. In the application and
use of a simple form of valve gear capable of giving expansive action or reversal to
the valve or valves. It consists of a double lever, the longer end of which is
attached to any point of the connecting rod; the fulcrum of this lever instead of
being fixed traverses a slide which is centered at right angles, or nearly so, to the
line of motion of the connecting rod. This slide is capable of being angled to either
side of the right angle; to the outer and shorter end of the said lever is attached
the rod actuating the valve. Instead of a slide a combination of levers and rods
may be employed to carry the fulcrum of the lever above described, such parallel
motion being hung on a frame centered in the same manner as the slide; or the
5

page_text: centre of the lever may be hung on a link centering at or about the position of the
valve spindle joint.
Thus it will be seen that the valve being moved first by a lever attached to the
connecting rod is partaking of the movement of the crank, but this motion is
modified by the movement of the fulcrum of the lever in the slide according to the
angle at which that slide is set, and by a combination of these two movements in
various proportions all the positions required for various degrees of cut-off and of
reversal may be obtained. This motion from its simplicity may be applied to any
class of engine, whether stationary, marine, or locomotive. The slight inequality in
the motion of the valve arising from the arc of the lever may be corrected by
attaching the end of the lever (described above as attached to the connecting rod),
not directly to the connecting rod but part way along another lever, the one end of
which is attached to the connecting rod, the other end sliding in a guide on the
opposite side, and at right angles to the motion of the connecting rod. The arcs
made by these two levers crossing will correct each other and produce a perfectly
equal action. By varying the proportion of the levers and the slide action, and so
varying the proportion of motion transmitted to the valve by each, any combina-
tion of port and lead may be obtained.
An additional cut-off valve may be employed by using a second lever and setting
the slide in which its fulcrum moves at the reverse angle to the main slide. By
this a very sharp cut off is obtained.
To apply this motion for working the valves of direct acting pumps or engines
where there is no rotatory motion a slight modification is required. In this case
the lever actuated by the connecting rod in the rotating engine is attached to the
crosshead of the piston rod and has its fulcrum carried in a slide as before, but the
angle of the slide is changed over from side to side either by mechanical action, as
by the changing of the motion of the rod bringing a thrust on the slide and throwing
it over, or by a small cylinder and piston connected to it, this small cylinder
receiving steam from the large cylinder. Thus at each end of the stroke the steam
admitted at lead to the large cylinder passes over to the small cylinder and reverses
the position of the angled slide, or the small cylinder may have a special valve. The
speed of the small cylinder may be controlled by a cataract cylinder, or it may itself
be made to constitute a cataract cylinder by arranging that the steam pressure
shall act on the surface of two reservoirs of fluid, one for each end of the small
cylinder, which shall transmit the pressure to the piston under control of checking
valve. This action may also be used for rotating engines by coupling the lever end
to the crosshead instead of to the connecting rod.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said David Joy in the Great Seal Patent Office on the 8th September
1879.
DAVID JOY, of Barrow-in-Furness, in the County of Lancaster, Engineer. “Iм-
PROVEMENTS IN STEAM ENGINES,"
My Invention relates to improvements in steam engines of what are known as
the compound type, using high pressure in a first cylinder and expanding it in a
second or more, the high and low pressure cylinders being placed side by side as
close together as possible; and it has for its object the simplyfying of the arrange-
ment of such engines to render them more generally applicable.
The improvements consist, firstly, in transmitting, the force from the cross-head
with which the piston rod from each cylinder is connected to the crank by a frame
rather than a connecting rod in the ordinary sense of the term, this frame taking
its bearing on the whole or nearly the whole width of the crosshead, and acting.
with a similar extent of bearing on a long crank pin, which I find it advantageous
to make with a crank and fixed bearing at each side, so that practically the strain
from each piston is transferred to each crank, and thus blended and equalized on
the shaft. For direct acting pumps also I place the high and low pressure cylinders
close together and couple their piston rods together, either combining them each
to a pump, or connecting one pump between them. By means of this arrangement
I effect great economy in expense of manufacture compared with that- hitherto
incurred in making such engines with double connecting rods, as has been usual
heretofore.
Secondly. In the application and use of a simple form of valve gear constructed
substantially as hereinafter described and shewn in the Drawings, capable of giving
expansive action or reversal to the valve or valves; it consists of a double lever,
the longer end of which is attached to any point of the connecting rod; the fulcrum
of this lever, instead of being fixed traverses a slide which is centred at right angles or
nearly so to the line of motion of the connecting rod; this slide is capable of being
angled to either side of the right angle; to the outer and shorter end of the said
lever is attached the rod actuating the valve. Instead of a slide a combination of
levers and rods may be employed to carry the fulcrum of the lever above described,
such parallel motion being hung on a frame centred in the same manner as the
slide, or the centre of the lever may be hung ou a link centering at or about the
position of the valve spindle joint. This is an arrangement which I do not recommend
to be employed, as slide action above referred is much better in practise.
Thus it will be seen that the valve being moved first by a lever attached to the
connecting rod is partaking of the movement of the crank, but this motion is
modified by the movement of the fulcrum of the lever in the slide, according to the
angle at which that slide is set, and by a combination of their movements in
various proportions, all the positions required for various degrees of cut-off and of
reversal may be obtained.
This motion from its simplicity may be applied to any class of engine, whether
stationary, marine, or locomotive, the slight inequality in the motion of the valve
arising from the arc of the lever may be corrected by attaching the end of the
lever (described above as attached to the connecting rod) not directly to the con-
necting rod but part way along another lever, the one end of which is attached to
the connecting rod, the other end sliding in a guide on the opposite side and at
right angles to the motion of the connecting rod; the ares made by these two levers
crossing will correct each other and produce a perfectly equal action. By varying
the proportion of the levers and the slide action, and by varying the proportion of
motion transmitted to the valve by each, any combination of lap and lead may be
obtained.

page_text: To apply this motion for working the valves of direct acting pumps or engines
where there is no rotatory motion a slight modification is required. In this case
the lever actuated by the connecting rod in the rotating engine is attached to the
crosshead of the piston rod, and has its fulcrum carried in a slide as before, but the
angle of the slide is changed over from side to side either by mechanical action, as
by the changing of the motion of the rod bringing a thrust on the slide and
throwing it over, or by a small cylinder and piston connected to it, this small
cylinder receiving steam from the large cylinder; thus at each end of the stroke
the steam admitted at lead to the large cylinder passes over to the small cylinder
and reverses the position of the angled slide, or the small cylinder may have a
special valve; the speed of the small cylinder may be controlled by a cataract
cylinder, or it may itself be made to constitute a cataract cylinder by arranging
that the steam pressure shall act on the surface of two reservoirs of fluid, one for
each end of the small cylinder, which shall transmit the pressure to the piston
under the control of a checking valve.
And my Invention will be clearly understood by reference to the accompanying
Drawings, in which Sheet 1, Figs. 1 and 2, represent a horizontal engine arranged
according to my improvements. Here the high and low pressure cylinders being
placed alongside of each other, and their piston rods connected to one crosshead,
the force is thence transmitted by a connecting frame a, a, (in lieu of the usual
connecting rod) from the whole length of the cross head to the whole length of the
crank pin, thereby as far as possible preventing cross strains on the working parts,
as must be the case where only an ordinary single connecting rod is employed.
The same arrangement is also applied to pumping engines, as shown on Sheet
No. 1, Fig. 3, where the high and low pressure pistons are connected each to a
distinct pump but coupled together by one crosshead; or they may be coupled
together and connected to a single pump.
For these and other engines I employ a simple form of valve motion capable of
reversing and giving expansive action to the valve or valves without the employ-
ment of eccentrics.
Figure 1, Sheet 2, illustrates this valve motion in its simplest and most perfect
form as applied to an ordinary overhead marine engine.
In this valve gear, bearing in mind that the motion required to actuate a slide
valve with lap requires an eccentric to be set about halfway between the position
of the crank when at the end of the stroke, and its position at half stroke, and is
therefore a movement timed between those two. The motion for the valve is
taken from the connecting rod by utilizing both its vertical and its horizontal
movement, and by combining these two movements a motion is obtained similar to
that of an eccentric set as described.
Referring now to the Drawing a lever a is centred at a¹ in a block free to slide
in a curved slot link b, which is centred at 61 and free to be set at various angles
to the horizontal. This lever a receives motion from the connecting rod through a
second lever or rod c pinned to the connecting rod at a convenient point on its
centre line, up or down, or away from it on either side, according to the position
and amount of movement required; or this action may be taken direct from the
crank. This rod c at the other end is either allowed to slide horizontally in a
block and slide, as shown in Fig. 2, or it is suspended by a suspending link, as
shewn in Fig. 1, and thus vibrates in a cross direction to the vibration of the
connecting rod. The point a² at which the end of the lever a is jointed to this rod
or lever c is such as to correct the radial error of the lever a, and to cause its
fulcrum to traverse the slot link b equally on each side of its centre, but while
correcting this action it does not reduce its amount. The lever a will therefore
have imparted to it at the point a² a vertical action, while its fulcrum will also be
traversed horizontally and equally in the slot link b, partaking also of a motion
due to the angle at which the slot link may be set. The outer end of this lever a³,
to which the valve rod e is attached, will therefore have a movement compounded

page_text: of the up and down lever action of the lever a, and of a similar motion, but timed
differently, caused by the fulcrum sliding in the slot link b; and in proportion to
the predominance of either of these movements any lap, lead, or port, and any
point of cut-off may be arranged for. It is evident that when the slot link 6 is in
the horizontal position the valve will be moved only for "mid gear," and in pro-
portion as it is varied from this position either way forward or backward motion
will be given to the valves with an opening of the ports of more or less duration
and extent, according to the angle of the slot link. Thus with an action taken
from the connecting rod movement is communicated direct to the valve, the radial
action of the lever a being corrected by the rod c, and the radial action of the
valve connecting link e being corrected by the curvature of the slot link b, resulting
thus in a correct action of the valve, giving equal leads, points of cut-off, and
openings of port for both ends of the cylinder, each of which however may be
varied at pleasure either way by altering the proportions of the parts and the point
at which the centre of the lever a crosses the centre of the slot link b. Instead of
the centre of the lever a sliding in the slot link it may be hung by a suspending
link, the upper end of which is centred at such a distance and position as to cause
the centre of the lever a to traverse a similar path to what it would if governed
by the slot link, the point of suspension of such suspending link being adjustable
so as to allow of the curves formed by its vibrating end to be the same as the curves
of the slotted link in its various positions or angles.
To work a cut-off valve on the back of the main valve, as is customary with an
extra eccentric when the link motion is employed, an additional lever like a and
a slot link like b may be employed, the slot link of the expansion valve being set
at the reverse angle to that of the main slide valve, and being more or less angled
according to the amount of expansion required. Or the lever a may be lengthened
at its outer end, see Sheet No. 2, Fig. 1, and the expansion or cut off valve rod f
may be attached to this with an adjustment for lengthening or shortening the
stroke, according to the expansion required, as shewn in the Drawing.
This gear, which is specially adapted for actuating slide valves under high
pressure steam and the large and heavy valves of marine engines, which have a
long stroke or traverse, all of which require great force to move them, is suitable
to all engines requiring reversal and expansive motion, such as is now usually
gained by the "link motion," and modification of the parts will render it available
wherever the "link motion" obtains. Thus, for locomotives, rolling mill, and
winding engines, for agricultural and traction engines where the diameter of the
cylinder bears a small proportion to the length of the stroke, I connect the rod c to
a point considerably outside the centre line of the connecting rod, as shown in
Fig. 1, Sheet 3, and thus I bring the centre line of the valve spindle into suitable
relation to the centre of the cylinder, whilst I also obtain an increased duration of
the maximum opening of the port towards the end of its movement. In Fig. 2,
same Sheet, is shown a half cross section of the same engine.
Retaining the general principles of this gear its arrangement may be modified as
in Fig. 1, Sheet 4, where the lever a is pinned directly to the connecting rod, a
straight slot link b is used, and the errors arising from such changes are balanced
against each other by setting the centre of support 6¹ on which the slot link is
angled out of the centre line of the slot link as shewn; or the corrections of the
radial action of the lever a, and of the valve rod e may be effected by carrying the
centre of the slot link b in a horizontal slide, and moving it backwards and
forwards each stroke by the amount of the above named radial errors.
And again as in Fig. 2, Sheet 4, the lever a may be exchanged for a bell crank
lever and a connecting link a³; the action of this bell crank at each change of
motion of the connecting rod being controlled by a cataract cylinder, or by a spring
as shewn in the Drawing.
Or again as in Fig. 3, Sheet 4, the centre of the lever a or of the bell crank a³.
°

page_text: may be stationary in the slot link (its position therein governing the forward or
backward motion, and the amount of expansion), and its inner end. receives one
motion from the connecting rod, while the other motion is supplied by the slot link
itself being vibrated by its attachment to the cross head or connecting rod; or the
slot link may be a part of or may be fixed to the usual air pump levers, which
already have the required motion from the crosshead; or if in any instance it is
found convenient to attach the valve rod within the fulcrum of the lever, as shown
in dotted lines Fig. 3, then as the action communicated to an ordinary slide valve
would be exactly opposite to that required, I employ in such case a double D valve
admitting the steam past the lip of the port face at m, as shown at Fig. 4, same
Sheet, instead of the usual slide valve.
The application of the main features of this valve gear to direct acting pumping
engines is shown on Sheet 1 at Fig. 3; here the lever a receives motion from the
cross head, both as a lever, and as sliding its fulcruin in the slot link b, but as both
the inward and outward strokes of the crosshead are similar it is necessary to
change the angle of the slot link for each opposite stroke. This is done by a small
steam or water cylinder at z controlled by a cataract cylinder, which may be one
with it as shown; or the steam cylinder may be made to serve both purposes by
making its ports of such capacity that they will contain sufficient water or fluid to fill
the cylinder at each stroke, that it would then nearly pass backwards and forwards
between the cylinder and ports. The piston rod of this small cylinder is connected
to either end of the slot link, as is convenient, and the steam may be admitted to it
either by the main valve or by a small independent valve; or the slot link may be
pushed over by the thrust of the lever a on its return movement at each end of the
stroke of the piston; a suitable locking catch being provided to hold it over till the
opposite end stroke is required, when the position of the lever a unlocking this
catch and reversing its pressure on the slot link would again push it over to its
other position.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the manner in which it may be used or carried into effect, I would observe
in conclusion that,-
1st. I do not claim making compound engines with their cylinders placed side
by side, and their pistons coupled to one crosshead, but I claim the use of my
improved arrangenients of parts forming a connecting frame, by means of which a
proper distribution of strain is effected, substantially as herein before described
and illustrated by Figures 1 and 2, Sheet I of the accompanying Drawings.
2. I do not claim generally taking movement for the slide valves of steam
engines from the connecting rod, nor do I claim the use for that object of a lever
pinned to a connecting rod, but I claim the use for the purposes herein before
mentioned of a lever coupled and having its motion governed in the manner
described in my Specification, the lever being so arranged in connexion with the
parts combined therewith that the required corrected action is transmitted, so as to
work the valve easily and accurately with the requisite regulated motion,
substantially as hereinbefore described and illustrated by Sheets 2, 3, and 4 of
the accompanying Drawings.
3. The use for the purposes herein before mentioned of my improved apparatus
when modified in the manner illustrated in the various modifications, substantially
as herein before described, and as shown in Sheet 4 of the accompanying
Drawings.
4. The application of valve gear such as is herein before described and claimed to
all engines, where hitherto the "link" motion has served like purposes, substantially
as herein before described.
5. The application of my improved gear in the modified form suitable for
actuating the valves of pumping engines, substantially as herein before described and
illustrated by Sheet 1 of the accompanying Drawings.
°

page_text: 6. Actuating a cut off or expansion valve either by a separate set of such gear or
by an adjustable attachment to the lever working the ordinary valve, substantially
as herein described.
In witness whereof, I, the said David Joy, have hereunto set my hand and
seal, this Third day of September, in the year of our Lord One thousand
eight hundred and seventy nine.
DAVID JOY. (L.S.)