CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to Edward Wood, of the Firm of J. and E. Wood, of the
Victoria Foundry, Bolton, in the County of Lancaster, Engineer, for the
Invention of "CERTAIN IMPROVEMENTS IN STEAM ENGINES."
Sealed the 6th July 1877, and dated the 24th February 1877.
PROVISIONAL SPECIFICATION left by the said Edward Wood at the Office
of the Commissioners of Patents on the 24th February 1877.
EDWARD WOOD, of the Firm of J. and E. Wood, of the Victoria Foundry, Bolton,
in the County of Lancaster, Engineer.
"CERTAIN IMPROVEMENTS IN STEAM
ENGINES."
My Invention is applicable to those compound steam engines in which the pistons
of the bigh-pressure cylinder and of the low-pressure cylinder are attached to the same
piston rod, and in which Corliss or other description of valves are attached to the
lower sides of the high and low pressure cylinders, and it consists of an improved
mode of connecting the cylinder further from the crank shaft, and which I prefer
to make the low-pressure cylinder, to the main framing of the engine.
The main framing consists of the ordinary cast-iron structure supporting the
bearing of the crank shaft and the slides for the cross head, to which is also cast a
target end, to which the cylinder nearer to the crank shaft is bolted. The target
end is also provided with bosses, or other suitable preparations for receiving the
ends of two or more side stay rods, or other connecting framework, the other ends
of which are connected to the other cylinder. By connecting the cylinder nearer
to the crank shaft direct to the target end of the main framing, the stay rods can pass
direct on each side of this cylinder, without being connected to it, to the cylinder
further from the crank shaft. By this arrangement the expansion and contraction
of one cylinder does not affect the other cylinder.
Another part of my Invention relates to the valves of compound steam engines.
In a compound "tandem" steam engine in which "Corliss" valves are used in both
the high and low pressure cylinders, I use the same arrangement of parts for
actuating the steam valves of the low-pressure cylinder as described in the Speci;
fication of former Letters Patent, granted to me on the 23rd day of February, 1876,
ID 27

page_text: Number 749, with this exception, that the double wedge for disengaging the valves,
which was there described as being raised and lowered by the governor, is held in
one fixed position. I also connect the driving gear of the steam valves of both the
high and low pressure cylinders, to one and the same driving eccentric; I also
connect the valve levers of all the exhaust valves of both the high and low
pressure cylinders by one continuous coupling rod, carrying suitable bearings for the
pins of the valve levers. I use one eccentric for driving all the exhaust valves or
both cylinders together, and I connect the rod from this eccentric to the continuous
coupling rod before mentioned. The levers of the exhaust valves are all of an equal
length, and have the same throw, thus allowing the continuous coupling rod to be
made in one rigid piece.
Another part of my Invention relates to the cut-off motion of steam engines, and
it consists in an improved combination of machinery for actuating equilibrium,
Cornish, stamper, or other valves. The governor is connected to an elbow lever
jointed to a toothed bar hinged to the lower end of the tappit rod. The short arm
of this elbow lever is acted upon by the cam for raising the tappit rod. The cam
acts on a toothed sliding block.
When the engine is at work, the toothed sliding block is raised by the cam, and
drops by gravity or by a spring. When the block is down, the toothed bar falls into
gear with it by gravity or by a spring, and as the toothed block rises it imparts the
same motion to the tappit rod, thus opening the valve. When the engine is
running too fast, the governor brings the short arm of the elbow lever sooner in
contact with the cam, consequently the cam in revolving disengages the toothed bar
from the sliding block, and allows the valve to drop carlier than when the engine is
running its proper speed. The contrary action takes place when the engine is
running too slow.
The elbow lever is provided with a third arm, which when the governor stops
revolving, comes in contact with a stud to disconnect the toothed bar from the
sliding block, thereby preventing them again coming into gear, and allowing the
valve to remain closed.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Wood in the Great Seal Patent Office on the 13th July
1877.
EDWARD WOOD, of the Firm of J. and E. Wood, of the Victoria Foundry, Bolton,
in the County of Lancaster, Engineer. "CERTAIN IMPROVEMENTS IN STEAM
ENGINES."
My Invention is applicable to "tandem" compound steam engines, in which the
pistons of the high-pressure cylinder, and of the low-pressure cylinder, are attached
to the same piston rod, as shewn in Fig. 1 of the accompanying Sheet of Drawings,
and it consists in an improved mode of connecting the cylinder further from the
crank shaft, and which I prefer to make the low-pressure cylinder, to the main
framing of the engine.
The main framing consists of the ordinary cast-iron structure a, supporting the
bearing of the crank shaft b, and the slides for the cross head, and to which is also
cast the target end c, to which the high-pressure cylinder d, nearer to the crank
shaft, is bolted. The target end c is also provided with bosses c¹ or other suitable
preparations for receiving the ends of two or more side stay rods e, or other con-
necting framework, the other ends of which are connected to the low-pressure
cylinder f. By connecting the cylinder nearer to the crank shaft direct to the
target end of the main framing, the stay rods can pass direct on each side of this
cylinder, without being connected to it, to the cylinder the further from the crank

page_text: shaft. By this arrangement the expansion and contraction of one cylinder does not
affect the other cylinder.
Where Corliss valves are used, I also connect the valve levers of all the exhaust
valves 9, of both the high and low pressure cylinders, by one continuous coupling
rod carrying suitable bearings for the pins of the valve, levers. I use one
eccentric b¹ for driving all the exhaust valves of both cylinders together, and I
connect the rod from this eccentric to the lever i, to which the end of the con-
tinuous coupling rod h is jointed. The levers of the exhaust valves are all of an
equal length, and have the same throw, thus allowing the continuous coupling rod h
to be made in one continuous rigid piece. Instead of the lever i, a slide or other
means for supporting the eccentric rod may be adopted.
The driving gear of the steam admission valves, of both the high and low
pressure cylinders, is also connected to one and the same driving eccentric.
Another part of my Invention relates to the valve gear of compound steam
engines. In a compound steam engine, in which "Corliss" valves are used in both
the high and low pressure cylinders, I use the same arrangement of parts for actuating
the steam valves of the low-pressure cylinder as that described in the Specification of
former Letters Patent, granted to me on the 23rd day of February 1876, Number
749, with this exception, that the double wedge, inarked o in the said Specification,
for disengaging the valves, which was there described as being raised and lowered
by the governor, and as being carried upon cranked studs p¹, is now replaced by
two single wedges, which are stationary, and not influenced by the governor.
may also apply any other arrangement of Corliss valve gear in which the admission
valves are closed by springs, and in which the cut off is not influenced by the
governor in lieu of the above.
I
Another part of my Invention relates to the cut-off motion of steam engines, and
it consists in an improved combination of machinery for actuating equilibrium,
Cornish, stamper, or other valves, as shewn in Figs. 3 and 4. The governor is con-
nected to the elbow lever j, jointed to the toothed bar, hinged to the lower end of
the rod l, which is connected to the valve. The short arm of this elbow lever is
provided with an antifriction bowl, which is acted upon by the cam m, which at
the same time serves for moving the rod l. The cam acts on a toothed sliding
block n.
When the engine is at work, the toothed sliding block is raised by the
cam, and drops by gravity or by a spring. When the block is down, the toothed
bar / falls into gear with it by gravity or by a spring, and as the toothed block
rises it imparts the same motion to the rod 1, thus opening the valve. When the
engine is running too fast, the governor brings the short arm of the elbow lever j
nearer to the cam m, consequently the cam in revolving disengages the toothed bar
k from the sliding block n, and allows the valve to drop earlier than when the
engine is running its proper speed. The contrary action takes place when the
engine is running too slow. The elbow lever j is provided. with a third arm j³,
which, when the governor stops revolving, comes in contact with a stud o to
disconnect the toothed bar from the sliding block, thereby preventing them again
coming into gear, and allowing the valve to remain closed.
Having thus stated the nature and particulars of my Invention, I declare that I
claim,―
First. The improved mode of connecting the cylinders of "tandem" compound
steam engines, as shewn and described in reference to Figs. 1 and 2.
Secondly. Connecting the exhaust valves of the high and low pressure cylinders
of "tandem" compound steam engines to one continuous coupling rod and one
eccentric, as shewn and described.
Thirdly. The application of the arrangement of parts, described in the Specifica-
tion of former Letters Patent, granted to me on the 23rd day of February 1876,
Number 749, for actuating the valves of high-pressure cylinders to actuate the valves
of the low-pressure cylinders of compound steam engines with the modifications
described.

page_text: Fourthly. The application of two single wedges in lieu of the double wedge
described in the Specification above referred to.
And, Lastly. The improved cut-off motion for steam engines, as shewn and
described in reference to Figs. 3 and 4.
In witness whereof, I, the said Edward Wood, have hereunto set my hand
and seal, this Ninth day of July, One thousand eight hundred and seventy-
seven
EDWARD WOOD. (LS)