Improvements in the Construction of Duplex Engines.
Year: 1891

page_text: Date of Application, 28th May, 1891
Complete Specification Left. 7th July, 1891-Accepted, 8th Aug., 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by CHARLES CAMPBELL WORTHINGTON, of
Irvington, West Chester County, in the State of New York, United
States of America, Mechanical Engineer.]
Improvements in the Construction of Duplex Engines.
I, PHILIP ARTHUR NEWTON of the Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of Middlesex, Patent Agent, do hereby declare the
nature of this invention to be as follows:-
This invention relates to duplex engines, its object being to provide an improved
valve movement, in which fewer parts are exposed, and which shall be simpler,
cheaper, and require less oiling than valve movements heretofore in use.
In duplex engines as commonly constructed, the cross motion for operating the
valve of one side of the engine from the other side, has been placed outside the
steam chest, between the piston rods and valve rods, and on account of the necessity
of reversing the movement of one of the valves from that of its actuating piston
rod, operating levers of different form have been required, involving the con-
struction of several parts of different dimensions. The mechanism of the cross
notion also being outside the steam chest, is exposed to accident, and each moving
part requires to be oiled separately.
In those constructions in which the cross motion has not been placed between the
piston rods and valve rods, the operation of the valve on one side of the engine
from the other side has been attained either by cross ports in. the valve chest, or,
where attained by means of mechanical cross motion devices between the valve
rods and valves, the valves or ports on one side of the engine have been arranged
to secure the reversal of the movement of one of the valves relatively to its
actuating piston rod, necessitating the use of different forms of valves, or different
arrangements of steam ports, on the opposite sides of the engine.
To avoid these objections, it is now proposed to operate cach valve rod by its
own piston, and thereby to employ fewer parts, and these of simpler construction,
the cross motion for transmitting the motion of the valve rod of one cylinder to the
valve of the other cylinder, being placed inside the steam chest.
To explain the nature of the invention, it will suffice to describe the manner of
applying it to a simple duplex engine, the cylinders of which I will designate A.
and B.
Situate above the cylinder A, and parallel with its piston rod, is a valve rod which
is connected to its piston rod, externally of the steam jacket, by a rock lever mounted
on a fixed fulcrum.
This valve rod is fitted with an adjustable rigid arm, which stands out at right
angles to the rod, and overlies the slide valve of the cylinder B, which valve is
provided at its back with adjustable tappets.
It is into the space between the tappets, that the end of the arm enters, and thus,
at every movement of the piston rod of the cylinder A, the valve rod is caused
to shift the valves of the cylinder B, by its arm.striking against one or other of the
tappets.
In like manner, the valve rod of the cylinder B is connected by a rock lever
working on a fixed fulcrum outside the steam jacket, for operating the valve of the
cylinder A.
Instead, however, of this rod being fitted with a rigid arm, it is provided with
adjustable tappets for actuating a transverse rock lever carried by a fulcrum within
the steam jacket. The other end of this rock lever enters a space between two
tappets on the back of the slide valve of the cylinder A.

page_text: The motion, therefore, of the piston rod of the cylinder B, will impart, through
the valve rod connected therewith, motion to the rock lever which engages with
the tappets on the valve of the cylinder A, and thus the valve will be shifted at the
completion of a stroke.
An obvious modification of this arrangement is, to fit the piston rods with
tappet arms which are made to engage with adjustable lugs on the corresponding
valve rods.
By the above described arrangement of parts, the cross motion will be constantly
lubricated by steam and oil from the ordinary steam pipe lubricator,-thus avoiding
the, necessity for other lubrication.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Construction of Duplex Engines.
I PHILIP ARTHUR NEWTON of the Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of Middlesex, Patent Agent, 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 relates to duplex engines, its object being to provide an improved
valve movement in which fewer parts are exposed than in valve movements
heretofore in use; which, moreover, shall be simpler and cheaper in construction,
and require less oiling.
*In duplex engines as commonly constructed, the cross motion for operating the
valve of one side of the engine from the other side, has been placed outside the
steam chest between the piston rods and valve rods, and on account of the necessity
of reversing the movement of one of the valves from that of its actuating piston
rod, operating levers of different form have been required, involving the con-
struction of several parts of different dimensions. The mechanism of the cross
motion also being outside the steam chest, is exposed to accident, and each moving
part requires to be oiled separately.
In those constructions in which the cross motion has not been placed between the
piston rods and valve rods, the operation of the valve on one side of the engine
from the other side, has been attained either by cross ports in the valve chest,
or, where attained by means of mechanical cross motion devices between .the
valve rods and valves, the valves or ports on one side of the engine have been
arranged to secure the reversal of the movement of one of the valves relatively
to its actuating piston rod, necessitating the use of different forms of valves, or
different arrangements of steam ports on the opposite sides of the engine.
To avoid these objections, it is now proposed to operate each valve rod by its
own piston, and thereby to employ fewer parts, and these of simpler construction,
the cross motion for transmitting the motion of the valve of one cylinder to the
valve of the other cylinder being placed inside the steam chest, the moving
parts of the cross motion thus being constantly lubricated by steam and oil from
the ordinary steam pipe lubricator, avoiding all other oiling. In that form of the
duplex engine in which the tappet movement is not employed, the lost motion is
inside the steam chest, but in that form which employs the tappet movement, the
·lost motion is placed outside of the steam chest, and thus the engine is caused to
make a full stroke by moving the opposite valve only at the time when the
operating piston has nearly accomplished its stroke.
For a full understanding of the invention, a detailed description of an engine
embodying the same will now be given, reference being had to the accompanying
drawings forming a part of this Specification, in which
Fig. 1 is a sectional plan of a duplex engine arranged according to this
invention.

page_text: Fig. 2 is a longitudinal section taken through one of the steam cylinders.
Fig. 3 is a cross section on the line 3-3 of Fig. 1.
Fig. 4 is a sectional plan of a duplex engine employing a tappet movement; and
Fig. 5 is a longitudinal sectional elevation of the same, the section being taken
through one of the steam cylinders.
Referring now to said drawings, A, B, are a pair of steam cylinders, provided
with the usual introduction and exhaust ports a b, the induction ports com-
municating with the steam chest C, and the exhaust ports with the exhaust
pipes D, E, controlled by the sliding D-valves FG, as is usual in this class of
construction. HI are the piston rods of the respective cylinders, and KL the
corresponding valve rods, these valve rods being operated from the piston rods on
their own side of the engine by means of levers M N of the first class, pivoted at c,
and engaging the respective piston rods by means of the usual adjustable collars d,
the levers and connections on opposite sides of the engine being identical in
construction.
Inside the steam chest C, is adjustably secured to the valve rod K, an arm 0,
extending across the steam chamber, and engaging the slide valve G by means of
lugs thereon, a certain amount of lost motion being allowed to the arm O between
the lugs. The valve rod L carries lugs engaging one end of a lever I mounted
on a pivot g, central to the valve chest, this lever P extending across the chest, and
engaging the slide valve F by means of lugs carried thereby,-lost motion being
provided between the lugs and lever preferably at both ends of the latter, the
lugs being preferably made adjustable as shown.
It will readily be understood that the movement of the piston rods on each side
of the engine operates the valve rods on the same side, and that the valve rod K,
near the end of one stroke, moves the slide valve G in the same direction as the
valve rod, and opposite to that of the piston rod H. on the same side of the engine,
and the valve rod L, near the end of its stroke, moves the slide valve F in a
direction opposite to that of the valve rod, and the same as that of the piston rod I,
the direction of movement of the valve rod and valve being reversed by means of
the lever P.
The construction shown in Figs. 4 and 5 is the same, except that the valve rods
are operated by means of tappets R S carried by the piston rods, and engaging
adjustable lugs on the corresponding valve rods, lost motion being provided
between the tappets and lugs. In this construction, no lost motion need be
provided inside the valve chest, the arm O and lever P being in constant or nearly
constant engagement with their respective lugs.
The arrangement of the cross motion with its plane of movement parallel, or
substantially parallel, with the plane of movement of the valve, reduces the
vertical measurement of the engine, permitting the cross motion to be placed
within the steam chest without materially increasing the size of the latter.
While the construction shown and described forms a simple and convenient
arrangement of parts embodying the invention, it will be understood that the
invention is not to be limited to the specific construction shown, as various other
devices for carrying it out may readily be provided by one skilled in the art.
Although the invention is described as applied only to a simple duplex engine,
it will be understood that it is equally applicable to compound engines of this type.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
from abroad, I declare that what I claim is :-
1. In a duplex engine, the combination with the steam cylinders on opposite
sides of the engine and their valves, of valve rods operating the valves on the
opposite sides of the engine from the valve rods, the movement of one of the valves
being reversed relatively to the piston of the opposite side of the engine, substantially
as described.
2. In a duplex engine, the combination with the steam cylinders on opposite

page_text: sides of the engine and their valves, of valve rods operating the valves of the
opposite side of the engine from the valve rods, and actuated from their own
side of the engine, the movement of one of the valves being reversed relatively
to the piston on the opposite side of the engine, substantially as described.
3. In a duplex engine, the combination with the steam cylinders on opposite.
sides of the engine and their pistons and valves, of valve rods operating the
valves on the opposite side of the engine from the valve rods, and actuated by
the piston rods on their own side of the engine, the movement of one of the
valves being reversed relatively to its actuating piston rod, substantially as
described.
4. In a duplex engine, the combination with the steam cylinders on opposite
sides of the engine and their. pistons and D valves, of valve rods operated by the
piston rods on their own sides of the engine, and cross motion devices between
the valve rods and valves on opposite sides of the engine, reversing the movement
of one of the valves relatively to its actuating piston rod, substantially as
described.
5. In a duplex engine, the combination with the steam cylinders on opposite
sides of the engine and their D valves, of cross motion devices inside the steam
chest operating the valves from the opposite side of the engine, and reversing
the movement of one of the valves, substantially as described.
6. In a duplex engine, the combination with the steam cylinders on opposite
sides of the engine and their valves, of cross motion devices inside the steam
chest, operating the valves from the opposite side of the engine, and reversing
the movement of one of the valves, said cross motion devices being constructed
with lost motion, substantially as described.
7. In a duplex engine, the combination with the steam cylinders on opposite
sides of the engine and their pistons and valves, of valve rods operated by the
pistons on their own sides, and cross motion devices inside the steam chest
operating the valves from the valve rods on the opposite side of the engine, and
reversing the movement of one of the valves, substantially as described.
8. In a duplex engine, the combination with the steam cylinders on opposite
sides of the engine and their pistons and valves, of valve rods operated reversely
by the pistons on their own sides of the engine, and cross motion devices inside
the steam chest operating the valves from the valve rods on the opposite side
of the engine, the relative movement of one of the valve rods and its valve being
reversed, substantially as described.
9. The combination with the steam cylinders on opposite sides of the engine and
their pistons and valves, of the valve rods K L operated by the piston rods on
their own side of the engine, and arm O and lever l'operated by the respective
valve rods, and operating the valves on the opposite side of the engine, sub-
stantially as described.
10. The combination with the steam cylinders on opposite sides of the engine
and their pistons and valves, of piston rods H I, valve rods K L, levers of the first
class connecting the piston rods and valve rods on the same side of the engine,
arm operated by one of the valve rods, and operating the valve on the opposite
side of the engine, and lever P operated by the other valve rod, and operating the
opposite valve, lost motion being provided between the piston rods and valves,
substantially as described,
11. The combination with the two valve rods of a duplex engine, of the rigid
arm O moved by one valve rod, and the pivoted lever P moved by the other valve
rod, and valves operated by said arm and lever, substantially as described.
Dated this 6th day of July 1891.
:
NEWTON & SON,
Agents for the Applicant.