IMPROVEMENTS IN ENGINES WORKED BY STEAM OR OTHER FLUID PRESSURE
Year: 1882

page_text: LETTERS PATENT to Jabez James and Walter Wardrop, both of Princes
Street, Commercial Road, Lambeth, in the County of Surrey, for an
Invention of "IMPROVEMENTS IN ENGINES WORKED BY STEAM OR OTHER
FLUID PRESSURE."
PROVISIONAL SPECIFICATION left by the said Jabez James and Walter
Wardrop at the Oflice of the Commissioners of Patents on the 5th January
1882.
JABEZ JAMES and WALTER WARDROP both of Princes Street Commercial Road
Lambeth in the County of Surrey. "IMPROVEMENTS IN ENGINES WORKED BY
STEAM OR OTHER FLUID PRESSURE."
This Invention relates chiefly to three-cylinder engines some of the improvements
in which are also applicable to engines having one, two, or four cylinders.
The three cylinders being placed radially round the crankshaft at angles of
about 120° to one another have their pistons arranged to act on a single crank
which revolves within a central cavity into which the exhaust steam or fluid
discharges. The side covers of the cavity have bearings for the crankshaft. Each
cylinder has a cylindrical valve case having its axis parallel and in the same plane
with that of the cylinder. Each piston is inade with a deep hollow trunk near the
bottom of which the connecting rod jointed and near the top of which is a lug
for working the valve of the next cylinder in order as will hereafter be explained.
For the purpose of obtaining short direct ports with ample area, piston slide valves
are used, each consisting of two pistons of unequal diameters connected by a short
tube, the steain or working fluid being admitted between these pistons so that
there is always excess of pressure in one direction. According to one arrangement
there is an exhaust passage through the slide communicating with the central
cavity; in another arrangement this passage is dispensed with. A link is jointed
at one end to each piston valve and at its other end to a point in the connecting.
rod of one of the other cylinders, the valve thus deriving its motion from that
connecting rod, and having its cut-off determined by the position of its attachment

page_text: to the connecting rod. The cut-off may be varied by shifting the pin of the link,
in a slot formed at the end of the piston valve, and this shift may be effected while
the engine is running by means of a lever having its spindle passed through a
stuffing-box to the exterior of the engine and adjusted by hand, or by a governor.
Otherwise the link of the piston valve may be jointed to the beforementioned lug
on the piston trunk of one of the other cylinders, in which case the cut-off is fixed
at about three-fourths of the stroke. In this case we use separate expansion gear
as will be presently described.
At the inner end of each main cylinder there are narrow passages extending
round nearly the whole circumference and forming a communication between the
interior of the cylinder and the central cavity, when they are uncovered by the
piston as it approaches the extreme of its instroke. As they remain open during a
considerable part of the revolution a large volume of the exhaust is discharged
through them directly into the central cavity. The residue may be compressed
during the outstroke or may be partly discharged through the piston valve into
the central cavity.
When each piston valve is linked to the trunk of the adjacent piston we employ
expansion gear of the following kind. In the supply passage to each valve casing
we provide an annular gridiron valve and seating, which valve is caused to recip-
rocate so as alternately to open and close the gridiron apertures of the seating by
a connection to an eccentric on the main shaft. This eccentric which works the
three gridiron valves can be turned more or less round on the shaft by hand or by
a governor thus varying the point of cut-off.
When the engine requires to be reversible we do not connect the piston valves
to the connecting rods or trunks as above described but to arms on rocking-shafts
which project through stuffing boxes in the side of the central cavity and have
arms all three of which are worked by one eccentric which can be moved round
the main shaft by means of a sliding sleeve with helical feather.
If preferred, the exhaust instead of being discharged into the central cavity
may be discharged into spaces at the inner ends of the cylinders from which it
passes to a discharge pipe or pipes.
The engine may be made to act as a compound engine by employing one of the
cylinders as a high pressure cylinder and the other two which may be of larger
diameter as low pressure cylinders. In this case the cylinders need not be equally
spaced round the shaft, but the communications are arranged so that the exhaust
passes from the high pressure cylinder into the valve casings of the low pressure
cylinders. In this arrangement we prefer to derive the motion of each piston
valve from the connecting rod of one of the other cylinders as before described so
as definitely to determine the cut-off at a point to equalize the power developed in
the several cylinders.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jabez James and Walter Wardrop in the Great Seal Patent Offico
on the 4th July 1882.
JABEZ JAMES and WALTER WARDROP both of Princes Street Commercial Rond
Lambeth in the County of Surrey. "IMPROVEMENTS IN ENGINES WORKED BY
STEAM OR OTHER FLUID PRESSURE."
This Invention relates chiefly to three-cylinder engines some of the improve-
ments in which are also applicable to engines having one, two, or four cylinders.
The three cylinders being placed radially round the crank shaft at angles of
about 120° to one another have their pistons arranged to act on a single crank
which revolves within a central cavity into which the exhaust steam or fluid
discharges. The side covers of the cavity have bearings for the crank shaft.
Each cylinder has a cylindrical valve case having its axis parallel and in the same
plane with that of the cylinder. Each piston is made with a deep hollow trunk
near the bottom of which the connecting rod is jointed and near the top of which
is a lug for working the valve of the next cylinder in order as will hereafter be
explained. For the purpose of obtaining short direct ports with ample area, piston
slide valves are used each consisting of two pistons of unequal diameters connected
by a short tube, the steam or working fluid being admitted between these pistons
so that there is always excess of pressure in one direction. According to one
arrangement there is an exhaust passage through the slide communicating with the
central cavity; in another arrangement this passage is dispensed with. A link is
jointed at one end to each piston valve and at its other end to a point in the
connecting rod of one of the other cylinders, the valve thus deriving its motion
from that connecting rod, and having its cut-off determined by the position of its
attachment to the connecting rod. Otherwise the link of the piston valve may be
jointed to the before mentioned lug on the piston trunk of one of the other
cylinders, in which case the cut-off is fixed at about three fourths of the stroke.
In this case we use separate expansion gear.
At the inner end of each main cylinder there are narrow passages extending
round nearly the whole circumference and forming a communication between the
interior of the cylinder and the central cavity, when they are uncovered by the
piston as it approaches the extreme of its instroke. As they remain open during
a considerable part of a revolution a large volume of the exhaust is discharged
through them directly into the central cavity. The residue may be compressed
during the outstroke or may be partly discharged through the piston valve into the
central cavity.
If preferred, the exhaust instead of being discharged into the central cavity may
be discharged into spaces at the inner ends of the cylinders from which it passes
to a discharge pipe or pipes.
The engine may be made to act as a compound engine by employing one of
the cylinders as a high pressure cylinder and the other two which may be of
larger diameter as low pressure cylinders. In this case the cylinders need not be
equally spaced round the shaft, but the communications are arranged so that the
exhaust passes from the high pressure cylinder into the valve casings of the low
pressure cylinders. In this arrangement we prefer to derive the motion of each
piston valve from the connecting rod of one of the other cylinders as before
described so as definitely to determine the cut-off at a point to equalise the power
developed in the several cylinders.

page_text: DESCRIPTION OF THE DRAWINGS.
Figs 1 and 2 are vertical sections on planes at right angles to each other of a
three cylinder engine according to our Invention. A AA³ are the three cylinders
fitted respectively with their trunk pistons or plungers B1 B2 B3 which are linked
by their connecting rods C1 C2 C3 to one crank D on the engine shaft E, the crank
and connecting rods being accommodated within a closed central cavity, having at
each side bearings for the shaft E. Each of the pistons B B B has at the top of
its trunk a pair of pins which are linked by a forked connecting rod F¹ F F³ to a
pin in the slide of the next cylinder in order, thus the piston B₁ of the cylinder A'
is linked by the connecting rod F¹ to a pin on the slide G2 of the cylinder A, the
piston B2 of cylinder A is linked by F to slide G³ and the piston B³ of cylinder A³
is linked by F3 to slide G. Each of the slides G G G is tubular and provided
with suitable packing as shewn in the section of G. The annular steam space in
its middle is supplied by the pipe H' and the area of one of its piston parts being
slightly in excess there is a little pressure always in one direction. A portion of
the exhaust passes through the interior of the slide to the central cavity. A large
portion of the exhaust however escapes into the central cavity by apertures K
formed in the side of the cylinder in such a position that they are uncovered by
the piston at the extreme of its instroke, these apertures communicating with the
central cavity by lateral passages L as shown in the sectional plan Fig 3, taken on
the line ZZ of Fig 1. Instead of linking the slides G1 G2 G³ to the pistons B³ B B¹
respectively they may be linked as shewn in Fig by the connecting rods F³ F² F'
to pins on the connecting rods C³ C²C respectively.
Having thus described the nature of our Invention and in what manner the
same is to be performed we hereby declare that we make no general claim to the
construction of multiple cylinder engines having their pistons linked to a single
central crank, but we claim in respect of such triple cylinder engines.
Working from the piston or connecting rod of each cylinder the slide of the
next cylinder in order, substantially as herein described.
In witness whereof I the said Jabez James have hereunto set my hand
and seal this Third day of July in the year of our Lord One thousand eight
hundred and eighty two.
JABEZ JAMES. (L.S.)