Improvements in Valves and Valve Gear for Steam and similar Engines.
Year: 1887

page_text: Date of Application, 12th Apr., 1887.
Specification Accepted, 13th May, 1887.
Improvements in Valves and Valve Gear for Steam and similar
Engines.
I, WILLIAM WRIGHT, a citizen of the United States, residing at Newberg in the
County of Orange, and State of New York, one of the United States of America,
gentleman, do hereby declare the nature of the said 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 has relation to an automatic cut-off valve and gear for controlling
the supply of steam to the cylinder of an engine in such a manner that the engine will
run at a uniform speed of rotation without regard to the amount of work it is required
to perform, so that when the load is suddenly increased or diminished the supply of
steam is increased or diminished automatically, and as a consequence of the increase
or diminishing of the load. Another object in view is to provide cut off valves of
such construction as to increase their serviceability by lessening the tendency to wear
in their seats, especially at or near the ports communicating therewith.
Another purpose of the invention is to devise means which shall operate the valves
controlling the supply of steam without disengaging their connections with the wrist
plate and to reduce the broken connections necessarily involved to a single point in
the mechanism employed.
Another feature of my invention is that the valves and valve controlling mechanism
are all located, below the cylinder the latter being provided with a single port at each
end, which by subordinate passages, communicates with either valve and with the live
steam passage or exhaust chamber in accordance with the position of the valve. By
the construction and arrangement of parts just mentioned usual waste room in the
cylinder is reduced to a minimum and the arrangement of the parts as a whole is
exceedingly compact. Other objects and advantages of my invention will appear in
the following description, and the novel features will be particularly pointed out
in the claims.
Referring to the drawings.
Figure, 1, is a side elevation of a cylinder and bed provided with my improved
cut off mechanism

page_text: Fig. 2, is a side elevation of the rocker arm, wrist plates and dash pot, with a
portion of the bed in section.
Fig. 3, is a plan of a portion of the bed, the dash-pots and live steam valve stems
a rock shaft connected with a governor, and a horizontal section through the rocker
arm, and wrist plates.
Fig. 4, is a longitudinal section of the live steam valve its stem and arm, together
with a transverse section of the lower part of the steam cylinder.
Figs. 5, and, 6, are cross sections of the steam valves, open and closed
respectively.
Fig. 7, is a transverse section of the lower part of the cylinder, a longitudinal
section of the exhaust valve, its stem and arm being in side elevation, and the relative
location of the rocker shaft and the bed, the latter in end elevation and partly
in section.
Fig. 8, is a cross section of the exhaust valve with the port open.
5
Fig. 9, is a group showing edge and side views and a plan of the left sectional 1
wrist plate.
Fig. 10, is a group showing similar views of the other sectional wrist plate.
Fig. 11, is a group showing front and side views and a plan of the trip
catches and,
Fig. 12, is a perspective of a portion of the valve block.
Like letters of reference indicate like parts in all the figures of the drawings.
2
A, represents the bed of the engine, and it has cast there on bearings, B, B, at
opposite sides thereof, and supports the cylinder, C, which in this instance has the
head I cast thereon and is provided with the opposite head, K, secured in any desired
manner. G, is the piston, and, H, the usual eccentric rod. There is a single port, P, 2
at each end of the cylinder, a live steam passage, S, and an exhaust chamber, E, with
communicating passages, hereinafter described.
N, N, are the exhaust valves and, 0, 0, are the supply valves, and these are arranged
so that one of each communicates at each end of the cylinder with the port, P, thercat,
and the supply valve, O, and exhaust valve, N, are arranged as close to each other as
practicable without weakening the construction of the cylinder. The valves are all
cylindrical and fitted in bored seats arranged transversely of the cylinder, whereby
the fitting of the parts is accomplished with a minimum of hand labor and with the
accuracy of machine work.
Referring more particularly to figs. 4, 7, and, 11, a detail description of the con-
struction of the valves will be readily understood and a description of one will answer
for all, as they are alike, except that the stems of the supply valves project from one
side, the front, (see fig. 1.) of the engine, while the stems of the exhaust valves project
from the rear side. (See fig. 7) The seats having been bored below the ports, P,
there remains solid metal at all points, except directly at the port and its communi-
cating passages. A cap or head, V4, fig. 4, closes one end of the valve seat or bore,
and the stem, v, together with a valve shell, o³, which is a true cylinder, serves, by
the cheaper and more accurate fitting by the lathe, to fill the bore, and has such
an extended bearing beyond the port that all wear by contact with the edges of
the port is avoided.
of
Within the cylindrical valve shell is fitted a substantially oblong block, O, having
a port, o, which registers with a similar port in the shell. The upper portion, o²,
the valve block is convex, and so set into the shell as to constitute a portion of its
periphery, whereby the shell and block jointly constitute, exteriorily the cylindrical
valve which fits the cylindrical bore or valve seat formed across the cylinder. The
block, like the shell, extends beyond the longitudinal dimensions of the port, P, and
therefore it, like the shell is not worn by contact with the edges of the port, and what-
ever wear that does occur on the convex face of the block is compensated for by one
or more springs placed in grooves, o, formed in the bottom of the block, which con-
stantly act to force the block, which constantly act to force the block against the walls
of the valve seat. A hood, V³, is secured in any suitable manner to the cylinder,

page_text: over the end of the valve seat, and is provided with a bearing for the valve stem so
that it and the valve may be rocked or oscillated by its arm, V.
When the valve is open its port, o, communicates with the port, P, by means of the
passage, a, and directly with the live-steam passage, S. These ports and passages are
so relatively arranged that communication may be entirely cut off, as shown in fig. 6,
when each of the exhaust valves communicates, with the port, P, by means of the
port, n, the passage, a, and a passage, b, leading to the exhaust chamber, E. Suitable
glands V, are provided in each of the hoods for making a steam tight joint on each of
the valve stems. I will now proceed to describe the mechanism which I have devised
for operating the supply and exhaust valves, and this with a view of controlling the
operation of the engine, to the end that its speed may be uniform notwithstanding
any ordinary change in its load: or, in other words, to maintain a constant control of
the supply and exhaust of steam in accordance with the requirements of the work to
be performed, which may, and ordinarily does, constantly vary.
Let, G¹, fig. 3, represent any rod which is so connected with a governor as to be
raised and lowered, as usual, by the action of the governor. This motion of the
rod, G', is communicated to a tappet or cam projection, p, by means of a rock
shaft, W, on which the tappet and a rock arm, G2, are mounted. These parts are
arranged contiguous to and operate upon the valve controlling devices. Z, figs. 1, 2,
and, 7, represents a rock shaft mounted beneath and at a right angle to the cylinder, C,
in the bearings, B, and said shaft is provided at the rear side of the cylinder with a
rigidly secured wrist plate or rock arm, D³, fig. 7, the wrist pins, u³, u, of which are
connected to the wrist pins, U1, U2, of arms mounted upon the exhaust valve stems
by adjustable connecting rods, u¹, u² (see dotted lines, fig. 1.) similar to the connecting
rods, m¹, m². (Shown in full lines in said figure.) On the front side of the cylinder
the arms, V, of the supply valves, O, are connected by rods, m, m², to segmental or
sectional wrist plates, 112, (details of which are shown in figs. 9, and, 10,) which are
loosely mounted upon the shaft, Z, and by means of weights or their equivalents, the
dush pots, X, Y (connected by rods, a, y, to the wrist pins, n', n², of said sectional
wrist plates) are quickly thrown in one direction to close the supply port when
demanded by the action of certain other devices, (to be described) which determine
when sufficient steam has entered the cylinder to keep the engine at the desired
uniform speed regardless of any change in its work. Each of the sectional wrist
plates is provided with a steel latch keeper, g', g², respectively, and their hubs
are offset, so as to bring the plates into a common plane when mounted on the
shaft, Z.
Behind the wrist plates there is mounted rigidly upon the shaft, Z, a rocker arm, D,
the hub, D', of which abuts against the bearing, B. The arm D, is provided with a
wrist pin for the connection therewith of the eccentric rod, H, which is understood to
extend from an eccentric on the main shaft of the engine. It is also provided with a
removable starting bar, h. Upon the face of the rocker arm are two latches, c¹, c²,
rigidly secured to shafts, e¹, e², passing through the arm and having at their rear ends
depending arms,, f, which are arranged over and astride of the cam projection or
arm, p, of the rock shaft, W, which as before described, is connected with the governor.
The contour of the arms, 1, 2, should be such as to permit of the oscillations of the
rocker arm, D, within certain limits without lifting the latches, c¹, c², from the
sectional wrist plates, g¹, g², as this function of the arms is brought into operation by
the cam, p, through the operation of the governor.
The rod, W, is supported by a bracket, W₁, which is adjustably mounted upon the
bearing, B, the bracket being slotted at W2, fig. 2, and mounted upon the plate,
having opposite lugs, W³, and a rib, W4, fitted in transverse grooves formed in the
upper surface of the bearing, whereby the position of the cam projection, p, with
relation to the arms, 1, 2, of the latches, c¹, c², may be adjusted in order to give
accuracy and sensitiveness to the operation of these devices in tripping the latches, as
hereinafter described.
A coiled or other spring, c³, fig. 11, may be arranged above the latches with its
opposite ends resting upon the latches outside of their pivots, so that instead of

page_text: depending upon gravity alone to cause the latches to fall such motion thereof will be
rendered more positive. The operation of the mechanism above described is as
follows: The rocker arm D, is oscillated by the eccentric rod, H, and moves in like
manner the shaft, Z, upon which it is.rigidly mounted, which shaft by means of the
arms, D³, thereon and the connections, u₁, u², operates the exhaust valves, N, N, by
the arms, U1, U2, while the supply valves, O, O, are operated by the arms, V, secured
thereto and connected by the adjustable rods, m¹, m², of the sectional wrist plates, 1, 12,
when either one of the same is connected to the rocker arm by means of one of the
latches, c', c², pivoted thereon. The action of these connecting rods (by reason of
their relative proportions and positions to the position of the axial line of the shaft, Z,
and of the point of the pivotal connection of the rods of the sectional wrist p plates)
is in the nature of a toggle lever, in that as the wrist plate and the connecting rod
approach a straight line extending from the centre of the shaft, Z, to the centre of the
arm, V, of the valve the speed of movement decreases, so that the supply is quickly
cut off while the exhaust port is slowly closed. So also, when either of the latches are
tripped as hereinafter described, there is a quick action in the cut-off. As the wrist
plate pivot, n', n², fig. 1, is suddenly forced down by the dash pot, Y, or its equivalent,
a weight, the point of pivotal connection of the connecting rod, m³, with the sectional
wrist plate quickly moves from the point, a, to the point, a¹, thereby utilizing the
rapid movement of the toggle connection in suddenly closing the supply when the
latch, c², is raised from the catch, 92 of the wrist plate, 12.
Suppose for example, that the engine is running at a uniform speed with a uniform
load, and that the latch, c², is in contact with the catch, 92, and suppose that a sudden
decrease in the load occurs. Now, the governor immediately responds to the increased
speed of the engine, which is a natural consequence of the decrease of the load,
and the said governor causes the rock shaft, W, to rise, bringing the cam
projection, p, thereof into contact with the arm, f2, of the latch, c², so that in the
oscillation of the rocker arm said latch is thrown out of connection with the catch, g²,
of the sectional wrist plate, 12, which by the action of the dash pot, is suddenly brought
down to cut off the supply. The latches and their arms being duplicated, this action
of cutting off the supply will occur, when required, during the oscillation of the rocker
arm in either direction, so that either supply valve is always under control of the
governor.
It is apparent that I may locate the shaft, Z, at any other place than below and
at the centre of the cylinder, and yet employ other novel features of my invention
therewith-such as, for example, my continuously valve connected sectional wrist
plates together with means for connecting and disconnecting the same from a
inoving element operated by an eccentric, whereby the valves and their con-
trolling devices are detachably connected at but one point, and that a central one
common to all.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is :-
:-
The herein before described cylinder, its valves, and the valve gear connected
therewith.