IMPROVEMENTS IN STEAM ENGINES
Year: 1885

page_text: I GEORGE SIMPSON STRONG of 701 Chestnut Street in the City of Philadelphia
State of Pennsylvania United States of America Engineer do hereby declare the
nature of this invention for "IMPROVEMENTS IN STEAM ENGINES" and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
This Invention consists of certain improvements in Steam Engines relating
more particularly to the valve motion and construction of the valves and cylinder.
In the accompanying drawings,
Figure 1 is a side view of my improved valve motion or gear and cylinder.
Figure 2 is a plan view.
Figure 3 is a detached perspective view of part of the valve gear.
Figure 4 is a general diagram illustrating the action of my improved valve gear.
Figures 5 and 6 are diagrams on a larger scale illustrating the motions
produced.
Figure 7 is a view of the valve gear in its simplest form.
Figure 8 is a view of a modified form of the gear.
Figure 9 is a transverse section on the line 1-2 figure 1.
Figure 10 is a section on the line 3-4 figure 2.
Figures 11 and 12 are views illustrating the construction of the valves and
seats.
Figure 13 is a sectional elevation of one of the valve lifters.
Figure 14 is a 'section on the line 5-6 figure 13.
Figure 15 is a diagram illustrating the movement of the valve lifter and
Figure 16 is a diagram of the resulting motion of the valve.
Referring in the first instance to Figures 1. 2 and 3 W is the cylinder of a
locomotive engine and V V are the valve lifter chests, v being the rock shafts for
the lifter which are attached to the valve rods B B'.
The valves are what are termed gridiron valves as shewn in figures 9 and 10.
A is the connecting rod of the engine secured to the usual cross head guided in
ways w projecting from the cylinder W.
B is the steam valve rod and B₁ the exhaust valve rod.

page_text: To simplify the explanation of the parts I will describe simply the steam valve
operating mechanism as it is duplicated in the exhaust valve mechanism as shown
hereafter.
D is a fixed segment or piece made in the arc of a circle and secured to any
available fixed part of the engine-The dotted line a represents the central line of
the engine, that is the line passing through the centres of the cylinder and crank
shaft.
It is also the central line of the connecting rod when the crank is either at its
rear or front dead centre-In Figure 1 the crank pin is supposed to be at the rear
dead-centre.
To the segment D is fitted a block E which is adjusted thereon. One end of a
link F is secured to this block E by a pin e, the opposite end of the link being
connected by a pin f to a lever H, which has a short armi h connected by a pin d
to one end of a rod G the opposite end of the said rod G being connected by a
pin to the valve rod B, which is also connected to the upper end of a rocking
link I by a pin i, the lower end of the said link I being hinged by a pin g to any
available fixed part of the engine.
This rocking link supports the end of the valve rod B, and the link G, when the
two are connected together.
A lever J is attached to the connecting rod A by a piu m the other end of the
lever J being attached to the link K by a pin k. This link K, is pivoted to a fixed
part of the engine, on the same side of the connecting rod as the rest of the valve
gear.
The rod H is connected to the lever J by a pin in the present instance about
midway between the pins m and k.
The object of the lever J, and link K, constructed and combined as described is
to overcome the error that would ensue if the lever H, were pivoted directly to
the connecting rod A, as it is necessary to have an equal opening of the ports at
both ends of the cylinder; hence by pivoting the lever J to the connecting rod A
at m, and the rod H to the lever at 6, the pin 7 will describe the irregular oval P
(Figure 4) which extends about double the distance below the line x, that it does
above, thus compensating for the error.
I have described above only the steam valve operating mechanism, but the same
description will apply to the exhaust valve operating mechanism, The two are
identical, both in construction and operation and I have similarly lettered the
parts of the exhaust apparatus with the addition of the numeral "1," Both
mechanisms can be operated independently of each other by means of the
rods j,, which connects the blocks E, E¹ with the operating stand in the cab
of the engine.
In explaining the operation of the above described valve motion; reference may
be had to Figures 1 and 4, the line x, in the diagram Figure 4, corresponding with
the line in Figure 1.
The parts (as illustrated in Figure 1,) are shown in the position when the crank
pin a is at its rear dead-centre, that is, the pin a is at its nearest point to the
cylinder, and the piston is at the rear end of the latter, the centre line of the rods
being shewn by full line in the diagram and marked with the same reference
letters as in Figure 1.
The circle M indicates the path of the centre of the crank pin a the oval N the
path of the pin m and the irregular oval P the path of the pin The block E is
midway between the two extreme adjusting points that is to say "mid gear."
When the crank pin a has been moved in the direction of its arrow in the
diagram, until it is at the outward dead centre, that is, at number 24, the several
pins mand k, will also be at the points numbered 24, in their several paths, the
pin fwill be in the same position when the crank pin is at its front dead centre 24,
as when at its rear dead-centre, I but the pin d will have a movement from I, in
the direction of its arrow to 24, as shown in the enlarged diagram, Figure 5, being

page_text: one half of an irregular oval, the pin f moving to the point number 12, and back
again to 24, when the block E is at mid-gear (See Figure 6).
When the crank pin a; is at 24, the piston of the engine will be at its extreme
forward limit.
In returning, the crank pin a travels from the front dead-centre to the rear
dead-centre 48 or I, in the direction of its arrow, the pins m and travelling the
upper half of the path 48 or I but the pin / travels in the same path going from
the front to the rear dead-centre, as in going from the rear to the front dead-
centre.
The pin travels from the point 24 to the extreme point 36, (Figure 6) back
again to 48 or I, and the pin d travels from 24 to 48, being the remaining half of
the irregular oval, as described above, and indicated by the dark section, Figure 5.
It will now be seen that a compound movement is imparted to the lever H,
namely, first, a vibrating movement, on its fulcrum pin f and second, a movement
of the lever by which, under the control of the rod F, the fulcrum pin is caused to
traverse in the arc of a circle. To this second movement is due the throw of the
valve, the extent and direction of the throw being determined by the adjustment
of the block on the segment. To the first movement, that is to the vibration of
the lever on its fulcrum pin.is due the lap, lead, and cut off of the valve.
I have shown both in Figure 1, and in the diagram Figure 4 the block E in its
mid gear position, marked z. The movement of the crank pin when the block E
is in this position will not affect the fulcrum pin f and consequently will not open
the valve ports, but the lever H will have its vibrating movement on the fulcrum
pin, and the pin & will describe the irregular oval shown by dark section,
Figure 5, which will not affect the opening of the valves.
By moving the block E from the mid-gear position z, to the full throw position z¹,
the pin f will travel in the arc of the circle w¹, Figure 6 and the pin d will travel
in the irregular path u¹ Figure 5, the ports of the engine being full open and
having the required lap, lead, and cut off.
Should the block E be adjusted to the position the travel of the fulcrum pin
will be in the arc of the circle w² and the motion of the valve reversed, the pin d
will travel in the irregular path u² Figure 5.
Turning now to figure 8 which represents the valve motion without the lap, lead
and cut off gear, the block E, being raised on the segment D; in this instance the
arm h of the lever H is dispensed with and the rod G connected directly to the
pin f
This gear is intended to be used on engines in which the lead of the valve is
obtained by mechanism outside of the valve operating mechanism.
When the block E is at mid-gear there will be no movement whatever of the
valve rod, the pin f traversing in the arc w, but when the block has been adjusted
to its lowest point ¹ the pin will traverse in the arc w¹, and the valve will have its
full throw. Should the block be adjusted to the position 23 the pin f will traverse
in the arc w and the motion of the valve will be reversed.
Referring to Figure 7, which represents the valve motion in its simplest form,
the rod F is secured to a position on any fixed part of the engine; the valve rod B
in this instance sliding in a bearing in this fixed projection. In this case, the engine
is intended to run forward and is regulated by the ordinary throttle valve.
In most cases, it is desirable to make the valve motion as shown in Figure 1 and
as illustrated in the diagram Figure 4 so that the two movements.of the valve may
be obtained, one being the ordinary throw of the valve, the other the lap, lead, and
out-off of the valve.
It will be observed that owing to the use of the lever J, and of the pivoted
link K, on the same side of the connecting rod as the other levers in connection
with the other parts as shewn, none of the valve gear lies below the connecting
rod, a feature of importance, especially in locomotives, for in them it is desirable to
have the operating levers as far from the track as practicable to avoid the throwing

page_text: of dirt up into the working parts, and also to avoid, possible obstructions along the
track striking operating parts if such were situated below the connecting rods. In
other forms of engines the construction described takes all the valve gear away
from the bed plate, or condenser, and makes the structure more compact.
I have shown in the diagram Figure 4, my valve motion as applied to a gridiron
valve but it will be understood that the motion can likewise be applied to other
forms of valves.
On one side of the steam cylinder W is the extension or saddle Y, containing the
valve and passages the whole being preferably cast in one piece, C C are the steam
passages terminating at the inlet c, and U, U, are the exhaust passages terminating
at the discharge opening u', which is close to the inlet.
There are two ports p, one near each end of the cylinder (see Figure 11) and
for each port there are a steam valve R and an exhaust valve S, all the valves being
preferably of the gridiron style shown in Figs. 9 and 10-The exhaust valve S, is
on one side of the port, the steam valve being on the other side, the two valves
being preferably arranged relatively to each other at or about the angle shown.
The edges of the seat q. of each steam valve R, are made in arcs of circles so as
to be fitted to bearings made in corresponding arcs of circles by boring (as described
hereafter), the same rule being observed in respect to the seat t, of each exhaust
valve.
This arrangement of steam and exhaust valves with the inlet and outlet ports in
close relation to each other, and the passages C. U. forming direct communications
between the said openings and the valves and so dispensing with the steam chest
forms a compact and convenient construction which permits of the casting
containing these passages being utilized as the saddle or part of the saddle for the
boiler, and by casting this extension or saddle in one piece with the cylinder, as
shown, the whole structure is extremely strong and the building is greatly
simplified and cheapened, as no fitting or facing is needed and only the cylinder and
the seats of the valves have to be bored out.
The plan possesses the further advantages of simplicity and economy in
construction and enables me to easily clothe with appropriate lagging the entire
cylinder excepting the small portion where the cylinder meets the extension Y.
The two exhaust passages are separated from each other by a partition u²,
Fig. 10, so as to prevent a conflict between the two volumes of exhaust steam.
The less space between each steam valve and the adjoining exhaust valve, the.
better;
hence the arrangement of the valves at an angle in respect to each other, an
arrangement which permits free access of live steam to and the free passage of
exhaust steam through the port while the space between the valves is contracted.
The course of the steam and exhaust passages from the cylinder to the outlets
are so clearly shown by dotted lines in Figs. 2 and 10 as not to need explanation
but these passages may be reversed, that is to say, C. C. may be the exhaust
passages and U. U. the steam passages, in which case R will be the exhaust valve
and S. the steam valve.
The cylinder has at one end two cylindrically chambered chests d¹ and f¹ (see
Figs. 11 and 12) and at the opposite end two similar chests d¹ and f¹ these chests
extending entirely through the casting, of which the cylinder forms one part, and
its extension or saddle the other part.
The chests . . contain each a steam valve R and its seat q. whilst the
chests f f are devoted each to an exhaust valve S. and its seat t.
Each chest is truly bored and each seat q-(see Fig. 12) has edges made on the
arc of a circle to concide with the bore of the chest in which it is secured by tubes
or rods r. driven into holes bored partly in the edges of the seat and partly in the
wall of the chest, the tube or rod thus forming a key for securing the seat rigidly
in position within the chest. Tubes are preferred, because after their introduction
they can be expanded by hydraulic pressure,

page_text: Each valve is of the gridiron style and each seat has openings to correspond with
those of its valve.
The edges of each valve are made on a less curve than the bore of the chest as
shown in Fig. 12, so that the valves are at liberty to leave their seats in order to
permit the escape of water of condensation which may have collected in the cylinder
and which is subjected to pressure as the piston reaches the end of its stroke.
The plan described of applying the seats q-, t to the chest has the advantage of
economy, for the chests can be bored by an ordinary boring machine and the seats
made to fit accurately to the chest by turning the edges in an ordinary lathe.
Not only is the expensive work demanded in the construction of ordinary
valves and seats avoided, but the usual covers for the valve chests are rendered
unnecessary.
The chests are closed at the bottom by plates ¹, k¹, (Figs. 9 and 10) and at the
top by plates o o (not shewn in Fig. 10) the spindles of the valves passing through
stuffing boxes on the latter plates (see Figs. 1. 13 and 14).
In order to prevent any back lash of the steam valves except when they are
subjected to undue pressure by the accumulated water of condensation as above
described I use the device shown in Figs. 10 and 12.
A socket s fits against the back of the valve between ribs on the same and into
this socket projects the plain end portion of a set screw n, the threaded portion of
which screws into a plug p¹ which is screwed into the wall of the valve chest.
A spiral spring intervenes between the socket and a disk against which bears a
shoulder on the set screw so that by turning the latter the rigidity of the spring
may be increased or diminished.
There are two of these devices for each steam valve which can slide freely against
the sockets and which are maintained in contact with their seats by the springs.
Referring now to Figs. 1. 2. 9. 13. 14. 15, and 16 a chest V for each valve is
bolted to the main valve chest and through a stuffing box a¹ screwed into the
bottom of the chest V passes the valve spindle Q the upper end of which is secured
to a projection b¹ on the bar D¹, the latter terminating at its upper end in a
piston h¹ adapted to a small cylinder A¹ which serves as an upper guide for the
valve spindle.
A rock shaft v passes through a projection on the chest V and on this shaft is an
arm L the pin m² of which is connected by a rod H to a pin passing through
the bar D'. On this rock shaft is a forked arm N¹ carrying a pin O for receiving
the end of the rod (an eccentric rod for instance) through the medium of which tho
said arm and rock shaft are vibrated.
ย
On referring to Fig. 1. it will be seen that the centre of the rock shaft vis at a
distance from the line 1-2 drawn through the centre of the valve spindle and
cylinder.
The relation of the two arms L and N¹ to each other is indicated in Figure 13
by the dotted line passing through the centre of the pin m¹ and the centre of the
rock shaft and the line passing through the latter centre and the centre of the
pin O of the arm N¹.
Assuming that a uniform vibrating motion is imparted to the arm L of the rock
shaft to the extent indicated by the lines and x¹y and the dotted segment
Fig. 13 the upward movement of the valve spindle will be of a differential character,
which can be best explained by reference to the diagram Figure 15, in which the
line 2-2 is the centre line of the valve spindle, and X³ the centre of the rock shaft,
the dotted segment indicating the course of the centre of the pin m¹ of the arm L,
and the points 7, and 6 indicating the extent of vibration of the said pin's centre.
During the movement of the said pin from 7 to 4 that is, more than half of the
extent of its vibration, there will be the slight movement of the valve spindle
indicated by the distance between the horizontal lines 3** and 4** crossing the
line 2-2, the distance of the line 5×× from the line 3** showing the distance to
which the valve spindle will be raised when the crank pin has reached the point 5.

page_text: '
While the said pin, however, moves from the point 5 to the point 6 nearly at right
angles to the spindle, there will be a rapid rise of the valve spindle from the
horizontal line 5** to the horizontal line 6**.
The path of the valve produced by the above described motion is illustrated in
the diagram Figure 16, from which it will be seen that the valve is kept in
constant motion. During the "lap" this movement is very slight; and not enough
to affect the correct opening of the ports or to cause perceptible friction or wear on
the valve or valve gear. The movement is sufficient, however, to prevent the valve
from sticking to the seat, as is apt to be the case where the valve stops at a certain
point in its path.
This continued movement during the "lap" is caused by the passing of the
arm L, to the slight extent described, beyond a line drawn through the centres of
the pin O, and shaft v.
This differential movement for a gridiron valve is the most advantageous which
can be obtained without the aid of a cam, which is always objectionable owing to
the constant friction of one surface against the other.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First. The combination in valve gear for steam engines, of the following
elements, namely:-first the pivoted link F, having a fulcrum pin f; second a
connecting rod A, a lever J pivoted thereto and to a pivoted link K on the same
side of the connecting rod as the rest of the valve-gear, and a rod H pivoted to the
lever J. and to the link F by the fulcrum pin f; third a link G connected also
to the fulcrum pin f and to the valve rod B, all substantially as set forth.
Second. The combination in valve gear for steam engines, of the following
elements, namely: first a fixed segment D and a block E adjustable thereon;
second a lever or link H and connecting rod A, lever J and link K, pivoted on
the same side of the connecting rod as the rest of the valve gear, for imparting the
within described compound movement to the lever H; and third a link F, con-
necting the adjustable block to the lever H by a pin f, to which . lever is also
connected the valve rod, substantially as set forth.
Third. The combination in valve gear for steam engines, of the following
elements namely: first a fixed segment D and a block E, adjustable thereon;
second a lever H, having its fulcrum pin connected to the said block, and having
an arm h connected to the valve spindle, and pivoted on the same side of the
connecting rod as the rest of the valve-gear; third the connecting rod A, lover J,
and link K, for imparting the within described movement to the lever H, all
substantially as set forth.
Fourth. The combination of the cylinder having a port p-, a steam valve on one
side thereof and an exhaust valve on the other, with the steam inlet c and outlet u'
adjacent to each other and the passages C and U leading from the port to the said
inlet and outlet substantially as set fourth.
Fifth. The combination of the cylinder having ports p-, at opposite ends a
steam valve on one side and an exhaust valve on the other side of each port, with
the steam inlet c and outlet u¹ adjacent to each other and the passages C and U
the latter having a partition u², substantially as described.
'
Sixth. The combination of a steam cylinder having a port p-, with steam and
exhaust passages C and U leading from opposite sides thereof and having
valves R. S on opposite sides of said port and at an angle to each other sub-
stantially as setforth, to bring them close together.
Seventh. The combination of the cylinder with the saddle or extension Y cast in
one piece therewith, and containing inlet and exhaust ports C, U, with steam and
exhaust valves at both ends of the cylinder substantially as set forth.
24

page_text: Eight. The combination of the circular valve chest of a steam engine, with a
valve seat having edges made in arcs of circles to coincide with the bore of the
chest and key-ways partly in the edges of the seat and partly in the walls of
the chest, with rods or tubes for securing the chest in place and forming a packing
between the two as set forth.
Ninth. The combination of the valve spindle and the rock shaft with an arm L
attached to the shaft and connected to the spindle at a point substantially as set
forth, the said arm having a movement from a position at about right angles to the
spindle to a point on or beyond a line drawn through the centre of the shaft v and
parallel with the said spindle.
Tenth. The combination of the valve spindle and the rock shaft with an arm L
and a connecting link H¹, the said arm L having a movement within the limits of
the lines 6-7 past a line drawn through the centre of the shaft v, and of the
connection of the link with the spindle, substantially as set forth.
J. HENRY JOHNSON,
Applicant's Agent.