IM- PROVEMENTS IN STEAM ENGINES
Year: 1873

page_text: LETTERS PATENT to Hunter Henry Murdoch, of No. 7, Staple Inn, in
the County of Middlesex, Patent Agent, for the Invention of "IM-
PROVEMENTS IN STEAM ENGINES." -A communication from abroad by
Bede and Company, of Verviers, in the Kingdom of Belgium, and
Farcot and Sons of Saint Quen, near Paris. France Enginee
Sealed the 14th October 1873, and dated the 22nd May 1873.
PROVISIONAL SPECIFICATION left by the said Hunter Henry Murdoch
at the Office of the Commissioners of Patents, with his Petition,
on the 22nd May 1873.
I, HUNTER HENRY MURDOCH, of No. 7, Staple Inn, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM ENGINES," to be as follows:-
This Invention, as communicated to me, relates to that class of steam
engines generally known as "Corliss engines," and it consists in the
improvements herein-after described in effecting the distribution of the
steam in such engines.

page_text: According to these improvements the governor spindle of the engine
is by means of a shaft and suitable bevilled gearing caused to rotate at
the same speed as the main shaft from which it receives motion. Upon
the said governor spindle are affixed two cams, one above the other.
One of the said cams gives motion to the steam valves, whilst the other
of the said cams operates the exhaust valves. The action of each of the
said cams is communicated to the parts actuated thereby by means of a
cam box or frame suitably guided. The exhaust cam box is connected
at either end directly to one of the exhaust valve rods by a connecting
rod and crank. Upon each end of the steam cam box is mounted on a
horizontal pivot a bell-crank lever, consisting of a slightly curved
vertical arm, and a horizontal arm or hook having upon its length a
projecting catch capable of engaging with and pushing forward the
rectangular head of a piston rod affixed to a piston working in an air
cylinder, the other end of which piston rod is connected by a connecting
rod and crank to the steam valve rod, and gives motion thereto to open
the steam valve. The vertical or upright arm of each of the said bell-
crank levers or hooks passes through a beam suspended by rods to the
acting collar of the governor, so as to slide up and down on the governor
spindle or on a socket in which passes the said splindle, and on which
the said beam can slightly oscillate. At each end of the beam is
mounted on a pin a roller against which the vertical curved arm of the
corresponding hook abuts, and is forced to stop in its forward motion,
which causes the catch of the horizontal arm to disengage from the
piston rod, and allows the piston to fly back under the action of a
suitable spring, and to close the steam valve.
As the vertical arms of the hooks are slightly curved outwards it will
be readily understood that when the speed of the engine increases the
governor will cause the oscillating frame to rise, and the said lever arms
will come sooner into contact with the rollers, and will act to shut off
the steam at an earlier period, and the contrary will take place when
the speed of the engine diminishes.
Either flat or spiral springs may be used for driving home the piston
rods, and closing the steam valves. Each of the said springs is attached
to one of the piston rods, and also to the cam box, either directly or
indirectly, so that the spring which is to close one of the steam valves is
bent or compressed (according to the nature of the spring used) during
the time the other steam valve is in action, cach spring being alternately

page_text: bent or compressed to its greatest extent from the time the steam valve
to which it is connected begins to open till the moment it begins to
close. By connecting each spring to one of the pistons or piston rods,
and also to the cam box when the hook of the bell-crank lever is
engaged with the piston rod head, and the cam box advances in the
direction of the said spring, the spring remains bent or compressed,
because the piston or rod upon which it is pressing moves onward with
the parts connecting it with the cam box, and it is only when the piston
rod is disengaged from its hook that the spring attached to the cam box
acts upon the piston or rod. Or steam may be substituted for the said
springs by causing the said steam to enter the small air cylinder at the
side opposite to that where the air escapes by means of small pipes
receiving steam either from the steam jacket of the engine or from the
steam pipe. When steam is used as a substitute for the springs the air
cylinder, which then becomes a steam cylinder, may be provided with
two valves pressed upon by suitable springs, one of the said valves
allowing the superfluous steam to pass from one side of the piston to the
other, and the other valve allowing a part of the steam when the piston
is being forced home to return to the steam jacket or steam pipe of the
engine. By this means the strain upon the cam when forcing back the
piston against the steam is diminished, and part of the power lost in the
compression of the steam may be utilized.
By the arrangement of parts herein-before described the governor has
to exert scarcely any power in disengaging the steam valve from the
action of the cam; and as the governor spindle gives motion to the
steam valves, should any accident cause the governor to stop the distri-
bution of steam to the engine, would also be arrested, and the engine
instead of flying off at a dangerous speed without control would cease to
act. And as the two cams actuating the steam and exhaust valves are
independent one of the other their position on the governor spindle may
be adjusted so that steam may be admitted to the cylinder up to eight-
tenths of the stroke.
According to this Invention the steam cylinder is constructed in four
pieces suitably secured together, namely, the cylinder, the steam jacket,
and the top and bottom covers. The steam chests are formed in the two
covers. The steam valves are made to rest against the vertical sides of
the covers, and the exhaust valves are fitted to the bottom of the covers,
and form a moveable part of the same, forming in section when closed a

page_text: continuous flat and round surface with the said covers, thus reducing the
clearance or unprofitable steam space at each end of the cylinder to the
smallest possible space. The steam jacket is constantly supplied with
steam from the boiler before the said steam enters the cylinder, and as
the steam chests form part of the said steam jacket the steam comes
from the boiler directly on to the steam valves.
In order to stop the engine immediately suitable mechanism actuated
by hand is made to disengage both hooks simultaneously.
continuous flat and round surface with the said covers, thus reducing the
clearance or unprofitable steam space at each end of the cylinder to the
smallest possible space. The steam jacket is constantly supplied with
steam from the boiler before the said steam enters the cylinder, and as
the steam chests form part of the said steam jacket the steam comes
from the boiler directly on to the steam valves.
In order to stop the engine immediately suitable mechanism actuated
by hand is made to disengage both hooks simultaneously.
To start large engines constructed according to this Invention small
cocks may be used at each end of the cylinder, so as to let the steam.
from the steam jacket directly into the cylinder.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Hunter Henry Murdoch in the Great Seal Patent
Office on the 21st November 1878.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HUNTER
HENRY MURDOCH, of No. 7, Staple Inn, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of May, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Hunter Henry Murdoch, Her special license that
I, the said Hunter Henry Murdoch, my executors, administrators, and
assigns, or such others as I, the said Hunter Henry Murdoch, my
executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for " IMPROVEMENTS
IN STEAM ENGINES," a communication to me from abroad by Bede and
Company, of Verviers, in the Kingdom of Belgium, and Farcot
& Sons, of Saint Ouen, near Paris, France Engineers, upon the
condition (amongst others) that I, the said Hunter Henry Murdoch, my

page_text: executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Hunter Henry Murdoch, 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 thereof, that is to say :-
This Invention, as communicated to me, relates to that class of steam
engines generally known as "Corliss engines," and it consists in the
improvements herein-after described in effecting the distribution of the
steam in such engines.
'
According to these improvements the governor spindle of the engine
is, by means of a shaft and suitable bevilled gearing, caused to rotate.
at the same speed as the main shaft from which it receives motion..
Upon the said governor spindle are affixed two cams, one above the
other. One of the said cams gives motion to the steam valves, whilst.
the other of the said cams operates the exhaust valves. The action
of each of the said cams is communicated to the parts actuated thereby
by means of a cam box or frame suitably guided. The exhaust cam
box is connected at either end directly to one of the exhaust valve
rods by a connecting rod and crank. Upon each end of the steam
cam box is mounted on a horizontal pivot a bell-crank lever, con-
sisting of a slightly curved vertical arm and a horizontal arm or hook
having upon its length a projecting catch capable of engaging with
and pushing forward the rectangular head of a piston rod affixed to
a piston working in an air cylinder, the other end of which piston rod
is connected by a connecting rod and crank to the steam valve rod;
and gives motion thereto to open the steam valve. The vertical or
upright arm of each of the said bell-crank levers or hooks passes
through a beam suspended by rods to the acting collar of the governor
so as to slide up and down on the governor spindle or a socket in
which passes the said spindle, and on which the said beam can slightly
oscillate. At each end of the beam is mounted on a pin or roller
against which the vertical curved arm of the corresponding hook abuts,
and is forced to stop in its forward motion, which causes the catch

page_text: of the horizontal arm to disengage from the piston rod, and allows the
piston to fly back under the action of a suitable spring, and to close
the steam valve.
As the vertical arms of the hooks are slightly curved outwards it will
be readily understood that when the speed of the engine increases the
governor will cause the oscillating frame to rise, and the said lever
arms will come sooner into contact with the rollers, and will act to
shut off the steam at an earlier period, and the contrary will take place
when the speed of the engine diminishes.
Either flat or spiral springs may be used for driving home the piston
rods and closing the steam valves. Each of the said springs is attached
to one of the piston rods and also to the cam box, either directly or
indirectly, so that the spring, which is to close one of the steam valves,
is bent or compressed (according to the nature of the spring used)
during the time the other steam valve is in action, each spring being
alternately bent or compressed to its greatest extent from the time
the steam valve to which it is connected begins to open till the
moment it begins to close. By connecting cach spring to one of the
pistons or piston rods, and also to the cam box when the hook of
the bell-crank lever is engaged with the piston rod head, and the
cam box advances in the direction of the said spring, the spring
remains bent or compressed because the piston or rod upon which
it is pressing moves onwards with the parts connecting it with the
cam box, and it is only when the piston rod is disengaged from its
hook that the spring attached to the cam box acts upon the piston
or rod. Or steam may be substituted for the said springs by causing
the said steam to enter the small air cylinder at the side opposite
to that where the air escapes, by means of small pipes receiving steam
either from the steam jacket of the engine or from the steam pipe.
When steam is used as a substitute for the springs the air cylinder,
which then becomes a steam cylinder, may be provided with two valves
pressed upon by suitable springs, one of the said valves allowing the
superfluous steam to pass from one side of the piston to the other, and
the other valve allowing a part of the steam, when the piston is being
forced home, to return to the steam jacket or steam pipe of the engine. a
By this means the strain upon the cam, when forcing back tho piston
against the steam, is diminished, and part of the power lost in the
compression of the steam may be utilized.

page_text: A is the steam cylinder; B, B, are the steam valve rods; and
B³, B¹, are the exhaust valve rods. Upon the ends of the said valve
rods B, B, B¹, B¹, are affixed cranks m, m, m³, m³, respectively. A¹ is
the governor spindle, which spindle is by means of a shaft A' and bevil
wheels a, a, caused to make the same number of revolutions as the
main shaft of the engine. Upon the said governor spindle A¹ are
affixed two cams C, C³, the cam C actuating the admission valves, and
the cam C¹ the exhaust valves. The said cam C works in a cam box or
sliding frame C suitably guided on its side, and communicates recipro-
cating motion to the said frame C³. Upon each end of the sliding
frame C³ is mounted on a horizontal pivot or axis a bell-crank lever or
click P, P¹, the said clicks being capable of turning on their axes and
moving backward and forward with the sliding frame C³, to which they
are attached. The said clicks P, P¹, are each provided with a curved
vertical arm or trip tail, which trip tails work within a socket frame b
mounted on and capable of moving up and down, the governor spindle A¹
being suspended from the acting collar of the governor by rods, as shown
in the Drawing. At each end of the said socket frame b is mounted on
a pin or axis a roller g, g¹, with which roller the trip tails of the
clicks P, P¹, come in contact alternately, as herein-after explained. The
clicks P, P¹, are fitted with two catch pieces t, t, which engage with
and act upon the heads of the rods T, T¹, of the dash pots D, D', which
rods are connected to the crank pins of the cranks m, m, on the ends of
the admission valve rods B, B. r, ³, Figure 2, are springs affixed
respectively to the rods T, T¹, of the dash-pots; the said springs are
connected together by links or rods d, d³, so that when the rods T, T',
are pushed backward the said springs will be bent and tend to draw back
the said rods, as is the case with a bow and arrow.
The exhaust valves are actuated by the cam O¹ upon the governor
spindle A¹, which cam C¹ works in a cam box C³, to each end of which
cam box is jointed one end of a connecting rod F, the other end of
which is connected to the cranks m¹ of the exhaust valve rods B¹, B¹.
The working of the valve gear is as follows:-The admission of steam
to the cylinder A is effected by the rotation of the cam C upon the
regulator spindle A', which spindle is caused to rotate with the same
velocity as the driving shaft of the engine, from which it receives motion
through the shaft A* and bevilled gearing a, a¹. The rotation of the
said cam O causes the sliding frame C³ with its clicks P, P¹, to move

page_text: alternately to the right and left, and when the said clicks advance in
either direction the catch pieces t, t¹, alternately engage with the heads
of the corresponding dash-pot rods T, T, and push back the said rods,
which acting on the cranks m, m, open the steam valves. As the
clicks P, P¹, move to the right or left their trip tails working in the
socket frame b alternately approach and recede from the rollers g, g¹,
and coming in contact with the said rollers their motion is arrested; the
clicks P, P¹, are then caused by the continued advance of the frame C*
to turn upon their axes and disengage the catch pieces t, t¹, from the
rods T, T', which rods then being actuated by the springs r, r, fly back
and close the steam valves, the dash-pots preventing the action of the
springs being attended with shocks.
In Figure 1 the click P¹ is represented in the position it assumes when
moving forward to open the admission valve.
It will be seen that the catch piece is engaged with the head of the
rod T, which rod will be pushed forward till the trip tail of the said
click P² advancing in the frame 6 comes in contact with the roller g',
the click P¹ will then be caused to turn upon its centre, the catch
piece will thereby be disengaged from the rod T¹, and the rod T¹ being
actuated by the springs r, r, will fly back and close the admission valve.
In like manner the cam C will in its rotation operate the click t and
rod T to open the other admission valve, the closing of the said valve
being effected by the springs r, r², as herein-before described in reference
to the other admission valve.
It will be seen that owing to the curved form of the trip tails of the
clicks P, P', the higher the frame 6 is raised the sooner will the said
trip tails come in contact with the rollers 9, 9', respectively, and the
earlier in the stroke will the catch pieces t, t, be freed from the dash-
pot rods T, T, and the valves be closed, the closing of the said valves
being effected by the action of the springs r, r¹, the moment the clicks
P, P¹, are lifted. And as the socket or frame b is suspended to the
regulator it rises or falls according as the velocity of the engine is greater
or smaller, and consequently cuts off the admission of steam sooner or
later, according to the velocity of the engine.
The exhaust of the steam is effected by the cam O', which cam
working in the cam box C³ causes the said cam box to advance alter-

page_text: nately to the right and left, thereby actuating the connecting rods F, F,
and cranks m³, m³, to open and close the exhaust valves as required.
It will be seen that the gearing of the exhaust valves is quite inde-
pendent of that of the admission valves. The cams C, C¹, may therefore
be adjusted on the governor spindle A', so as to allow of steam being
admitted into the cylinder up to eight-tenths of the stroke of the
piston.
Figure 3 is a longitudinal elevation, partly in section, of a steam
cylinder fitted with valve gear constructed and arranged according to
this Invention, shewing an improved construction of the said cylinder,
and certain modifications in the valve gear.
Figure 4 is a sectional horizontal view of the admission valve gear
shown in Figure 3; and Figure 5 is a cross section of Figure 3 through
the cylinder cover.
The same letters of reference indicate like parts in Figures 3, 4,
and 5.
The cylinder is composed of four pieces, viz., the body A, the steam
jacket M, and the two heads or covers M', in which are formed the
steam and exhaust ports I¹ and E', and which covers contain the
admission and exhaust valves I and E. The joints are made with their
india-rubber rings inserted in shallow grooves, as shown in the Drawing.
The valves I, E, arc of peculiar shape, as represented, and being fitted
in the cylinder covers reduce the waste in port space to a minimum.
The cylinder covers M' with the steam jacket M. form a sort of reservoir
for the steam, and when the steam valves I are opened the steam enters
the cylinder directly upon the piston. The exhaust valves E form a
portion of the cylinder, and fit into the spaces E' formed in the covers
M¹ to receive them at the ends of the cylinder. The said exhaust
valves E are caused to rotato partially in either direction, thereby alter-
nately uncovering and closing suddenly the exhaust ports E¹.
The valve gear for distributing the steam in Figures 3 and 4 is similar
to that herein-before described and illustrated in Figures 1 and 2, except
that for the socket frame b, Figure 1, is substituted a beam or frame b,
Figure 3, suspended to the sleeve of the govenor by rods, upon which
it is capable of oscillating slightly; and instead of the springs ”, “ª¹³,
(Figure 2) for closing the admission valves in Figures 3 and 4, spiral

page_text: springs, ¹, are used, each of the said springs being enclosed in a
tubular casing K, K¹, upon each of the dash-pot rods T, T¹. The said
tubular pieces K, K', are attached by rods h, h, h'; h', respectively, to
the ends of the cam frame, so that when the said cam frame moves in
the direction of the tubular piece K to open the corresponding steam
valve, it draws with it the tubular picce K', and compresses the spiral
spring against its dash-pot piston. When afterward the said cam
frame moves in the direction of the tubular piece K', with the catch
piece tengaged with the rod T', the pieces h', K¹, T¹, r¹, will all move
on together till the click disengages the said catch piece t¹ from the
rod T¹. The said rod T¹ being then no longer supported will be caused
to spring back by the action of the spring r¹, the said spring ¹ being
still supported by the tubular piece K' and rods h², h¹. The other parts
of the valve gear in Figures 3 and 4 are similar to those represented in
Figure 1, and being marked with the same letters of reference a
further description would be unnecessary.
Figure 6. is a longitudinal section of a steam cylinder constructed
according to a modification of this Invention; Figure 7 is a cross section
of the same through the cylinder cover.
A is the cylinder; M, the steam jacket; M' is the top cover of the
cylinder; and M³, the bottom cover. In this arrangement the admission
valves I, I, are placed in the steam jacket, as shown, the steam ports
I, I, being formed in the side of the cylinder. The exhaust valves E, E,
are mounted in the covers, as in Figure 3. It will be seen that by this
mode of construction as the admission valves are not placed in the
cylinder covers the piston is more easy of access.
If preferred instead of a steam jacket enclosing the cylinder A a
simple channel or passage for the steam may be formed connecting the
two steam valve chests, the steam pipe being in that case connected to
the said channel or passage.
Figures 8, 9, and 10 represent in plan (partly in section) modifications
of the spring arrangements, herein-before described with reference to
Figures 1, 2, 3, and 4 of the accompanying Drawings, for closing the
admission valves of the engine upon the release of the dash-pot rods;
the object of the said modification being to cause the springs to be bent
or compressed by the cam frame.

page_text: In Figures 8, 9, and 10 the governor spindle is marked A¹; the
admission cam O; the cam frame or box C²; the clicks P, P¹; and the
dash-pot rods T, T¹.
In Figure 8 flat springs r, 1, 71, 71, are used, the said springs being
affixed by their outer ends to the frame 0%, the edges of which frame
are curved so as to cause the said springs to be bent to the proper curve;
the inner ends of the said springs engage with projecting catches upon
the dash-pot rods, so that when the said dash-pot rods are pushed back
they bend the said springs, and on the release of the dash-pot rods the
said springs cause the said rods to fly back and close the admission
valves.
In Figure 9 spiral springs r, r, r¹, r¹, are used, each spring being con-
nected at one end to a lug on the middle of the cam frame C³, and by its
other end affixed to one end of a cross bar on either of the dash-pot
rods T, T¹.
In Figure 10 the springs r, r³, are formed of concave plates of steel,
placed one above the other in pairs round a projecting tubular part of
each dash-pot, the said springs bearing on one side against a plate or
head on the dash-pot rod, and on the other side against a cross plate
attached by bars h, h, h¹, h¹, to the cam frame C³, as in Figures 3 and 4.
Figures 11, 12, 13, 14, 15, and 16 represent different modes of applying
the action of steam as a substitute for the metallic springs r, r¹, herein-
before described in reference to Figures 1, 2, 3, 4, 8, 9, and 10 of the
accompanying Drawings.
In Figure 11 T represents the dash-pot rod; and P one of the clicks
with its catch piece t. Steam is admitted continuously into the side 3
of the dash-pot through the pipe 9; and in order to diminish the force
of the steam spring thus produced a valve u, suitably pressed down by
an adjustable spring, allows a portion of the said steam to pass to the
side of the dash-pot, thereby causing there to be a pressure of, say, a
four atmospheres on the side y, and two atmospheres on the side x.
When the click P disengages the catch piece t from the head of the
dash-pot rod T the excess of pressure on the side y drives home the dash-
pot piston, and the steam at x is compressed and deadens the shock, and
is then discharged by the valve v into a steam jacket or steam passage.
In Figure 12 the excess of pressure on the side y of the dash-pot
piston p is obtained by diminishing on that side of the piston the

page_text: diameter of the dash-pot rod T; a small valve v, which may be regulated
at pleasure, admits to the side x sufficient steam to deaden the shock.
Figure 14 is a longitudinal section, and Figure 13 a cross section of
another arrangement for effecting the return of the dash-pot rods. In
this arrangement the dash-pot cover is provided with a double valve w,
the end u of which valve when raised admits steam to the part y through
the passage z, whilst the other end of the said valve w allows the steam
to escape into the atmosphere, or into a small pipe which may be used to
conduct it to a heating or other apparatus.
In order to change the position of the said double valve w when
required, the said valve is connected to a lever 7 which bears against a
projection on the end of the click P. As long as the said click P
advances, pushing before it the dash-pot rod T, the valves to remain open,
and there is no pressure of steam on the dash-pot piston p, but as soon
as the click P rises to disengage its catch piece t from the rod T, it
causes the lever to raise the double valve w closing the valve v, and
opening the valve u. The steam then enters the dash-pot aty, and
drives home the piston p and dash-pot rod T.
Figure 15 shows in elevation, and Figure 16 in cross section, a modifi-
cation of the arrangement represented in Figures 13 and 14. In this
arrangement less steam is required than in the arrangement herein-
before described in reference to Figures 13 and 14. In Figures 15
and 16 the dash-pot communicates on the side x of the piston p by a
passage with a valve chest provided with a slide valve w, the other
side y of the dash-pot is constantly in communication with the steam
jacket of the engine by means of a pipe q. When the click P moves
forward and engages the dash-pot rod T, steam is admitted through the
passage u to the side x of the dash-pot, and counterbalances the steam
on the other side y of the piston p, but as soon as the click P is disen-
gaged from the rod T, the slide valve w is raised, closes the admission
steam through the said passage u and opens the discharge passage v; the
steam then passes out from the side y of the said dash-pot, and the steam
in the side x of the said dash-pot being no longer counterbalanced drives
on the piston p and rod T, and closes the admission valve of the
engine.

page_text: working of the admission and exhaust valves within the said cylinder.
B is the valve rod; m the crank upon the end of the said rod; S is a
support of the said rod and crank. Behind the crank m is attached a
disc or thin plate n, the part i, i, of which plate represents exactly the
admission valve I (Figure 3). Upon the support 8 is attached a
piece n¹, the end j, j, of which represents exactly the steam port.
.
It will be readily understood that from this arrangement the part i, i¹,
will move upon the piece j, j', whenever the corresponding valve of the
engine has motion imparted to it, and the said part i, i¹, will indicate
exactly the motion of the said valve inside the engine, and show any
defect in the working of the same.
Figures 19 and 20 represent in vertical section and horizontal section
respectively a modification in the construction of the admission cam
frame herein-before described, in reference to Figures 1, 2, 3, and 4 of
the Drawings. According to this arrangement the said cam frame is :
provided with friction rollers G, G', against which the cam O acts. The
clicks P, P¹, in this case are forked at the joints so as to leave place for
the said rollers G, G¹.
Having now described the nature of this Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do
not confine myself to the precise details herein-before described and
illustrated in the accompanying Drawings, as the same may be varied
without departing from the nature of the said Invention.
But I claim as the said Invention of "Improvements in Steam
Engines,"
2
Firstly. The mode of opening the admission and exhaust valves
herein-before described and illustrated in the accompanying Drawings,
that is to say, by means of two cams affixed on the governor spindle of
the engine in such relative positions one to the other that steam will be
admitted into the cylinder up to eight tenths of the stroke of the piston a
when the governor is in its lowest position, the motion of such valves
being dependent upon that of the governor, so that should any accident
happen to the gear which drives the governor and cause it to stop, the
engine instead of racing away at a dangerous speed will be stopped at
once.
Secondly. The mode of releasing or disengaging the dash-pot rods
from the catch pieces on the clicks of the admission
בר
frome

page_text: essentially as herein-before described and illustrated in the accom-
panying Drawings, that is to say, by means of trip tails or curved arms
formed on the said clicks, the said trip tails or arms being caused to
come in contact with and be actuated by rollers suspended directly to
the governor.
Thirdly. The construction and arrangement of the exhaust valves in
the cylinder covers, essentially as herein-before described and illustrated
in the accompanying Drawings, the said valves being made to form a
moveable part of the ends of the cylinder.
Fourthly. The construction and arrangement of the admission valves
in the cylinder covers, essentially as herein-before described and illus-
trated in Figure 3 of the accompanying Drawings. Also the construction
and arrangement of the cylinder and admission valves, herein-before
described and illustrated in Figures 6 and 7 of the accompanying
Drawings.
Fifthly. The apparatus herein-before described and illustrated in
Figures 17 and 18 of the accompanying Drawings for exhibiting on the
outside of the cylinder the motion of the admission and exhaust valves
of the said cylinder, such apparatus being constructed and combined
essentially as described.
Sixthly. The adaptation and the combination or arrangement of parts
for driving back the dash-pot rods and closing the admission valves upon
the release of the said dash-pot rods from the catch pieces of the clicks,
essentially as herein-before described and illustrated in the accom-
panying Drawings, whether metallic springs or the action of steam be
used to actuate the said dash-pot rods.
In witness whereof, I, the said Hunter Henry Murdoch, have here-
unto set my hand and seal, this Twenty-first day of November,
in the year of our Lord One thousand eight hundred and seventy-
three
Witness,
B. WILLCOX,
His clerk.
H. H. MURDOCH. (L.S.)