An Improved Steam Engine.
Year: 1888

page_text: Date of Application, 19th Dec., 1888
Complete Specification Left, 12th. Aug., 1889-Accepted, 14th Sept., 1889
PROVISIONAL SPECIFICATION.
An Improved Steam Engine.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents do hereby declare the nature of this invention (a communication to me from
abroad by The Dake Engine Manufacturing Company (Incorporated) of Grand
Haven, in the County of Ottawa, and State of Michigan, United States of America),
do hereby declare the nature of this Invention to be as follows:-
This Invention relates to the class of double reciprocating square piston engines
such as shewn and described in Letters Patent of the United States No. 363, 368,
granted to William F. Dake, May 24th 1887.
The object of the present invention is to increase the efficiency of such engines, and
to simplify and improve their construction.
Reference is to be had to the accompanying drawings forming part of this specifi-
cation in which figure 1 is a front view of the improved engine with the cover
removed and the steam chest in section. Figure 2 is a sectional view of the same on
line xx figure 1. Figure 3 is an inner face view of part of the cover. Figure 4
is a face view of the piston with the cover removed and parts in section. Figure 5
is an elevation of the engine with parts broken out. Figure 6 is a sectional plan view
of the same on line y y figure 5. Figure 7 is a plan view of the casing, the steam
chest being removed, and figure 8 is a sectional plan view of the steam chest on line z-z
figure 5.
Similar letters of reference indicate corresponding parts in all the figures.
The casing A has a chamber A¹ in which is fitted to slide to and fro horizontally a
rectangular piston B having a chamber B¹ in which is fitted to slide vertically an
inner piston C mounted at its centre on a crank pin D passing through a slot in the
back plate of the piston B and secured to a crank disc E fast on the end of the main
shaft F. Within the steam chest G is fitted a four-way valve H which is adjusted
by a handle H', or by other means. I is the steam inlet pipe, I¹ the exhaust pipe
respectively leading to and from the valve chest G. By the valve H, the steam inlet
pipe I may be connected either with the port a or the port b in the steam chest and
the exhaust pipe 11 with the said port a or b. The ports a and b are formed in the
steam chest G and lead to the ports c and d formed in the casing A and the ports c
and d connect with the channels e and frespectively formed in the outside of the
cover J. The channel e leads to a central port 9 in the cover J opening against the
face of the inner piston C, and the channel leads to an annular port h also formed
on the inside of the cover J around the port g and opening against the face of the
inner piston C.
g
The central port 9 and the annular port are adapted to communicate alternately
with the ports and 3 formed in a circle in the inner piston C and of which the
port i leads through a channel to an opening k formed in the left side of the said
piston B and leading to the chamber A¹ of the casing A. The port leads to the
channel opening into the chamber B' of the piston B at the top of the inner
piston C. The port 2 is similar to the port i and leads to a channel which com-
municates with an opening k¹ formed in the right end of the piston B and leading to
the chamber A¹ of the casing at the right of the piston B. The port ³ is similar to the
port and leads to the channel 17, opening into the chamber B¹ of the piston B at
the bottom of the inner piston C.
In the back of the piston B are formed vertical recesses into which fit packing
plates K and K¹ pressed against the rear wall of the casing A by live steam entering
between the said plates K and K' and the piston B through openings L and L' con-
nected with each other by a groove L³ in the top of the casing A, as shown in

page_text: figure 7. The groove L' communicates with the openings L³ and L* formed in the
steam chest G, and leading into the ports a and b so as to admit live steam into the
groove L² thence through the openings L and L between the packing plates K
and K' and piston B, so as to form a steam-tight packing. The inner piston C is
provided at its ends with the packing plates N and N₁ of any approved construction,
and pressed against the end walls of the piston B by any suitable means, so as to form
a steam-tight packing between the said inner piston C and the piston B. The wear
of the latter is taken up by a plate O upon which the bottom of the said piston B
rests, said plate O being supported by an adjustable wedge plate P whose inclined
surfaces P2 slide on corresponding inclines A² formed on the bottom of the casing A.
The wedge plate is adjusted longitudinally by set screws P¹ bearing against its ends.
By this means the plate O is pressed upward into firm contact with the bottom of the
casing B.
The operation is as follows-When the engine is in the position shown in figure 1,
steam passes from the inlet pipe I through the valve H into the ports a cand e into
the central opening g.
From the central opening it passes into the port i of the
inner piston C, and through the channel and the opening k into the left end
of the chamber A¹, thus moving the piston B from left to right.
Rotary motion is thus imparted to the main shaft. F through the medium of the
inner piston C, the crank pin D and the disc E. The inner piston c in moving causes
the port to coincide with the central opening g, so that live steam now passes
through the ports and into the chamber of the piston B on top of the piston C
moving the latter downwards whereby a new impulse is given to the driving shaft F
through the crank pin D. On the further movement of the pistons B and C as above
described the central port 9 coincides with the port 2, so that the live steam passes
through the channel and the opening k¹ into the chamber A' at the right end of the
piston B, so that the latter is now caused to perform its return stroke from right to
left in casing A. By the further movement of the pistons B and C the central port g
now coincides with the port and live steam enters through the channel to the
chamber B at the bottom of the inner piston C and presses the inner piston O
upward, at the same time assisting the piston B in its movement to the left.
g
The exhaust steam from the left of the chamber A' passes through the opening k,
the channel and the port i to the annular port h in the cover J thence through the
channel port d and 6 through the valve H to the exhaust pipe I'. The exhaust at
the upper end of the chamber B' passes through the channel 1 and the port to the
annular port through which it passes to the exhaust pipe I', as above described in
reference to the port i.
h
2.
The exhaust from the right of the chamber A¹ takes place through the opening k¹,
the channel and the port and the annular port h, and the exhaust from the bottom
of the chamber B takes place through the channel and the port and the annular
port h, from which the steam passes to the exhaust pipe I' as above described.
It is understood that the movement of the inner piston C brings the ports i, 1,
and alternately to coincide with the central port g, and at the same time the exhaust
ports exhaust through the annular port h.
When the valve His reversed the courses of the live and exhaust steam are reversed
the motion being the same as above described but in the reverse direction.
By the construction of this engine, there are no valves whatever except on the face
of the inner piston C against the cover plate J, and no eccentric or other devices are
needed to operate the valve, the action being directly upon the piston C and cover J
to admit and cut off steam at the proper time to give continuous motion to the
engine.
Dated this 19th day of Decembar 1000
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.

page_text: COMPLETE SPECIFICATION.
An Improved Steam Engine.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent Agents
do hereby declare the nature of this invention (a communication to me from abroad
by The Dake Engine Manufacturing Company (Incorporated) of Grand Haven, in the
County of Ottawa, and State of Michigan, United States of America, 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 the class of double reciprocating square piston engines
such as shewn and described in Letters Patent of the United States No. 363, 368,
granted to William F. Dake, May 24th 1887.
The object of the present invention is to increase the efficiency of such engines, and
to simplify and improve their construction.
Reference is to be had to the drawings left with my provisional specification in
which figure 1 is a front view of the improved engine with the cover removed and
the steam chest in section. Figure 2 is a sectional view of the same on
line figure 1. Figure 3 is an inner face view of part of the cover. Figure 4
is a face view of the piston with the cover removed and parts in section. Figure 5
is an elevation of the engine with parts broken out. Figure 6 is a sectional plan
view of the same on line y y figure 5. Figure 7 is a plan view of the casing, the
steam chest being removed, and figure 8 is a sectional plan view of the steam chest
on line z-z figure 5.
Similar letters of reference indicate corresponding parts in all the figures.
The casing A has a chamber A¹ in which is fitted to slide to and fro horizontally a
rectangular piston B having a chamber B¹ in which is fitted to slide vertically an
inner piston C mounted at its centre on a crank pin D passing through a slot in the
back plate of the piston B and secured to a crank disc E fast on the end of the main
shaft F. Within the steam chest G is fitted a four-way valve H which is adjusted by
a handle H, or by other means. I is the steam inlet pipe, 11 the exhaust pipe
respectively leading to and from the valve chest G. By the valve H, the steam inlet
pipe I may be connected either with the port a or the port b in the steam chest and
the exhaust pipe I¹ with the said port a or b. The ports a and bare formed in the
steam chest G and lead to the ports c and d formed in the casing A and the ports c
and d connect with the channels e and respectively formed in the outside of the
cover J. The channel e leads to a central port g in the cover J opening against the
face of the inner piston C, and the channel leads to an annular port h also formed
on the inside of the cover J around the aperture g and opening against the face of
the inner piston C.
The central port g and the annular port h are adapted to communicate alternately
with the ports i¹³ and 3 formed in a circle in the inner piston C and of which
the port i leads through a channel to an opening k formed in the left side of the
said piston B and leading to the chamber A of the casing A. The port i¹ leads to
the channel opening into the chamber B¹ of the piston B at the top of the inner
piston C. The port is similar to the port i and leads to a channel which com-
municates with an opening k¹ formed in the right end of the piston B and leading to
the chamber A¹ of the casing at the right of the piston B. The port is similar to the
port and leads to the channel 7, opeinng into the chamber B¹ of the piston B
at the bottom of the inner piston C.
In the back of the piston B are formed vertical recesses into which fit packing
plates K and K₁ pressed against the rear wall of the casing A by live steam
entering between the said plates K and K' and the piston B through openings L
and L connected with each other by a groove L³ in the top of the casing A, as
shewn in figure 7. The groove L communicates with the openings L³ and L*
formed in the steam chest G, and leading into the ports a and b so as to admit live
steam into the groove L' thence through the openings L and L¹ between the

page_text: packing plates K and K' and piston B, so as to form a steam-tight packing. The
inner piston C is provided at its ends with the packing plates N and N¹ of any
approved construction, and pressed against the end walls of the piston B by any
suitable means, so as to form a steam-tight packing between the said inner piston
and the piston B. The wear of the latter is taken up by a plate O upon which
the bottom of the said piston B rests, said plate O being supported by an adjust-
able wedge plate P whose inclined surfaces P2 slide on corresponding inclines A
formed on the bottom of the casing A. The wedge plate is adjusted longitudinally
by set screws P' bearing against its ends. By this means the plate O is pressed
upward into firm contact with the bottom of the casing B.
The operation is as follows-When the engine is in the position shown in figure 1,
steam passes from the inlet pipe I through the valve H into the ports a c and e into
the central port or opening g. From the central port 9 it passes into the port i
of the inner piston C, and through the channel and the opening k into the left
end of the chamber A¹, thus moving the piston B from left to right.
Rotary motion is thus imparted to the main shaft F through the medium of the
inner piston C, the crank pin D and the disc E. The inner piston C in moving
causes the port to coincide with the central opening g, so that live steam now
passes through the ports and into the chamber of the piston B on top of the
piston C moving the latter downwards whereby a new impulse is given to the driving
shaft F through the crank pin D. On the further movement of the pistons B and
as above described the central port g coincides with the port 2, so that the live steam
passes through the channel and the opening ¹ into the chamber A¹ at the right end
of the piston B, so that the latter is now caused to perform its return stroke from
right to left in casing A. By the further movement of the pistons B and C the
central port 9 now coincides with the port 3 and live steam enters through the
channel to the chamber B' at the bottom of the inner piston C and presses
the inner piston Cupward, at the same time assisting the piston B in its movement
to the left.
The exhaust steam from the left of the chamber A¹ passes through the opening
the channel and the port i to the annular port h in the cover
thence through the channel port d and through the valve H to the exhaust
pipe I. The exhaust at the upper end of the chamber B¹ passes through the
channel and the port ¹ to the annular port through which it passes to the exhaust
pipe 1', as above described in reference to the port i.
The exhaust from the right of the chamber A' takes place through the opening k¹,
the channel and the port and the annular port h, and the exhaust from the bottom
of the chamber B₁ takes place through the channel and the port 3 and the annular
port h from which the steam passes to the exhaust pipe I' as above described.
It is understood that the movement of the inner piston C brings the ports i, ³,
and alternately to coincide with the central port 9, and at the same time the exhaust
ports exhaust through the annular port h.
When the valve H is reversed the courses of the live and exhaust steam are
reversed, the motion being the same as above described but in the reverse direction.
By the construction of this engine, there are no valves whatever except on the
face of the inner piston C against the cover plate J, and no eccentric or other devices
are needed to operate the valve, the action being directly upon the piston C and
cover J to admit and cut off, steam at the proper time to give continuous motion to
the engine.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In an engine, the combination, with a casing and a piston reciprocating therein,
a second piston arranged within and having a reciprocating motion at right angles
to the line of movement of the first named piston, the outer face of the said second
piston forming a valve for operating both pistons, substantially as described.

page_text: 2. In an engine, the combination, of a casing having a central port or opening
in the inner surface of its front plate, a piston reciprocating therein, a second
piston arranged within and having a reciprocating motion at right angles to the
line of movement of the first named piston, and provided with ports on its outer
face, said ports being arranged in a circle and operating over the said central port
or opening of the casing, substantially as herein shown and described.
3. In a steam engine of the class described, the combination, with an inner piston
having steam ports arranged in a circle, of a cover having a central opening or
port and an annular opening or port with which the said ports are adapted to
coincide, substantially as shown and described.
4. In a steam engine of the class described, the combination, with an inner piston
provided with the ports i, ¹, 2, and 3, of an outer piston having the openings k
and connecting with the said ports i and and a casing surrounding the said
outer piston, substantially as shown and described.
5. In an engine of the class described, the combination with the casing and
steam chest, of a piston fitted to slide horizontally in the said casing, packing plates
held at the back of said piston, and pressed against the back of the said casing
by live steam, passing from the steam chest through suitable openings in the casing
between the said packing plates and the said piston, substantially as shown and
described.
1000
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.