Improvements in Corliss Valve Gear for Steam Engines.
Year: 1894

page_text: Date of Application, 1st Feb., 1894
Complete Specification Left, 9th May, 1894-Accepted, 30th June, 1894
PROVISIONAL SPECIFICATION.
Improvements in Corliss Valve Gear for Steam Engines.
We, JOHN HENRY HARGREAVES, and JOHN GEORGE HUDSON, both of
Soho Iron Works, Bolton, in the County of Lancaster, Engineers, do hereby
declare the nature of this invention to be as follows, that is to say :-
Our said invention has for its object to improve the construction or arrangement
and the operation of Corliss valve gear for steam engines.
In carrying out our invention in cases in which the valves as well as the gear
for actuating them are of the Corliss type, we have a lever on the end of each
admission valve jointed to a rod connected to the dashpot piston, and it is by action
on this rod that the valve is moved, instead of separate rod being acted on as in
some existing Corliss valve gears. The rod has fitted to slide upon it a sleeve or
tubular piece, which is screwed externally, and has fixed on it at or near its outer
end a block connected by a pair of links to a rocking lever actuated from the usual
wrist plate or in an equivalent manner, the rocking lever being either loose on the
valve spindle or having a separate axis. The sleeve block has jointed to it a
tripping lever a steel clip on which engages with a steel clip fixed upon the
rod jointed to the valve lever; and this tripping lever is formed with an arın
extending oppositely from the part to which the clip is fixed, it being by an
action on this arm that the clips become disengaged. At or near the inner end
of the sleeve there is adjustably fixed on it a ring, between which and the
dashpot piston there is placed a helical spring; and this spring by acting on
the dashpot piston and through it on the rod connected to the valve lever,
closes the valve whenever the clips become disengaged. With the arrangement
hereinbefore described it follows that the spring is compressed by the movement
of the sleeve when the latter is returning inwards from its outward valve-
opening stroke; and the spring is in consequence ready to act with adequate
force for closing the valve however early in the opening stroke the releasing of
the clips may take place.
The dashpot piston has the rod connected to it, by preference, in the following
manner. The rod has a convex head formed on it, which bears on a steel plug
screwed into the piston after the rod has been entered; and a helical spring is
applied between the head and the contracted end of a box or socket formed
on the piston to contain the rod end and spring. The spring keeps the head
of the rod against the steel plug whilst allowing the very slight angular
movement due to the connecting of the rod to the valve lever.
The tripping lever may be made to act by encountering a stop which is.
adjustable in position by a governor such action taking place during the valve-
opening stroke, the tripping-lever arm being of a form adapted for such action.
Or the tripping lever may be arranged to be acted on by a separate positive
motion derived from the wrist plate or other suitably moving part, and in this
case the arm of the tripping lever will be shaped so as to have the part of it
to be acted on, parallel to the rod connected to the valve lever. The part
acting on the tripping lever and its actuating mechanism will be arranged in
connection with a governor in a manner to act at an earlier or later period of the
stroke of the steam piston. With this arrangement the release of the clips, and
consequent cut-off of the steam can take place not only during the valve-opening
movement but even after the valve has begun to close. A more complete and
convenient control of the cut-off is thus obtained; whilst the best action of the
exhaust valves can be obtained from the wrist plate which works the admission
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page_text: valves, instead of separate gear being used for the exhaust valves as has been found
necessary in many cases.
The improved gear is easily adaptable to other than Corliss valves.
valves, instead of separate gear being used for the exhaust valves as has been four
necessary in many cases.
The improved gear is easily adaptable to other than Corliss valves.
Dated this Thirty-first day of January 1894.
COMPLETE SPECIFICATION.
Improvements in Corliss Valve Gear for Steam Engines.
We, JOHN HENRY HARGREAVES, and JOHN GEORGE HUDSON, both of
The Soho Iron Works, Bolton, in the County of Lancaster, Engineers do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, that is to say :-
Our said invention has for its object to improve the construction or arrangement
and the operation of Corliss valve gear for steam engines.
An example of our improved Corliss valve gear, with part of the engine to which
it is applied is shown on an accompanying sheet of explanatory drawings, Figure, 1,
thereof being a plan, and Figure, 2, a front elevation partly in section.
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated.
In carrying out our invention in cases in which the valves as well as the gear
for actuating them are of the Corliss type we have a lever, A, on the end of each
admission valve, jointed to a rod, B, connected to the dashpot piston, C, and it is
by action on this rod that the valve is moved instead of a separate rod being acted
on as in some existing Corliss valve gears. The rod, B, has fitted to slide upon it
a sleeve or tubular piece, D, which is screwed externally and has fixed or formed
on it, at or near its outer end, a block, D 1, connected by a pair of links, E, to a
rocking lever, F, actuated from the usual wrist plate, G, or in an equivalent manner
the rocking lever being on a separate axis, F 1, or if desired it might be loose on
the valve spindle, A. 1. To the links, E, or if preferred to the sleeve block, D,
there is jointed a tripping lever, H, a steel clip, H 1, on which engages with a steel
clip, B1, fixed upon the rod, B, jointed to the valve lever, A; and this tripping
lever is formed with or has fixed to it an arm, H 2, extending oppositely from the
part to which the clip, H 1, is fixed, being by an action on this arm that the
clips become disengaged. At or near the inner end of the sleeve, D, there is
adjustably fixed on it a ring, D2, between which and the dashpot piston, C, there
is placed a helical spring, C1, and this spring, C1, by acting on the dashpot
piston, C, and through it on the rod, B, connected to the valve lever, A, closes
the valve whenever the clips, B 1, and, H 1, become disengaged. With the
arrangement herein before described it follows that the spring, C1, is compressed
by the movement of the sleeve, D, when the latter is returning from its outward
valve-opening stroke; and the spring, C1, is in consequence ready to act with
adequate force for closing the valve however early in the opening stroke the
releasing of the clips, B 1, and, H 1, may take place.
The dashpot piston, C, has the rod, B, connected to it, by preference, in the
following manner. The rod, B, has a convex head, B2, formed on it which
bears on a steel plug, C 2, screwed into the piston, C, after the rod has been
entered; and a helical spring, C 3, is applied between the head and the contracted
end of a box or socket, C 4, formed on the piston to contain the rod end and spring.
The spring, C 3, is adjusted so as to maintain the head, B2, of the rod, B, in
contact with the steel plug, C2, during the compression of the larger spring whilst
allowing the very slight angular movement due to the connecting of the rod, B, to
the valve lever, A.

page_text: The tripping lever, H, may be made to act by encountering a stop (not shown).
adjusted in position by a governor such action taking place during the valve
opening stroke, the upper surface of the tripping-lever arm (H 2) being shaped
suitably for such action; but we prefer to have the tripping lever acted on in the
following manner. The arm, H 2, of the tripping lever, H, is shaped so as to have
the part of it to be acted on parallel to the rod, B, connected to the valve, and it
rests on one end of a blade spring, H 3, which is fixed on the top of the dashpot, C 5,
and presses it upwards depressing the arm, H, and making the clip, H 1, go into
gear when free to do so. On the top of the dashpot, C 5, there is fixed a bracket, J,.
having turning in it two bosses, J 1, each of which is formed with an eccentric
pin, J 2, and at the other side has fixed on it a toothed quadrant, J 3, which is
jointed to a rod, J 4, capable of being actuated by a governor (not shown) when
desired so as to alter the position of each pin, J 2. Centered on each pin, J 2, is a
lever, J 5, the upper end of which is adjustably connected by rods, J 6, and, J7, to
a separate eccentric (not shown) or it might be to the main eccentric (not shown).
or its rod, G 1, the motion being taken off at a suitable angle or other suitably
moving part. Each lever, J 5, when actuated moves its bottom end into contact
with the arm, H 2, of the tripping lever, H, and causes it to release the clips, B 1,
and, H 1, the action taking place at an earlier or later period of the stroke of the
steam piston accordingly as the pins, J 2, are adjusted by the governor. With this
arrangement of an independent tripping motion the release of the clips, B 1,
and, H 1, and consequent cut-off of the steam can take place either during the
valve-opening or during the valve-closing movement. A more complete and
convenient control of the cut-off is thus obtained; whilst the best action of the
exhaust valves can be obtained from the wrist plate, G, which works the admission
valves, instead of a separate eccentric and wrist plate or other gear being used for
the exhaust valves as has been found necessary in many cases.
The improved gear is easily adaptable to other than Corliss valves.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In Corliss valve gear connecting the valve lever or equivalent directly to the
dashpot piston, the spring acting on which is arranged to be compressed on the
return from the valve-opening stroke, combined with a tripping lever arranged to
be acted on by a stop adjusted by a governor substantially as and for the purposes
hereinbefore described.
2. In Corliss valve gear connecting the valve lever or equivalent directly to the
dashpot piston, the spring acting on which is arranged to be compressed on the
return from the valve-opening stroke, combined with a tripping lever arranged to
be acted on by a separate positive motion the acting parts of which are controlled
by a governor substantially as and for the purposes herein before described.
3. The connecting of the dash pot piston to its rod in the improved manner
substantially as hereinbefore described.
Dated this Eighth day of May 1894.
EDMUND HUNT,
Applicants' Agent,