Improvements in Apparatus for Actuating "Corliss" and other Spring-closed Valve Gear for Steam Engines.
Year: 1896

page_text: Date of Application, 19th Sept., 1896
Complete Specification Left, 15th Feb., 1897-Accepted, 10th Apr., 1897
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Actuating "Corliss" and other
Spring-closed Valve Gear for Steam Engines.
We CHARLES SCOTT, and HENRY HODGSON, of Guide Bridge Iron Works, near
Manchester, in the County of Lancaster, do hereby declare the nature of this
invention to be as follows:-
"
The object of our invention is to enable the "Corliss or other spring closed
valve gear to be used for cutting off the steam from zero to seven eighths of the
stroke.
As is well known the ordinary "Corliss" gear is limited in its range of
"cut-off" to about one half stroke of the engine, as the point of release of the
"trip gear" must take place whilst the excentric operating the gear is moving in
one direction, whereas with our arrangement of gear, the release can take place
after the excentric has passed the centre and is making the return stroke.
The arrangement by which we propose to effect this object is as follows.
The "dashpot-cylinder" and its adjuncts are mounted upon a slide which is
moved to and fro on a bed plate by the ordinary excentric rod, the spring piston
being also connected to the said slide by a stud passing through a slot in the
"dash-pot cylinder."
On each side of this spring piston is a coiled spring, which springs act against
the two "dash-pot" pistons which are connected to the "Corliss valve levers by
valve rods provided with a ball and socket joint. Each valve rod works in a
tube or trunk attached to the piston the said tube or trunk sliding through a
bracket which carries the die or detent which holds and releases the "dash-pot"
piston.
These dies or detents are raised at the proper time to effect the "cut-off" by
means of short toes or tappets attached to releasing levers which are acted by the
"trip" excentric rod connected to the "tripping-lever." On the upper part of this
lever is a sleeve which is connected by adjustable rods to the ends of the two releasing
levers before mentioned, so that the reciprocation of the "tripping lever" by its
excentric releases the dies or detents at the desired portion of the stroke (according
as the adjustable rods may be set) allowing the springs to close the steam admission
valves.
The sleeve on the "tripping-lever" is connected by a link and bell-crank
lever to a rod from the governor, which alters the position of the sleeve on the
"tripping-lever" and thus adjusts the "cut-off" to the increasing or diminishing
speed of the engine.
In a modification of our arrangement we use a two-armed lever to work each
"Corliss" valve. One arm of the lever is connected to the valve rod, the "dash-pot"
pistons being reversed, and the two ends of the "dash-pot" cylinder forming the
abutments for the springs. The eccentric rod is attached to a sliding block to which
are also pivotted the adjustable rods connected to the other arms of the valve levers.
The "trip" action is carried by and acts on these adjustable rods (instead of on the
ends of the trunks as in the former case) the releasing levers being connected by links
to a sliding bar or rod acted upon by the governor.
Dated this 18th day of September 1896.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicants.

page_text: Improvements in Apparatus for Actuating "Corliss "
Spring-closed Valve Gear for Steam Engines.
and other
We CHARLES SCOTT, and HENRY HODGSON, both of Guide Bridge Iron Works,
near Manchester, 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 :-
The object of our invention is to enable the "Corliss " or other spring-closed
valve gear to be used for cutting-off the steam from "zero" to seven eighths of
the stroke.
As is well known the ordinary "Corliss "gear is limited in its range of "cut-off"
to about one half stroke of the engine, as the point of release of the "trip: gear "must
take place whilst the excentric operating the gear is moving in one direction, whereas,
with our improved arrangement of gear, the release can take place after the excentric
has passed the centre, and is making the return stroke.
The arrangement by which we propose to effect this object (and which forms the
subject of our invention) will be readily understood on reference to the annexed sheet
of drawings and the following explanation thereof.
Fig. 1 on the drawings is a vertical transverse section, Fig. 2 a vertical longitudinal
section, and Fig. 3 a side elevation of so much of the valve gear of a "Corliss"
engine as is necessary to illustrate our invention.
The "dash-pot" cylinder a and its adjuncts are mounted upon a slide bed cabove
a slide 6 which is moved to-and-fro on the bed plate e by the ordinary excentric rod d,
"the spring piston e being also connected to the said slide 6 by a tongue f-passing
through a slot g in the dash-pot" cylinder a.
On each side of this spring piston e is a coiled spring hand h* which act against
the two "dash-pot" pistons i and which latter are connected to the "Corliss"
valve levers and * by valve rods and each provided with a ball-and-socket
joint.
Each valve rod works in a tube or trunk m or m* attached to its respective piston,
the said tube or trunk sliding through a bracket n or n which carries the die or
detent o or which holds and releases the dash-pot" piston.
These dies or detents o o* are raised at the proper time to effect the "cut-off"
by means of short toes or tappets p attached to releasing levers 99x (Fig. 3)
which are acted upon by the "trip excentric rod connected to the "tripping-
"lever" 5.
On the upper part of this levers is a sliding sleeves which is connected by
adjustable rods and * to the ends of the two releasing levers 7 and 4* before
mentioned, so that the reciprocation of the "tripping-lever" a by its excentric (not
shewn on the drawings) releases the dies or detents o and ox at the desired portion
of the stroke (according as the adjustable rods t and may be set) allowing the
springs or h* to close the steam admission valves. In the position shewn at
Figs. 2 and 3 the ordinary excentric rod d is supposed to be moving in the direction
of the arrow, the-valve connected to the lever k will therefore be opening, anl that
connected to the lever kx will be shut off.
"The sleeve on the "tripping-lever" is connected by a link u-and bell-crank
lever to a rod w from the governor, which alters the position of the sleeve * on the
tripping levers and thus adjusts the "cut-off" to "the increasing or diminishing
speed of the engine.
It will be seen that the "spring" piston e being acted upon directly by the ordinary
excentric rod d and acting by coinpression of the springs h and h* upon the "dash-

page_text: pot" pistons i and ** there is a constant or equal compression of the said springs
whether the "cut-off" takes place at an early or late portion of the engine's stroke.
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" or other spring-closed valve gear, connecting the valve levers (or
their equivalent) directly to the "dash-pot" pistons by valve rods provided with ball
and socket joints and working in sliding tubes or trunks, the spring piston being
acted upon directly by the ordinary excentric rod, and acting by compression.
of the springs upon the said "dash-pot" pistons, substantially as described and
illustrated.
2. In "Corliss" or other spring-closed valve gear of the hereinbefore described
class the combination of a "trip-lever" excentric and rod, oscillating "trip" lever,.
sliding sleeve thereon controlled by the governor, and connected by adjustable links to
the releasing levers which act directly upon the dies or detents which hold and release
the "dash-pot" piston, substantially as described and illustrated.
Dated thi. 1141
1907
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicants.