Improvements in Valve Gears for Steam Engines.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Valve Gears for Steam Engines.
I, JERDAN NICHOLS, of Falls Foundry, Belfast, Ireland, Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in automatic cut off gear for controlling
the admission valves of steam engines and regulating the admission of steam
where variable expansion is required. The object of the present invention is
to simplify the construction of the cut off and render the same efficient in its
operation by ensuring a direct action of the several parts.
According to this invention we mount in the slide which is actuated by the
eccentric rod a sliding catch piece of hardened steel which engages with a step
or catchplate in the trunk secured to the dashpot plunger. The trigger for
releasing the catch piece from the catchplate is mounted on a pin or stud at the
end of the trunk of the dashpot plunger, and such trigger is operated by links
from the ordinary sector gear wheels or other source.
The trunk of the dashpot is connected to the valve lever by a link mounted on
the pin or stud at the end of said trunk, so that the flattened spring rod is dis-
pensed with and the releasing or tripping trigger and the links are carried on
one and the same centre.
Dated this 25th day of March 1898.
BRIERLEY & HOWARD,
Penny Bank Chambers, Halifax,
Agents for the Applicant.
I, JERDAN NICHOLS, of Falls Foundry, Belfast, Ireland, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment:-
This invention relates to improvements in automatic cut off gear for controlling
the admission valves of steam engines and regulating the admission of steam
where variable expansion is required. The object of the present invention is
to simplify the construction of the cut off and render the same efficient in its
operation by ensuring a direct action of the several parts.
The invention consists in so constructing and combining the parts that the
flattened spring rod of the dashpot heretofore necessary is dispensed with, and
the releasing or tripping trigger and the links are carried on one and the same
centre and have direct action on the catch piece which is carried on a separate
and distinct part.

page_text: Such being the nature and object of my said invention, the following is a
complete description of same, reference being had to the accompanying drawings,
in which:
Fig. I is a sectional side elevation of the improved valve gear.
Fig. 2 is a plan view of the valve gear, a portion of the upper part being
removed.
According to this invention I mount in the slide 1 which is actuated and moved
to and fro by the eccentric rod 2 a vertical sliding catch piece 3 of hardened steel
which engages with a step or catchplate 4 in the trunk 5 secured to the dashpot
plunger 6. The trigger i for releasing the catch piece 3 from the catch plate 4
is mounted on a pin or stud 8 at the end of the trunk 5 of the dashpot plunger 6
and such trigger 7 is operated by links 10 from the ordinary sector gear
wheels 11-11 or from other source.
The trunk 5 of the dashpot plunger is connected to the valve lever 12 by a link
or links 13 mounted on the pin or stud 8 at the end of said trunk 5 so that the
flattened spring rod heretofore required is dispensed with and the releasing or
tripping trigger 7 and the links 13 may be carried on one and the same centre.
The cam like surface 14 of the trigger 7 pressing on the pins 16-16 depresses
the catch piece 3 so that the catch plate 4 and trunk 5 can pass over same, and the
spiral spring 15 tends to force the catch piece 3 outwards so that the latter is
always ready to catch behind the plate 4.
When the catch 3 engages with the catch plate 4 (see Fig. 1) the trunk 5 and
dashpot plunger 6 are moved forwards, and through the agency of the connecting
rod 13 moves the valve spindle lever 12, rotates the spindle 17, and opens the
Corliss valve in the usual manner. When the valve is sufficiently opened the
triggers 7. depress the catch 3, release the catch plate 4, and the spiral spring 18
inside the recoil cylinder 19 draws the trunk 5 into its normal position and closes
the Corliss valve.
The trigger rod 10 may be connected to the governor gear when an automatic
cut off" is required, or to a fixed bracket where a fixed "cut off" is necessary.
The herein described arrangement and construction of mechanism ensures the
connecting joint or stud 8 being outside the recoil cylinder 19, and the triggers 7
and connecting rod 13 may if desirable be carried from one and the same pin,
and the points of contact between the catch 3 and catch plate 4 are as nearly as
possible in the direct line of motion of the rod 13 in addition to dispensing with
the spring rod or joint heretofore employed inside the recoil cylinder 19.
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: :-
(1) The general construction, arrangement, and combination of parts consti-
tuting the improved valve gear as and for the purpose herein described and sub-
stantially as illustrated by the annexed drawings.
(2) The catch 3 carried in the slide 1, and the triggers 7 and rod 13 mounted
on a stud or studs on the trunk 5, all in combination as and for the purpose
herein described and substantially as illustrated by the annexed drawings.
Dated this 1st day of December 1808
JERDAN NICHOLS.
By his Agents,
Brierley & Howard,
Penny Bank Chambers, Halifax.
JERDAN NICHOLS.
By his Agents,
Brierley & Howard,
Penny Bank Chambers, Halifax.