AN IMPROVED ARRANGEMENT OR CONSTRUCTION OF CUT-OFF GEAR FOR STEAM ENGINES
Year: 1857

page_text: PROVISIONAL SPECIFICATION left by William Edward Newton at the
Office of the Commissioners of Patents, with bis Petition, on the
1st June 1857.-A communication.
I, WILLIAM EDWARD NEWTON,. of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "AN IMPROVED ARRANGEMENT OR CONSTRUCTION OF CUT-OFF
GEAR FOR STEAM ENGINES," to be as follows:―
This Invention, of an improved arrangement of cut-off gear for steam
engines, is intended to be employed in connection with a governor to govern a
steam engine, by effecting the cutting off of the steam nearer to the com-
mencement or termination of the stroke of the piston.
The Invention is applicable directly to the induction valve or valves of a
steam engine when separate induction and eduction valves are used at each
end of the cylinder, or to a separate "cut-off" valve arranged in the steam
pipe, or otherwise between the boiler and the steam chest, so as to act
independently of the ordinary valves which regulate the induction and eduction
of the steam to the cylinder.
The Invention consists in an arrangement of mechanism by which a valve
is caused to be detached from its lifting or opening gear, so as to permit
it to be closed, to cut off or shut the further supply of steam from the builer
to the cylinder by the agency of gravitation, or of a spring or other contrivance

page_text: properly applied at such point in the stroke of the piston as is necessary to
regulate the speed of the engine.
The cut-off valve is of the kind. known as the double or balanced puppet
valve, but valves of other kinds, it is obvious, may be used with the same cut-
off gear. The cut-off valve box is placed on the top of the steam chest, and
communicates therewith by an opening in its bottom.; the cut-off valve being
thus situated between the steam pipe leading from the boiler and the valve
box which supplies steam to the engine, the steam enters the valve box
between the two heads of the cut-off valve and is admitted to the steam chest
by lifting the cut-off valve, which is provided for that purpose with a stem that
works through a stuffing box in the top of the cut-off valve box.
The valve stem has fitted loosely to it with a sliding socket a flat plate,
whose edges incline towards each other from the top nearly to the bottom,
leaving. a small portion at the bottom parallel with the stem. This plate is
held suspended by a rod, which passes through the hollow centre shaft of the
governor, and is connected with the governor in such a manner that any increase
of velocity of the latter would cause the said rod to descend, and any diminution
of velocity would cause it to ascend, in the former case elevating the plate, and
in the latter depressing it on the valve stem. Any kind of governor, such as
the common centrifugal ball governor, or a pneumatic or other governor may
be used, provided it be applied so as to produce the proper effect on the plate
which works up and down on the valve stem, which has rigidly secured to it a
cross head, from the opposite ends of which are suspended by joints two
pendent rods, each of which carries a stud, and two springs are attached to the
cross, head to act upon the rods in such a manner as to keep the studs thereon.
in contact with the edges of the plate. Below the pendent rods are situated
two bent arms, which branch in opposite directions from. a rock shaft, which is
arranged to work in a suitable bearing in a, standard, and deriving motion
from an excentric or other suitable mechanical; means, actuated by the engine,
by which means the arm is made to, lift the pendent rods which stand above it,
and thus the valve stem is lifted, and the puppet valve is thereby opened
twice in every revolution of the engine, or once in each stroke of the piston,
said lifting and opening movement taking place as or just before the piston
arrives at the end of its stroke, to open communication between the boiler and
the steam chest ready for the induction of the steam, when the proper move-
ment of the valve, that may be employed for the induction of steam takes
place. As the valve stem is thus lifted, the studs on the pendent rods in
moving up the inclined edges of the plate are forced apart, until the pendent

page_text: rod escapes from the vibrating arm that is in operation upon it, and the cut-
off valve being unsupported, suddenly falls, and closes by its own weight, or is
caused to descend and close by the action of a spring applied above the cross
head, thus cutting off the further supply of steam.
If it be desired to apply this improved cut-off gear in connection with a
governor directly to the induction valve without using an independent cut-off,
a separate induction valve must be used for each end of the cylinder, such
valves being of the puppet, slide, or other kinds, as may be considered
preferable, and the cut-off gear being applied directly to the valve stems, or to
upright lifting rods connected by levers or other contrivances with the valves.
In such case each valve stem or lifting rod will require to be fitted with a
plate for opening the pendent rods.