Improvements in Valve Gear for Direct-acting Engines.
Year: 1893

page_text: Date of Application, 10th Oct., 1893-Accepted, 11th Nov., 1893
COMPLETE SPECIFICATION.
Improvements in Valve Gear for Direct-acting Engines.
I WILLIAM CRAIG of No. 1055 Herkimer Street, Brooklyn, in the County of
Kings, and State of New York, United States of America, Engineer, 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 :-
My invention relates to valve gear for direct-acting engines in which a main
valve actuated by the steam or other fluid for the induction and eduction of said fluid
to the cylinder on opposite sides of the piston, is under the control of a spindle or
auxiliary valve working inside of the said main valve, and connected with the
piston.
The object of my invention is to better provide for securing the valve spindle or
auxiliary valve, and the main valve which slides thereon, in their proper position
within the steam chest, and also to provide a better connection between the engine
piston and the pilot rod through which the said valve spindle or auxiliary valve is
operated by the said piston.
A practical embodiment of my invention is represented in the accompanying
drawings, in which,
Fig. 1 is a central longitudinal sectional view of the cylinder, steam chest, and
valves of an engine embodying my invention.
Fig. 2 represents a longitudinal section of the cylinder, steam chest, and main
valve, in a plane transverse to that in which Fig. 1 is taken, but showing the
exterior of the valve spindle or auxiliary valve.
Fig. 3 is a transverse section approximately in the line of Fig. 1.
Fig. 4 represents a transverse section of the pilot rod, and a plan of the plate by
which it is connected to the engine piston.
A designates the engine cylinder. The steam chest, of cylindric form, is denoted
by B, and is represented as cast with the upper end of the cylinder A. A steam
inlet port is provided in the side of the steam chest, and ports C C' lead from the
side of the steam chest to opposite ends of the cylinder A, for the transmission of
steam to the opposite sides of the engine piston D. An exhaust port 6' leads from
the side of the steam chest intermediate of the ports C and C¹.
b
The
The main valve actuated by the steam is denoted by E. It is located within the
chest B, and has a reciprocating sliding movement therein upon the vertically
reciprocating spindle F, which constitutes the auxiliary valve. The said spindle or
valve F has connected with its upper end, a rod f, which extends through a stuffing
box fat the top of the cap 3, which covers the top of the steam chest.
main valve E is provided, as usual, with ports i i¹ for conducting the steam from the
inlet port to the ports C and C, and with a suitable recess for connecting each
of said ports C and C' alternately with the exhaust port b¹. The said valve spindle
or auxiliary valve F is also provided with ports and for admitting steam to,
and exhausting it from, the opposite ends of the chest or casing B, to act on the
piston-like ends of the main valve E, to produce the necessary movement of the said
valve E within the chest or casing for induction and eduction of the steam to and
from the engine cylinder.
In order to hold the main valve in its upward position (shown in Fig. 2) against
its tendency to descend by its own weight, I provide in the auxiliary valve a
groove m, shown in Fig. 1, and dotted in Fig. 2, which runs from its exhaust port !
to its upper end, so that the upper end of the main valve is open to the exhaust, and
the latter valve will be held up by the pressure of the steam admitted below it into

page_text: the steam chest through the port k in the main valve. The construction and
arrangement of the several ports, and the operation of the valves, need no further
description here, as they do not constitute any part of the present invention, but
are well known.
To carry out the present invention, the spindle or auxiliary valve F is provided
with an elongated slot G extending centrally through it, the slot being of sufficient
length to permit its necessary vertical movement. The main valve E has also
formed through it, upon opposite sides of the spindle or valve F, elongated slots g g',
adapted to register with slot G in the said spindle or valve. The said spindle or
auxiliary valve and main valve are held, to prevent them from turning from their
proper relative positions, by means of a stationary bolt H, which extends through
their respective slots, and also through the opposite walls of the chest or casing B,
as is clearly indicated in Fig. 2. The said bolt being supported at both ends in the
steam chest, makes a substantial guide for both the main valve and the spindle or
auxiliary valve, which may be readily renewed whenever it becomes worn, and
which is not liable to become broken or otherwise disarranged.
The bottom of the spindle or auxiliary valve F, is connected by means of a pilot
rod I and catch plate K with the rod d of the engine piston D. This connection
is such as to render the removal of the pilot rod from the piston rod d simple and
convenient, without cutting away the plate or piston rod at the face of the piston
to any injurious extent, and without the removal of the steam chest E. The said
connection is made as follows:-The piston rod d is made hollow for a considerable
distance from the face of the piston D, as is common, and at the face of the
piston D the catch plate K is secured to the piston over the hollow end of the
rod d. The plate K is provided with an oblong slot k; and the pilot rod I, which is
attached to the spindle F, to be turned therewith, is provided with an oblong head i,
adapted, when turned in a direction to bring its longest diameter in a plane with
the longest diameter of the slot k, to pass readily through the slot k, but when
turned at right angles to the slot, the said elongated head i will engage the plate K
upon opposite sides of the slot k, and will thereby lock the said pilot rod in position,
with its head within the hollow piston rod d.
The slot is arranged to extend lengthwise in the direction in which the bolt H
is passed through the spindle F and main valve E, so that the said spindle, with
the pilot rod attached thereto, may be readily inserted in position, when the cap
is removed, by simply sliding the spindle with its pilot rod down through the
valve E, the said spindle being turned one quarter way around from its normal
position, in which its longest diameter crosses the longest diameter of the slot k,
and after the head of the pilot rod has been passed through the slot in the
plate K, turning the said spindle and the pilot rod back into normal position, and
locking the said parts by passing the bolt H through the elongated slots G, g,
and g. To permit the disconnection and re-connection of the pilot rod and piston,
it is only necessary to remove the cap f, and take out the bolt H, when the
spindle and pilot rod may be turned by taking hold of the rod foutside of the
said cap, and the valves may be lifted out from the steam-chest.
To prevent the piston D from working around within the cylinder A, so as to
bring the head of the pilot rod I to again register with the slot k, I provide the
interior of the cylinder A with a groove a, and set a guide stud d' in the edge of
the piston D, with its end projecting from the edge of the piston into the groove a.
The tendency of the piston D to rotate while reciprocating is very slight, so that
the wear upon the stud d' and walls of the groove a, will be inconsiderable, but it
is deemed necessary, as a matter of precaution, to provide against any possible
disarrangement of the parts.
It may be here mentioned that the rod fat the top of the auxiliary valve F,
which serves to move the valve by hand whenever necessary, being exposed to the
atmosphere, relieves the upper end of the said valve from a portion of the pressure
of the steam which would otherwise come upon it when steam is admitted to the
upper end of the steam chest, so that the pressure of the steam in the cylinder

page_text: acting against the lower end of the valve, tends to counteract the tendency of the
weight of the valve to move it prematurely from its upward position.
It is obvious that this valve gear is just as well applicable to horizontal engines
as to engines of the vertical type herein represented.
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. The combination with the steam chest, the reciprocating valve, and the longi-
tudinally reciprocating valve spindle within the hest, the valve and the spindle
being provided with registering elongated slots, a bolt extending through the
slots in the spindle and valve, and through the walls of the steam chest, and
supported at both ends in the latter, substantially as set forth.
2. The combination with the engine cylinder, the piston the steam chest, the
main valve for controlling the admission of steam to the cylinder, and a central
reciprocating valve spindle on which said main valve slides, of a pilot rod attached
to said spindle, and having an elongated head, a plate at the face of the piston
provided with an elongated slot opposite the hollow end of the piston rod, the said
slot being arranged at right angles to the normal position of the head of the pilot
rod, and means for preventing the piston, the valve-spindle, and the valve from
turning from relatively normal positions, all substantially as set forth.
Dated this 9th day of October 1893.
NEWTON & SON,
Agents for the Applicant.