Improvements in and relating to Steam Engines.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Steam Engines.
I, JAMES HAMILTON, a citizen of the United States, residing at No. 107
Brooks Street, in the City of Bridgeport, County of Fairfield, and State
of Connecticut, one of the United States of America, Machinist, 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 steam engines, but particularly refers to the certain new
and useful improvements in the construction of the slide valve and gear for operating
the same.
The main objects of my invention are, first to regulate the cutting off of the ports
without choking the exhaust, and second to so simplify and construct the valve gear
that it may be operated from a single eccentric.
In the accompanying drawings-
Figure 1 is a sectional elevation of a steam cylinder and valve chest equipped
with my improvement.
Figure 2 is a section at the line x-x, of Figure 1.
Figures 3 and 4 are detail broken sections, illustrating the adjustment of the
valve.
Figure 5 a front elevation showing my improved valve gear operatively applied
to a steam engine.
Figure 6, a detail section at the line y-y of Figure 5, and
Figure 7 a view similar to Figure 5, but showing the position of the valve gear
reversed.
Similar numbers of reference denote like parts in the several figures.
I will first describe my improvement in slide valves as follows:-
1, is the steam cylinder, 2, the piston therein, 3 the piston rod, 4 the valve chest,
cylindrical in shape, 5, 6, the ports leading from the valve chest into the steam
cylinder, 7 the steam inlet having ducts 8, 9, which lead into the valve chest,
and 10, the exhaust leading from the valve chest, all constructed in the ordinary
manner. 11, is the valve stem adapted to be operated from any suitable valve
gear (not shown), it being merely necessary to provide any ordinary swivel
connection for said stem, whereby the latter may be capable of an axial rotary
movement and a reciprocatory movement. 12, is a hand pin secured on said stem
by spline, 13.
On the stem are two valves, one for each port, 5, 6, each of said valves comprising
disks, 14, 15, and an intervening collar, 16, said disks and collar being secured
together as if made in a single piece.
The disks 14, fit within the valve chest snugly throughout their entire cir-
cumference, while the disks, 15, have steam inlets, 17 cut therein, as will be
presently set forth. With the exception of these cut-away portions said disks, 15
are snugly conformed to the valve chest. The diameter of the collars is less
than that of the disks so that between the latter there will be a narrow annular
space, 18.
From the inlets, 17, the disks, 15, are beveled inward toward their axes, as
seen at 19, whereby the space between the disks 14, 15, at that point is gradually
widened while at the same time the width of the edge of the disks 15 is gradually
increased from the point, 17, upward. It will therefore be readily understood that
when the disks, 15, are in the position shown in Figures 1 and 2, the inlets to the
ports 5, 6, will be the freest.
On the other hand, if the valve stem were turned so as to reverse the position of

page_text: the inlets, 17, as shown at Figure 4, the greatest width of the disks 15 would be
brought into play, thereby greatly choking the ports, 5, 6, and permitting steam to
enter therein only through the annular space, 18.
If the stem be turned so as to bring the inlets, 17, to a position at right angles
to that shown at Figures 1 and 2, the ports, 5, 6, will be moderately choked
and steam will enter said ports through the widened space between the
disks 14, 15.
From the foregoing it will be readily understood, that, when the stem is
turned, the disks, 15, will present their varying widths to the ports, 5, 6, thereby
normally choking the latter to a greater or lesser degree, as the case may be.
It will also be understood, that the beveling of the disks, 15, from the steam inlet
point 17, affords a space between the disks, 14, 15, of varying widths, and that the
wider such space immediately over the ports 5, 6, the more freely is steam admitted
within said ports.
In Figure 1, the port, 6, through which the steam is exhausted is not. choked
in the slightest degree, and when the valve stem has been reciprocated to a
position opposite to that shown, the same will be true of the port, 5.
The disks, 14, serve as absolute cut-off's between the ports 5, 6, while the disks 15
regulate the admission of steam within said ports to the steam cylinder.
The inlets, 17, may be formed by boring holes through the disks 15, the shape
and precise location of such inlets being immaterial.
My improved valve gear will be readily understood from the following
description.
1, is any ordinary frame or stand, and 2ª, a guide link secured thereto. 3ª, is
a pin within said link and adapted to slide freely therein. 4, is the valve stem
link having rigid with the back thereof the block, 5", which latter is pivoted
at 6, to the outer end of the pin, 3ª, so that it will be readily understood
that said link will rock freely on said pivotal point, 6ª see Figure 6. 7* is the
valve stem baving at its lower end a stud, 8ª, which extends laterally within
the link, 4º.
9 is the eccentric on the usual crank shaft, 10ª, and 11ª the eccentric rod
pivoted at 12, to one end of the link 4ª, so that it will be clearly seen that the
reciprocation of said rod will cause the link, 4, to rock on the point, 6.
13 is
the usual hand lever, pivoted at 14", to the lower part of the frame, and 15ª is a
connecting bar whose ends are respectively pivoted at 16, to said lever, and at 17*
around the pin, 3ª, said lever operating to shift the link, 4ª to and fro, for the
purpose presently explained.
18 is the usual crank rod operatively connected in the ordinary manner with
the piston rod, 19ª, and crank, but as said crank, crank rod and piston rod form no
part of my present invention, I have not illustrated their connection with each
other.
From the foregoing description it will be obvious that the pivotal point of the
valve stem link never changes with respect to said link, but on the contrary is
itself capable of being shifted within the guide link, 2º, to different vertical planes
relative to the valve stem. Therefore, if the pin 3ª, be brought into the same
vertical plane with the valve stem, there will be no motion imparted to the
latter by the rocking of the valve stem link. Also, if the lever, 13ª, be
operated to shift the valve stem link in such position that the eccentric rod
is in the same vertical plane with the valve stem, as shown at Figure 5, a
full throw motion will be communicated to said stem from the eccentric in a direct
vertical line.
On the other hand, if the lever, 13ª be operated to shift the valve stem link
in such position that the eccentric rod is at its greatest angle to the vertical
plane of the valve stem, as shown at Figure 7, a full throw motion will
be communicated to said stem from the eccentric through the medium of the
rocking link, 4...
It will, however, be readily understood that the effect of the action of the

page_text: eccentric on the valve stem when the parts are in the position shown at Figure 5
will be the reverse of the effect of the action of said eccentric in said stem when
the parts are in the position shown at Figure 7, and the valve is thereby caused to..
perform its reverse functions, whereby the piston is operated, as in the usual manner,
to reverse the engine.
Although I employ but a single eccentric and thereby do away with two
systems of valve gears and greatly simplify. the construction and operation of
the engine and increase its durability, and capacity still, I do not wish to be under-
stood as claiming broadly a single eccentric, since I am aware that the same has
been shown and described in prior publications.
The gist of my invention so far as it relates to valve gears, rests in the broad
idea of providing the valve stem link with a pivotal point, which latter never-
changes its position relative to said link, but is capable of being shifted to and fro
to positions on opposite sides of the valve stem.
In applying my valve gear to a locomotive, there would be an eccentric for
each cylinder, each eccentric being equipped with the herein-described pivoted
valve stem link, and the latter may be operated by a lifting shaft, such as
is commonly used on locomotives, or in any other manner adapted to the conditions.
of use.
Where piston valves are used my invention is admirably adapted, because the
application of power is more direct, and there is an apparent saving in the original
cost of construction and maintenance of friction, and lost motion is reduced to a
minimum since there are very few joints and connections between the eccentric and
the valve stem.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is :-
1. A slide valve for steam engines, comprising disks which cut off the steam
between the ports, and do not choke said ports, disks having steam inlets and
beveled inward from said inlets, and an annular space between said disks, substantially
as set forth.
2. In a slide valve for steam engines, the combination with the ports which lead
from the valve chest within the steam cylinder, of the reciprocatory and rotary
valves which respectively control the admission of steam to said ports, each valve
comprising two disks with a narrow annular space between them, one of said disks
serving as a cut-off between the ports and having a normal position beyond the
latter, the other disk having a steam inlet, and beveled inward from said inlet
whereby the width of the edge of said disk is varied, substantially as shown and
described.
3. The herein-described slide valve for steam engines, comprising a disk which
cuts off steam between the ports, a disk having a steam inlet and the width of
whose edge is varied, there being a space between said disks which varies in
width inversely to the width of said edge, said space converging into a narrow
annular recess between the disks at a point opposite to said inlet, said disks being
mounted on a reciprocatory and rotatory stem, the rotation of the stem affording a
means for adjusting the normal position of the disks around their axes, whereby the
varying widths of the inlet disk are brought into position to normally choke the-
ports to a greater or lesser degree, as the case may be, substantially as shown and
described.
4. In a valve gear for steam engines, the valve stem link having a pivotal rocking
point which never changes its position with respect to said link, in combination with
the valve stem loosely connected within said link, a single eccentric operatively
connected to one end of said link whereby the latter is rocked on its pivotal point,
and means for shifting the pivotal point of said link to and fro on opposite sides of
the valve stem, substantially as set forth.
5. The combination of the stationary guide link, the pin adapted to slide freely.

page_text: therein, the pivoted hand lever and operative connections between said lever and
pin, whereby the latter may be shifted to and fro within said link, the valve stem
link pivoted around said pin, the valve stem having a stud extending within the
valve stem link, the single eccentric on the crank shaft of the engine, and the
eccentric rod operatively connected to said eccentric and pivoted to one end of
the valve stem link, substantially as set forth.
A
1005
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.