Year: 1888

page_text: CHARLES H. STEEN, and MILTON MCDONALD of Topeka, in the County of Shawnee,
and State of Kansas, and of Streator in the County of La Salle and State of Illinois,
gentleman, 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 :—
This invention has relation to pistons for steam and other engines, and is generally
applicable to pistons which are provided with packing rings, which rings have to be
set out occasionally to keep them tight.
Heretofore the piston packing has been set out with springs, and attempts have also
been made to set the rings out by steam from the cylinder, which have been more or
less successful, but has not attained satisfactory results for the reason that the parts
were liable to become loose and rattle, not only being very annoying but dangerous.
Therefore to overcome these objections and to produce a piston that will auto-
matically control the pressure of its packing against the walls of a cylinder by the
steam fluid or air in the cylinder are the objects of our invention.
To these ends our invention consists in forming the piston head in sections, and
provided each section with an annular recess beneath the bearings of the rings, said
recesses communicating with the steam in the cylinder and with annular recesses in
the periphery of the bearings for the piston rings, said steam or fluid having access
to said chambered recesses through the front head and follower respectively, by means
of an adjustable plug provided with an inlet and exit port, said plug being tightly
screwed into its seat so that it will not turn only when desired by means of a socket
wrench or suitable instrument all of which will be more fully hereinafter described.
In the drawings hereto annexed.
Figure 1 is a section through the piston and part of the cylinder and head.
Figure 2 is an enlarged sectional view of the regulating plug or valve, and
Figure 3 is an end view of the piston showing the position of the plugs.
A further object of our invention is to construct a piston that will be light in
weight, simple in construction, the principal object being to set out the packing
rings by steam or fluids and to control the said steam of fluids so that the pressure
will not be as high in the recesses in the piston as it is in the cylinder.

page_text: The piston is composed of the two discs A A, which are similar in construction s
the description of one will describe the other. The disc A is provided on one side
with an annular recess B, that extends from near its periphery towards the pistor
rod E, this recess may extend nearly to the rod, as shown in dotted lines, which will
make the piston lighter in weight. Between the periphery of and forming one side
of the recess B, is an annular groove D having two or more passages d, that lead from
the recess into the groove F, formed by placing one disc upon the other and a
follower C, upon the outer disc. The groove F, contains the packing rings a a, that
may be of any suitable material.
When these discs and followers are secured upon the piston rod, in this instance by
a nut H screwed on the end of the rod, they form two recesses or chambers and two
grooves for the packing rings.
Leading from the cylinder, through the disc on one side and the follower on the
other of the piston, is a port b, which is enlarged to receive a plug or valve G, which
is provided with a port g, drilled through it or cut in its periphery as shown in
figures 1 & 2. This port does not register with the port b, so what when tho plug is
down upon its seat, the steam cannot pass through to the packing. We have shown
three plugs or valves but it is evident that one upon each side of the piston could be
used and have the same effect.
Opposite the plugs G, and in each head of the cylinder are screw plugs I upon the
removal of which a wrench may be inserted to adjust the plug valves G.
The adjustment of the plug and operation of the device is as follows; the plugs
are screwed down to their seats and then screwed very slightly in the opposite
direction, thus leaving a very small opening for the steam to pass, the amount of
opening will be governed by the pressure of steam that the engine is operated
with, the higher the steam pressure the smaller the opening.
Steam being admitted to the cylinder will pass through the ports g and b, into the
recess B, and through the port d into the groove F, and gradually increasing in
pressure and setting out the packing on that end of the piston but before the pressure
acting on the packing rings can reach that in the cylinder, the piston has reached the
end of the stroke and the steam from that side of the piston is exhausted which
permits the steam or a greater part of it to be exhausted from the recess and lower the
pressure upon the packing rings until the next stroke of the engine.
This operation occurs alternately on each side of the piston as it received and
exhausts the steam at each stroke.
It follows that by thus controlling the steam acting upon the packing rings, the
objection to using steam to keep the rings in contact with the cylinder is overcome,
for in using steam for this purpose, especially at a high pressure the rings would
be set out so hard that a great part of the energy of the engine was lost on over-
coming the friction thus produced.
Having now particularly described and ascertained the nature of our inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
In a piston head, the combination of a recessed disc, and a follower, with packing
rings, a seat having a port leading from the cylinder into the recess, and a tight screw
plug or valve for controlling said port, the plug having a port outside of its axial line
substantially as described.
Dated this 30th day of October 1000