IMPROVEMENTS IN METAL PACKED PISTONS
Year: 1878

page_text: LETTERS PATENT to James Jones, of Liverpool, in the County of Lancaster,
Engineer, for the Invention of "IMPROVEMENTS IN METAL PACKED PISTONS."
PROVISIONAL SPECIFICATION left by the said James Jones at the Office of
the Commissioners of Patents on the 7th December 1878.
JAMES JONES, of Liverpool; in the County of Lancaster, Engineer.
MENTS IN METAL PACKED PISTONS."
"
IMPROVE-
The object of this Invention is to so construct and arrange the packing rings and
springs of pistons for steam engines, pumps, and like apparatus that a piston shall
be obtained in which uniform pressure is maintained at all points between the
packing rings and the cylinder containing the said piston and adjustment of such
pressure facilitated. The construction and arrangement of the parts ensure
durability and allow of cheapness in construction.
In carrying my Invention into practice I employ a piston in which one plate is
made adjustable so as to be capable of being caused to approach or recede from the
fixed plate of the piston by means of set screws or their equivalents, or the piston
may be made with two movable adjustable plates. Between the said adjustable plates
or adjustable and fixed plate I place two annular packing rings L shaped in cross
section, and cut across at one or more points (preferably one) of their circumference.
Two metal springs, a greater number may be used if desired, extend around the
inside of the said packing rings, and are so curved or constructed in a zigzag or
waved form as to press the said packing rings both against the bottom and top
internal surfaces of the piston, and against the internal surface of the cylinder, and
the more effectually to ensure equality of pressure in every direction; I prefer that
the springs should be so placed that the curved or zigzag lines should cross each
other. The ends of the springs are secured to one another, or to a block or piece:
The packing rings at their point of severance are connected by a tongue piece.
In practice when the piston is first placed in its cylinder, the packing rings are a
slight distance apart to allow of the plate or plates being moved up when it is
required to compress the springs, and cause the expansion of the packing rings.

page_text: Fig. 1 is a plan view of one half of a metal packed piston, one plate or junk ring
being removed; Fig. 2, a view of the complete piston in side elevation and section,
and Fig. 3 an inside elevation showing part of duplex springs and packing rings
extended, and also the securing block. Like letters denote the same parts in all
these views.
A, bottom plate secured to the piston rod; b, top plate or junk ring; c,
fastening bolts or studs; d, d', split _ shaped packing rings, here shown slightly
beveled on the side where they abut; e, channel or grooved uniting tongue for
the packing rings, the same being secured near one end by a screw; f, f', are
the two metal springs; in this modification they are angular in the rising and
falling parts, and flat in those parts which act on the flat surfaces of the packing
rings; they are placed, as will be seen, the one within the other concentrically,
and the rising and falling parts are made to cross each other; g, securing block
with apertures therethrough into which the ends of the packing springs are placed.
When wear has taken place and it is desired to increase the tension or resilience of
the springs acting on the packing rings, the ends of the said springs are placed in
the outer apertures indicated by the dotted lines in Fig. 3, and seen in Figs.
1 and 4.
Usually a & bare metal to metal, and the springs and packing rings are so
adjusted as to fit the cylinder properly without excessive pressure and consequent
objectionable friction on the cylinder.
Fig. 5 shows in elevation the inside packing rings, duplex waved springs, and
modified securing block; d, d¹, packing rings; f, f, springs. The packing block is
here made in two pieces, the apertures for the springs being at the ends. A wedge
or the like may be used for separating the said pieces so as to increase the resilience

page_text: of the springs if desired; Fig. 6 is a top, and Fig. 7 an end view of the said
securing block.
Fig. 8 is a view similar to Figure 3, the duplex springs having less bearing on
their flat parts, and the securing block having helical springs h placed therein;
Fig. 9 is a top view of the securing block.
Fig. 10 is an inside view of packing rings and a single angular spring. The ends
of the said spring are laid or fitted into grooves in the securing block g, which is
here in two pieces so that it can be expanded, and the tension or resilience of the
spring thereby increased and made to act with greater effect on the packing rings;
Fig. 11 is a top view of the block g.
It will be obvious that the plates and the packing rings may be left slack or a
slight distance apart when passing the piston into the cylinder. It will also be
obvious that my said piston when adjusted bears on the cylinder with just sufficient
pressure, and does not practically vary with the varying pressure of steam or fluid
in the cylinder. The packing rings being entirely without angular surfaces for the
springs.
Having now described the nature of my said Invention and particularised the
same, I claim,-
Metal packed pistons constructed substantially as herein described, the parts
operating and having the functions set forth.
In witness whereof, I, the said James Jones, have hereunto set my hand and
seal, this Sixth day of June, in the year of our Lord One thousand
eight hundred and seventy nine.
TAM
LANDS
MES
JONES. (L.S.)