Year: 1885

page_text: I, JOHN REID of Middlesborough-on-Tees in the County of York, Inspecting
Engineer do hereby declare the nature of this Invention to be as follows:-
My Invention relates to pistons employed in cylinders for transmitting steam,
gas, water or other similar fluid or liquid pressure and has for its object to give
the piston a steam, gas or water tight fit to its cylinder by a simple and efficient
method of expanding a metallic packing ring with which such pistons are usually
provided.
I prefer to adapt my Invention to a piston constructed with a cover plate or
junk ring secured to the body of the piston with a circumferential recess between
them for the reception of the packing ring and the means for expanding it, but my
Invention is not limited to this application, In order to dispense with the com-
plicated inefficient or easily deranged methods often employed for expanding the
packing ring, I expand the packing ring in the following manner. The metallic
packing is preferably in one ring divided at some part of its circumference, the line
of division taking an angle with the line of travel of the piston to prevent the
ends of the ring cutting the surface of the cylinder. In order to provide a con-
tinuous contact between the packing ring and the surface of the piston, an angle
plate or strip of metal should be fitted into a corresponding recess cut into the
circumferential edge of the packing ring so as to cover the space between the ends
of the ring at the line of division. The packing ring is provided with a circum-
ferential angular extension having an inclined surface and projecting into the
recess of the piston. This extension may be continuous throughout the whole
circumference of the packing ring or may be only provided at suitable parts of the
circumference as required. A complete ring or suitable sections of a ring with a
surface inclined to correspond to the inclined surface of the packing ring extension
fits in between the side of the piston recess and the packing ring so that pressure
applied to this wedge shaped ring or the sections of such ring tends to expand the
packing ring from the piston recess and against the surface of the cylinder. This
pressure is applied by means of spiral springs or their equivalents compressed
between the wedge shaped ring or sections and one side of the piston recess, the
said spiral springs being kept in position by any suitable means as for instance by
Price 8d1

page_text: encircling studs or pins projecting from and secured to either the wedge ring or
the side of the piston recess or webs may be cast between the sides of the piston
recess forming chambers or pockets in which the spiral springs can be enclosed in
position: The compression of the spiral springs may be adjusted from time to time
by inserting washers or distance pieces between either end of each spring and the
surface with which the end is in contact.
When the piston is employed for transmitting great pressure of a non-elastic
character such as hydraulic pressure this pressure may be utilised as an auxiliary
pressure to the compressed spiral springs before described by being conveyed to the
same wedge shaped ring or "sections of such a ring in any suitable manner as for
instance plugs provided with shanks studs, or other equivalent extensions may be
fitted into the junk ring or piston cover.

page_text: I, JOHN REID of Middlesborough-on-Tees in the County of York, Inspecting
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 pistons employed in cylinders for transmitting steam gas
water or other similar fluid or liquid pressure and has for its object to keep the
piston in steam gas or water tight contact with the internal surface of the cylinder
by a simple and efficient method of expanding a metallic packing ring with which
such pistons are usually provided.
In carrying my Invention into effect I prefer a piston as usually constructed for
steam cylinders with a cover plate or junk ring secured to the body of the piston
and a circumferential recess formed between them for the reception of the packing
ring and the means for expanding the same into contact with the cylinder walls,
this is the usual method of effecting a steam gas or water tight fit between the
piston and the cylinder but the means adopted for expanding the metallic packing
ring are often complicated inefficient or easily deranged as compared with the
means employed according to my Invention.
And in order that my Invention may be fully understood I will now proceed
particularly to describe the same and for that purpose shall refer to the accom-
panying drawings.
Figure 1 illustrates in plan a piston constructed according to my Invention and
Figure 2 is a sectional view taken on line X X of Figure 1. A is the body of the
piston and B the junk ring or cover plate secured to the body of the piston in
the usual manner so as to form the circumferential recess for the reception of the
metallic packing ring C and the means for expanding it; the packing ring C. is
preferably one ring divided at some part of its circumference to enable it to open
out the line of division preferably taking an angular direction with reference to
the line of travel of the piston as shewn in Figure 3 to avoid the internal surface
of the cylinder being cut by the ends of the packing ring-In order that the
contact between the metallic packing and the cylinder shall not be intercepted by
the space between the ends of the packing ring any suitable means may be adopted
to cover this space such as angle plate or strip of metal fitted into a corresponding
recess cut into the circumferential edge of the packing ring and extending over the
space The packing ring C. is provided internally with a circumferential angular
extension D projecting with an inclined surface into the recess of the piston this
angular extension D may be continuous throughout the whole length of the pack-
ing ring C. or may be provided at suitable parts of the circumference as required-
A complete ring E or suitable sections of such a ring with a surface inclined to
correspond to the inclined surface of the packing ring projection fits in between the
side of the piston recess and the packing ring C so that pressure applied to this
ring E or sections of such a ring causes it or them to act like a wedge between the

page_text: side of the piston and the packing ring C. which is thus expanded with great force
against the inner surface of the cylinder in which it is fitted to work. This
pressure is applied by means of compressed spiral springs F or their equivalents
provided at intervals round the piston and compressed between the wedge shaped
ring E and the junk ring B so as to exert great force these spiral springs may be
kept in a position for exerting direct pressure on the ring or segments E by any
suitable means as for instance by means of studs or pins fixed into the wedge
shaped ring E as shewn in the drawings when the compression of the spiral
springs F require readjusting to exert sufficient pressure on the wedge shaped
ring E washers or packing pieces may be inserted between either end of the spiral
springs and the surface they act upon.
When applying my Invention to a piston employed for transmitting great pres-
sure of a non-elastic character such as hydraulic pressure, this pressure may be
utilized as an auxiliary pressure to the compressed spiral springs F by being
conveyed to the wedge shaped ring E in any suitable manner as for instance by
means of plugs provided with shanks studs or other equivalent extensions fitted
into the junk ring or piston cover and extending through to the ring E.
Having now particularly described and ascertained the nature of my Inven-
tion and in what manner the same may be carried into effect what I claim is:-
-
In pistons the combination of a packing ring having an internally projecting
inclined projection or inclined projections and a wedge shaped ring or sections of a
ring actuated by the direct pressure of spiral springs or their equivalents sub-
stantially in the manner and for the purpose hereinbefore described with reference
to the accompanying drawings.