Improvements in Mechanism for Adjusting Piston and other Packing Rings.
Year: 1893

page_text: Date of Application, 20th Nov., 1893
Complete Specification Left, 22nd Feb., 1894-Accepted, 24th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Mechanism for Adjusting Piston and other
Packing Rings.
I, RICHARD JOSEPH FIELD of 375 Cowbridge Road, Cardiff, in the County
of Glamorgan, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in mechanism for adjusting piston and
other packing rings and the object of it is to provide more perfect means than
those hitherto used or proposed to be used for adjusting the outward resilience
or pressure of the rings. It is applicable to any convenient form of known
packing ring.
In applying it to an ordinary flat ring, a pair of lugs projecting from the
inner face of the ring equidistantly from the split, are provided. Through these
lugs make oblong shaped holes. Passing through these holes are bent bars,
one end being enlarged into a wedge-shaped form and projecting at equal distances
from the centre of the bar, so as to slide easily between the junk ring and the
flange of the piston. In other words these bars are in the form of a pair
of shaped pieces, the inner sides being tapered in the form of a wedge as
before described, and between these wedge-shaped ends and the projecting
lugs on the ring, flattened spiral springs are placed, these springs forcing the
wedge-shaped ends towards each other and the lugs on the ring away from each
other. The springs are compressed and the ring, consequently, expanded by the
action of a sliding wedge piece working between the wedge-shaped ends before
described. This wedge piece is bored through its centre and screwed, a screwed
pin passing through the centre of the wedge-piece, the point of the screw fitting
into a hole in the lower flange of the piston, a collar upon the screw working
up against and recessed into the face of the junk ring, the end of the screw
passing through, a nut being placed on the outside of the pin for the purpose
of locking the screw after adjustment. The end of the pin is made square to
receive a key. Instead of an ordinary locking nut, a ratchet wheel with spring
or other catch may be employed to prevent its getting loose. A controllable
opening is made in the cylinder cover, through which the adjusting key is passed.
This opening may consist of a nipple and cap. When a jacketted cylinder cover
is used, the tubular part of the nipple passes through both flanges of the cover
and is screwed steam-tight in each to prevent the escape of steam. On the
outside of the nipple, indicator marks are engraved on its upper surface, an index
being attached to the adjusting key for the purpose of showing the extent that
the rings are expanded.
In the case of large piston rings, more than one of my arrangement can be
applied.
Dated this 20th day of November 1893.
PHILLIPS & LEIGH,
Agents for the Applicant.

page_text: Improvements in Mechanism for Adjusting Piston and other
Packing Rings.
I, RICHARD JOSEPH FIELD, of No. 375 Cowbridge Road, Cardiff, in the
County of Glamorgan, 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 improvements in mechanism for adjusting piston and
other packing rings and the object of it is to provide more perfect means than
those hitherto used or proposed to be used for adjusting the outward resilience
or pressure of the rings.
The invention consists essentially of the combination of a double wedge device,
a spring compressible and extensible between the outer face of the said device
and the opposite face of an abutment on the ring, both spring and wedge acting
in a direction concentric with the ring, and adjusting mechanism by means of
which one member of the double wedge device can be moved over the other of
them in such a way as to either compress or free the spring, according to the
direction of such motion. There may be combined with this mechanism, a visible
scale and index of adjustments.
There are, of course, numerous forms in which the combination specified in
generic terms in the preceding paragraph, can be embodied, but my invention
does not consist in the specific form of the combination but in the combination
itself in any form. For that reason, the accompanying figures are illustrations
of a form only of my invention, that which it takes in being applied to a piston
ring. I have chosen this form of it for illustration because a piston ring and
its duty are so familiar and because such illustration exemplifies all the operative
features of the invention. The piston illustrated is not a large one and for that
reason there is only one of the combinations shewn as applied to it. As many
of the combinations in question may be applied to any particular case as the
dimensions of the latter
render necessary.
may
Figure 1 is a plan of a piston fitted with my invention, omitting the junk ring.
Figure 2 is a side elevation, partly in section.
Figure 3 is a vertical section taken on the line 3-3 of Figure 1 and includes the
adjusting mechanism and the adjacent portion of the cylinder cover.
Figure 4 is a detail thereof.
с
a is the body of the piston. b, bare the two outer piston rings, and c is the inner
one. d is the junk ring. All these parts may be of any construction. They do
not form any part of the present invention.
C
e, e are a pair of blocks adapted, in respect of size or by any other means, to
slide freely within the inner piston ring c in a direction concentric with it. In the
case illustrated, these blocks slide in the concentric channel between the piston
ring and the internal ring f, their sides being shaped to the same radii
respectively, as clearly illustrated in Figure 1, and their thickness equal to the
width of the said ring c, as clearly illustrated in Figure 3. The opposite faces of
these two blocks are tapered divergently as clearly shewn in Figure 2, so that
if they were in contact they would enclose a triangular space. The wedge is about
half as thick as a block e in order that it may be moved across the tapered faces of
the blocks e, e. It is this wedge which is herein before referred to as the "one
member of the double wedge device."
9, 9 are two fixed abutments projecting radially from the inside face of the inner
piston ring c, and therefore facing the blocks e, e respectively. 9', glare guide
rods, each fast centrally to a block e and standing concentric with the ring c.
Both rods are sufficiently long to engage in holes 93, 9 in their respective

page_text: abutments. is a spiral spring surrounding each guide rod, and acting upon the
opposite faces of the said abutments and blocks, tending therefore to force them
apart and the blocks e, e together. Between the blocks e, e, there is interposed
what I have already referred to as "one member of the double wedge device."
This is a double wedge i. Those of its faces which are respectively opposite to
the tapered faces of the blocks e, e are tapered to the same angle and in the same
direction. It is illustrated in Figure 1 as extending from the piston ring e to the
internal ring so as to gain support from them both-see Figure 1. Inasmuch as
this wedge is charged with the duty of effecting the adjustment of the piston
rings by being moved over the tapered faces of the blocks e, e in the direction of
the taper thereof, it is only about half as thick as one of those blocks, as clearly
shewn in Figure 3.
The adjusting mechanism is illustrated in Figures 3 and 4 and is as follows. jis
a screw standing parallel with the axis of the pistou. It is supported in that
position by one end being introduced, preferably after having been rounded off or
shouldered, into a bearing formed in the inner face of one of the piston sides and
by the other end being passed through the opposite side. This other end has a
collar formed on it, and as this collar fits in a recess formed to receive it in the
inner face of the said opposite side of the piston, the screw is capable of motion
only about its axis. The said end of the screw projects for a short distance
beyond the piston where it is screwed to receive a locking nut and terminates in
a square is a portion of the cover of the cylinder in which the piston works.
A hole is bored through it axially coincident with the screw j, and a shouldered
nipple is screwed into the hole. The nipple is large enough to pass a box
spanner that will fit the locking nut as indicated in dotted lines in Figure 3. is a
box spanner adjusted to fit on the square for the purpose of turning the screw j.
m is a round plate loose upon the shank of the spanner behind the collar m'.
It is adapted to fit in and on the outer end of the nipple for the purpose of
steadying the spanner whilst it is being used. is a scale upon the face of the
nipple and is an index projecting from the collar m'. As the scale is one of
degrees of extension of the piston ring or one corresponding therewith, the position
of the index will indicate how much, under any given circumstances, the screw j
must be turned. The nipple is provided with a suitable closing device, e.g., a cap,
as indicated by dotted lines.
It must be understood that my invention is not restricted in respect of the
relative positions or respective numbers of any of the members of it described in
connection with the accompanying figures. Both numbers and positions may be
varied as also may the constructional details illustrated, provided the respective
functions specified retained.
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 I
claim is :-
1. The hereinbefore described combination of a double wedge device, a spring
compressible and extensible between a face of the said device and a face of an
abutment on the ring to be adjusted and mechanism for moving one member of
the double wedge device over the other of them, as set forth.
2. The combination of spanner, index and scale, as and for the purpose set
forth.
Dated thi. 02nd dow of Fahru 1804
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.