Improvements in Piston Packing for Steam Engines and for other Purposes.
Year: 1890

page_text: Date of Application, 1st Apr., 1890-Accepted, 3rd May, 1890
COMPLETE SPECIFICATION.
Improvements in Piston Packing for Steam Engines and for other
Purposes.
A communication from FRANKLIN DAVID CHILD, of West Newton, in the County of
Middlesex, and State of Massachusetts, United States of America, Mechanical
Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 relates to piston packing for steam engines and other purposes and
it consists in certain novel features of construction, arrangement and combination of
parts which will be readily understood by reference to the description of the
drawings.
Figure 1 of the drawings is a sectional elevation of the piston head and packing
rings with the follower removed the cutting plane being on line 2 2 on figure 2.
Fig. 2 is a section on line 3 3 on figure 1.
Fig. 3 is an exterior elevation of the expansible packing ring with the locking
device in position to bridge the joint of said ring.
Fig. 4 is a similar elevation of the same ring with the locking device removed.
Figs. 5, 6 and 7 are respectively a plan, an end view and a sectional elevation of the
locking device the cutting plane of said section being on line 4 4 on figure 5.
Fig. 8 is a partial section of the outer and inner rings illustrating a modified form
of applying the locking device the cutting plane being on line 5 5 on fig. 9.
Fig. 9 is a partial exterior elevation of the outer or expansible ring shown in fig. 8
with the locking device in position.
Fig. 10 is a similar elevation of said ring with the locking bar removed.
Fig. 11 is an exterior elevation of a portion of the inner ring.
Fig. 12 is an elevation of the inner face of the locking bar shown in figure 8 and
Fig. 13 is a side elevation of the same.
In the drawings A is the piston head provided with the central hub A¹ and the
radiating ribs A' to which the follower B is bolted in a well known manner.
C is an inner endless ring having formed in its periphery the rectangular slot or
groove a and clamped firmly in a fixed position between the follower B and the flange
of the piston head A by the bolts a' a' which secure the follower in. position.
"D is the packing ring proper cut open at 6 and having formed on each edge
thereof upon each side of said line of separation the oblique grooves c and e¹ the
grooves being inclined in opposite directions relative to the outer and inner surfaces of
said ring the two side walls of each groove being parallel with each other as shown.in
figures 1 and 7.
.
Those portions of the ring D between the line of separation and the oblique
groove c and c¹ are made somewhat narrower than the main body of said ring as
shown in figure 4.
E is the locking device made in two parts each composed of a side plate d and
two inwardly projecting oblique lips or ribs e e adapted to fit the oblique grooves c c¹
in the ring D and the inwardly projecting flange said flanges on the two halves of
said locking device abutting against each other when in position to lock the severed
ends of the ring D and may be secured together by the rivets g g or left disconnected
as may be preferred as they cannot become displaced when once in position in the
piston.
The usual way of making and fitting packing rings for steam pistons is to turn
the ring to the desired width and thickness and to a diameter say one fourth of an

page_text: inch more or less greater than the interior diameter of the cylinder in which it is
to be used, cut out a piece of sufficient length circumferentially to prevent it to
be sprung together so as to reduce its diameter to the diameter of the cylinder in
which it is to work.
The spring of the ring itself and the tension of the spring which are sometimes
placed inside of the ring so as to bear thereon tend to press the ring into close contact
with the inner surface of the cylinder.
The space between the packing ring and the body of the piston or the inner ring C
is usually filled with steam which also acts to press the packing ring outward. This
pressure of steam is often so great as to cause an unnecessary wear of the packing
ring and also of the cylinder thereby necessitating the renewal of the packing ring in
a much shorter time than is desirable.
To obviate this difficulty is the object of the present invention and to this end after
turning the ring and cutting it apart precisely as above described the inclined grooves
are formed in each edge of the ring on each side of the line of separation or in
other words the ends of the ring near said line of separation are formed as shown
in figs. 1, 3 and 4, and a locking device E formed as shown in figs. 5, 6 and 7, is
applied thereto with its inner portion projecting into the recess slot a of the inner.
ring and a light leaf spring his placed between said inner ring and the locking
device E as shown in fig. 1.
The two ends of the cut packing ring when sprung into position to fit the cylinder
in which it is to operate are locked together by the locking bar E which when
inserted in the cylinder prevents the packing ring being expanded to an injurious
extent by the reaction of its own elasticity or the pressure of the steam which may
find its way between the two rings for the reason that the contact of the inclined
shoulder on the ring next to the line of separation of said ring with the inner
inclined shoulders on the locking device prevents any farther expansion until the
outer or curved surface of the locking bar wears away so as to be forced farther away
from the centre of the piston by the spring h or the pressure of steam. between it and
the body of the piston or the inner ring.
Instead of cutting the inclined grooves c c and forming the locking bar as shown
in figs. 5, 6 and 7 a T shaped slot ; may be formed in the centre of the width of
the ring at each side of the line of separation as shown in fig. 10 the inner ends of
said slots being made parallel to the end surfaces formed by cutting said ring apart
as shown in fig. 8 or said inner ends of said slots may be made radial to the axis of
the piston as may be preferred, and the locking bar may be made as shown in.
figs. 12 and 13 and applied to the slots ; as shown in figs. 8 and 9 and a good
result will be attained although the form shown in figs. 1 to 7 inclusive is preferred.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-.
1. A cut packing ring provided with shoulders on each side of its joint inclined
to the inner and outer surfaces of said ring with their outer ends nearest to said
joint, and a device for bridging or breaking said joint and provided with corre-
sponding inclined shoulders to engage the shoulders on ring and lock the two ends
of the ring together and control the degree of expansion thereof.
2. A cut packing ring having formed in each edge thereof and upon each side of
the line of separation a slot or groove the two side walls of which are parallel to each
other and oblique to outer and inner surfaces-of-said ring with their outer ends
nearest to the line of separation of said ring the slots or grooves upon opposite
sides of said line of separation being inclined in opposite directions: in combination
with a locking device having inwardly inclined lips to fit the grooves in said
ring and lock the ends of said ring together and bridge the space between the ends
of. said.ring.
3. In combination with a cut packing ring having shoulders formed in each edge
thereof and on each side of the line of separation of said ring said shoulders being

page_text: inclined to the outer and inner faces of said ring with their outer ends nearest to the
line of separation, a locking bar or device made in two parts each provided with two
correspondingly inclined shoulders to engage with said shoulders on the ring and
bridge the space between the ends of the ring.
4. The combination with a piston head and follower of the out ring D provided
with the slots or grooves c c inclined in opposite directions with their outer ends
nearest to the line of separation of said ring, the locking device E provided with
the lipse e inclined in opposite directions and arranged to fit the grooves e o and
lock the two ends of the ring together and control the degree of expansion thereof
and the endless ring Chaving formed therein a rectangular slot to receive the
inner connecting plate of the locking device.
5. The combination with a piston head and its follower of the cut ring D, the
endless ring C, the lock E, and the spring hall constructed arranged and operating
substantially as described for the purposes described.
Thated this 1nd devel A:1 1000
W. P. THOMPSON & BOULT,
Agents for the Applicant.