Improvements in Metallic Packing Mechanism for Piston Rods and for similar Purposes.
Year: 1893

page_text: Date of Application, 4th Aug., 1893-Accepted, 9th Sept., 1893
COMPLETE SPECIFICATION (AMENDED).
Improvements in Metallic Packing Mechanism for Piston Rods and
for similar Purposes.
We, WILLDRED Eldred Plummer, of 35, Whetley Lane, Bradford, in the County
of York, Manager of Works, and WILLIAM MARSDEN KERMODE, of 27, White's View,
Bradford aforesaid, Secretary, 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 improvements in the construction and arrangement of
metallic packing mechanism for piston or other reciprocating rods and for like
purposes. The general design of the packing is well known and includes a ball joint
kept in position by follower springs, with blocks held in a ring and pressed onto the
rod by springs. In another form of this packing, babbit rings held in a conical cup
and kept in position by follower spring take the place of the blocks.
In packings of this class when applied to steam engines the object aimed at is to
allow perfect freedom to the piston rod in its lateral movements, and still to keep the
passage from cylinder perfectly steam-tight. If the lateral motion is considerable,
allowance has to be made in the construction of the packing, that the rod may not
come in contact with any fixed part, and the provision of this clearance has hitherto
been difficult without reducing the value of the packing by shortening the period
during which a set of the packing blocks will last. This will be better understood by
reference to Figures 1 and 2 of the accompanying sheet of drawings. Figure 1 is a
section through the packing showing longitudinal view of the piston rod, and
Figure 2 shows a cross section of the packing and piston rod. Similar letters refer to
the same parts on all the views.
L
In Figures 1 and 2 the packing case D is bolted to the cylinder cover and encloses
the ball joint E, sliding plates A and B, packing blocks F, FI held in the horn rings
G, G, which have pockets holding springs H keeping the said packing blocks in close
contact with the piston rod C. The follower spring holder K is covered by a plate J
which may be made with or without a flange but in any case will not be able to move
laterally though able to rock freely. It will be seen that all the packing is done by
the blocks F, F1, and as these are constantly wearing out the larger they are in.
outside diameter, the longer they will last, for they can only wear until their outer
edge coincides nearly with the inside diameter of the ball joint E, supposing the
plate A was not there. Therefore the larger the ball joint be bored to allow for
clearance, the shorter the time the blocks will last.
By introducing the plates A and B it will be seen that any required amount of

page_text: clearance can be allowed without materially reducing the life of the packings and in
addition wear on the packing blocks will be obviated except on the surface that is in
contact with the rod, and this will be found to constitute a material advantage as
the finished surfaces are not liable to become worn and allow the steam to pass.
Between the back sliding plate B and the follower springs we introduce a small
plate J, flanged or plain, but arranged so that it cannot move laterally though it can
rock. This is to overcome the trouble that would be caused if the plate B moved
to and fro over the ends of the small springs, wearing them and having a tendency to
break them off. The plate J will move to accomodate itself to any rocking motion
that may be set up in the packing, without rubbing against the follower springs.
Figure 3 is a section through a modification of this form of packing, embodying
the principle of the ball and socket ring, with the follower spring or springs at the
back, but with babbit or other metal rings M fitting in the cone cup L. The
follower N serves to transmit the pressure of the follower springs keeping the rings
and cup in position. We here employ a plate J to rest against the springs, so that it
can rock without moving laterally, and hence the follower N which may be made with
or without a flange can slide against it. When the packing is for a rotating rod we
may make the flange of N with a groove so as to reduce the frictional surface bearing
on J and we may also make the spring holder K so that it fits the rod, being lined
with some soft metal in which grooves are turned as shewn. This arrangement will
adit of the cap L with rings M and follower N rotating freely with the rod and not
catching on the springs.
Figure 4 shows a modification of this packing in which the two forms previously
described are combined. This may be done in the ease of exceptionally high pressures
or other special circumstances and forms practically a double packing. It may be
used with or without the ball joint El, and the spring holder may be made as shewn
at
with one end pressing against the follower N or it may be arranged so that the
springs press against a plate J in contact with the follower N as shewn in Figure 3.
Where the packing is out of the bottom of the cylinder we may use a neck bush P
which enters the bottom of the cylinder as far as the piston will allow, so as to serve
as a trap for any débris that may be in the cylinder, and prevent same passing into
the packing.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what we
claim is
4. In-self-adjusting-metallic packing mechanism, the combination with the
ease, bull joint, blocks, horn--rings, springs and spring holder, of the -sfiling
plutes-Al-and-spring-covering-plated, substantially-us-and-for-the-purpose
described herein.
2. In-n-self-adjusting metallic meking-mechanism, the combiuntion-with-the
ease, ball joint, cone-cap-and-metal-rings of the grooved spring holder K, spring
covering-plate-J.-and-follower-N grooted--or-plain, substantially as shewn-und
described herein.
3- In a metallic packing mechanism the combination with the case. ball ioint.
ense, ball joint, blocks, horn--rings, springs, and spring holder, of the sliding
plates-And-spring-covering plute de substantially-us-und-for-the purpose
described herein.
2. In-n-self-adjusting metallic meking mechanism, the combiuntion-with-the
ease, ball joint, cone-ep-and-metal-rings, of the grooved spring hobler K, spring
covering plute-nd follower N-grooved--or--plain, substantially as shown and
described herein.
3 In a metallic packing mechanism the combination with the case. hall ioint.
sliding plates, blocks, horn rings, springs, spring covering plate, and spring holder,
of the cone packing, consisting of conical cup, metal rings, follower and spring holder,
with or without the ball joint, covering plate to springs, or trap bush, substantially
as shewn and described herein.
1000
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicants.