Year: 1888

page_text: Date of Application, 2nd July, 1888
Specification Accepted, 28th Sept., 1888
I, HERBERT JOHN ALLISON, of the firm of Allison Brothers, of 52 Chancery Lane,
London, in the County of Middlesex, Patent Agents, do hereby declare the nature
of this invention which has been communicated to me from abroad by William
Edward Crist, and Thomas Hawkins, both of the City of Brooklyn, in the County of
Kings and State of New York, United States of America, Machinists, 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 the combination of metallic packing-plates with the ends
of the piston in a vibrating-engine to make a close joint between the piston and the
walls of the chamber in which it works, and has for its object to make a durable, self-
adjusting, elastic joint which will remain perfectly steam-tight under long continued
wear and pressure.
It consists in the combination with the end and side edges of the piston of
jointed and pivoted packing strips having the form and arrangement hereinafter
fully described, and which are inserted, as set forth, in longitudinal recesses in
said edges.
In the accompanying drawings:
Figure 1, is a sectional view through one end of the piston-chamber of a
vibrating-engine, showing the proximate end of the piston and its packing in
elevation.
Figure 2, is a central section through the piston in line x-x of Figure 1, showing
the packing partly expanded in all directions by reason of wear.
Figure 3, a transverse section through a portion of one end of the piston and its
packing, in line y-y of Figure 2, and
Figure 4, a transverse section across the same end in line 2- of Figure 1; both
.
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page_text: views showing the packing expanded by wear, the wall of the piston-chamber being
omitted in said views.
A, A, represents the piston-chambers and B, the vibrating piston of a compound
vibrating-engine of the type described in Her Majesty's Latters l'atent No. 5228 issued
April 28th 1885.
The edge of the piston, at its ends and sides, is centrally and longitudinally recossed,
as shown at in Figure 3, to receive the improved packing-strips.
These strips D,D), and E, E, are made severally of a length, width and
thickness to fit closely and accurately within the roves in the edges of the
piston. The strips D, D, at the sides of the piston are jointed to the strips E, E,
at its ends, by a simple, halved joint and are pivoted together by a transverse
pivot pin f
Each strip E is dividel centrally by a lap-joint as shown at in Figure 4, and
the joint thus formed is broken' and covered on the face thereof adjacent to the
piston, by means of a thin, underlying plate H, rivetted at one end to one division
of the end strip E to oxtend under and overlap the other division, so far as the joint
extends.
The joints of the ends of the lateral strips D with the trunnions I, I, of the piston,
are severally covered and kept tight when the packing is drawn away from the trunnion,
by means of metallic rings K, K, encircling each trunnion' and fitting into a recess
cut in the inner face of the lateral strip at its inner end to receive it, each ring being
however lapped on its inner side by a thin spring-plate L, rivetted to the strip to move
with it, as shown in Figure 2.
The tendency of the free end of the elastic-plate L is to spring outwardly, so that,
as the ring K against which it bears, wears away, the pressure of said plate L against
it will operate to keep the joint tight.
The several packing strips are automatically forced outward from the piston and
kept in constant contact with the walls of the piston-chamber by means of spiral-
springs S, S, S, interposed between the strips and piston and fitted into recesses
formed for the purpose in the piston as shown in Figures 2 and 3. Similar springs
may, in the larger sizes of engines, likewise be inserted between the ring K and its
sent in the piston, as shown by dotted lines in Figure 1, either in addition to the
olastic plates L or as a substitute therefor.
The lateral strips D, I), may likewise in the larger engines be divided in their length
with a lap-joint corresponding to the lap-joint G of the end-strip E and provided in
like manner with an underlying plate H.
In the operation of this improved packing, as the packing strips become worn by
reason of their friction with the walls of the piston-chamber, the central joints G, G,
in the end-strips E, and the end-joints of the lateral strips with the rings K, K, permit
a movement of all tho strips both outwardly and longitudinally, so that they may be
held by the spiral springs S, S, in contact with the internal faces of the chamber
throughout the entire movement of the piston and in spite of the constant wear theroof
by reason of said movement.
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 combination in a packing for vibrating-pistons, of divided ond strips fitted
in a longitudinal recess in each end of the piston, lateral strips fitted in longitudinal
recesses in the side edges of the piston and jointed and pivoted to the end-strips at
the corners of the piston, packing-rings seated in the piston to encircle its trunnions
and embraced within recesses at the inner ends of the inner sides of the lateral packing
strips, plates made fast to the side-strips to cover the inner face of each packing
ring, a plate fast to the inner face of ono division of each end-strip to cover its
joint with the proximate division, and a series of springs interposed between the
several packing-strips and the piston, substantially in the manner and for the purpose
heroin set forth.

page_text: 2. The combination in a packing for vibrating pistons having solf-adjusting
end-strips substantially as described, of lateral strips fitted each in a longitudinal
recess in the side edge of the piston, packing-rings seated in the piston to encircle its
trunnions and which are severally embraced within recesses at the inner ends of the
inner sides of the lateral packing-strips, and spring devices, substantially as described,
for forcing the rings and strips outwardly against the wall of the piston-chamber,
substantially in the manner and for the purpose herein set forth.