IMPROVEMENTS IN PACKINGS FOR PISTON RODS
Year: 1879

page_text: LETTERS PATENT to James Willard Preston, of the City of Boston, County of
Suffolk, and State of Massachusetts, United States of America, for tho Inven-
tion of "IMPROVEMENTS IN PACKINGS FOR PISTON RODS." A communication
by Thomas Tripp, of Boston, County of Suffolk, and State of Massachusetts,
United States of America.
Sealed the 25th April 1879, and dated the 24th February 1879.
COMPLETE SPECIFICATION filed by the said James Willard Preston at the
Office of the Commissioners of Patents on the 24th February 1879.
JAMES WILLARD PRESTON, of the City of Boston, County of Suffolk, and State
of Massachusetts, United States of America. "IMPROVEMENTS IN PACKINGS FOR
PISTON RODS." A communication by Thomas Tripp, of Boston, County of Suffolk,
and State of Massachusetts, United States of America.
This Invention relates to improvements in packings for piston rods, etc., whereby
such packing accommodates itself to the movement of the rod and retains at all
times a perfect bearing and a position at right angles to the axis of the latter,
thus avoiding the strains and thrusts and leakage of steam incident to many piston
rod packings in use; and my Invention consists in a construction and arrangement
of parts as herein-after described.
The Drawings accompanying this Specification represent in Figure 1 a sectional
elevation of a packing containing my Invention; Figure 2 is a face view of the
sectional packing plates or rings; Figure 3 is a face view of the annular or washer
to be described; while Figures 4 & 5 are sectional views of the said rings. In the
above-named Drawings I have represented at A what may be considered part of
the piston rod of a steam cylinder, the front portion or flange of the cylinder head
through which such rod passes being shown at B.
In carrying my improvement into effect I provide an annular plate or flange C,
which I bolt flatwise to the portion B of the cylinder head, the said plate C
constituting in effect the base or supporting plate of my packing and loosely
surrounding the piston rod, in order that the latter may be permitted slight side
play within such plate.
The packing element or feature in this case consists of two hook shaped collars
or sectional rings D, D, which enclose the rod A outside of the plate C, the united
outer peripheries of these collars being preferably circular and the coinciding or
meeting faces being straight and parallel in order that one may slide upon the
other as they are crowded inward to take up wear upon their inner peripheries,
Price 6d1

page_text: while the conjoint inner peripheries of the sectional rings constitute a cylindrical
bore to encircle tightly the rod A.
To prevent tendency to separation of the semi-rings endwise of the rod A. I
connect the two by dowels and mortise a, b, while to break the joints between the
semi-rings D, D, upon the inside I employ an annular circular washer or packing
plate E, which surrounds the rod A and is interposed between the plate C and said
rings.
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1
The intermediate plate E also serves to confine the semi-rings D, D, in their
proper place transversely of the rod A, and in order to permit of endwise move-
ment of such rings upon one another, as their inner faces become worn by friction
upon the rod, I connect them with the plate E. by dowel pius or spurs c, c, etc.,
which play in slots d, d, etc., created in said plate, as shown in Figures 2 & 3 of
the Drawings.
To temporarily seal the joint between the faces of the rings D, D, and the
periphery of the rod A until such rings find a smooth and true bearing upon such
rod I employ a ring e of india-rubber or other elastic material, which is let into a
common channel fformed in the conjoint inner peripheries of such rings; as the
rings become fitted to the rod this packing ring e may be removed or allowed to
remain as may be preferred.
To confine the semi-rings D, D, in place upon the rod A. I employ an annular
head or follower F which encircles the rod A, and is confined to the plate. C by
bolts g, g, etc., while to crowd the said rings closely up to and so as to tightly
enclose the said rod I form upon the inner face of such head F two sloping ears
or inclined planes n, n, which operate with corresponding inclined or oblique faces i
formed upon the peripheries of the said rings D, D, as shown in Figure 1 of the
Drawings.
It will be evident that by crowding the head F inward by means of the bolts g
its inclined ears n will wipe against the adjacent sloping face i of the rings D and
crowd the latter inward upon opposite sides of the rod A, so as to tightly hug the
latter and prevent escape of steam, while at the same time the intermediate packing
ring E is tightly crowded up to its seat upon the plate C.
As before stated the dowel pins a are for the purpose of preventing end play of
the rings D upon the rod, and with small piston rods they serve the purpose; but
with large piston rods in which the rings are of considerable size I prefer to employ
guage screws k, which are screwed through the outer head or cap F and abut
against the outer sides of the rings. Should the inner periphery of the rings D in
time become worn so as to permit of leakage of steam between them and the
collar E or the plate C or between them and the rod A by reason of a general
slackness of the parts, the screws are to be retracted to a slight extent and the
nuts of the bolts g screwed upon the head F to a corresponding degree, which
effectually tightens the joints between the various parts.
It will be seen that I am enabled to dispense with the springs now generally
employed in packings of this character to maintain the parts generally in place
about the piston rod.
It will also be seen that any swaying or irregular movements of the rod with
respect to the axis of the cylinder do not loosen or start the various joints of the
packing, as the entire device moves with the piston rod and slides upon the plate C
or the piston head and thus accommodates itself to the movements of the rod, as
the bolts g will swing sufficiently to prevent of this without throwing the various
parts out of a position at right angles to the axis of the rod.
The entire packing device is outside of the cylinder head and readily accessible.
It is simple, effective, and durable, and furthermore not liable to derangement and
wear. A modification of my Invention would be to dispenso with the packing
plate E, and in its place employ a second pair of sectional rings which are duplicates
of the rings D, D, and are placed alongside of the latter, as shown in elevation in
Figure 6 of the Drawings, and in such manner that the rings of one pair break the
joints of the opposite pair. In this latter arrangement the two pairs of rings are

page_text: permitted to play upon one another toward the piston rod in one direction but not
in the opposite direction, and their movements are controlled by dowel pius and
slots, arranged similarly to those shown in Figures 2 and 3 of the Drawings.
CLAIMS.
First. A rod packing composed of the semi-rings D, D, plate E, and head N with
its oblique ears n, n, the said parts being connected with the cylinder head by the
plate C and bolt g, and the whole operating substantially as herein described.
Second. The packing plate E disposed intermediate between the semi-rings D, D,
on the one side and the cylinder head or the plate Û on the other, and serving to
break the joints between the said rings and to confine them together upon the rod
transversely of the latter, substantially as herein described.
Third. The elastic ring or strip e in combination with the rings D and rod A.
Fourth. The head F with its sloping cars n operating with inclined face upon
the semi-rings D, D.
Fifth. The peculiar shape of the semi-rings D, D, as shown in Figure 2 of the
Drawings, that is to say, with semi-circular bore to clasp opposite sides of the rod
and with straight parallel faces to meet and slide upon each other to compensate for
wear.
Sixth. The semi-rings D, D, and plate E as connected by the pins and slots c, d,
or equivalent means for permitting of endwise movement of said rings one upon the
other transversely of the rod.
Seventh. In general combination the plates D, D, and E, cap F, with its ears n, n,
and base plate C or its substitute, the whole operating with the piston rod and
cylinder head essentially as and for purposes stated.
Eighth. The semi-rings D, D, enveloping the rod, substantially as stated.
Ninth. The two pairs of rings as shown in Figure 6 of the Drawings, enclosing
the rod and breaking joints one with the other, substantially as stated..
In witness whereof, I, the said James Willard Preston, have hereunto set my
band and seal, this 26th day of December 1878.
TAMES WET ADD DD DOL
.

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