Improvements in Metallic Packing for Piston Rods and the like.
Year: 1894

page_text: COMPLETE SPECIFICATION.
Improvements in Metallic Packing for Piston Rods and the like.
I, CHARLES FRANCIS CHURCHILL, of Melrose, in the County of Middlesex
and State of Massachusetts, United States of America, 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 that class of piston-rod or valve-stem packings in which
are employed segmental or divided metallic packing rings enclosing the rod or
stem and adapted to be forced by the steam pressure firmly together about the rod
or stem to make a steam tight joint therewith. By my improvements the rings
and other parts which bear upon and serve to compress the segments of the packing
around the rod are also laterally separable so that they may be applied around the
rod or stem in an existing engine without disconnecting the cross-head.
My invention consists in the novel construction and combination of parts
hereinafter described and illustrated in the accompanying drawing in which
Figure 1 is a longitudinal section through a stuffing box provided with my
improved packing, the piston-rod and the bolts which secure the gland in place
being shown in elevation.
Figure 2 is a perspective view of the interior segmental packing or sleeve,
showing the three segments connected as when in use and the axial recess through
which the rod or stem reciprocates.
Figure 3 is a longitudinal section through said segments, showing the bearing
surface for the rod crossed by transverse grooves to hold the lubricant.
Figure 4 is an end elevation of the sleeve or inner packing made up of said
connected segments.
Figure 5 is an end view of one of the exterior rings which surround and compress
the segments, this view showing the ring made in two parts dovetailed together so
as to be separable, and
Figure 6 is a side view of another severed ring, which in use, is interposed
between the gland and the packing, its tapered outer walls entering the mouth of
the stuffing box.
A represents a portion of the cylinder-head or cover upon which is formed the
stuffing box B through which the piston rod C reciprocates. The outer end of
said box has the usual gland or cap D secured in place by the bolts E E.
F represents a sleeve or composite body of packing divided radially on longi-
tudinal lines f, Figures 2, 3 and 4, into three equal segments having concave inner
surfaces to bear upon the rod C. This segmental sleeve tapers externally from its
central portion toward each end, each half thus being substantially frusto-conical,
as is well shown in the drawing.
G and H are exterior packing rings which surround the tapering ends of the
composite sleeve F, and fit snugly thereon, being internally tapered to correspond
exactly therewith to press the segments closely together.
These rings are made in halves so that they may be applied laterally to the
piston-rod C and around the segmental sleeve F without disconnecting the cross-
head; and these halves are dovetailed or hooked at their ends as at and h, so as
to engage with each other by an axial sliding movement to make up a complete
ring. This feature is well shown in Figure 5, where the parts are seen interlocked
and in the position for use, while Figure 1 represents them thus engaged and in
section on the line x, x of Figure 5. This sliding movement along the piston rod
enables the parts of each ring to be connected and disconnected at will when

page_text: the stuffing box is open, and thus permits the rings to be readily applied and
removed. They, however, bear upon the tapering ends of the sleeve F and
press its segments into close contact with each other and with the piston rod C.
The parts of the rings G and H may, if preferred, be detachably connected by
screws or any equivalent mechanical device.
Between the gland D and the packing ring H, 1 interpose another two-part
ring J, shown in Figures 1 and 6 externally tapering so as to enter the mouth
of the stuffing box B and bear against the inner walls thereof. This surface
contact tends to bring the parts of the ring closely together and to force them
toward the reciprocating piston-rod C. They therefore need no hooks or other
fastenings to unite their ends.
To prevent the passage of steam along the division line between the segments
of the composite sleeve F, I provide a series of metallic keys K, preferably of
brass and rectangular in form, which said keys are inserted in slots of like shape
formed in the adjacent edges of the segments, across the joints or division lines f.
These keys thus extend radially through the sleeve F from its inner to its outer
surface, as seen in Figure 1, their outer ends being shown in Figures 2 and 4 and
their inner ends in Figure 3, crossing the joints f. They therefore serve the
double purpose of intercepting the steam and keying the segments together,
preventing longitudinal displacement.
I prefer to form annular grooves L on the inner surface of the composite
sleeve F, see Figures 1, 2 and 3. These grooves are parallel to each other and
may be formed in the inner ends of the keys K, Figure 1, as well as in the
body of the segments of the sleeve. They serve as receptacles for surplus
material and the matter set free by attrition.
When the engine is in operation the steam which escapes into the stuffing box
presses the ring G toward the ring H, compressing the parts of the sleeve F
between them, and causing them to grip the rod G closely and make a steam-tight
joint. When the steam pressure is reduced or stopped, the tension upon the
packing relaxes proportionately and the rod passes freely through the stuffing box
with little friction. The construction described effects the important double result
of a steam tight joint when the work to be done requires it and reduces friction and
wear of parts at other times.
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 :-
The hereindescribed packing for stuffing boxes, consisting of the inner segmental
sleeve F separated by radial planes and tapering externally from its middle
portion toward each end, the radial keys K crossing said planes and closing the
joints between adjacent segments, in combination with the compressing rings G
and H internally tapered to conform to said sleeve, each made in two engaging
parts so as to be applied around the piston-rod laterally and connected for use, and
with the tapered two-part ring J, interposed in the mouth of the stuffing box
between the gland D and the ring H, substantially as set forth.
Dated this 10th day of August 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.