Improvements in Screw-couplings for Pipes and other Screw Joints.
Year: 1892

page_text: Date of Application, 6th May, 1892-Accepted, 2nd July, 1892
COMPLETE SPECIFICATION.
Improvements in Screw-couplings for Pipes and other Screw Joints.
We, CORNELIUS ALFRED FOLLY, Engineer, of 90 Hill Street, West Hoboken,
LIVINGSTON
County of Hudson, and State of New Jersey, WILLIAM
FLANAGAN, Brewer, of 6 West 43rd Street, New York, County and State of New
York, and DE WITT CLINTON WARD, Merchant, of 137 East 94th Street, New
York, County and State of New York, United States of America, 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 and accompanying drawings :—
The present invention relates to improvements in screw-couplings and other screw
joints, and its object is to render such couplings of pipes and other screw joints
liquid and gas tight.
The invention consists in the combination, with the internally screw-threaded
part of a screw-coupling having a circumferential groove cut in the threaded part
for receiving a packing-ring of lead or analogous material, of an internally
screw-threaded packing-ring inserted in the groove and made of smaller diameter
than the internally threaded portion of the coupling.
It also consists in an internally-threaded coupling having a lateral hole
communicating with the circumferential groove and containing a lead arm formed
integrally with the packing-ring or a screw inserted in the coupling and bearing
upon the packing-ring for the purpose of taking advantage of the well-known
property of the flow of metals for tightening the joint, either by forcing the metal
in the lateral hole by means of a punch or by forcing the screw placed in the hole
into the packing-ring, thus causing the metal of the ring to flow around and closely
fill the circumferential groove, and at the same time also to form an intimate
contact with the externally threaded portion of the coupling.
The invention is illustrated in the accompanying drawings constituting a part
of this Specification, in which―
Figure 1 is a longitudinal section of a pipe-elbow, showing one end thereof
prepared for the application of my improvement, while the other end illustrates the
manner of applying my improvement; and
Figure 2 is a side elevation, partly in section, of a pipe-elbow provided with my
improvement, similar letters of reference indicating corresponding parts in both
views.
In the drawings the elbow A is provided with an internally threaded portion B,
in which at or near the center thereof is formed an internally circumferential
groove C, which cuts away a portion of the threads. In the side of the elbow is
formed a hole D, which communicates with the circumferential groove C.
To form the packing-ring in the groove C, it is preferred to use an externally
threaded mandrel E, smaller in diameter than the internal diameter of the screw.
portion of the elbow, which is inserted in the threaded portion, as shown, and lead
or analogous material is melted and poured through the lateral hole D into the
annular space surrounding the mandrel E. When the mandrel E is removed from
the threaded portion of the elbow, an internally threaded soft-metal packing-ring F
is left in the groove C, and, owing to the reduced diameter of the mandrel E, the
packing-ring F is of smaller internal diameter than the threaded portion of the
elbow. With this construction when the tapered end of the pipe is screwed into
the elbow it enters the packing-ring F and expands the same, so as to thoroughly
fill the groove C and the threads of the pipe screwed into the elbow. After the
pipe has been screwed home and the fit is made as tight as possible by this means,
if it becomes necessary to secure a still greater compression of the soft-metal
packing-ring F, this may be done by inserting a punch in the_hole D and forcing

page_text: the metal contained therein into the annular space around the pipe. In lieu of a
punch, the hole D may be internally threaded and a screw G may be inserted
therein, and the compression of the soft metal may be effected by turning the
set-screw so as to force it into the metal and cause the metal to flow in the annular
space around the pipe. After the joint is made up and applied where steam or hot
liquids pass through it, the lead of the packing expands back to its normal state by
becoming heated and makes an absolute tight joint, it being understood, of course,
that the lead has been compressed when cold.
It will be seen that the soft-metal ring is cast in an internally threaded female
member and is of a diameter less than the bore of such threaded member, and that
it is then compressed outwardly or expanded by the male member, which not only
results in a tightly compressed ring, but relieves the same of the strain of expansion
and contraction, the strain being sustained by the internal threads of the female
member and not by the soft ring. In the above construction, also, the pressure
applied through the radial opening is additional to and co-acts with the outward
pressure of the male member of the coupling.
The invention has been shown in the accompanying drawings and has been above
described as applied to a pipe-elbow but it may be applied with equal facility to
any screw-joint where a tight fit is required, and is especially advantageous where
gases and vapors under high pressures are used.
It is known that a metal packing having shallow threads formed in it has been
arranged in an annular groove of a coupling-socket whose internal surface is not
threaded, the packing being of less internal diameter than that of the socket, so
that when the pipe is screwed into the socket it cuts the thread deeper and is held
in the socket solely by its engagement with the packing; and it is also known that
an internally threaded socket has been provided with an annular groove, in which
is placed a feather or other similar packing, such packing being of less internal
diameter than the diameter of the socket, so that the packing will be firmly
pressed into its groove when the pipe-section is screwed into the socket, and
therefore neither of these constructions is claimed herein.
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 :-
1. In a coupling or screw joint, the combination, with an internally screw-
threaded female member having an annular groove in its threaded portion, with a
portion of the threaded surface on each side of the groove, of a metal packing cast
in said groove and having an internal diameter less than the diameter of the said
female member, substantially as described.
2. In a coupling or screw-joint, the combination, with an internally threaded
female member having an annular groove in its threaded portion, of a metallic
packing cast in said groove and having an internally-threaded surface of less
diameter than the diameter of the threaded surface of the female member, whereby
when a pipe is screwed into the said female member the packing will be
expanded and made to thoroughly fill the groove and the threads of the said pipe,
substantially as described.
3. In a coupling or screw-joint, the combination, with an internally threaded
female meinber having an annular groove and a threaded opening leading from the
outside to the said groove, of a soft-metal ring internally screw-threaded and fitted
in the said groove, the said ring being of less internal diameter than the diameter
of the said internally threaded female member, and a screw-threaded plug for
closing the said opening and compressing the soft-metal ring into the groove,
substantially as and for the purpose set forth.
Dated this 4th day of Mar 1902
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.