IMPROVEMENTS IN PIPE JOINTS OR COUPLINGS, APPLICABLE ALSO TO COUPLINGS PROVISIONAL SPECIFICATION
Year: 1870

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN PIPE JOINTS OR COUPLINGS, APPLICABLE ALSO TO COUPLINGS
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 8th September 1870.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PIPE JOINTS OR COUPLINGS, APPLICABLE ALSO
TO COUPLINGS FOR RODS AND SHAFTING," a communication from abroad by

page_text: William Clare Allison, of Philadelphia, Pennsylvania, United States
of America, to be as follows:-
This Invention consists of a coupling in which tapering and vanishing
screw threads on the ends of tubes, or pipes, and rods or shafting to be
coupled together or combined with a socket having internal vanishing
and tapering screw threads corresponding to those on the said tubes or
rods to be coupled, whereby a more perfect and secure junction is
obtained than has been heretofore accomplished by screw couplings.
In carrying out this Invention a tapering external screw is cut on
the ends of the pipes or rods to be joined, but instead of cutting the
thread of this screw to one uniform depth it is so cut that it shall
gradually vanish until it disappears at the exterior of the tube. The
socket instead of having a screw thread cut through it has two screw
threads tapering one in one direction for receiving the end of one tube
-or-rod, and-the-other-in-another direction for receiving the end of the
other tube or rod, the tapers of each screw corresponding with that of
the tube or rod which it has to receive, and the screw thread vanishes
to correspond with the vanishing thread of the tube or rod.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 8th March 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Eighth day of September, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
that I, the said John Henry Johnson, my executors, administrators,
and assigns, or such others as I, the said John Henry Johnson, my
executors, administrators, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the

page_text: A and A', Figure 2, represent on an enlarged scale sections of parts
of the ends of two adjoining wrought-iron tubes, such, for instance,
as are used in oil wells, B being the wrought-iron socket.
It has been usual to cut a slightly tapering screw on the ends of the
adjoining tubes, while an internal screw thread without any taper was
formed in the socket, hence but a portion of this internal thread of the
socket was in proper binding contact with the threads of the pipes, as
clearly shewn in Figure 2, the greater portion of the threads both on
the tubes and in the socket being of no avail as mediums for effecting
a tight junction of the two tubes. This defect will be understood on
reference to the diagram Figure 2, and therefore needs no further
explanation.
The slightest vibration or jar imparted to such a long tube composed
of lengths thus coupled together and suspended within an oil well, for
example, had a serious effect on these imperfect joints, and frequent
leakages occurred, and sometimes the tubes were torn apart and the
screw threads stripped.
There is another and perhaps greater objection than the above to this
mode of coupling tubes.
It was customary to cut the threads on the ends of the tubes to
a uniform depth throughout the threads, terminating abruptly in a
shoulder a, Figure 2, thus forming an incision at x, which was the
'nucleus of an easy fracture at that point, and such fractures frequently
occurred in oil well tubing, the socket B as it also terminates abruptly
at the shoulder a, affording no protection against such accidents.
Another objection arising from the abrupt shoulder a was that it
prevented the pipe from being screwed into the socket beyond the said
shoulder in order to tighten the pipe when it had become loosened.
In carrying out this Invention a tapering external screw is cut on the
ends of the pipes or rods to be joined, as shown at A", A, Figure 3,
but instead of cutting the thread of this screw to one uniform depth it
is so cut that it shall gradually vanish until it disappears at the exterior
of the tube, as shewn at y, Figure 3. It should be understood, however,
that the thread of the screw does not vanish so abruptly as is shewn in
that Figure, which is exaggerated and drawn on an enlarged scale in
order to shew the advantages of the Invention more clearly..

page_text: The socket B, Figure 3, instead of having a screw thread cut through
it, as in Figure 2, has two screw threads, tapering one in one direction
for receiving the end of one tube or rod and the other in another direction
for receiving the end of the other tube or rod, the tapers of each screw
corresponding with that of the tube or rod which it has to receive, and
the screw thread vanishes to correspond with the vanishing thread of
the tube, as clearly indicated in the Drawing.
The advantages of these improvements may be enumerated and
described as follows:-
First. There is a perfect metallic contact throughout between the
socket and the tube, every portion of the thread of one fitting the thread
of the other, hence a more perfect and secure joint is made than by the
old mode of coupling shewn in Figure 2.
Second. No abrupt shoulder, as at a, Figure 2, and no incision
forming a nucleus for a fracture of the tube, as at x, are presented
in this improvement, the vanishing screw preventing the formation of
such an incision.
Third. The socket adds to the strength of the tubes where the joint
occurs, whereas in the old mode the socket afforded no protection
against the fracture of the tube at x, Figure 2.
In this connection it may be observed that according to these improve-
ments the end of the tube may be screwed so far into the socket that
the end of the latter will project beyond the end of the vanishing and
tapering thread of the screw, as shewn at m, Figure 3, and this pro-
jecting end of the socket adds to the strength of the joint, which is in
fact more secure and more proof against tremors and jars than any other
part of the tubing.
The use of the tapering and vanishing thread also enables the pipe or
rod to be screwed into the socket until it becomes jammed tightly
O therein, which is another advantage possessed over the ordinary method
of coupling, the abrupt shoulder a in the latter preventing the joint from
being further tightened after the pipe or rod has been screwed into the
socket to that point.
It will be evident that although the Invention is represented as
5 applied to pipes or tubes only it might be applied with advantage to the

page_text: coupling of rods, such as are used in bridges, for instance, or to the
coupling of shafting.
Having now described and particularly ascertained the nature of
the said Invention, and the manner in which the same is or may be
used or carried into effect, I would observe in conclusion, that what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent is, the
rods or tubes A, A', having tapering ends and tapering threads upon the
same, in combination with a sleeve having tapering sockets and threads
corresponding to those on the pipes, tubes, or rods, as set forth and
illustrated by the Drawing.
In witness whereof, I, the said John Henry Johnson, have to this.
my Specification set my hand and seal, this Seventh day of
March One thousand eight hundred and seventy-one.