Improvements in or connected with the Joints of Thin Metallic Pipes or Tubes and in Apparatus for use in the Manufacture thereof.
Year: 1891

page_text: Date of Application, 9th Feb., 1891
Complete Specification Left, 7th Nov., 1891-Accepted, 12th Dec., 1891
PROVISIONAL SPECIFICATION.
Improvements in or connected with the Joints of Thin Metallic
Pipes or Tubes and in Apparatus for use in the Manufacture
thereof.
I, JOHN MORRIS NEWTON, of Clarence Street, Stalybridge, in the County of
Chester, Mechanical Engineer, do hereby declare the nature of this invention to be
as follows:-
This invention relates to thin pipes or tubes of ductile metal for conveying
water, steam or gas which are not thick enough or have insufficient substance in
which to cut or chase a screw thread and is designed with the object of forming on
the ends of such pipes or tubes a joint or coupling whereby two lengths may be
securely and effectively connected together.
It consists essentially in forming a corrugated or indented screw thread (not cut
or chased) upon the ends of such pipes with a coupling similarly formed and in
apparatus with internal and external screwed or threaded dies by means of which
such corrugated or indented screw threads may be formed.
In carrying out the invention I take the tubes (preferably after being heated)
and pass the ends between dies formed with screw threads which form a spiral
corrugation or thread thereon without cutting into or materially reducing or
impairing the strength of the metal. In a similar way I form a coupling or screwed
sleeve to correspond therewith and fit over the screw thread upon the ends so
formed.
I provide a machine with two sets of dies with thread or screw forming surfaces-
one to fit into the tube and the other to embrace its outer diameter. The screw
forming surfaces of these dies are so formed or rounded as not to cut into the
metal of the tubes or are formed with small runners, wheels or hobs thereon which
will impress the tubes.
The internal die may be in the form of a plug or mandril and the outer dies be
set in slides so that they may be moved to and from a common centre or they may
be carried in a slide or other rest.
The dies are carried or actuated by headstocks or rests of any convenient or
suitable form and a clamping or gripping device holds the tubes while being
operated upon.
I construct the machine either with the thread forming dies to rotate in which
case they are actuated by gearing connected to the headstock which supports them.
Or with the tube to rotate in which case the clamp which grips or secures the tube
is carried by a headstock with gearing connected thereto to give the required
movement.
The joints formed on thin metallic pipes in accordance with this invention are I
consider a better and cheaper joint than any of the joints hitherto formed on this
class of tube.
Dated this 7th day of February 1890
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in or connected with the Joints of Thin Metallic
Pipes or Tubes and in Apparatus for use in the Manufacture
thereof.
I, JOHN MORRIS NEWTON, of Clarence Street, Stalybridge, in the County of
Chester, Mechanical 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 :—
This invention relates to thin pipes or tubes of ductile metal for conveying water,
steam or gas which are not. thick enough or have insufficient substance in which to
cut or chase a screw thread and is designed with the object of forming on the ends
of such pipes or tubes a joint or coupling whereby two lengths may be securely and
effectively connected together.
Although it is usual to make the joints of many tubes or pipes by cutting or
chasing a screw thread thereon it has hitherto been considered impractical to form
a screw coupling for thin pipes owing to the impossibility of cutting a thread
thereon without weakening the tube to such an extent as to render it useless.
This invention consists essentially in forming a joint on the ends of thin metallic
tubes or pipes by means of a corrugated or indented screw thread (not cut or
chased) formed upon the ends of such pipes with a socket or coupling similarly
formed screwed thereon, and in a tool or apparatus which holds the tube and by
means of internal and external screwed or threaded dies forms a corrugated or
indented screw thread thereon.
It will be fully described with reference to the accompanying drawings.
Fig. 1. Longitudinal sectional elevation of hand tool designed for forming
corrugated screw threads upon thin metal tubes according to my invention.
Fig. 2. Longitudinal sectional plan of part of same.
Fig. 3. End elevation of same.
Fig. 4. Longitudinal sectional elevation similar to Fig. 1. modified to be driven
by gearing.
Fig. 5. Elevations of tool and holder which can be fixed in the rest of a slide
lathe.
Fig. 6. Elevation of internal dies or screwed mandrils.
Fig. 7. Sectional elevation of joint made according to this invention with socket
or coupling over two ends of pipes of same diameter.
Fig. 8. Sectional elevation of joint showing coupling end of one pipe fitting into
another of greater diameter.
Fig. 9. Section of tee joint.
Fig. 10. Section of elbow joint.
The tubes A of iron, steel, brass, copper or other ductile metal are preferably
weldless formed in the usual way. The ends of the tubes are passed between dies
or tools having a suitable screw thread formed thereon or set inclined one to the
other to follow a screw thread and by these a spiral corrugation or corrugated
screw thread is formed upon the tube without cutting into or materially impairing
the strength or thickness of material.
The invention may be carried out in several ways either by a specially constructed
tool or in a screw cutting or slide lathe, a small steel tool or die forcing down the
metal of the tube into a corresponding tool or mandril placed inside the tube.
In Figs. 1, 2 and 3 a machine or tool specially designed for working by hand is
illustrated, wherein two sets of dies are provided with screw forming surfaces, one
of which dies forms the internal corrugation of the screw, and the other the
external. It is constructed with a base or stand which carries or supports a
tubular socket C through which the tube A passes and by which it is supported.

page_text: At the rear end of the tubular socket C is a sliding clamp D which grips and
holds the tube A. The clamp D can move to and fro in the socket C and is
prevented turning or rotating therein by the feather or key c, and its outer end is
made tapered with slits or cuts therein over which a tapered clamping nut d is
screwed to hold the tube fast. On the front end of the socket C externally there
is formed a screw thread el corresponding in pitch with the corrugated screw thread
to be formed on the end of the tube A.
Upon the screwed end of the socket C fits a stock, rest or carrier E which carries
the dies which form the external corrugations of the screw thread upon the
tube A. The carrier E is provided with a sleeve e within which an internal screw
thread is formed corresponding to the thread on the end of the tubular socket C.
On the face of the carrier E are pivoted one, two, three or more small dies or
runners which as the carrier E is rotated and drawn in by the screw c' are
rotated round the tube and force the tube into the thread of a mandril or die G
placed inside the tube. The faces of the dies or runners F are formed or rounded
not to cut into the metal of the tube.
The inner side of the corrugation or screw inside the tube is formed by a
mandril or die G which fits the internal diameter of the tube. The mandril or
die G may either be carried forward into the end of the tube as the outer dies F
move over the external surface (the two always retaining the same relative position
to each other) or fit tightly therein and remain stationary with the tube while the
dies F rotate round it or rotate with the tube when the external dies are stationary.
To the face of the stock or carrier E may be bolted a bracket H extending
across the face of it. A stud 9 is affixed to this bracket to which at its other
end the die G is keyed. This may either be a short die with about two threads
upon it, or it may be a mandril the full length of the screw to be made. As the
carrier E is rotated it is drawn forward over the tube by the screw c' when the
dies F on the outside and the die G on the inside together form the corrugated
spiral or screw on the tube.
Referring to Fig. 4 the same tool is shown to be driven by a spur or gear
wheel e from any source of power, the bracket H and stud y being dispensed with
and a stationary mandril substituted.
In Figs. 1-4 the dies or runners F are shown pivoted to the face of the stock
or carrier E on a fixed pin. If desired for the purpose of adjusting or relieving
the pressure the dies F may each be pivoted to a slide on the face of the stock
radiating from the centre and moved to and fro by a screw so that their position
could be easily adjusted.
In Figs. 5 and 6 are shown the die F with a holder F¹ by which it is carried or
supported in the slide rest of a lathe, also the mandrils G which are fixed inside
the tube. When the corrugated screw in the tube A is formed in a lathe, the
mandril G and the tube are secured to the face plate and rotated together and the
die F is carried in the holder F by the slide rest and forced against the tube
impressing the material down into the spiral grooves in the mandril.
Referring to Figs. 7 and 8 two forms of joints are shown constructed according
to the invention, in the former a socket or coupling piece A' is screwed over the
ends of two tubes. And in the latter the end of one tube is screwed into the end
of another of greater diameter. The coupling piece or screwed socket is
formed and screwed in a manner similar to that already described being prepared
from a tube of larger diameter and cut into the required length. It will be
observed that the shape or formation of the screw thread formed on the outside
of the smaller tube corresponds exactly with the internal screw of the coupling or
larger tube and for this reason two sets of dies F and G are made in pairs as shown
in Figs. 5 and 6.
Referring to Figs. 9 and 10 in which a tee and elbow joint or coupling are
shown it will be evident that joints or fittings of thin tube can be made according
to this invention in all shapes such as bends, tees, elbows, crosses, diminishing
sockets, plain sockets, long screws and the like by electric welding whereby the

page_text: parts after being screwed and cut to the desired shape are welded together to forin
the fitting required.
The joints formed on thin metallic pipes in accordance with this invention are,
I consider a stronger and cheaper joint than any of the joints hitherto formed on
this class of tube.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. A thin metallic tube or pipe having a joint or coupling formed by a
corrugated screw or spiral corrugation on the ends of the tubes fitting into a socket
or into the end of a larger tube with similar corrugated screw substantially as
described and shown.
2. A thin metallic tube having a corrugated screw on the end to form in
combination with a similarly screwed socket or the screwed end of a larger tube,
a joint or coupling substantially as described.
on
3. A machine or tool for forming corrugated screw threads or spiral corrugations
thin metallic tubes having a tubular socket to support the pipe, a sliding
gripping device to hold the tube and prevent it rotating, a screw to draw the dies
over the tube, and a stock or carrier to carry dies or tools which impress the tube
and form the corrugations substantially as described.
4. A machine or tool for forming corrugated screw threads on thin metallic
tubes with the several parts constructed and arranged substantially as described
and shown with reference to Figs. 1--3 or to Fig. 4.
Dated this 6th day of November 1891.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.