Improved Method of and Apparatus for Welding Pipes and Tubes.
Year: 1893

page_text: Date of Application, 2nd Dec., 1893-Accepted, 17th Feb., 1894
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Welding Pipes and Tubes.
A communication by CHARLES LEWIS COFFIN, of 986, Jefferson Avenue,
Detroit, in the County of Wayne and State of Michigan, United States of
America, Chemist.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn, in the County
of Middlesex, Civil 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 consists in an improved method of and apparatus for welding
pipes and tubes, hereinafter fully described and claimed.
Figures 1 and 6 are vertical central sections on the line y-y, Figures 2 and 7.
Figures 2 and 7 are vertical central sections on line y-y, Figures 1 and 6,
omitting the frame and hammer actuating mechanism.
Figure 4 is a diagrammatic elevation of a modification adapted to welding
hoops.
Figure 5 illustrates a pipe blank with its edges turned up to afford more metal
at the joint, and
Figure 3 illustrates the welding edges of a tube upset.
Figure 8 illustrates bushings in a cylindrical clamp.
A represents the base of the machine, carrying a series of small rollers E.
B represents a frame secured to and carried on base A. C represents a two part
cylinder, which may be the whole length of a tube or pipe to be welded, or may be
longer or shorter, and this cylinder is cut away along its upper surface, so that it
is not a complete cylinder, as clearly shown in Figure 1, though it will be herein-
after called a cylinder for the sake of brevity.
Cylinder C rests upon the rollers E, and is provided along its underside with a
rack R, into which meshes a gear wheel P, by means of which the cylinder can be
readily moved in either direction along the rollers E. F and F represent ribs
formed on opposite sides of the cylinder C which take into and slide in guide ways
formed in frame B, as clearly shown in Figure 1, by which said cylinder Cis
supported and guided as it moves along on rollers E. G represents a set screw,
having a hand wheel, tapped through frame B, and adapted to bear against rib F',
whereby cylinder C can be slightly sprung and its diameter thus reduced, if the
same should be necessary, to make it fit tightly the article to be welded.
W, Figures 1 and 2, represent a pipe or tube blank which is to be welded: The
interior of cylinder C is intended to clamp the outer surface of said pipe or tube
blank W with considerable snugness, and this may be aided by the set screw G if
the fit is not tight enough. S represents an arm or porter-bar pivoted at one end
to a bracket T on bed A, and carrying at its other end a wheel O, preferably set
in spring bearing a, and an anvil N. The purpose of this bar is to enter the pipe
or tube W and support the anvil close up against the under side of the seam, and
also to carry the lower part of the heating furnace with which the same is to be
heated. For these purposes, in order to compensate for slight inequalities in the
pipe or tube, it is preferable to use the spring bearing a, as shown in Figure 2.
represents a screw shaft threaded through bracket T and with its end swivelled
into arms S, whereby said arm can be raised or lowered. H represents a frame
carried on frame B, in which is supported a steam or pneumatic hammer K directly

page_text: .
above anvil N, the cylinder of said hammer being indicated at J, and also carries
the upper half L of the furnace, which furnace may be an electric furnace, as
indicated by the electrodes r¹, Figure 1, or may be a gas furnace, or kerosene
furnace or any other suitable furnace.
The upper half L of the furnace is carried upon a crosshead 1 which is made
adjustable by the small screw shafts whereby said cross-head L and with it
the upper half L of the furnace may be raised away from the work, or lowered
from the work.
In Figure 4 in which the clamps hold the work consisting of a ring W,
Land M represent the two halves of the furnace which is shown as a gas furnace.
The furnace L M in this case is represented as a gas furnace, the gas coming
through pipe p. With any of this apparatus, when the two edges which are to be
welded are held firmly in proximity or together cold, and then heated to a welding
heat, the expansion of the metal presses the welding edges firmly together, thus
making a weld without the application of extraneous pressure. As the clamps are
not elastic the metal contracts freely on cooling and so there is no strain tending to
open the weld before consolidation.
In Figures 1 and 2, the pipe or tube blank is rolled so that its edges are
practically in contact, and if of very light metal, its edges may be turned up a
little or upset to afford extra metal at the seam, as shown in Figures 3 and 5. The
pipe blank or skelp may be placed cold in the cylinder C when said cylinder is in
the machine or may be placed in said cylinder outside of the machine and then
with said cylinder introduced into the machine in the position shown in Figures 1
and 2. If the cylinder C does not fit the blank closely enough to bring its welding
edges together or in close proximity, said cylinder is slightly pressed by the hand
wheel G until the welding edges of the blank are brought in contact or in proximity.
The upper half L of the furnace is now lowered down in close proximity to the
articles W and heat is applied to the welding edges by any of the means herein-
hefore set forth, and to such a length of the joint as the character of the work
renders advisable. When the edges of the blank are heated to a welding heat, the
blank tends to expand, but this tendency is restricted by the pressure of cylinder C,
and thus by its own expansion, the welding edges are pressed strongly together,
and a weld made. When this has been attained, and while the welding edges are
still hot, the cylinder C and blank Ware moved by means of gear Pand rack R
(or any other suitable means) to bring the welded seam under hammer K and over
anvil N, when the weld may be hammered if desired. It is not necessary to bring
the edges of the skelp in actual contact, though generally preferable to do so.
Welds have been made in this manner with the edges nearly one-eighth of an inch
apart when cold.
In Figures 6, 7 and 8, the apparatus is practically the same as that above described;
the clamp, however, shown in these figures, differs from that of the other figures
in being made in two halves, and therefore adjustable, and the mechanism for
noving the work is different.
Crepresents a two part cylindrical clamp, one part (marked C) being stationary
as to the other part, while the other part (marked C) is capable of motion to and
from the stationary part and may be pressed strongly towards the stationary part
by means of a hand wheel G and screw shaft pressing against a rib F' which slides
in a guide way in frame B, the other part C of said clamp having a similar rib F
sliding in an opposite guide way. The stationary part is prolonged under the
movable part and is provided with a long threaded sleeve engaging with a screw
shaft u, by which the clamp C may be made to traverse backward and forward
along bed A. The upper edges of the two parts of said cylinder clamp are cut
away as shown in Figure 1 to expose the metal held in said clamp at the working
point, Grepresents a screw shaft threaded through a lug on the lower part of the
stationary part C of the clamp and engaging with the movable part C of the clamp,
whereby the movable part may be moved to and from the stationary part.
may be additional to hand wheel G or may be used alone.
This

page_text: V.V represent bushings to be inserted in cylindrical clamp C C' for the purpose
of adjusting the same clamp to tubes of varying diameters. R R, Figure 8,
represent guard strips which may be of any desire.l material, removably secured to
the edges of cylindrical clamps Ċ C', to protect the same against the effect of the
heat in the welding operation, and these guard strips may be readily removed and
new ones substituted.
In working thin metal tubes it may be desirable to clamp them to the interior of
the clamp CC, and this can be done by the angle iron clamps J', Figure 6,
connected with screw bolts passing through the interior of the clamp so as to force
the material W firmly against the clamp. It will of course be understood that in
welding a thin tube, the screw bolts of clamps J' will pass through the clamp C C
beyond the ends of the tube and the angle iron will project into the tube. These
clamps, by holding tube firmly against the interior of the clamp C C, tend to
prevent buckling of the metal when subjected to compression strain, either by
expansion strain or in any other manner.
25
While as described the operation consists in bringing the edges to be welded
in contact, it is not meant that they must be absolutely in contact, but they must
be sufficiently near to each other so that expansion of the heatel parts will cause
the edges to come in contact and press together, the word " contact when used
in this Specification is to be construed in this sense. The word "cold" is used
in this Specification and claims in a comparative sense only, and means any
temperature which is below a welding heat, and said word "cold" as used in this
Specification is to be so construed.
Welding by this method can proceed at a rate which is governed only by the
capacity of the furnace to heat the edges of the blank to a welding heat, and in many
cases may be so rapid as to permit of a steady movement of the cylinder Cand blank W
through the machine.
It is not essential that the clamp should be a cylinder. Any form of clamp which
will hold the edges of the skelp firmly in position may be used.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is-
1. The herein described mode of welding pipes or tubes consisting in bringing
the edges to be welded in proximity while cold, holding the pipe back of its edges
in position against expansion strain, and then heating the edges to be welded to a
welding heat.
2. The herein described mode of welding pipes or tubes consisting in clamping
the pipe with its edges in proximity when cold, raising the temperature of the parts
to be welded to a welding heat, whereby the expansion of the metal presses the
welding edges together, and finally finishing the weld by rolling, hammering or any
other desired manner.
3. The herein described mode of welding pipes or tubes consisting in clamping
the pipe to be welded with the welding edges in contact when cold, raising the
welding edges to a welding heat, resisting the tendency of the heated metal to
expand, and permitting said metal to contract freely as it cools.
4. In an apparatus for welding pipes or tubes, the combination of a clamp for
holding said pipe rigidly against expansion and a furnace for heating the edges to
be welded, substantially as and for the purposes set forth.
5. In an apparatus for welding cylinders a hollow clamp adapted to receive and
compress the cylinder to be welded and means for heating said cylinder along the
cylinder substantially as shown and described.
6. In an apparatus for welling pipes and tubes the combination with the cylinder C,
means substantially such as described for slightly compressing said cylinder,
blank W within said cylinder, and a furnace L M adapted to heat said blank along
the joint, substantially as shown and described.
7. In an apparatus for welding pipes or tubes, the combination with a cylinder C,

page_text: means substantially such as described for slightly compressing said cylinder and
furnace L M adapted to heat said blank along the joint, a reciprocating hammer
adapted to hammer the welding seam, and an anvil carried within the blank
substantially as shown and described.
8. In an apparatus for welding pipes or cylinders the pivoted arm S carrying the
anvil N and supported by the roller O journalled in spring bearings, substantially
as and for the purposes set forth.
9. The herein described method of welding thin metal consisting in turning up or
upsetting the edges to be welded, clamping the metal with said edges in proximity
while cold, and then heating the edges to a welding heat.
10. The herein described mode of welding tubes, consisting in bringing the edges
to be welded in proximity while cold, holding the tubes in that position against
expansion strain, and then heating the edges to be welded to a welding heat.
11. The herein described mode of welding pipe, consisting in clamping the pipe
with its edges in proximity when cold, raising the temperature of the parts to be
welded to a welding heat, whereby the expansion of the pipe presses the welding
edges together, and finally finishing the weld by rolling, hammering, or any other
desired manner.
12. In an apparatus for welding a tube, the combination of a clamp for holding
said tube rigidly against expansion, and a furnace for heating the tube to be welded,
substantially as and for the purposes set forth.
13. In an apparatus for welding metals, the combination of a separable clamp for
holding said metal rigidly against expansion and a furnace for heating the metal to
he welded, substantially as and for the purposes set forth.
14. In an apparatus for welding cylinders, a hollow separable clamp adapted to
receive and compress the cylinder to be welded, and means for heating said cylinder
along the seam, substantially as shown and described.
Dated this 1st day of December 1893.
WM. P. THOMPSON & Co.,
Agents for the Applicant.