Wrought Metal Tubes and the Resulting Round End Tubes.
Year: 1887

page_text: Date of Application, 27th Aug., 1887
Specification Accepted, 13th Jan., 1888
Wrought Metal Tubes and the Resulting Round End Tubes.
We, JOHN PATTERSON KENNEDY and EDWARD SELDEN TOWNSEND KENNEDY, of
716 East Thirteenth Street, in the City and State of New York United States of
America, Manufacturers, 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 the method of and machine for closing the ends of wrought
metal tubes, by first swaging the metal and then welding it directly upon itself, so as
to form a seamless, rounded end of thickened metal, capable of standing a high
pressure; also to the round end tube produced by the method and machine.
We will first particularly describe our improved machine, and then set forth in
detail, our method of forming a perfectly welded closure of the tube.
In the accompanying drawings, Figure 1, represents a side clevation of the machine,
properly mounted on its base and with the feed gears arranged on its opposite sides.
Figure 2, represents a front elevation, on an enlarged scale, with the base and feeding
machine removed. Figure 3, represents a vertical section of figure 2. Figure 4,
represents a side elevation, on enlarged scale, of the tube feeding mechanism.
Figure 5, represents an end view. Figure 6, represents a top view thereof. Figure 7,
represents a front view of the feed nut. Figures 8 and represent the finishing
mandrel and die. Figure 10, represents a sectional view of the finished tube, with a
welded, seamless, and rounded end of thickened metal. Figure 11, represents the
tube with contracted end as swaged in the machine. Figure 12, represents an
elevation, partly in vertical section, of a radial tube boiler, to which my improved
wrought metal tube is applied.
In figure 2, the outer flaring openings of both sets of dies are, for convenience of
illustration, shown on the same side of the machine, but in practice they would
generally be arranged to face in opposite directions, as in figure 1, where the feed gears
are also mounted on opposite sides of the machine, so that both can be more con-
veniently operated at the same time. The dies can readily be slid by their tongues,
into the dove-tailed grooves forming their seats so that their large openings shall face
in either direction, that is, to the right or left.

page_text: The frame A, and the bed plate A'.supporting the working part of the machine,
are preferably made of cast iron and rest upon the iron or other base B, at a suitable
height for convenient manipulation. Suitable journal boxes C, CC are arranged at
the tops of the frame plates A, and in them is journailed the shaft D, having
the eccentrics, or short cranks d, d¹ to which are connected, through the
medium of suitable brass boxes, straps bolts, and keys, the connecting rods E. In a
machine of a suitable size for my purpose, a steel shaft D, is used, three inches in
diameter, and is turned down at the eccentrics to two inches diameter, so as to give
one inch throw or stroke to the connecting rod and die. The shaft D, is provided
with a fly wheel H, and a belt wheel I, shown in figure 1. The cross-head F, having
suitable lugs with eyes, is bolted to rod E, so as to form a suitable joint, and is
provided with an opening y, to make it lighter. Water may be run in this opening
to cool the cross-head. The sides are provided with vertical guide tongues f, which
fit and slide in the grooved guideways a, bolted to the frame A. The lower face of
the cross-head, is provided with a longitudinal dove-tail groove h, into which is fitted
the dove-tail tongue g, of die G, and is secured therein by the key i, thus rigidly
connecting the die with the cross-head. Die G, is provided in the lower face, with a
concave or semi-conical cavity e, which however does not end in a point, but in a
small semi-cylindrical opening. The lower die K, is rigidly secured, by means of its
dove-tail tongue k, and a key, in a dove-tail groove of the bed plate and like die G,
is provided with a concave, or approximately semi-conical cavity e'. The contour or
surface of the cavity is not regular, but is hollowed or bellied more at the middle
portion, and then converging into a passage and semi-cylindrical opening, as shown
in figure 3. A stop plug may be placed in the passage to arrest the tube being
swaged.
The feeding gear for gradually and regularly forcing the end of the tube to be
swaged and welded into the dies is shown in position in the machine on each side of
the frame, in figure 1, and in enlarged detail, in figures 4 to 7 inclusive. The whole
gear is secured to the frame A, of the machine, by bolt bars L, L' which are themselves
riveted or bolted to the frame, and upon their outer ends, carry the large feed nuts M,
as shown in figure 1. The feed nuts M, are provided, upon opposite sides, with large
ears or lugs m, having bolt holes c, as shown in figure 7, and are internally screw-
threaded for receiving the feed cylinders N. They are slid at bolt holes c, upon the
screw threaded ends of bars L, up to shoulders upon said bars, and are secured in
position by small nuts 1, about six inches from the front sides of the dies.
Bolt bars L, L' are secured to the intermediate vertical plate, as well as to the end
plates of the frame A, in the same horizontal plane, so that the bar L' which is bolted
to the intermediate frame plate, is seen in figure 1, extending to the right on a line
with bar L. Bar L' and a similar bar bolted to the farther end plate of frame A,
support the right-hand feed gear shown in figure 1, at the farther end of the machine,
for feeding tubes to a second set of dies beyond the set fed by the left hand gear at
the near end of the machine. The left-hand feed gear is supported by the bar L,
bolted to the near end plate of frame A, and by a similar bar, boited to the inter-
mediate frame plate, and like bar L, extending to the left of the frame. The two
end frame plates and the intermediate or middle frame plates are clearly shown in
figure 2.
The feed cylinder N, the guide-ways P, P¹ and the hand wheel, are cast in one
piece, and the cylinder is turned true and externally screw-threaded up to a shoulder
near its outer end. The guide-ways P, P' are provided with longitudinal dove-tail
grooves, p, p¹ extending from their outer ends to the inner periphery of cylinder N,
as shown in figures 5 and 6, for receiving the toothed gripping jaws V, VI which are
made to slide freely in the grooves. The hand wheel is connected by spokes n" with
the end of cylinder N. The outer end of cylinder N, is provided with a raised
annular rim n, and upon
the end face of the cylinder and over this rim, there is fitted by
a flange the slotted ring R, so that it may freely turn thereon. The ring is provided
upon opposite sides with the eccentric slots r, 1. Bölts t, t, screw-threaded at their
ends, are passed through these slots and screwed up to their shoulders into the jawsV,V'.

page_text: The outer ends of the bolts are provided with heads or with nuts v, which, being
placed in position, hold the slotted ring loosely upon the end of the cylinder, since
the jaws are held in their dove-tail grooves p, pl. It will be seen that the ring is free
to rotate to the extent of its eccentric slots, and that the jaws are slid out and in, a
distance equal to the eccentricity of the slots. The ring R, is provided with a boss p"
having a screw-threaded hole into which is screwed the operating handle o, shown
in figure 1. The hand-wheel n' may also be provided with radial handles o'.
For smaller-sized tubes than those to which feed cylinder N, is adapted, a suitable
cylindrical bushing having its walls tapering internally to the proper sized opening,
is slipped into the inner end of the feed cylinder N. Gripping jaws, adapted to
smaller tubes, may be substituted for those here shown, so that tubes of various sizes
may be worked in the same machine. The jaws can be readily removed, by with-
drawing bolts t, and different ones inserted. For smaller tubes, the serrated end of
each jaw would be made with a smaller curve, adapted to the size of the tube, and
the bolt holes would be so placed that the jaws, when in position, would be thrown by
rotation of the slotted ring R, to firmly grip the tube. For smaller tubes, the jaws
would have to project, when retracted, a short distance into the feed cylinder, as the
extent of their movement by the slotted ring would remain the same.
In figure 2, the left-hand upper die is shown at the end of its downward stroke, in
which position it stops short of the lower die, leaving a space between them which,
in the working machine, amounts to about one-quarter of an inch. The right-hand
upper die is shown at the end of its upward stroke. The dies are given one inch
throw at each revolution of shaft D, and the shaft is made to revolve very rapidly
(making from 550 to 650 strokes per minute) so that short quick blows are given to
the tube end being swaged.
Though but two sets of dies are shown in position in the machine, any desired
number may be used by arranging them in a line, and extending the main shaft.
Figure 12, illustrates the type of a steam boiler to which we apply our improved
wrought metal, round end tubes. The general features of the boiler and its furnace
are not herein claimed, but only the application of our particular tube to this type of
boiler. The boiler enclosing shell H¹ is provided internally with grate D¹, combustion
chamber E, and deflector F. Door frames u, u are secured in the furnace walls
and form openings leading to the fire box and ash pit. Sight holes and closing
doors are provided in any desired number in the furnace walls, to give access for
cleaning dust and ashes off the outside of the tubes. The central boiler cylinder, or
stand-pipe B, receives the radial tubes a, around its entire circumference.
A man
hole b, is formed in the base of the stand pipe, and steam pipe I' leads from its top.
My method and machine are particularly adapted for closing the ends of wrought-
iron or steel tubes, suitable for use with any form of radial tubes or porcupine boiler.
In such boilers, it is essential that the tubes shall have their ends closed with seamless
welded metal, preferably thickened and of rounded or hemispherical form, so that the
tube shall be extra strong and durable at such point, and be free from crevice or
irregular depression, in order that the circulating water shall scour the surface and
prevent deposit of dirt, which would cause injurious over-heating and burning of the
metal.
To fulfil these requirements and to overcome the objections to, and defects of, tubes
heretofore made, we employ our improved method of effecting the welding of the
metal directly upon itself, as follows:-
The tube x, having been cut to the required length, is heated at the end, to the
proper temperature, and is inserted in the feed cylinder N, so as to project at its inner
end a sufficient distance to enter the dies, and the gripping jaws V,V' are then quickly
forced to grasp it, by turning the slotted ring R, into the position shown in figure 5.
The upper die, now being in operation, feed cylinder N, is turned in the threaded
nut M, as fast as necessary, and the tube thereby advanced between the dies and
turned therein, while it is uniformly subjected to the swaging operation of the dies,
till it is suitably contracted and, if desired, made to conform to their shape, the metal
being compressed centrally at the conical tube end, into a short projecting nipple, as

page_text: shown in figure 11. The swaging by the semi-conical dies being completed, the
jaws V. V are opened and the tube withdrawn, and afterward the feed cylinder is
run back to the desired position. By means of the feed gear, the tube is fed forward
and rotated in the die in a positive, regular manner, so that it is neatly and uniformly
swaged to the conical form with a projecting nipple, and finished, so far as the
operation of this machine is concerned. This operation, though neatly and
expeditiously performed, does not produce a perfectly closed and welded end, and
further means are required to produce a tube having a welded, seamless end of
thickened metal of rounded or hemispherical form, adapted to my purpose. The
extreme end of the tube is accordingly re-heated to a welding heat, and the tube is
then slid down over the rounded or hemispherical end of a mandrel T, and by rapid
blows with the cupping tool or swage S, having the hemispherical depressions, the
nipple and conical end are quickly worked down into the thickened, rounded and
solid end, shown at c, in figure 10, without seam or joint, and having a smooth,
regular, hemispherical, inner surface, which will be effectively scoured and kept clear
of dirt, by circulating water, when in practical operation.
We have learned, by careful experimental practice, that a satisfactory welded tube
end cannot be formed with semi-conical or hemispherically hollowed dies, operating
upon the end of the tube, without a mandrel; that, by such an operation, the metal
of the tube is more or less drawn and wrinkled internally into irregular shapes and
cavities, and that a tight weld is not formed. Neither can a satisfactory weld and
closure, be effected by the sole use of a round-ended mandrel and a cupping die having
a semi-cylindrical cavity, and operating upon the uncontracted end of a tube over the
mandrel. The tube end must be first swaged and contracted to an approximately
conical form by the concave semi-conical dies, and then welded and finished with the
mandrel, having a hemispherical end and the cupping tool, having a hemispherical
cavity, in order to form a perfectly welded, seamless, rounded end of thickened metal,
adapted for use in a high pressure porcupine boiler.
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. The herein described method of closing the ends of wrought metal tubes, which
consists in heating the end of a tube to a proper working heat, then subjecting it to
the swaging action of semi-conical or concave dies till the end is suitably contracted,
then re-heating the end and sliding the tube upon a mandrel, having a rounded or
hemispherical end, and by means of a suitable die, swaging and welding the tube end
into a rounded form, without seam or joint, for the purpose described.
2. The herein described method of closing the ends of wrought metal tubes, by
welding the metal directly upon itself and forming a rounded, seamless end of thickened
metal, which consists in suitably heating the end of a tube, then feeding it forward
and rotating while it is subjected to the swaging action of a pair of semi-conical or
concave dies, till a conical end is formed, then re-heating the end and sliding the tube
upon a mandrel having a rounded or hemispherical end, and then, by means of a die,
having a concave rounded recess, swaging and welding the tube end into a rounded
hemispherical form of thickened metal without seam or joint, for the purpose
described.
3. In a machine for welding the ends of wrought metal tubes, the upper and lower
dies, having semi-conical cavities with extended, small, semi-cylindrical passages and
openings for forming a conical end and a projecting nipple on the tube, in combination
with mechanism for operating the upper die and a feed gear, in the manner
described.
4. In a machine for swaging the ends of wrought metal tubes, the upper and lower
die sections, each having a semi-conical cavity with extended, small, semi-cylindrical
passage or opening for forming a conical end, and a projecting nipple on the tube to
he swaged.
5. In a machine for welding the ends of wrought metal tubes, the dies, provided

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ith cavities and openings, as described, in combination with the cross-head connecting
ith the upper die, and having guide tongues, the guide-ways secured to the frame A,
he main shaft having an eccentric and a connecting rod, for the purpose described.
6. In a machine for welding the ends of wrought metal tubes, the cross-head F,
aving the lateral guide tongues f, f, and a dove-tail groove in its bottom face, in
ombination with a die having a dove-tail tongue secured in the groove by a key,
guide-ways upon the frame, and the operating shaft and connecting rod, for the purpose
lescribed.
7. In combination with the dies for welding the ends of wrought metal tubes and
operating mechanism, the feed gear adapted to feed the tube forward and rotate it in
the die during the swaging operation, as described.
8. In a machine, having dies for swaging and welding the ends of wrought metal
tubes, the feed gear consisting of a fixed screw-threaded feed-nut, and a screw-threaded
feed cylinder, operating in such nut, and having means for holding the tube within it,
for the purpose described.
9. In a machine for welding the ends of wrought metal tubes, the feed nut properly
secured in front of the dies, in combination with the feed cylinder working in such
nut, and having sliding toothed jaws and means for operating such jaws, for causing
them to grasp or release the tube, substantially as described.
10. In combination with the feed nut, the feed cylinder having dove-tailed guide-
ways and toothed jaws fitted to slide therein, and the ring R, provided with eccentric
slots, connected by bolts to the jaws, as and for the purpose described.
11. In a machine for welding the ends of wrought metal tubes, the feed nut rigidly
secured by bars L, to the frame of the machine, a suitable distance in front of the
die, in combination with the feed cylinder, provided with mechanism for gripping and
holding the tube while it is being operated upon the dies, as described.
12. In combination with the feed cylinder, the flanged ring R, fitted to the end
thereof and having eccentric slots r,, engaging with the bolts t, t, in the sliding
jaws V, V, as and for the purpose described.
13. The feed cylinder having the guide-ways P, and the hand wheel n³, all cast in
one piece, as and for the purpose described.
14. A wrought metal tube for boilers, having its end wall closed and welded directly
upon itself and of a rounded or hemispherical form, for the purpose described.
15. A wrought metal boiler tube, having its hemispherical end closed by the metal
welded upon itself, and such end made gradually thicker from the circuinference to
its centre, for the purpose described.
16. A wrought metal tube for boilers having its end wall closed and welded upon
itself in a rounded or hemispherical form, and the end portion made-thicker than the
cylindrical wall of the tube.
17. In combination with a boiler cylinder, the radial water tubes, having closed
seamless, rounded ends of thickened metal welded upon itself, for the purpose
described.
18. In combination with any form of porcupine boiler, the wrought metal water tube:
having closed, welded, seamless en'ls with smooth or even inner surfaces of round or
5 hemispherical form, whereby, in operation, the water will uniformly scour the inside
of the tubes, thus preventing deposits of dirt and consequent over-heating and
destruction of the metal.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicants.