Improvements in or relating to the Manufacture of Tubes or Tubular Objects.
Year: 1893

page_text: Date of Application, 12th July, 1893-Accepted, 12th July, 1894
COMPLETE
Improvements in or relating to the Manufacture of Tubes or
Tubular Objects.
A communication from EUGÈNE BOULET, of 42, Bd. Bonne Nouvelle, Paris, in the
Republic of France, Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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:-
It is supposed that Figure I represents a plain piece of any suitable metal which
it is intended to form into a tube. An incision a a) made in the said material
allows of opening the piece so as to give it a tubular form (6) and the force
necessary for performing this operation is less than having to drill a hole and force
a punch through it so as to obtain the same result. It is obvious that in the first
instance the tubular form is obtained through deflecting the two sides of the
incision requiring comparatively little power, while in the second case the operation
of forcing the punch through the hole so as to widen it out by drawing the metal
requires much greater power. Moreover the material does not become so much
strained in the first process as in the second.
The present invention is based on the method employed by blacksmiths for
producing a seamless sleeve or ring from a plain piece of metal.
Figure II shows a body of which the section is cruciform. This cross instead
of 4 arms might have 3, 5, 6 or more. If, in this solid body, I make incisions o a
and turn back the lips of such incisions to arrive at the tubular form b, I shall
have obtained a tubular body by a mechanical means realising all the advantages
already described in relation to Figure I.
This method of opening up a solid body by incisions and by throwing back
outwardly the lips formed by those incisions in order to attain the tubular form, is
one of the features which distinguish my mode of manufacturing tubes from other
methods in which the penetration of blanks by punches is employed.
a
In carrying out this process a punch of the form shown in Figure III is used of
which the point is adapted to cut into the metal producing the incisions o
(Fig. 11) by means of sharp edges a represented clearly in the sectional views on
the lines 5-6 and 3-4 of Figure 3. A glance at these sectional views shows that
the punch is arranged in such a manner as to cut into the metal and at the same
time gradually open the cut parts so that in penetrating more and more into the
material the latter assumes gradually a tubular form till it attains its maximum
opening or diameter determined by the sinuous line UV UV &c. more fully
explained hereinafter.
Figure 4 represents a section taken on an axial line showing the application of
this system and
Figure 5 represents a cross section through the same.
M is a hollow socket with a central aperture in the form of an inverted truncated
pyramid and provided with an interior lining formed in sections a a a leaving (as
shown in this case) a central circular hole and having a separate crown c forming
so to speak the continuation of both M and a.
As will be clear from the drawings the three parts M a and c together form a
hollow circular matrix of a uniform section except in the crown c where the hole is
made conical continuing a little into the lining a.
If the rough piece of metal or blank b of the form shown in Fig. 2 (and in
supplementary detail in Fig. 7) provided with a conical head to fit into the conical

page_text: hole of the ring c be inserted in the matrix M a c, the said blank, owing to its
form, offers without slipping sufficient resistance to the penetration of the punch.
A plunger d situated above the matrix is provided with a recess to receive the
lining e and prolonged by the block f, provided outside with four arms, each
terminating in a socket m; the block is also provided with a central hollow or
bore to receive a punch P, which is shown on a larger scale in Figure III; lastly
the bore off in which the punch P is lodged communicates with the part of the
apparatus above the piston d by means of the central vertical channel or tubular
orifices which traverses fe and d through and through, on their axial line. If the
piston or plunger d is connected to the block f, this latter containing the punch I'
which is accurately concentric with the matrix Mac; if the plunger piston d is
driven downwards by a sufficient force upon the matrix, the punch P will penetrate
into the body of the metal blank b, Fig. VII until ƒ meets c, and makes a tight
joint by means of the metallic packing piece t, Figs. IV and VII. At this moment
the punch penetrating no farther, I conduct through the tubular channel s a fluid
under sufficiently strong pressure to enable the punch to overcome the resistance of
the metal. Thus, I say, the tube will be formed.
As shown in Figure III the intersection of the cylindrical stem of the punch with
the cutting edges forms an extensive zigzag or sinuous line UV UV UV.. &c. with
a strongly marked and characteristic outline; and immediately above the said
zigzag or sinuous line UV UV. . etc. is a hollow annular space, due to the fact
that the diameter of the stem of the punch is less than that of the head, as will be
seen from Fig. III and section on line 1-2.
From this construction it results that when the fluid reaches the head x of the
punch P, the head not fitting tightly into the central boring allows the water to
surround the thinner stem of the punch, but only above and following the sinuous
edges UV UV UV. . &c., where, owing to its high pressure, the fluid presses the
sides of the tube energetically against the surface of the matrix.
The friction which would have to be overcome if the tube were ruptured on any
other line than the sinuous line UV UV. . &c. would necessarily be very much
greater than the resistance of the metal of the tube itself, so that such rupture
would only be possible along that sinuous line UV UV. . &c. But the linear
development of the said line may be 4, 5, 6 or an indefinite number of times greater
than the circumference of the tube itself, so that in this manner the strength of the
tube is much greater under this operation than in the process of drawing tubes
through a draw-plate in a bench or machine.
The metal under treatment in front of the punch is subjected to two
forces viz.
1. The friction of the punch against the material.
2. The friction of the material against the walls of the matrix.
The former tends to rupture the blank; it is imperative therefore to reduce this
friction to a minimum by employing a well polished punch, covered with graphite,
kaolin, etc., to render it slippery.
The friction produced between the metal and the matrix tends on the contrary to
retain the material and should be as great as possible, by even roughening the
material when necessary. Lastly one inay apply a counter-pressure at the lower
part of the blank in the direction indicated by the arrow in Fig. VII.
These results are obtained through the improvements which will now be
described.
Figure XXV represents a hydraulic press in elevation,
Figure XXVI a sectional side elevation of the same.
The press comprises the cross-head A, the lower block C, hollow columns B
maintaining the distance between the head and the lower block, A and C, and
adapted to transmit the first the water from the accumulator at high pressure, the
second, the water from the pumps, the third, the water from the accumulator at
low pressure, and the fourth, serving to draw off and pass away the water from the
large cylinder L after it has been used in the operations. The piston or

page_text: plunger A may either be cast in one piece with or otherwise fixed to, the head A
and fitted to a movable cylinder L the latter being provided with a centering
ring and a Bramah packing 2 and adapted to slide on the piston or plunger A'.
The cylinder K is cast with two lugs and fitted tightly into the cylinder L by
means of a Bramah packing 1. In order to ensure the cylinder K against bursting
under the hydraulic pressure it is provided with strong hoops or bands of which
one carries four sockets, to receive bolts J (Fig. XXVI), while an interior lining r
prevents leakage from porosity, which lining may, owing to its form and small size,
be replaced by a larger lining, or in some cases be dispensed with according as it is
required to have a larger or smaller piston d. A special packing is provided so
as to allow any pressure to be maintained up to the limit of elasticity of the three
combined cylinders r K 1.
o and p are two rings supporting the special packing 9; and n, bevel-ended bolts.
lodged in the cylinder K and held fast by the hoops . These bolts by means of
their screw-nuts, sustain the rings o and p, as well as packing 9:
T are tension-bars or links connecting the lugs of the combined cylinders
with the piston cross-head F.
Kl
The
D is a lifting piston working in a cylinder bored in the cross-head A and having
an axial conduit u for the passage of the pressure fluid to the pipes .
pressure fluid is supplied to D by the pipe p¹. The latter piston acts directly on a
cross-head F to which also the two rods T are attached, so as to raise the cylinders L
and K. The pipe ¹ puts the cylinder D in communication with the lower part
of the special packing on the one hand, and with a hydraulic apparatus operating f
on the other (Figs. IV, VI and XXVI). The piston A¹ is provided with a
central chamber Z into which is introduced a compressible fluid which has to be
placed in a suitable membranous pocket or bag, or held up by a sliding or index
piston to prevent its dissipation or its absorption by the water or other fluid
contained in the motor cylinder L.
is a boring or passage for introducing the necessary quantity of compressible
fluid into the chamber Ž. The matrix M has already been described in Fig. IV
and should preferably be provided in duplicate so that while one is in use in the
press, the other may be in hand for either inserting the blank to be treated or for
removing the finished tube (see Fig. XXV). The said matrices are constructed to
slide sidewise in the frame C as indicated in the sectional view Figure XXVI and
may be moved by any suitable mechanical device, such as a piston for instance
operated by hydraulic pressure with a fixed stroke, and adapted to shift the
matrices just to the point required.
In order to simplify the description of the operation I will assume the pressure
fluid admitted into the cylinder D to be water under pressure, that the fluid
introduced into the cylinder » K l is also water and that the compressible fluid in
the chamber Z is simply compressed air.
All the connecting pipes being closed by their cocks, the press is, of course,
motionless.
On opening the outlet pipe B, for the purpose of commencing operations, the
inlet being closed, and B in communication with the open air, the piston D whereof
the cylinder is constantly in communication with the high pressure accumulator,
raises the group of cylinders L and r Kl, driving the water out of the cylinder L
which flows into the reservoir.
When the press is raised to a sufficient height, the discharge pipe B is closed, and
the press becomes motionless. The supply pipe r¹ which is connected to the bottom
of the special packing 9 is then opened, whereupon the water under pressure passes
through the central tube u in piston D, and thence through the special packing y
into the cylinder 1, and presses upon the piston d.
Bolts J fixed to eyes in four lugs cast in one piece with f slide in four sockets in
5 one of the hoops (as already mentioned) and the nuts of those bolts stop the
descent of the piston d at a predetermined point so that there may be in the
cylinder Konly just the quantity of water which is required for the operation.

page_text: This movement is possible when the central tubular opening s of the piston d
(Figs. IV, VII, XI, XXVI) is stopped and d and fare situated as if they formed
but one piece. This is arranged as follows (Fig. VI).
are
Two of the bolts J diametrically opposite to each other, are formed hollow
throughout their length, to serve as cylinders wherein the plunger-pistons
arranged to work (Fig. XXV and XXVI) having their upper ends fixed in the
lugs y cast on the outside of the cylinder L; in such manner that the water passing
down one of the supply pipes (leading from the cylinder of the piston D)
enters the said bolt-cylinders J and exerts downward pressure on the block f
placed between the piston d and crown c (of the matrix) (Figs. IV, VI VII,
XXVI).
If we consider the moment when the piston d has reached the bottom of the
cylinder K, before the latter has had the high-pressure water introduced into it,
the distance between the parts d and f, which is determined by the pressure on the
piston-plungers v, in the bolt-cylinders J, permits of the insertion of a sheet-iron
plate or other such diaphragm of any strength required between d and f. The said
distance or interval between d and f is limited by stirrup-pistons / secured to d
(Figs. IV, VI and XXVI); but these pistons / slide in cylinders g fixed to f
which are connected in such manner as to permit of that connection being cut off
at will, with the bolt-cylinders J by means of the pipes (Figs. IV and XXVI)
which are fitted with distributing cocks, so that as soon as the communications are
opened between the cylinders Jaud 9 the block f will be pressed towards d and the
resisting sheet-metal plate or other such diaphragm between f and d will
hermetically seal the central tubular opening thereof s. For such movement to take
place it suffices that the diameter of the stirrup pistons h be greater than that of the
pistons in the bolts J.
As soon as such tight joint between f and d has been established, the necessary
quantity of water can be admitted into the cylinder » Kl, to effect the operation of
depressing d.
All these preliminary arrangements having been completed, the punch P (Fig. 3)
is put into place at f see Fig. VII where it can be held by any suitable means.
The matrix M (Figs. IV and VI) with the blank 6 inserted in it, is then moved
into the desired position under the press by the means adopted (Figs. XXV
and XXVI). The low pressure cock being then opened, the water ascends through
one of the columns B, by the pipe S, whence it passes through the cross-head A,
the Bramah packings 1 and 2 making tight joints, as shown in the section
(Fig. XXVII) and through the distributing ring S₁ into the cylinder L through
the ports or openings t¹. These ports are arranged, for the distribution of the
water from the ring S (with which they communicate) in the solid cylindrical part
of the plunger piston A¹ and open out at the bottom into the cylinder L, as shown
in Fig. XXVIII which is a horizontal section of A' on the line 7-8 of
Figure XXVI.
The pressure in the cylinder L depresses that cylinder as well as K and with
them the upper cross-head with piston D and attached pipe connections; the
pressure sufficing to cause the punch P to penetrate the blank b under the action
of the hydraulic press (see also Figure VII).
When the block f is on the point of encountering the crown or ring c (Figs. IV,
VI and XXVI) the admission cock of the low pressure water is cut off, and that
of the high-pressure water is opened, this change being automatically effected by
means of suitable tappets, acting on the lever handles of those cocks respectively,
and attached to the movable parts of the press: then comes in contact with c, and
the water already charged into K bears the entire weight of the pressure and
this increased pressure brought suddenly to bear on the stop plate or other
diaphragm between d and which makes a tight joint ruptures the said joint. The
water contained in the cylinder Kl at once exerts its force upon the head of the
punch driving it right through the blank, with the results herein before described in
reference to Figs. IV, VI and VII.

page_text: The punch passes through the metal of the blank, forming it into a tube, and
when it is on the point of quitting the lower end of the tube, the admission of the
high-pressure water in the cylinder L is automatically arrested in the manner to be
explained, so as to avoid the terrible shock which would result; the pressure that
is left to act upon the punch is then only that of the compressed air in the
chamber Z, whereof the volume and expansive power are carefully calculated and
adjusted so that they suffice to expel the punch without shock and so complete the
operation.
The high pressure water is cut off (as above stated) from L as follows;—
The punch is on the point of issuing from the completed tube when the group of
cylinders L and K is lowered to a predetermined height, and at that moment a
stop tappet turns the cut-of cock so as to stop the supply of water to the cylinder L
which is then actuated only by the expansive power of the compressed air in Z.
But as the pipe or distributor supplying water to the cylinder L should have an
orifice of considerable size, it is advantageous to operate this by means of an
auxiliary motor, communicating to the valve itself, or to the distribution slide-valve
rod the movement required to close or open the water admission port of the
cylinder L. This arrangement, e.g. a suitable hydraulic motor, being adopted, the
moving parts of the hydraulic press, such as the piston D, bars or links T, and
cylinder-group L and K l, or any part thereof, may be arranged, at any point of
the stroke, to come in contact with and move the lever-handle of a small distributor
or cock, so as to start the auxiliary motor with a very small quantity of water, and
thus actuate the valve of the distributing device of the cylinder L, so as promptly
to cut off the water supply at the desired moment.
The volume of compressed air in Z is separated from the water in the cylinder L
by a piston X (Figure XXVI shown on an enlarged scale in the section
Figure XXIX). This piston is composed of two stamped sockets 1 and 2 placed
in reversed position with an intervening pocket 3, in such manner that, whatever
excess of pressure there may be whether it be of water or of air one of the
two sockets (1 or 2) must make a tight joint and in case of an equilibrium of
When the excess of
pressure in Z and L, the pocket 3 insulates the two fluids.
When the
pressure is in L, the piston X rises and compresses the air in Z.
admission into L ceases, the expansive power of the air in Z depresses the piston X
and drives the water contained beneath it in L, whereby the expulsion of the punch
is completed.
The cylinders are now raised again in the manner hereinbefore described so as to
allow of removing the matrix from its seat and by pushing the lining A. outward
which offers but little resistance on account of its conical shape and being made in
sections easily opens enough to facilitate the removal of the tube.
The annular piece c Figure IV also permits the tube to be removed as it also is
made with a conical hole.
This operation is rendered possible by the employment of certain essential means
and devices which I will now describe; and 1stly of a special packing q.
It is composed in its upper part of a ring filling the vacant space between
the cylinder and the piston d of which it assures the direction of movement
(Figs. IV, VI, and XXVI); and its lower part consists of a series of packing
rings, superimposed in succession one above another, in any desired number
according to the pressure to be maintained, whether 5, 4, 3, 2, etc. as shown in
Fig. XI and in Fig. XII on a larger scale in section the aggregate of these
packing rings constituting the special packing q, shown in plan in Fig. XIII.
Each of the separate rings or elements of this special packing (generally metallic)
is U-shaped like the well-known Bramah packings, but also each of them is formed
in one piece with a ring which is located within the U of the next following
element beneath itself, the said ring or crown having running through it a conically
bored hole stopped by a conical plug round. the periphery of which is cut a spiral
groove, forming a capillary which permits the passage of the water under pressure.

page_text: Thus I arrange the special packing to operate in such manner that the friction
of the several elements against the piston d is proportional.
From the preceding description it may be seen that the cylinder r K l is charged
with the water derived from one of the tubes », connected with the U of the last
packing ring causing it to form a tight joint, the water under pressure then lifts the
plug & which acts as a valve, making its way gradually upwards and finally fills
the cylinder Kl and acts on the piston d as before described.
The joint between the block f and the annular piece c may be made as shown in
Fig. XXVI or better as shown in Figs. IV & VII where the metallic Bramah
packing t forms an excellent joint for the parts c and f, which are motionless while
the fluid pressure is exerted upon the packing t.
The annular piece c enables a tight joint to be made and communicates all the
pressure of the press to the matrix M so that the lining pieces a are not affected
by the pressure as otherwise they would tend to enlarge the matrix in consequence
of their conical shape and thus rapidly destroy the matrix.
This apparatus for manufacturing various tubes is capable of being modified in
its details and Fig. XXI shows a longitudinal section of a modification in which
the punch e is driven by a piston P (or any other suitable mechanical means) having
a number of rings (one of which is shown in section, on an enlarged scale, in
Fig. XXII and in plan in Fig. XXIII) having Bramah joints at and together
with a valve 6 for decreasing the pressure through passage a in each. The valves b
are held each in a recess e by means of a coiled spring and cause a gradual decrease
in pressure from one ring to another.
The water escapes by the outlet opening a. The effect of the sinuous
line UV UV UV &c. . . . of the punch è is obtained by the pressure of a fluid
introduced by the pipe m and maintained around the punch by the special packing h,
such as above described in relation to Figs. XI and XII. This packing serves also
to strengthen and support the punch and prevent its bending.
As this arrangement is limited by the bending of the punch the matrix y can be
made in one piece below a certain length and in making it slightly conical it will
allow of the tube being forced out by a pressure applied at its lower part in the
· direction of the arrow (Fig. XXI).
In Fig. XIX a tube I is mounted on a mandrel A and held in place by means
of a screw nut J or other suitable means. A draw-plate G (Fig. XVI) fitted to a
cylinder F is provided with a sinuous line UV UV UV (Fig. XVI and Fig. XX,
a section on line 1-2 of Fig. XVI) so that when the tube is engaged in the draw-
plate and pushed by the mandrel A or pulled by the piston C through the medium
of the rod B, the fluid under pressure in the interior of the cylinder F (between
the piston and the draw-plate) compresses the tube against the mandrel determining
the rupture according to the sinuous line UV UV UV &c. but in the opposite
direction to that described in relation to Fig. IV. This method may be utilized
for the process of drawing metal tubes cold. The Bramah packing Ď secures the
tightness of the piston C (Fig. XVI).
Every one is familiar with Muntz's method which consists in drawing a metal
sleeve or socket through the draw-bench, exactly as if it were a solid bar, so that
the elongated bar resembles a tube flattened out into the section Fig. 1, Fig. II,
Fig. XIV or Fig. XV. It might also be of the form of angle iron, or T-iron or
H-iron, or in a word any form which would suit this known method of rolling
or drawing.
Figs. XIV and XV show rolled sections of specially prepared iron for Muntz's
method, but having the following characteristic.
The slits o o produced in the rolled bar by the rolling of the sleeve or socket
leave an uncut thickness o a larger than the thickness of the tube. The said bar is
placed into the matrix and opened by a punch such as shown in Fig. IX and X
and suitable to the form of the blank, its edges coinciding with the angles o formed
through the rolling; while the gradual widening or spreading of the edges of the

page_text: punch presses the corners a against the matrix so that the cylindrical form.
progresses regularly and proportionally as in a forge without producing flaws or
folds in the metal.
The punch shown in Figs. IX and X is also provided with the sinuous line before.
mentioned so as to effect a rapid action and the hydraulic or other fluid pressur..
permits of giving a long stroke to the punch. This process therefore allows of the
rapid formation of tubes from bars by the Muntz' method.
Fig. VIII represents in cross-section a matrix in which the lining a leaves a
groove between every two adjacent sections so as to enable my correspondent to
manufacture Naizereau tubes (wrongly called Serve tubes) without seam and with
external ribs. It is clear that any form adopted in the formation of the matrix
will be reproduced on the exterior of the tube so that my correspondent is enabled to
manufacture tubes with exterior ribs in the form of a spiral or fluted, and various.
other forms in simple or complex style.
When desired the punch shown in Fig. III with an end view in Fig. XVII can.
be provided with grooves running between its cutting edges as shown in Fig. XVIII
(and which are continuous throughout the length of the punch and its stem) so as
to manufacture Naizereau tubes with internal ribs and without seam, the numbers
of cutting edges and grooves corresponding with the number of ribs required in or
on the tube. If the punch represented in Fig. XVII is made accurately there
will be no tendency to twist or turn and the ribs produced in the interior of the
tube will be straight as in the so-called Serve tube, but if all the cutting edges and
the grooves are equally inclined the internal ribs will form spirals and tubes of this.
form may be used with great advantage as boiler tubes or driving shafts.
In ribbed tubes with straight ribs the heat expands the ribs more than the body
of the tube whereby the metal becomes weakened at the intersection of the ribs.
with the body of the tube and causes their rapid destruction.
In the tubes formed by this process with either exterior or interior spiral ribs
the expansion of the ribs increases the resistance of the tube against bursting and
against flattening so that they combine with the advantages possessed by tubes.
with straight ribs also greater resistance greater security &c.
When used as driving shafts these tubes with spiral ribs submit the ribs partly
to tension partly to compression and thereby ensure a great resistance against.
torsion combined with the smallest amount of weight.
The motive agent, which may be water or any other desired fluid, to be used in
the cylinder Kl requires consideration. In some cases water may be used
especially in operating on soft and cold metals. When the metal is harder and has
flaws or is porous the water tends to pass over the sinuous line before described
and it becomes then necessary to soften by heat the metal to be transformed, which.
will mostly suffice. Further, in operating on hot metal it must be remembered.
however that certain metals at once cause certain liquids to assume the spheroidal.
state, while with other liquids those same metals become sprinkled with the liquid.
and these effects may vary for the same metal with the heat and with the pressure
employed. It is necessary, therefore to select suitable temperatures and pressures ;.
also if there should be occasion, to employ mechanical means to cause the perforation
by the punch, combined with suitable pressure to obtain the effect of the sinuous.
line.
Sometimes a mixture or solution is used and even a filling for the grooves in the
punch of any suitable fusible metal or other material so as to receive and transmit
the pressure from the fluid while yet presenting, even in the melted state, an
obstacle to the capillary passage of the fluid across the sinuous line; or lastly to
cause the formation of a precipitate on the tubular body in course of formation so
that a tight joint may be formed along the said sinuous line as its downward
movement progresses.
The process described becomes more economical in proportion to the higher-
pressures used.
If indeed the metal is at white heat the punch cannot remain more.

page_text: than from 6 to 8 seconds as a maximum in contact with the metal while after that
time the surface of the punch becomes softened and damaged. But as there is no
risk during the short time stated the punch passes through the metal without being
materially affected. Moreover in connection with metals which can be welded, the
immense pressure to which the metal is submitted during the formation of the tube
causes a new grouping of molecules as by hammering and if any flaws or other
defects exist in the metal these defects will become welded up as iron or steel
does not require a very high temperature for welding under a strong pressure
and especially if the oxygen is prevented from affecting the surfaces to be
welded.
As a consequence hereof the tubes, iron or steel, manufactured according to this
process are of a great homogeneity which becomes all the more perfect as the
pressure becomes higher.
The process can be applied to the manufacture of pipes and tubes of any form
or description as before stated and enables even new designs to be carried out for
use in connection with hollow driving shafts having internal spiral ribs, or other
objects which are or may be hollow.
The before described apparatus may be modified without departing from the
essential features of the invention.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed I declare that what I claim is ;-
-
1. The manufacture of various tubes or other hollow or tubular bodies by
penetrating a hot or cold blank or solid bar by means of a punch driven mechanically
or by the direct pressure of a fluid causing the said punch to pass through the
body to be transformed in such manner that the tubular portion of the body in
course of transformation receives an internal pressure caused by a fluid such that
the tubular walls as formed are driven against and forced by the said pressure to
adhere to the matrix within which the process of transformation is effected
substantially as described.
2. The combination of the perforation described in Claim 1 with a punch offering
the sinuous line described UV UV... for the purpose of augmenting the resistance
to the force of traction offered by the tube under transformation so that the line of
least resistance and greatest risk of rupture coincides with the said sinuous line
substantially as described.
3. The process of drawing a tube already formed in the manner described in
this Specification or any other tube by means of a punch driven mechanically or
by the pressure of a fluid and causing the said punch to pass through the tube
while lengthening it by pressure against a matrix the said punch being formed with
the sinuous line described whereof the effect is determined by fluid pressure
pressing the tubular body as formed against the matrix substantially as described.
4. Opening and elongating a hollow bar, while regularising its section, obtained
by Muntz' method by means of a punch presenting the sinuous line UV UV UV...
permitting the use of a fluid fixing the walls of the tube against the matrix for
the purpose of augmenting the resistance offered by the tube to the force of
traction during the transformation period substantially as described.
5. The employment for drawing tubes of a draw-plate presenting the sinuous
line described and causing the tube to be pressed against the mandrel by fluid
pressure in such manner that the effective strength of the tube during its
transformation is the resistance along the said sinuous line UV UV substantially
as described and illustrated in the accompanying drawings.
6. The herein described manufacture of tubes having internal or external
longitudinal or spiral ribs.
7. A tube manufactured as described with spiral ribs for use in boilers or
condensers or for hollow driving shafts.

page_text: 8. In connection with and for the purposes of apparatus such as described the-
use of the special packing substantially as described and illustrated in reference to.
Figures 234 23B and 26 of the accompanying drawings.
9. The combination and arrangement of parts constituting the complete tube.
forming apparatus substantially as described and illustrated in the accompanying:
drawings.
Dated this 12th day of July 1893