A Process of and Apparatus for Manufacturing or Treating Metal Tubes.
Year: 1897

page_text: A Process of and Apparatus for Manufacturing or Treating Metal
Tubes.
I, RALPH CHARLES STIEFEL, of Ellwood City, Lawrence County, in the State
of Pennsylvania, United States of America, 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:
My invention relates to the making of seamless metal tubes which may be
straight and parallel or which may vary in thickness at different portions of their
lengths and consequently in their interior or exterior diameters, or both, as the case
may be, preferably the tubes having straight parallel exterior sides and a uniform
outside diameter with any variations of thickness on the inside and a consequent
variation of the inside diameters.
Its objects are to draw tubes upon solid mandrels, then cross roll so as to release
them from the mandrels the result being that even though the mandrel is
not of uniform diameter throughout its length, it may be extracted from a tube
which has been drawn upon it through the drawplate or die of a draw bench, the
interior of the tube conforming exactly with the shape of the mandrel and embrac-
ing it with strong contact.
The accompanying drawings show a preferred form of mechanism for carrying
out my invention and illustrate some of the steps of the process which I follow.
These are in the best form now known to me but certain changes that would
be obvious to a skilful mechanic might be made in the details of the mechanism
and in the exact steps of the process without departing from the spirit of my
invention as set forth.
Figure 1 is a plan view of my cross-rolling mechanism partly in section on the
line 1, 1, of Figure 3.
Figure 2 is a vertical transverse section through the same on the lines 2, 2, of
Figures 1 and 3.
Figure 3 is a vertical longitudinal section of the same on the lines 3, 3, of
Figures 1 and 2.
Figure 4 is a vertical transverse section on the line 4, 4, of Figure 3.
Figure 5 is a vertical longitudinal central section through the cylindrical portion
of the frame which supports my mechanism.
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page_text: Figure 6 is an end view of the same.
Figure 7 is a similar view showing some of the operative parts in position.
Figure 8 is a central longitudinal section through the cylindrical guideways of
the rolls.
Figure 9 is an end view of the same.
Figures 10, 11, 12 and 13 are diagrammatic views illustrating certain steps in
the process of the formation upon solid mandrels of tubes having straight parallel
exterior sides with varying thicknesses and consequent varying internal diameters.
It is usual in the art of making seamless metal tubes to reduce their diameters
and increase the length by drawing them through dies or drawplates the apertures
of which are smaller in diameter than the tubes presented to them, a bulb located
within the pass of the drawplate, acting upon the interior of the tube simul-
taneously with the action of the drawplate upon its exterior. While this process
produces satisfactory results, it is necessarily slow for the reason that the tube
can only be reduced in thickness to a very small extent at each drawing operaton
owing to the fact that its shell is not sufficiently strong to overcome the frictional
resistance of the drawplate and of the stationary bulb. or mandrel resulting from a
heavy reduction, which if attempted would result in the tube being torn asunder.
I have discovered that if the tubes are drawn upon mandrels, that is if the tube
and the mandrel together are drawn through the die, the amount of reduction pro-
duced may be several times greater than where the tube alone is drawn through
the die and over a stationary bulb for the reason that the mandrel within the tube
and upon which it is compressed by the die will take up and carry a large propor-
tion of the end pull or strain necessary to draw the tube through the die and for
the further reason that the frictional resistance to the passage of the tube that
is offered by the usual fixed bulb within the tube at the drawplate is eliminated.
The obstacle which I have encountered in drawing tubes upon mandrels has been
the difficulty of extracting the mandrels from the, drawn tubes, the drawing pro-
cess causing the tubes to embrace the mandrels with a frictional tenacity very
difficult to overcome.
While this result has been an obstacle in the way of drawing plain straight
tubes upon plain straight mandrels it pertains with much greater force in the
making of tubes of varying thicknesses upon mandrels of varying diameters,
particularly so in the case of tubes made thicker at both their ends than at their
central portion, for the reason that the mandrel embraced by the central thin
portions of the tube is larger in diameter than the interior diameters of the end
portions of the tubes.
In order to extract the mandrels from such tubes it is essential not only to
loosen the tube along the entire length of the mandrel but to increase the diameter
of one or both ends of the tubes to an extent that will admit of the passage of the
larger central portion of the mandrel.
My invention contemplates a cross-rolling device and process that will success-
fully accomplish this object and render the manufacture of such tube an easy
commercial possibility.
In the practice of my invention tubes of any kind after being drawn through the
dies with a mandrel inside of them are subjected to a cross-rolling process which
stretches them laterally and enlarges their diameters. This is effected by passing
them between opposed rolls, the axes of which lie in planes substantially parallel
to each other and to the pass, the rollers compressing the walls of the tubes against
the mandrel with such force and effect as to stretch them laterally, that is in a
direction at right angles to the axis of the tube, which is thus enlarged in diameter,
releasing the mandrel from its close embrace.
To accomplish this with sure commercial results I have devised the mechanism
shown in the drawings in which A, is a cylindrical frame or housing, the longi-
tudinal centre of which is intersected at its mid-length by the axis of the pass,
in which the work of the mechanism is accomplished. This frame has large

page_text: openings a, in its sides in line with the pass to permit of the passage through it
of the work to be operated upon.
Fitting into this frame at its ends are cylinders B, and C, having shoulders or
enlargements at their outer ends which bear against the abutments b, and c, in the
frame A. Enclosing the ends of the cylindrical frames are caps or covers D, and E,
secured to the flanges d, and e, of the frame by suitable stud bolts as shown in the
drawings. These covers close the open ends of the cylindrical frame and hold
the cylinders B, and C, firmly against the abutments b, and c, so as to provent their
endwise movement.
The outer ends of the cylindrical frame A, are cut away at their top sides so as
to expose the outer ends of the cylinders B, and C, which ends are covered and
pressed upon by caps F, and G, held to the frame by stud bolts f, and g, by means
of which the said caps may be pressed with any desired degree of frictional contact
upon the ends of the cylinders B and C, to hold them positively, in any position to
which they may be adjusted, against accidental rotation. The inner faces or walls
of the cylinders B, and C, are provided with longitudinal guide-ways b', and c¹,
in which are fitted roll-frames H, and I, extending across the cylinder and pro-
vided with side extensions h, and 2, in which are located the bearings of the
rolls J, and K. The frames H, and I, may reciprocate freely in the guide-ways
of the cylinders B, and C, so that the rolls J, and K, may be moved towards or
away from each other independently of any motion of the cylinders.
The axes of the rolls however may be adjusted to any angle relatively to each
other or to the axis of the pass by loosening the binding caps F, and G, and revolv-
ing the cylinders to the desired point where they may again be locked by scrowing
down the caps.
In order to secure accuracy in such angular adjustments of the rolls I may put
u graduated scale or series of marks on the outer ends of the cylinders or on the
outer faces of the binding caps F, and G, with an index mark as indicated in
Figure 7. The shafts of the rolls J, and K, extend beyond their bearings and are
provided with universal joints or couplings j, and k, to which are connected tumbl-
ing shafts, and k, which may be driven in any suitable manner and which
rotate the rolls J, and K, in the direction indicated by the arrows thereon. The
pass in which the work is performed lies between these rolls and as the rolls are
movable towards or away from each other the width of the pass may be adjusted to
adapt it to varying sizes of work.
When the rolls are set straight, that is with their axes in a plane common to
themselves and to the axis of the pass, they would simply revolve and compress
laterally any work placed between them but would not impart any endwise motion
to the work.
When it is desired to have them feed the work endwise the cylinders B, and C,
are revolved so as to incline the axes of the rolls J, and K, in opposite directions,
when, upon proper angles being attained the cylinders are locked by the binding
caps and hold the rolls in the positions to which they have been adjusted. While
both of the rolls are movable bodily towards or away from the centre of the pass,
the roll J, is movable only for the purpose of adjusting its position to varying
sizes of work, it remaining in a fixed position when once adjusted for a certain
class of work and is only moved when work of another size is to be produced.
To effect its adjustments a screw L, passes through the cap D and bears against
the back end of the sliding frame which carries the roll J, pressing it towards
the pass and holding it in its desired position. The roll K, however is free to
move backwards and forwards within certain limits at all times and within these
limits, it is subject to constant pressure, urging it towards the opposed roll and
producing the necessary compression upon the work effecting the purposes of my
invention.
This pressure is preferably a yielding pressure such as that of a spring, lever
or ram, the amount of which pressure may be easily and quickly regulated to adapt
it to the character of the work to be performed, the pressure being much heavier

page_text: and the work of the rolls more aggressive upon the thick walls of a tube than upon
thinner walls.
In the drawings I have shown a spring N, to produce this pressure but as just
stated other means may be employed. A hollow screw 0, passes through the
frame cap or cover E, and a bar or plunger l', fits into the smooth bore of this
screw and is free to play backwards and forwards therein, its front end bearing
against the movable frame I, which carries the roll K.
A solid flange or collar p, is formed on the plunger just beyond the head of the
screw O, and comes in contact with the end of the screw at the extremity of its
forward movement. The position of the screw is so regulated that the roll may
be urged forward just far enough to act upon the walls of a tube and not far enough
to spring forward and come into contact with the projecting end of the mandrel.
when the end of a finished tube has gone through the pass.
The rod or plunger P, extends beyond this collar and through a cross bar or
guide Q, which is held in position by bars 9, screwed into and extending from the
cover E, attached to the head of the main frame. The end of the plunger P,
passes through a hollow screw R, which is screwed into the cross bar. Between
the end of this and the flange p, is located the spiral spring N, which gives the
roll K, its forward impulse.
This spring is wound about the plunger and bears at its ends against washers n, n,
resting against the flange or collar on the plunger and the end of the screw R.
The pressure or force of the spring is governed by the screw R, the screwing for-
ward or backward of which increases or decreases the force of the spring, and the
forward movement of the plunger is limited as before stated by the screw 0.
If smaller or larger work is to be operated upon without variation of the spring
pressure both of these screws are moved forward or backward together, while the
movement of the screw R, alone varies the spring pressure without regard to the
size of the work to be performed. The work whilst in the pass should be sup-
ported by suitable guides. I prefer to use a roller guide S, like that indicated in
the drawing, the axis of which extends in the same general direction as the axes
of the pass and of the compressing rolls.
When the axis of this roller guide is parallel to the axis of the pass, the roller
simply revolves with the work which slips along its upper surface. In order to
avoid this slipping contact however I provide for inclining the axis of the roller
relatively to the axis of the pass so that instead of sliding upon the roller, the
work will be assisted thereby in its endwise movement, as shown in Figure 1.
This roller is mounted in suitable bearings, on the ends of a head or cross bar T,
and is supported at its centre directly beneath the centre of the pass by an
additional bearing s¹.
The cross bar is formed with a spindle t, mounted in a lug U, and having its
axis which is vertical intersecting the point X, common to the axis of the pass
and to the axis of the cylinders B and C, which support the compressing rolls.
A screw V, passing through a lug v, from the frame bears against the lower end
of the spindle t, for the purpose of adjusting and holding it and the guide roller
which it supports, at any desired elevation. A clamping screw u, passes laterally
through the lug U, and bears against the spindle t, to hold it against accidental
rotation.
It will be observed that all the axes of the working portions of the machine
converge on the axis of the pass at the line X, the axes of the cylinders B, and C,
intersecting the centre of the pass horizontally and at a right angle thereto while
the axis of the supporting spindle of the guide roller intersects the centre of the
pass vertically at the same point and at right angles to the axis of the pass and
to the axis of the cylinders B, and C.
The point X, at which these axes intersect may therefore be considered as the
universal centre of the machine. I deem it desirable that the compressing roll,
the "pass" side of which revolves in the direction towards the guide roller, shall
slightly higher peripheral speed than the opposing roll in order that its
have a

page_text: tendency to bear the work down upon the guide roller may exceed the tendency of
the other roll to lift the work away from the guide roller.
In the drawings, the roll J, is the one which should have this greater peripheral
speed and it may be attained either by making the roll J, slightly larger in
diameter than the roll K, or by giving to it a slightly higher speed of revolution.
This insures the work being held in proper contact with the guide roller at all
times. Instead of the work being held down upon the guide roller by a
differential speed of the compressing rolls as just described this may be accom-
plished by locating the centre of the pass slightly below a line drawn through the
centres of the rolls. In such an event the axis of the pass would not be exactly at
the narrowest space between the two rolls and the work could not escape from the
true line of the pass because of its being wider than the narrowest space between
the rolls through which it would have to go.
In the drawings I have shown the compressing rolls as plain cylinders with
straight sides but in some cases it is desirable to make these sides more or less
convex, the convexity however not being very great, and I may use such a con-
struction of the rolls in the practice of my invention.
In Figures 10, 11, 12 and 13 I illustrate certain steps in my process of manu-
facturing tube having straight parallel sides and varying thicknesses with conse-
quent variation of the internal diameters of the finished product.
In Figures 10, 11 and 12 I show the production of a tube in which the ends are
made thicker and stronger than the central portions thereof. In the production
of such tube I use a mandrel like that iliustrated in the figures referred to, having
a central portion 7, the diameter of which is equal to the largest interior diameter
of the finished tube. The ends n, of the mandrel, are smaller than the central
portions, their diameters being equal to that of the smallest interior diameter of
the finished tube, these ends are united to the larger central portion of the
mandrel by tapering portions o.
The tube or blank W, to be drawn has preferably an interior diameter equal to
that of the central portions 1, of the mandrel and it should preferably be as thick
or thicker than the heaviest or thickest part of the finished tube. One end of the
tube as at w, is closed down so as to fit upon the small end of the mandrel and
pass freely through the opening of the drawing plate or die Z. This reduced end
of the tube and the mandrel within it are grasped by the tongs or grippers of the
draw bench when the tube is being drawn. As shown by Figure 12 of the draw-
ing, after the tube has been drawn through the die it closely embraces tho
mandrel within it, the ends of the tube surrounding the reduced portions of the
mandrel being thicker than its central portions which embrace the larger central
portions of the mandrel.
Under this condition of affairs it would be impossible to extract the mandrel
from the interior of the tube without some special process for releasing it as the
central portion of the mandrel is larger in diameter than the interior diameters
of the end of the tube. In order however to accomplish this extraction of the
mandrel, I subject the tube to a cross rolling process, in my mechanism herein-
before described, which diminishes its grip upon the mandrel at all points and
enlarges its ends sufficiently to permit of the mandrel to be extracted from it.
This cross rolling may leave the tube somewhat irregular in shape and slightly
varying in exterior diameters and in order to remove these irregularities and
reduce it to perfect finished form, I may again pass it through the die or draw-
plate for the purpose of giving it a sinking draw without the use of an interior
bulb or mandrel which reduces it to a uniform exterior diameter, the outsides
being straight and parallel and any variation in thickness being entirely upon
the inside of the tube.
In Figure 13 I illustrate in conjunction with another form of mandrel, a tube
thereon which may be produced by my process. In this case the tube is thicker
at its centre than it is at its ends and the mandrel may be divided into two
lengths at the line Y, of its smallest diameter to avoid the necessity for more

page_text: cross rolling than is necessary to relieve the mere frictional contact of the tube
on the mandrel. The ends of the mandrel sections may abut together at this
point or one section may be screwed into the other, as shown, or they may be
united in any other suitable manner.
The making of plain straight tubes r, of uniform interior and exterior diameters
upon plain straight mandrels M, such as are shown in Figures 1, 2 and 3 of the
drawing, will be so readily understood from the foregoing description as to need
no extended explanation.
I have described and illustrated rolls as forming the sides of a pass and as a
means for rolling and compressing the work in the pass but other well known
forms of moving or roll surfaces such as discs, and the like might be employed
with efficiency and more or less successful results and not evade the spirit or limits
of my invention as I may use any suitable moving surfaces at the opposed sides
of a pass in combination with the mandrel and its encasing tube as described.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The process of manufacturing or treating metal tubes, substantially as set
forth.
2. The process of manufacturing or treating seamless metal tubes which con-
sists in drawing and stretching the previously formed tubular metal lengthwise
in a cool or cold state upon a moving mandrel which is free to travel with the
metal, thereby producing a circumferential tension around the said mandrel and
securing the tube to it by friction, and thereafter stretching the metal circum-
ferentially and so enlarging it and loosening it upon the said mandrel by subjecting
it to lateral transverse rolling pressure against the said mandrel, substantially
as set forth.
3. In the process set forth in Claim 2, the reduction of the outer diameter and
slighter reduction of the inner diameter of the tube by drawing it down on to a
slightly smaller loose mandrel, and the subsequent increase of the internal diameter
by cross-rolling pressure that stretches the tube circumferentially and relieves
its grip upon the mandrel, without affecting the mandrel, substantially as set
forth.
4. In connection with the process set forth in Claims two and three the removal
of the mandrel and the further reduction of the external diameter by cold drawing
without the mandrel, whereby the tubular metal is first reduced in diameter on
to the mandrel, then expanded internally upon the mandrel, and thereafter reduced
externally without the mandrel.
5. The combination of pressure rolls mounted with their axes and working faces
all substantially parallel with the line of the pass, a loose mandrel free to travel
lengthwise and turn with the metal being treated, mechanism positively rotating
the said rolls and thereby rotating the mandrel and metal, substantially as set
forth.
6. The combination of pressure rolls mounted with their axes and working faces
all substantially parallel with the line of the pass, a loose mandrel free to travel
lengthwise and turn with the metal being treated, mechanism positively rotating
the said rolls and thereby rotating the mandrel and metal, and means for
angularly adjusting the said rolls to produce lengthwise progression of the work,
substantially as set forth.
7. The combination of compressing rolls upon opposite sides of a pass the axes
of which lie in planes substantially parallel to the axis of the pass and to each
other, a mandrel and tube located in the axis of the pass and revolved by the
action of the rolls which compress the walls of the tube against the mandrel and
expand its diameter, with means for adjusting the inclination of the axes of the
rolls relatively to each other and to the pass without changing said planes, and a
roller guide at one side of the pass the axis of which is substantially parallel to the

page_text: pass with means for inclining the axis of the roller guide without changing its
plane relatively to the pass, substantially as set forth.
8. The combination of compressing rolls upon opposite sides of a pass with
means for adjusting them laterally towards or away from each other and means
for adjusting the inclination of their axes relatively to each other and to the pass
without changing their relative planes, a roller guide located at one side of the
pass with means for moving it towards or away from the axis of the pass and means
for inclining its axis without changing its plane relatively to the pass as set forth.
9. The combination of compressing rolls on opposite sides of a pass the axes of
which lie in planes substantially parallel to the axis of the pass, the rolls being
movable towards or away from said axis with means for automatically forcing them.
together under yielding spring pressure, and an adjustable stop to limit their
movement in this direction substantially as set forth.
10. The combination of compressing rolls located at opposite sides of a pass
and carried by supporting frames, guide-ways in which said frames may move
at right angles to the pass the guide-ways being formed in structures rotatable
on an axis intersecting the axis of the pass at its mid-length substantially as set
forth.
11. The combination of compressing rolls located at opposite sides of a pass
and carried by supporting frames, guide-ways in which said frames may move
at right angles to the pass the guide-ways being formed in cylindrical structures,
a main frame having bearings at each side of the pass in which the said cylindrical
structures are mounted and may revolve on an axis at a right angle to the axis of
the pass substantially as set forth.
12. The combination of the main frame, the cylindrical structures mounted in
bearings therein on a common axial line and provided with longitudinal guide-
ways, frames which reciprocate in said guide-ways, compressing rolls carried by
said frames and located on opposite sides of a pass the axis of which is at right
angles to and intersects the axial line of the cylindrical structures, with means for
adjusting the rolls and their supporting frames towards or away from each other
substantially as set forth.
13. The combination of the cylindrical main frame with bearings in the same
axial line, cylindrical structures mounted and free to rotate in said bearings but
held against endwise movement therein, guide-ways in said structures, frames
mounted in said guide-ways and carrying rolls located at each side of a pass, the
axis of which is at a right angle to the axis of the cylindrical main frame, cross
bars or caps on the outer ends of the main frame with screws projecting through
them to adjust the rolls and their frames towards or away from each other sub-
stantially as set forth.
14. The combination of the cylindrical main frame, and the cylindrical struc-
tures mounted within it, the guides in said structures, the frames mounted in said
guides and carrying rolls located at opposite sides of a pass, a screw in one end of
the main frame bearing against the end of the adjacent roll frame, and a rod or
plunger at the other end of the main frame bearing against the other roll frame
with a yielding pressure, substantially as set forth.
15. The combination of the main frame, the rolls therein located at opposite sides
of a pass, the frames which carry the rolls mounted in guides so as to move to-
wards or away from the pass, one of said roll frames being adjustable but held in
rigid operative position, the other being also adjustable but yieldingly pressed
towards the pass with means to limit this movement substantially as set forth.
16. The combination of the main frame, the roll frames mounted in suitable
guides therein, means for adjusting and rigidly holding one of said frames in its
operative position, the plunger spring pressed against the other frame and the
adjusting screw through which it passes with a rigid collar on the plunger to con-
tact with the screw and limit its movement substantially as set forth.
17. The combination of the main frame, the roll frames mounted in suitablo
guides therein, one of said frames being rigidly held in operative position while

page_text: the other is urged towards it by a spring pressed plunger, the collar on the plunger,
and the spring bearing at one end against the collar with the hollow screw through
which the outer end of the plunger passes pressing upon and adjusting the
tension of the spring substantially as set forth.
18. The combination of the main frame, the compressing rolls carried thereby
and forming a pass between them, the roller-guide located below said pass and
mounted in bearings upon the head of a shaft or spindle the axis of which inter-.
sects the axis of the pass at its mid-length substantially as set forth.
19. The combination of the main frame, the compressing rolls carried thereby
and forming a pass between them, the roller guide located below the pass and
mounted in bearings upon the head of the shaft or spindle the axis of which inter-
sects the axis of the pass at its mid-length, a screw bearing against the lower end.
of the spindle to adjust and hold it at any desired elevation and a set-screw in the
bearing of the spindle to hold it against rotation, substantially as set forth.
Dated this 23rd day of December 1897.
For the Applicant,
J. G. LORRAIN, M. I. Mech. E., &c.,
Norfolk House, Victoria Embankment, London, W.C.,
Chartered Patent Agent.