Process of and Apparatus for Forming, Rolling and Finishing Tubes and other Hollow Metal Bodies
Year: 1891

page_text: Date of Application, 24th Feb., 1891
Complete Specification Left, 24th Nov., 1891-Accepted, 23rd Jan., 1892
PROVISIONAL SPECIFICATION.
Process of and Apparatus for Forming, Rolling and Finishing Tubes
and other Hollow Metal Bodies.
1, MAX MANNESMANN, of Komotau, in the Kingdom of Bohemia, Engineer, do
hereby declare the nature of this invention to be as follows;-
For
This invention relates to a method of and apparatus for imparting to tubes and
other hollow bodies any desired form in a rolling mill, that is to say, for bringing
them into definite sectional or longitudinal shapes, for finishing them or smootuing
them, and also when desired, for reuticing the thickness of the wails, and the internal
diameter. Such for instance as for producing hollow rails of certain configurations,
hollow columns or bearers with ribs &c., out of tubes of circular section.
this purpose according to this invention the tube to be treated is placed upon a
mandril and is so operated upon therewith between rolls that at each rolling
operation only a short length of the tube is worked, whereupon the tube and the
mandril receive a movement in the contrary direction, in order then to be again
moved forward in the original direction, so that the tube and, if necessary, also the
mandril are made to perform a step by step forward motion with intermediate
retrogression, and the tube is made to pass by degrees either entirely or only
partially through the rolls.
By this means the tube is not worked upon consecutively along its entire length
but only bit by bit, so that the point of operation progresses, as it were, from one
end of the tube to the other.
Thus, whereas in the ordinary process of drawing a tube, this is each time
meved entirely through a die, the size of the tube being reduced by passing it
consecutively through several drawing dies of decreasing size, according to the
present invention the tube receives its final shape by being passed a single time
through the rolls, between which it remains the whole time, performing a series of
comparatively short longitudinal movements.
If the end of the tube where the working commences be designated as the front
end, and the opposite end as the rear end, while the movement of the tube from
the rear towards the front end be called the forward motion and the reverse move-
ment the backward motion, then the working of the tube can take place either
only during the forward motion, or portion thereof, or only during the backward
motion, or a portion thereof, or the working may take place both during the forward
and the backward motion.
In some cases it is necessary after each action of the rolls to effect a partial
rotation of the tube round its longitudinal axis, in order that the rolls may operate
upon a different part of the tube.
If the inner surface of the tube or hollow body is to be cylindrical, the forward
motion of the mandril is made as great as its backward motion. The mandril itself
may in this case be either cylindrical prismatic conical, conoidal or of a composite
TD011

page_text: .
form according to whether the internal diameter of the tube is not to be materially
reduced, or is to be reduced, or the inner configuration generally modified.
If the conical or conoidal mandril be made at the same time to perform a step by
step forward motion, with intermediate retrogression, the inner diameter of the tube
or the inner configuration of the section of the hollow body can by this means be
made to vary in size at different points in the length of the tube or body. It is
advisable to insure that the longitudinal motions of the mandril and of the tube or
body shall be unequal, so that the latter shall be drawn or forced off the mandril
already during the rolling operation.
If the mandril has a stepped form imparted to it, the inner diameter of the tube
may also be reduced at certain places, by so moving the mandril that its smaller
part shall be situated between the rolls at the time when these are acting upon the
part in question of the tube. The same effect can also be produced if the mandril
be so moved that at certain times it is not at all situated between the rolls. In
either case consequently the mandril must receive, in addition to the reciprocating
motion, an advancing motion corresponding to the form of the steps thereof.
The rolls serving to carry out this operation may either receive a continuous
rotary motion in the same direction or they may have a to-and-from reciprocating
motion. Only in the latter case can the working of the tube be effected during
both its forward and backward motion.
In any case the rolls may have either concentric or eccentric or tapering calibers,
or both combined. If the rolls are only to be employed for calibrating that is not
for materially varying the sectional form, it is sufficient to give the working parts
thereof a concentric form with somewhat rounded edges.
For the sake of simplicity two rolls having parallel axes will generally be
employed but the process may also be carried out with three or more rolls forming
a calibre between them and whose axes lying in the same plane, would in that case
form angles of 60 degrees or 90 degrees with each other.
When there are four rolls in one and the same plane, they may either all operate
simultaneously, or one pair may operate forwards and the other pair backwards.
With a single pair of rolls these may be arranged either vertically one above the
other, or side by side with the axes horizontal or vertical or otherwise arranged.
Also like in universal rolling mills, two or more pairs or groups of rolls may be
used, arranged one behind the other, and which either act simultaneously or con-
secutively upon the metal object, in which latter case, both sets of rolls may work
the metal in the same direction, or the one set may work it in the one direction and
the other in the opposite direction.
If the one pair of rolls have their axes horizontal, while those of the other pair
are vertical, the metal object need not be turned during the operation.
The calibres may be made to run in a helical line or the calibres being of them-
selves straight, may be arranged side by side with their commencements lying on a
helical line. The separate calibres may be formed with steps, or the following
calibres can be widened or narrowed.
In order to enable the shifting or turning of the metal object to be effected freely
during the period when no action thereon is being effected by the rolls, they are
formed with corresponding gaps or flat faces, unless they are moved apart for
liberating the rolls.
In a similar manner to that in which the interior of the tube or hollow body can
be made to vary during the rolling process by shifting the mandril, the outer
configuration thereof can also be made to vary at different parts of the length by
either varying the above described step-by-step forward motion with retrogression
of the object, or by periodically moving the rolls to or from each other, or by
varying the rotation thereof during the rolling. By this means consequently it is
for example, possible to roll hollow objects having equal strength throughout to
resist transverse strain, such as connecting rods, beams, columns, &c.
The operation can also be interrupted at intervals that is, after operating on a

page_text: certain length of the object, if it is intended to produce this with an externally
stepped form.
The movement of the object operated on can either be effected by means of the
rolls acting thereon, or by special mechanical means.
Thus when using two pairs of rolls, the first pair can be made to effect the
forward motion and the second pair the backward motion, and the combined step-
by-step forward and retrogressive motion may be effected by causing the first
named motion to be somewhat greater than the second motion, so that the metal
object will advance by degrees.
If the axes of the rolls be placed somewhat obliquely relatively to each other or
to the longitudinal axis of the object, the latter will be automatically rotated or
partially rotated by the rolling operation, and it will then be sufficient to move back
the object by a second pair of rolls during the period when the first pair is not
operating thereon, without imparting any rotation to the object. Consequently.
with the use of two sets of rolls arranged one behind the other working in contrary
directions, the step by step forward and intermediate retrograde motion of the metal
object, as also its rotation, may be entirely effected by the action of the rolls them-
selves. Generally speaking the necessary movement of the metal object will be
determined by the special description of rolling process which it has to undergo or
by the nature of the metal object itself.
I will proceed to describe various arrangements for rolling tubes and hollow
bodies according to this invention with reference to the accompanying diagram
drawings, leaving out of consideration the means for driving the rolls and for
actuating the mandril and the object to be operated upon.
Figs. 1 to 8 show the rolling of a tube upon a cylindrical mandril by means of
rolls which revolve continuously in the same direction and it is assumed that the
action of the rolls upon the tube is effected during the forward motion thereof, the
rolls being provided with excentric or tapering calibres.
The rolls A and B which are suitably supported and driven revolve continuously
in the direction of the arrows 1 and 2, and have in addition to the calibres which
are shown by way of example more particularly in Figs. 12, 13 and 14; gaps or flat.
places a, which allow of the retrograde motion of the metal object W when it
has to be brought back into a new commencing position for the attack of the
rolls. Fig. shows by way of example such a commencing position. The
tube W carried upon the mandril D has been approached towards the rolls A and 13
to such an extent (forward motion) that its front end is seized by the rolls and is
acted upon thereby in the manner indicated by Fig. 2. During such action the
mandril 1 preferably (but not necessarily) has a less forward motion imparted to
it than the tube W (this being indicated in Fig. 1 by the unequal lengths of the
two arrows 3 and 4). By the said rolling the front end of the tube will be
elongated in a manner corresponding to the calibre of the rolls A and B until the
gaps a of the rolls commence to come opposite to each other as at Fig. 2. The
attack of the rolls ceases at this moment and the tube W together with
the mandril D can now be moved backward in the direction of the arrow 5
(backward motion) as the tube is now entirely freed by the rolls. During such
backward motion, rotation of the tube together with the mandril is effected round
its longitudinal axis in the direction of the arrow 6, so that at the next attack of
the rolls other parts of the cross section come under operation. The extent of
the gaps a of the rolls has to be so made in proportion to the backward motion
of the tube that the latter will not be interfered with by the rotation of the
rolls. As furthermore the tube moves freely through the rolls during the
backward motion it follows that it must be suitably guided and supported in
the direction of its longitudinal axis as will be hereinafter explained. After the
completion of the backward motion of the tube Fig. 3 a fresh attack of the rolls
can take place by means of which a further elongation of the tube will be effected
as indicated at Fig. 4, until by the rotation of the rolls the gaps a are again
presented opposite each other. During the further rotation of the rolls A and 13

page_text: the tube can be moved backward in the direction of the arrow 5 as described
with reference to Fig. 2 and at the same time be turned round its longitudinal axis
in the direction of the arrow 6 so as to be brought into a suitable position for the
next attack of the rolls.
As will be seen from a comparison of Figs. 1 and 3 the tube will be seized at
each fresh attack of the rolls by a narrower portion of the calibre thereof. If the
rolling operation has procceded so far that the rolls can act upon the tube with the
narrowest part of their calibre no further reduction of the cross section of that part
of the tube can take place, so that on the following rolling of the thicker part of
the tube situated behind such part the outer diameter can be no further reduced at
that point, so that the front end of the tube will become cylindrical as shown at
Fig. 4. The following backward motion of the tube consequently has to be so
proportioned that the tube is only moved back so far that the conical part thereof
will be seized by the rolls at the next attack, while the cylindrical end of the tube
will remain behind the rolls as indicated at Figs. 5 and 6. From this point forward
the cylindrical part of the tube will increase in length at each attack of the rolls.
and as the forward motion of the tube is always greater than that of the mandril as
above stated, it follows that the tube W will be gradually drawn away over the
mandril by the rolls. If the forward and backward motions of the tube in the
direction of the arrows 3 and 5 be drawn out in a broken line as at Fig. 7 it will be
seen that the tube must be moved forward during the rolling operation with a step
by step forward and intermediate retrograde motion. The small circular arrows in
this figure show at the same time the attack of the rolls during the forward motion
of the tube in the direction of the arrow . For effecting the relative shifting of
the mandril and tube it is quite sufficient if the mandril be moved forward during
the forward motion of the tube only to such an extent as it was previously moved
backward, so that the extent of the forward motion in the direction of the arrow 4
will be equal to the backward motion in the direction of the arrow Fig. 5. To the
tapering or excentric part of the roll calibre there is by preference added, as
assumed in all the figures, a concentric part so that in this part of the calibre, a
smoothing of the rolled part of the tube will be effected, so that the tube will
eventually leave the rolls in a smooth condition; as at Fig. S.
Instead of causing the rolls to attack the tube during the forward motion this
may be effected during the backward motion. Fig. 9 shows by way of example the
termination of such an attack where the concentric part of the calibre is already in
action. The rolls A and B revolve in the direction of the arrows 7 and 8 and the
backward motion of the tube in the direction of the arrow 9 is less than that of the
mandril in the direction of the arrow 10. When the gaps a of the rolls face each
other as at Fig. 10 the tube together with the mandril can be again freely moved
forward in the direction of the arrow 11, so that a further portion of the tube is
presented to the renewed attack of the rolls. In this case also the forward motion
will be greater than the backward motion, so that the step by step forward and
intermediate retrograde motion shown in Fig. 11 will take place, but whereas in the
former case the attack of the rolls commences at the smallest diameter of the tube,
in the present case the rolling operation will commence at the larger diameter
thereof. There results consequently at the attack of the rolls during the forward
motion Fig. 7a rolling operation from the thinner end of the tube towards the
thicker part, whereas when the rolls attack the tube during the backward motion
as at Fig. 11 the rolling operation will take place from the thicker end of the tube
towards the thinner end as will be readily seen. The backward motion of the
mandril is preferably made equal to the forward motion of the tube, so that during
the rolling process the tube will be pushed along over the mandril. The calibre
of the rolls will of course depend upon the desired section of the tube to be obtained.
With circular calibres as at Fig. 12 one portion thereof is made oval, while the
concentric part thereof serving to smooth the tube is made up of two semicircles.
If the cross section of the tube is not circular but polygonal the eccentric portions
of the calibre can be similarly formed as indicated at Fig. 14, for a rectangular

page_text: cross section, or the desired configuration of the cross section may be imparted only
to the concentric part of the calibre serving to smooth the tube while the eccen-
tric part of the calibre is made circular or oval as at Fig. 13. Both parts of the
calibre in that case gradually die away into each other. If the cross section of the
tube after rolling is not circular the angle through which it is turned after each
attack of the rolls cannot be made optional, but must be in correspondence with
the form of the section so that for example, with a square section the tube must
always he turned 90 degrees with a hexagonal section 60 degrees or 120 degrees.
If the cross section is not a regular polygon the rolls are made with several
working sections and a corresponding number of gaps. Figs. 15 to 18 show
rolls of this description in cross section and front view the calibres being formed
for the profiles shown at Figs. 19 and 20. The two calibres k of the rolls A and B
are relatively so formed that the profiles 19 and 20 are rolled thereby in the
indicated position.
If the rolls have revolved to such an extent that the gaps thereof are presented
to each other the backward motion of the tube and a rotation thereof round its
longitudinal axis through 90 degrees is effected. The tube is now seized by the
calibre which corresponds to the profiles 19 and 20 when turned through
90 degrees as shown dotted at the upper sides of the rolls Figs. 16 and IS.
During the backward motion of the tube when the gaps of the rolls are
presented to each other the tube must be again turned back through 90 degrees
for the section shown at Fig. 19, whereas for the section shown at Fig. 20 the
tube can be turned 90 degrees forward again.
If the rolls A and B Figs. 15 and 16 were provided with four calibres instead
of only two, which would correspond to the consecutive positions of the profile
Fig. 1 when turned through 90 degrees this profile could also be turned forward
90 degrees during the backward motion instead of being turned backward. Such
rolls with several operating sections and gaps may also be usefully employed when
rolling cylindrical objects.
As with the above described rolling process it is very desirable to have a
perfectly reliable seizure of the rolls it is advisable under certain circumstances
to form the operating portions of the rolls with serrated or stepped projections i
as shown at Fig. 21 by means of which projections the tube will be gripped with
increased friction and be thus drawn through the rolls with certainty.
The above described process is capable of various modifications according to the
purposes to which it is to be applied some of which have already been indicated.
As the rolls only operate on the tube during a portion of their rotation it follows
that it is in no way necessary to cause them to perform complete revolutions but
that they may also have a to and fro motion imparted to them. Also in this case.
as above described the rolls may be made to operate either only during the forward
motion or only during the backward motion of the tube. Such a rolling mill with
to and fro motion of the rolls may however also be so arranged that the rolls
operate both during the forward and the backward motion of the tube, whereby a
considerably more rapid mode of working is rendered possible. This mode of
working is indicated by Figs. 22 to 29. The rolling process at the commence-
ment of the operation with the rolls in the position shown at Fig. 22 correspond
exactly with that described with reference to Fig. 1. The rolls A and B rotating
in the direction of the arrows 1 and 2, seize the tube. W which moves forward in
the direction of the arrow 3, while the mandril D also moves forward, but at a
slower rate, this being again indicated by the unequal lengths of the arrows 3 and 4
As soon as the rolling operation has been completed and the gaps a face the
tube W as at Fig. 23, the rolls remain stationary, and the tube together with the
mandril, are moved forward in the direction of the arrow 12, while they are at
the same time partially rotated round their longitudinal axes in the direction of the
arrow 6, the forward motion being to such an extent that they arrive in the
dotted position, so that the rolls A and B at their following backward motion in
the direction of the arrows and S. at once seize the tube at the thicker part and

page_text: move it backward in the direction of the arrow 13, while the mandril is moved
in the same direction as indicated by the arrows, but with a greater speed. Con-
sequently whereas in the former case the rolls operated from the thinner towards
the thicker part of the tube they now operate in the contrary direction until
they have arrived in the position Fig. 24, in which the action of the rolls on the
tube ceases and the gaps a of the rolls permit of a forward motion of the tube
together with the mandril in the direction of the arrow 15, these parts being at
the same time rotated as indicated in dotted lines at Fig. 24. In this position
the tube W is ready for a fresh attack of the rolls A and B when the latter again
rotate.in the direction of the arrows 1 and 2. The tube will then be again moved
forward in the direction of the arrow and the mandril will also move in the
same direction but with less speed, as indicated by the arrow 4, so that towards
the end of this period, the position shown at Fig. 25 will be reached in which
avain a small forward motion of the tube and mandril in the direction of the
arrow 12 together with rotation in the direction of arrow 6 can be effected until
the tube is brought into the position for being attacked by the rolls during their
rotation in the direction of arrows 7 and 8. In this way the rolling operation is
further carried on as indicated in various phases at Figs. 20 27 and 28 and which
require no further description.
If the movements performed by the tube during its passage through the rolls be
drawn out in a broken line, as at Fig. 29, it will be seen that the tube again
performs a step by step forward and intermediate retrograde motion. For the
sake of clearness the several parts of the forward and backward motion in this
figure are shown drawn asunder but in reality. the shiftings 15, and 12 will
follow each other closely if they are brought in proper relation to the reversed
motion of the rolls. The step by step forward and intermediate retrograde motion
will therefore in this case only differ from that of Fig. 7 in that the forward
motion of the tube at two following attacks of the rolls will be increased by the
shiftings 12 and 15, which results as already remarked in a considerably quicker
mode of working. The mandril moves forward in the direction of the arrows 4,
12 and 15 and backward in the direction of the arrow 14. The latter motion
has therefore to be made equal to the sum of the two first if the mandril is
required to occupy the same position at the end of the rolling operation as it did
at the commencement thereof and the tube will at each attack of the rolls then
be drawn forward over the mandril. The rolls in this case need not necessarily
be formed as complete cylinders at the points beyond the calibres Fig. 12, but
it is quite sufficient if they are formed segmental, that is to say the cylinders
being only formed to such an extent as to cause them to roll upon each other
during the backward motion. Although such structures may not strictly
speaking, be called-rolls I will retain this designation as the working of the
tubes is effected by a rolling operation notwithstanding the said shape of the rolls.
In a similar manner to the ordinary rolling mills, the rolls employed for the
purposes of this invention may have several calibres formed side by side thereón
in which the metal is operated on either simultaneously or consecutively. With
this arrangement it is of advantage to place the operating portion (Fig. 15) of
the one calibre next to the gap or next position a (Fig. 15) of the contiguous
calibre, so that a tube is being operated upon in the one calibre while in the next.
calibre the gaps allow of the free motion of the tube.
Instead of rolls with tapering and concentric calibres with gaps.there may also
be employed rolls with concentric calibres without gaps if in this case at each
attack of the rolls these are made to approach each other or to move away from
each other. This mode of operating is more particularly advantageous when
larger metal objects are to be operated upon. The movement of the rolls may
he advantageously effected by means of hydraulic cylinders with pistons which
carry, the bearings of the lower rolls as shown at Figs. 30 to 34 for rolls with
to and fro motions. If the rolls A and B operate during the forward motion of
the tube W in the direction of the arrow 3 Fig. 30 the lower roll is made to sink

page_text: down gradually in the direction of the arrow 16, the piston F of each lower
bearing being made to sink down in its cylinder to a corresponding extent. The
reverse motion in the direction of the arrow 17, Fig. 31 is effected by the pistons F
during the attack of the rolls when the tube is being moved backwards in
the direction of the arrow 13. Fig. 32 to 34 show the further advance and the
termination of the rolling operation. With this process the rolls are made with
oval calibres, and after each attack a partial rotation of the tube together
with the mandril round its longitudinal axis is necessary, for which purpose
the rolls have to be moved so far apart that they allow of the free shifting and
rotation of the tube.
The required greater distance apart of the rolls at the commencement of the
rolling process may be effected by the adjustment of the upper roll bearings in
the known manner by means of screw spindles and toothed gearing.
The movement of the pistons is effected by the admission of fluid pressure
from an accumulator into the cylinder G but the shifting of the position of the
roll may be effected by a mechanical device such as by a lever actuated by an
eccentric or by means of wedge gearing as shown at Fig. 35, where the wedges I
of both bearings are moved to and fro, which will have the well understood action
of raising and lowering the lower roll. The upper roll may also be mounted
in movable bearings in the same manner as the lower roll and be raised and
lowered during the rolling operation or both rolls can be raised and lowered
simultaneously.
In all the cases above referred to there may he employed in place of the cylindrical
or prismatic mandril a conical or conoidal one, but in order that the hollow metal
object may be shaped cylindrical or prismatic it is necessary that the backward
motion be made equal to the forward motion in order that always the same
part of the mandril shall assume the same position relatively to the central plane
through the axes of the rolls, this not being essentially necessary with cylindrical
mandrils although it is preferred for the moving mechanism of the mandril.
Fig. 36 to 43 show the rolling operation with such a conical mandril, the outer
configuration of the metal object being at the same time also conical. The
rolls A and B are in this case provided with two working sections and two
gaps. The working sections have tapering or eccentric calibres and the rolls
revolve continuously in the direction of the arrows and 2. In Fig. 36 the first
attack takes place. After the completion thereof, as at Fig. 87, the backward
motion of the metal object together with the mandril, and the rotation of the whole
round the longitudinal axis takes place as described with reference to Fig. 2. The
five following figures show various further stages of the rolling operations while in
Fig. 43 the rolling is supposed to be completed.
For producing the outer conical configuration of the metal object the rolls are
moved slightly apart after each attack, which may be effected for instance by the
rotation of the screw spindles for the adjustment of the bearings of the upper roll.
This movement of the screw spindles or of their driving gear may he readily
effected by a ratchet mechanism which is actuated by one of the rolls or in any
other desired manner. If the ratchet mechanism be moved to the same extent
for each rotation of the rolls, the outer configuration of the metal object will be
conical or with polygonal cross section in the form of the frustrum of a pyramid
If on the other hand the extent of motion of the ratchet gear be varied for
cach rotation the metal object will become conoidal or of curved form.
during the rolling operation the rolls be made to approach each other, the rear
end of the metal object will be thinner than the front end thereof.
If
Fig. 44 shows how by first moving the rolls away from each other and then
causing them to approach hollow bodies of cylindrical or prismatic hollows can be
produced which have in the middle thicker walls than at the ends such for
example, as is required for objects having equal strength throughout their length.
There is no difficulty in effecting, by means of suitable actuation of the ratchet
gear for the adjusting spindles of the rolls, any desired variation in the cross

page_text: section with reference to the longitudinal axis of the body. The same process
may also be employed in combination with rolls having to and fro motion, but
in this case the same results may be obtained by varying the backward motion as by
the adjustment of the rolls, or such action may be used in combination with the said
adjustment. This will be readily seen if it be considered that the outer diameter or
outer configuration of the metal object will be determined by the end position of the
rolls at Fig. 28.
.'
If the reversing motion of the rolls be modified in such a manner that in place of
the narrower portions of the calibres by degrees the larger portions operate upon
the metal object towards the end of the separate attacks, a gradually increased
diameter in the longitudinal direction of the metal object will result. In a similar
manner a decrease of the diameter may be effected if by degrees smaller portions of
the calibre be made to act upon the metal object at the end of each rolling operation.
The conical or conoidal mandril also allows of a variation of the cross section of
the hollow of the metal object in the longitudinal direction if the motion of the
mandril be so arranged that thicker or thinner parts thereof be made to lie in the
central plane of the rolls at the end of each rolling operation.
Fig. 45 to 52 show the mode of producing a tube of cylindrical outer form and
with a conical hollow in the above described manner. The several figures again.
represent generally the before described Figs. 36 to 43; but as will be seen from a
comparison of the Figs. 45, 47, 49, 51 and 52 the point of the mandril recedes
gradually from the central plane of the rolls in such a manner that towards the end
of each rolling operation a thicker part of the mandrel is situated in this plane.
Such movement of the mandril is effected when a step by step forward and inter-
mediate retrograde motion is imparted to it similar to that of the metal object as
described with reference to Fig. 7. If this motion he so arranged that by degrees.
thinner parts of the mandril are situated in the central plane of the rolls at the end
of each rolling operation the hollow will become gradually narrower instead of
Jarger as shown at Fig. 52. Fig. 53 shows how by the combination of both step by
step forward and intermediate retrograde motion, bodies can be produced which
have external cylindrical or prismatic configurations, while internally they have
thicker walls at the centre than at the ends so as again to afford equal strength in
the direction of the length. If, lastly, as indicated in Figs. 54 to 61, the rolls are
also made to move away from each other gradually during the step by step motion
of the mandril the outer surface of the body will also become conical or pyramidal.
The positions of the rolls, the metal object and the mandril correspond to those at
Figs. 45 to 52 and after what has been stated, they require no further description.
In this case both motions can be so arranged that the thickness of the walls is
equal in all parts of the longitudinal axis. or the thickness of the walls may be
varied. In this way there may also be obtained, by suitable alteration of the
position of the rolls or step by step motion, bodies of the form shown at Fig. 62.
The cross section of the mandril need not necessarily be similar to the outer
configuration of the metal object.
In manufacturing the tubes or hollow bodies with inner ribs the mandril will,
as shown by way of example at Fig. 63, have to receive corresponding recesses t
at its front end, into which the metal is pressed by the rolls during the operation.
If the tube is to have external ribs the calibre of the rolls must be made in a
corresponding manner.
As ahove stated, under certain circumstances the guiding and movement of the
metal object and mandril will be required during the rolling operation. A
portion of this guiding and movement can be effected by the rolls A and B them-
.selves, but both the mandril and the tube can also be moved and guided at both ends
Figs. 64 to 66 show a rolling mill with moving mechanism of the first description
by way of example, Fig. 64 being a longitudinal section Fig. 65 a plan and Fig. 66
a vertical section on lines y y Fig. 64. Figs. 67 to 74 show detached details of the
mechanism. The lower roll B is driven by means of the shaft and drives the
upper roll by means of toothed gear e and d, while by means of toothed gears f, g,

page_text: and it drives the cam shaft k. On this shaft is a cam 1, which actuates the
lever n, rocking on the pivot m by means of the roller r.
The lever n is con-
P
tinuously pressed against the periphery of the cam by a spring q, being guided by
a forked piece p which embraces the lever n at the axis of the roller rand which has
a pivot 1. The free end of the lever moves the slide u to and fro which slides
in the cylindrically bored guide. On the central pivot ul of this slide is rotatably
mounted the socket v, with which the mandril D is connected. The socket v
Figs. 68, 69 and 70 is stepped and contains a rotatable ratchet ring w. Figs. 70 to 73
which is provided with a sloping projection 1 and with a pawl w 2, which gears
with ratchet teeth 1 of socket Fig. 70. The projection of the ratchet ring w
takes into a helical groove 1 of the guide t, Fig. 14 so that the ratchet ring w will
be moved to and fro in the guide t, during the to and fro motion of the slide u.
During the forward motion the pawl w 2 of the ratchet ring we will slide loose over
the teeth 1 of the socket v, whereas during the backward motion the socket will
be carried along by the ring w such motion of the ring and consequently also of
the mandril D being effected through an angle of 90 degrees..
The metal object to be operated upon, placed upon the mandril 1) is now carried
forward by the rolls A and B, while the motion of the mandril D which is deter-
mined by the cam will be somewhat less, so that, as before described, the metal
object will be simultaneously drawn off from the mandril during the rolling opera-
tion. On the backward motion of the mandril it carries the tube backward with
it by friction, while at the same time the rotation of the mandril and tube through,
an angle of 90 degrees is effected. The step by step motion of the tube is conse-
quently in this case effected by the action of the rolls themselves upon it. A's
the rolls A and B have two working sections the shaft k makes two revolutions
while the shaft b makes one. Of course k might revolve at the same speed as b
if the cam were made double.
1
In order to place the tube upon the mandril the slide s is moved back by means
of the elbow lever M and link as shown at Fig. 67, so that the spring allows the
slide to be moved so far back that the mandril D can be turned upwards upon the
pivot through the slot 2 of the guide . If it is desired with this arrangement
to impart to the mandril a step by step forward motion with intermediate retrogres-
Thus
sion, this may be effected by gradually shifting the pivot m of the lever a.
for example as shewn in the drawing the pivot m of the lever n may be mounted on
a slide P which can be shifted in the direction of the mandril D by means of a
screw S. This shifting may be effected either by hand or automatically by means
of a ratchet motion in any known manner, for example in a similar manner in which
the slide rest of a turning lathe is shifted. Fig. 75 shows another shifting arrange-
ment actuated by means of the piston of a hydraulic cylinder, the two ends of
which are made to communicate with an accumulator by means of pipes having
closing and opening devices, so connected that, according as may be required
fluid pressure can be admitted to the one or to the other side of the piston.
Fig. 76 shows a rolling mill of the second above described arrangement in which
the mandril and tube are moved and guided at both ends, such motion being
effected by means of differential levers, that is to say levers of unequal length.
The tube W is connected at its front end to a boss a 2 which may either be forged
in one piece therewith or which is preferably formed similar to gripping tongs, co
as to enable it to be fixed on the front end of the tube after it has been introduced
between the rolls. The trunnion 62 of the boss can rotate in the swivel joint d2
so that the rotation of the tube can be effected without requiring the swivel d2
to partake of such motion. With the swivel d2 is connected a rod f2 provided
with ratchet teeth which passes through a slot in the lever h 2 and is carried along
by the latter in the direction of the arrow by means of a ratchet pawl 92. The
lever 2 turns on a pivot k2 and receives a to and fro motion by means of the
crank pin i2 of the disc 12. This motion is transmitted by a rod m2 to a second
lever p2 which is situated on the other side of the rolling mill and is pivoted at q 2
and which has to impart the requisite motion to the mandril D. The latter is for

page_text: this purpose connected by a sleeve o2 in a rotatable manner, to the lever p2. The
point of connection of the rod m 2 to the lever h2 can be adjusted by means of a
screw 2 so that it is possible, according to requirements, to alter the proportion
between the motion of the mandril and that of the tube. The crank disc 12
receives, with the arrangement shown in which there is only one working section
on each roll, the same number of revolutions as the rolls A and B and it is so
arranged that it causes the levers 2 and 2 to perform a movement to the left as
soon as the gap a of the rolls A and B sets free the tube W. The rotation of the
latter can be effected either by means of the hand wheel s2 attached to the mandril D),
or a mechanism similar to that described with reference to Figs. 64 to 66 can be
used. The connection of the toothed rod 2 with the lever by means of the
pawl 2 renders it possible for the tube to be moved forward by the action of the
rolls A and B without causing the lever h2 actuated by crank disc 12 to partake of
this motion. Consequently, in rolling the tube the mandril D will always perform
the same to and fro motion, while the tube will be moved farther forward by ineans of
the rolls and will be moved backward in proportion to the length of the levers, thus
carrying out the before described step by step forward motion with intermediate
retrogression. It will be seen that during the working period, that is to say, during
the time when the rolls operate on the tube, an automatic drawing off of the tube
from the mandril will be effected by the retarded motion of the latter. If the
lengths of the levers be so taken that at the backward motion the mandril D moves
quicker to the left than the rod f2 there will also take place a loosening between
the mandril and the tube during the backward motion of the latter. If a drawing
off of the tube from the mandril is only to be effected during the working period
the spring might be employed as shewn in dotted lines which during the rolling
period is put in tension and in consequence of the different leverage during the
attack of the rolls effects a corresponding retardation of the mandril movement.
The backward motion of the lever p2 is then effected by the strained spring to
and will have to be limited by a stop 2 also shown in dotted lines. In this case
the spring 12 can also act directly upon the mandril. The mandril and the tube
consequently move with the same speed during the backward motion when a spring
is used. The removal of the tube from the mandril can also be made to take place
only during the backward motion, that is to say during that part of the operation
in which there is no rolling action exerted on the tube, but in this case a spring
will generally not be sufficient, and a positive motion will require to be imparted
to the mandril and tube, the mandril being made to move back quicker than the
tube. The required differential motion of the mandril and the tube may also be
effected by means of toothed gearing of different sizes instead of by levers of
different lengths. From the above it will be seen that the mechanism for the
movement and guiding of the tube may be effected in various other ways. It will
as a rule be arranged according to the nature of the metal object operated upon,
and the described arrangements are therefore only intended as examples for
carrying out the process.
Dated this 24th day of February 1891
Process of and Apparatus for Forming, Rolling and Finishing Tubes
and other Hollow Metal Bodies.
I, MAX MANNESMANN, of Komotau, in the Kingdom of Bohemia, Engineer, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to a method of and apparatus for imparting to tubes and
1

page_text: other hollow bodies any desired form in a rolling mill, that is to say, for bringing
them-into-definite-sectional or longitudinal shapes, for finishing them-or-smoothing
them,-and-also-when desired for reducing the thickness of the walls and-the-internal
diameter. Such for instance as for-producing-hollow-rails of certain configurations,
hollow-columns-or-bearers-with-ribs-ete, out-of-tubes-of-eirenler-section. For this
purpose according to this invention the tube to be treated is placed upon a mandril
and is so operated upon therewith between rolls that at each rolling operation only a
short length of the tube is worked, whereupon the tube and the mandril receive a
movement in the contrary direction, in order then to be again moved forward in the
original direction, so that the tube and, if necessary, also the mandril are made to
perform a step by step forward motion with intermediate retrogression, and the tube
is made to pass by degrees either entirely or only partially through the rolls.
By this means the tube is not worked upon consecutively along its entire length,
but only bit by bit, so that the point of operation progresses, as it were, from one
end of the tube to the other.
•
Thus, whereas in the ordinary process of drawing a tube, this is each time moved
entirely through a die, the size of the tube being reduced by passing it consecutively
through several drawing dies of decreasing size, according to the present invention
the tube receives its final shape by being passed a single time through the rolls,
between which it remains the whole time, performing a series of comparatively
short longitudinal movements.
If the end of the tube where the working commences be designated as the front
end, and the opposite end as the rear end, while the movement of the tube from the
rear towards the front end be called the forward motion and the reverse movement
the backward motion, then the working of the tube enn takes place either-only-during
the-forward-motion, or portion-thereof, or only during the backward motion, or a
portion thereof, or the working-may-take--place--both-during the forward-and-the
backward-motion.
In some cases it is necessary after each action of the rolls to effect a partial rotation
of the tube, round its longitudinal axis, in order that the rolls may operate upon a
different part of the tube.
If-the-inner-surface of the tube or hollow-body is-to-be-eylindrient, the forward
motion of the mandril is made as great as its backward-motion. The mandril-itself
may-in-this-ease-be-either-erlindrical, prismatic, conient,-conoidal, or-of-n-composite
form, necording-to-whether-the-internal-diameter-of-the-tube-is-not-to-be-materially
reduced, or is to be reduced,-or-the-inner configuration-generally-modified.
If the content or conoidal-mandril be-made-ut-the-same-time-to-perform-a-step-by
step forward motion, with-intermediate-retrogression, the inner diameter-of-the-tube
or-the-inner-configuration-of-the--section of the hollow-body can-by-this-means-be
made-to-vary-in-size-at-different-points-in-the-length-of-the-tube-or-body.-It-is
advisable-to-insure that the longitudinal-motions-of the-mundril-and-of the-tube-or
body-shall be-unequal,-so-that-the-latter shall-be-drawn-or-forced-off the mandril
already-during-the-rolling-operation.
If the mandril-has-a-stepped-form-imparted-to-it-the inner diameter of the tube
may-also-be-reduced-nt certain places, by so moving the mandril that its smaller
part-shall be-situated between-the-rolls-at-the-time when these-are--neting upon
the-part-in-question-of-the-tube: The-same-effect-ean also be produced if the
mandril-be-so-moved that at certain times-it-is-not-at-all-situated between-the-rolls:
In either-ense-consequently the mandril must receive, in addition to the reciprocating
motion;-an-advancing-motion-eorresponding-to-the-form of the steps thereof.
The rolls serving to carry out this operation may either receive a continuous rotary
motion in the same direction or they may have a to-and fro reciprocating motion.
Only in the latter case can the working of the tube-be-effected during-both its
forward-and-its-backward-motion.
In-an-ease The rolls may have either-concentric-or-eccentric or tapering grooves
in part concentric and. in part eccentric or tapering er-calibers, or both-speli
forms-combined. If the rolls-are-only to be employed for calibrating that is, not for

page_text: materially-varying the sectional form, it is sufficient-to-give-the working parts
thereof-a-concentric-form-with-somewhat-rounded-edges.
For the sake of simplicity Two rolls having parallel axes are will-generally-be
employed but-the-process-may-also-be-earried out-with-three-or-more-rolls forming a
calibre between them;-and whose axes-lying more-or-less-in-the-same-plane, would-in
that-ense-farm-angles-of-60-degrees-or-00-degrees with each other.
When-there-are-four-rolls-in-one-and-the-same-plane, they may either-all-operate
simultaneously, or-one-pair-mar-operate forwards and the other--pair-backwards.
With a single-pair of rolls these may-be-arranged either-vertically one-above
the other, or--side-by-side--with-the--axes--horizontal--or--vertical, or--otherwise
Arranged.
Also like in-universal rolling mills, two or more pairs or groups of rolls may be used,
arranged-one-behind-the-other, and which-either-net-simultaneously or consecutively
upon-the-metal-object, in which-latter-ense, both-sets-of-rolls-may work the metal in
the-same-direction;-or-the-one-set-may-work-it-in-the-one-direction-and-the-other-in
the-opposite-direction.
If-the-one-pair of rolls-have-their axes horizontal, while those of the other pair-are
vertien!, the-metal-object need not-be-turned-during-the-operation.
The-enlibres-or-grooves-may-be-made-to-run-in-helient-lines-round-the-rolls-or the
enfibres-being-in-circular-lines-may be arranged with their points of commencement
lying inn helical-line. The separate enlibres may be formed with steps, or the following
enlibres-may-be-widened-or-narrowed.
In order to enable the shifting or turning of the metal object to be effected
freely during the period when no action thereon is being effected by the rolls,
they are formed with corresponding gaps or flat faces, unless-they-are-moved-apart-for
liberating-the-rolls.
In a similar manner to that in which the interior of the tube-or-hollow-body-can-be
made-to-vary-during-the-rolling process by shifting the mandril, the outer configura-
tion-thereof enn also be made to vary at-different parts of the length by either varying
the-above described-step-by-step-forward-motion-with retrogression-of-the-object, or
y-periodically-moving-the-rolls-to-or-from each other, or by varying the rotation
thereof-during-the-rolling. By-this-means-consequently-it-is-for-example-possible
to roll-hollow-objects having-equal-strength throughout-to-resist transverse-strain,
sneh-as-conneering-rods, beams;-columns-fe
The operation-can-also-be-interrupted at intervals, that is, after operating on a
eertain length of the object, if it is intended to produce this with an externally
stepped-form.
The-movement-of-the-object-operated-on-enn-either-be-effected-by-means-of the
Thus-when-using-two pairs-of-rolls, the first pair-ean-be-made to effect the forward
motion-and-the-second-pair-the-backward motion, and the combined step-by-step
forward-and-retrogressive-motion-may-be-effected by causing the first-named motion
to-be-somewhat greater than the second motion, so that the metal object will advance
by-degrees.
rels-neting-thereon,-or-by-special-mechanical-means.
If the axes of the rolls be-placed-somewhat-obliquely-relatively to each other-or-to
the longitudinal axis of the object, the latter will be automatically rotated or partially
rotated-by-the-rolling operation, and it will then be sufficient to move-back the
object-by-a-second-pair-of-rolls during-the-period-when the first pair is not operating
thereon, without-imparting-any-rotation-to-the-object. Consequently, with the use
of-two-sets-of-rolls arranged one-behind-the other working in contrary directions, the
step-by-step-forward-and intermediate-retrograde-motion of the metal-object, us-also
its-rotation, may-be-entirely effected by the action of the rolls themselves. Generally
speaking-the-necessary-movement-of-the-metal-object will be determined--by-the
special description of relling process-which-it has to-undergo or by the-nature-of-the
metal-object-itself.
I will proceed to describe various arrangements for rolling tubes and hollow
bodies according to this invention with reference to the diagram drawings

page_text: Figures 9, 10, and 11, accompanying my Provisional Specification leaving out of
consideration the means for driving the rolls and for actuating the mandril and the
object to be operated upon. •
Figures-1-to-S-show the rolling of a tube-upon-a-eylindrical mandril-by-manns-of
rolls-which-revolve-continuously-in-the-same--direction-and-it-is-assumed--that the
nction-of-the-rolls upon the-tube-is-effeeted-during-the-forward-motion thereof;-the
rells being provided-with-excentric-or-tapering-enlibres-or-grooves.
be--brought--back--into-a-new-commencing-position-for-the-attack
The-rells A and B,-which-are-suitably supported and driven-revolve-continuously
in-the-direction-of the-arrows-1-and-2-and-have-in-addition-to-the-calibres-which-are
shown-by-way-of-example-more-particularly in Figures 12, 13, and 14, gaps-or-Aat
places-a-which-allow-of-the-retrograde motion-of-the-metal-object-W, when it-has-to
of the-rolls.
Figure 1 shows-by-way-of-example-such-a-commencing position. The tube-W
enrried-upon-the--mandril D-has-been-approached towards the-rolls A-B-to-sneh
an-extent (forward-motion)-that its front-end-is-seized by the rolls and is neted-upon
thereby in-the-manner indiented-by Figure-2.-During such nation the mandru-D
preferably (but-not-necessarily)-has-a-less-forward-motion-imparted to it than the
tube-W-(this-being-indicated-in--Figure--1)-by-the-unequal-lengths-of-the-twa
arrows-3-and-4). By the said rolling-the-front-end-of-the-tube-will-be-elongated-in
a-manner corresponding to the calibre or groove of the rolls A-and-B-until the gaps a
of-the-rolls-commence-to-come-opposite-to-eneh-other-as at Figure 2. The attack-of
the-rolls-eenses-at-this-moment and the tube-W-together-with-the-mandril-D-enn
new-be-mored-backward-in-the-direction of the arrow-5-(backward-motion)-as-the
tube-is-now-entirely freed-by-the-rolls. During such backward-motion, rotation of
the tube-together-with-the-mandril is effected round its longitudinal-axis-in-the
direction of-the-arrow-6;-so-that-at-the-next-attack-of the-rolls-other-parts-of-the
cross-section-come under operation.-The-extent-of-the-gaps-a-of-the rolls has to-be
so-made-in-proportion-to-the-backward-motion-of-the-tube-that-the latter-will not
be interfered with-by-the-rotation-of-the-rolls. As-furthermore, the-tube-moves
freely-through-the rolls during the-backward--motion-it-follows that it must be
suitably-guided-and-supported it-the-direction-of-its--longitudinal-axis-as will-be
hereinafter-explained. After-the-completion-of-the-backward-motion-of-the-tube,
Figure-3-a fresh-attack-of-the rolls--ean-take-place-by-menns of which a further
elongation-of-the-tube-will-be-effected, as indiented-at-Figure-4,-until-by-the-rotation
of-the-rolls-the-gaps-a-are-again-presented-opposite each other. During the further
rotation-of-the-rolls-A-and-B-the tube-ean-be-moved backward in-the-direction of
the-arrow--as-described-with-reference to Figure-2, und at the same time-be-turned
round-its-longitudinal-axis-in-the-direction-of-the-arrow-6,-so-us-to-be-brought-into
As-will-be-seen-from-a-comparison-of-Figures-1-and-3-the-tube-will-be-seized
a-suitable-position-for-the-next-attack-of-the-rolls.
at
each fresh-attack-of the-rolls by a-narrower portion of the calibre-thereof. If
the-rolling-operation-has-proceeded-so-far-that-the-rolls-ean-net-upon the-tube
with the narrowest-part-of-their-calibre,-no-further reduction-of--the-cross-section
of that-part-ofthe-tube-ean-take place,-so-that- on the following rolling of the
thicker-part-of the-tube, situated behind-such part, the outer diameter--can-be--no
further-reduced-at-that--point--so-that-the-front-end-of-the-tube-will-beeome
eylindrical as shown at: Figure 4. The following-backward motion of the tube
consequently-has-to-be-se-proportioned that the-tube-is-only-mored--back-so-far
that the conical part-thereof-will-be-seized-by-the-rolls-at-the-next-attack, while
the-eylindrical-end-of the--tube--will--remain behind the rolls--as-indiented--at
Figures-5-and-6. From this point-forward-the-cylindrical-part-of-the-tube-will
increase-in-length-at each-attack-of-the-rolls, and us the forward-motion of-the-tube
is-always-greater than that of the mandril as above stated, it follows that the tube-W
will-be-gradually-drawn-away-over the mandril by the rolls. If-the-forward-and
backward-motions-of-the tube-in the direction of the arrows 3 and 5-be-drawn-out-in-a
broken-line as at Figure-7-it-will-be-seen that the tube must be moved forward-during
the-rolling operation with a step by step-forward and intermediate-retrograde-motoin;

page_text: The-small-circular-arrows-in-this-figure-show at the same-time-the-attack of the
rolls-during-the--forward--motion-of-the-tube--in--the--direction-of-the-arrow 3:
For effecting-the-relative-shifting-of the--mandril-and-tube-it-is-quite-sufficient
if the mandril-be-moved-forward-during-the-forward motion of the tube-only-to-sueh
an-extent ns-it-was-previously moved backward, so that the extent of the forward
motion-in-the-direction-of-the-arrow-4 will be-equal-to-the-backward motion in-the
direction-of-the-arrow Figure 5. -To the tapering or excentric-part of-the-roll-enlibre
there is-by-preference-added;-as assumed-in-all-the-figures;-n-concentric-part so that
in this part-of-the-enlibre, a smoothing-of-the-rolled-part-of the tube will be effected
in-order that the tube-may-eventually leave the rolls-in-a-smooth-condition-as
at Figure-&
Instend-of-ennsing The rolls to attack the tube during the-forward-motion,
this may be effected during the backward motion. Figure 9 shows by way of
example the termination of such an attack where the concentric part of the
calibre is already in action. The rolls A and B revolve in the direction of the
arrows 7 and 8, and the backward motion of the tube in the direction of the arrow 9
is less than that of the mandril in the direction of the arrow 10. When the
gaps a of the rolls face each other as at Figure 10, the tube together with the
mandril can be again freely moved forward in the direction of the arrow 11 so
that a further portion of the tube is presented to the renewed attack of the rolls.
In this-ense also The forward motion will be greater than the backward motion, so
that the step by step forward and intermediate retrograde motion- shown in Fig. 11
will take place,but-whereas in-the-former-ense-the-attack-of-the-rolls-commences-nt
the-smallest-diameter-of-the-tube:-in-the-present-ense the rolling-operation-will-com-.
menee-at-the-larger-diameter thereof. There results-consequently-at-the-attnek-of
the-rolls during-the-forward-motion, Fig. 7-n-rolling operation from the thinner end
of-the-tube-towards-the-thicker-part, wherens - When the rolls attack the tube during.
the backward motion as at Fig. 11 the rolling operation will take place from the
thicker end of the tube towards the thinner end as will be readily seen
ward-motion-of-the-mandril-is-preferably-made-equal-to-the-forward-motion-of-the
tube-so-that-during-the-rolling process the tube will be pushed-along-over-the
mandril. The calibre of the rolls will of course depend upon the desired section of
the tube to be obtained. With-circular-calibres-as-nt Fig. 12-one-portion thereof is
made-oval-while the concentric-part-thereof-serving-to-smooth-the-tube-is-made-up
of two-semicircles. If-the-cross-section-of-the-tube-is-not circular but-polygonal the
eccentric-portions-of-the-enlibre can be similarly formed-us-indiented at Fig. 11-for-a
rectangular-cross section, or the desired-configuration-of-the--eross-section-may-be
imparted-only-to-the-concentric-part-of the-enlibre-serving-to-smooth-the-tube-while
the eccentric part-of-the-calibre-is-made-eirenlur-or-oval-as-at-Fig-13. Both--parts
of-the-enlibre-in-that-case-gradually-die-away into each other--If-the-cross-section-of
attack-of-the-rolls-cannot-be-made-optional, but-must-be-in-correspondence-with-the
The-back-
the-tube-after-rolling-is-not-circular-the-angle-through-which-it-is-turned-after-each
form-of-the-section-so-that-for-example,-with-a-square-section-the-tube-must-always.
be-turned-90-degrees-with-a-hexagonal--section-60-degrees--or-120-degrees. If the
eross-section-is-not-n-regular--polygon-the-rolls-re-made--with-severe!--working
description-in-cross-section-and-front-view-the-enlibres-or-grooves-being-formed-for
sections-and-a-esrresponding-number-of-gaps. Figs. 15 to 18-show-rolls-of--this
the-profiles shown-at-Figs. 10-and-20.-The-two-enlibres-k-of-the-rolls-A and B are
relatively so formed-that-the--profiles-10-and-20-are-rolled-thereby-in-the-indiented
position.
It-the-rolls-have-revolved-to-sneh-an-extent-that-the-gaps-a-thereof-are-presented
to-eneh-other-the-backward-motion-of-the-tube-and-a-ro:ation-thereof-round-its longi-
tudmal-axis-through-00-degrees-is-effected.-The-tube-is-now-seized-by-the-enlibre
-which-eorresponds-to-the-profiles-10-or-20-when--turned--through-00-degrees-as
shown-dotted-at-the-upper-sides-of-the-ralls-in-Figs:-16-and-13.-During-the-baek-
ward-motion-of-the-tube-when-the-gaps-al-of-the-rolls are presented-to-ench-other
the-tube must-be-again-turned-back-through-00-degrees for the section-shown At

page_text: Fig. 19, whereas-for-the-section-shown at Fig. 20-the tube-enn-be-turned-90-degrees
forward again.
If-the-rolls A-and B-Figs. 15-and-16-were provided with four-calibres instead of
only-two, which-would-correspond to the consecutive positions of the profile-Fig. 10
when turned-through-00-degrees, this profile could also be turned-forward 00-degrees
during the backward motion-instead of being turned-backward. Such-rolls with
several operating sections-and-gaps may also be usefully employed when-rolling
eylindrical-objects.
As-with-the-above-described-rolling-process-it-is-very-desirable to have a perfectly
reliable-seizure-of-the rolls it is-ndrisable-under-certain circumstances to form the
operating portions-of-the-rolls-with serrated or stepped projections-i-as shown at
Fig. 21 by means of which projections the tube-will-be gripped-with-inereased
friction and be thus drawn-through-the-rolls-with-eertainty.
The above described process-is-enpable-of-various-modifientions-according to the
purposes-to-which-it-is to be-applied, some-of-which have already--been-indiented.
As the rolls only operate on the tube during a portion of their rotation it follows that
it is in no way necessary to cause them to perform complete revolutions but that
they may also have a to and fro motion imparted to them. Also-in-this-ense, as above
described the rolls-mar-be-made-to-operate-either-only during the forward motion
or-only-during the-backward-motion-of the tube. Such-n-rolling-mill-with-to-and
fro-motion-of-the-rolls-
s-may- -however-also-be-so-arranged-that-the-rolls-oporate-beth
during the forward-and-the backward motion of the tabe; whereby a considerably more
rapid-mede-of-working-is-rendered-possible. This-mode-of working-is-indiented by
Fige: 22 to 20. The rolling process at the commencement-of the operation with
the-rolls-in-the-position-shown-at-Fig. 22-correspond exactly with that--described
with-reference-to-Fig. 1. The rolls-A-and-B-rotating-in-the-direction-of-the-arrows
4-and-2-seize-the-tube-W-which-moves-forward-in-the-direction of the-arrow 3,
while the mandril D-also-moves-forward; but-at-a-slower rate, this being again
indiented-by-the-unequal-lengths-of-the-arrows-3-und-1.
As soon-as-the--rolling-operation-has-been-completed-and-the-gaps-a-face-the
tube Was-at-Fig. 23,-the-rolls-remain--stationary-and-the-tube--together-with
the-mandril,-are-moved forward-in the direction of the arrow 12, while they are at the
same-time-partially-rotated round-their-longitudinal-axes-in-the-direction-of-the
arrow-6, the forward-motion-being to such an extent that they arrive-in-the-dotted
position;-so-that-the-rolls A and B at their following--backward-motion-in-the
direction-of-the-arrows 7-and-S,-at-once-seize-the-tube-at-the-thicker part-and-more
it backward in the-direction-of-the-arrow-13; while the mandril is moved in-the-same
direction-ns indicated by the arrows, but with a greater speed. Consequently whereas
in-the-former ense-the-rolls-operated from the thinner towards the thicker-part-of
the-tube-they-now-operate-in-the contrary direction-until-they-have-arrived in the
position Fig. 21, in which the action of the rolls on the tube ceases-and-the gaps-a-ot
the rolls-permit-of-a-forward-motion of the tube-together-with--the--mandril-in-the
direction of the arrow-15,-these-parts-being-at-the-same-time rotated as indicated in
dotted lines-nt-Fig. 21. In this position the tube. W is ready for n-fresh-attack-of
the rolls A and B when the latter-again-rotate in the direction-of the-arrows 1 and 2.
The tube-will-then--be-again-moved-forward-in-the direction-of the-arrow-3--and
the-inandril will-also-move-in-the-same-direction-but-with-less speed, as indiented
by the arrow-4; so that towards-the-end-of this period,-the-position-shown-at-Fig. 25
will-be-reached-in which-again a small forward motion-of-the-tube-and-mandril-in
the-direction-of-the-arrow-12 together-with-rotation-in-the-direction-of-arrow-6-enn
be effected nutil-the-tabe-is-brought-into-the-position-for-being-attacked-by-the rolls
during their rotation--in the direction of arrows-7 and 8. In this way the rolling
operation-is-further-carried on-as-indiented in various-phases-at Figs. 20, 27 and 28
and-which require-no further description.
If the movements-performed by the tube during its passage-through-the-rolls-be
drawn-out in-a-broken-line,-as at-Fig. 20, it-will-he-seen that the tube again performs
a step by step forward-and intermediate-retrograde motion. For the sake of clearness

page_text: the-several-parts-of-the-forward-and-backward-motion in this figure-are-shown-drawn
asunder-but-in-reality the shiftings-15, 3 and 12-will-follow-ench-other closely if they
ure-brought-in-proper relation to the reversed motion of the rolls.-The-step-by-step
forward-and-intermediate retrograde motion will therefore in this ense-only differ
from-that-of-Fig. in that the forward-motion-of-the tube at two- following attacks
of-the-rolls will be increased by the shiftings 12-and-15, which-results-as-already
remarked-in-n-eensiderably quicker mode of working. The-mandril-moves-forward in
the direction of the arrows 4, 12 and 15 and backward in-the-direction of the arrow-14.
The latter-motion has therefore-to-be-made-equal to the sum of-the-two-first-if-the
mandril is required to occupy the-same-position at the end of the rolling operation-ns
it-did-at-the-commencement thereof and the tube will at-each-ntinck-of-the-rolls then
be-drawn-forward-over-the-mandril. The rolls-in-this-ense-need-not--necessarily be
formed-as-complete-cylinders-at-the points beyond the enlibres Fig. 12-it-is--quite
suflicient-if-they-are-formed segmental, that is to say the cylinders being only formed
i-e-such-an-extent-ns-to-enuse them to roll-upon-ench-other-during-the-backward
Although-such-structures-may-not-strictly speaking-be-called rolls 1-will
motion:
retain this designation-us-the-working of the tubes is effected-by-n-rolling-operation
notwithstanding-the-said-shape of the rolls.
t-n-similar manner-to-the ordinary rolling mills, the rolls-employed-for the purposes
of-this-invention-may-have several-calibres-formed-side-by-side-thereon-in which the
metal-is-operated-on-either simultaneously or consecutively. With this arrangement
it-is-of-advantage-to-place-the-operating portion (Fig-16)-of-the-one-enlibre next
to-the-gap-or-next-position-a-(Fig. 15) of the contiguous-enlibre,-so-that-a-tube is
being-operated-upon in the one-calibre-while-in-the-next-enlibre-the-gaps allow of the
free-motion-of-the-tube.
Instend-of rolls-with-tapering and concentric-enlibres with gaps there may also be
employed-rolls-with-concentric-enlibres-without-gaps if in-this-ense-nt-ench-attack of
the-rolls-these-are-made-to-approach-each-other-or-to-move-away from each-otlier.
This-mode-of-operating-is-more-particularly-advantageons-when-larger metal objects
are-to-be-operated-upon. The movement-of the-rolls-may-be-advantageously effeeted
by menus-of-hydraulic-cylinders-with-pistons which-earry the-bearings-of-the-lower
rolis-as shown-nt-Figs-30-to-31-for-rolls with to and fro-motions-If-the-rolls Aand-B
operate-during-the-forward-motion of the tube Win the direction of the arrow-3Fig.30
the-lower-roll-is-made to sink-down gradually in the direction-of--the-arrow-16,-the
piston-of-each-lower-bearing being made-to--sink--down--in-its--cylinder-to-n-cor-
responding extent. The-reverse motion-in-the-direction-of the-arrow-17-Fig. 31-is
effected-by-the-pistons F-during the ntinck, of the rolls when the tube-is-being moved
backwards-in-the-direction-of-the-arrow 13. Figs. 32-to-34-show-the-further-ndrance
#nd-the-termination-of-the-rolling operation. With-this-process-the-rolls-are-made
with-oval-enlibres;-and-after-each-attack-a-partial rotation-of-the-tube-together-with
the-mandril round--its-longitudinal axis-is--necessary, for-which-purpose-the-rolls
have-to-be-mored-so-fur-apart-that they allow of the free-shifting-and-rotation of the
tube:
The required-greater-distance-apart of the rolls--nt-the-commencement--of-the
rolling-process-may-be-effected-by-the-adjustment of the upper-roll-bearings in-the
known-manner-by-means of screw spindles-and-toothed genring.
The-movement of the pistons F-is-effected by the-admission-of-fluid-pressure-from
#n-necumulator-into-the-cylinder-G-but-the-shifting of-the-position-of the-roll-may
be-effected-by-a-mechanical-device-such-as-by-a-lever-netunted-by-an-eccentric-or by
means-of-wedge-gearing as shown at Fig-on-where-the-wedges-H of both-bearings
are-moved to and fro, which will have the well-understood-nation-of-raising and
lowering the-lower-roll-The-upper roll-may-also-be-mounted-in-movable-bearings in
the-same-manner-as-the-lower-roll-and--be-raised-and-lowered during the rolling
operation, or both-rolls-enn-be-ruised-and-lowered simultaneously.
4-H-the-enses above referred to there may be employed in-place of the cylindrient
-prismatie-mandril-a-content-or-conoidal one, but-in-order-that-the-hollow-metal
object-may-be-shaped-cylindrical or prismatic it is necessary that the backward

page_text: motion-be-made-equal-to-the-forward motion in order that always-the-same-part-of
the mandril-shall-assume-the-same-position-relatively-to-the-central-plane-through
the-axes-of-the-rolls;-this-not-being-essentially-necessary-with-cylindrient-mandrils
although-it-is-preferred-for-the-moving-mechanism of the mandril. Figs:-36-te-43
show-the-rolling-operation-with-such a conical mandril the outer configuration of the
metal-object-being-at-the-same-time-also-eonien!.-The rolls A and B-are-in-thisense
provided-with-two-working sections-and-two-gaps-a-a¹:-The-working sections-have
tapering-or-eccentric-calibres-and-the-rolls-revolve-continuously-in-the-direction of
the arrows-1-and-2. In Fig. 36-the-first-attack takes place. After-the-completion
thereof,-us-at-Fig. 37, the backward-motion-of-the-metal object-together-with-the
mandril,-and-the-rotation-of-the-whole-round-the-longitudinal-axis-takes--place--us.
described-with-reference-to-Fig. 2. The five-following figures-show-various further
stages-of-the-rolling operations-while- in Fig. 13-the rolling is supposed to be
completed.
For-produeing--the outer conien! -configuration--of-the-metal--object--the-rolls
are-moved-slightly-apart-after each attack, which may be effected-for-instanee-by-the
rotation-of--the-serew-spindles-for-the-adjustment-of-the-bearings of the upper
roll. This--movement of--the serew spindles or of their driving-gear-may-be
readily-effected-by-a-ratchet-mechanism--which--is-netuated-by--one--of-the--rolls
er-in--any--other--desired-manner.
If-the-ratchet--mechanism--be-moved-to-the
same-extent for eneh-rotation of the rolls,-the-outer-configuration-of-the-metal
object will be conical or with polygonal cross-section in-the-form of the frustrumi
of a pyramid: If-on-the-other-hand-the-extent of motion of the-ratelet--gear--be
varied for-eneh rotation the metal-objeat-will--become--conoidal-or-of-eurred-form:
If-during--the--rolling-operation--the rolls--be-made-to-approach--each--other, the
rear-end-of-the-metal object will-be-thinner-than-the-front-end-thereof.
Fig. 11 shows-how-by-first moving-the-rolls away-from-ench--other-and-then
eausing them-to-approach,-hollow-bodies-of-cylindrical or-prismatie-hollows-ean-be
produced which-have-in-the-middle-thieker-walls-than-at-the-ends-such-for-exaniple
as-is-required-for-objects having equal-strength throughout-their-length. There is
no-difficulty in effeeting, by means of suitable-nctuation-of-the-ratehet-gear-for-the
adjusting-spindles-of-the-rolls;--any--desired--variation--in-the--eross--section--with
reference-to-the-longitudinal-axis-of-the-body. The same process-may--also-be
employed in combination-with-rolls having to and fro-motion, but-in-this--ease-the.
same results may-be-obtained by varying the backward-motion as by-the-adjustment
of-the-rolls, or such action-may-be-used-in--combination-with-the-said-adjustment.
This will be readily-seen--if-it-be-considered-that-the-outer-diameter-or-outer
configuration-of-the-metal-object-will-be-determined-by-the-end
at-Fig 28.
position-of-the-rolls
If the reversing-motion-of--the rolls-be-modified in-such-a manner that in place-of
the-narrower-portions-of-the-calibres-by-degrees the larger portions-operate upon the
metal-object -towards-the-end-of-the-separate attacks, a-gradually increased diameter
in the longitudinal direction of the metal-object will-result. In-a-similar-manner-a
decrease of the-diameter-may-be--effected-if-by-degrees--smaller--portions--of-the
enlibre-be-made to act upon the metal-object-at-the-end of each-rolling-operation.
The conical-or conoidal-mandril-also--allows-of-a-variation-by-the-cross-section-of
the hollow of the-metal-object in-the longitudinal-direction--if the motion of the
mandril-be-so-arranged-that thicker or thinner-parts thereof be made to-lie-in-the
central plane-of-the-rolls-at-the-end of each rolling operation.
Figs. 45-to-52-show-the-mode-of-producing a-tube-of-cylindrical outer form and
with a conical-hollow in the above-described--manner.-The--several--figures--again
represent-generally the before-described Figs. 36-to-13; but as will-be-seen-from-a
comparison of the Figs. 45, 47, 10,51 and 52 the point-of-the--mandril-is-removed
gradually from-the--central-plane-of-the--rolls-in-such-a--manner-that--towards
the--end--of-each--rolling-operation--a-thicker-part-of- the--mandril-is-situated
in-this--plane. Such movement-of--the mandril--is--effected--when-a-step-by-step

page_text: forward and intermediate retrograde-motion-is-imparted to it similar to that--of
the metal-ohjeet-as--described--with-referenee-to-Fig. 7. If this--motion-be--se
arranged-that-by-degroes, thinner parts-of-the-mandril are situated-in-the-eentral
plane-of-rolls-at-the end-of-ench-rolling-operation, the hollow will-become-gradually
narrower--instead of larger as shown at Fig. 52. Fig. 53-shows--how-by-the
combination of--both-step-by-step forward-and-intermediate-retrograde-motion,
bodies enn-be produced-which-have-external-cylindrical-or-prismatic-configurations,
while internally they-have-thicker-walls-at-the-centre-than-at-the-ends so as again-to
afford-equal-strength-in-the-direction-of-the-length. If, lastly, as-indicated--in
Figs:-51 to-61, the rolls are-also-munde-to-move-away from each other gradually
during-the-step-by-step-motion-of-the-mandril, the outer-surface-of-the-body-will
also become conical or pyramidal.--The-positions-of-the-rolls,-the-metal-object--and
the-mandril-correspond to those-nt-Figs. 45-to-52-and-after-what-has-been-stated
they-require no-further-description: In-this-ense-both motions-can-be so-arranged
that-the-thickness-of-the-walls is-equal-in-all-parts-of- the-longitudinal-uxis, or-the
thickness-of-the-walls-may-be varied. In-this-way there may also be obtained; by
suitable-alteration of the position--of-the-rolls-or-step-or-step-motion, bodies-of-the
form shown at-Fig. 62.
The-cross-section of the mandril need-not-necessarily be similar to the outer
configuration-of-the-metal-object.
In-manufacturing-the-tubes-or--hollow-bodies-with-inner--ribs the mandril will,
ns--shown-by-way-of-example-at Fig. 63, have-to-receive-corresponding recesses--x
nt-its-front-end, into which-the-metal-is-pressed-by-the-rolls during the operation.
If-the-tube-is-to-have--external-ribs. the--enlibre-of-the-rolls--must-be-made-in--a
corresponding manner,
As-above-stated, under-certain-circumstances-the-guiding-and-movement of the
metal-object-and-mandril will be required during the-rolling-operation. A portion of
this guiding-and-movement can be effected by-the-rolls A and B-themselves, but both
the mandril-and-the-tube-ean-also-be-moved-and-guided-at-both-ends.
Figs.-64-to-66-show-a-rolling-mill-with-moving mechanism of the-first-description
Ly way of example, Fig. 61 being a longitudinal-section Fig. 65 a-plan-and-Fig. 66
-vertical-section-on lines-y-y-Fig. 61. Figs.-67-to-71-shew-detached details-of-the
mechanism. The lower roll B is driven by means of the shaft-b-and-drives-the-upper
roll-by-means-of-toothed-gear-c-and-d, while-by-means-of toothed-gear-f-g-and--it
drives-the-cam-shaft-k:-On-this-shaft-k--is-a-cam-1,-which-actuates the lever-m
rocking-on-the-piret-m-by-means-of-the-roller-1: The lever n-is continuously
pressed against-the periphery-of-the-cam-1-by-a-spring 7 being guided by a
forked-piece-p-which-embraces the-lever-n--at-the axis of the roller-r-and-which
has-a-pivot-pl. The free-end-of the lever n-moves the slide u--to-and-fro-which
slides-in-the-cylindrically-bored-guide-t. On-the-central pivot-ul of this slide is
rotatably--mounted-the-socket-v, with- which the mandril D is connected.--The
seeket-Figs. 68, -60-and-70-is-stepped and contains a rotatable ratchet ring w
Figs:-70-to-73-which-is-provided-with a sloping-projection-wl-and-with-a-pawl w
which-gears-with-ratehet teeth-vt-of-socket-v-Fig. 70. The projections wl of the
ratehet ring-w-takes-into-n-helical-groove-tl-of-the-guide-t-Fig. 71 so that the
ratehet-ring-w-will be moved to and fro in-the--guide-t, during the to and fro
motion-of-the-slide-u. During the forward--motion-the-pawl-u2 of the ratchet
ring-w-will-slide--loose--over-the-teeth of of the--socket whereas during the
backward-motion-the--socket-v-will-be-carried--along-by--the-ring-w-such-motion
of-the ring and-consequently-also of the mandril D being effected through-an-angle
of-00-degrees.
The-metal-object-to-be-operated-upon, placed-upon-the-mandril D is now-earried
forward by-the-rolls A and B, while-the-motion of the mandril D which is determined
by-the-eam-will-be-somewhat-less, so that, as before-described, the metal object-will
be-simultaneously-drawn-off-from-the-mandril-during-the rolling-operation. On-the
backward motion-of-the-mundril it-carries the tube backward with it by friction,
while-at-the-same-time-the-rotation-of-the-mandril-and-tube-through an--anglo-of

page_text: 00-degrees-is-effected. The-step-by-step-motion of the tube is consequently in-this
ense-effected-by-the-action-of-the-rolls-themselves-upon-it. As the rolls A-and-B
have
two-working-sections-the-shaft-k-makes-two-revolutions-while-the-shaft-b-makes
one. Of-course-k-might-revolve at the-same-speed-ns-b-if-the-euml-were--made
double.
In-order-to-place-the-tube-upon-the-mandril-the-slide-s-is moved-back-by--menns
of the elbow-lever M and link as shown at Fig. 67, so that the spring-q-allows-the
slide-to-be-moved so far-back-that-the-mandril-D-can-be-turned-upwards-upon-the
pivot-v-2-through-the-slot-t-2-of-the-guide-t. If-it-is-desired with this arrangement
to impart-to-the-mandril-a-step-by-step forward-motion-with-intermedinte-retrogres-
sion, this-may-be-effected by gradually-shifting-the-pivot-m-of-the-lover-n. Thus
for-example-as-shewn in the drawing the pivot-m-of-the-lever-n-mar-he-mounted-on-n
slide--which-can-be-shifted-in-the-direction--of-the-mandril-D-by-means--of-n
serew-S. This shifting may be effected either-by-hand-or-automatically by means of
n-ratehet motion in any known manner-for-example-in-a-similar manner in which the
slide-rest-of-n-turning lathe-is-shifted. Fig. 70 shews another shifting arrangement
netuated by means of the pistons-of-a-hydraulie-eylinder,-the-two-ends-of-which-are
mude-to-communiente-with-an-neeumulator-by-means of pipes-having closing-and
opening-devices, so-connected that, necording as may be required. Anid-pressure-can
be-admitted-to-the-one-or-to-the-other-side-of-the-piston.
Fig. 6-shows-n-rolling-mill-of the-second above-described-arrangement-in-which
the-mandril-and-tube-are-moved-and-guided-at-both-ends, such motion-being-effected.
br-means-of-differential-levers, that is to say levers-of-unequal-length. The-tube-W
is-connected-at-its front-end-to-n boss a which may either be forged-in-one-piece
therewith-or-which-is-preferably-formed-similar to gripping tongs,-so-ns-to-enable-it
to-be-fixed-on-the-front-end-of-the-tube-nfter-it-has-been--introduced-between--the
rolls. The trunnion-b-2-of-the-boss-enn-rotate-in-the-swivel-joint-d--so-that-the
rotation-of-the-tube-enn-be-effected-without-requiring-the-swivel d-2-to-partake-of
such-motion. With-the-swivel-1-2-is-connected-n-rod-f-2-provided with-ratchet-teeth
which-passes-through-n-slot-in the-lever-h-2-and-is-carried-along-by the latter in the
direction-of-the-arrow-by-means of a ratchet--pawl-g-2. The lever-/-turns-on-
pivot and receives a to and fro motion by means of the crank pin-1-2 of the-dise-12
This motion is transmitted by a-rod-m-2-to-n-second-lever-p2 which is situated on-the
other-side-of-the-rolling-mill-and-is-pivotted-at-q²-and-which has to impart the
requisite-motion to the mandril-D. The latter is for this purpose-connected-by-n
sleeve -o-in-n-rotatable-munner to-the-lever-p2-The-point of connection-of-the
rod-m2 to the lever-/2 can be adjusted-by-means-of-a-serew-
--2-so-that-it-is-possible;
necording-to-requirements, to alter the proportion between the motion of the mandril
and-that-of-the-tube: The-erank dise 12-receives, with-the-arrangement-shown-in
which there is only one working section-on-ench-roll, the-same-number-of-revolutions
as-the rolls A and B-and-it-is-so arranged-that it causes the levers-1-2-and-p-to
perform-a-movement to--the-left-ns-soon as the gap a of the-rolls A
and--B--sets-free-the-tube W. The rotation of the latter can be effected
either by means of the hand-wheel-s-attached to the mandril D
or-a-mechanism similar-to-that-described-with reference to Figs. 61 to 66-enn--be
used. The-connection of--the--toothed--rod--/--with-the-lever-/-2-by-means-of-the
pawl-g2-renders-it-possible-for-the-tube-to-be-moved-forward-by-the-action-of-the
rolls-A-and-B-without-eausing the lever-h-2-nctuated-by-erank-dise-12-to-partake-sf
this motion. Consequently, in rolling the-tube-the mandril-D-will always perform
the-same-to-and-fro-motion, while the tube will-bo-moved-farther-forward-by-means
of-the-rolls-and-will-be-moved-backward-in-proportion to the-length-of-the-levers,
thus carrying out the-before-described step-by-step-forward-motion-with intermediate
retrogression. It will be-seen-that-during-the-working-period, that-is-to-car-during
the time when the--rolls-operate-on-the-tube, an-automatic-drawing-off-of-the-tube
from-the-mandril-will be-effected by the retarded-metion of the latter. If the lengths
of-the-levers-be-so-taken-that-at-the-backward motion-the mandril-D-moves quicker
to-the-left-then-the rod f-2-there-will-also take place a loosening between-the-mandril

page_text: "
wherein the metal-object,-during-its passage-through the-rolls-has-n--step-by-step
forward-with-intermediate-retrograde-motion-imparted to it in such manner that it is
operated-upon successively on a limited portion of its length, such point-of-operation
being-made-to-advance-in-a longitudinal-direction-along-the-object, substantially as
described...
.
2. A-process-of-forming-or-rolling-tubes-and-other-hollow-bodies upon-a-mandril
wherein-the-metal-object-is-subject-to-the-action-of-gapped-or-separable-rolls-in-such
manner that after-a-certain-length-of-the-metal-object-has-been neted-upon by the
ralls-during-its-forward motion, it is liberated from them, whereupon-it-is-drawn back
and-again-fed-forward in order to cause the-rolls to- net upon a following portion-ofits
length, substantially-as-described.
1. A process of forming or rolling tubes and other hollow bodies upon a mandril,
wherein the metal object is subject to the action of gapped or separable rolls provided
with grooves in part concentric and in part eccentric or tapering in such manner
that after a certain length of the inetal object has been acted upon by the rolls while
it is moving in a backward direction, it is liberated from them, whereupon it is moved
forward in order to be again acted upon by the rolls while moving in a backward
direction, such action taking place on a portion of the object following that which was
first acted upori, substantially as described.
4.
A-process-of-forming-or-rolling-tubes-and-other-hollow-bodies-upon-a-mandril
wherein-the-metal object is subject to the action-of-gapped-or-separable-rolls having
n-reciprocating--motion-the--metal-object-being-first-neted-upon-br-the-rolls-while
these-revolve-in-one-direction;-and-after-being then liberated thereby, the-object-is
moved forward-to-n-certain extent in the-same-direction-and-is then-again neted-upon
by-the-rolls-while-rotating-in-the contrary-direction, substantially-as-described.
5.In the process of forming-or-rolling-tubes and other-hollow bodies-upon-a
mandril-referred to in the preceding-claims effeeting-the-partial rotation of the metal
ohjeet-upon-its--longitudinal-axis-when-it-is-liberated-by-the-rolls, substantially as
deşeribed.
6. In the process of forming or rolling tubes and other hollow bodies-upon-a
mandril-referred-to-the-preceding-claims, effecting the automatic shifting of the
hollow-metal object-upon-the-mandril-during-the-rolling, operation, by-eausing the

page_text: mandril-during-such-time-to-receive-a-motion-different-from-that-of-the-metal-object
substantially-as-described.
7. In-the-process of forming or rolling hollow metal-objects-referred to in the first
elaim,-the-method-of-producing-the-metal-object-with-varying-external-configuration
of-the-cross-sections, in-the-direction-of-its length, either-by-varying the distance
between-the-rolls-during-the-rolling-operation-or by varying the return motion-of
reciprocating-rolls having eccentric-or-tapering-calibres-in-such-a-manner that-by
degrees-different-parts-of-the calibre-are-made-to-net-upon-the-metal-substantially as
described.
8. In-the-process of forming or rolling-hollow metal-objects-referred-to-in the first
elaim,-the-method-of-producing-the-metal-object-with-varying-internal configuration
of-the-eross-sections by-imparting-to-the-mandril-a-motion-in such manner that-its
middle-position-relative-to-the-vertical-axial-plane-of-the-rolls-is-varied-during-the
operation-substantially-as-described.
0. In-the-process of forming or rolling-hollow-metal-objects-referred-to-in-the-first
elaim, varying both-the-internal-and-external-configurations-oftthe-metal-object by
combining-the-methods of operating referred-to-in-the-7th-and-2th claims.
10.-The-construction-of rolling mills for-carrying out the process referred to-in-the
first-claim-wherein the rolls-are--made-to-approach-and-recede-from-each-other
periodically, substantially as and-for-the-purposes-described:
11. The construction of rolling-mills-for-earrying out the-process-referred to in the
first-claim, wherein the rolls are provided with projecting parts for operating upon the
metal-object and with-gaps-or-receding-surfaces-for-allowing--of-the-free-backward
motion-of-the-metal-object,-substantially-as described.
2. 12. In rolling mills such as are shown in figures 9 and 10 referred-to-in-the
preceding elnim; providing the projecting parts with calibres or grooves in part
concentric-or-excentric, or-both concentric and in part excentric or tapering ealibres
or-grooves, substantially as described.
13. In-rolling-mills sneh-as-are-referred-to-in-the-preceding-claims,
effecting-the
movement-of-the-metal-object-by-means-of-the-rolls-operating in-combination with a
reciprocating-mandril-which-in-combination-with-the-rolls--imparts-a-reciprocating
motion-to-the-metal object, substantially-as-described.
14. In-rolling mills-such-as-are-referred-to-in-the-preceding claims, effecting the
movement-of-the-mandril-by-means-of-a-reciprocating lever, the-length-of-which-or
the-position of whose-fulerum-enn-be-varied-for-produeing a-step-by-step-forward-and
intermediate-retrograde-motion, or other change-of-position-of-the-mandril-substan-
tially as described.
Dated this 23rd day of November 1801
ABEL & IMRAY,
Agents for the Applicant.