the Construction and Use of Apparatus for Enlarging metalo
Year: 1887

page_text: Date of Application, 3rd May, 1887.
Specification Accepted, 14th June, 1887.
[Communicated from abroad by REINHARD MANNESMANN and MAX MANNESMANN,
both of Remscheid, in the Empire of Germany, Manufacturers.]
the Construction and Use of Apparatus for
Enlarging metalo
I JOSEPH THEODORE DANN, of 32 Canterbury Road, Brixton, in the County of
Surrey, gentleman, 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 is an improvement upon and a further development of the method
of transforming solid ingots of metal into tubes by means of diagonally-acting rolls
impinging upon different sides of the blank which is described in the specification
accompanying the application for Letters-patent filed by Reinhard Mannesmann and
Max Mannesmann on August 3rd 1886 and numbered 9939-1886; and it consists
in progressively compressing the sides or shell of the tube upon the surface of a
conical or conoidal mandrel, and in simultaneously forcing the metal to move spirally
around the mandrel from the smaller extremity towards and over the base of such
mandrel. To this effect I construct a conical or conoidal mandrel of suitable taper
and dimensions, and in combination therewith a pair of diagonally-acting hemi-
spheroidal or paraboloidal rolls, the working faces of which diverge from the place
where they compress the shell of the tube upon the smaller part of the mandrel to or
beyond the place where the greatest enlargement in the size of the tube is effected,
and where its shell becomes thinnest.
The tube which is to be enlarged may be fed while still hot from the machine in
which it is formed into another machine which enlarges it, or may be re-heated
preparatory to being enlarged; or a solid metallic blank may be progressively
transformed into a tube, and the tube enlarged to the requisite extent by means of
diagonally-acting rolls having the portions of their working faces which first engage
the blank convergent, for the purpose of developing the tubular formation, and the
rest of their faces divergent, for the purpose of compressing and drawing the outside
D
071

page_text: or shell of the tubular formation upon and over the surface of the mandrel interposed
midway between them. By this method a solid blank may, at one or more heats and
by one or more passages through the rolls, be transformed into a tube the shell of
which is composed of spirally overlaid fibres of metal and the external diameter
of which exceeds the width of the narrowest part of the space between the rolls.
.
In the accompanying drawings I have shewn first, the apparatus for enlarging
the sizes of tubes; secondly, tube-enlarging mechanism arranged in close proximity
to the diagonally-acting reducing rolls for transforming a solid blank into a
tube; and thirdly, pairs of hemispheroidal or paraboloidal rolls having portions of
their working faces convergent for the purpose of developing the tubular formation in
the blank, and having the remaining portions of their faces divergent; combined with
an interposed conoidal mandrel for the purpose of pressing upon and drawing
over the surface of the conoidal mandrel the shell of the tubular formation thus
developed.
Figure 1 is a plan of a pair of hemispheroidal rolls mounted upon the opposite ends
of two convergent shafts, and arranged at slightly different elevations on opposite
sides of the conoidal mandrel, for the purpose of enlarging the size of a tube or
hollow blank fed into the narrow end of the space between the working faces of the
rolls.
Figure 2 is a plan of a pair of the tube-enlarging rolls and an interposed conoidal
mandrel, arranged in intermediate proximity to a pair of diagonally-acting reducing
rolls impinging upon opposite sides of a solid blank, showing the development of the
tubular formation in the blank, and the subsequent enlarging operation.
Figure 3 is a plan of a pair of hemispheroidal rolls mounted upon the opposite ends
of two converging shafts, and having suitable portions of their working faces con-
vergent, and the remaining portions divergent; showing a conical mandrel interposed
between the divergent portions of the working faces, and also showing, in longitudinal
section, à solid metallic blank which has been seized by the convergent portions of the
working faces, and has commenced its passage between the rolls.
Figure 4 is a similar view, representing the blank as having so far progressed
between the rolls that there has been formed at its forward end a tubular recess into
which the pointed end of the mandrel projects.
Figure 5 is a similar view upon a larger scale, shewing the blank at a further stage
of its progress, in which the forward portion of it has been transformed into a tube of
larger diameter than the original diameter of the blank. Figure 6 is an elevation of
the rolls and blank shown in Figure 5.
Figure 7 is a view, similar to Figures 3 and 4, of the rolls and mandrel, showing
the blank so far progressed between the rolls that its rear end has been carried nearly
to the point of the mandrel; and Figure 8 is a view of the rolls and mandrel
similar to Figure 5, shewing the conclusion of the tube-forming and enlarging
operation.
A close resemblance exists between the arrangement of the diagonally-acting rolls
and mandrel for enlarging the diameter of a hollow ingot or thick-shelled tube, and
the arrangement of diagonally-acting rolls and mandrel for progressively transforming
a solid blank into a tube and then immediately enlarging such tube in size. In all
cases there is required to be such proportioning of the distance between the working
faces of the rolls and the diameter of the blank as will enable the rolls to grasp the
blank firmly and by their diagonal action thereon, respectively in opposite directions,
impart both a rotary and a forward movement to the metal which they displace. If
the blank is hollow or in the form of a tube having a thick shell, and the object of the
operation is simply to enlarge the external diameter of the tube, and to reduce the
thickness of the shell, then there will be required only a comparatively moderate
depth of impingement for those portions of the working faces of the rolls which first.
seize the blank. This is illustrated in Figure 1, in which, as will be seen, the portions
of the hemispheroidal rolls which most nearly approach each other produce, in seizing
´upon the end of the blank, a comparatively slight reduction in its diameter.

page_text: Hemispheroidal or paraboloidal rolls such as those shown in the other figures are
designed to effect by their preliminary action a comparatively large reduction in the
diameter of the blank, for the purpose of developing a tubular formation therein, as
illustrated in Figure 4, according to the method described in the aforesaid application
No. 9939-1886.
The rolls shown in Figure 1 are especially intended for the transformation of a
thick-shelled tube or hollow blank into a very thin-shelled tube of greatly increased
external diameter. The rolls A, a, are mounted respectively upon the opposite ends
of the converging shafts B b. The central portion, C, of the working face of each
roll is spherically rounded, and the remaining portion C₁, is conical. The vertical
planes of the axes of the rolls A a, meet each other, and intersect at or near the same
point, the vertical plane of the axis of the blank D; and the bevelled portions, C¹, of
the two rolls are frustra of cones the apices of which would meet at or near the line of
intersection of the vertical planes of the axis of the rolls.
The roll A rotates in the direction indicated by the arrow A¹, and hence at its line
of impingement upon the blank acts in an inclined downward and forward direction.
The roll a rotates in the direction indicated by the arrow a', and at its line of
impingement upon the blank acts in an inclined upward and forward direction. There
is thus imparted to the blank, D, a rotation upon its longitudinal axis in the direction
indicated by the arrow D' and also an end wise forward movement in the direction
indicated by the arrow D³.
By the motion imparted to it the blank is carried forward over the surface of
the conical mandrel E, the pointed end, e, of which enters the hole d in the blank.
It will be seen that the angles of the working faces of the rolls with the axis of the
blank are slightly more acute than the angles of the sides of the conical mandrel with
its axis, and hence as the tube is forced forward over the surface of the mandrel its
shell d', is gradually reduced in thickness.
The tube-enlarging rolls, and a mandrel of the type shown in Figure 1, may be
arranged in intermediate proximity to tube-forming rolls worked according to the
process described in the application No. 9939-1886 as illustrated in Figure 2, in
which the tubular formation is initiated in a solid blank during its passage through
the convergent working faces of the rolls F, f, and its path of movement between the
rolls F, is in alignment with its path of movement between the enlarging
rolls A. u.
Instead, however of employing one pair of rolls for transforming a solid blank into
a tube, and another adjoining pair to enlarge such tube, the said processes of trans-
forming and enlarging can be performed by a single pair of rolls of the type
illustrated in Figure 3, in which there is shown a solid blank, D, which has been
seized by the converging portions of the working faces of the rolls G, g, and has
already had a recess formed in its forward end by the pinching action of the rolls.
In Figure 4, the blank 1) has so far progressed between the convergent portions
of the working faces of the rolls G g, that its external diameter is considerably
reduced and the recess d' at its forward end has increased in depth by the rupturing
of the metal along the line of the axis of the blank and the outward movement of the
metal therefrom; and now the point e of the conical mandrel E, has entered the
recess d¹.
As shown in Figure 5, the tubular portion of the blank is forced forward over, and
compressed upon the surface of the mandrel E by the continued action upon it of the
rolls, and is thereby transformed into a comparatively thin-shelled tube.
Rolls of the type shown in Figures 1 and 5 and the other similar figures, are
mounted upon converging shafts the axes of which are respectively in parallel planes
which are equidistant from the axis of the blank, as illustrated in Figure 6, in which,
as in all the other figures represented in the drawings, it is assumed that two rolls are
employed, and that they are respectively arranged upon opposite sides of the path
through which the blank travels. In this class of machines, when two rolls are
employed, it is usual to provide a support H, upon which the blank can rest while
passing between the rolls, as shown in Figure 6.

page_text: In Figure 7 the blank is represented as having so far progressed between the rolls
that its rear end has been carried nearly to the pointed end of the mandrel. There is
still, however, a portion of the rear end of the blank which has not yet progressed
beyond the converging portions of the rolls, and which is yet to be reduced in
external diameter by the impingement upon it of the converging working faces of
the rolls.
If, however, the hold of the rolls upon the blank is not sufficient to force the rear
portion of the blank forward over the mandrel, then that portion may be cut off from
the enlarged tubular portion D.
The surface of the mandrel employed may, without departing from the invention,
be curved in the direction of the length of the mandrel; and similarly, the portions
of the working faces of the rolls adjacent to the mandrel may be so shaped as to have
a more or less curved line of impingement upon the shell of the tube which is in
process of being enlarged.
When the operations of developing a tubular formation in a solid blank, and of
enlarging the size of such tubular formation, are performed together during a single
passage of the blank between the rolls, it is important that the twist which is imparted
to the portion of the blank operated upon by the convergent working faces of the rolls,
shall not be taken out in the following operation, because the tube is greatly
strengthened against internal pressure when the fibres are overlaid spirally around the
shell. The hemispheroidal or paraboloidal rolls afford the means of effectively
accomplishing this. To that end they are so shaped, and their axes are adjusted at
such an angle with respect to the path of the blank, that the vertical planes of the
apices of the cones of which the conoidal portion G¹g', of the rolls are frustra, cut
each other at or near the line of intersection of the vertical planes of the axes of the
rolls, which, as indicated in Figure 6, are arranged respectively in parallel horizontal
planes, the one above, and the other below the horizontal plane of the axis of the
mandrel.
For the present purpose it is assumed, as before, that the two hemispheroidal or
paraboloidal rolls are arranged respectively on opposite sides of a horizontal mandrel.
They might, of course, be equally well arranged, the one above and the other
below the mandrel, without changing their relations to each other and to the
mandrel.
When one pair of diagonally acting rolls is employed to develope, and a second
pair of rolls is employed to enlarge the tubular formation of a blank as illustrated in
Figure 2, the speed of rotation of the second pair of rolls may be increased to any
extent that may be necessary or desirable for the purpose of imparting to the portion
of the tube which is undergoing the process of enlargement the same or even greater
speed of rotation than the speed of rotation imparted to the tubular formation by
those portions of the tube-forming rolls which most closely approach each other, and
which have the greatest diameter.
This method of increasing the speed of rotation of the tube-enlarging rolls is
unsuited where a single pair of rolls is employed for the two purposes, first, of
developing the tubular formation, and then of enlarging the tubular formation. Hence
the importance of this hemispheroidal form which gives to the rolls the capacity of
adjustment in the manner described, whereby the ratio of increase in diameter of the
conoidal or divergent portions, Gi g', of the rolls may be made to correspond to
the ratio of increase in diameter of the portion of the tube which is undergoing the
process of enlargement, as the result of which the enlarging operation is performed
without taking out any of the twist which has been given to the fibres during the
operation of developing the tubular formation.
It should be understood that what is herein meant by the term hemispheroidal or
paraboloidal roll is a roll which is mounted preferably upon the end of a shaft, so that
its working face extends across its axis, but is approximately hemispherical or
parabolic in shape, although portions of it may be conical or conoidal; the shape of
the working faces being of such character that when two hemispheroidal or

page_text: paraboloidal rolls are mounted respectively upon the adjacent ends of two converging
shafts, the path through which the blank travels between their working faces at first
gradually diminishes in width as the working faces approach each other, and then
gradually increases in width as the working faces of the rolls recede from each other
on either side of the path of the blank.
Hemispheroidal or paraboloidal rolls having the characteristics described may be
employed instead of diagonally-acting barrel-shaped rolls for all the purposes for
which the latter are adapted in the manufacture of metallic tubing.
By making the hemispheroidal rolls of very great size, each of them might be
placed between two bearings. The great increase in size which would thereby become
necessary would, however, make the rolls inconveniently large, and it is to avoid this
inconvenience that the rolls are mounted respectively upon the opposite ends of the
converging shafts.
The hemispheroidal rolls may be regarded as bevelled rolls, having the exterior
portion of their working faces bevelled upon one angle and their interior portions
bevelled more abruptly. The form of roll shown in the drawings, however, in which
the central portion is convexly curved, is preferred, and for that reason the term
hemispheroidal is adopted as a conventional designation for rolls having the
characteristic that their diameter is greatest at the place where the enlarged tube issues
from the apparatus.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is :
1. The improvement in the art of enlarging the size of a tube or hollow metallic
ingot or blank, which consists of progressively compressing and simultaneously
drawing the shell of a metallic tube or hollow blank upon and over the surface of a
conoidal mandrel by means of diagonally-acting hemispheroidal or paraboloidal rolls,
the working faces of which impinge upon different sides of the hollow blank or tube,
and along portions of their lines of impingement diverge from each other at an angle
which is in a prescribed degree more acute than the angle of the sides of the mandrel
with each other, substantially as set forth herein and illustrated in the accompanying
drawings.
2. In apparatus for enlarging the sizes of metallic tubes or hollow ingots, or for
transforming a solid blank or ingot into a tube and then enlarging such tube, the
combination of a conoidal mandrel with diagonally-acting hemispheroidal or
paraboloidal rolls, the opposite portions of the working faces of which, adjacent to the
mandrel, are divergent, substantially as and for the purpose set forth.
3. Diagonally-acting reducing rolls proportioned and adjusted for developing a
tubular formation in a solid metallic blank or ingot, passed endwise between their
working faces, in combination with two diagonally-acting enlarging rolls, arranged on
different sides of a conoidal mandrel, and having the opposite portions of their working
faces divergent at an angle of prescribed acuteness with the axis of the mandrel, as
shewn and described.
4. In diagonal rolling apparatus, two hemispheroidal rolls, substantially as
described, the opposite portions of the working faces of which converge for a
prescribed distance and then become divergent, in combination with an interposed
mandrel, as and for the purposes set forth.
5. The improvement in the art of producing and enlarging tubes from solid billets
or blanks, which consists in first progressively reducing the diameter of the blank by
the impingement upon it of diagonally-acting reducing rolls, having their working
faces, or portions thereof, convergent, and then, aided by the impingement upon it of
diagonally-acting hemispheroidal rolls having their working faces, or portions thereof,
divergent, pressing it against and over the surface of a conoidal mandrel, placed
between the divergent working faces of such hemispheroidal or paraboloidal rolls,
whereby, during a single passage between the rolls, the blank is made to assume the
form of a tube, and such tube is gradually enlarged to a prescribed size, according

page_text: to the diameter of the mandrel, and the angles of divergence of the working faces of
the diagonally-acting hemispheroidal or paraboloidal rolls.
6. In diagonally-rolling apparatus, the combination of a mandrel, with two
hemispheroidal or paraboloidal rolls between which the mandrel is interposed, the said
rolls being mounted upon the opposite ends of converging shafts, and having the
outer portions of their working faces in the form, or approximately in the form,
of frustra of cones, the apices of which intersect a line which is perpendicular to the
axial line of the mandrel, and which is at or near the line of intersection of the planes
of the axes of the rolls, which are perpendicular to the axial line of the mandrel, as
and for the purpose set forth.

page_text: This Specification was, upon the 3rd day of March 1888, amended under
Sections 18 to 21 of the Patents, Designs, and Trade Marks Act, 1883.
[The Amendments are shown in erased and italic type.]
[Communicated from abroad by REINHARD MANNESMANN and MAX MANNESMANN,
both of Remscheid, in the Empire of Germany, Manufacturers.].
BERGISES
I JOSEPH THEODORE DANN, of 32 Canterbury Road, Brixton, in the County of
Surrey, gentleman, 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 is an improvement upon and a further development of the method
of transforming solid ingots of metal into tubes by means of diagonally-acting rolls
impinging upon different sides of the blank which is described in the specification
accompanying the application for Letters patent filed by Reinhard Mannesmann and
Max Mannesmann on August 3rd 1886 and numbered No. 1167 of 1885 and
No. 9939 of 1886; and it consists in progressively compressing the sides or shell of
the tube upon the surface of a conical or conoidal mandrel, and in simultaneously
forcing the metal to move spirally around the mandrel from the smaller extremity
towards and over the base of such mandrel. To this effect I construct a conical or
conoidal mandrel of suitable taper and dimensions, and in combination therewith a
pair of diagonally-acting hemispheroidal or paraboloidal rolls, the working faces of
which diverge from the place where they compress the shell of the tube upon the
smaller part of the mandrel to or beyond the place where the greatest enlargement in
the size of the tube is effected, and where its shell becomes thinnest.
The tube which is to be enlarged may be fed while still hot from the machine in
which it is formed into another machine which enlarges it, or may be re-heated
preparatory to being enlarged; or a solid metallic blank may be progressively
transformed into a tube, and the tube enlarged to the requisite extent by means of
diagonally-acting rolls having the portions of their working faces which first engage
the blank convergent, for the purpose of developing the tubular formation, and the
rest of their faces divergent,. for the purpose of compressing and drawing the outside
DR17

page_text: or shell of the tubular formation upon and over the service of the mandrel interposed
midway between them. By this method a solid blank may, at one or more heats and
by one or more passages through the rolls, be transformed into a tube the shell of
which is composed of spirally overlaid fibres of metal and the external diameter
of which exceeds the width of the narrowest part of the space between the rolls.
In the accompanying drawings I have shewn, first, the apparatus for enlarging
the sizes of tubes; secondly. tube-enlarging mechanism arranged in close proximity
to the diagonally-acting reducing rolls for transforming a solid blank into a
tube; and thirdly, pairs of hemispheroidal or paraboloidal rolls having portions of
their working faces convergent for the purpose of developing the tubular formation in
the blank, and having the remaining portions of their faces divergent; combined with
an interposed conoidal mandrel for the purpose of pressing upon and drawing
over the surface of the conoidal mandrel the shell of the tubular formation thus
developed.
Figure 1 is a plan of a pair of hemispheroidal rolls mounted upon the opposite ends
of two convergent shafts, and arranged at slightly different elevations on opposite
sides of the conoidal mandrel, for the purpose of enlarging the sides of a tube or
hollow blank fed into the narrow end of the space between the working faces of the
rolls.
Figure 2 is a plan of a pair of the tube enlarging rolls and an interposed conoidal
mandrel, arranged in immediate proximity to a pair of diagonally-acting reducing
rolls impinging upon opposite sides of a solid blank, showing the development of the
tubular formation in the blank, and the subsequent enlarging operation.
Figure 3 is a plan of a pair of hemispheroidal rolls mounted upon the opposite ends
of two converging shafts, and having suitable portions of their working faces con-
vergent, and the remaining portions divergent; showing a conical mandrel interposed
between the divergent portions of the working faces, and also showing, in longitudinal
section, a solid metallic blank which has been seized by the convergent portions of the
working faces, and has commenced its passage between the rolls.
Figure 4 is a similar view, representing the blank as having so far progressed
between the rolls that there has been formed at its forward end a tubular recess into
which the pointed end of the mandrel projects.
Figure 5 is a similar view upon a larger scale, shewing the blank at a further stage
of its progress, in which the forward portion of it has been transformed into a tube of
larger diameter than the original diameter of the blank. Figure 6 is an elevation of
the rolls and blank shown in Figure 5.
Figure 7 is a view, similar to Figures 3 and 4, of the rolls and mandrel, showing
the blank so far progressed between the rolls that its rear end has been carried nearly
to the point of the mandrel; and Figure 8 is a view of the rolls and mandrel
similar to Figure 5, shewing the conclusion of the tube-forming and enlarging
operation.
A close resemblance exists between the arrangement of the diagonally-acting rolls
and mandrel for enlarging the diameter of a hollow ingot or thick-shelled tube, and
the arrangement of diagonally-acting rolls and mandrel for progressively transforming
a solid blank into a tube and then immediately enlarging such tube in size. In all
cases there is required to be such proportioning of the distance between the working
faces of the rolls and the diameter of the blank as will enable the rolls to grasp the
blank firmly and by their diagonal action thereon, respectively in opposite directions,
impart both a rotary and a forward movement to the metal which they displace. If
the blank is hollow or in the form of a tube having a thick shell, and the object of the
operation is simply to enlarge the external diameter of the tube, and to reduce the
thickness of the shell, then there will be required only a comparatively moderate
depth of impingement for those portions of the working faces of the rolls which first
seize the blank. This is illustrated in Figure 1, in which, as will be seen, the portions
of the hemispheroidal rolls which most nearly approach each other produce, in seizing
upon the end of the blank, a comparatively slight reduction in its diameter.

page_text: Hemispheroidal or paraboloidal rolls such as those shown in the other figures are
designed to effect by their preliminary action a comparatively large reduction in the
diameter of the blank, for the purpose of developing a tubular formation therein, as
illustrated in Figure 4, according to the method described in the aforesaid application
No. 9939-1886.
The rolls shown in Figure 1 are especially intended for the transformation of a
thick-shelled tube or hollow blank into a very thin-shelled tube of greatly increased
external diameter. The rolls A, a, are mounted respectively upon the opposite ends
of the converging shafts B b. The central portion, C, of the working face of each
roll is spherically rounded, and the remaining portion C, is conical. The vertical
planes of the axes of the rolls A a, meet each other, and intersect at or near the same
point in the vertical plane of the axis of the blank D; and the bevelled portions, C¹¹,
of the two rolls are frustra of cones the apices of which would meet at or near the line
of intersection of the vertical planes of the axies of the rolls.
The roll A rotates in the direction indicated by the arrow A¹, and hence at its line
of inpingement upon the blank acts in an inclined downward and forward direction.
The roll a rotates in the direction indicated by the arrow a¹, and at its line of
impingement upon the blank acts in an inclined upward and forward direction. There
is thus imparted to the blank, D, a rotation upon its longitudinal axis in the direction
indicated by the arrow D₁ near d' and also an end wise forward movement in the
direction indicated by the arrow D³.
By the motion imparted to it the blank is carried forward over the surface of
the conical mandrel E, the pointed end, e, of which enters the hole d in the blank.
It will be seen that the angles of the working faces of the rolls with the axis of the
blank are slightly more acute than the angles of the sides of the conical mandrel with
its axis, and hence as the tube is forced forward over the surface of the mandrel its
shell d', is gradually reduced in thickness.
The tube-enlarging rolls, and a mandrel of the type shown in Figure 1, may be
arranged in intermediate immediate proximity to tube-forming rolls worked according
to the process described in the application No. 9939-1886 as illustrated in
Figure 214, in which the tubular formation is initiated in a solid blank during its
passage through the convergent working faces of the rolls F, f, and its path of
movement between the rolls F, f, is in alignment with its path of movement between
the enlarging rolls A a.
Instead, however of employing one pair of rolls for transforming a solid blank into
a tube, and another adjoining pair to enlarge such tube, the said processes of trans-
forming and enlarging can be performed by a single pair of rolls of the type
illustrated in Figure 3, in which there is shown a solid blank, D, which has been
seized by the converging portions of the working faces of the rolls G, g, and has
already had a recess formed in its forward end by the pinching action of the rolls.
In Figure 4, the blank D has so far progressed between the convergent portions
of the working faces of the rolls G 9, that its external diameter is considerably
reduced and the recess d' at its forward end has increased in depth by the rupturing
of the metal along the line of the axis of the blank and the outward movement of the
metal therefrom; and now the point e of the conical mandrel E, has entered the
recess d¹.
As shown in Figure 5, the tubular portion of the blank is forced forward over, and
compressed upon the surface of the mandrel E by the continued action upon it of the
rolls, and is thereby transformed into a comparatively thin-shelled tube.
Rolls of the type shown in Figures 1 and 5 and the other similar figures, are
mounted upon converging shafts the axes of which are respectively in parallel planes
which are equidistant from the axis of the blank, as illustrated in Figure 6, in which,
as in all the other figures represented in the drawings, it is assumed that two rolls are
employed, and that they are respectively arranged upon opposite sides of the path
through which the blank travels. In this class of machines, when two rolls are
employed, it is usual to provide a support H, upon which the blank can rest while
passing between the rolls, as shown in Figure 6.

page_text: In Figure 7 the blank is represented as having so far progressed between the rolls
that its rear end has been carried nearly to the pointed end of the mandrel. There is
still, however, a portion of the rear end of the blank which has not yet progressed
beyond the converging portions of the rolls, and which is yet to be reduced in
external diameter by the impingement upon it of the converging working faces of
.the rolls.
If, however, the hold of the rolls upon the blank is not sufficient to force the rear
portion of the blank forward over the mandrel, then that portion may be cut off from
the enlarged tubular portion D.
The surface of the mandrel employed may, without departing from the invention,
be curved in the direction of the length of the mandrel; and similarly, the portions
of the working faces of the rolls adjacent to the mandrel may be so shaped as to have
. a more or less curved line of impingement upon the shell of the tube which is in
process of being enlarged.
When the operations of developing a tubular formation in a solid blank, and of
enlarging the size of such tubular formation, are performed together during a single
passage of the blank between the rolls, it is important that the twist which is imparted
to the portion of the blank operated upon by the convergent working faces of the rolls,
shall not be taken out in the following operation, because the tube is greatly
strengthened against internal pressure when the fibres are overlaid spirally around the
shell. The hemispheroidal or paraboloidal rolls afford the means of effectively
accomplishing this. To that end they are so shaped, and their axes are adjusted at
such an angle with respect to the path of the blank, that the vertical planes of the
apices of the cones of which the conoidal portion G¹ g¹, of the rolls are frustra, cut
each other at or near the line of intersection of the vertical planes of the axes of the
rolls, which, as indicated in Figure 6, are arranged respectively in parallel horizontal
planes, the one above, and the other below the horizontal plane of the axis of the
mandrel.
For the present purpose it is assumed, as before, that the two hemispheroidal or
paraboloidal rolls are arranged respectively on opposite sides of a horizontal mandrel.
They might, of course, be equally well arranged, the one above and the other
below the mandrel, without changing their relations to each other and to the
mandrel.
When one pair of diagonally acting rolls is employed to develope, and a second
pair of rolls is employed to enlarge the tubular formation of a blank as illustrated in
Figure 2, the speed of rotation of the second pair of rolls may be increased to any
extent that may be necessary or desirable for the purpose of imparting to the portion
of the tube which is undergoing the process of enlargement the same or even greater
speed of rotation than the speed of rotation imparted to the tubular formation by
those portions of the tube-forming rolls which most closely approach each other, and
which have the greatest diameter.
This method of increasing the speed of rotation of the tube-enlarging rolls is
unsuited where a single pair of rolls is employed for the two purposes, first, of
developing the tubular formation, and then of enlarging the tubular formation. Hence
the importance of this hemispheroidal form which gives to the rolls the capacity of
adjustment in the manner described, whereby the ratio of increase in diameter of the
.conoidal or divergent portions, G¹g', of the rolls may be made to correspond to
the ratio of increase in diameter of the portion of the tube which is undergoing the
process of enlargement, as the result of which the enlarging operation is performed
without taking out any of the twist which has been given to the fibres during the
operation of developing the tubular formation.
It should be understood that what is herein meant by the term hemispheroidal or
paraboloidal roll is a roll which is mounted preferably upon the end of a shaft, so that
its working face extends across its axis, but is approximately hemispherical or
parabolic in shape, although portions of it may be conical or conoidal; the shape of
the working faces being of such character that when two hemispheroidal or

page_text: paraboloidal rolls are mounted respectively upon the adjacent ends of two converging
shafts, the path through which the blank travels between their working faces at first
gradually diminishes in width as the working faces approach each other, and then
gradually increases in width as the working faces of the rolls recede from each other
on either side of the path of the blank.
Hemispheroidal or paraboloidal rolls having the characteristics described may be
employed instead of diagonally-acting barrel-shaped rolls for all the purposes for
which the latter are adapted in the manufacture of metallic tubing.
By making the hemispheroidal rolls of very great size, cach of them might be
placed between two bearings. The great increase in size which would thereby become
necessary would, however, make the rolls inconveniently large, and it is to avoid this
inconvenience that the rolls are mounted respectively upon the opposite ends of the
converging shafts.
The hemispheroidal rolls may be regarded as bevelled rolls, having the exterior
portion of their working faces bevelled upon inclined at one angle to the axis and their
interior portions bevelled more abruptly inclined at a greater angle. The form of roll
shown in the drawings, however, in which the central portion is convexly curved, is
preferred, and for that reason the term hemispheroidal is adopted as a conventional
designation for rolls having the characteristic that their diameter is greatest at the
place where the enlarged tubes issue from the apparatus.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is :
1. The improvement in the art of enlarging the size of a tube or hollow metallie
ingot or blank, which consists of progressively compressing and simultaneously
drawing the shell of a metallic tube or hollow blank upon and over the surface of a
conoidal mandrel by means of diagonally acting hemispheroidal or paraboloidal rolle,
the working faces of which impinge upon different sides of the hollow blank or tube,
and along portions of their lines of impingement diverge from each other at an angle
which is in a prescribed degree more neute than the angle of the sides of the mandrel
with each other, substantially as set forth herein and illustrated in the accompanying
drawings.
2. (1), In apparatus for enlarging the sizes of metallic tubes or hollow ingots, or
for transforming a solid blank or ingot into a tube and then enlarging such tube, the
combination of a conoidal mandrel with diagonally-acting hemispheroidal er
paraboloidal rolls, the opposite portions of the working faces of which, adjacent to the
mandrel, are divergent, substantially as and for the purpose set forth.
3. Dingonally acting reducing rolls proportioned and adjusted for developing a
tubular formation in a solid metallic blank or ingot, passed-endwise between their
working faces, in combination with two diagonally acting enlarging rolls, arranged on
different sides of a conoidal mandrel, and having the opposite portions of their working
faces divergent at an angle of prescribed acuteness with the axis of the mandrel, as
shewn and described.
4. In dingonal rolling apparatus, two hemispheroidal rolls, substantially as
described, the opposite portions of the working faces of which converge for a
prescribed distance and then become divergent, in combination with an interposed
mandrel, as and for the purposes set forth.
5. The improvement in the art of producing and enlarging tubes from solid billets
or blanks, which consists in first progressively reducing the diameter of the blank by
the impingement upon it of diagonally acting reducing rolls, having their working
faces, or portions thereof, convergent, and then, aided by the impingement upon it of
diagonally acting hemispheroidal rolls having their working faces, or portions thereof,
divergent, pressing it against and over the surface of a conoidal mandrel, placed
between the divergent working faces of such hemispheroidal or paraboloidal rolls,
whereby, during a single passage between the rolls, the blank is made to assume the
form of a tube, and such tabe is gradually enlarged to a prescribed size, according

page_text: to the diameter of the mandrel, and the angles of divergence of the working faces of
the diagonally acting hemispheroidal or paraboloidal rolls.
6. (2), In diagonally-rolling apparatus, the combination of a mandrel, with two
hemispheroidal or paraboloidal rolls between which the mandrel is interposed, the said
rolls being mounted upon the opposite ends of converging shafts, and having the
outer portions of their working faces in the form, or approximately in the form,
of frustra of cones, the apices of which intersect a line which is perpendicular to the
axial line of the mandrel, and which is at or near the line of intersection of the those
planes of passing through the axes of the rolls, which are have their intersections
perpendicular to the axial line of the mandrel, as and for the purpose set forth.
Dated this 3rd day of Mov 1887