Improvements in Mechanism for Making Tubes from Metallic Ingots or Blanks.
Year: 1897

page_text: Improvements in Mechanism for Making Tubes from Metallic
Ingots or Blanks.
I, JOHN AITON CHARNOCK, of Greenville, County of Mercer, State of Pennsylvania,
United States of America, Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to improvements in mechanism or apparatus for making tubes.
for metallic ingots or billets. Its objects are to pierce metallic ingots or blanks in a
heated state and to roll or draw them out into tubular form without subjecting them
to torsional strain or materially disturbing the longitudinal arrangement of the fibres
of the metal, and the mechanism for accomplishing these objects consists of a pair of
specially constructed and arranged rolls, or a roll and a disc, working in conjunction
with a mandrel located in the pass between the rolls or between the disc and the
roll, by means of which the heated blank or billet may be pierced and drawn at one
operation.
In this operation a blank or billet is passed between the adjacent faces of the two
rolls or the adjacent faces of a roll and a disc, which impart to it a rotary motion, and
at the same time a longitudinal motion which forces it against and over the conical
piercing mandrel lying in the path of the axis of the blank, the arrangement of the
working surfaces of the rolls being such that a practically uniform speed of rotation
is imparted to each and every portion of the billet or blank lying between and being
acted upon by them, thus producing a drawing action upon the blank that does not
materially alter the longitudinal arrangement of the fibres in the blank or in the
final product thereof during any changes wrought in its diameter or form.
In the practice of my invention rolls revolving in the saine direction are so shaped
and located relatively to each other as to form between their adjacent peripheral
surfaces a pass through which a heated billet or blank is drawn and thence forced
upon the point of a mandrel which pierces its centre and converts it from a solid into
tubular form.
These rolls are tapering in shape, each being in the form of a frustrum of a cone,
the one roll having its smallest diameter at the entrance side of the pass and its

page_text: largest diameter at the exit side of the pass, while the other roll has its largest
diameter at the entrance side of the pass, and its smallest diameter at the exit side
of the pass. By this disposition of the parts, the larger diameter of the second roll
is opposed to the smaller diameter of the first roll, at one end of the pass, while at the
other end of the pass, the smaller diameter of second roll, is opposed to the larger
diameter of the first roll. As a result of this, the speed of rotation, imparted to the
billet by the rolls at all points through the pass, is equal to the mean speed of rota-
tion of the two rolls at the centre, where their diameters are equal; at all other
points in the pass at either side of this central line the greater speed of the larger
diameter of one roll is neutralized by the lesser speed of the smaller diameter of the
roll opposed to it. The speed of rotation therefore imparted by the rolls to all parts
of the billet lying in the pass and gripped by them is uniform, consequently no twist
or material alteration of the longitudinal arrangement of the fibres of the billet is
produced.
The axes of the rolls are set at such angles as will produce a forward feed of the
billet as well as its rotation by the rolls, in a manner well understood to those familiar
with the art.
The rolls are also so disposed that the sides of the pass gradually converge as they
approach the exit end so that the pass is narrower at that point than at the entrance
end. This ensures a constant and continuing grip of the rolls on the billet that
causes it to move endwise with considerable force while it is being rotated. The
point of the mandrel is suitably located at or near the exit side of the pass and
directly in the axial line of the path of the billet, so that as the latter is rotated and
fed endwise by the revolving rolls it encounters this point of the mandrel and being
pierced thereby slips up over the head of the mandrel and passes off in tubular
form.
The rolls are formed with converging surfaces, to gradually diminish the width of
the pass towards its exit end to rotate and feed forward the billet against the point
of the mandrel, which lies mainly outside of the space between the rolls.
As a result of this the billet is forced upon and simply pierced by the mandrel and
no attempt is made to smooth or finish the tubular product either during or after the
piercing operation.
However the rolls may be formed with prolongations on the exit side of the pass,
which prolongations extend to or slightly beyond the head of the piercing mandrel
and are so shaped relatively to the head that they continue to act upon the billet as
it is being pierced by said head, compacting the metal and finishing it both on its
inner and outer sides so that the tubular product leaves the head of the mandrel in
a smooth and finished condition.
In a modification I may employ a roll and a disc, with a piercing mandrel located
in the pass between them, arranged relatively to each other and operating to produce
substantially the same effect as the pairs of rolls herein before described. In this
arrangement the axes of the roll and disc are arranged nearly at right angles to each
other and the surfaces of the roll and discs, are so shaped and relatively located as to
produce between them a pass, gradually diminishing in width from its entrance end
to the point where it is intercepted by the piercing mandrel from which point it 4
slightly increases in width at each side of the mandrel so as to work upon and finish
the tubular product the same as the rolls last described.
The axis of the pass may be slightly above or below the plane of the axis of the
disc, and the axis of the roll may be inclined relatively thereto for the purpose of
producing the endwise feed of the billet.
The disc and roll revolve in such manner as to impart to the billet gripped between
them a rotary as well as an endwise movement.
5

page_text: Improvements in Mechanism for Making Tubes from Metallic
Ingots or Blanks.
I, JOHN A. CHARNOCK, of Greenville, County of Mercer, State of Pennsylvania,
United States of America, Engineer, do hereby declare the nature of this inven-
tion 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 apparatus for rolling tubes of the kind described in the
Specification of Letters Patent granted to Ralph Charles Stiefel No. 23702 of 1895,
which has for its object to roll or draw out metallic ingots or blanks in a heated state
without subjecting the metal to torsional strain or materially disturbing the longi-
tudinal arrangement of the fibres. The mechanism comprises a pair of rolls, or a roll
and a disc, working in conjunction with a mandrel located in the pass between the
rolls or between the disc and the roll.
By this process a solid or hollow blank may be pierced and converted into a tube,
which may, if desired be afterwards expanded to the required diameter by passing it
again through the apparatus when the size of the mandrel, and if necessary of the
pass, has been suitably adjusted.
In the accompanying drawings,
Figures 1, 3, and 5 are plans partly in section of various arrangements of rolls all
according to this invention and
Figures 2, 4, and 6 are side elevations of the arrangements shown in Figures 1, 3,
and respectively.
Like letters indicate like parts throughout the drawings.
With reference first to Figures 1 and 2
A and B are rolls each having two peripheral working surfaces a a¹ and b, 6¹ in the
form of frusta of cones. In the case of the roll B the two frusta forming the working
surfaces b and b¹ have a common base, and the apices of the cones would lie one on
each side of the roll. In the roll A however, the smaller diameter of the frustum
formed by the working surface a constitutes the larger diameter of the other frustum
formed by the working surface a¹, that is to say the apices of both cones would lie
on one side of the roll.
The rolls A and B are so placed that a gap or pass C which gradually tapers from
each end is formed between their adjacent peripheral surfaces. A conical mandrel D
is placed in the axial line of the pass C with its point at or near the narrowest portion
of the pass.
If a billet or blank E is introduced at the end of the pass opposite to
the mandrel D, it is drawn by the action of the rolls, forced over the mandrel and
caused to take the form of a tube. The length of the surfaces, a¹ and b¹ is preferably
equal to, or slightly greater than the length of the conical portion of the mandrel D,
and these surfaces are so shaped relatively to this part that they continue to act upon
the billet E after it has been pierced, thus smoothing or finishing the tube before it
leaves the pass C.
The motion of the billet E is both rotary and longitudinal since the rolls A and B
revolve in the same direction, as indicated by the arrows, and their axes are set at
such angles to the axis of the pass C that the billet is fed forward by the rotation of
the rolls, which grip it firmly owing to the tapering of the pass C.
In Figures 3 and 4 a roll B, similar to the roll B described above, is shown working
in combination with a disc F, having working surfaces ƒ ft. The arrows indicate the
direction of rotation of the roll B and disc F. In order to obtain the necessary for-
ward feed of the billet E, the axis of the disc F is slightly out of the plane of the
axis of the pass C, and the axis of the roll B is inclined relatively to the axis of the

page_text: pass as is clearly shown in Fig. 4. The axes of the roll B and disc F' are substantially
at right angles to each other, see Fig. 3. In other respects this arrangement is
similar to that already described and illustrated in Figs. 1 and 2.
It is not absolutely necessary to finish the tube after it has been pierced by the
mandrel D, a comparatively rough tube being sufficient for many purposes. In this
case each roll may comprise only one working surface.
The arrangement illustrated in Figs. 5 and 6 shows by way of example, rolls A¹
and B which correspond to the rolls A and B shown in Figs. 1 and 2 except
for the fact that the working surfaces a¹ and 6' of the latter are omitted. A similar
modification may obviously be made if desired in any of the other arrangements
herein described.
In all the arrangements which have been described, the angles at which the axes
of the rolls are set relatively to the axial line of the pass, and the relative diameters
of the opposing working surfaces, are so arranged that the billet in its passage through
the pass is not subjected to any appreciable twist, that is to say, there is practically
no disturbance of the longitudinal arrangement of the fibres of the metal.
If desired mechanism may be provided for rotating the mandrel or this may be left
free to be rotated by the tube passing over it.
It is obvious that after a tube has been formed from a blank in the above described
way, it may be expanded by again passing it between the rolls after the size of the
mandrel and if necessary of the pass, has been altered.
Guides or supports may be used for the billets, but these together with the
bearings and driving mechanism for the rolls are not illustrated as they form no part
of the present invention.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. In apparatus for rolling tubes a roll the working surface of which comprises two
frusta of cones whose apices would lie on one side of the roll.
2. In apparatus for rolling tubes the combination with a roll the working surface
of which comprises two frusta of cones whose apices would lie on one side of the roll,
of a roll the working surface of which comprises two frusta of cones whose apices
would lie on opposite sides of the roll.
3. In apparatus for rolling tubes the combination with a roll such as A of a roll
such as B and a mandrel substantially as described.
4. In apparatus for rolling tubes the combination with a roll such as B of a disc
and a mandrel substantially as described and shown in Figures 3 and 4.
5. In apparatus for rolling tubes the combination with a roll such as A¹ of a roll
such as B¹ and a mandrel substantially as described.
6. The apparatus for rolling tubes substantially as described or illustrated in
Figures 1 and 2 or Figures 3 and 4 or Figures 5 and 6 of the accompanying
drawings.
Dated this 4th day of April 1898.