Improvements in the Manufacture of Tapered Tubes or Tubes of any Desired Profile.
Year: 1897

page_text: Date of Application, 10th Feb., 1897-Accepted, 5th Feb., 1898
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Tapered Tubes or Tubes of
any Desired Profile.
I, FRANZ JOSEF SEYFRIED, of Mülheim on the Rhine, in the Empire of Germany,
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:-
By an older process, tapered tubes and tubes of any desired longitudinal profile
were made by compressing, across or transverse to its previous direction of rolling, a
block of equal width throughout its entire length and provided with one or more
holes corresponding to the desired longitudinal profile of the tube, that is to say the
blocks were compressed across the longitudinal direction of the holes therein in such
a way that the holes as such were closed by the flattening and the facing sides of the
holes lay pressed evenly and firmly one upon the other. This body was then drawn
out longitudinally by being passed through rolls which did not allow it to expand
laterally until the resulting new body reached the full length of the tube to be
produced. This new body usually called a "double strip" had a uniform width along
its entire length and when the crude or initial block had only a single tapering hole,
the said double strip required to be cut parallel to the two lateral straight or curved
converging edges or border lines of the block hole which was compressed into one
plane. If the crude block had several holes the double strip produced had to be cut
apart at the centre between the usually parallel lateral border edges facing one
another of the flat pressed block holes. This cutting out and cutting apart of the
rolled out double strip very considerably increased the costs of manufacture, because
the strips were always so heavy and thick that they could only be expanded by
suitably strong machinery.
In order to overcome these drawbacks without losing any of the advantages of the
process of manufacture, the improved process hereinafter described has been devised
in which the hollow block which is to be rolled into a tube has only one hole, whilst
its two vertical side faces extend parallel or nearly parallel to the lateral border lines
of the hole in the block. The support of the wedge shaped or otherwise profiled
block (which support is absolutely necessary for producing a saleable tube) is obtained
by means of wedges or shaping pieces which usually and preferably make up this
block to a body of equal width along its entire length. Both the perforated or hollow
block and the wedges or shaping-pieces (which latter in order to further cheapen the
process may also consist of hollow blocks which are to be rolled into tubes) are rolled
together between rolls into a double strip of usually uniform total width, which on
completion of the operation of rolling can be easily again separated into the original
separate pieces.
This improved process will now be described with reference to the accompanying
drawings, in which,
Figure 1 is a side view; and
Figure 2 an end view of a hollow block employed for forming a simple tapering
tube provided with two longitudinal ridges or fins, as is shown in Figure 6 in a side
~ and triceune 7 in cross section

page_text: The external surfaces a b of the hollow block opposite one another run parallel or
approximately parallel to the internal lines or surfaces ef of the hole in the hollow
block. This hollow block is built up by means of wedge pieces i, Figure 3, to a
body of equal width and equal height at both ends, either after it has been compressed
in the direction of arrows h, (Figure 2) until the hole closes, or in its initial condition
(Figure 1).
Figure 4 is a plan view and Figure 5 a cross section of the double strip formed by
rolling out the prism, formed in the manner just stated, in a suitable rolling mill or
the like which gives the double strip an unyielding lateral guidance, and during this
rolling out the wedge pieces i in combination with the unyielding lateral guidance
-given them, prevent the sides ab and the edges ef of the hole g of the block from
- diverging from a straight line. Without the wedges i, the side surfaces a band edges ef
in most cases would diverge very considerably from a straight line in such a way that
use of the tube produced would evidently be impossible.
After the removal, which is easily and simply effected, of the loose although firmly
pressed on wedges lying against the double strip, the tube may be widened or
opened out in any known and suitable manner so that it assumes the form shown in
Figures 6 and 7. If desired the ridges or finsk, Figure 7, may also be rolled down
and thereby smooth tapering tubes be produced.
If the height H, Figure 2, of the block be greater at one side than at the other,
the result will be that the block will be more strongly rolled at the thicker side and
consequently also the taper of the tube will be less at the places which correspond to
the thicker parts than at the thinner. Of course the centre of the block may be
made the thickest in order to have at this point the least and at the ends the greatest
taper..
In tubes in which the ribs or finsk are retained it is preferable to make these
broader at the lower than at the upper end, as, for instance, where these tubes are
.used for telegraph poles in which the greatest strain comes on this lower end. In
order to attain this object in carrying out this process the sides bordered by the
lines a e and fb (Figure 1) are made thicker at the broader end of the block. In
this case a e and bf respectively no longer run parallel but converge towards the
narrow end of the double strip. As however the clear diameter of the tube to be
produced is dependent on the mutual distance between the lines or edges e and f the
ribs or fins during the widening of the double strip into a tube will remain entirely
by themselves broader at the lower end of the tube than at the upper.
It is not absolutely necessary to make the hollow block symmetrical to its longitu-
dinal axis, as presumed in Figure 1. It may for instance be made quite one sided
by the surfaces a and e running vertically whilst the corresponding opposite side b
and the inner surface or edge frun obliquely. It is only necessary then to use a
wedge-shaped shaping-piece i of such a form that the then formed body has parallel
side surfaces ab which is always a condition when the width e f of the hole in the
block is to be equal to half the corresponding periphery which the tube to be made
shall have. It is also not absolutely necessary that the initial hollow block after its
formation by casting or hammering shall have both its ends made of exactly the
thickness which corresponds to the similarly placed masses of the double strip to be
produced (see for instance Figures 4 and 5). On the contrary a quite similar hollow
block may be used for tubes of varying taper and by simultaneous compression with
wedge pieces (Figures 8 and 9) of suitable dimensions at both ends there may be
given to it, along its entire length, the width necessary for producing the desired
tapered tube.
In order to cheapen the manufacture of the tubes the parts i may be
enlarged and assume the form of hollow blocks which are then also rolled out into
double strips and are later on widened out to produce a tubular form.
The process hereinbefore described may also be employed for producing tubes or
tubular bodies which are not uniformly tapering but are shaped otherwise, for
instance in longitudinally interrupted or wavy lines. Figures 10-17 show examples
'for the making of such tubes.
Figure 13 is a side view of a ridged or ribbed
tube not symmetrical with its

page_text: longitudinal axis. In order to make this, the previously perforated block (Figure 10),
which in order to simplify the process may have the simple initial form shown in
Figure 1, is compressed in combination with a wedge piece in such a way that the
form shown in Figure 11 is produced. The composite body shown in Figure 11 is
then rolled out into a double strip and the form shown in Figure 12 is obtained.
After the removal of the wedge or shaping piece 2 the double strip is expanded and
then assumes the tubular form shown in Figure 13. The ridges are again marked k.
From the foregoing it is evident without further explanation that a tube symmetrical
to its longitudinal axis but of varying taper can be produced by pressing from each
side a wedge piece into the hollow block Figure 10.
The wedge pieces 22 must of course not be as highly heated as the hollow block
because otherwise they could not alter the shape of the latter to suit their own.
Figure 17 shows a tube made in a similar manner to that shown in Figure 13.
Suitably shaped and less highly heated shaping pieces 23 are placed (see Figure 14)
on both sides of a perforated block which may be for instance of the initial form
shown in Figure 1, and are pressed by rolling or hammering into such block so that
the composite body shown in horizontal section in Figure 15, of preferably uniform
outer width results, which body is then rolled out in the manner hereinbefore
described so that after the removal of the shaping pieces 3 which extend exactly to
the same extent as the block itself, a double strip, Figure 16, remains.
After this double strip has been expanded or widened out for instance by gas
pressure when in a red hot condition, it yields a tube with two longitudinal ribs or
fins as shown in Figure 17.
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
clain is :-
The process of manufacturing tapering or suitably profiled tubes by rolling out
hollow blocks into hollow strips, and a successive widening of these strips,
characterised by the hollow blocks being made externally and internally tapered, or
roughly shaped or profiled, and being then rolled out in combination with one or
more shaping pieces, or one or more other hollow blocks, directly into externally and
internally tapered or suitably profiled double strips with a view to the said double
strips being further widened out to externally and internally tapered or suitably
profiled tubes, substantially as hereinbefore set forth.
Dated this 9th day of
100
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.