Improvements in the Manufacture of Metal Tubes and in Apparatus therefor.
Year: 1889

page_text: Date of Application, 30th Sept., 1889-Accepted, 9th Nov., 1889
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Metal Tubes and in Apparatus
therefor.
A communication from abroad by WILHELM SCHROEDER, of Altena, in Westphalia,
Manufacturer, and PHIL BOECKER, Junr., of Hohenlimburg, of the Firm
Friedrich Boecker, Ph., Son & Co.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.L.M.E. of the Agency for Foreign
Patent Solicitors 6 Lord Street Liverpool and 6 Bank Street Manchester both in
the County of Lancaster and 323 High Holborn in the County of Middlesex, Civil
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 :-
The object of this invention is a process and apparatus for carrying it out, which
process differing from the hitherto known processes, provides for the rolling of
previously built up metal hollow shapes into tubes of any desired strength.
The processes hitherto in use for manufacturing pipes from hollow cast or bored
bars or blocks or for forming them by the use of weldable material, as sheet iron or
steel, consist, in the first case, in casting the bars or blocks over a core by means of
matrices, and in the latter case in that the iron or steel of the length required and
of requisite thickness and of a width corresponding to the circumference of the tubes
is bent together in such a manner that the edges of the sheets meet and overlap one
another obtusely or in the form of a wedge. This roughly made tube is then
placed in a welding furnace and welded together in a rolling mill, and further still
finishing in a boring machine must follow.
It is possible by this new process to produce not only tubes of any calibre or
strength, in doing which the material employed for the purpose does not undergo
the least alteration damaging to its strength, but also the expenditure of power
required to produce these tubes is considerably smaller than formerly.
For the production of tubes from weldablo metal, metal strips are placed in a
rolling mill and are then pressed together in the shape of a tube, see Figures 5, 6
and 7 of the drawings.
To aid the right arrangement of the separate strips which are intended to form
the hollow bodies, they can be placed round a core of wood or compressed coal or
even a tube piece of wrought iron, which latter welds itself therewith.
This tube thus put together is placed in a welding furnace and from there in a
rolling mill, in which it is fitted over a core which has an enlargement corresponding
to the calibre of the pipe required. This enlargement lies exactly at the point of
pressure of two adjustable rollers which are grooved to correspond to the outside
circumference of the tube. By these rollers and through a proper adjustment of the
same the tube is brought exactly to the size of the groove in the same, whereby it is
lengthened. Thereupon the tube is withdrawn from off the first core and fitted on a
second one the enlargement of which is chosen according to requirement, which must
however be as much longer as the tube has extended, it being now again exposed to
a second rolling with grooved rollers, the grooves of which have a sinaller diameter
than those in the first set. Through the adjustment of the rollers and the backwards
and forwards rolling the tube is then brought to the size of the following narrower
grooved rollers, whereby it is again lengthened at both ends. In this fashion the
tube is fitted on a core of constantly increasing length and subjected to the action of
several rollers with grooves of decreasing calibres.
The backwards and forwards rolling is continued up to the point when the core,
in consequence of its increasing length, no longer possesses the required rigidity.
When this point is reached pressure will only be given for rolling out the pipes
when the above mentioned cores are directed in the forward direction.

page_text: This process is continued until the required thinness of the tube sides is
attained.
If, owing to the material used (for instance in the case of unweldable metal) or in
view of the purpose of the finished article, it is desired to abolish the building up of
the pipe, hollow cast or previously bored rods or blocks are submitted to the above
described process, using a heating furnace instead of a welding one.
The rolling mill used in carrying out this process, is represented on the annexed
drawing, and in Figures 1, 2, and 3, it is shown in side, top and back view.
Figure is a section of the slide carrying the cores, and Figures 5, 6 and 7 represent.
the formation of tubes of weldable inaterial.
In the mill frame the rolls W W₁ are placed in such a manner that the lower
roller W may be adjusted upwards equally as much as the upper roller W is moved
downwards for the purpose of reducing the calibre, by the pressure spindle a.
The
adjustment of the rollers is carried out in the usual manner by means of the hand
wheels A B, and the spindle carrying the pinion C, the bevel gearing D and
wedge E.
The rollers W W are provided with grooves of various sizes (Figure 2) and
between each pair of equal grooves of the rollers lies a core bar F with an enlargement
of the requisite size. The core bars F, which are of a constantly increasing length,
are fastened to the bridge G by screw lock nuts, so that by adjusting the screws a
certain length can be given to the core bars.. The bridge G is movable horizontally
and is for this purpose fitted with slides J which rest in the grooves K arranged in
the mill frame. The spindles L are screwed through the slides J, so that by the
simultaneous turning of these spindles the bridge G and with it the core bars F
be moved backwards or forwards. For actuating the spindles the hand wheels N are
provided, situated on their ends, both of which wheels engage with the spur-wheel M.
The spur-wheel M is fixed on the driving axle, and the latter carries a fixed pulley Q
and two loose pulleys P P, of which one is driven by an open and the other by a
crossed belt. According to whether the straight or crossed belt is transferred from
the loose pulloy to the fixed one, the axles revolve to the right or left and move
correspondingly the bridge G and the core bars F in one or..the other direction.
Further the bridge G rests on a carriage R which can be pushed backwards and
forwards on four wheels, Figure 1; and is provided at the front with a stage S
through which the core bars pass, and on the other hand at the back with a
hand rail.
The mode of action is as follows:-
may
After the tube built up of rolled strips (Figures 5, 6, and 7) is taken out of the
welding furnace, it is first fitted onto core bar F1 (Figure 2). For this purpose
the bridge G is brought by means of the adjustable belt driving arrangement PQP
to such a distance from the rollers W W₁ that the thick part H of the core rests in
the centre of the rollers W W. The height of the core is such that it lies in the
middle of the hollow formed by the upper and lower rollers. The article to be
rolled out comes first from the side X onto the core bar I and receives the first squeeze
as it is gradually forced by the rollers over the thick part of the core bar, and
therefore always directly in the direction of the rolls pressed onto the thick part of
the core on the other hand, after passing this pressure point, the hinder part of the
core-bar fits loosely. When the tube piece fitted on the core bar I reaches the
bridge S of the carriage R, the rolls are reversed and the tube, by aid of
the carriage R which one or more workmen at T or U U manipulate, is pushed again
between the rollers and comes out again at the side X. The core bar F is not moved
during this operation as the bridge G remains in one position, the carriage alone
beneath the same being pushed forward, and by means of the stage S the tube fitted
on the core is pushed in front of and under the rollers. The back and forward
rolling, together with the necessary turning of the tube by means of the thickening
of the core and the requisite arrangement of the two rollers, is repeated on the
first core bar as often as the length of the core bar or the diminution of the thickness
of the tube wall's permits. Thereupon the following core bars are utilized the bridge

page_text: being pushed back each time to suit the length of the core bar. If the rolled out
tube has reached such a length that the corresponding core bar no longer can oppose
the necessary rigidity to the pressure of the rollers, the pressure is given by the
rollers only when they are travelling in the direction of X Y. The thick part H of
the core bar F, that is the working part of the same, are made to correspond with
the bore of tube required.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, 1 declare that what I claim is :-
1. A process for the manufacture of metal tubes wherein the hollow blank
employed (which is preferably built up of longitudinal strips welded together to form
a tube) is removed from a heating or welding furnace to the rolling mill where it is
rolled out by means of rollers with grooves diminishing in size to the required
extent over successive core bars of increasing length each having an enlargement
corresponding to the required bore of the tube, substantially as described.
2. A rolling mill for the manufacture of metal tubes having a pair of rolls W W'
provided with a series of grooves constantly diminishing in size and a row of core
bars F between these rollers which are each provided with an enlargement H each
of which however is longer than the previous one, the ends of the said core bars F
being fastened to a bridge G movable in the direction of the rolls, substantially as
and for the purposes set forth.
3. In a rolling apparatus such as described, a carriage R having a stage S through
which the cores F pass whereby the tube under treatment may be readily fed back
under the rolls WW1 on their reverse movement, substantially as described and
shown.
Dated this 28th day of September 1880
WM. P. THOMPSON & Co.,
Agents for the Applicant.