Improvements in the Method and Means of Drawing, Finishing, and Soldering Metal Tubes with Folded Joint.
Year: 1897

page_text: Date of Application, 23rd Mar., 1897-Accepted, 29th May, 1897
COMPLETE SPECIFICATION.
Improvements in the Method and Means of Drawing, Finishing, and
Soldering Metal Tubes with Folded Joint.
I, EUGEN JULIUS POST, of 6 Lichtstrasse, Cologne-Ehrenfeld in the Empire of
Germany, Manufacturer, 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 and means by which tubes can be drawn or
made from metal-bands or strips, the fold of which lies in the interior of the tubes
the outer fold-seam or joint being hardly visible.
In the annexed drawing, Sheet I, Fig. 1 illustrates this invention in a horizontal
longitudinal section with a tube in course of formation.
Figs. 2, 3, 4 and 5 are cross-sections on the lines z-z, y-y, x-x and w―w of
Fig. 1 respectively.
Fig. 6 shows a vertical section of the former without tube.
The device consists of the exterior former and the core. The first is composed of
the two halves a and b, which are kept together immovably at the sides by means of
the bars a, a or in any other convenient manner. In the under half a is provided a
semi-cylindrical or semi-conical hollow a², which diminishes correspondingly from the
rear-end to the front end. The upper half has a hollow b¹, the under part of which
coincides with the half-cylindrical hollow of the under half, but undergoes on its
upper part several changes of form in longitudinal direction. The upper part 2 of
the hollow beginning at the back end has a wedge-shaped-form with rectangular
cross-section, that is to say, its side-walls run together into a vertical line, whilst its
upper surface is horizontal (Fig. 6). The upper-part following this hollow 2 has
the cross-section shown in Fig. 4, and is therefore nearly circular, there being at a
convenient place in the periphery a channel and a corresponding swelling. This swelling
and channel has now the form shown in cross section in Fig. 3. This upper part
has also an inclined passage 63 for introducing a flat wire of hard solder h. Over the
leaving end of the opening 63 is provided a pressure-piece which provided with
sharp edge causes the proper introduction of the hard-solder-wire into the fold.
Behind the former there is also arranged a mouth-piece m serving for the
introduction of the metal-band used for producing the tube a having a conically
diminishing semi-cylindrical hollow m', there is provided in front of the former also
a socket which gives to the tube the exact cylindrical form..
The core operating together with the form diminishes equally from behind
forwardly and has on its back-part a nose d¹, corresponding to the hollow b² in the
form b and provided with wedge-shaped side-walls, and further forwards a recessed
channel 2 (Fig. 4) running into a lozenge-shaped hollow d³ (Fig. 3).
In the side of the nose d' of the core, Fig. 3, there is provided a groove d', which
runs into the edges of the channel d² (Fig. 4) and of the hollow d³ (Fig. 3).
Between the outer-wall of the core and the inner-wall of the hollow of the form
there must be a space equal to the thickness of the material.
The metal-band is bent first by the mouth-piece m (Fig. 1) and introduced into
the space between the core and the wall of the bollow of the form, whereby its one
edge lies against the groove d' (Fig. 5); by moving further forwards the metal-band
is guided with its edges always more together in consequence of the diminishing

page_text: form, so that the edges occupy first the position shown in Fig. 4 and are then
progressively conducted into the position shown in Fig. 3 by means of the channel
or groove provided in the form and in the core. With the progressive formation of
the fold the flat hard-solder-wire, which has been passed previously through a borax-
solution, is pulled forward correspondingly, so that it lies between the edges of the
fold, Fig. 5. After the tube has then also passed through the socket, the connection of
the longitudinal edges is ready, so that the tube has received the cross-section shown
in Fig. 2..
There remains only to show, how in the tubes produced in the before described
manner from metal-bands by folding the longitudinal edges the exterior folding-seams
are made so that they are hardly visible.
In the annexed drawing in Sheet II :
Fig. 1 shows the cross-section of a folded tube before finishing.
Fig. 2 shows it during finishing and Fig. 3 after finishing.
Figs. 4 and 5 show the cross-section of the drawing-core on lines - and y-y
of Fig. 6 whilst Fig. 6 shows the core in side-elevation.
Fig. 7 shows the cross-section of the drawing-tool, of the tube and of the
drawing-core during the pressing out of the nose.
Fig. 8 shows the cross-section of the drawing-tool, of the tube and of the
drawing-core during the pressing down of the nose and the closing of the
fold-seam.
Fig. 9 is a longitudinal section of the drawing-tools with a view of the tube over
the drawing-core and of the counter-bearing for the core.
From the tube a produced by the before described method by folding the
longitudinal edges of a metal band together, Fig. 1, a nose a¹ running parallelly with
the longitudinal seam is pressed out (Fig. 2). This pressing out is effected by a
corresponding projection d' provided on the core d (Fig. 6). The core has here the
cross-section shown in Fig. 5 and operates together with the correspondingly formed
drawing-tool (Fig. 7). Behind this projection the core receives the cross-section
shown in Fig. 4, where the groove d³ serves for receiving the fold. As the opening
is now completely circular in the drawing-tool, the nose a¹ is pressed down by the
latter and pressed against the second edge of the fold-seam enclosing the hand-solder-
wire in such a manner that the surfaces of the seam close extremely firmly against
one another and the exterior seam is hardly visible.
The openings in the drawing-tools have the longitudinal section shown in Fig. 9
that is to say they are enlarged conically at the ends in order to allow an easy
introduction and successive conducting from one form into the other. This working
can either follow directly the production of the tube or it can be made in a separate
operation.
The tubes provided with hard-solder-wire can then be soldered electrically or by
introducing them into a soldering-furnace.
Having now. particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what
I claim is:
1. An improved device for the production of tubes, in which the exterior form in
its under half is only provided with a conically diminishing semi-cylindrical hollow,
but the upper-half with an opening, which on its under part coincides with the
conically diminishing hollow of the under half, but is provided at the upper part first
with a hollow having a rectangular cross-section and provided with mutually
approaching side-walls, and then with an arch-like hollow, by which in co-operation
with the correspondingly formed cone and the longitudinal groove provided therein
the edges of the tube are folded inwards.
2. A process for rendering the outer fold-seam in tubes made of metal-bands by
means of folding hardly visible by pressing out next to the longitudinal seam a nose
and then pressing the same down again by the further working of the tube.

page_text: 3. In the production of tubes the introduction of a hard-solder-wire between the
edges of the fold in order to allow of hard-soldering by means of electricity or by
simply introducing them into a soldering furnace.
Dated this 23rd day of March 1897.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, Agents for Applicant.