Note: Descriptions are shown in the official language in which they were submitted.
103903~i
This invention relates gen~rally to an improved appar-
atus for forming integral necks on metal walls, particularly on
hollow, metallic articles.
It is known in the prior art to form coupling flanges
and the like on hollow metallic articles, such as tubes and con-
tainers, by heating the area thereof about a surface opening pro-
vided therein to soften the metal of the article, and then moving
an extruding tool by means of a suita~le transport device out-
wardly through the opening from the interior space of the hollow -
article. The tool bends the edges of the article opening out-
wardly to form a neck or flange which can be welded or otherwise
coupled to pipes, conduits and the like.
As stated above, it is necessary to heat the region
about the metallic article opening in order to soften the article
metal and enable shaping of the neck with the extruding tool.
Prior art methods and apparatus which have been used to form necks
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on thin-walled hollow articles have not generally been able to
maintain the temperature of the article region about the opening
at a level suitable for shaping throughout the entire neck form-
ing operation. rrhus~ a large amount of energy is expended in
' shaping the neck by means of such methods and apparatus.
~' According to the present invention there is provided
apparatus for forming an integral neck on a metal wall, about an
; opening therein, said apparatus comprising an extruding tool of
.,
the type adapted to be drawn through the opening with an outer
surface of the tool engaging the metal wall around the opening so
as to form the neck therefrom, the extruding tool comprising an
inner support element, said outer surface and means for impeding
thermal conduction between said outer surface and the inner sup-
port element.
The tool is preferably used in conjunction with a gas
burner means which comprises a first curved gas burner having
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downwardly directed nozzles which heat the region o~ the wall
about the opening thereof prior to formation of the neck, and a
second curved gas burner having outwardly directed nozzles which
heat the neck formed by the tool as it is moved through the
article opening.
The extruding tool may include a surface layer disposed
on the inner support element and fabricated of non-scaling sheet
metal having a low thermal conduction characteristic, and an
intermediate support means, which may comprise a plurality of
support members such as wires, or thermal insulation material,
interposed between the support element and surface layer for
supporting and thermally insulating the surface layer on the
; inner support element. Alternatively the extruding tool may com-
prise the inner support element and an outer surface layer of
ceramic material, or an inner support element having surface
grooves which diminish the support area for the surface layer.
- The outer surface is preferably conical in shape.
In prior art methods, the metallic article is generally
preheated in a heating apparatus before utilization of the extrud-
ing tool and formatiom of the neck. In contrast, it is now pro-
posed that the article be continuously heated by gas burner means
which are adapted to adjust to the shape of the article about the
surface opening thereof, so that the article is heated also dur-
ing formation of the neck to compensate for heat losses in the
article and through the extruding tool, which cannot be ideally
thermally insulated. With this method and the apparatus of the
present invention, the time required to carry out the neck form-
ing process is reduced; the quality of the article neck formed is
increased; the structure of the metal of the article is not dam-
aged; and the previously required, time consuming annealing pro-
cess is eliminated.
In the accompanying drawings which illustrate exemplary
embodiments of the present invention:
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Figure 1 is a perspective view of a hollow, metallic
article and part of a neck forming apparatus, prior to formation
of the article neck;
Figure 2 is an exploded pexspective view of the article
. and a neck forming apparatus, subsequent to the formation of the
article neck;
Figure 3 is a perspective view of alternative embodi- -
ments of an extruding tool inner support element;
Figure 4 is a side view, partly in cross-section, of
.~ 10 another embodiment of an extruding tool,
: Figure 5 is a side view, partly in cross-section, of
still another embodiment of an extruding tool;
Figure 6 is a top view of still a further embodiment of
an extruding tool; and
Figure 7 is a side view of the tool illustrated in
Figure 6. ;
Referring now to the drawings, in particular to Figures
1 and 2, there is shown a hollow, metallic article, illustrated
as cylinder 1 having radial end flanges 2, in which an elliptical
20 shaped surface opening 3, about which the neck is formed, is dis~
posed. Gas burner means, illustrated as curved gas burners 4,
are disposed about the opening and are movable to and from the ~`
region thereof. The burner means heats the metal of the article -~
about the surface opening to a temperature which renders it soft ~:
enough to be shaped. Gas burners 4 are preferably semi-ellipt-
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ical in shape and include downwardly directed nozzles for
:~. directing the gas flames thereof towards the surface of cylinder
1 about opening 3. Supply pipes 5 transport a burnable gas mix-
ture to the burners and function as a handle for moving the
burners to and from the region of opening 3. The dimensions of
the gas burners 4 are preferably such that approximately one half
~-~ of the peripheral area on each side of opening 3 is covered by
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each burner. It should also be noted that opening 3 has not
been illustrated in Figure 1 in its original elliptical shape,
but rather is shown partly reshaped as a result of the heating of
the cylinder by the gas burners. ~ -
An extruding tool is shown in Figure 2, and comprises
an inner support element, generally designated 13, a surface layer
15 fabricated of non-scaling sheet me~al having a low thermal con-
duction characteristic disposed on element 13, and intermediate
support means 14, illustrated in Figure 2 as a plurality of cir-
cular wires interconnected in a basket configuration, interposedbetween element 13 and surface layer 15 for supporting and
thermally insulating the surface layer on support element 13~
The dimensions of the inner support element 13, surface layer 15,
and the wire basket are matched so that linear contact between
wires 18, element 13 and surface layer 15 is assured. The air
spaces between the wires of the basket thermally insulate element
13 fr~m surface layer 15 and inhibit the flow of heat from layer
~ 15 to the inner support element, thereby reducing heat loss dur- ;-
! ing formation of the neck. The main body portion 16 of elemen~
; 20 13 is conical in shape and wires 18 are prefera~ly arranged
thereon so as to extend along the lines thereof of steepest
gradient.
Element 13 further includes a neck forming portion 17
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at the lower end thereof which, in the illustrated embodiment of
the invention, is cylindrical in shape. The upper end thereof
; includes a coupling member 12 which is connected to a suitable
device, such as a hydraulic puller, which moves the extruding
tool through opening 3 outwardly from the interior space of
cylinder 1, for forming the neck 7 thereabout. Since such devices
are known in the art, they are not described in detail herein.
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~W9036
Second curved gas burners 11, only one o which is
illustrated in Figure 2, are provided for heating the flange 7 as
it is formed by the extruding tool. surner 10 includes a gas
mixture supply pipe 11 which functions in the same manner as
supply pipes 5 of burners 4, and is cylindrical in shape to
correspond to that of the flange. Burner 10 includes nozzles
which are outwardly directed towards flange 7 for heating the ~`
latter continuously during formation thereof at a temperature
which renders the metal of cylinder 1 suitably soft for shaping.
It should be noted that burners 10 are shaped differently from
burners 4 since opening 3 is shaped in the form of a bulging
ellipse and the flange to be formed is circular in shape. The
direction of the nozzles, and their disposition with respect to
the center of opening 3, must be varied to ensure proper heating
of the article.
The burners may be rendered movable with respect to
the article opening by mounting them on displaceable, pivotable
slides which are movable by means of automatic or manual controls.
i The supply of the burnable gas
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mixture to the burners is regulated as necessary by a manual control, and
preferably with the use of temper~ture sensors so that a suitable temperature
range of the metal of the article is maintained.
; Instead of the wire basket illustrated in Figure 2, the intermedi-
' ate support means may comprise merely a plurality of support members, for ex-
ample, a plurality of circular wires, disposed on support element 13, along
the steepest gradient lines of portion 16 thereof. Even if a large number of
such support elements are used, the total area of the surface layer is much
greater than the area of the surface layer which engages the support elements,
and heat transfer between element 13 and surface layer 15 is effectively in-
hibited.
Figures 3-7 il-ustrate alternative embodiments of the extruding
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!~ tool of the apparatus. In Figure 3, inner support element 13 is provided
with a plurality of spaced apart surface grooves which form a support surface
for surface layer lS. Those portions of element 13 between the grooves en-
gage surface layer 15 when it is disposed thereon and provide a support sur-
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i face which is diminished in area with respect to the total surface area of
element 13. Heat transfer between the inner support element and surface
i layer is thereby effectively inhibited. The surface grooves may be longit-
udinal grooves 21 which extend axially along the lines of steepest gradient
of element 137 or, alternatively, circumferential grooves 22 which e~tend
around element 13. Moreover, both types of grooves may be utilized on the
same support element to provide the re~uired support surface~ if desired.
¦ As illustrated in Figure 4, the intermediate support means may com-
prise a layer of thermal insulation material 23, such as, for example, mineral
wool, or a combination of mineral and organic materials. The mass of mat-
erial fills the space between the e~ement 13 and surface layer 15 and thereby
inhibits heat transfer between the two. The separate surface layer shell and
intermediate support means may also be dispensed with and a unitary extruding
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tool constructed by coating the surface of element 13 with a sur-
face layer of ceramic material 25, as shown in Figure 5. Because
the layer of ceramic material is thin it stores little heat.
The extruding tools illustrated in and described with
reference to Figures 2-5 include an inner support element which
is conical in shape~ As a result, it happens that the upper
portion of the tool which is first moved through article opening
3 when forming flange 7 engages cylinder l about opening 3 only
at separate points. The upper portion 27 of the extruding tool
6 illustrated in Figures 6 and 7, however, is elliptical in shape,
corresponding to that of opening 3, so that the upper portion of
the extruding tool engages the entire periphery of opening 3 as
it is moved therethrough. This assures that the metal of the
article is uniformly stressed during formation of the flange.
The lower portion 28 of the tool is, of course, cylindrical in
shape as previously described. It is also preferable if the tool
is shaped so that its surface 30 is in the form of a tractrix
curve. This results in a particularly favorable application of
the applied forces produced by the tool.
Although burners 4 and lO have been illustrated as
being the segment type, it should be noted that other type burners
may be utilized, such as burners with adjustable nozzles which
can direct the gas flames thereof both downwardly and outwardly.
Also, different size segment burners, covering other than half
of the periphery about the article opening or flange, may also
be utilized. Movement of the burners may be attained by guide
;~ tubes, rollers, or the like, either manually, or automaticallywith respect to metal temperature and position of the extruding
tool.
To produce a neck, burners 4 are first moved to the
position illustrated in Figure l about opening 3 and heat the
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1039036
region there to a temperature sufficient to soften the metal of
cylinder 2 and thereby render it suitable for shaping. The
; extruding tool 6 is then moved from the inerior space of cylinder
2 outwardly through opening 3. As soon as the edge of opening 3
begins to bulge outwardly, burners 4 are retracted and are re-
placed by burners 10 which continue to heat the neck 7 being
formed as the extruding tool continues to move at the temperature
suited for shaping of the cylinder metal. sy means of this con-
tinuous heating of the cylinder about opening 3, the temperature
of the metal is maintained relatively constant during the entire
shaping process. When the extruding tool has been moved com-
pletely through opening 3, burners 10 are removed and neck 7 is
permitted to cool. A subsequent annealing of the neck after
formation is not needed due to the fact that the metal of the
article shaped is maintained at a temperature suitable for its
shaping throughout formation of the neck.
In the foregoing specification, the invention has been
descxibed with reference to specific exemplary embodiments there-
of. It will, however, be evident, that various modifications
and changes may be made thereunto without departing from the
broader spirit and scope of the invention as set forth in the
appended claims. The specification and drawings are, accordingly,
to be regarded in an illustrative rather than in a restrictive
Il sense.
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