Note: Descriptions are shown in the official language in which they were submitted.
CA 02491358 2004-12-30
Translation of PCTIEP20031005350
Attorney Docket: fl95309.55734US
Method and Ayparatus for Fastening- Components to Initially Closed Hollow
Profiles
The invention relates to a method for fastening components to initially closed
hollow
profiles, according to the preamble of claim 1, and a device for that purpose
according to the preamble of claim 15.
A method of this class, as well as a device of this class, is known from DE
196 19
626 C2. In it hangers are affixed to a hollow profile such that both the
hanger and
the hollow profile are placed in engravings of a high internal pressure
forming tool
and then the section is subjected to a high internal fluid pressure. Under
this
pressure the material of the hollow profile flows radially outward and at the
location of
the hanger it flows conformingly around the surface of the latter which has an
undercut shape so that an interlocking bond is established between the hanger
and
the hollow profile. The described fastening of the hanger to the hollow
profile is
possible, however, only within the expanded area between the axial sealing,
punches
that close the ends of the hollow profile. Furthermore, the flexibility of the
method is
limited by the fact that the shape of the high internal pressure forming tool
permanently establishes the shape and location of the bond, so that in the
case of
different requirements as to the position and kind of the interlocking bond
different
tools are necessary. The result is great expense and investment in the device.
The invention is addressed to the task of improving a method of that kind and
a
device also of that kind so that a secure fastening of the component to the
hollow
profile is made possible in a simple manner, regardless of the point of
fastening.
The problem is solved according to the invention by the features of claim 1
with
regard to the method and by the features of claim 15 in regard to the device.
inasmuch as an external pressure is applied to the adjacent walls of the
hollow
profile and hanger by means of a pressure medium and thus they are forced
inward
into the interior of the hollow profile thus forming a double-walled
inden#ation, a
clamping of the walls is achieved which assures a secure fastening of the
hanger to
the hollow profile. This indentation is possible axially and radially at any
point on the
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Translation of PCT/EP20031005350
Attorney Docket: 095309.55734US
hollow profile and is freed of any specific shapes of the receiver of the
hollow profile
and hanger, so that not only the receiver but also the entire device can be
configured
in a very simple manner. With the method of the invention a simple possibility
of
fastening is offered that is reliable and practical for hollow profiles that
are to be
fastened together, which otherwise can not be fastened together in a reliable
manner, especially hollow profiles shaped by internal high pressure with
attachments
or in some cases to other hollow profiles made in the same manner.
Appropriate developments of the invention can be found in the sub-claims;
otherwise
the invention is further explained below with the aid of several embodiments
represented in the drawings, wherein:
Figure 1 is a lateral longitudinal fragmentary section of a device of the
invention with
a plunger introduced into a hollow profile and having a punch which can be
inserted
from the exterior and can run on the wails of a hollow profile and component.
Figure 2 is a fragmentary cross section of the device of Figure 1 with the
plunger in
the piercing position with a mandrel of undercut shape.
Figure 3 shows an expandable plunger of a device according to the invention in
a
lateral longitudinal cross section.
Figure 4 shows a device according to the invention in a lateral longitudinal
cross
section with a plunger in the piercing phase and with a mandrel from Figure 3
spread
out in the piercing position.
Figure 5 shows in a lateral longitudinal section a device according to the
invention
with a bipartite mandrel and a fluid pressure medium for the inward forcing.
Figure 6 shows in a lateral longitudinal section a device according to the
invention
with a bipartite mandrel with pinching action on the material of the wails to
be joined.
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Translation of PCTIEP20031005350
Attorney Docket: 095309.55734US
Figure 7 shows in a lateral longitudinal section a device according to the
invention
with an elastic skin introduced into the hollow profile.
In Figure 1 there is shown a device for fastening a component 2 to an
initially closed
hollow profile 3. The hollow profile 3 and the component 2 are held in a
receiver here
not further shown, with their walls 4 and 5 placed against one another. In
this case it
is desirable for the assembly process and for a simplified configuration of
the
receiver if the wall 5 of the component 2 is matched to the contours of the
wall 4 of
the hollow profile 3. The wall 5 of the flat component 2 is here formed by a
flange
projecting at right angles. For assembly, a metal mandrel 6 of the device 1 is
inserted into the hollow profile 3 and on the circumference of the mandrel a
gap 7
open in the direction of insertion is formed. The axial opening of the gap 7
assures
the easy withdrawal of the mandrel 6 after the assembly is completed. This gap
7
comes to rest at the location of the walls 4 and 5 which are to be assembled.
Then a
plunger 8 forming the pressure medium arranged according to the invention
locally
outside of the hollow profile 3, opposite the gap 7, is driven by a hydraulic,
pneumatic, electric motor, electromagnetic or mechanical drive connected to
the
back of the plunger 8 in the direction of the arrow directly against the wall
5 and
indirectly against the adjacent wall 4. As the movement continues, the massive
cylindrical plunger 8 pushes the walls 4 and 5 into the gap 7, which thereby
forms a
molded image of the mandrel 6 serving as a die.
Although in this case a certain interlocking clamping together of the walls 4
and 5 is
achieved, it is desirable if the walls 4 and 5 are forced by the plunger 8
into the gap 7
such that they are forced against the wall 9 of the gap in order to improve
the
clamping in the manner of a press fit (Fig. 2) and in addition #o the shape
interlock to
achieve a friction lock which holds the walls 4 and 5 securely, i.e., for
release with
difficulty, against one another. In this case the wall of the hollow profile 3
that is
nearest the gap conforms to the shape of the gap wall 9. The double-walled
indentation 10 formed by the pressing action can have substantially straight
mantle
lines. The gap 7, however, can also be formed with undercut surfaces,
especially in
the manner of a dovetail 11. Thus, on account of the counterpressure exercised
by
the gap wall 9 outwardly from the interior 12 of the hollow profile 3,
undercuts 13 and
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Attorney Docket: 095309.55734US
14 are formed on the walls 4 and 5 by the forcing in and compression of the
walls 4
and 5 into the gap 7. For that reason the walls 5 of component 2 are anchored
against radial removal in the wall 4 of the hollow profile. In the present
embodiment
the component 2 is fastened with its wall 5 outside on the hollow profile wall
4.
However, it is also possible within the scope of the invention in the same way
to
position the wall 5 of component 2 inside of the hollow profile 3 and fasten
it on the
inside of its wall 4. The mandrel 6 must then only be reduced in its diameter.
With
the above variant it is possible in a simple manner to fasten the component 2
also to
the circumference of the ends of the hollow profile 3 - including, in the
extreme case,
the outer edge of the hollow profile 3 - which is not possible or possibly
only with
difficulty with the method described in the cited state of the art. It is
furthermore
conceivable, instead of the cylindrical shape of the plunger 8 to use a
plunger
configuration in which the tip of the plunger penetrating into the interior 12
of the
hollow profile 3 is of spatulate shape. if the plunger 8 is now forced with
the walls 4
and 5 into the gap 7, the walls do not entirely fill out the shape of the gap
7 with the
plunger 8 in its axial end position. By rotating the plunger 8 by 90 degrees
the wall
material of walls 4 and 5 is forced into the gap 7 such that it is completely
filled up
and the walls 4 and 5 are made to conform to the shape of the gap. Then the
plunger 8 is turned back 90 degrees and can then be easily removed from the
gap 7
and the indentation 10 in the wall. Due to the complete conformity of the
walls 4, 5 in
the gap 7 the desired undercut is optimally shaped to match it, so that the
clamping
together of the walls 4 and 5 is improved and thus their lock onto one another
is
improved.
In another embodiment according to Figures 3 and 4, a variant of the invention
that is
advantageous due to their simple configuration is illustrated. The receiver in
this
case forms a high internal pressure forming tool 15 into which one or more
plungers
8 spaced axially apart from one another are integrated, which are displaceable
in
guides 16 as indicated by the vertical double arrow. It is indeed conceivable
for the
plunger 8 to force the walls 4 and 5 into the interior 12 of the hollow
profile 3, operate
against atmospheric pressure in the hollow profile 3, after which a high
fluidic internal
pressure is created (Fig. 4, I).
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It is a more economic process and shortens the cycling time, however, if the
hollow
profile 3 is under high internal pressure while the plunger 8 is forcing the
walls 4 and
inward. The counter pressure which would be created in the foregoing example
against the plunger 8 and the walls 4 and 5 by contact with the notch wall 9
for the
forming operation is here provided by the high internal pressure. On account
of the
forces of the internal high pressure and the plunger 8 acting on the face 17
of the
indentation, a sideways displacement of the material of the hollow profile and
component, rendered fluid by the high internal pressure, takes place. The end
face
17 is made thinner as a result, leading to an accumulation of the hollow
profile and
component material in the edge area 18 of the end face 17. This has the effect
that
all around in this area 18 undercut areas form in the indentation 10, so that,
in a
manner improved beyond the preceding embodiment, the result is a junction
similar
to a through-joint, which is inseparable in any direction (axial and radial).
A more intense formation of the undercut surfaces is achieved by using a
plunger 8
according to Figure 3, which can be spread open at its end 19 facing the
hollow
profile. This end has a central axial bore 20 which tapers toward the end 19
facing
the hollow profile and ends there. Depending on the elasticity of its material
in the
area of the taper, the plunger 8 is provided at a place on its circumference
with an
axial slot 21 to provide for the outward expansion of the end 19, which scores
the
bore 20 over its entire length. in the bore 20 a pin 22 is guided for the
displacement
indicated by the double arrow; the pin 22 has at its bottom end 23 wedging
surfaces
24 by means of which, when it is driven downwardly through the taper in the
bore 20,
it comes in contact with the bore walls and drives apart the slotted sectors
of the end
19. In this manner, as indicated by the two arrows, when the plunger 8 reaches
the
end in the area of the face 27, both the hollow profile and the material of
the
indentation 10 are forced radially apart causing the undercut surfaces to be
enlarged
(Fig. 4, II). In this way the match between the walls 4 and 5 and thus their
mating
with one another is improved. After the desired undercut's formation has been
achieved, the pin 22 is withdrawn, after which the end 19 returns by its
elasticity to its
starting position, so that the plunger 8 can be removed from the indentation
10.
In an alternative to the two embodiments described, in the case where the
receiver is
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Attorney Docket: 095309.55734US
in the form of a high internal pressure shaping tool 15, a mandrel 6 can be
driven into
the hollow profile 3. In this case the mandrel 6, in a dual function, can
advantageously form both the matrix for the plunger 8 and the axial sealing
plunger
of the tool 15.
It has been assumed up to now that the forcing means is the plunger 8. In
another
embodiment the forcing means, however, can also be a fluid pressure column 25,
as
seen, for example, in Figure 5. For this purpose a passage 27 is formed in the
receiver, which in this case is likewise an internal high pressure forming
tool 26, and
is connected outside of the receiver to a pressure generator, and terminates
at the
walls 4 and 5 in the receiver. The passage 27 is sealed in the marginal area
28 of
the receiver by at least one sealing ring 30 beside its opening 29. The
pressure
column 25 causes virtually no wear on the device 1 and has the additional
advantage
that the pressure on the walls 4 and 5 can be adjusted very finely and quickly
and
can be continually adapted to the desired sequence of the pressure injection
process.
In the present embodiment according to Figure 5, a mandrel 31 is introduced
with
little free play into the hollow profile 3. In order to form undercut surtaces
all the way
around the edge 19 of the end face 17 in the indentation, the recess 32 of the
mandrel 31 is trough-shaped - i.e., continuous ail around - with a dovetail-
like cross
section. With the pressure column 25 the walls 4 and 5 are forced into the
recess 32
until they contact the wall 33 of the recess. The flexibility of the hydraulic
fluid is an
advantage to the accurate mating of the walls 4 and 5 with the shape of the
indentation, because in contrast to the limited ability of a rigidly shaped
plunger, it is
able to follow the progress of the impression in all directions. The pressure
is
applied, therefore, directly by the driven hydraulic fluid.
After the shaping of the indentation 10, in order to remove the mandrel 31
frflm the
forming tool 26 with the release of the undercut surfaces, the mandrel 31 is
divided
into two parts 34 and 35 along its length. Each part 34 and 35 has a section
of the
recess 32 which is formed at the face 36 of each part 34 and 35, so that when
the
two ends 36 are in contact with one another the whole recess 32 is the result.
To
assure that the two parts 34 and 35 will be together during the impressing
process it
is desirable to screw the two parts 34 and 35 together. After the indentation
10 has
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Attorney Docket: 095309.55734US
been completed, the screw fastening is released and the two parts 34 and 35
are
drawn in opposite directions out of the hollow profile 3 and the forming tool
26.
Alternatively, parts 34 and 35 can be driven by hydraulic cylinders and held
securely
in the end position within the hollow profile 3. This certainly shortens the
cycle in
comparison with screw fastening, but requires expensive equipment.
Furthermore, it
is alternatively conceivable to hold the two paarts 34 and 35 together in a
simple
manner with a clamping device, which can be released quickly if necessary,
after
they reach the end position against one another.
To expedite the formation of the undercut surfaces, and for improvement in the
uniform filling out of the radii of the recess 32, and thus to achieve optimum
mating
between walls 4 and 5, the mandrel 31 has an axial fluid passage 37 from which
a
radial passage 38 branches off, which leads into the recess 32 at its bottom
39.
Passages 37 and 38 can be only in one of the parts 34 or 35, or - as shown in
Fig. 5
- pass through part 34 at passage 37 and terminate in part 35, and be formed
as
regards passage 38 by an opening at both ends 35 of parts 34 and 35. By
feeding a
high-pressure fluid through passages 37 and 38 the walls 4 and 5 are made to
flow,
so that, being driven by the fluid pressure column 25 into the corner areas of
the
recess 32, they can conform to the walls of the corner areas of recess 32. The
variant described can be used, on account of its localized fluid pressure,
also
wherever some other deformation of the hollow profile 3 is not desired.
Another advantageous variant is shown in the embodiment seen in Figure 6.
Unlike
the variant in Figure 5, the recess wall 33 of parts 34 and 35 have undercut
surfaces
41 as seen in longitudinal section. Instead of the fluid pressure column 25, a
hollow
or solid plunger can be used, as also in the case of the variant in Figure 5.
In order
to press the wall material of walls 4, 5 into the recess 32 such that it will
come into
conforming contact with the undercut surfaces 41, first an indentation of
shallow
depth is produced by the fluid pressure column 25 or by the plunger 8 in the
two walls
4 and 5. The two parts 34 and 35 have their faces 36 still spaced apart from
one
another at this time. After the indentation is produced, the two parts 34 and
35 are
driven together in the directions of the arrows, while the wedge-shaped
closing edges
42 of parts 34 and 35 drive the material of walls 4 and 5 and pinch them. In
this
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Attorney Docket: 095309.55734US
pinching action the wall material applies itself simply to the undercut
surfaces 41 until
the two faces 36 come in contact with one another. To allow this to be
accomplished
surely, so that no wall material gets on the faces 36, care must be taken to
see that
either the indentation is small enough when parts 34 and 35 begin to move
toward
one another, or the bottom 39 of the recess 32 must be at least so deep that
the wall
material of the indentation 10 will not come in contact with the bottom 39
until the
faces 36 of parts 34 and 35 are in contact with one another. The described
variant
method has the advantage that, for the formation of the indentation 10, wall
material
is fed axially by the parts 34 and 35, so that harmful effects are prevented.
Furthermore, due to the active axial action of parts 34 and 35 on the wall
material,
the variant is a method as to how a virtually complete mating together of two
walls 4
and 5 with undercut surfaces 41 can be achieved.
In an additional advantageous embodiment according to Figure 7, the component
2
can be in the form of a hollow profile which is assembled together before it
is
fastened to the hollow profile 3. A tubular elastic bellows 40 can be
introduced, as
shown in this embodiment in Figure 7, into the hollow profile 3 which here is
internal,
and it supports the hollow profile 3 while the plunger 8 thrusts internally,
while within
the bellows 40 a fluidic high internal pressure is applied, which on the one
hand
expands the hollow profile 3 during the procedure of pressing with the plunger
8,
while within the bellows 40 a fluidic high pressure is applied, which expands
the
hollow profile 3 together with the tubular component 2, and in cooperation
with the
plunger 8, as already described in the embodiment in Figures 3 and 4, forms
the
undercut surfaces of the indentation 10. The bellows 40 thus forms part of a
matrix
which additionally consists of the pressure medium itself, into which the
walls 4 and 5
can be pressed. With the bellows 40 it is brought about that the hollow
profile 3 is
not wetted by the pressure medium, which is desirable for easily corroded
materials.
Furthermore, the bellows 40 prevents hydraulic fluid from leaking out
uncontrolled in
the event of any kind of crazing or cracking in the indentation 10, and provid
for any
unwanted loss of pressure which would undermine any reliable shaping of
undercut
surfaces. Instead of the bellows 40 the device 1 can contain a diaphragm
fastened,
for example, to the axial plunger.
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Attorney Docket: 095309.55734US
For additional strengthening of the bond between the walls 4 and 5, they can
be
brushed or coated with an adhesive before they are brought together, the
tackiness
of the adhesive being activated, preferably by heat treatment after the double-
wailed
indentation is formed. As an alternative the walls 4 and 5 can also be coated
with a
solder, and after the indentation 10 is formed they can be soldered together
by heat
treating the solder and the component 2 and hollow profile 3 in an oven.
The hollow profile 3 itself can be made from pipe skelp rolled and then welded
along
the seam. In like manner, extruded or rolled shapes can be considered.
However,
two superimposed skelps can be shaped by means of internal high fluidic
pressure,
and the impression can be performed in an economic manner during or after
formation by internal high fluidic pressure. The hollow profile 3 can have a
circular
cross section tike the tubular raw material or it can have other cross-
sectional shapes
which can be obtained by flattening, bending and pressing or the like.
Otherwise, the indentation 10 can also run like an annular groove around the
component 2 and the hollow profile 3. The compression means can be the
pressure
column 25 as well as a segmented annular die surrounding .component 2 as well
as
hollow profile 3.
Moreover, an additional advantage of the embodiments in Figures 4 and 7 should
be
mentioned at this point. As a result of the high internal pressure, when the
walls 4
and 5 are forced in by the plunger $ or the pressure column 25, due to the
resistance
offered by the high internal pressure, no sinking deformations with great
bending radii
are formed in the marginal area adjacent the indentation 10 to the detriment
of the
dimensional stability of the external shape of the hollow profile 3. Thus, the
shape of
the contour remains unaffected by the forcing inward, which among other things
satisfy requirements as to the external appearance of the assembly of the
hollow
profile 3 to the component 2.
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