U.S. patent application number 10/373240 was filed with the patent office on 2003-08-28 for lightweight constructional element with external ribbing.
Invention is credited to Goldbach, Hubert, Kappenstein, Reinhold.
Application Number | 20030159261 10/373240 |
Document ID | / |
Family ID | 27675147 |
Filed Date | 2003-08-28 |
United States Patent
Application |
20030159261 |
Kind Code |
A1 |
Kappenstein, Reinhold ; et
al. |
August 28, 2003 |
Lightweight constructional element with external ribbing
Abstract
A lightweight constructional element (100) is disclosed. The
lightweight constructional element (100) comprises: (a) a
shell-shaped basic body or shell (1), e.g., fabricated from metal,
having interior (20) and exterior (23) surfaces, the interior
surfaces (23) of the basic body define an interior space (26); and
(b) reinforcing ribs (2a, 2b) of plastics material, preferably
thermoplastic material, which are fixedly attached to the exterior
surface (23) of basic body (1). The reinforcing ribs are fixedly
attached to the exterior surface of said basic body by means of
discrete attachment points {which may include, for example,
apertures (3a), slots (3f), beads (3b) and/or protrusions (3c)}.
Articles of manufacture that may include the lightweight
constructional element include, for example, structural components
of motor vehicles (e.g., a cross car beam) and aircraft, and a
structural component having a channel for receiving at least one of
a cable and a gas.
Inventors: |
Kappenstein, Reinhold;
(Odenthal, DE) ; Goldbach, Hubert; (Ratingen,
DE) |
Correspondence
Address: |
BAYER POLYMERS LLC
100 BAYER ROAD
PITTSBURGH
PA
15205
US
|
Family ID: |
27675147 |
Appl. No.: |
10/373240 |
Filed: |
February 24, 2003 |
Current U.S.
Class: |
29/17.1 |
Current CPC
Class: |
B29C 45/14311 20130101;
B29L 2031/3002 20130101; Y10T 29/30 20150115; B62D 29/001 20130101;
B62D 29/004 20130101; B62D 21/17 20130101 |
Class at
Publication: |
29/17.1 |
International
Class: |
E04C 002/26 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2002 |
DE |
10208953.1 |
Claims
What is claimed is:
1. A lightweight constructional element comprising: (a) a
shell-shaped basic body having interior and exterior surfaces, the
interior surfaces of said basic body defining an interior space;
and (b) reinforcing ribs of plastics material which are fixedly
attached to the exterior surface of said basic body, wherein said
reinforcing ribs are fixedly attached to the exterior surface of
said basic body by means of discrete attachment points, said
reinforcing ribs being one of directly and indirectly fixedly
attached to the exterior surface of said basic body.
2. The lightweight constructional element of claim 1 wherein said
basic body is fabricated from a material selected from at least one
of thermoset plastics material, thermoplastic materials and
metal.
3. The lightweight constructional element of claim 1 wherein the
plastics material of said reinforcing ribs is selected from at
least one of thermoset plastics material and thermoplastic
materials.
4. The lightweight constructional element of claim 1 wherein said
discrete attachment points comprise at least one of: a plurality of
perforations; a plurality of beads; and a plurality of
protrusions.
5. The lightweight constructional element of claim 1 wherein said
basic body has a plurality of perforations each having a plane,
said reinforcing ribs are fixedly attached to the exterior surface
of said basic body by means of the plastics material of said
reinforcing ribs extending through at least some of said
perforations, extending beyond the plane of said perforations and
into the interior space of said basic body, said perforations being
selected from at least one of apertures and slots.
6. The lightweight constructional element of claim 1 wherein said
basic body has a shape selected from-substantially U-shapes and
substantially V-shapes each having two sidewalls, each sidewall
having a rim, said reinforcing ribs are further fixedly attached to
the exterior surface of said basic body by means of plastic
material of said ribs at least partially encasing said rims.
7. The lightweight constructional element of claim 6 wherein the
rim of each sidewall has a substantially laterally outwardly
extending flange, and said reinforcing ribs are further fixedly
attached to the exterior surface of said basic body by means of
plastic material of said ribs at least partially encasing said
flanges.
8. The lightweight constructional element of claim 4 wherein said
reinforcing ribs are fixedly attached to the outer surface of said
basic body by means of a process of molding plastics material onto
the exterior surface of said basic body, the molded-on plastics
material at least one of: (i) extending through at least some of
said perforations and into the interior space of said basic body;
(ii) filling at least some of said slots; (iii) filling at least
some of said beads; and (iv) encasing at least partially at least
some of said protrusions.
9. The lightweight constructional element of claim 1 wherein the
exterior surfaces of said basic body are at least partially encased
in plastics material.
10. The lightweight constructional element of claim 1 wherein at
least a portion of the interior surfaces of said basic body are
encased with plastics material.
11. The lightweight constructional element of claim 1 wherein said
basic body has a shape selected from substantially U-shapes and
substantially V-shapes.
12. The lightweight constructional element of claim 1 wherein said
basic body has a shape selected from substantially U-shapes and
substantially V-shapes each having two sidewalls, each sidewall
having a substantially laterally outwardly extending flange, said
lightweight constructional element further comprising a cover
plate, said cover plate being fixedly attached to each of said
flanges and covering at least a portion of the interior space of
said basic body.
13. The lightweight constructional element of claim 12 wherein said
cover plate is fixedly attached to said basic body by means of
plastics material encasing each of said flanges and at least a
portion of said cover plate that abuts each of said flanges.
14. The lightweight constructional element of claim 12 wherein each
of said cover plate and said flanges have plurality of
perforations, each perforation having a plane, at least some of the
perforations of said cover plate and said flanges are aligned with
each other, the aligned perforations forming a plurality of aligned
perforations each having a plane, said cover plate being fixedly
attached to said basic body by means of plastics material extending
through and beyond the plain of least some of the aligned
perforations, said perforations being selected from at least one of
apertures and slots.
15. The lightweight constructional element of claim 12 wherein said
cover plate forms an airtight seal over said interior space of said
basic body by means of at least one of a welded joint, a bonded
joint and a sealing agent positioned between each of said flanges
and at least a portion of said cover plate that is fixedly attached
to each of said flanges.
16. The lightweight constructional element of claim 1 further
comprising at least one dividing wall positioned within the
interior space of said basic body.
17. The lightweight constructional element of claim 12 wherein said
basic body and said cover plate are each independently fabricated
from at least one material selected from the group consisting of
sheet metal, diecast metal and fiber-reinforced plastics
material.
18. The lightweight constructional element of claim 1 wherein the
plastics material of said reinforcing ribs is a thermoplastic
material selected from at least one of polycarbonate, polyester,
polyurethane, polystyrene, polyamide and polyalkylene.
19. An article of manufacture comprising the lightweight
constructional element of claim 1 wherein said article is selected
from: a structural component of a motor vehicle; a structural
component of an aircraft; and a structural component having a
channel for receiving at least one of a cable and a gas.
20. An article of manufacture comprising the lightweight
constructional element of claim 1 wherein said article is selected
from: an instrument panel support; and a cross-car beam.
21. The lightweight constructional element of claim 1 wherein said
reinforcing ribs form a continuous unitary structure on the
exterior surface of said basic body.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATION
[0001] The present patent application claims the right of priority
under 35 U.S.C. .sctn.119 (a)-(d) of German Patent Application No.
102 08 953.1, filed Feb. 28, 2002.
FIELD OF THE INVENTION
[0002] The invention relates to a lightweight constructional
element comprising a shell-shaped basic body, in particular of
metal, having reinforcing ribs of plastics material, in particular
of thermoplastic plastics material, which are permanently fixed to
the basic body.
BACKGROUND OF THE INVENTION
[0003] Stiff, high-strength lightweight structural elements with
internal ribbing already exist in what is commonly referred to as
"hybrid technology" (generally, a technology involving the
combination of metal inserts with thermoplastic plastics material).
For reasons of space constraints, however, such structures do not
meet the requirements associated with integration of additional
components and application (e.g., conduits for wiring and air
transport, and other channels, within the interior of the basic
body).
[0004] Previously, instrument panel supports or so-called cross-car
beams or cross-members in motor vehicles have been produced from
steel tubing with various welded-on or screwed-on parts. These
parts have relatively high weight. Moreover, with these elements
the above-mentioned direct molding-on of further constructional
elements to the basic body using the injection-molding process is
impossible or possible only with difficulty.
[0005] EP 370 342 A1discloses a lightweight constructional element
consisting of a shell-shaped profile section with internal
supporting ribs consisting of molded-on thermoplastic plastics
material. Although this constructional element may be used as a
support structure, in particular in the form of plastics-metal
composite bodies, its further technical application as a
constructional element is typically limited.
[0006] It is an object of the invention to develop a lightweight
constructional element which is relatively simple to manufacture
and has good physical properties, such as high stiffness and
strength. Such a newly developed lightweight constructional element
preferably consists of one or optionally a plurality of
(shell-shaped) basic bodies. It is desirable that the basic bodies
of such newly developed lightweight construction elements must
provide channels for wiring or air transport, and further
applications. It is further desirable that such newly developed
lightweight construction elements have a level of stiffness that is
at least comparable to that of prior art structures, such as metal
tube cross-car beams.
SUMMARY OF THE INVENTION
[0007] In accordance with the present invention, there is provided
a lightweight constructional element (100) comprising:
[0008] (a) a shell-shaped basic body or shell (1), e.g., fabricated
from metal, having interior (20) and exterior (23) surfaces, the
interior surfaces (23) of said basic body defining an interior
space (26); and
[0009] (b) reinforcing ribs (2a, 2b) of plastics material,
preferably thermoplastic material, which are fixedly (or
permanently) attached to the exterior surface (23) of said basic
body (1),
[0010] wherein said reinforcing ribs are fixedly attached to the
exterior surface of said basic body by means of discrete attachment
points {which may include, for example, apertures (3a), slots (3f),
beads (3b) and/or protrusions (3c)}, said reinforcing ribs being
one of directly and indirectly fixedly attached to the exterior
surface of said basic body.
[0011] The features that characterize the present invention are
pointed out with particularity in the claims, which are annexed to
and form a part of this disclosure. These and other features of the
invention, its operating advantages and the specific objects
obtained by its use will be more fully understood from the
following detailed description and accompanying drawings in which
preferred embodiments of the invention are illustrated and
described.
[0012] Unless otherwise indicated, all numbers or expressions, such
as those expressing structural dimensions, quantities of
ingredients, etc. used in the specification and claims are
understood as modified in all instances by the term "about."
[0013] As used herein and in the claims, the term "perforation"
means a hole of any size or configuration, typically present in the
basic body (1) and optionally the flanges (8) of the basic body,
and includes, but is not limited to, apertures and/or slots.
[0014] As used herein and in the claims, the term "aperture" means
a perforation having substantially similar cross dimensions, and
includes, but is not limited to shapes selected from substantially
circular, substantially square, and/or substantially
triangular.
[0015] As used herein and in the claims, the term "slot" means a
perforation that is generally elongated in one dimension relative
to the other dimension(s) of the perforation, and includes, but is
not limited to, rectangular slots and elliptical slots.
[0016] As used herein and in the claims, and unless otherwise
noted, the term "plastics material" means thermoplastic materials
(plastics materials that are substantially free of a 3-dimenstional
crosslink network) and/or thermoset plastics materials (plastics
materials having 3-dimensional crosslink network).
[0017] As used herein and in the claims, the term "directly fixedly
attached" with regard to the exterior reinforcing plastic ribs
means that the reinforcing ribs are form- and force-closed
connected to the basic body by means of apertures or slots.
[0018] As used herein and in the claims, the term "indirectly
fixedly attached" with regard to the exterior reinforcing plastic
ribs, means that the reinforcing ribs are force-closed connected to
the basic body by means of beads or protrusions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a representative perspective side view of a
substantially closed lightweight constructional element (103)
according to the present invention, which includes a cover plate
(5a);
[0020] FIG. 2 is a representative perspective side view of an open
lightweight constructional element (100) according to the present
invention, which includes substantially laterally outwardly
extending (or doubly angled) reinforcing flanges (8);
[0021] FIG. 3 is a representative section through a closed profile
section of substantially closed lightweight constructional element
(105) that is similar to that of FIG. 2; and
[0022] FIG. 4 is a representative section through a lightweight
constructional element (107) similar to that of FIG. 3 having
apertures in the basic body and in the cover plate.
[0023] In FIGS. 1 through 4, like reference numerals designate the
same components.
DETAILED DESCRIPTION OF THE INVENTION
[0024] In an embodiment of the present invention, the basic body is
fabricated from a material selected from at least one of thermoset
plastics material, thermoplastic materials and metal. In a further
embodiment, the plastics material of the reinforcing ribs is
selected from at least one of thermoset plastics material and
thermoplastic materials.
[0025] The connection between the reinforcing ribs and the basic
body is preferably effected at or by means of perforations (e.g.,
apertures and/or slots) through which the plastics material passes
and extends beyond the plane of the perforations (e.g., apertures
and/or slots).
[0026] Increased or improved stiffness of the constructional
element may be obtained in a preferred embodiment of the present
invention when the connection between the reinforcing ribs and the
basic body is additionally effected by means of at least partially
encasing the rim portions of the basic body by means of plastics
material. More particularly, in an embodiment of the present
invention the basic body of the lightweight constructional element
has a shape selected from substantially U-shapes and substantially
V-shapes each having two sidewalls (e.g., substantially opposed
sidewalls), each sidewall having a rim, and the reinforcing ribs
are further fixedly attached to the exterior surface of the basic
body by means of plastic material of the ribs at least partially
encasing the rims.
[0027] In a preferred embodiment of the present invention, the
lightweight constructional element is given still greater stiffness
if the basic body has in its rim portion an angled reinforcing
flange, in particular a doubly-angled reinforcing flange. More
particularly, the basic body of the lightweight constructional
element has a shape selected from substantially U-shapes and
substantially V-shapes each having two sidewalls (e.g.,
substantially opposed sidewalls), each sidewall having a
substantially laterally outwardly extending flange (e.g., an angled
reinforcing flange), and said reinforcing ribs are further fixedly
attached to the exterior surface of the basic body by means of the
plastic material of the ribs at least partially encasing the
flanges.
[0028] These angled rim portions (or laterally outwardly extending
flanges) of the basic body can be variously formed (e.g., in
accordance with the deep-draw process of the metal part), and their
configurations are, for example, primarily determined by the design
requirements of the constructional element as a whole.
[0029] The lightweight constructional element is particularly
simple to manufacture but also simple to detach (e.g., separate the
reinforcing ribs from the basic body or shell) for the purposes of
plastics material recycling, if the connection between the
reinforcing ribs and the basic body is effected by means of the
plastics material molded onto the exterior surfaces of the basic
body, e.g., by means of the injection-molding technique, as will be
discussed in further detail herein.
[0030] In a particularly preferred embodiment, to further increase
the strength of the lightweight constructional element, the
exterior surface of the basic body ( in addition to the reinforcing
ribs) is encased with plastics material. The exterior encasing
plastics material may optionally be continuous with the plastics
material of the exterior reinforcing ribs.
[0031] Particularly advantageous with respect to corrosion
protection, e.g. of metal inserts, is a preferred lightweight
constructional element of the present invention, in which the
interior surfaces of the basic body are at least partially encased
in plastics material. The interior encasing plastics material may
optionally be continuous with the plastics material of the exterior
reinforcing ribs that extends through perforations in the basic
body into the interior space of the basic body, and thereby serving
to further fixedly attach the exterior reinforcing ribs to the
exterior surface of the basic body.
[0032] The spatial form of the shell of the lightweight
constructional element can be freely selected, depending on the
application. A preferred constructional form of the lightweight
constructional element is characterized in that the the basic body
has a shape is selected from substantially U-shapes and/or
substantially V-shapes (relative to the profile section of the
basic body).
[0033] The advantage of the basic body of the present invention, as
compared to closed box-section basic bodies, lies in the greater
simplicity of its manufacture, e.g., by means of the extrusion
process.
[0034] To form wiring or air conduits the shell-shaped basic body
may optionally be closed with a cover plate. A lightweight
constructional element is therefore preferred which is
characterized in that at least one additional cover plate enclosing
the interior space of the basic body at least partially, and in
particular completely, is attached across (or over) the interior
space of the basic body. In an embodiment of the present invention,
the basic body has a shape selected from substantially U-shapes and
substantially V-shapes each having two sidewalls, each sidewall
having a substantially laterally outwardly extending flange, the
lightweight constructional element further includes a cover plate,
which is fixedly attached to each of the flanges and covers at
least a portion of the interior space of the basic body.
[0035] The cover plate can project in any desired manner beyond the
side portions (or sidewalls) of the lightweight constructional
element. In which case it may then optionally contain further
functional elements such as dashboard parts, etc., and can
therefore serve as a further design feature.
[0036] In a particularly preferred form of the lightweight
constructional element of the present invention, the cover plate is
jointly encased by plastics material in the rim portion of the
basic body to close the interior space. In an embodiment, the cover
plate is fixedly attached to the basic body by means of plastics
material encasing each of the flanges and at least a portion of the
cover plate that abuts (or is at least superposed over) each of
said flanges.
[0037] The stiffness of the constructional element can be further
increased if the cover plate is preferably combined with the basic
body by means of apertures or slots arranged one above the other,
through which the plastics material passes and extends beyond the
plane of the apertures or slots. A kind of riveted plastics
connection is thereby produced. In an embodiment of the present
invention, each of the cover plate and the flanges have a plurality
of perforations, each perforation having a plane, at least some of
the perforations of the cover plate and flanges are aligned with
each other, the aligned perforations form a plurality of aligned
perforations each having a plane, the cover plate is fixedly
attached to the basic body by means of plastics material extending
through and beyond the plain of least some of the aligned
perforations. The perforations of the aligned perforations may be
selected from apertures and/or slots.
[0038] If an airtight channel is required, the connection between
the closure plate and the shell-shaped basic body or the
lightweight constructional element may be effected by means of a
welded or bonded joint, and/or an additional sealing element such
as a rubber seal may be inserted.
[0039] For certain applications (e.g., air conduit, etc.) a
preferred lightweight constructional element is advantageous which
is characterised in that the attachment point of the cover plate to
the basic body is closed in an airtight manner by means of a welded
or bonded joint or by means of a sealing agent, in particular a
rubber seal. The cover plate, in an embodiment of the present
invention, forms an airtight seal over the interior space of the
basic body by means of a welded joint, a bonded joint and/or a
sealing agent positioned between each of the flanges and at least a
portion of the cover plate that is fixedly attached to each of the
flanges.
[0040] A preferred form of the lightweight constructional element
in which the interior of the basic body has at least one dividing
wall, in particular of thermoplastic plastics material, has proved
successful in separately accommodating a plurality of conduits.
[0041] Sheet metal, preferably steel or aluminum sheet, diecast
metal, in particular aluminum, zinc or magnesium, or
fiber-reinforced plastics material or composite material may be
used as the preferred material for the basic body and optionally
the cover plate of the lightweight constructional element.
[0042] As a preferred material for the reinforcing ribs and
optionally the encasement of the lightweight constructional
element, a plastics material selected from the series:
polycarbonate, polyester, in particular PET or PBT, polyurethane,
polystyrene, polyamide, polyalkylene, in particular polypropylene,
is used.
[0043] Lightweight, structural and housing elements with high
functionality find application in the vehicle industry, in
mechanical engineering and the appliances industry, in the
electrical industry and in other constructional elements.
[0044] In particular, these elements can be used in the vehicle
industry as instrument panel supports or so-called cross-car beams
(CCBs).
[0045] If applicable, further constructional elements such as trim
or functional parts for the dashboard area can be directly molded
on to the exterior areas of the basic body or the ribbing, using
the injection-molding process.
[0046] Manufacture of the above-mentioned lightweight structural
elements is possible in a reasonable manner with a relatively short
production time, especially using the injection-molding process. In
a preferred embodiment of the present invention discrete attachment
points include a plurality of perforations, a plurality of beads
and/or a plurality of protrusions. The reinforcing ribs are
preferably fixedly attached to the outer surface of the basic body
by means of a process of molding plastics material onto the
exterior surface of the basic body, the molded-on plastics material
at least one of: (i) extends through at least some of the
perforations and into the interior space of the basic body; (ii)
fills at least some of the slots; (iii) fills at least some of the
beads; and (iv) encases at least partially at least some of the
protrusions. The process of molding plastics material onto the
exterior surface of the basic body includes: (i) injection-molding
(in the case of thermoplastic, materials): (ii)
reaction-injection-molding (in the case of thermoset plastics
materials, such as 2-pack thermoset or thermosetable polyurethane
compositions); and (iii) a combination of injection-molding and
reaction-injection-molding (in the case of plastics compositions
that include both thermoplastic materials and thermoset plastic
materials or components).
[0047] The invention therefore further relates to the application
of a lightweight constructional element according to the invention
as a structural component or support structure for motor vehicle or
aircraft construction, in particular as a support structure with a
channel for wiring or gas, particularly preferably with an air
channel, and particularly preferably as an instrument panel support
or cross-car beam. Articles of manufacture that may include the
lightweight constructional element of the present invention
include, but are not limited to: a structural component of a motor
vehicle; a structural component of an aircraft; and a structural
component having a channel for receiving at least one of a cable
and a gas. Further articles of manufacture that may include the
lightweight constructional element of the present invention
include, but are not limited to: an instrument panel support; and a
cross-car beam.
[0048] In a particularly preferred embodiment of the present
invention, the reinforcing ribs, of the lightweight constructional
element, form a continuous unitary structure on the exterior
surface of the basic body.
[0049] The invention is described in further detail below, in an
exemplary manner, with reference to the drawing figures.
EXAMPLES
Example 1
[0050] A U-shaped profile section (basic body or shell) 1 of sheet
steel (thickness 0.8 mm) with angled flanges 8 (in the rim region
29) is provided on its exterior with cruciform ribs 2a of
thermoplastic plastics material (e.g., of glass-fiber reinforced PA
6). The ribbing is molded on to the profile section using the
injection-molding process, as described previously herein. Disposed
across the interior of the profile section 1 is a cover 5a which is
permanently fixed to the rim 8 of the profile section 1 by means of
a molded rim encasement 4.
[0051] At certain points of its surface the profile section 1 has
perforations in the form of apertures 3 through which the
thermoplastic material passes. The plastics material here forms a
riveted connection 3a similar to that depicted in FIG. 3. The
profile section 1 according to FIG. 1 forms part of a heated air
conduit.
Example 2
[0052] FIG. 2 represents a profile section 1, similar to that of
Example 1, in which the profile section 1 has doubly-angled
reinforcing flanges 8. Here the lateral reinforcing ribs 2b are
disposed perpendicularly with respect to the extension and flanges
of the profile section.
[0053] The ribs 2b are attached at profile section slots 3f by
means of thermoplastic material passing through the profile section
1. Here the profile section is formed as an open box section.
Example 3
[0054] In the metal profile section 1 shown in FIG. 3 the internal
surfaces 20 are encased by thermoplastic plastics material 9, which
can be seen in cross-section. Similarly to that depicted in FIG. 1,
the profile section 1 has a cover plate 5a which is attached to the
profile section 1 by means of bonding agent 6.
[0055] In place of the bonding agent 6, attachment by a welded edge
joint can also be provided (not shown). In case of a welded joint
the same material/plastics material may be used for the cover plate
as for the adjoining interior encasement.
[0056] The cover plate 5a is manufactured, in this case, from
glass-fiber reinforced thermoset material.
[0057] Three variants of attachment points are shown in
cross-section in FIG. 3: a simple aperture 3a, a trapezoidal bead
3b, and a hemispherical protrusion 3c.
[0058] The profile section 1 has doubly-angled flanges 8 which are
encased in thermoplastic plastics material 4 and, in combination
with the attachment points 3a, 3b, 3c, ensure the strength of the
composite.
[0059] For further stiffening of the constructional element the
cover plates 5a may have reinforcing beads 7 disposed in a
longitudinal, transverse or cruciform manner.
Example 4
[0060] In FIG. 4 a metal profile 1 is shown in cross-section, which
has external plastic ribbing 2a, 2b, similarly to the profile
section according to Example 2. Here again, through the
injection-molding process, the thermoplastic material passes
through the profile section basic body 1 at the apertures 3a, 3e or
the slots 3f and forms attachment points.
[0061] Attached across the interior of the profile section 1 is a
metal cover 5b which is seated directly on the metal profile 1 and
forms therewith an electrically shielded channel 26. Apertures 3g
in the cover 5b are disposed directly above the apertures 3e or
slots 3f in the profile section 1 and are riveted by means of the
plastics material to the profile section 1.
[0062] In view of the angled flange portion of the basic body in
FIG. 3, only longitudinal ribs 2b of plastics material on the side
areas of the basic body, according to the direction of deformation,
are consequently now possible as reinforcement.
[0063] The profile section also has over its entire exterior
surface 23 an outer encasement 10 of the same thermoplastic
material as the ribs 2a, 2b. In this case the attachment points 3d,
3e, 3f do not need to be located directly in the area of the ribs
2a, 2b.
[0064] The process of attaching a metal cover plate 5b may be
executed directly by the normal injection-molding process of the
lightweight constructional element or using the so-called
"in-mold-assembly-process", instead of a conventional joining
process (bonding, welding 6).
[0065] Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood
that such detail is solely for that purpose and that variations can
be made therein by those skilled in the art without departing from
the spirit and scope of the invention except as it may be limited
by the claims.
* * * * *