Note: Descriptions are shown in the official language in which they were submitted.
CA 02345298 2001-03-23
Method and device for producing a van body, and van body thus produced
The invention relates to a method for producing a box-type van body for
transporting
vehicles.
Such bodies are already known in a large number of designs. Thus, van bodies
are
known which are assembled from individual plate shaped elements and are joined
at
edge areas, if needed also in the planar areas by means of profiled bars. The
assembling
of such a van body is, however, quite time consuming and, therefore, also
expensive.
Furthermore, with the conventionally used wooden boards a comparable large
weight is
arrived at.
Further known are aluminum van bodies of the so called cIarnped van body
assembly
design, in which aluminum sheets are joined by profiled bars. Also here the
drawback
exists that a comparatively high weight is arrived at and that the assembling
is quite
time consuming. A further drawback is that the comparativel'.y thin metal
sheets,
specifically if used for motor vehicles, are easily exited to vibrate in case
of uneven
roadways and then produce a corresponding noise.
In order to seal between the plates and the profiles plastic m<~terial strips
are made use
of which, however, grow porous after a prolonged time due to the influence of
the
relative movements between plates and profiled bars and also under the
influence of
W-rays and then lead to leaky areas at the van body.
In the case of the clamped van body assembly design wooden panels are quite
often
placed at the inner side of the thin outer skin of aluminum. Means for
securing the cargo
for instance in form of belts or similar can than be mounted to these wooden
panels.
Furthermore, the inner wood paneling shall provide for a protection against
damages by
the cargo. Further van bodies are known which consist of compound plates with
a
foamed PU- core and GFK-layers laminated thereupon. Such bodies are, however,
extremely expensive and quite demanding regarding their production.
CA 02345298 2001-03-23
-2-
AlI three of these various embodiments of van-bodies in accordance with the
prior art
have in common that due to the multitude of materials, only a limited or
inferiorly
workable possibility of repair is given. In case of the clamped van body
design, for
instance, there is a problem that the outer skin which consists of a thin
aluminum
material can easily be damaged for instance by branches, but than, however,
considerable additional operations are necessary, namely they removing of the
inner
wood paneling in order to access the area to be repaired. In case of a
repairing of the
aluminum-insert profile bars a welding without a considerable assembly work is
impossible because otherwise the bordering materials would not stand up
against the
heat strain.
Object of the present invention is to provide a method for producing a van
body which
can be practiced specifically easy and fast and necessitates a small
expenditure of
machines only. A accordingly produced van body shall display a excellent
sealing
property and be resistant against influences of the environment, shall have a
small
weight and if needed shall lend itself to a easy recycling. Finally, a device
for producing
the van body shall be provided which is of a simple design and is inexpensive
and
which also can be operated if necessary by non-professionals.
With regard to the method of production for a van body in accordance with the
invention it is proposed to heat a mufti-layer flat part consislting
substantially of
thermoplastic material having a supporting center and covering layers at both
sides
thereof, of which the surface corresponds to at least two adjoining side walls
of the van
body at substantially linear zones which correspond to edge boundaries of the
adjoining
side walls of the van body and to bend it at those zones.
The main assembly operation for producing the van body consists in a folding
or
bending, respectively of a correspondingly dimensioned sandwich flat part
under
influence of heat, so that thereafter at least the largest part of the van
body is available
consisting practically of one part.
CA 02345298 2001-03-23
-3-
Experiments have shown that that the expenditure on time fix a producing of
such a van
body amounts to only a fraction of up to one tenth of the time needed to
produce a
conventional design.
The use of a thermoplastic material for the flat part to be foamed allows a
simple
working under the influence of heat and has due to the practically homogeneous
structure of the material the advantage of a considerable saving of material
and the
substantial advantage that it can be easily recycled. Additionally, a large
advantage is
the considerable saving on weight which leads to a great many advantages
resulting
thereof, specifically in combination with vehicles.
Advantageously several mufti-layer sandwich plates adjoining each other at
their narrow
faces and consisting substantially of a thermoplastic material, having a
supporting core
and at both sides thereof covering layers are joined in a thermoplastic manner
to form
the flat part, whereby to this end a portion of the supporting core of the
face side of one
of the plates to be joined is removed for producing a receiving recess and
from the other
sandwich plate a portion of the cover layers is removed at its face side, then
the core
zone is inserted into the receiving recess and thereafter the fiwo sandwich
plates are
joined under influence of pressure and heat.
This also adds substantially to a simple production, because the sandwich
plates can be
produced practically in series and unitarily relative to the size; independent
from the size
of the flat part. The sandwich plates used can be produced practically
endlessly at a
predetermined width and can then be cut to size in accordance with the
circumferential
length of a van body. Should the width of the sandwich strand not be
sufficient, a
corresponding number of further sandwich strands may be added thereto
laterally in
accordance with the above described procedure.
The connecting together of the individual sandwich plates is possible at a
small
expenditure due to the property of being able to be welded in a thermoplastic
manner,
and due to the zone wise overlapping meshing a rigid connection is arrived at
and due to
this a practically homogeneous structure having at all areas substantially the
same
strength properties. Advantageously it is foreseen that alI sides located at
least in a
CA 02345298 2001-03-23
-4-
direction of the circumference of the van body structure are; part of the flat
part and that
after the folding of the sides the possibly each other adjoining free ends are
joined
together at least under the influence of heat, preferably meshing with each
other.
Thus, it is possible to produce in practically one production step a complete
van body
which needs only a few additional processing steps, for instance in order to
connect it to
the chassis of a vehicle or for the mounting of a door or sirrular. There
exists, thereby,
the possibility to produce in a interconnected manner the side walls, the roof
and the
floor from one single piece or even additionally to include at least one of
the front walls,
It is, furthermore, foreseen, that for a joining of a seen in ci:rcumferential
direction angle
shaped or U-shaped or closed partial van body structure to a wall extending at
an angle
thereto and consisting of one or several sandwich plates, at the one hand a
supporting
core portion is removed partly at one of the facing ends of one wall and at
the face end
of the other wall the covering layers are removed up to a certain zone, and
that the cover
layers of the zone without the supporting core are joined in a thermoplastic
manner and
in an overlapping manner at least to the zone of the other wall having no
covering
layers.
By means of this stable joints can also be produced at the corner areas of
walls joined to
each other. Also here a welding of the thermoplastic material is carried out
by an
influence of heat and no additional joining elements are needed.
A advantageous embodiment of the invention foresees that a preferably
thermoplastic
tube is inserted in the flat part at least at the zone of a foreseen fold and
that the tube is
heated for a folding of the flat part and the folding is carnedf out
thereafter.
The inserted tubes can be used as installation channels, specifically for
electric cables.
It is, however, especially advantageous if the supply of heat proceeds by
tubes located
in fold zones at the zones of the tubes and especially through the tubes. By
this supply
of heat through the tube the plastification of the folding zone proceeds from
the inside
and accordingly especially effective and fast. In this case the. zones of the
folds are
determined by the location of the tubes and this forms a additional
stabilization of the
edge.
CA 02345298 2001-03-23
- S -
In order to mount a door or similar there exists the possibility that at least
at one
circumferentially extending face rim of a in circumferential direction U-
shaped or
closed part-van body structure a portion of the core area is removed for the
forming of a
receiving groove and a end profile piece is set into this receiving groove and
joned
therein. Hinge and/or Iock parts may be mounted to this end profile piece.
This end
profile piece may if needed be formed of a profiled aluminum strip, for
instance a
square tube. Instead of a aluminum tube it may also be possible to insert a
profiled strip
of a thermoplastic material which may be welded in a thermoplastic manner to
the
sandwich plate.
In order to form a hinge and for a mounting of a door it is I>ossible to
locate between
walls of the van body which are to be pivotally mounted tol;ether recesses at
their
longitudinal edges which face each other in a in the longitudinal direction
staggered
manner, into which the respective remaining edge portions of the other side
engage, and
that pivot pins are inserted into the not removed edge areas. Also in this
case a closing
off profiled strip may be inserted into the outer edges,
According to a further embodiment of the invention it is foreseen to slit a
thermoplastic
tube in its longitudinal direction and to place heating wires <~t the edges of
the slit, and
to insert thereafter the tube with the slit facing the inner side of the fold
at the angled
area between adjoining walls into the flat piece or between l:he sandwich
plate(s),
respectively, and that thereafter during the thermoplastic folding the edges
of the slits
are placed against each other and welded together.
In the folded or bent, respectively state of the flat part a addfitional
reinforcement can be
obtained by the melting together of the edges of the slits which in the
initial position are
at a distance from each other corresponding to the foreseen fold. During the
folding
process proper the force needed for the folding is reduced.
The invention refers also to a van body for transport vehicles produced in
accordance
with the method of the present invention. This van body is characterized by
walls
adjoining each other in a circumferential direction of the van body forming at
least one
angularly or U-shaped van body portion, and which consist integrally of a
thermoplastic
CA 02345298 2001-03-23
- g -
deformed flat piece having a supporting core with cover layers located at bath
its outer
sides, and in that the other adjoining edges of these and possibly further
walls are
interconnected especially in a thermoplastic manner.
Such as already described in part in connection with the method in accordance
with the
invention, the foreseen structure of the van body leads to substantial
advantages in
addition to the production also regarding the mounting to vehicles. Due to the
use of
sandwich plates the structure of the body displays a high st<~bility at a at
the same time
low weight, whereby the low weight benefits further by not needing the
otherwise
necessary mounting means such as connecting bars, edge b~~rs, screw bolts,
angle pieces
and similar. In comparison with van bodies of plywood the weight can be
reduced by
more than 50 %. For vehicles this means a considerable incn~ease of the
payload and thus
of the economy. Due to the thermoplastic integral connection of the materials
of the
walls of the body, the body structure is leak-tight and weatherproof.
A embodiment foresees that securing elements with a roughly spherical segment
shaped
supporting body of a thermoplastic material are foreseen, that the supporting
body
includes at its concave side a transverse pin consisting preferably of steel
and being
located at a distance from the bottom of the supporting body and is joined by
its
concave side in a thermoplastic manner to a wall of the van body and engages
thereby at
least at a zone into the wall.
Such securing bodies can be mounted at arbitrary places of the van body,
whereby also
here a thermoplastic welding connection is foreseen. For this, the supporting
body and
the place of the mounting to the wall can be correspondingly heated and the
joining is
made by pressing the two parts together. Such mounting bodies are especially
useful for
the securing of the cargo whereby in regard to this the mounting bodies are
expediently
placed in rows at the inner sides of opposite walls of the var.~ body and than
form
practically a replacement for the otherwise conventional securing rails.
A advantageous further embodiment of the invention foresees that the sandwich
plates)
comprises) one or more condensed zones as connecting points for a joining of
CA 02345298 2001-03-23
sandwich plates and/or for a joining to other parts, and that at these
condensed zones the
cover layers have relative to their by the supporting body caused initial
position being at
a distance from each other, a condensed position with a at IE:ast reduced
distance. The
van body features at these connecting zones a high stability .due to the
condensing by a
heat flow, so that a corresponding transmission of forces is possible. The
zones of the
joint form here within the compound system no weakened area and the excellent
strength properties of the sandwich plate and the van body formed therewith,
respectively, are effective thereby also at the total structure. It is hereby
also important
that the two cover layers are included in the zone of the joint and thus for
the
transmission of forces. Because the absorption of forces proceeds
substantially through
these cover layers, such is of a substantial importance for a lugh stability
in the
mounting and connecting zone.
The invention relates also to a device for practicing the method and also for
the
producing of a van body. This device is characterized in that it comprises a
support for a
multilayer sandwich plate consisting substantially of a thermoplastic material
including
a supporting core and at both sides thereof cover layers or a flat part formed
of one or a
plurality of joined sandwich plates and that the support has by at least one
of its edges a
heating zone.
By means of such a device it is possible to form by a specifically simple
procedure plate
shaped thermoplastic flat parts or similar which can be folded, whereby the
thermoplastic plate is positioned on the support in such a manner that it
rests by the
foreseen folding zone along the heating zone. When the heating zone is
activated, the
portion of the plate protruding over the heating zone can be folded in case of
a su~cient
heating. In a simplest case this occurs by the influence of gravity such that
as a rule
folding drives are not needed. If necessary the folding process can be
supported
manually.
A embodiment of the device according to the invention foresees that the
support is
formed substantially by a supporting frame which includes at least one
heatable tube
CA 02345298 2001-03-23
- g -
which can be heated at an edge for forming a heating zone. By means of this it
is
possible to realize a folding device with a minimum of expenditure. Regarding
its cross-
sectional shape and its position this heatable tube can be made to conform
with the
prevailing demands.
In order to produce parts with a plurality of folds it is advantageous if the
supporting
frame includes tubes located at edges and arranged advantageously in parallel
opposite
of each other which can be heated and of which the distance can advantageously
be
adjusted. By means of this thermoplastic plates can be folded simultaneously
at areas
located at a distance from each other.
it is preferably foreseen that the supporting frame is located within the
course of a
production line for van bodies and especially at a feeding table for a flat
part consisting
of one or several sandwich plates and bordered by a following conveyor with
rollers for
a transporting the partial van body away. Specifically in case of a series
production it is
possible to arrive therewith at very short cycle times with a corresponding
high
production output number.
According to a further embodiment of the invention the device may also
comprise a
pressing apparatus with pressing pads which can be heated and/or pressing
rollers which
can be heated and which preferably are placed at both sides at opposite areas
of the
joining zone of sandwich plates or flat pats in order to join edges of flat
parts or
sandwich plates which mate at the narrow sides.
By means of this pressing apparatus the zones of the joints :may be acted upon
under a
influence of heat in such a manner that at the one hand a integral
thermoplastic joint and
at the other side continuous planar outer surfaces are produced. Further, a
certain
condensing of the material occurs by the acting upon by pressure which leads
to a high
stability at the zone of the joint. There exists thereby, however, also the
possibility to
carry out the thermoplastic welding itself through integrated heating wires
and the
forming for planar, continuous outer surfaces by pressure pads or rollers.
Additional embodiments of the invention are set forth in the further dependent
claims.
Below, the invention will be described still more in detail regarding its
substantial
particulars with reference to the drawings.
CA 02345298 2001-03-23
-9-
There is illustrated schematically in:
Fig. 1 a perspective rear side view of a truck with a van body according to
the
invention,
Fig. 2 a flat part consisting of sandwich plates for producing a partial van
body,
Fig. 3 a device for a folding of a thermoplastic flat ;part to a U-shaped
partial
van body,
Fig. 4 a side view of two sandwich plates prepared to be connected to each
other,
Fig. 5 the sandwich plates illustrated in Fig. 4 in a state plugged into each
other
as well as pressure punches arranged at the areas of this connection zone,
Fig. 6 the two sandwich plates illustrated in Fig. 4 i,n a state in which they
are
welded together in a thermoplastic manner,
Fig. 7 a pressing apparatus with pressing pads for the connecting of sandwich
plates,
Fig. 8 a joined corner area,
Fig. 9 another embodiment of a corner joint,
Fig. 10 a sandwich plate with tubes inserted in the zone of foreseen folds,
Fig. 11 a schematic illustration of a device for folding sandwich plates with
tubes
integrated therein for the heat supply,
CA 02345298 2001-03-23
- 10-
Fig. 12 a partial view of a sandwich plate with a longitudinally slit tube
with
heating wires located at the edges of the slit , which is foreseen to be
placed at the zone of a foreseen folding,
Fig. 13 a sandwich plate having a longitudinally slit tube in a folded state
and
Fig. I4 a perspective illustration of a sandwich plate ,with a mounting zone
for a
mounting to a supporting element.
Fig. 1 illustrates in a perspective partial view the rear side of a truck with
a van body I .
The box shaped van body I illustrated in the embodiment includes two side
walls 2 and
3, a top wall 4 and a bottom, as well. The front wall located at the front end
of the van
body is not visible.
The van body or body is composed of several sandwich plates 6 (see also Fig. 4
to 6),
which consist of a supporting core 7 with outer covering layers 8. A plurality
of such
sandwich plates are combined to a flat part 2 (Fig. 2) from which the body is
produced.
The sandwich bodies consist at least to the largest part of a thermoplastic
material such
that they can be correspondingly deformed under a influence. of heat and a
flat part 9
such as for instance illustrated in Fig. 2 may be folded to a van body or
partial van
body.
As already mentioned above, the flat part is composed of several sandwich
plates 6.
Such sandwich plates 6 lend themselves to be produced in a predetermined width
practically endlessly, so that they may be placed adjoining each other either
extending
in the longitudinal direction of the body or, however, in its circumferential
direction and
joined together in order to form a suitable flat part 9.
The Figs. 4 to 6 illustrate a suitable joining method, whereby initially
according to Fig.
4 at the left sandwich plate a portion of the supporting core its removed for
forming a
receiving groove I O and from the other sandwich plate at its front end
portions of the
CA 02345298 2001-03-23
-11-
cover layers 8 are removed. The core area which has been fi.eed of the cover
layers 8 is
then inserted into the receiving groove 10, whereby the cover layers 8 overlap
each
other somewhat such as is schematically illustrated in Fig. 5. By aid of a
pressing device
11 which comprises heated pressing pads 12, 13 the zone of the joint 14 is
thereafter
acted upon by pressure and is heated, so that the ends of the: two sandwich
plates 6 set
into each other are welded together in a thermoplastic manner. The hot
pressure pads
12,13 are led together to a distance which corresponds to the thuckness of the
sandwich
plates, so that the zone of overlap of the cover layers is urged somewhat
towards the
inside and forms a slightly thickened zone 15 such as can be seen in Fig. 6.
By this
thermoplastic integral fusing flat parts 9 of any dimensions nnay be produced.
Especially
advantageous is thereby that no tosses of strength occur, so that practically
the same
properties regarding the stability are present over the entire :flat part .
Fig. 7 illustrates a pressing device 11 in a somewhat more detailed state
whereby it is
here specifically recognizable that the pressure pads 12 are rnounted on
pressing arms
16 which reach transversely over the sandwich plates) 6. Ait this embodiment
the
pressing pads 12 are equipped with pressing rollers 7 which are heated
electrically. In
this embodiment a additional material strip 18 is placed at the zone of the
joint onto the
joined zone 14 and welded in a thermoplastic manner to the two sandwich plates
6
which are to be joined. The material strip 18 which is fed for instance from a
supply
roll I9 can consist specifically of the same material which is also used for
the cover
layers 8. By the hot pressing together by aid of the pressure pads 12 or the
pressure
rollers 17, respectively, also here a condensing of the materi,~l can occur
insofar in that a
continuous flat surface is arnved at.
The two sandwich plates to be connected together and the pressing device can
be
positionable either step wise or continuously relative to each other along the
joint 14. It
is preferably foreseen that the sandwich plates 6 rest stationa~.ry on a
support and that the
pressing device 11 is positioned.
In order to form the van body initially and as described above, a flat part 9
such as for
instance illustrated in Fig. 2 is assembled from sandwich plates 6. This flat
part 9 can
CA 02345298 2001-03-23
- i2 -
then have a circumferential shape which corresponds to the development shape
or partly
developed state shape of the van body. In the embodiment according to Fig. 2
the flat
part 2 includes the two longitudinal walls 2 and 3, the roof wall 4 and a end
wall 20. For
sake of clearness the borders of the individual walls are illustrated by
broken lines
which also form the folding lines when shaping the van body.
By means of the flat part 9 illustrated in Fig. 2 a partial body of a U-shaped
cross
section with a front end wall 20 can be formed, which then still must be
joined to the
bottom 5 in order to obtain a van body 1 in accordance with Fig. 1. There
exists,
however, the possibility that additionally bottom sections adjoin at the
outside the
longitudinal edges of the side walls 2 and 3, so that after thE; shaping of
the van body
merely a longitudinal joint zone 14 is present in the bottom area (Fig. 1).
A device for a forming of a flat part 9 to a van body or partial body is
illustrated in Fig.
3. This device 21 comprises a support 22 with heating zones 23 located along
its edge
areas. In this embodiment the support is designed table like with a supporting
frame 34,
whereby the height of the support according to the arrow Pfl and also the
distance
between the two heating zones 23 are preferably adjustable in accordance with
the
double arrow Pfl. By means of this a adjusting of the device to variously
dimensioned
van bodies is made possible.
in the embodiment according to Fig. 3 a rectangular flat part 8 is fed to the
device 21
whereby it is positioned in such a manner that it comes to lie with the areas
of the
intended fold 25 on the heating zones 23. By an activating of the heating
zones 23 the
areas of the flat part 9 resting thereupon are heated and can be bent
downwards merely
due to the force of gravity or, however, additionally aided manually.
The device 21 with the supporting frame 24 and the upper support is arranged
in the
embodiment within the course of a production line. A feeding table 26, which
is
designed here as a roller conveyor is utilized for the feeding.. This feeding
table 26 can
be moved for a passing on of the flat part 9 to the support 22 towards same in
accordance with the arrow Pf3 and for the folding process it: can be moved
back
according to the arrow Pf4 at Ieast by the distance of the of the flat part 9
projecting
CA 02345298 2001-03-23
-13-
beyond the heating zone facing the feeding table 26. Thus, a free space is
then produced
such that also at the le$ side a portion of the flat part 9 can be folded
downwards. After
the folding process a U-shaped partial body I a is available which can be
transported off
by means of a roller conveyor 27 adjoining the device 21 fo:r a further
processing.
In the embodiment heatable tubes 28 are foreseen in the heating zones 23
arranged at
edges at the supporting frame of which the distance from each other and also
their
height position may be adjusted in accordance with the doulble arrows Pfl and
Pf2. The
cross section of the heatable tubes and, thereby, specifically their surfaces
which come
to contact the flat part 9 may be designed variously depending from the
respective
required radiuses of the fold or the foreseen deformations, respectively. The
tubes 28
may be heated electrically or a liquid could be made to flow through same when
formed
as hollow tubes.
In Fig. 3 the hollow tubes 28 which can be heated are connected through pipes
for
liquids to a heating device. It also shall be mentioned that a folding
abutment which can
be set for various folding angles may be located under the fi.~bes which can
be heated.
There exists, furthermore, the possibility to equip the folding device 21 with
further
tubes 28 which may be heated, in order to produce besides the doubly folded
van body
illustrated in Fig. 2 also four times folded van bodies with bottom parts
formed directly
thereon. Furthermore, further heatable tubes may be foreseen which are
oriented
transverse to the illustrated heatable tubes 28 in order to undertake a
folding of end
walls 20 (see Fig. 2).
In order to join the corner edges, cover layers which project at an edge of
the one wall
are joined in a thermoplastic fashion to the supporting core and/or to the
cover layers of
the other wall. The Figs. 8 and 9 illustrate somewhat schematically such
corner joints
which Iead to a high stability. According to Fig. 8 respective cover layers 8
of one
sidewall 3 which project beyond the supporting core 7 are folded at the front
end and
placed on top of each other, and the joining end for instance; of a front wall
20 which
has been prepared in the same way set into the angle of the fold formed
thereby. In this
position then, a thermoplastic welding of the parts which contact each other
takes place
by means of pressure pads and under the influence of heat and pressure.
CA 02345298 2001-03-23
-14-
Fig. 9 illustrates a corner joint at which only the one wall 3 lhas cover
layers 8 which
project beyond the supporting core 7 and of which one is folded over the front
end at a
right angle and the other one is guided loop like onto the other side of the
front wall 20.
Also here the joining of the material takes place under the influence of heat
and
pressure.
At the van body 1 illustrated in Fig. 1 a flat part has been used which
includes the two
side walls 2 and 3, the top wall 4 and also the bottom 5. The; bottom is
thereby
completed of two half parts which are welded at the center in a thermoplastic
manner
such as is illustrated by the Figs. 4 to 6.By means of this a v,an body is
formed which is
practically integral in the direction of the circumference, whiich has
homogeneous
strength properties.
In order to mount a rear wall or a rear door a portion of the supporting core
can be
removed at the rear circumferentially extending end wall for obtaining a
receiving
groove, and a end profiled bar, for instance a squaxe tube made of aluminum or
a plastic
material set into the groove and mounted thereto. Hinges fo:r doors which
consist
preferably also of sandwich plates 6 can then be mounted to this end bas.
There exists,
however, also the possibility that for producing a hinge between two walls of
the van
body which are to be pivotally connected (side walls 2 and 3 and wings of
door) to
provide these walls at their longitudinal edges which face ea~;,h other
possibly with tubes
set in at those edges and preferably welded in a thermoplastic manner into
same, with
recesses staggered in the longitudinal direction. The respective remaining
edge portions
of the other side engage into these recesses and than a hinge bolt can be
stuck into the
edges which mesh with each other.
As indicated in Fig. 1, the van body is connected by aid of screw bolt
connections 30 to
a supporting frame 32 of the motor vehicle which is depicted with broken
lines. In the
floor 5 condensed areas 31 (see also Fig. 14) produced by a deformation by
heat are
foreseen at the mounting area for forming joining points, each including a
central hole
33 for receiving a screw bolt 34 extending there through. Due to the
thermoplastic
CA 02345298 2001-03-23
-15-
condensing at the connecting area the two cover layers S can be kept and are,
therefore,
included regarding the transmission of forces. This leads to a high stability
at the
connecting zone and a practically continuous transition of a flow of forces.
Material,
which is located adjacent the condensed zone because it has been driven to
that zone
adds to mentioned fact. Fig. 14 does also depict that a interrnediate plate 41
for a
distribution of forces is inserted between the bottom 5 and tile supporting
frame 32 (of
which only one single beam is illustrated). Condensed areas 'with cutouts
formed in
these areas can also be foreseen for the inserting of window:., hatches, doors
or similar.
Fig. 10 and 11 illustrate a embodiment of a sandwich plate or flat part 9
formed from
same. Two thermoplastic tubes 35 located at a distance frorr~ each other are
placed here
in the zone of foreseen folds which may be heated for a folding of the flat
part. For this
there is the possibility to temporarily place heating rods into the tubes for
the folding
operation. Furthermore, there is also the possibility to have heated air
flowing through
these tubes.
The inserted tubes 35 consist preferably also such as is the case of the other
elements of
the sandwich plate 6 of a thermoplastic material such that there is no
detrimental effect
regarding a recycling. For the folding process as such the flat part 9 can be,
such as is
shown in Fig. 11, placed onto a support 22 which has such dimensions, that the
fold
areas with the integrated tubes 35 come to rest at the longitudinal edges of
the support
22.
Instead of a tube which is closed completely along its circumference, such as
illustrated
in Fig. 10 and 11 it is also possible to foresee in the zone of a intended
fold a tube 36
which is slit at the inner side of the fold (fig. I2 and 13), whereby a
heating wire 37 is
inserted in at least one of the edges of the slit. The open dist2~nce between
the edges of
the slits corresponds in the not deformed state (Fig. 12) to about the
foreseen angle of
the fold and dimensioned such that at the foreseen angle of the fold the edges
of the slit
contact each other. In this position the heating wire is then a<;tivated and
the edges of
the slit weld together so that the tube is closed along its entire
circumference, forms a
stabilizing element and reinforces additionally the zone of the joint. Fig. 13
illustrates a
CA 02345298 2001-03-23
-I6-
flat part 9 and cut-out, respectively, of the van body which :has been formed
under
influence of heat and is reinforced by the welding together of the edges of
the tubes.
It also shall be mentioned, that the tubes 35 illustrated in the Figs. 10 and
1 l and also
the slit tube 36 illustrated in Fig. 12 and 13 can consist of a sandwich
material.
The inserted tubes 35, 36 can also be used as installation tubes, for instance
electrical
conduits for the illumination system of the vehicle may be placed in these
tubes.
At the inner side, at the side walls 2 and 3 of the van body, also a row of
securing
elements 38 for bracing belts 39 can be arranged such as can be seen in Fig.
1. These
securing elements 38 consist of a roughly dish shaped supporting body
consisting of a
thermoplastic material which comprises at its concave side a transverse pin 40
arranged
at a distance from the bottom of the supporting body and welded at its convex
side to
the inside to the side wall of the van body in a thermoplastic; manner. At the
thermoplastic welding to the respective wall area of the van body the securing
elements
38 are pressed somewhat into the wall which has softened after the heating.
Therefore,
no additional mounting elements for a mounting of the securing elements 38 to
the wall
are needed. Hooks which are arranged at the end of the bracing belts 39 can be
hooked
on at the transverse pin 40.
It also shall be mentioned that directly with the producing of the sandwich
plates or the
flat part 9, respectively, consisting of such plate a outer protection layer
is lacquered
onto the plate which leads to a Long life time and a resistance against IJV-
rays.
CA 02345298 2001-03-23
17
In summarizing, following advantages are arrived at, among others, by the
present
invention:
Simplification of the assembly and, thereby, considerable time savings;
no drilling and welding processes needed for assembling;
saving of weight down to 1/3 to 1/4 of previous weights and therewith
a considerable higher cargo loading capabilit~i;
only one kind of material and therewith improved environmental
compatibility;
extremely weather proof;
no sealing problems;
suitable in connection with foodstuff.
