Note: Descriptions are shown in the official language in which they were submitted.
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HIGH-RIGIDITY PANEL
FIELD OF THE INVENTION
The present invention relates to a high-rigidity panel of lightweight
having a high rigidity to be applied to floor or wall surfaces of such
structures
as building structures, airplanes and vehicles.
DESCRIPTION OF THE PRIOR ART
Heretofore, as structures for use as panels of such structures as
building structures, airplanes and vehicles, those of a honeycomb structure
are
very popular. Metals are mainly used as a constituent material of a
honeycomb structure. The thickness of a metal used for the honeycomb
structure is very small, in the range of about 50 ,u m to about 100 ,u m.
However, since the honeycomb structure has the function of dispersing the
load applied thereto, the panel of the honeycomb structure has the feature
that
it is very strong despite of lightweight.
However, for fabricating a panel of such a honeycomb structure, it is
necessary to go through many manufacturing steps like ~1 adhesive
application ~ ~ plate cutting ~ ~3 laminating ~ ~ pressing -~ 5~
cutting. Besides, due to accumulation of losses in those manufacturing steps,
the waste of the structural material used becomes large. Furthermore, from
the standpoint of productivity, for example at the time of bonding a honeycomb
structural member and surface members to one another, so that the surface
members cover both sides of the honeycomb structural member, it is necessary
that these members after being cut be fixed at predetermined shape and size
during the bonding operation. But such a bonding operation is troublesome,
giving rise to the problem that the working afficiency is limited and that the
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productivity is deteriorated markedly.
For solving the above-mentioned problems involved in the panel of the
honeycomb structure, a metallic panel of lightweight having a strength high
enough for use as a structure wall panel and superior in productivity is
proposed in Japanese Patent Application Laid-Open (kokai) No. 6-316015.
FIG.l is a partially cut-away view in perspective of the metallic panel,
proposed in the above patent application. This metallic panel, indicated at 7,
comprises a structural member 9 with a large number of convex portions 8
formed thereon and surface members 10 bonded to both sides of the structural
member 9. In an intermediate layer 11 of the metallic panel are formed a
large number of independent cellular portions 12 and continuous spatial
portions 13. Since this metallic panel has a large number of cellular portions
in its intermediate layer, it is possible to disperse an applied load as is
the case
with a panel of the honeycomb structure, and hence the metallic panel can
exhibit a high strength against the applied load. In panel manufacture,
moreover, it is possible to adopt a simple process comprising the steps of
subjecting a thin metallic material, such as aluminum to deep drawing or
bulging to form a large number of convex portions, and subsequently bonding a
surface material to both sides of the thus processed metallic material. For
the
proposed metallic panel, however, no consideration is given to its rigidity
against flexural deformations. Thus, the metallic panel in question involves
the problem that it is markedly deficient in rigidity
FIGS.2 and 3 show how the above metallic panel is deformed under the
application of a load, of which FIG.2 shows a deformed state of the panel
under
the application of a distributed load p in a stable state of the whole
underside
of the panel being supported, and FIG.3 shows a deformed state of the panel
under the application of the distributed load p in a both end-supported state
of
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only end portions of the panel underside being supported.
As shown in FIG.2, when the distributed load p is applied to the
metallic panel in a stable state of the panel underside, the panel can exhibit
a
high strength. However, as shown in FIG.3, in a both end-supported state of
the panel in which only both end portions of the panel underside are
supported,
the panel is subjected to bending due to the distributed load p. In this case,
since the metallic panel is provided with the convex portions 8 in a separated
manner at predetermined constant intervals, the portions of the surface
members 10 supported by the convex portions 8 are not deformed, whereas the
surface member portions located between adjacent convex portions 8 and not
supported by the convex portions are apt to be deformed. Once deformations
occur at portions of the surface member 10, the panel as a whole easily
undergo flexural deformations, thus giving rise to the problem that the
rigidity
of the panel is insufficient as a structural product.
OBJECT OF THE INVENTION
For panels to be used as floor or wall surface panels of such structures
as building structures, airplanes and vehicles, it is required to exhibit a
high
rigidity as a structural product so as not to cause flexural deformations
irrespective of how the panels are supported and no matter in what state a
load may be applied to the panels, in addition to the requirement that the
panels should be lightweight.
Taking note of the improvement of rigidity out of the performances
required for floor or wall surface panels of a structure, in order to prevent
flexural deformations of the panels, the present invention intends to provide
a
panel having a high rigidity
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SI:f~IARY OF THE INVENTION
Having made various studies about the rigidity of panels, the present
inventors made it clear that in the both end-supported state of the foregoing
conventional metallic panel with only end portions of the panel underside
being supported, the surface member portions located between adjacent convex
portions and not supported by the convex portions are easily subjected to
flexural deformations, and that the rigidity of the panel as a whole is
deteriorated markedly Having made further studies, the present inventors
found out a panel structure in which flexural deformations are diminished
even when a load is applied to the panel in the both end-supported state of
only both ends of the panel underside being supported. In this way we
completed the high-rigidity panel of the present invention.
The gist of the present invention resides in the following panel, an
example of which is shown in FIG.4 to be referred to later: "a high-rigidity
panel having a laminated structure in which two or more panels each having a
large number of convex portions are superimposed together, with the convex
portions of each panel being bonded to one or more convex portions of the
other
panel adjacent thereto."
The "laminated structure" as referred to herein, means a laminated
panel structure in which panels each having a large number of convex portions
are bonded together through the respective convex portions. The material of
the panel according to the present invention is not specially limited. Not
only
steel but also aluminum (Al) and titanium (Ti) are also employable.
Aluminum and titanium not only ensure the required strength of the panel,
but also are more advantageous to the reduction in weight of the panel.
Further, the use of the panel according to the present invention, is not
limited
to floor or wall surfaces of building structures. The panel of the present
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invention is also applicable to airplanes and vehicles.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG.1 is a partially cut-away view in perspective of an example of a
conventional metallic panel;
FIG.2 shows a deformed state of the conventional metallic panel under
the application of a distributed load to the panel in a stable state of the
whole
panel underside being supported;
FIG.3 shows a deformed state of the conventional metallic panel under
the application of a distributed load to the panel in a both end-supported
state
of only both end portions of the panel underside being supported;
FIG.4 is a partially cut-away view in perspective of a construction
example of a high-rigidity panel according to the present invention;
FIG.5 shows a flat top of each convex portion formed on each of
constituent panels of the high-rigidity panel according to the present
invention; and
FIG.6 shows a flat top, with an aperture formed therein, of each convex
portion formed on each of constituent panels of the high-rigidity panel
according to the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
As mentioned above, the reason why the conventional metallic panel is
deficient in rigidity, is that flexural deformations occur at the surface
member
portions located between adjacent convex portions and not supported by
convex portions. This is because generally the convex portions exhibit a high
resistance to deformations, whereas the surface members are low in their
resistance to deformations. In other words, if such deformations of the
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surface members can be suppressed, it is possible to obtain a panel having a
high-rigidity. This condition can be satisfied, if the convex portions of each
constituent panel are bonded not only to the associated surface member, but
also to the convex portions of another constituent panel. Therefore, if the
convex portions that exhibit a high resistance to deformations of the panels,
are bonded together, it is possible to suppress deformations under the
application of a load to the panels, resulting in that the laminated panel as
a
whole can exhibit a high-rigidity.
FIG.4 is a perspective view with parts partially cut-away to show an
example of construction of a high-rigidity panel according to the present
invention. The high-rigidity panel of the present invention, indicated at 1,
is
of a laminated structure (a laminated panel) comprising two or more panels 3
superimposed together and each having a large number of convex portions 2.
The panels 3 are bonded together through the respective convex portions 2 to
constitute a panel laminate 5, and one or both sides of the panel laminate 5
are
covered with surface members 4. In this case, the convex portions 2 of each
panel 3 are bonded to the convex portions 2 of another panel 3. Therefore,
even when a load is applied to the laminated panel in a both end-supported
state of only both ends of the panel underside being supported, panel
deformations are small and a high-rigidity is ensured as the entire panel
structure.
The number of another convex portion to which a specific convex
portion is bonded may be at least one. For example, assuming that the panel
laminate of the present invention is constituted by two panels A and B, the
convex portions of panel A may be bonded respectively to the convex portions
of
panel B in 1:1 relation, or each of the convex portions of panel A may be
bonded to two or more convex portions of panel B and, also when viewed from
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the panel B side, each of its convex portions may be bonded to two or more
convex portions of panel A. The larger number of convex portions of panel B
to which one convex portion of panel A, the more dispersed is the load applied
to the A-B panel laminate, so that the resistance to deformation increases and
the rigidity of the entire panel structure is enhanced.
FIGS.5 and 6 are perspective views showing examples of convex shapes
in the panel laminate of the present invention, with no special limitation
being
imposed on the shape of convex portion. Usually, each convex portion
assumes an inverted bowl shape, as shown in FIGS, the upper end of which is
preferably flat to enhance the effective bonding with another convex portion
or
a surface member. The size and shape of each convex portion may be
determined according to the place where the panel structure is to be used, the
purpose of use, etc. As shown in FIG.6, the flat top of the convex portion may
partially be formed with an aperture for facilitating a molding operation.
Even in this case, there is no fear of deterioration in strength or rigidity
of the
resulting panel laminate for use, as a floor or wall surface panel in such a
structure as a building structure, an airplane, or a vehicle.
The number of constituent panels of the panel laminate according to
the present invention, is usually two. However, even where the number of
constituent panels is three, for example, A, B and C, if convex portions are
formed on one sides of panels A and B, and convex portions are formed on both
sides of panel C, and if panels A and B are disposed so that their convex
portions are opposed to each other, with panel C being sandwiched in between
both panels A and B, the convex portions of panel A are bonded to the convex
portions formed on one side of panel C, and at the same time the convex
portions of panel B are bonded to the convex portions formed on the other side
of panel C. Thus, the number of constituent panels may be three. By
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increasing the number of constituent panels, it becomes possible to thicken
the
resulting panel laminate. Besides, not only the dimensional range as a
structural material can be widened, but also it is possible to expect the
improvement of rigidity and of heat insulating property
As described above, the panel laminate of the present invention has a
surface member or members, e.g. particle board, on one or both sides thereof.
Like a panel of the honeycomb structure, the panel structure of the present
invention exhibits the function of dispersing a load applied thereto. Besides,
the panel laminate of the present invention is high in strength, and the
convex
portions of the constituent panels are bonded together, so it is little
deformed
and exhibits a high-rigidity as a whole.
As to the material of the high-rigidity panel of the present invention,
there is no special limitation. In the case of using steel, there is adopted
any
of steel plates, various plated steel plates and pre-coated steel plates. As
noted previously, other metallic materials may be used such as, for example,
aluminum and titanium or various resins may be used. The use of aluminum
or titanium not only contributes to the enhancement of rigidity, but also is
more advantageous to the reduction in weight of the resulting panel.
For fabricating the high-rigidity panel of the present invention, if a
metal is used as the material of the panel, the metal is usually as thin as
100
to 1200,um and is subjected to deep drawing or pressing to form convex
portions at predetermined positions, then, for example, two of the panels thus
formed are bonded together through the respective convex portions to afford a
panel laminate. Next, a surface member or members are applied to one or
both sides of the panel laminate. In the case of using a resin as the material
of the panel, it becomes possible to attain a further reduction of weight and
facilitate molding, in comparison with the use of a metal.
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The bonding between convex portions may be in a relation of 1:1 or
even in a relation of 1:2 or more. In 1:1 bonding, both convex portions may be
aligned exactly with each other or may be somewhat deviated from each other.
By such "off center" of convex portions the deformation suppressing effect is
enhanced and hence there is attained a further improvement of rigidity In
the case of 1:2 or more bonding, the bonded convex portions are off center
with
respect to each other as a matter of course.
The bonding between convex portions may be done by an adhesive
bonding using, for example, urethane resin or epoxy resin, or may be done by
welding, such as spot welding. In the case of an adhesive bonding or a
combination of adhesive bonding and welding, the resulting panel laminate is
superior in its impulsive sound absorbing performance, in comparison with the
case where only welding does the bonding.
As to the bonding of surface members to the upper and lower surfaces
of the panel laminate, it may be done by adhesive bonding or using machine
screws.
The above processing comprises relatively simple steps that are
repeated. Besides, the processing can be done continuously from a long
material, which is in a wound-up state. Thus, the processing in question is
also superior in productivity.
EXAMPLES
The high-rigidity panel 1 of the present invention, shown in FIG.4, was
fabricated. As each panel 3 there was used a cold-rolled steel plate
(thickness: 600 ,u m), which was pressed to form convex portions (bottom
diameter: 250 mm, height: 45 mm) of such a shape as shown in FIGS, so as to
give a center-to-center distance of 350 mm between the bottoms of adjacent
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convex portions 2. Thereafter, two such panels 3 were laminated together to
form a panel laminate 5, and surface members (particle boards) were axed
respectively to the upper and lower surfaces of the panel laminate 5 to afford
the high-rigidity panel 1. Bonding between convex portions 2 was done by
spot welding, and the a~xation of the surface members 4 to the upper and
lower surfaces of the panel laminate was done using machine screws. In the
panel laminate of panels 3, the convex portions 2 of the lower panel 3 are in
1:1
correspondence to the convex portions 2 of the upper panel 3, but the convex
portions 2 are somewhat off centered with respect to one another.
The high-rigidity panel thus fabricated according to the present
invention was checked for rigidity under the application of various loads
(e.g.
distributed load and local load). As a result, it turned out that panel of the
present invention exhibited a high-rigidity as a whole, with suppressed
flexural deformations, even in such a both end-supported state, as shown in
FIG.3, in which only end portions of the panel underside were supported.
Thus, the high-rigidity panel of the invention is superior in both strength
and
rigidity and is lightweight, thus is suitable for use as a floor or wall
surface
panel of a structure for example.
