Freight floor, freight container, use of a multilayer panel to produce a freight floor, and method for producing a freight floor

Abstract

A freight floor having a multilayer construction and that is formed as a composite material, comprising a core layer of carbon-fiber-reinforced and/or glass-fiber-reinforced plastic and a seating layer of a metal alloy, in particular an aluminum alloy.

Claims

1. A freight floor comprising: first and second core layers of fibre-reinforced plastic, a foam layer arranged between the first core layer and the second core layer, the foam layer including foam and a plurality of cavities in the foam layer, a seating layer of a metal alloy, wherein one of the core layers and the seating layer are connected together by material fit and/or by form fit, wherein the foam layer comprises foam and a supporting structure made of synthetic resin, the supporting structure being formed in the cavities of the foam layer and extending vertically to the freight floor and firmly joining the first and second core layers, the synthetic resin of the supporting structure joining the first core layer and the second core layer by material fit, wherein the foam has a low density and is at least partially saturated with the synthetic resin to reinforce the freight floor.

2. The freight floor of claim 1, wherein the first core layer and the second core layer of fibre-reinforced plastic each comprise a fibre network of carbon fibres.

3. The freight floor of claim 1, wherein the foam layer has a thickness of 1.0 to 8.0 mm.

4. The freight floor of claim 1, wherein the seating layer comprises an aluminum metal alloy having a thickness of 0.5 mm to 2.5 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described below with reference to several embodiment examples which will be explained in more detail with reference to drawings. The drawings show:

(2) FIG. 1 a diagrammatic view of a freight container with a floor plate and side walls;

(3) FIG. 2 a cross section through the floor plate in FIG. 1;

(4) FIG. 3 a three-layer embodiment of the floor plate from FIG. 1;

(5) FIG. 4 a cross section of an edge region of the freight container from FIG. 1;

(6) FIG. 5 a cross-section through an alternative embodiment of the floor plate (single-layer core with connecting layer); and

(7) FIG. 6 a cross-section through an alternative embodiment of a floor plate (multilayer core with connecting layer).

DESCRIPTION

(8) In the description which follows, the same reference numerals are used for parts which are the same and parts which have the same effect.

(9) FIG. 1 shows a cuboid freight container 10 having a freight container height h, a freight container width b and a freight container length 1.

(10) The freight container 10 has a floor plate 20 which is arranged opposite a cover plate 13 and can be regarded as an embodiment of the freight floor according to the invention. The casing surface of the cuboid freight container 10 is formed by the side walls 12a to 12d, in particular a first side wall 12a, a second side wall 12b, a third side wall 12c and a fourth side wall 12d. The side walls 12a to 12d are arranged in pairs opposite each other.

(11) FIG. 2 shows a cross-section through the floor plate 20 of the freight container 10. In the embodiment example shown in FIG. 2, the floor plate 20 has a multilayer structure with a seating layer 21 and a core 40. The seating layer 21 forms the bottom layer and is connected flush with the core 40 by material connection, wherein the core lies on the seating layer 21. The floor plate 20 is constructed as a composite material, wherein the core 40 consists of a core layer, namely a CFRP layer 42 (carbon-fibre-reinforced plastic), and the seating layer 21 consists of an aluminium alloy (e.g. a material known as 7075 T6 or 2024 T3/T4). The seating layer 21 has a seating layer thickness h1 of 1 mm and the CFRP layer 42 has a core layer thickness h2 of at least 2 mm. Preferably the aluminium alloy has a strength of at least 500 N/mm.sup.2. With this construction, it is possible to achieve a weight reduction of the floor plate 20 of around 35% to 50%, wherein existing requirements (e.g. good force connection with rollers of freight transport devices, high stability) are fulfilled. Since the majority of the weight of a conventional freight container 10 still lies in the floor plate 20, the overall weight is thus significantly reduced. On transport of the freight container 10 by aircraft, this leads to a significant fuel saving which again results in lower CO2 emissions.

(12) FIG. 3 shows a further embodiment example of the floor plate 20 which is made of three layers. In a sequence from top to bottom, this floor plate 20 has a wearing layer 23, a core 40 consisting of a CFRP layer as a core layer, and a seating layer 21. The wearing layer 23 can be made of glass-fibre-reinforced plastic or aramide. The seating layer 21 is made of a metal alloy, preferably an aluminium alloy. A wearing layer thickness h3 amounts to around 0.25 to 0.5 mm, while the core layer thickness h2 is around 3 mm and the seating layer thickness h1 around 1 mm.

(13) This design of the floor plate 20 as a sandwich panel has the advantage that the at least one core layer (e.g. CFRP layer 42) is protected by the wearing layer 23. Furthermore the multilayered structure leads to an increase in stability of the entire floor plate 20. In a further embodiment example, the wearing layer 23 can also be made of aluminium alloy, e.g. 7075 T7 or 7075 T6. Theoretically a steel plate can also be used, wherein however an electrically non-conductive layer is preferred since this has no influence on any RFID tag 14 (see FIG. 1) which may be provided on or in the freight container 10.

(14) The floor plate 20 according to the invention preferably has a peripheral floor plate profile 25 (FIG. 4) which can be inserted in a container corner profile to attach the floor plate 20 to the side walls 12a to 12d. Therefore no additional fixing means, e.g. a weld connection or rivets, is required.

(15) The freight container 10 according to the invention preferably has a floor plate 20 which is equipped with a seating layer 21 on the bottom that is made from a metal alloy, in particular an aluminium alloy. This means that existing freight decks of aircraft with corresponding freight transport devices can be used to transport the freight containers 10 without problems relating to the coefficient of friction on action of the rollers provided. The freight containers 10 according to the invention can therefore be used universally.

(16) Preferably the floor plate 20 is also formed in at least two layers, in particular three layers, and as a composite material or laminate. The individual layers, in particular the seating layer 21 and/or the core layer and/or the wearing layer 23, are connected together by material or form fit, wherein a material fit connection is preferred. A connection between the individual layers can be created directly or indirectly.

(17) In the embodiments described, the cuboid embodiment of the freight container 10 has been discussed in detail. For the person skilled in the art, it should be evident that the form of the freight container 10 is given merely as an example and can be arbitrary. Common freight containers 10 have a chamfer in the upper region in order to adapt optimally to the cargo hold of an aircraft.

(18) Further embodiment examples of the cargo hold floor 20 according to the invention are shown in FIGS. 5 and 6.

(19) FIG. 5 shows a cargo hold floor 20 which has a core 40 and a seating layer 21 of aluminium alloy. The core 40 is made from a CFRP layer 42 and is connected to the seating layer 21 via a rubber layer 47. The rubber layer 47 can be glued to the CFRP layer 42 and/or the seating layer 21. A PU adhesive could also be used. Alternatively, the rubber layer 47 can be vulcanised onto the seating layer 21 and/or the CFRP layer 42.

(20) A further embodiment example is shown in FIG. 6. The core 40 in this example is made multilayered and connected to the seating layer 21 via a rubber layer 47 as a connecting layer. The core 40 comprises a foam layer 43, wherein on alternate sides of the foam layer 43 can be arranged a first CFRP layer 42 and the second CFRP layer 44. The foam layer 43, the first CFRP layer 42 and the second CFRP layer 44 are glued together by a synthetic resin. Preferably the foam layer 43 has honeycomb-shaped cavities which allow the hardened synthetic resin to create a direct material connection between the first CFRP layer 42 and the second CFRP layer 44. To this extent, the foam layer 43 encased by the CFRP layers 42, 44 is particularly suitable for absorbing vertical loads, without this leading to a compression of the core 40. The hardened synthetic resin in the cavities of the foam layer 43 thus forms a supporting structure 49. A GFRP layer 41 is arranged on the side of the first CFRP layer 42 facing away from the seating layer 21. This GFRP layer 41 can be a wearing layer 43 which protects the first CFRP layer 42 from wear. It is possible to glue the GFRP layer to the core 40 during its production.

(21) The CFRP layer 42 can have a first network of glass fibres and the first CFRP layer 42 can have a second network of plastic fibres, wherein the fibres of the first network are arranged at a 45° angle to the fibres of the second network. Therefore the following structure could result: +45/−45° GFRP layer, 0/90° CFRP layer, foam core (e.g. Rohacell), 0/90° CFRP layer.

(22) The first CFRP layer 42 can for example have thickness of 0.2 mm to 0.6 mm, in particular 0.4 mm. The foam layer 43 can have a thickness of 1.0 to 8.0 mm, in particular 1.8 to 6.0 mm. The second CFRP layer 44 can have similar or identical thickness conditions to the first CFRP layer 42. The seating layer 21 in the embodiment example shown has a thickness of 1.0 to 1.5 mm and consists of 2024 T3.

(23) In one embodiment example, a metal layer e.g. of aluminium is arranged on both sides of a core, e.g. a core 40, as described above. The layers can be connected together by gluing and/or vulcanizing. This sandwich arrangement has the advantage that the floor plate 20 only deforms slightly under temperature fluctuations. The production process is also simple, since the seating layer 21 and the wearing layer 23 of metal or a metal alloy can be connected to the core 40, e.g. glued, in one production step. In one embodiment example, the layers can be connected at a temperature (e.g. greater than 20°, greater than 30°, greater than 40°).

(24) The embodiment of a freight container and the floor plate 20 used therein have been described above. According to the invention, a method is also provided for production of a corresponding floor plate 20 or a freight container floor, and a production method for production of a freight container 10. For example, a method for production of a freight container floor can comprise the following steps: Production of the core layer 22 of carbon-fibre-reinforced and/or glass-fibre-reinforced plastic; Production of a seating layer 21 of a metal alloy, in particular the aluminium alloy described above; Connection of the seating layer 21 with the core layer 22 by material connection and/or by material fit.

(25) Said production steps can take place before the layers are connected. Theoretically however it is also conceivable first to produce one of the layers and then to construct the further layer on this base layer. For example the aluminium alloy can form the base layer on which the core layer 22 with the carbon-fibre reinforcement and/or glass-fibre reinforcement and/or aramide-fibre reinforcement is produced successively.

(26) Furthermore in the method according to the invention, a wearing layer 23 can be applied. Here again it is possible first to produce the seating layer 21, the core layer 22 and the wearing layer 23, and then create a material fit connection between the individual layers. Alternatively the seating layer 21 and the wearing layer 23 can be produced, and the core layer 22 constructed successively on the seating layer 21 and/or the wearing layer 23. The composite material can be formed by joining together the seating layer 21 with or without core layer 22, and the wearing layer 23 with or without core layer 22.

(27) It should be evident to the person skilled in the art that numerous alternative embodiments exist for the production method. Similarly it should be evident to the person skilled in the art how a freight container 10 according to the invention can be produced. Furthermore the person skilled in the art should know how to produce the freight floor as part of a freight pallet.

(28) A plurality of embodiments are described below for implementing the invention.

Embodiment 1.1

(29) Freight floor comprising:

(30) a core layer 42, 43, 44 of carbon-fibre-reinforced and/or glass-fibre-reinforced and/or aramide-fibre-reinforced plastic, and

(31) a seating layer 21 of a metal alloy, in particular an aluminium alloy, wherein the core layer 42, 43, 44 and the seating layer 21 are connected together by material fit and/or by form fit.

Embodiment 1.2

(32) Freight floor according to embodiment 1.1,

(33) characterised in that

(34) the seating layer 21 has a thickness h1 of 0.5 mm to 2.5 mm, in particular 0.7 mm to 1.5 mm, in particular 0.9 mm to 1.5 mm.

Embodiment 1.3

(35) Freight floor according to any of the preceding embodiments,

(36) characterised in that

(37) the seating layer 21 has a strength of more than 400 N/mm.sup.2, in particular more than 500 N/mm.sup.2.

Embodiment 1.4

(38) Freight floor according to any of the preceding embodiments,

(39) characterised by

(40) a wearing layer 23 or top layer which is arranged on the side of the core layer 42, 43, 44 facing away from the seating layer 21, wherein the wearing layer 23 and the core layer 42, 43, 44 are preferably connected together by material fit and/or by form fit.

Embodiment 1.5

(41) Freight floor according to any of the preceding embodiments, in particular embodiment 4,

(42) characterised in that

(43) the wearing layer 23 is formed from a metal alloy, in particular an aluminium alloy, and/or a glass-fibre-reinforced plastic and/or a material from the group of aromatic polyamides.

Embodiment 1.6

(44) Freight floor according to any of the preceding embodiments

(45) characterised in that

(46) at least one of the aluminium alloys is an aluminium wrought alloy with the main alloy element zinc, in particular with 0.7 to 13.0% zinc, in particular 0.8 to 12.0% zinc.

Embodiment 1.7

(47) Freight floor according to any of the preceding embodiments

(48) characterised in that

(49) at least one of the aluminium alloys is an aluminium alloy with a solution annealed and/or artificially aged and/or overhardened heat treatment.

Embodiment 1.8

(50) Freight floor according to any of the preceding embodiments,

(51) characterised in that

(52) the core layer 42, 43, 44 has a thickness h2 of at least 1 mm, in particular at least 1.5 mm, in particular at least 2 mm.

Embodiment 1.9

(53) Freight floor according to any of the preceding embodiments,

(54) characterised in that

(55) the core layer 42, 43, 44 comprises a solid core

Embodiment 1.10

(56) Freight floor according to any of the preceding embodiments,

(57) characterised in that

(58) the wearing layer 23 has a thickness of 0.1 mm to 1 mm, in particular 0.2 mm to 0.6 mm, in particular 0.25 mm to 0.5 mm.

Embodiment 2.1

(59) Freight container, comprising a freight floor according to any of the preceding embodiments and side walls 12a-12d arranged on the freight floor 20.

Embodiment 2.2

(60) Freight container according to embodiment 2.1,

(61) characterised in that

(62) the freight floor 20 at least in portions comprises a peripheral edge profile 25, in particular in the form of a bead, for connecting the side walls 12a-12d to the freight floor 20.

Embodiment 2.3

(63) Freight container according to embodiment 2.1 or 2.2,

(64) characterised in that

(65) the side walls 12a-12d at least in portions are made from glass-fibre-reinforced and/or carbon-fibre-reinforced plastic.

Embodiment 3

(66) Use of a multilayer panel comprising:

(67) a core layer 42, 43, 44 of carbon-fibre-reinforced and/or glass-fibre-reinforced plastic, and

(68) a seating layer 21 of a metal alloy, in particular an aluminium alloy, for production of a freight floor 20 in particular according to any of embodiments 1.1 to 1.10.

Embodiment 4

(69) Method for production of a freight floor, in particular a freight floor 20 according to any of embodiments 1.1 to 1.10, comprising the steps:

(70) production of the core layer 42, 43, 44 of carbon-fibre-reinforced and/or glass-fibre-reinforced plastic; production of a seating layer 21 of a metal alloy, in particular an aluminium alloy;

(71) connection of the seating layer 21 with the core layer 42, 43, 44 by material connection and/or by material fit.

LIST OF REFERENCE NUMERALS

(72) 10 Freight container 12a to 12d Side wall 13 Cover plate 14 RFID tag 20 Floor plate 21 Seating layer 23 Wearing layer 25 Floor plate profile 40 Core 41 GFRP layer 42 CFRP layer 43 Foam layer 44 CFRP layer 47 Rubber layer h Freight container height b Freight container width 1 Freight container length h1 Seating layer thickness h2 Core layer thickness h3 Wearing layer thickness