WO2001005668A1

WO2001005668A1 - Air cargo loading unit having fibre-reinforced synthetic plates

Info

Publication number: WO2001005668A1
Application number: PCT/NL2000/000507
Authority: WO
Inventors: Hendricus Gerardus Hilders
Original assignee: Adprotech B.V.
Priority date: 1999-07-19
Filing date: 2000-07-18
Publication date: 2001-01-25
Also published as: NL1012639C1; AU6189500A

Abstract

Air cargo loading unit, comprising: a base element (1); four upright wall panels (2); and a cover element (6); the wall panels (2), being releasably connected to the base element (1), and the cover element (6), in which the base element (1), the wall panels (2) and the cover element (6) comprise fibre-reinforced synthetic plates (9, 22, 25, 30). In particular, at least one of the synthetic plates is reinforced with a plate-like, cohesive fibrous structure which is composed of a plurality of layers, each having a large number of fibres which are substantially parallel to one another, the fibres of one layer in each case crossing the fibres of another layer, while the fibres of one layer are connected to the fibres of another layer at the crossing points with the aid of connecting fibres.

Description

Short title: Air cargo loading unit having fibre-reinforced synthetic plates

The invention relates to an air cargo loading unit according to the preamble of claim 1. Loading units of this nature are intended to supply and transport air cargo in pieces and are used to replace the measure of stacking pieces of cargo on pallets which are then covered with a net. The units are intended for multiple use. An air cargo loading unit of this nature is known from

WO 98/35890, which discloses a box-like assembly which is composed of a base element, four wall panels which are divided in the vertical direction and a cover element. The base element and the cover element are provided with slots in which the edges of the wall panels can be held. The wall panels which are divided in the vertical direction are connected to one another by means of H-section pieces. The unit is to a large extent made from aluminium. The base element, the cover element and the section pieces are all made from aluminium. The wall panels were in the first instance made from cardboard. In practice, cardboard was found to be unable, or scarcely able, to satisfy the requirements imposed. Also, the cardboard had to be pretreated in order to make it suitable for different weather conditions. Consequently, in practice the wall panels are nowadays frequently made from aluminium.

A drawback of this known loading unit is that aluminium corrodes and is susceptible to damage. The unit quickly becomes scratched, dented and even deformed. This makes it more susceptible to fatigue. The units are handled roughly at airports, and consequently they are often so damaged or deformed after one or more cycles of use that they are difficult or even impossible to dismantle and reassemble without deforming in particular the section pieces back into their original form. Without cargo, the embodiment with aluminium wall panels weighs 45 kg, which is relatively heavy in particular for air cargo, where weight is of critical importance with regard to fuel consumption. Although the unit would have to be intended for loads of up to 500 kg, in practice it has been found that loads of over 300 kg lead to substantial deformation of the base element and the wall panels. Finally, aluminium forms a cold bridge, with the result that cargo held in the unit is quickly exposed to the temperature fluctuations, which are sometimes considerable, during transport. The object of the invention is to overcome the above drawbacks and, in particular, to provide a user-friendly air cargo loading unit which combines a light weight with a high strength and is able to withstand rough handling at airports.

According to the invention, this object is achieved by means of an air cargo loading unit according to claim 1. In this case, the unit is formed by an assembly of releasably connected wall panels and base and cover elements which comprise fibre- reinforced synthetic plates . The fibre-reinforced synthetic plates are able to provide the unit with a very low weight of approx. 32.5 kg, representing a very great saving compared to the prior art. This relatively low weight is advantageously combined with a high strength. The unit can be loaded with a good 530 kg without significant deformation, while the unit is not damaged, or is scarcely damaged, by rough handling. Even after they have been used a large number of times, there are no problems observed with assembling and dismantling the units. Consequently, the air cargo loading unit having fibre-reinforced synthetic plates has a long service life, which advantageously reduces the transport costs. The synthetic plates have an insulating action, so that the load is not exposed so quickly to temperature fluctuations, and the unit can, for example, easily be adapted for use as a coolbox.

In a preferred embodiment, the synthetic plates are reinforced with a plate-like, cohesive fibrous structure according to claim 2, and in particular claim 3. Reinforcing fibrous structures of this nature are usually employed where it is necessary to withstand point loads. Surprisingly, tests have shown that these specific fibrous structures are also very well able to withstand the surface loads which occur in the base element, the wall panels and the cover element of the unit according to the invention. The fibrous structure imparts a high fatigue resistance and strength to the synthetic material, while the weight remains low. In addition, the cohesive fibrous structure provides the base element, the wall panels and the cover element with a quasi-isotropic strength characteristic.

In particular, the fibre-reinforced synthetic plates are processed as composite material. With this, in each case two plates form the skins of a sandwich form, the skins delimiting a core layer made from a lightweight material. The core is formed, for example, by a foam or a honeycomb structure of aluminium, paper or synthetic material.

Further preferred embodiments of the invention are defined in the remaining subclaims .

The invention will be explained in more detail with reference to the appended drawing, in which:

Fig. 1 shows a perspective view of a preferred embodiment of the air cargo loading unit according to the invention;

Fig. 2 shows a side view of Fig. 1;

Fig. 3 shows a partial view, in vertical section, through the front part of the loading unit shown in Fig. 1;

Fig. 4 shows a view in cross section of the loading unit returned to a folded-together state;

Fig. 5 shows a perspective view of two low assembled loading units according to the invention positioned on top of one another;

Fig. 6 shows a diagrammatic plan view of a fibrous structure according to the invention, which is composed of four layers of fibres;

Fig. 7 shows a side view of Fig. 6;

Fig. 8 shows a highly diagrammatic view of a sandwich structure according to the invention; Fig. 9 shows a view corresponding to that shown in Fig.

1 of a variant embodiment;

Fig. 10 shows an enlarged view of the support element from Fig. 9;

Fig. 11 shows a view corresponding to that shown in Fig. 3 through the front part of the loading unit shown in Fig. 9;

Fig. 12 shows a plan view, in cross section, through one of the corner sections from Fig. 9; and Fig. 13 shows how the two corner section parts from Fig. 12 are fitted together, in seven steps.

The air cargo loading unit shown in Figs. 1, 2 and 3 comprises a base element 1 on which there are four wall panels 2 and, as a closure means, a cover element 6. The base element 1 comprises a fibre-reinforced synthetic plate 9 on which there is a section piece 10 into which the wall panels 2 can be fitted. The section piece 10 and the wall panels 2 are provided with complementary click-together connection means 11, by means of which the wall panels 2 can simply be click-fitted onto the base element 1. The click-together connection means are preferably designed in such a manner that they are not accessible from the outside.

The base element 1 comprises four legs 15 which, on the short side of the unit, are connected to one another by a coupling piece 16. On either side of the centre, the coupling piece 16 delimits two trapezium-shaped openings 17. This leg structure advantageously makes it possible to introduce the tines of a fork-lift truck from both the long and short sides and to lift the unit. On the long side, the unit can be displaced with the aid of a trolley. The leg structure is strong and does not give way even after multiple use. The coupling pieces 16 are to a large extent planar and make it possible to transport the unit stably along a conveyor belt. The wall panels 2 comprise four low wall-panel parts 20 and four high wall-panel parts 21. The high wall-panel parts 21 each substantially comprise a fibre-reinforced synthetic plate 22 and a H-section piece 23 which is connected to the bottom edge thereof. The low wall-panel parts 20 each substantially comprise a fibre-reinforced synthetic plate 25. The fibre- reinforced synthetic plates 22 and 25 are each provided with a corner-section piece 27 on one side.

The H-section pieces 23 which are connected to the high synthetic plates 22 and the top edge parts of the low synthetic plates 25 are provided with complementary click-together connection means 28, by means of which the wall panel parts 20 and 21 can easily be clicked together securely. If the high wall-panel parts 21 are placed on top of the low wall-panel parts 20, the entire unit has a height XI of approximately 1500 mm. The short side of the unit has a width X2 of approximately 1020 mm. The long side has a length X3 of approximately 1220 mm.

The cover element 6 comprises a fibre-reinforced synthetic plate 30 with a section piece 31 which can be placed over the top edge parts of the wall panels 2. The section piece 31 and the wall panels 2 are provided with complementary lock means 35, 36, for example four combination locks which are distributed over the circumference or locks which can be activated using a magnetic card. The lock means 35, 36 ensure that the cover element 6 remains on the wall panels 2 and, at the same time, form protection against theft or damage to the cargo.

The section piece 10 of the base element 1 and the section piece 31 of the cover element 6 both comprise a slot part 40 or 41, respectively, extending in the vertical direction. The slot parts 40, 41 are intended to accommodate the edge parts of the wall panel parts 20, 21. Damping elements 42, for example made from foam, are positioned in the bottom of the slot parts 40, 41 (cf . Fig. 3) . By designing the corner-section pieces 27 to be slightly shorter than the height of the wall- panel parts 20, 21, it is advantageously possible for the fibre- reinforced synthetic plates 22, 25 of the wall-panel parts 20, 21 to be pressed slightly into the damping elements 42 under a vertical load, without imposing a load on the corner-section pieces 27.

Fig. 4 shows the folded-together state of the unit. In this case, the cover element 6 is positioned directly on top of the base element 1. The space between the two elements 1, 6 is sufficiently great to accommodate the various wall-panel parts 20, 21. Advantageously, the base element 1 is also provided with complementary lock means 36, so that the various components of the unit are held securely together in the folded-together state. In particular, seven folded-together loading units can be stacked on top of one another and, in this state, take up the same volume as one completely erected loading unit.

If desired, the unit can be assembled in such a way that only the low wall-panel parts 20 are used. This lowered design is shown in Fig. 5. Advantageously, complementary lock means 36 are also provided on the low wall-panel parts 20, which in turn ensure that the cover element 6 remains in place on the wall- panel parts 20 without there being any possibility of unauthorized access to the content of the loading unit. The fibre-reinforced synthetic plates 9, 22, 25, 30 of the base element 1, the wall panels 2 and the cover element 6 advantageously make the unit sufficiently strong to be able to transport a good 500 kg of cargo without the wall panels 2 and the base element 1 bending significantly. The weight of the unit is advantageously low and less than 35 kg. The strength of the fibre-reinforced synthetic plate 9 of the base element 1 is advantageously such that there is no need for any middle legs to be placed beneath the base element 1.

Advantageously, the various section pieces 10, 23, 27, 31 are also advantageously made from an optionally reinforced synthetic material. The legs 15 are advantageously made from a fibre-reinforced synthetic material with a core of foam. Thus virtually the entire air cargo loading unit according to the invention is made from and composed of synthetic material. In particular, the synthetic plates 9, 22, 25, 30 used are reinforced with a plate-like, cohesive fibrous structure as shown in Figs. 6 and 7. The fibres are denoted by 61, 62, 63 and 64, and, by way of example, the fibres 64 are parallel to the longitudinal direction of the synthetic plate which is to be reinforced. The fibres 63 are perpendicular thereto, and the fibres 61 and 62 form angles of +45° and -45°, respectively, with the longitudinal direction. 65 denotes connecting threads which are processed into a stitch which, at the location of the crossing points with the highest density of fibres, encloses the entire stack of fibres (cf . Fig. 7) . During the stitching, the needle does not pass through the fibres, so that they retain their original strength.

As an alternative to the four layers of fibres shown, it is also possible to use different numbers of layers. It is also possible for a plurality of partial fibrous structure assemblies comprising four fibres to be joined together.

The cohesive fibrous structure obtained in this way is embedded in a thermoplastic or thermosetting synthetic plate. The fibrous structure provides the plastic with a substantially isotropic strength characteristic in the plane of the synthetic plate. In addition, the fibrous structure provides a very high strength in a direction perpendicular to the plane of the synthetic plate. The fibre-reinforced synthetic plates are very able to withstand point and impact loads, in particular during rough treatment when an aircraft is being loaded and unloaded.

It will be clear that numerous kinds of fibres can be used, such as ara id fibres. Good results for the loading unit are obtained with glass fibres, carbon fibres and polyester fibres. However, the invention is not limited to the use of the abovementioned fibres.

Advantageously, the base element 1, the wall panels 2 and the cover element 6 are designed with a sandwich structure (cf. Fig. 8), the two skins 81 being formed by fibre-reinforced synthetic plates which together delimit a core layer 82 of a lightweight material. The core 82 may be in numerous different forms, such as a foam structure or a honeycomb structure of paper, aluminium or synthetic material. The sandwich structure may have a thickness of approximately 9 mm and has proven particularly suitable for forming the surfaces of the base element, the wall panels and the cover element of the unit according to the invention.

For the fibre-reinforced synthetic plate of the base element, a carbon fibre is used in particular, while for the plates of the wall panels and the cover element a glass fibre is used in particular.

Fig. 9 shows a variant of the loading unit 90, which is distinguished in particular by the design of the support means 91. The support means 91 comprise a profiled support strip 92 which forms three legs 93 which project downwards. The legs 93 are connected to one another on the underside by a flat support strip 94. The spaces 95 between the legs 93 are suitable for receiving the tines of the fork-lift truck. The flat support strip 94 is suitable for transport along a conveyor belt. The outermost parts of the support means 91 are provided with guide pins 96 which project downwards. The guide pins 96 are intended to lie inside the profiled edge of a cover element of another loading unit. This makes the operation of stacking units on top of one another easier and more reliable. According to the invention, the loading unit 90 is composed of a base element 100, wall panels 101, 102 and a cover element 103, which all comprise fibre-reinforced synthetic plates (cf. Fig. 11) . The wall panels 101, 102 are connected to one another by means of a H-section piece 105 and are locked with respect to one another by means of a locking hook 106 which can be turned from the outside by means of a key. The locking hook 106 is connected to the top wall panel 102 and engages behind a pin 107 which is connected to the bottom wall panel 101.

Advantageously, at least two of the corner sections 110 are of two-part design, each of the corner-section parts being connected to an associated wall panel and being provided with a complementary connecting part. Fig. 12 shows a preferred embodiment having corner-section pieces 112, 113 which are provided with hook edges 114, 115 which engage behind one another. The corner-section pieces 112, 113 can be quickly and easily connected to one another by means of a sliding and rotational movement, as illustrated in steps in Fig. 13. They are easy to release in the reverse order.

A combination of click-together means, which are only accessible from the inside, between the top and bottom side walls and the base element, on the one hand, and hooked edges on the corner-section pieces, on the other hand, enable very simple and rapid assembly and dismantling. A cover element which is provided with lock means can then reliably close off the entire unit.

The cover element is preferably provided with a programmable electronic unit which allows paper-free transport and may comprise functions such as packing list, weight, opening code, destination, position-detection signal and an alarm. Furthermore, a bar code may be applied to the unit as a manual back-up.

Thus, the invention provides a loading unit for air cargo which is inexpensive to produce and has an optimum combination of a light weight, a high strength and a long service life. The various components are preferably made from fire-resistant material which also causes little smoke formation. Thus, the units advantageously form fire barriers in an aircraft and, in the event of small explosions, they can absorb some of the pressure waves. By regarding the units not as packaging material, it is possible to omit the standard cargo nets. The units can easily be standardized and are not only advantageous in air cargo but also are eminently suitable for transport from door to door.

Claims

1. Air cargo loading unit, comprising: a base element (1) ; - four upright wall panels (2); and a cover element (6); the wall panels (2) being releasably connected to the base element (1) and the cover element (6), characterized in that the base element (1), the wall panels (2) and the cover element (6) comprise fibre-reinforced synthetic plates (9, 22, 25, 30) .

2. Air cargo loading unit according to claim 1, in which at least one of the synthetic plates (9, 22, 25, 30) is reinforced with a plate-like, cohesive fibrous structure which is composed of a plurality of layers, each having a large number of fibres (61-64) which are substantially parallel to one another, the fibres (61, 62, 63 or 64) of one layer in each case crossing the fibres (61, 62, 63 or 64) of another layer, while the fibres (61, 62, 63 or 64) of one layer are connected to the fibres of another layer at the crossing points with the aid of connecting fibres (65) .

3. Air cargo loading unit according to claim 2, in which the cohesive fibrous structure comprises four layers of fibres (61-64) and the direction of the fibres (61) of the first layer and the direction of the fibres (62, 63, 64) of the other three layers form angles of 45°, 90° and 135°, respectively, with one another.

4. Air cargo loading unit according to one of the preceding claims, in which the base element (1) , the wall panels (2) and/or the cover element (6) comprise plate structures in sandwich form, with skins (81) of fibre-reinforced synthetic plates which are connected to a core layer (82) made from a lightweight material.

5. Air cargo loading unit according to one of claims 1-4, in which the fibres used are selected from glass fibre.