FIELD OF THE INVENTION

The present invention relates in general to a catering trolley or serving trolley for use in airplanes. BACKGROUND OF THE INVENTION

Such catering trolleys are generally known; an example of such trolley is disclosed in WO-2009/008707. They comprise a cabinet-shaped body, at least one door, an upper panel, wheels, etc. The trolleys are used for presenting for instance meals and drinks, or other articles, to airplane passengers, the trolleys riding through the aisle of the airplane, pushed or pulled by the serving cabin personnel.

As far as dimensions are concerned, there is a high degree of standardization. The outside dimensions are

restricted by the fact that they must fit in an aisle and in a storage cabinet. The inside dimensions are set by the fact that they must be able to accommodate standard trays and drawers. Basically, there are two major variations: there are half -size trolleys and full-size trolleys. A half -size trolley has a depth in the order of 60 cm for accommodating one tray or drawer per level. Such trolley has a front side with a door and a back side with a fixed panel. A full size trolley is twice as deep so that it can, at each level, accommodate two trays or drawers behind each other. Such trolley has two doors at the opposite ends.

The system for accommodating trays and drawers can be indicated as a sliding rail system. The side walls of the trolley body are internally provided with horizontal and longitudinal projections, which will be indicated as rails, and which may be contiguous but sometimes are interrupted. The side edges of the trays or the side walls of the drawers, respectively, rest on opposite rails and the tray or drawers can slide inwards or outwards. This system works satisfactory. The trays/drawers basically exert a vertical force on the supporting rails only, this vertical force being determined by the weight of the contents of the trays/drawers . However, there may be circumstances where these vertical forces are increased (shock) . This may happen during flight, when

turbulence occurs, or on the ground when the trolley rides over uneven surface, for instance. Due to deformations, the vertical forces will obtain a horizontal component, and there will be a tendency of the trolley walls to bulge outwards slightly. Under extreme conditions, it may happen that one or more trays/drawers slip from their supporting rails and drop down, on top of their lower neighbor. This is annoying, because drawers may get stuck between the trolley walls.

The above-described tendency is larger in the case of full-size trolleys compared to half -size trolleys. To date, the tendency is either accepted or reduced by one of the following three methods:

- the trolley walls may be strengthened, but this involves increased weight and costs;

- a horizontal fixed plate is fixed between the walls, also increasing the weight and further limiting the number of vertical locations where a drawer may be positioned;

- a vertical separation wall is fixed half-way in the trolley, also increasing the weight and effectively separating a full- size trolley into two half-size trolleys because it is no longer possible to slide a tray/drawer through to the other side of the trolley.

Further, a general disadvantage of the above methods is that the strengthening and/or separation walls are "forever", i.e. the user does not have a choice to apply it or not.

SUMMARY OF THE INVENTION

A general objective of the present invention is to overcome or at least reduce the above problems and

disadvantages.

According to an important aspect of the present

invention, a flexible longitudinal connection element is attached to the opposing trolley walls, in a detachable manner . BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of the present invention will be further explained by the following description with reference to the drawings, in which same reference numerals indicate same or similar parts, and in which:

figure 1A shows a schematical cross-sectional top view of a trolley;

figure IB shows a schematical cross-sectional side view of the trolley of figure 1A;

figure 2 illustrates a detail of a first embodiment of the attachment of a connection element to a trolley wall;

figure 3 illustrates a detail of a second embodiment of the attachment of a connection element to a trolley wall;

figure 4 is a perspective view of an embodiment of a

connection element;

figure 5 is a perspective view of another embodiment of a connection element.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1A shows a schematical cross-sectional top view of a full-size trolley 1, having opposing side walls 11 and 12 and two opposing front sides (in view of the symmetry there is no distinction between front and rear) 13 and 15 with

respective doors 14 and 16 giving access to the interior 17.

The horizontal direction parallel to the side walls 11, 12 will be indicated as the longitudinal direction, and the dimension of the trolley in this direction will be indicated as the length.

The inner surfaces of the side walls 11, 12 are provided with a support structure for supporting trays or drawers, the support structure typically having the shape of horizontal rails, but this is not shown for sake of simplicity. The figure does show two drawers Dl, D2 arranged in the trolley. The drawers Dl and D2 have a standard length, and the trolley being a full-size trolley means that its internal length is larger than two times the length of a drawer so that two drawers can be arranged at the same level behind each other, as shown. Double-pointed arrows indicate the sliding direction of the drawers. Typically, one such drawer Dl will be accessed via one door 14 while the other drawer D2 will be accessed via the opposite door 16.

A dotted line 18 indicates a vertical midplane,

subdividing the trolley 1 in two sections 2, 3, which

basically is a plane of symmetry: in principle, the trolley 1 could be mirror-symmetric with respect to this midplane 18, but preferably the doors always have the hinges at the same side as seen from the user, as shown. As mentioned, the length of the interior 17 is larger than two times the length of a drawer Dl, D2, so the drawers Dl, D2 can be arranged with longitudinal play: their precise longitudinal positioning is not critical. The difference between the length of the

interior 17 and two times the length of a drawer Dl, D2 will be indicated as longitudinal oversize LO. When the drawers are positioned at an extreme position, touching the respective door when closed, the longitudinal distance between these drawers corresponds to the longitudinal oversize LO.

Figure IB shows a schematical cross-sectional side view of the trolley 1, illustrating that drawers D can be arranged at several levels.

As already mentioned, a potential problem resides in the possibility that the side walls 11, 12 might bulge outwards, increasing the interior width so that at least one drawer is no longer adequately supported and falls on its lower

neighbor. This problem is overcome in trolleys having a separation wall coinciding with the midplane 18, the

separation wall being fixed to the upper, lower, and side walls of the trolley, but, apart from increased weight, this involves the drawback that it is not possible to internally shift a drawer from one trolley section to the other. The trolley of the present invention does not have such separation wall, so that the interior 17 is an undivided, integral space from door to door.

The present inventors have found that it is possible to greatly reduce the bulging possibility by surprisingly simple measures: a point-to-point connection element between the two opposing side walls 11, 12 prevents the side walls, at least at these points, to move away from each other. This connection element is shown in the figures 1A and IB and is generally indicated by reference numeral 100.

The connection element 100 can be implemented in several ways. In any case, the connection element 100 should have an elongate shape. In the context of the present invention, the phrase "elongate shape" for the connection element 100 is used to indicate that the connection element 100 has a length (positioned in the width direction of the trolley) much larger than width (positioned in the longitudinal direction of the trolley) and height.

In any case, the width of the connection element 100 should be less than the longitudinal oversize LO, so that it is still possible to fit two drawers behind each other.

Obviously, the connection element 100 prevents drawers from being shifted from one trolley section to the other, but in order to have this disadvantage be as small as possible, i.e. to affect only one level of drawers, the height should be less than the height of the smallest drawer, and the positioning in the trolley should correspond to a central drawer level.

In one possible embodiment, the connection element 100 is implemented as a rigid bar, having its ends fixed to the respective side walls by means of screws. However, this is not the preferred embodiment.

First, it is preferred that the connection element 100 is flexible. When an external blow is exerted on a trolley side wall, so that such side wall bulges inwards, the connection element 100 may, when rigid, be deformed in a plastic manner, i.e. it may buckle, with the result that when the side walls want to assume their original shape again, this would be prevented by the damaged connection element. The connection element 100 is not intended to prevent the walls from

deforming inwards; when it is flexible, it will simply go limp. The material of the connection element 100 is not essential. For instance, the connection element 100 may be made of metal or plastic. The cross-sectional contour is not critical: it may be circular, square, or even rectangular so that the connection element 100 can be indicated as a strip. In one specific embodiment, the connection element 100 may- comprise a cable comprising a plurality of twisted fibres. As far as size is concerned, cross-sectional dimensions in the order of a few millimeters (1-10) will typically be

sufficient.

Second, it is preferred that the connection element 100 is attached to the respective walls in a releasable manner. Here, the phrase "releasable" is used as opposite to

"permanent", meaning that the connection element can only be disconnected by breaking it, after which it can not be

re-used. When attached releasably, it is possible for an airplane company to decide whether or not they wish to

actually use the connection element even on a flight-by- flight basis. Further, cleaning of the trolley interior is easier when the connection element is removed.

Figure 2 schematically illustrates a possible

implementation of the attachment in greater detail. In this embodiment, the connection element 100 comprises a flexible main body 101, for instance a thin cable of metal or plastic fibres, at the end of which a pin 102 is attached. For

instance, the pin 102 may be hollow and it may be clamped on the main body 101. At its free extremity facing away from the main body 101, the pin 102 has a threaded section 103. A mushroom-shaped connector 110 has a hollow stem 111, provided with inner threading mating with the threading of section 103. The hollow stem 111 extend from the outside through a hole in a side wall 12. The connector 110 has a hood 112 abutting the outer surface 12' of side wall 12. It will be clear that the connection element 100 can be easily screwed loose.

However, a screwing connection may necessitate the use of a tool such as a screwdriver. Figure 3 is a drawing comparable to figure 2, illustrating an implementation where attaching and detaching is even easier. From the inner surface 12", a chamber 212 is made in the side wall 12. In the chamber 212, a plug 200 is fixed, for instance by gluing. The interior surface of the plug 200 may be flush with the interior surface 12" of the side wall 12, or the plug 200 may have a thin flange 201 abutting the interior surface 12" of the side wall 12, as shown. The plug 200 has a plug chamber 210 facing the interior 17 of the trolley, with a side wall 216 and a bottom 213. The wall 12 may be a hollow wall, and the side wall 216 and bottom 213 completely seal the wall 12, assisted by the overlapping flange 201. At some distance from the bottom 213, the plug 200 has a front wall 214 that only partly covers the chamber 210 such as to leave an entrance opening 215 to the chamber 210. The connection element 100 comprises a flexible body 101, for instance a thin cable of metal or plastic fibres, which at its free end is provided with a transverse section 105. The transverse section is introduced into the plug chamber 210, via the entrance opening 215, and lowered to hook behind the front wall 214. It should be clear that the connection element 100 can easily be detached by lifting its free end.

Figure 4 is a perspective view of an embodiment of the connection element 100 and plug 200 of figure 3. It shows that the main body 101 may have a circular cross section, and that the transverse section 105 may have a disc-shaped

configuration. It further shows that the front wall 214 may have a U-shaped recess 217 in its upper edge 216, having a size for accommodating the main body 101. At its upper end, the U-shaped recess 217 may be slightly smaller than the diameter of the main body 101: this provides a snap- fitting for the main body 101, preventing it from accidentally coming loose .

Figure 5 is a perspective view, comparable to figure 4, of another embodiment of the connection element 100 and plug 200 of figure 3. It shows that the main body 101 may have a rectangular cross section, with the longest dimension being vertical, and that the transverse section 105 may have a rectangular configuration. It further shows that the front wall 214 may be strengthened by ribs 221. At is lower side, the transverse section 105 may be provided with hooks 106, which snap behind a rib, as shown, or which, in an alternative implementation, might snap behind the front wall 214 or into an opening in the front wall 214. The trolley 1 will have only one connection element 100; more is possible, but is not necessary. Nevertheless, it is possible that the side walls 11, 12 of the trolley are provided with multiple attachments points (such as plugs 200) at different heights, so that the user may decide to which height to mount the connection element 100, for instance in relation to different sizes of drawers.

It should be clear to a person skilled in the art that the present invention is not limited to the exemplary

embodiments discussed above, but that several variations and modifications are possible within the protective scope of the invention as defined in the appending claims. Any reference signs in the claims should not be construed as limiting the scope.