The invention relates to stackable boxes which may be coupled to each other by locking means, said locking means being formed by locking parts at the bottom of a box which are capable of cooperating with locking means at the top of a box, wherein a removable cover has locking means at the bottom which are of the same type as the locking means at the bottom of a box.

Stackable boxes are known e.g. from DE Utility Model No. 78 28 640. These known boxes, which may have mutually different heights, may be coupled to each other and be terminated at the top by a cover.

according to the preamble of claim 1, EP 555 533 B1 also discloses stackable boxes according to the preamble of claim 1, which may be coupled together.

According to this patent, all the boxes have a cover which is confined between two boxes when the boxes are clamped together.

Thus, the boxes are clamped together analogously with the boxes in the above-mentioned utility model, but with a cover which is arranged between the boxes.

Accordingly, an object of the invention is to provide stackable boxes with or without a cover, which may be coupled together in order to achieve a more flexible stacking, where boxes and covers may be coupled together in an arbitrary order.

The object of the invention is achieved by stackable boxes of the type defined in the introductory portion of claim 1, which is characterized in that the cover has locking means at the top of the cover which are of the same type as the locking means at the top of a box.

Hereby, boxes and covers may be coupled together in an arbitrary order.

For instance, three boxes without a cover may be coupled together, or two boxes without a cover may be coupled together with a box having a cover, and in an arbitrary order.

It is even possible to stack several covers on top of each other, if the teachings in claim 1 are followed.

A user-friendly way of configuring the boxes and the covers is, as stated in claim 2, that the locking means at the bottom of the boxes and the covers are formed by at least one snap lock, which is adapted to grip an edge at the top of the boxes or the covers.

Expediently, as stated in claim 3, the covers and the boxes have two snap locks and two edges, and, as stated in claim 4, at least one snap lock is biased, which results in an embodiment which makes it easy to couple-together the stackable boxes and covers and to separate them from each other.

When, as stated in claim 5, the cover is provided with a carrier grip which is recessed into the cover, and, as stated in claim 6, the covers and the boxes have a snap lock at the bottom and an edge at the top in their one end portion, while they have hooks or flanges at the bottom in their opposite end portion, which are capable of engaging fixing holes positioned at the top of the cover or the box, it is advantageously ensured that the snap locks of the stackable boxes are not subjected to loads, which may occur if the stackable boxes are very heavy, as the separation of the boxes from each other takes place in that the one snap lock is loosened from its edge on an underlying box or cover, following which the loosened box and the overlying boxes are pushed to the side, and then the carrier grip is used for lifting the boxes away from the underlying boxes.

When the boxes are coupled together, they are moved laterally inwards, whereby the hooks or the flanges extend into the fixing holes, while the snap lock automatically locks the boxes to each other.

Finally, as stated in claim 7, it is possible that the snap locks are arranged in the end portions on the sides of the boxes and the covers.

The invention will now be explained more fully with reference to the drawing, in which

• fig. 1 shows a box with a snap lock and an edge according to the invention,
• fig. 2 shows two boxes with a cover which are coupled together, while
• fig. 3 shows two boxes and two covers in a separated state, seen from the side in section, but with a snap lock modified relative to fig. 2.

It is noted initially that the parts which the covers have in common with the boxes are provided with the same reference numerals as the boxes, but with a suffixed "a".

In fig. 1, the numeral 1 indicates a box which has locking means in the form of a snap lock 2 near its bottom in its one end portion, said snap lock being formed by a plate which may rotate about a shaft.

The snap lock is biased by a spring 3 so that its plate will normally be flush with the vertical wall of the end portion.

At its top, the box has an edge 4 which is adapted to receive a snap lock from another box 1 or a cover 1a, as will be explained below.

Finally, at its opposite end, the box has another snap lock, which, however, need not be biased by a spring, but may be made of a resilient material, cf. also fig. 3.

Further, the snap lock 2 and the edge 4 are configured in the same manner as described in EP 0 799 115.

Fig. 2 shows two boxes 1 with covers 1a which are coupled together.

At their lower side, the boxes 1 have snap locks 2 which are biased by a spring 3.

At their lower side, the covers 1a have snap locks 2a which are biased by a spring 3a.

At the upper side of the covers 1a, which have a recessed carrier grip 8, edges 4a are arranged, which are adapted to grip snap locks 2, 2a from an overlying box, or, although it is not shown, snap locks 2a from an overlying cover.

1 In figure 3, the boxes 1 and the covers 1a have a spring-biased snap lock 2, 2a at their one end, while the snap lock 5, 5a at the opposite ends may be made of a resilient material.

The spring-biased snap locks 2, 2a have engagement faces 6, 6a, while the snap locks of a resilient material have engagement faces 7, 7a.

When the boxes 1 and the covers 1a are assembled, as shown in fig. 3, a cover 1a having a snap lock 5a without a spring is caused to engage an edge 4 on an underlying box 1 with its engagement face 7a by lateral displacement of the cover 1a.Then, the snap lock 2a with the spring 3a will engage the edge 4 on the box, whereby the cover 1a is coupled to the box 1.

The process may be repeated so that a plurality of covers 1 and boxes 1a may be coupled together in an arbitrary order, however, the covers 1a may also be coupled to each other.

However, it is also possible to arrange hooks or flanges at the opposite end portion, which may engage fixing holes, which, however, are not shown in the figures.

Finally, it should be mentioned that, although it is not shown in the figures, it is also possible to couple two or more covers together on top of each other.

As will be appreciated, the invention provides an extremely flexible stack-1 able box system, where boxes 1 and covers 1a may be coupled together and be separated in an arbitrary order, where the stackable box system may serve as a general storage device.