The essential features of any packaging are strength, limited bulk and moderate cost.

It is well known that provision of adequate packaging presents difficulties in some fields, such as in that of electric household appliances some of which are bulky and heavy but also fragile.

The most widely used material for this purpose is corrugated cardboard, interleaved and sealed outside by a glued on cover.

For greater protection, the corrugated cardboard can be bent over, even several times, to form a complex structure made rigid by glueing.

Another material used with increasing frequency is foam plastic in its several forms of polythene, polystyrene, PVC and polypropylene.

These materials readily adapt to the shape and size of the object to be packaged which is thereby held firm and well protected.

Cost is the main problem encountered in packaging as in most cases it is considered disposable and cannot be reused. Cost of packaging is therefore an important factor in the total cost of the goods to be carried.

It also frequently happens that packaging imposes limitations on the shape and structure of the goods themselves prepared for transport.

On the other hand it is almost impossible to reuse packing material partly because it is inevitably spoilt during removal from the goods and partly because of the difficulty of recovering some of it for further use.

The above invention eliminates or greatly reduces these problems as will now be explained.

Subject of the invention is a process for making"returnable"packing comprising: -two concave structures of thin, rigid, strong material, with two internal trays of thick plastic foam, whose internal shape and dimensions corre- spond to those of the upper and lower ends of the object to be carried; -means for securely fixing said concave structures to the object; -means to protect the edges of the object between the two structures; -means for stable association of the two empty concave structures, when the object has been unpacked, by matching their internal sides, so that they can be returned to the despatching firm for further use.

In one type of execution the concave structures are parallelepipeds.

The concave structures are advantageously of plastic material.

The means for ensuring stability during transport of the two concave structures applied to the object consist of a covering of heat-shrinkable plastic film applied to the packed object and tightened by passing the object through an oven to heat-shrink said covering.

Alternatively said means consist of a film of stretchable plastic material applied to the object by a machine or by hand and tightened.

The means for ensuring stable association of the two empty concave structures put together for re-use, are lateral clamping devices fitted onto said concave structures.

Said clamps consist of elastic tabs, applied to the two sides of one concave structure, one end of the tab, U-shaped with converging sides, projecting from the edges of said concave structure.

Said tab end is so sized that it can be pressed into fissures created on the raised edge of the second concave structure.

Automatic connection between the edges of each tab and the internal edges of the fissures is determined by cuts in said edges of the tab close

to the bottom of the"U".

The two concave structures can thus be separated by datching the cuts from the ends of said fissures, pressing together the two legs of the"U" of the tabs that project from the fissures in the edge of the second concave structure after passing beyond its raised edge.

The clamps, used for putting the two'returnable'concave structures together, are applied to one concave structure by means of pins with elastic studs that can be pressed into holes in grooves made in the sides of the concave structure to facilitate replacement if broken.

The edges of the object to be packed are protected by oblong corner pieces of foam plastic, said pieces having at their two ends means for fastening them to the inside corners of the two concave structures.

The means at the ends of the corner pieces are pin-like projections while those to take them in the corners of the concave structures are cavities of about the same dimensions as the pins, cut into the foam plastic.

The corner pieces are of considerable length and are made in two bodies that can be fastened together for structural continuity by means created at the end of one piece consisting of a triangular expansion on one side and a hook to correspond on its second side, and by means created at one end of the second body and consisting of a cavity of substantially the same shape as that of said triangular expansion at one side and of a counter-hook on the second side.

It follows that by fitting the triangular expansion and hook at the end of the first body into the triangular cavity and counter-hook respectively at the end of the second body, a sufficiently stable association can be formed between the two bodies of one corner piece.

This association is further strengthened by the traction exerted when the covering of plastic film is heat-shrunk onto the object.

Dimensions of the two bodies of the corner pieces are such that they can be placed inside the concave structures when these are put together to be returned to the despatching firm for reuse.

Centrally on the outside of one side of each concave structure, a sub- stantially rectangular recess is cut from the base of the concave structure

up to a short distance from is edge so that when the two concave structures are closed together for returning, the tops of the opposing recesses together form a sort of handle that facilitates transport Alternatively the means for stable association during transport of the two concave structures applied to the object, are straps and the like, one or more of which are passed round the two concave structures.

The straps can be placed parallel to each other or can be crossed one over another.

The straps are tightened by automatically locking buckles and the like that will not come apart spontaneously.

The straps are separate from the concave structures and are kept in place by traction during packaging so that when the packing is removed, they are immediately detachable from the concave structure and can be laid between the two parts when said two parts of the concave structure are put togetherand form a'suitcase'for return and reuse.

The invention offers evident advantages.

The process described makes possible almost complete reuse of the packaging material for any object, even if heavy fragile and bulky, such as household electric applicances for example Packaging need therefore no longer represent a considerable part of the cost of the object, but such packaging can be improved and strengthened so that the protection it affords may be made even more efficient than it is at present.

The fact that, for purposes of return, the packaging can be put together like a'suitcase'with the added convenience of a handle, greatly facili- tates its return to the despatching firm for reuse.

Bearing in mind that there is an almost universal need for packaging, the above invention not only offers advantages for the individual firms that use it but is also in line with present tendencies to avoid waste of materials and lessen pollution in so doing.

Characteristics and purposes of the invention will be made still clearer by the following example of its execution illustrated by diagrammatically drawn figures.

Fig. 1 Returnable packaging subject of the invention of the type suitable for a washing machine, exploded view, in perspective.

Fig. 2 The packaging applied to the washing machine, perspective.

Fig. 3 The packed up washing machine being moved through an oven to heat-shrink the protective plastic film covering, perspective.

Fig. 4 The two concave structures, main components of the packaging subject of the invention, in the process of being put together for return and reuse, perspective.

Fig. 5 The packaging when ready for return, perspective.

Fig. 6 Detail of the means for putting together the concave structures, main components of the invented packaging, for return, cross section.

The packaging 10 comprises the substantially equal concave structures 100 and 101, in the shape of a regular quadrangle.

The concave structure 100 of plastic material comprises the base 12 and sides 13.

Centrally in one side, here called the front side, is a substantially square recess 14 cut close to the edge of the side to form half a handle 18.

Right across the sides, here called lateral, are pairs of recesses 15, in each of which is a pair of holes 16.

These lateral recesses are used for application of the clamps 90 each clamp consisting of a moderately elastic tab 91 of plastic, on one face of which is a pair of elastic studs 92 that can be pressed into the above pair of holes 16.

The clamps remain stable but can be replaced if they become broken.

The free end of a tab is U-shaped 93, and opposing notches 94 are cut close to the U, one in each side.

The clamps are used to close together the two opposing concave structures 100 and 101, as will be explained below.

A tray 20 of foam plastic material is placed inside the described structure 100, the outer dimensions of said tray substantially corresponding to the internal dimensions of the concave structure.

In the front face of said tray 20 is a cleft 23 its position being the same as that of the recess 14 made in the front side of the base 100 to form the

half-handle 18.

The concave structure 101 of plastic material comprises the base 32 and sides 33 with edge 37.

Centrally in one side, here called the front side, is a substantially square recess 34 cut close to the edge of said side to form a half-handle 38.

In the sides, here called lateral, there are a pair of recesses 35 each one extending fully up the side, to the position of a fissure 36 in the raised edge 37.

The tray 40 of foam plastic material is placed inside the concave structure described, said tray having a base 42 and sides 41 whose external dimensions substantially correspond to the internal dimensions of said structure.

At the position of the recess 34, made to form a half-handle 38, there is a cleft 43 in the side 41 of the tray 40 to allow room for said recess 34 in the front side of the concave structure.

As the example in Figure 2 shows, the two concave structures 100 and 101 can be fitted over the top and under the base of the washing machine 80 as the internal dimensions of said structures are the same as the external dimensions of said top and bottom of the washing machine.

The foam plastic corner pieces are applied to protect the vertical edges of the washing machine.

Figure 1 shows the two pins 54 and 74 placed at the two ends of the corner pieces 50, the size of said pins being such that they can penetrate inside the seats 24 and 44 cut in the edges of the trays 20 and 40.

Said corner pieces are each formed of two oblong bodies 51 and 71 of substantially the same height associatable in the following way.

A triangular projection made at the lower end 58 of the body 51 on one of its sides 53, can penetrate inside the upper cavity 76 on one side 73 of the body 71 and, on the other side 52, the hook 57 can fit into the cut 78 made in the second side 72 of the body 71 as may be seen where the corner pieces 50 are shown joined together.

Association of the various parts described 100,101 and 50 for transport is assured by heat-shrinking over it a wrapping or bag of plastic material.

Figure 2 shows in 81 the packed up washing machine 82.

Figure 3 shows in 83 the packed up washing machine 82 covered with the heat-shrinkable film 85.

Said machine is then passed through the oven 110 carried by a trans- porter comprising continuous belts 111 pulled by pulleys 112 and 113 fitted onto shafts 114 and 115, and also the doors 116 and 117.

On leaving the oven the washing machine appears, at 83, firmly packed by the bodies 100,101 and 50 held together by the sheets of shrunk-on plastic material 85.

On arrival at its destination the packaging can be easily and completely removed without damaging it in any way, simply by pulling off the above shrunk-on wrapping of plastic material The bodies 51 and 71 of the corner pieces 50 are placed side by side in the trays 20 and 40 after which the concave structure 101 can be placed over the second concave structure 100 and firmly fixed by the clamps 90.

Said clamps are closed by fitting their tips 92 inside the fissures 36 made in the edge 37 of the concave structure 101. The ends of said fissures become inserted in the notches 94 made in the elastic tips 92 of the clamps, thus firmly closing the'suitcase'120 formed of the two concave structures 100 and 101 with handle 121.

The packaging, by then in'suitcase'form, can therefore be conveniently returned to the firm that delivered the washing machine for further use with undoubted advantages of cost and efficiency.