The present invention relates to a method according to the preamble of Claim 1.

French Patent Specification 2,3^3.6 describes a method for manufacturing cylindrical receptacles at two locations. At the first location, a sleeve-shaped, and, more particularly, a conical wall part, is formed, provided with a base. These conical semifinished articles are stacked on one another and can be transported in an efficient manner. After all, transportation of cylindrical receptacles having the same dimensions and which cannot be nested in one another in fact essentially amounts to transporting "air", as a result of which the transport costs become especially high.

In a second location, according to French Patent Specification 2,3^3.655 a further treatment is carried out, consisting of outwardly pressing at least the part of smallest diameter of the conical sleeve, which is located near the base. In this case, it is necessary to make special arrangements in the region of the base. It is proposed to deform the base part only slightly, and to provide the part of the conical sleeve near the base with a bevelled shape in the final embodiment, which consequently, in fact, forms part of the base. The disadvantage of this method is that the receptacle which thus results is different from customary receptacles which are generally accepted. Consequently, such receptacles have still not made an impact on the market. Moreover, during the deformation of the conical sleeve to a cylindrical sleeve, the attachment between base and sleeve-shaped wall part is subjected to considerable stresses resulting, in practice, in problems with the seal between these two parts which becomes evident only during subsequent use.

The object of the present invention is to overcome these disadvantages. This object is achieved in the case of the method described above by means of the characterizing part of Claim 1. By means of, according to the invention, fitting the base part after transportation

and after transformation to the final size of the sleeve-shaped part, it is possible to produce a receptacle with a conventional external appearance. This is especially so in the region near the base. Moreover, the fold or weld seam between the base part and the sleeve-shaped part is not subjected to the deformation stresses, so that unfavourable transportation and storage conditions have no effect on the final product. Finally, according to the invention, the sleeve-shaped wall part is subjected to a surface treatment before transportation.

In this case, it is possible, on the one hand, to coat the blank from which the sleeve-shaped wall part is manufactured at least on one side before manufacturing the sleeve-shaped wall part from this blank. Such a stage of coating before shaping into a sleeve-shaped wall part is especially advisable if the coating takes place in an even larger-scale manner than the shaping of the sleeve-shaped wall part. In particular, major investment is required in apparatuses for carrying out lacquering and other coating operations, and the like. These relate to both the efficiency of production of the coating material and compliance with environmental/engineering requirements. Such lacquer trains could therefore be used for coating blanks for both straight cylinder-shaped receptacles, lids and bases, and blanks for forming the sleeve-shaped wall parts described above. In this arrangement, it is possible to transport the blanks which have been coated in this manner over a considerable distance to another apparatus where they are shaped into sleeve-shaped parts. Obviously, if welding is used in order to produce a sealed sleeve-shaped form, it is desirable not to provide the free end of the blank with a coating layer if this will impede welding. A layer may be provided locally at a later stage. Such a coating layer may comprise powder coating.

According to an advantageous embodiment of the invention, the sleeve-shaped wall part is subjected to an anti-rust treatment before transportation. This is particularly important in the case of receptacles in which the wall part remains at least partially uncoated. This is the case for a major proportion of all receptacles. If the receptacle is totally coated, such an anti-rust treatment is less necessary. In this manner, it is possible to store the sleeve-shaped wall parts without the characteristics of the sleeve-shaped wall part deteriorating immediately.

After the sleeve-shaped wall part has been deformed into a cylinder with the related final shape, the lid can be fitted. Obviously, instead of fitting a lid, it is possible to create a facility with which

it is possible, with the aid of, for example, a clamping ring, to incorporate a removable lid.

The attachment between the base part and the sleeve-shaped wall part may be achieved using any methods which are known in the prior art. The sleeve-shaped wall part may have either a conical form or a cylindrical form. If the sleeve-shaped wall part has a cylindrical form, it is preferable to place a number of sleeve-shaped wall parts with different diameters inside one another during transportation. These are subsequently subjected to varying degrees of deformation at the second location in order to arrive at final wall parts which are all essentially of the same size. In this case, it is, on the one hand, possible to manufacture different cylindrical wall parts by bending blanks of different length and joining them up, and, on the other hand, it is possible to start with the same standard undersized component and to subject this to different deformations at the first location in such a manner that the resulting differently shaped sleeve-shaped parts can be placed inside one another during transportation. In this case, it is preferable for the increase in diameter of the cylindrical parts to be no greater than 10 during the one or more deformation operations. Surprisingly, it was found that, if accurate tolerances are employed, it is possible, within a specific volume, to transport a greater number of sleeve-shaped wall parts designed as nestable cylinders than sleeve- shaped wall parts, as in a second possible embodiment of the invention. In order to be able to stack the conical wall part without wall parts placed inside one another becoming fixed in one another and difficult to separate, circumferential protuberances may be provided. These may be present either on the inside or on the outside. If a base part is used with the conical wall part, it is necessary to provide the circumferential protuberance near the free end on the outside. Because no base part is present, it is possible to provide the circumferential protuberance on the inside near the free end with a smaller diameter. This latter case has the advantage that, during subsequent deformation into a cylindrical part, such a circumferential protuberance may disappear. In the case in which an external circumferential protuberance is provided near the free end of largest diameter of the wall part, it may be desirable on the grounds of symmetry to provide a corresponding circumferential protuberance near the other end during subsequent deformation into a cylindrical wall part. It is also possible, during deformation of the conical wall part into a cylindrical wall part, still

to form an internal circumferential protuberance. This is particularly important if there is a requirement to adhere to maximum external dimensions of the receptacle, in which case attempts are made to make the volume of the receptacle as large as possible whilst, in addition, there must be sufficient strength particularly to resist implosion.

According to an advantageous embodiment for manufacturing internal circumferential protuberances, the initial conical wall part with a smooth wall is deformed outwards in such a manner that an internal circumferential protuberance occurs locally. The invention also relates to the semifinished article produced using the method, i.e. the sleeve-shaped wall part. Optimum nestability of conical wall parts may already be achieved if the smallest diameter of the conically shaped wall part is less than 20 and, more particularly, less than 10 smaller than the largest diameter. In order to prevent fixing together during nesting, the conically shaped wall part is preferably provided, near the part of largest diameter, with an external protuberance. It is also possible to provide an internal protuberance near the part of smallest diameter.

The invention also relates to a receptacle manufactured from the sleeve-shaped part described above. In this case, the wall thickness of the receptacle will vary as a result of deformation. Such a variation is relatively small and, preferably, smaller than 5 >

The invention also relates to an apparatus for deforming a conically shaped wall part into a cylindrical wall part, or a cylindrical wall part into a larger (in terms of diameter) cylindrical wall part. This apparatus comprises, according to the invention, a carrier for a wall part, an expansion member and means for moving the expansion member in and out of the wall part. Obviously, after the expansion member in the non-operating state has been moved into the wall part, this expansion member will be moved into a state in which it is moved outwards, so that deformation of the wall part to the desired form is achieved.

The invention will be described in more detail on the basis of an embodiment depicted in the drawing. In the drawing:

Fig. 1 shows the conically shaped wall part according to the invention in cross section;

Fig. 2 shows several semifinished articles manufactured according to Fig. 1, nested in each other;

Fig. 3 shows a further embodiment in cross section of the conically shaped wall part;

Fig. < shows the conically shaped wall parts according to Fig. 3 in the stacked state;

Fig. 5 shows a receptacle manufactured from the conically shaped wall parts according to Fig. 4; Fig. 6 shows a number of sleeve-shaped wall parts constructed as cylinders stacked in one another; and

Fig. 7 shows, diagrammatically, an apparatus for deforming conical wall parts into cylindrical wall parts.

The semifinished article shown in Fig. 1 is indicated overall by 1. It comprises a conical wall part 2. Fig. 1 also shows that the conically shaped wall part is provided with a circumferential rib 6 and has no base.

Fig. 2 shows various conically shaped wall parts of this type nested in one another. Owing to the presence of the circumferential rib 6, fixing together is prevented because the consecutive semifinished articles rest on one another by means of these circumferential ribs. Fig. 2 clearly shows that, by mutual nesting, it is possible to achieve a considerable reduction in volume during transportation.

Fig. 3 shows a further embodiment of the conical wall part. In this case, the conical wall part is indicated overall by 16. In this embodiment, an inwardly-facing circumferential protuberance 17 is provided, which facilitates stacking, as can be seen, in particular, in Fig. 4. Such an embodiment has the advantage that, during subsequent deformation into a cylindrical wall part, circumferential protuberance 17 may disappear during deformation. Consequently, it is no longer possible to see that the cylindrical part has been manufactured from an initial conically shaped wall part.

Fig. 5 shows the receptacle after the conical wall part has been cylindrically deformed, after which the cylindrical part is provided with a base. Such a receptacle is no different from customary receptacles.

Fig. 6 shows a number of sleeve-shaped parts constructed as cylinders placed inside one another. These sleeve-shaped parts are indicated by 3. 4, 5» 3 and 18. The mutual distance between these parts is represented as comparatively excessively large, which is shown by broken lines. In practice, the parts will have a mutual spacing of no more than a few millimetres.

By way of example, in the case of a stack consisting of 5 cylindrical sleeve-shaped parts, an external diameter of 571-5 mm may be

mentioned, whilst the internal diameter is 539 mm. In this case, the outermost sleeve-shaped part obviously does not need to be deformed any further, whilst the deformation of the innermost sleeve-shaped part is limited. In the above example, the distance between the receptacles is 1.2 mm, for a wall thickness of 1 mm. If a distance of 0.6 mm between adjacent sleeve-shaped parts, each having a thickness of 1 mm, were chosen, it would be possible, within the range given above, to stack ten sleeves with the deformation of the smallest sleeve exceeding the final dimension by no more than 6% . From a production technique viewpoint, it is perfectly possible to operate with such close tolerances. It will be understood that, in this manner, a considerably larger number of sleeve- shaped wall parts can be transferred per unit volume than in the case of conically shaped sleeve-shaped wall parts nesting in one another. After all, with conical nesting, there is always the risk of mutual fixing and, in order to prevent this, it is necessary to provide circumferential ribs, which in turn gives rise to a less efficient use of space. Use of the cylindrical sleeve-shaped wall parts stacked in one another has the further advantage that each of the wall parts rests on the transportation apparatus, such as a pallet. This contrasts with the mutual nesting of conical parts in which the bottom sleeve-shaped conical wall part has to support the other parts.

Fig. 7 shows, diagrammatically, by 20, an apparatus for expanding conically shaped wall parts 2. This comprises a carrier 21 on which a semifinished article 1 may be placed. This carrier 21 can be moved up and down with the aid of a jack 23- In this manner, a conically shaped wall part 1 or cylindrical wall part 4, 5. 13 or 18 can be moved in an expansion mandrel. After insertion therein, the expansion mandrel will be moved outwards, in a manner which is not shown, as a result of which the cylindrical form is achieved, and, after fitting a base and lid, the receptacle shown in Fig. 5 is achieved. At the same time, prior or subsequent thereto, the various circumferential ribs can be formed. Before transportation of the semifinished articles 1, these are subjected to an anti-rust treatment. This anti-rust means may subsequently be removed. Obviously, any other expansion member which is known in the prior art may be used instead of an expansion mandrel.

In an illustrative embodiment of the invention, it was found that, for a standard receptacle with a height of 88 cm, conical wall parts may be used, approximately 12 of which in a stack give a height of 230 cm.

Through the use of cylindrical sleeve-shaped wall parts, up to twenty cylinders could be placed within a height of 200 cm. This clearly shows the enormous saving which can be achieved. In the case of the standard receptacle with a height of 88 cm described above, it was found that a conical wall part is satisfactory, with a maximum external diameter of δ5 nun and a smallest diameter of ^0 mm.

Although the invention has been described above on the basis of a preferred embodiment, it will be understood that many alternative forms thereof may be provided without departing from the scope of the present application. All existing techniques for assembling and treating receptacles may be used in combination with the invention and rights are expressly applied for in respect of such a combination.