Patent Application
20060237118
The invention generally relates to a can body, to a method and to a device. The invention concerns vessels or cans which include a base on one end face of a jacket-like closed wall, and of which preferably at least one layer of the wall and the base is made of metal.
Vessels may be formed, for example, as aerosol cans or as beverage cans. Further, cans may be made of aluminum as well as of sheet steel. In order to give the vessels a desired appearance and to apply the necessary information, the jacket-like wall is provided with decoration and labeling. The decoration is, for example, directly printed onto the can. If need be, however, the decoration can be printed onto labels or foils that are then applied to the can wall.
One printing cylinder must be used per color with the current printing method. The printing costs correspondingly increase with each color required. In addition to decorative or graphically configured labelings, standardized information, such as perhaps a bar code, information on hazards and the composition of the product, and if need be promotional information, must also be applied to the can wall. Moreover, a bar code with a dark color, preferably black, must be printed on a bright background, preferably white, which strongly impairs the aesthetic effect of the decoration, especially with dark overall surfaces.
Furthermore, usually two additional colors with the corresponding printing costs are needed for the bar code. Only the precise number of cans that are to be brought into commerce with the current bar code or the current advertising information may be manufactured. In the event that the same can is to reach the market at another point in time with another bar code, then additional cans with the old decoration and the new bar code or new advertising information must be manufactured. If need be, a label with the new bar code can be manufactured, which is glued over the old bar code or the old advertising information, which is associated with much expenditure and is not aesthetically satisfactory.
It is likewise aesthetically unsatisfactory that in cans having a curved transition region from the can base to the can wall the decoration cannot be printed on in the transition region after the base is formed, which, when the can is standing on its base is manifest as an unsightly or not printed lower edge.
Due to lower manufacturing costs, today more and more products are being sold in cans made of sheet steel. It has now been found that such sheet steel cans rust on the base, especially when used in wet cells. The cans may stand over long periods of time with their annular support surfaces on a wet surface, or if worst comes to worst, on surfaces that are contaminated with other substances. Moreover, moisture and materials added to this as well as electrical effects can bring about corrosion.
Even with sheet metals that are provided with a thin chromium layer, undesired oxidation has already been observed. The corrosion leads to a contamination of the surface on which the can is standing, and weakens the base of the can. A weakened can base is dangerous in aerosol cans, especially when butane or propane is used as the propellant gas.
In order to be able to withstand the pressure in the interior of the can, aerosol cans have a base that is arched toward the can's interior. This base is constructed via a pressing process and includes an inwardly arched central region and a downwardly projecting annular edge region where the can base transitions into the can jacket. The cans stand on the annular edge region that can be weakened by corrosion along the support line so that the central region of the base could break out. With can materials having a thin chromium layer, the chromium layer along the support line can be damaged or eliminated by rubbing motions on conveyor facilities of the filler so that corrosion protection is absent to some extent in the corrosion-endangered edge region. Cans whose bases are connected to the jacket via a fold have a narrow, annular downward standing rim that can be easily damaged or oxidized. Corrosion and possibly other chemical and electrical effects can lead to undesired discolorations of the surface on which the can stands.
Solutions are known from the publications EP 200 098 A2 and EP 208 564 in which elements of two-part and multiple part cans are joined with laser beams. Here the elements to be joined are arranged butted, overlapping and also running toward one another at right angles. The laser welding seam is formed for example on the end face, penetrating one layer or as a flat-lap weld. The solutions described are not aesthetically attractive and cannot prevent a possible corrosion of the base.
From U.S. Pat. No. 4,455,850 a beverage can is known in which the central inwardly arched region of the base is coated with a dull color. In this manner, sunlight is prevented from being focused by the concave can base, which could cause a fire to be ignited by cans thrown away outdoors. The coating does not extend over the annular transition region so that the corrosion problem is not solved.
Moreover, the paint is sprayed onto the flat sheet metal so that when stamping out the sheet metal disks and deep drawing the cans, care must be taken that the applied round paint spots are struck exactly centrally by the stamping tools, which is associated with an increased manufacturing expenditure. Even if the paint were to extend over the annular transition region, the paint layer would no longer be continuous after deep drawing the can and pressing the base. Also, rubbing the transition region on conveyors of filling assemblies would lead to damage of the paint layer. Without a continuous paint layer, the already mentioned danger of corrosion exists once again.
A beverage can is known from U.S. Pat. No. 5,992,892 in which information is printed on the central inwardly arched region of the base that is covered with a coating that can be rubbed off in the finished can. This solution makes possible an advertising game in which the buyer of a can can determine, after rubbing off the layer, whether he/she has won anything in accordance with the information lying under it. The annular transition region with the supporting ring thus remains without coating, hence the corrosion problem is not solved. Moreover, the rubbed off coating, or the coating that can be worn off, is not suited for continuously coating the support ring. The removability of the coating is crucial for the promotional game.
U.S. Pat. No. 6,073,797 discloses a cover that is engageable in connection with the upper end face with the aperture to a beverage can. In order that the top remains locking on the can, an outwardly projecting annular region must be provided on the can end, via which a corresponding elastic annular region of the cover can be inverted until it locks. Such a top is very expensive to manufacture and install. Moreover it cannot be installed on the can base due to the lack of an outwardly projecting annular region.
A further cover that is installed by screwing only at the opening of a beverage can is known from U.S. Pat. No. 5,711,447. The screw lock of this cover requires outwardly projecting ribs on the beverage can that can interact with inward-standing elements on the cover. The features necessary on the can and on the cover for use of the cover are extremely expensive to manufacture It is also very expensive to screw the cover onto the can. Therefore, the possibility of arranging a promotional article in such a screw lock is associated with an excessive expenditure.
An embodiment of the present invention is based upon the task of finding a simple solution for a can that can advantageously be aesthetically configured without being impaired by a bar code or advertising information. In particular, a possible corrosion on the base is to be prevented.
In one embodiment, it was recognized in accomplishing the objective that corrosion problems and aesthetic problems can both be solved by applying an external covering in the form of a sheet material. The sheet material is fixed in position on an annular connection region of the can body. If the connection is formed along a closed circular line, the membrane-like base covering receives a high level of stability.
The base covering is basically constructed flat in a main region that is surrounded by the annular connection region and preferably includes the printout of a bar code. If the bar code can be applied on a basically even base surface, then the impairment of the possibility of designing the can wall disappears. No printing rollers for the bar code are necessary for printing the decoration on the can wall. Large amounts of can bodies with an attractive standard decoration on the can wall can be manufactured. Possibly changing information, or information that is not identical for all countries, such as the bar code or even the filling date, and/or aesthetically disturbing information are printed on the base covering. These potentially different base coverings can be printed shortly before the filling time of individual product batches, and can be fixed into position on the standard of the can body. In this way, the same can can be used for all countries and filling batches.
Because the base covering can be constructed flat in the region of the bar code, the bar code is more readable than a bar code that is applied to a curved can wall. If the coating of the exterior of the can wall extends up to the outer edging of the base covering in the form of at least a paint layer or a decorative foil, then a metallic edge becoming visible on the lower can edge can be prevented. The base covering may cover an annular downward-projecting stand region of the can body, thus preventing the occurrence of corrosion problems.
The base covering is preferably constructed in the form of a sheet plastic material. It is obvious that sheet material having at least one metal layer, especially ar, aluminum or steel layer, or even with a cardboard layer, can also be used. Here the stability-imparting layer may also be coated with plastic.
The sheet materials that are used should guarantee a robust base covering that will not be damaged on the conveyor apparatuses of filling assemblies and also will remain as constant as possible even when standing on wet supports. The aforementioned sheet materials can all be provided with a sealing coating and consequently can be sealed on the base. When metal foils are used, the heat required for the sealing process can also be introduced inductively. A latching connection or a welded connection can also be used instead of a seal connection for fixing the base covering into position, especially with at least three laser welding points.
It is obvious that the base covering of an embodiment of the invention is not restricted to use in cans. There are also vessels, especially plastic bottles, the bases of which include an annular downward projecting base region and on which consequently a base covering can be fixed. Although there exists no danger of corrosion with plastic vessels, the use of base coverings for the placement of bar codes and advertising information on vessel bases is advantageous.
If a decorative layer in the form of at least one paint layer, but preferably as a decorative foil, is applied on the exterior of the can wall, then the base covering can be constructed such that the decorative layer extends at least to the outer edging of the base covering. Preferably, however, the decorative layer is somewhat overlapped by the base covering. This prevents foils from being able to loosen on the end region of the can body when decorative foils are used.
When decorative foils are used, a can body with a can wall and base can be manufactured economically corresponding to the respective requirements. If need be, a decorative foil can be subsequently applied to the can wall so that imprinting the can body can be dispensed with. If the can wall and base are pressed from a single element, as perhaps with aerosol cans made of aluminum or with cans made from steel sheets, then the necessary intensive cleaning and drying for imprinting can be dispensed with. A peeling of the foil can be ruled out with foils closed in the peripheral direction that are overlapped by the base covering. If the can body is assembled from a jacket and a base, these two parts may be joined to one another via a folded seam, but preferably a welded seam, especially a laser welded seam. A decorative foil is preferably applied after this joining step, wherein preferably a close and in particular firm application of the foil on the can body can be guaranteed by using a shrinkable foil, especially with a sealing layer that faces the can body. If the can jacket and base are joined using a folded connection, then the folded connection may also be made after the decorative foil is applied, whereby then the folded seam would take over holding the foil on the lower end of the can.
The base covering, or if need the decorative foil as well, permits a covering of the connection between the jacket and base so that no high aesthetic standards must be imposed on this connection. When a welded seam or laser connection is used, the annular connection region is preferably formed by an end region of the can jacket projecting over the base, wherein this end region is drawn especially somewhat toward the can axis and forms the annular transition region. With a folded seam, this can be constructed in the region of the can base and if need be can be pressed toward the interior of the can such that a curved jacket end region can be used as an annular connection region. With these described variants, a base covering that is fixed into position on the annular connection region bridges the respective connection seam
In order to produce an aesthetically attractive can body, the transition from the can wall to the base covering is constructed circular segment-like in longitudinal section, whereby it preferably has a curvature radius ranging from 1 to 6 mm, especially basically 3 mm.
Thanks to the base covering it is now possible, for example, to furnish a two- or three-piece aerosol can of sheet steel that has the appearance of a one-piece aluminum can. The possible embodiments in the base area have already been described above. In order to form the valve seat on the upper end face of the can, a compression necking process can be provided in the case of a two-piece can, and the use of an upper end piece with valve seat in the case of a three-piece can.
Obviously the invention includes all solutions resulting from the combination of the features and embodiments described. Varying the features includes, for example, choosing between one-, two- or three-piece cans, with two- and multiple-piece cans, the choice of various modes of connection between the parts, providing or omitting a decorative foil, the choice of a specific base covering and its fastening on the can body as well as the selection of material for the can and the base covering. Even unexpected combinations can lead to advantageous solutions. Thus, for example, a one-piece aluminum can with a base covering that includes magnetizable sheet steel has the advantage that this can can be conveyed via magnetic conveyors while using magnetic forces of adhesion with various axis alignments.
The possibility of clamping a decorative foil firmly on the lower can end with the base covering opens up a many sided use of decorative foils. These foils are imprinted when needed on their exterior, but preferably on the side facing the can body. The printed layer is protected with a transparent foil that is imprinted on the reverse side, or on the side facing the can body, so that no friction-conditioned impairments of the decoration can arise. A transparent foil printed on the reverse side can be provided with a sealing layer after imprinting through the printed layer, which also guarantees a seal connection between the foil and the can body. In order to be able to shrink the foil on the can body a piece of foil is shaped in a first step into a closed foil jacket and joined together on the two side lines allocated to each other, whereby preferably a seal connection is created. This foil jacket has a slightly greater cross section than the can body and can thus be inverted over the can body and shrunk on the latter as well as sealed fast with the application of heat. After applying the decorative foil, the base covering is fixed into position such that it somewhat overlaps the foil end on the base. It is obvious that the base covering can also be constructed annularly so that it holds the end of the foil securely on the can body but does not completely cover the can base.
Applying foils to a can body is known, for example, from EP 1 153 837 A1, wherein however there with each foil segment, the printed layer may not be applied up to the foil edge, respectively a blank foil edge is needed. In accordance with this known solution, a sealing layer arranged between the foil and the printed layer must lie open when constructing the closed foil jacket to generate a sealing seam. Therefore the imprinting and the succeeding cutting of the foil track must be exactly harmonized with each other, which is not attainable with simple expenditure with a thin foil due to its elastic deformability. In this connection the present invention provides a simplification. Because a sealing layer is applied to the printed layer, the printed layer can be constructed continuously. Cutting the pieces of foil need not precisely agree with the printing, and the formation of a sealing seam is always guaranteed.
A sufficiently shrinkable foil can guarantee that the decorative foil lies free from folds on the body after the shrinking process in the drawn-in base region, and if need be also in a drawn-in upper end region. Because weld seams and especially laser connections can be constructed such that the surface of the can body is basically smooth even in the region of the seam, it can no longer be recognized after applying the decorative foil and the base covering that the can body was brought into the desired shape using seams. With cylindrical can bodies, a rectangular sheet is shaped into a can jacket with a longitudinal seam. But it would also be possible to assemble the can jacket out of two or more jacket pieces with two or more longitudinal seams so that if need be a jacket deviating from the cylindrical shape arises. The deviation from a circular cylindrical shape can arise in the cross section as well as in the longitudinal direction.
In order to be able to hold a decorative foil extremely securely on the can body even on the upper end of the can, an annular covering element is also provided there. This upper covering element is formed in connection with aerosol cans if need be from a sub-region of the valve or from a part fastened onto the valve seat. It is obvious that it can also be fixed in position on the upper end of the can analogously to the base covering through a seal connection, a latching connection or a welding connection, especially with at least three laser welding points, wherein this part covers the upper foil end and therewith protects it from tearing off.
Covering the foil end on at least one end of the can, especially below, makes it possible to dispense with cutting the foil or foil jacket exactly to size in the direction of the axis of the can without in this way an unsightly end being able to make an appearance. Moreover, folds that could form on strongly necked end regions are covered by the base covering and/or by the annular covering element.
Embodiments should also be included in which the base covering lies directly on the base with a surface adapted to the shape of the base and is in particular sprayed directly on the base as an injection molded component.
The solution of the embodiments of the invention opens up new configuration possibilities for cans. Moreover, simplifications in can manufacturing result, allowing the cans to be assembled directly at the filling site. This has the advantage that the space-consuming transport of empty cans from a facility for manufacturing cans to the various filling facilities can be dispensed with. The cans are, for example, assembled from a flat sheet metal piece from which the jacket is formed, from a base component, an upper end component, and a base covering, along with a decorative foil. The base elements, the upper end elements and the base coverings can be stacked with little free space and can consequently be transported in a space-saving manner like stacks of pieces of sheet metal and foil rolls.
Further advantages, features and details of the invention will become evident from the description of illustrated exemplary embodiments given hereinbelow and the accompanying drawings, which are given by way of illustration only and thus are not limitative of the present invention, wherein:
The decorative layer 4 can be constructed as a coating on the exterior of the can wall 2 in the form of at least one layer of paint as well as in the form of a decorative foil. The decorative layer 4 extends preferably at least up to the outer edging of the base covering 7. In the embodiment represented, the decorative layer 4 is somewhat overlapped by the base covering 7. In this way, the metal layer 5 can be prevented from being accessible in the base region. A danger of corrosion is consequently ruled out. The flat sheet material of the base covering 7 has a layer thickness of at least 0.02 mm, preferably, however, in the range from 0.08 to 0.8 mm, especially from 0.2 to 0.6 mm. In this way, the strength necessary for different mechanical stresses can be guaranteed.
The base covering 7 includes a main region 7a, surrounded by the contact region 7b or by the inner edging of the seal connection, that is basically constructed flat and in particular includes the printout of a bar code. The base covering 7 includes a tear-apart device if need be that is constructed somewhat in the form of a weakened tear apart line in the main region 7a. By tearing along the tear-apart line using a strap, a part of the main region 7a of the can can be removed or at least swung out. Winning information can be applied on the interior surface of this element that becomes accessible via the tearing. A base covering 7 that can be torn off enables effects that permit advertising.
In accommodating a base covering 7 that can if necessary be fed in from the side, the feeding apparatus 13 is arranged over the sealing surface 10a. After a can body 1 is inserted into the centering apparatus 11, the base covering 7 is moved by the feeding apparatus 13 toward the base 3. Subsequently the annular sealing surface 10a presses the contact region 7b against the edge region 3b until the heat administered has attained the desired sealing connection 8S It is obvious that the retaining apparatus and the sealing apparatus can be configured in accordance with solutions from the state of the art. In particular, it would also be possible to provide a retaining device that retains the can body solely from an end face and/or holds the latter with the base upward.
In order to implement the sealing connection between the can base and the base covering, at least one processing station is provided, which preferably includes a rotary table, to which is allocated sealing apparatuses rotating along with it. In this manner, the sealing can be conducted during the rotary motion of the rotary table. Such a processing station can, for example, be arranged in the filling operation before or after filling.
If the decorative layer 4, especially the decorative foil, knot extend to the upper edge of the can, an upper covering element 14 can be arranged on the upper end of the can, at least covering the can end region without decorative layer. If the can body is made of three parts, an upper end piece with the valve seat must be fixed into position on the jacket element 1a. In accordance with the state of the art, this is done with a folded seam or if need be via welding (EP 208 564 B1). The unattractive seam region thereby arising between the upper end element and the jacket element 1a can be covered by the upper covering element 14. In the case of an aerosol can, the upper covering element 14 is an element that is connected to the valve and always rests on the can following insertion of the valve. By providing covering elements 7, 14, three-piece cans can be furnished in which the consumer cannot recognize that the can body 1 is composed of various parts. Basically all known types of connection for tightly connecting can elements can be used.
In the embodiment in accordance with
If the can body is provided with a decorative foil, the base covering 7 and if necessary also the upper covering element 14, can be used to protect or firmly clamp the lower or upper foil edge. In this way, the danger of a decorative foil loosening can be substantially reduced. Even welded seams in the longitudinal direction of the can can be covered with a decorative foil. A can jacket that is formed by bending and welding, especially laser welding, can already receive a special shape by cutting the assembled elements to size. Because the material of the at least one metallic sheet material shaped into the jacket is not hardened by transformation steps, the jacket can at least be transformed regionally by altering the periphery. In this way, aesthetically attractive cans can be formed that can be provided with a shrinking decorative foil before or if necessary after transformation. Consequently, new configuration possibilities result.
In the represented embodiment, a decorative layer 4 in the form of a decorative foil 4, is situated on the exterior of the can body 1. The decorative foil 4′ is shrunk fast before the base covering 7 is fixed into position on the can body 1. The lower edge of the decorative foil 4′ need not be exactly cut to size because it is covered by the base covering 7. It extends at least somewhat into the connection region 3b′, but can also project somewhat over the edge of the jacket element 1a. The seal connection must consequently be at least partially constructed between the exterior of the decorative foil 4′ and the contact region 7b with a sealed connection between the contact region 7b and the connection region 3b′. The decorative foil 4′ should thus adhere sufficiently well to the connection region 3b′ For this, sealing layers are present approximately in the connection region on both sides of the decorative foil, which guarantee a fast connection due to the sealing process. The transition from the jacket element 1a or from the can wall 2 to the base covering 7 is constructed in the form of a circular segment in longitudinal segment or is drawn in toward the interior and preferably has a curvature radius ranging from 1 to 6 mm, especially basically 3 mm. This radius permits in comparison to corners an unimpeded conveyance even over short steps. If need be, the base covering 7 forms a base wherein a standing can body 1 is only in contact with the support surface through the base covering 7.
Because it is possible to omit a seal or welded connection, the base covering 7 does not need to be sealable or weldable. Consequently, any desired plastics or even metals, especially coated and/or magnetic metals, can be used to manufacture the base covering. The spring lips 7f can be constructed in any desired form and are provided at least at three points basically equally spaced in the peripheral direction. Because positioning a latching element without a sealing or welding device can be conducted by a single linear motion of a pressing element, the method as well as the device for fixing a latching base covering in position are extremely simple.
Exemplary embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 64/03 | Jan 2003 | CH | national |
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/CH02/000609 which has an International filing date of Nov. 13, 2002, which designated the United States of America and which claims priority on Swiss Patent Application number 158/02 filed Jan. 30, 2002, the entire contents of which are hereby incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CH04/00004 | 1/9/2004 | WO | 5/1/2006 |
