DE19502992A1 - Process for producing hollow bodies and hollow bodies according to this method - Google Patents

Abstract

The outer surface (1) of a container, for example an aerosol can, is produced from strips of a flat material that surround the hollow space (3) inside the container and are wound so as to overlap in an overlapping area (2). The overlapping area (2) corresponds to at least one circumference, but preferably to at least two circumferences of the substantially cylindrical outer surface (1). A joint is provided between at least two overlapping layers in at least part of the overlapping area (2). The joint is ensured by gluing, preferably with an epoxide glue, by a seam, in particular a welding seam or an edge-raised seam, and/or by stretching a shrinking foil on the outer surface (1) of the container. An essential advantage of this overlapping seam is that friction forces are generated between the contacting areas of the flat material that forms the outer surface (1), in particular when the container inner pressure is increased. The joint must thus resist to smaller forces than it would be the case if there was no overlapping. In addition, the flat material may be completely printed, coated and/or lacquered before winding.

Description

The invention relates to a method according to the sayings 1 and 6 and on a hollow body according to the claim 7.

To accommodate food, cosmetics and materials, such as colors, is a multitude of hollow bodies, or Ge well known. These vessels usually have one Chen cylindrical central area, a bottom closing Floor area and an upper at least partially final Deck area. The manufacture of the vessels depends both of the vessel material used, and of the Ver type of consumption of the material absorbed in the vessel. So be for example aerosol cans made of aluminum and tinplate, Tinplate food cans and aluminum tubes or plastic.

In the manufacture of aerosol cans according to the state the technology first an approximately disc-shaped blank Kind of cold extrusion through a piston in a mold cold formed into a hollow cylinder. To get the necessary ver To ensure formability, it must be soft or very pure, Aluminum are used. According to the compared to Small strength aluminum alloys of pure aluminum a larger wall thickness is chosen, which means an un wishes high material requirements. The hollow cylinder becomes after pressing any mold release agent, fats and other lubricants, chips, etc. using a cleaning agent agent and / or hot water rinsed and cleaned and primed after cutting to length. After drying or baking The basis is printing using expensive high-, or gravure printing machines, as well as the subsequent drying in a second oven. By applying and drying one The decor is protected over varnish so that when connecting  the deformation process for the neck part no damage of the decor is created. Both for cold extrusion and also for subsequent cleaning, coating and / or Print outside with a decor are investment and personnel-intensive plant parts necessary.

When producing tinplate vessels, it turns white Sheet piece bent into the shape of a cylinder jacket and with closed with a seam along a surface line. ground and lid are befe with circular seams on the jacket increases. Seams on tin cans or if necessary The disadvantage of aluminum cans is that they form weak spots, protrude and therefore about the dense insertion of the soil and of the lid, and possibly due to corrosion to be damaged. To avoid protruding seams, butt welds are provided, at least need further processing outside. To generate enough tight butt welds must be an un wishes to have a large wall thickness. It has shown that cans with a seam along a surface line are stable only up to internal pressures of around 8 to 10 bar. At higher internal pressures, cold-extrusion is used Used cans.

Flanged and / or welded seams are to be closed the cylinder jacket of vessels with high internal pressures, such as such as aerosol cans, not suitable, as they may not from the high pressures Withstand. In addition, when coating an inner seam Tool with minimal necessary for the machining process Find outside dimensions inside the vessel, which means that the vessels must have a minimal inside diameter sen, which is from experience about 45 mm.

The vessel with a seam must, for example, for reasons of Food hygiene and / or to prevent the seam from corrosion protect be coated inside. The cylindrical coat needs a primer and a label on the outside,  or a graphic identification. By marking printed directly on the vessel can be prevented that after a possible loss of a label of the vessel is no longer ascertainable. For printing on cylindri Vessel outer surfaces are high, or, if necessary Gravure printing with one or more colors used. Printing stations for printing on the cylindrical outer surfaces but are very expensive and require a lot of personnel connected.

The object of the invention is therefore pressure-resistant Vessels with closed lateral surfaces with little work effort to manufacture.

The solution according to the invention provides that the closed Shell of a vessel made of a strip of flat material is produced, which surrounds the cavity of the vessel and in overlapping a predetermined overlap area winds, or is arranged. The overlap area ent speaks at least one extent, but preferably at least two circumferences, in particular essentially cylindrical Lateral surface. At least in part of the overlap area ches is a connection between at least two overlap the locations provided. This connection is made by a Gluing, preferably an epoxy gluing, a seam, in particular a weld seam or a flanged seam and / or the covering of a shrink film guaranteed. A major advantage of the overlap connection especially with increased internal vessel pressure, frictional forces between the abutting areas of the jacket forming flat material in appearance. The connection must thus withstand smaller forces than this without overlap pung would be necessary.

If the overlap is at least one circumference, the thickness of the strip of material only has to be half the desired wall thickness. With the material strip is it a thin sheet or one  Plastic strips. With material strips of a standard thickness can be different due to different wrapping numbers Wall thicknesses are generated. Since there is no welding can be tet and / or at least not with the interior of the vessel is in contact, internal treatment of the Seam.

The strips of material are thus preferably before Wraps completely printed and / or coated, or with Decor and interior varnish provided so that in the wrapped form no more surface treatments are necessary. It understands it goes without saying that even electrophoretic treatments can be provided. The coating, or treatment, it does not have to cover the entire strip of material stretch, but extends about for cost reasons preferably only to those in the wound state of areas of the material accessible from the inside or outside streaking.

By rolling wide material webs or sheets, for example prints, if necessary coated, and only then in Cut strips of material of the desired width and length be, this leads to a simple and extremely costly cheap vessel production. In addition, coatings, e.g. B. with foils, possible, for example, on the inner wall of the ge pressed vessel are not possible. Because on a cold extruding the outer surface can be hard tere alloys and thus for constant stability thinner walls can be provided. This will make it Weight of the containers or cans reduced.

There are further advantages of the solution according to the invention in that vessels with very small diameters and also those with conical outer surfaces can be produced. The shape of the vessel from a wrapped sheet of flat material fen is formed by the formation of the strip of material that Winding and if necessary by a subsequent Ver shaping process determined. The shape is by no means open  cylindrical, conical or rotationally symmetrical lateral surface Chen restricted. It turns out that the shape thanks compared to cheaper processing of the material strip the state of the art can be expanded in many ways. Ins Special ones can be pressed in, for example, surface structures to those who shape both the external appearance of the vessels as well as by snapping them into the overlap area adjacent material strip areas Increase the strength of the connection in the overlap area.

The method according to the invention has in particular in the manufacture Positioning aerosol cans the advantage that it is both for Production of cans from tinplate as well as from aluminum is suitable and that nö to carry out the method term devices essentially not to edit depend on the material. Have the wrapped tin cans no seam at risk of breakage and can therefore also be used inside pressures above 8 to 10 bar can be used. Aluminum cans have so far not been analog due to welding problems built up to tin cans. The new manufacturing ver driving expands both the use of Tinplate as well as aluminum or aluminum alloys.

Even plastic strips can with sufficient overlap and good gluing to vessels, or closed vessel man surfaces with the necessary stability properties be wrapped. To increase stability, preference is given to have at least one reinforcing element in the overlap area ment arranged.

Long fibers, fabrics, reinforcement-like structures or preferably thin Sheets, especially perforated sheets in question. Are preferred the reinforcement elements completely from the jacket wall forming material strips surround and therefore neither come with still in contact with the interior of the container. To the Connect the reinforcing element with the adjacent ones Areas of the material strip may be connected  tion materials, such as glues or resins, or the Connection is created by a thermal treatment that areas of both sides of the reinforcement elements Connects strips of material with each other. When using of combustible and / or biodegradable ren strips of material and reinforcing elements made of Na Turf fibers are ge that can be easily disposed of ecologically barrels.

When further processing the wound and glued man different process steps that the each because of the vascular design are adapted, who provided the. For example, the at closed lateral surface a lid by means of a flanging and / or Welded connection used. So you get about three-piece cans in the style of the well-known tin cans, but with the cylindrical sleeve casing due to the wick lamination and gluing is more stable with the same wall thickness, or the stability of conventional rifles with thinner tubs reached.

When producing tubes, one end of the jacket is used preferably with a closable opening End part and the other end by flattening and on bring a folding closure closed. The final part is glued or welded to the outer surface, or in a narrowed end part of the same is pressed in or attached to it flanged.

In the manufacture of spray cans or aerosol cans Shell surface preferably at least at one end decorated, or by compressing, drawing in processing tight. For this purpose, a tool with a conicity is used at least partially corresponding hollow shape in for the shaping of rivet heads in a manner known per se along a central hypocycloid rosette point of the conical vault and against it working jacket end pressed. This conification process  has not been used to form cans until now, but is also with a non-wrapped can jacket with conventional cans, when tapering reversible. Instead of many different sized shapes Sharing only a part that is movable is required. This conifying process with the rosette-shaped Tools should therefore also be regarded as an independent invention ten.

At the outlet end of the can, the conification is trained det that a valve can be attached. The given if provided, conification at the closed end of the can is designed so that a floor can be attached can. The connection between the bottom and the coat includes preferably a flare, especially in the interior of the can protrudes and thus the external appearance of the can not be impaired and also withstands high internal pressures.

Deep-drawing may also be used for the butting can be provided by reverse cold extrusion.

The drawings explain the invention schematically illustrated embodiments.

Fig. 1 shows a perspective illustration of a wound Zy relieving mantels,

Fig. 2 plan view of a step-free wound Zy relieving coat,

Fig. 3 Horizontal section through a vessel jacket with a reinforcing element

Fig. 4 vertical section through the lower portion of a spray can with a non-rotating ground,

Fig. 5 Schematic representation of a hypocycloidally movable conifying tool.

Fig. 1 shows an essentially formed from two windings of a strip of material, preferably cylindrical, Wan extension 1st An overlap region 2, the strip of material abut each other in the two areas extending we sentlichen once around the area enclosed by the jacket 1 hollow space. 3 At least in a part of this overlap area 2 , in particular along a surface line parallel to the cylinder axis, a connection between abutting material strip areas is provided.

The connection is preferably an adhesive connection, in particular with epoxy, or else a soldered or welded connection. The forces acting on the connection are reduced by adhesive frictional forces in the overlap area 2 , so that the stability requirements for the connection are not particularly high. This applies in particular to aerosol cans with increased internal pressure. If necessary, it is sufficient to provide a connection along an outer end 4 of the material strip. If a weld or solder seam is attached at this point, this does not affect the inner wall directly adjoining the cavity 3 , that is to say that no cleaning and / or coating has to be carried out inside after the connection.

Fig. 2 shows a wound can jacket, in which the inner and outer ends 5 , 6 of the strip of material abut a first and a second stop 7 , 8 , respectively. The two stops are preferably formed by a generated by means of two fold lines, radial section of the strip of material. The selected design of the stops ent creates a can wall on which neither the outside nor the inside of a strip of material forms a protruding paragraph. In addition, the presence of the inner end of the strip 5 at the first stop 7 prevents the inner end 5 from moving against the overlap region when the forces acting radially inwards on the can or possibly protruding into the hollow space 3 . A vessel jacket with a substantially constant thickness around the entire interior has the advantage that even when inserting the lid and or the bottom part, in particular, for example by means of a flare connection, no problems arise.

To prevent the outer end of the strip of material protrudes, can instead of being placed against a stop can be seen that at least this end worked like this is that it runs out thinner and so hardly from the Jacket outer surface protrudes.

Fig. 3 shows a vessel jacket 1 with a reinforcement element 17 , which is arranged in the overlap region 2 and thus increases the stability of the jacket. The reinforcing elements include long fibers, fabrics, reinforcement-like structures or sheets, especially perforated sheets in Fra ge. Preferably, the reinforcing elements are completely surrounded by the material forming the jacket wall and thus do not come into contact with the environment or with the container interior 3 .

The material strip is coated and / or consists of egg material that is not from the product contained in the container is attacked. Because stability comes from reinforcement the material strip itself can be guaranteed formed from substances with poor stability properties his.

Fig. 4 shows a variant of a bottom closure of the cylindrical wall 1 with a flanged bottom part 9. For this purpose, the lower end region of the cylindrical wall 1 is butted after the base part 9 has been introduced, pressed in and connected with a flange 10 to the base part 9 in such a way that no edge is visible, or the flange 10 lies inside the can. This creates a can bottom of the shape essentially the conventional Do senboden, which are cold pressed from a single piece, speaks ent, but has a two-part structure analogous to the tin cans.

Fig. 5 shows a conification with essentially only one conifying tool 11 , which by various actuation rods 15 excited by motions, approximately the cylindri cal upper end 12 of the wall 1 butted, as is usual with spray cans. A central opening 12 a is formed from that a valve can be used. The tool 11 summarizes a rotationally symmetrical recess 14 with respect to a tool axis 13 , which has the diameter of the cylinder jacket in an entry region 14 a. In an inner region 14 b, the depression 14 is conical. At the beginning of the conifying step, the entry area is guided over the upper edge of the cylinder and is deformed conically inwards by a roset-shaped or hypocycloid, movement B1 of an end of the actuating rod remote from the tool 11 . So that the conical deformation to the inside does not become too strong, a painting and shape-limiting part 16 is preferably arranged in the interior of the wall 1 .

The movement B1 to form the transition from the cylindri's to the conical shape preferably provides paths of the actuating rod end, which do not lead around the axis 13 . In addition to the rosette-shaped movement B1, the tool 11 is also gradually guided somewhat along the axis 13 against the cylinder piece 1 to be machined, or the holding part 16 . The effective movement of the workpiece results, preferably, by the interaction of the actuation by means of the actuating rod 15 and the guide on the part 1 to be formed, or on the holding part 16 .

In order to form the area against the opening 12 a, the inner area 14 b of the recess 14 must be pressed against the conical area which has already been formed. For this purpose, the actuation rod 15 is preferably moved according to a schematically represented movement B2 about the axis 13 . The sequence of movements required for forming the upper end region of a spray can is complicated, but preferably only requires a tool 11 . The shaping is carried out by compressing, drawing-in machining using a tool with a hollow shape which at least partially corresponds to the conical curvature.

Claims (10)

1. A method for producing can-like or tube-like containers, in particular aerosol cans, in which only a closed jacket wall ( 1 ) is formed for the container and then a bottom ( 9 ) and a final upper part ( 12 ) are formed, characterized in that that the jacket wall ( 1 ) consists of a flat material strip, which is wound overlapping over a predetermined overlap area ( 2 ) before the bottom ( 9 ) and the final upper part ( 12 ) are formed. 2. The method according to claim 1, characterized in that the overlap region ( 2 ) is formed such that it corresponds to at least one extent of the closed jacket wall ( 1 ), preferably at least two circumferences and / or that at least one end of the strip of material preferably on an associated Stop ( 7 , 8 ) is brought into impact, or possibly processed so that it runs out thinner and so hardly protrudes from the outer surface of the jacket. 3. The method according to claim 1 or 2, characterized in that in the overlap area ( 2 ) a connection, preferably as a glue, in particular with epoxy, or a soldered or welded connection is attached and / or that around the closed jacket wall ( 1 ) a shrink wrap is attached. 4. The method according to any one of claims 1 to 3, characterized in that at least one of the following features is provided,

• a) the strips of material are at least partially treated, coated and / or printed, or provided with decor and interior lacquer, even before winding; and
• b) at least one reinforcing element ( 17 ) is arranged in the overlap region ( 2 ) during winding.

5. The method according to any one of claims 1 to 4, characterized in that the formation of an end part ( 12 ) comprises a conification process on the cylinder part ( 1 ) and / or that the formation of the bottom of the vessel zen, preferably with flanging, one essentially comprises rotationally symmetrical base part ( 9 ). 6. A method for conifying can-like or tube-like containers, in particular aerosol cans, in which a substantially cylindrical shape is narrowed at one end by jamming, drawing-in processing, in particular for a method according to one of claims 1 to 5, characterized that a tool ( 11 ) with the conical curvature ( 12 ) at least partially corre sponding hollow shape ( 14 ) in a manner known per se for the shaping of Nietköp fen along a hypocycloid Ro sette (B1, B2) with center in the center of the conifi cation bulge to be led. 7. hollow body with a closed wall ( 1 ), Herge provides according to a method according to any one of claims 1 to 6, characterized in that the wall ( 1 ) consists of a wound flat material strip which over a predetermined overlap area ( 2 ) is arranged overlapping. 8. Hollow body according to claim 7, characterized in that the overlap region ( 2 ) corresponds to at least one circumference of the closed jacket wall ( 1 ), preferably at least two circumferences and / or that at least one end of the material strip preferably on an associated stop ( 7 , 8 ) is pending, or possibly becomes thinner and hardly protrudes from the outer surface of the jacket. 9. Hollow body according to claim 7 or 8, characterized in that a connection, preferably a gluing, in particular with epoxy, or a soldered or welded connection is provided in the overlap region ( 2 ). 10. Hollow body according to one of claims 7 to 9, characterized in that at least one of the following features is provided,

• a) the strips of material are preferably made of aluminum, in particular an aluminum alloy, optionally made of tinplate or plastic;
• b) the strips of material are at least partially treated, coated and / or printed, or provided with decor and interior lacquer before winding; and
• c) in the overlap area ( 2 ) at least one reinforcing element ( 17 ), preferably as a thin sheet, in particular as a perforated sheet, but optionally as fiber material or fabric, is arranged.