DE2127406A1 - Pressure-proof container - Google Patents

Description

PATENT LAWYERS

HELMUT SCHROETER KLAUS LEHMANN

DIPL.-PHYS. DIPL.-ING.

8 MUNICH 25 LIPOWSKYSTR. 10 Z. I 2. 7 4 O

00-17

Crown Cork & Seal Company, Inc. June 2, 1971

Pressure-tight container

The invention relates to so-called seamless containers, and in particular it relates to containers having a drawn one-piece container body that is seamless Sidewall and an associated bottom comprises and at the top of the seamless sidewall with a double beaded end wall is provided.

Such containers come in contrast to the usual ones Containers with a side seam for aesthetic reasons in the field of beverage packaging like beer and the like. a special meaning. Until now, the beverage and brewery industries have used containers with Longitudinal seams and two double-beaded end walls are predominantly used, but the appearance of these leaves them common Container left a lot to be desired. In particular, the presence of a longitudinal seam makes printing and printing more difficult Label the containers or cans. Considerable efforts have been made to achieve that Longitudinal seams protrude outwards as little as possible in order to impair or interrupt the labels and To reduce lettering to a minimum, but have the longitudinal seams even with the most pleasing beverage or beer cans still looks very ugly.

In order to avoid the unsightly longitudinal seam in these beverage or beer containers, the

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extensive tests have been carried out over the years with the aim of to develop a container comprising a container body with a seamless side wall and a continuous side wall Floor includes. Depending on whether the metal used is aluminum or steel, can divide these experiments into two groups.

Since aluminum has a high ductility, the use of aluminum for making seamless cans is becoming more and more popular deemed appropriate. Because of this great deformability, aluminum can be deep-drawn and repeatedly redrawn, and the walls of containers can be ironed or smoothed; these operations can be done with great Carry out ease, and you can therefore bring the material into almost any desired shape. For example, are U.S. Patents 3,349,956 and 3,343,670 show various embodiments of bottom sections of seamless liners made by drawing from raw aluminum parts will. In Fig. 3 of these US patents, a particularly complicated embodiment is shown by which the high pliability or ductility of aluminum is illustrated.

Although aluminum is used on an industrial scale to make seamless containers, the aluminum adheres certain disadvantages that result in only a limited uptake of aluminum by the cans for beer and have led other beverage manufacturing industries. The main disadvantage is undoubtedly the high cost of aluminum. Since seamless cans are only used once in the field of drinks, their price is allowed constitute only a small fraction of the selling price of the product, and therefore it is very important that have the seamless liners manufactured at a minimal cost.

Another disadvantage of aluminum is that it only takes account of the internal pressure generated by the contents of the can

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offers little resistance. As a rule, a beverage or beer can must have an internal pressure of about Withstand 7 atmospheres. When the resistance is so low that the container bottom at a lower internal pressure can be pushed through to the outside, such a can is not suitable for carbonated drinks such as beer and soft drinks. In some cases where the containers had a higher compressive strength, that was The stability of the container in an upright position is impaired. In other cases the bottom of the container was with formed a greater wall thickness, so that there was a higher consumption of expensive aluminum.

In view of the aforementioned difficulties encountered with seamless aluminum containers considerable effort has been made to use steel or coated steel, as is the case with the usual ones Bushings with longitudinal seams in most cases is common. Despite the lower cost of steel in comparison however, seamless steel liners are not produced on a large industrial scale and on the aluminum Brought to market.

One of the reasons that seamless steel liners have not heretofore been adopted is that it is difficult to provide the inner surface in the area of the floor with a coating. The one to be observed with sheet steel correct drawing angle determines to a certain extent the shape of the bottom of the can. With the required form of the Soil, it is difficult to apply a coating. In the case of aluminum cans, the coatings are not particularly good critical importance to; However, this does not apply to cans made from 3talii. .Venn sockets made of steel do not match a flawless Can be provided with a coating, they are unsuitable for packaging 'Hier and other beverages. Further Of course, the bottom of the can must be designed in such a way that it withstands an internal pressure of about 7 atmospheres. To with the up

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now known rifles have sufficient resistance To achieve this, you have to process raw parts made of very thick sheet steel. As a result, you obviously need one larger quantities of steel, which leads to an increase in costs, and / or the side wall must be ironed or ironed to a greater extent to accommodate the thickness of the side wall to reduce to a considerable extent compared to the thickness of the strong floor. Have in view of this the hitherto known drawn steel containers in the manufacture of cans for soft drinks and beer not imported to a significant extent.

It is now the object of the invention to provide a seamless steel container for the branches of industry which pack beverages and beer in cans, which meets the requirements of the practice. The aim is to create an improved seamless steel container which can be provided with a uniform and perfect coating. Another aim is to provide an improved seamless steel container that can withstand high internal pressure. Next, an improved seamless ^s tahlbehälter is to be created, which has a wide supporting base, which prevents the falling of the container. Finally, a container of the type mentioned is to be created, for the manufacture of which only a minimal amount of steel is required.

A steel container constructed in accordance with the invention which can withstand an internal pressure of about 7 atmospheres comprises one one-piece container body with a seamless, substantially cylindrical side wall and one on its lower End of adjoining floor. The bottom includes an outer substantially frustoconical surface extending from the Sidewall extending downward and inward to the container axis, an annular bead that attaches to the first frustoconical surface connects and an annular Forms support surface for the container, an inner substantially frustoconical surface, which extends from the annular

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shaped bead extending upwards and inwards to the container acbae, and an inwardly curved central bottom surface extending from the inner frustoconical surface extends upward and inward to the axis of the container.

So that a perfect and even coating can be applied to the inner surface of the sleeve in the area of the bottom, the inner frustoconical surface can extend at an angle of over 5 ° upwards and inwards to the axis of the sleeve. If such an angle is chosen, the inner surface of the ring-shaped bead becomes accessible, so that the creation of a uniform and perfect covering is guaranteed even if the frustoconical surface is inwardly and downwardly at an angle of less than 50 ° to the liner axis extends.

In order to ensure the necessary compressive strength without sacrificing stability, the central The bottom surface is curved inwards so that it is frustoconical to a point above the upper edge of the outer Area extends. It has proven to be expedient here to face the edge of the curved central surface off the supporting surface of the annular bead upwards by an amount that is at least $ 50 the height of the _ outer frustoconical surface corresponds. Furthermore, ™ it has proven to be useful to choose the radius of curvature of the curved surface so that it is twice the radius does not exceed the annular wing.

Embodiments of the invention are described below with reference to the drawing.

Fig. 1 is a partially broken away side view of a container according to the invention.

Fig. 2 shows in an enlarged partial section the bottom and the lower part of the side wall of the container according to Fig. 1.

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Figure 3 is similar to B ¹ Ig. 1 but shows the bottom and the lower part of the side wall of a container of known type.

4a to 4e illustrate various stages in the manufacture of a container according to the invention Mg. 1.

In the preferred embodiment of Mg. 1 comprises the container 10 made of steel has a one-piece container body 12 with a side wall 14 and a floor 16 connected to it. An end wall 18 is through double flanging connected to a drawn-in section of the otherwise essentially cylindrical side wall 14.

The bottom 16 is designed according to several important features of the invention so that it can easily be with a Can be provided with a coating, can withstand internal pressure and is dimensionally stable. ' More precisely, the bottom 16 comprises a first outer frustoconical surface 20 extending from the side wall 14 extends downward and evenly inward, an annular supporting bead 22, which extends to the outer frustoconical surface adjoins, a second inner Truncated cone-shaped surface 24, which extends from the bead 22 upward and uniformly inward, and one arched central portion 26 extending from the inner frustoconical surface 24 to the axis of the container 10 extends.

Further details of the bottom 16 are described below with reference to Mg. A very important feature of the invention is that it makes it possible to obtain a uniform and perfect coating of, for example, modified Vinyl acetate or a vinyl chloride polymer onto the inner surfaces of a seamless container with the help of two apply separately electrically controllable spray nozzles 27 of known type. The typical shape of the one produced by the nozzles 27 Spray jet is in Fig. 2 by lateral and after

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arrows 28 pointing downward are indicated, which run in the direction of the side wall 14 and the bottom 16. It has shown that the shape of the soil shown in Figo 2 the emergence a uniform and flawless coating on the floor 16 is guaranteed if the spray nozzles 27 are known Art is being worked on.

When covering the base 16, a difficulty arises on the inner surface of the annular bead 22, and this difficulty increases as the bulge becomes more concave. To some extent, the concavity of the Bead 22 is determined by the angle A between the outer frustoconical surface 20 and the axis of the container 10. As the angle A becomes larger, the concavity of the bead decreases so that a coating can be applied more easily. The choice of a larger angle A, however, leads to a reduction in the width of the base or base carrying the container. to a reduction of the radius R-g through the annular Bead 22 formed support. If one decreases the radius R-O, the container 10 becomes less stable, i.e. it falls over more easily. If, on the other hand, one chooses a smaller angle A, not only the concavity of the annular one increases Bead 22, but such an angle is not compatible with the approximately 45 ° drawing angle of steel, and he also nests cans impossible, in which the upper part of the side wall H is drawn in in the manner shown in FIG. For this The choice of angle A is limited to the range from 30 ° to 50 °, with an angle of 40 being preferred. In this area for the choice of the angle A, it has been shown that the inner surface of the annular bead 22, the Shape partly due to the angle of inclination of the frustoconical Surface is determined, can be covered properly and evenly, if you have a suitable angle B between the inner frustum surface 24 and the axis of the container 10 provides. More specifically, it was found that the angle B must be in the range of 5 ° to 20 °.

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Because of the large width of the support, which is determined by the radius R _B , which can correspond to about 80% of the radius Rg of the side wall 14 of the container, and which is slightly larger than the radius R _E. Of the edge of the central bottom surface 26, there is at internal pressures of up to about 7 atmospheres or more, there is a considerable risk of the container bottom being pushed through to the outside. In order to avoid this risk, the central bottom surface 26 is curved inwards according to a certain radius of curvature Rq and is designed so that it extends up to a certain height Η. With a radius of curvature Rq that is not greater than twice the radius <.- n and preferably slightly greater than the container radius R ", and with a height Ho of the recess at the edge of the bottom surface 26 that is greater than 50 $ of the total height H. _{Q of} the truncated cone surface 20, the central bottom surface 26 protrudes upward beyond the upper edge of the truncated cone surface 20. If the central bottom surface 26 is curved in this way and offset upwards, its compressive strength is sufficient to combine that it is pushed through to the outside. It is also believed that the central bottom surface 26 facilitates the application of a uniform and perfect coating to the inner surface of the annular bead 22.

Certain dimensions for a container according to FIGS. 1 and 2 are given below as examples, in which the Thickness of the central wall surface is about 0.299 mm.

Angle A = 40 ~ mm Angle B «15 ° mm ^H R ⁼ 5.15 mm ^H 0 = 8.64 τητη H ₁ = 12.55 mm ^R E = 25.45 τητη ^R B = 26.15 TTITTI R ₃ = 55.00 ^R 0 ⁼ 40.00

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In ffig. Figure 5 shows a seamless container of known type made of aluminum. As mentioned, coating the bottom of a container made of aluminum is not as important as it is for containers made of steel. To Pig. 3, it should be noted that the angle B between the inner surface 44 of the bottom and the axis of the aluminum container is approximately 0 and the angle A between the outer surface 40 and the container axis is 37.5 °. With regard to the risk of the bottom being pushed through, it should be noted that the inwardly curved and upwardly offset central bottom surface 46 does not extend upwards beyond the upper edge of the outer surface 40, the height of which is shown at Hq, and that the height EL of the Recess at the edge of the central bottom surface 46 does not correspond to _{at least 50 $ of the height H Q.} The radius of curvature Rq of the curved central surface 46 is more than twice as large as the radius Rn and almost twice as large as the radius Rg. Finally, since the angle B is zero, the radius R ™ of the edge of the central bottom surface is substantially the same Radius Rg.

According to the above description, the shape of the known containers made of aluminum differs considerably from the shape of the steel container according to the invention according to FIGS. 1 and 2, so that there are significant differences in the application of coatings and the penetration resistance of the floor result. The following tables show the differences in the penetration resistance of the bottoms of steel containers recognize with differently designed base parts.

Container I:

Angle A = 15 ° mm Angle B = 15 ° mm % = , 5.00 mm H ₀ = 4.52 mm H ₁ = 15.85 mm ^R E = 27.25 mm ^R B ⁼ 50.20 mm R ₃ = 55.00 Rn = 44.40

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Container II:

-10-

Buckling pressures in floors with different wall thicknesses

Wall thickness = 15 ° pressure atü 0.300 mm = 15 ° 6.88 atü 0.284 mm 5.00 6.75 atü 0.272 mm 4.52 5.91 Angle A 12.30 Angle B 27.25 ^H R ⁼ 30.20 mm ^H 0 = 33.00 mm 51.75 mm ^R E ⁼ mm mm R ₅ = mm H = mm

Buckling pressures in floors of different wall thickness

Container III:

Wall thickness mm 15 ° pressure atü 0.297 mm 15 ° 6.75 atü 0.294 mm 5.00 6.75 atü 0.292 mm 4.52 6.75 atü 0.266 mm 19.95 6.05 atü 0.279 A = 27.25 5.91 angle B = 30.20 angle 33.00 H _R = 64.20 mm ^H 0 ⁼ mm mm ^R E ⁼ mm ^R B ⁼ mm Rg = mm mm

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, Container IVj container V:

Buckling pressures in floors with different wall thicknesses

Wall thickness pressure atü pressure atü 0.300 mm 7.03 atü 8.85 atü 0.297 mm 6.88 atü 7.37 atü 0.294 mm 6.88 atü 7.03 0.289 mm 6.47 Angle A = 40 ° Angle B = 15 ° mm
mm % = 4.87 mm mm H ₀ = 8.32
H ₁ = 13.75 mm
mm mm R _E = 23.60 mm mm R _B = 26.15 mm mm R ₃ = 33.00 mm mm R ₀ = 33.97 mm Buckling pressures in floors
of different wall thickness Wall thickness 0.307 mm 0.272 mm 0.279 mm Angle A = 40 ° Angle B = 15 ° H _R = 5.16
H ₀ = 8.64 H ₁ = 11.06 R _E = 23.45 R ₅ = 26.15 R ₃ = 33.00 R _G = 40.00

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Buckling pressures in floors with different wall thicknesses

Wall thickness print 0.307 mm "9.27 atm

0.302 mm 8.72 atm

0.300 mm 8.50 atü: ¹

0.297 mm 8.72 atm

0.292 mm 8.43 atm

0.287 mm 8.30 atm

0.279 mm 7.24 atm

0.274 mm 7.69 atm

It can thus be seen that the resistance of the floor to bulging increases if a larger angle A is selected for a given wall thickness. It can also be seen that the resistance to being pushed through increases when the curved central bottom surface is displaced further upwards and its radius of curvature R _{n is} small, although siGh results in a lower resistance if the radius of curvature is too small.

A Pig. 1 and 2 by drawing several in Fig. 4a to Fig. 4e performs the steps shown. Sheet steel with a thickness of about 0.30 mm is used as the starting part the blank 50 shown in Fig. 4a is produced. The blank 50 is then drawn into the shape of a Cup 52 and drawn again into the shape of a cup 54 of smaller diameter; on this will the wall of the cup brought into the shape shown in Fig. 4d by further deformation or ironing, so that a tall cup 56 is obtained. Note the in Fig. 4b aaixti shown drawing angle of 45 ° and that of Fig. 4c and Figure 4d shows trailing and wall "bracket" angles of FIG 40. This latter angle of 40 is maintained during the shaping of the arched bottom part according to FIG. 4e, wherein he to the angle of inclination of the outer frustoconical surface 20

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will. Fig. 4e also shows a stamp 58 and one for Arching the container bottom serving die 60, which is shaped so that the bottom 16 is also shown in Fig. 4e Form according to Fig. 2 is obtained. The punch 58 and the die 60 are designed so that they the bottom 16 with the truncated cone surface 20, the annular bead 22, the truncated conical surface and the central bottom surface 26 give the desired shape » The side wall 14 of the semi-finished container 10 can then be trimmed, necked in and flanged before the end wall 18 by double flanging with is connected to the top of the side wall. In the described shape of the bottom 16, the annular bead 22 can on the flat top of the end wall 18 of another similar Support the bushing, although the side wall is retracted in the manner shown in FIG. more details of the various work steps shown in Fig. 4a to 4e are the patent (patent application

; our reference cc-18).

Expectations:

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Claims (1)

-H- AFS P RULES 1. Container made essentially of steel, the withstands an internal pressure of about 7 atmospheres, marked by " that the container has a one-piece container body (12) with a seamless, substantially cylindrical side wall (H) and a bottom (16) adjoining the lower end of the side wall and one by flanging the top of the side wall twice connected end wall (18) comprises that the bottom comprises an outer, substantially frustoconical surface (20), which extends from the side wall downwards and inwards to the axis of the container (10) at an angle in the area extends from 30 to 50, further an annular bead (22) extending from the outer frustoconical surface extends out and forms an annular supporting surface for the container, the radius (R-g) of which is less than 90 $ des Container radius (Rq) on the side wall, an inner, essentially frustoconical surface (24) extending upward and inward from the annular bead towards the axis of the container extends at an angle in the range from 5 to 20 to the container axis, and one opposite the lower end of the Container upwardly offset curved central surface (26), which extends from the inner frustoconical surface above and inside, and that this central surface extends upwards considerably over the uppermost part of the outer frustoconical surface extends out where it reaches the axis of the container. 2. Container according to claim 1, characterized in that the edge of the curved central surface (26) is offset from the lower end of the container nas's above by a distance (Ho) which is at least half the height (H _Q ) of the outer frustoconical Area (20) corresponds. 109886/0267 5. Container according to claim 2, characterized in that the radius (Eq) of the arched central Area (26) is not greater than twice the Hadius (Rg) of the annular supporting area. 4 »Container according to claim 3 * characterized that the V angle (A) between the outer. frustoconical surface (20) and the axis of the container (10) is about 40 °. 5. Container according to claim 4 »characterized in that the angle (B) between the inner frustoconical surface (24) and the axis of the container (10) lies in the range from 10 ° to 20 °, 6. Container according to claim 5, characterized in that the upper end of the side wall (14) is drawn in, and that it is the angle (B) between the inner frustoconical surface (24) and the axis of the container (10) allows the ring-shaped bearing surface to be attached to the flat part of the double flanged Support the end wall (18) of another similar container. 7. Substantially made of steel container which can withstand an internal pressure of about 7 atmospheres without becoming its bottom pushes through to the outside, characterized in that the container is a one-piece Container body with a seamless, substantially cylindrical side wall (14) and one at the lower end the side wall adjoining bottom (16) and a through double flanging with a drawn-in section of the side wall at its upper end connected end wall (18) comprises that the bottom comprises an outer surface (20) which extends downwardly from the side wall and inwardly towards the axis of the container (10), further an annular bead (22) extending from the outer surface and an annular support surface for the container 109886/0267 forms that the outer surface extends so far inwardly that the annular bearing surface on the im can support substantially flat surface of an end wall of a substantially similar container that the bottom further includes an inner surface (24) extending from the annular Bead extending upward and continuously inward toward the axis of the container, as well as one opposite that lower end of the container upwardly offset curved central surface (26), which extends from the inner surface towards extends upward and inward to the axis of the container and upwardly beyond the uppermost part of the outer surface. 8. A container according to claim 7, characterized in that the lowermost edge of the arched central Surface (26) has a radius (Rj,) which is less than 80 $ of the largest radius (Rg) of the container (10) on the side wall (14). 9 · Container according to claim 8, characterized in that the edge of the curved central Surface (26) relative to the lower end of the container (10) is offset upward by a distance (Hr,) which is at least 50 $ corresponds to the height (Hq) of the outer surface (20) between the annular supporting surface and the side wall (14). 10. Container according to claim 9, characterized in that the outer surface (20) is substantially is frustoconical and coincides with the axis of the container (10) forms an angle (A) in the range of 30 ° to 50 °. 11. Container according to claim 10, characterized in that the inner surface (24) is substantially is frustoconical and coincides with the axis of the container (10) forms an angle (B) in the range of 10 ° to 20 °. 109886/0267 Blank page