DE1777099A1 - Device for stretching metal cups to form can bodies - Google Patents

Description

Ie. ELISABETH YOUNG. DR. VÖLKER VOSSIUS. DIPL.-ING. GERHARD COLDEWEY

PATENT LAWYERS. Ί * 7 * 7 * 7 Π G

.β MUNICH 23 · S IEG ESSTRASSE 26. TELEPHONE 346087. TELEQRAMU-AOHESSE: INVENT / MDNCHEN

uZ: D 479 (Cy / eb) _{5 #} September 1968

+ a

PROLIZENZ AG., - -

Chur, Switzerland

Device for stretching metal cups to form can bodies

Priority: September 7, 1967, Switzerland, Mr. 12 504/67

The present invention relates to a Device for stretching metal cups to form can bodies.

Can bodies made from tinplate are usually made by rolling tinplate tape into a hollow cylinder, soldering the abutting longitudinal edges and subsequent seaming of a floor. However, B's are already procedures in testing, after which the. Can bodies manufactured seamlessly using the so-called roll-bond process will; however, the floor must be seamed separately.

In the field of can production, aluminum and its alloys occupy an ever wider seam, since the cans made from them have significant advantages over those made from tinplate; light weight, no risk of rust, versatile possibilities of opening without the use of a special tool, etc .. A particularly big advantage of the light metal cans is that their body and base can be produced in one piece and seamlessly by extrusion or deep drawing? The cover only needs to be applied in a suitable manner, for example by folding using a sealing intermediate layer, by gluing, etc., ¹ 109815/0880

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Generally used for the manufacture of light metal can bodies Pure aluminum sheet used. The can bodies made from it have in most cases a Wall thickness from 0.2 to 0.5 mm; a greater wall thickness is required for aerosol cans, e.g. 0.8 mm.

In competition with the tinplate cans, it would be necessary in some cases to achieve an equal dent resistance Aluminum sheet of so great thickness can be used that the aluminum can with the tinplate can is not priced could compete more.

Its higher dent resistance could be achieved by using an aluminum alloy instead of pure aluminum, because the alloy has a higher mechanical strength. Then a thinner wall thickness could be selected, which would have a favorable effect on the purchase price of the can and would make it competitive again. For this purpose, aluminum alloys of the types ABIg ₂ , AlMg ₅ , AlMn with 1.5 # Mn and AlMnMg with 1 ^ Mn and 1 fo Mg are particularly suitable. In the cold-worked state, these alloys have a tensile strength that significantly exceeds that of cold-worked pure aluminum. The alloys mentioned are low-alloy aluminum, which, in contrast to alloys of the types AlMgSi, AlCuMg and AlZnMg, can only be hardened by cold working, but not by heat treatment (solution annealing, quenching and cold or hot hardening); the production of can bodies from such alloys warmaushärtbaren is quite possible dooh required with them heat treatment means a complication and price increase \ fabrication.

In a known deep-drawing process for thin-walled aluminum cans, two different operations are carried out one after the other, namely the deformation of a round blank by deep drawing and then immediately afterwards and the same Maeohine

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the stretching of the V / and of the drawn head by a Series of lubricated pull rings through it. With this method, a maximum of 50 to approx. Make 100 can bodies from pure aluminum. The process has so far been used in the manufacture of can bodies from aluminum! greed did not produce satisfactory results.

The difficulties that arise in the latter process are mainly due to the friction and heat generation occurring in the drawing rings; After a number of ironing operations, heat builds up and the lubricating film tears off. In addition, the process is extremely sensitive to small fluctuations in the quality of the bonds, for example in the thickness of the circular blank. the grain size of the sheet and its texture. Finally, the process mentioned can only be used for processing pure aluminum, quite apart from the fact that in the production of cans from low-alloy aluminum, e.g. made of AlMg ₂ or AlMg ,, the intention is to further reduce the wall of the finished can, which, as stated at the beginning, is necessary for price reasons.

Unfortunately, it has been shown that the production of one-piece, seamless can bodies from low-alloy aluminum of the types in question (AlMg- etc.) cannot be produced perfectly using the drawing process that is most commonly used.

If the wall thickness is reduced by pulling through one or more pull rings, brittleness occurs as a result of excessive cold deformation and the wall of the can body - * tears. Theoretically, the brittleness could be avoided by one CD or several intermediate anneals, but one does

Such a cumbersome process is practically out of the question, and neither is hot drawing.
ο

σ> The device according to the invention is characterized by a plurality of drawing roller calibres, by a drawing die known per se, and by channels , the outlet of which is opening

is directed against the deformation surface of the lumps and the. are connected to a lubricant pressure tank; preferably comes another essential feature added, namely the vertical arrangement of the device, with the free end face of the drawing punch facing up is directed.

Kit using this device eliminates the difficulty of making the can body from aluminum alloys overcome in that the drawing process is replaced by a rolling process in which the tool surfaces, which reduce the wall thickness, move in the same direction as the can wall to be drawn, so that none significant mutual displacement takes place between the can wall and the mold surface. If necessary, will the rolling process is supplemented by a drawing process (using draw rings).

There are bowls made of metal, e.g. aluminum and preferably aluminum alloys, with the help of several Drawing pin calibers and a drawing die stretched to form can bodies, whereby a diluted lubricant, preferably an oil-in-water emulsion, sprayed against the drawing rollers in such a way that it is diluted Lubricants not only the deformation surface of the rollers and the outer surface of the hollow body to be stretched as well the bearings of the rollers lubricates, but also has a cooling effect and abrasion and other impurities washes away.

2 to 10 $ oil-in-water emulsions have proven to be proved beneficial. According to a preferred embodiment, the jet of lubricant against the rollers is like this directed that these are set in rotation, in the sense of rotation, which is the direction of movement of the can body when stretching corresponds; this is achieved by the off-center impact of the lubricant jet on the Roles achieved. 109815/08

1777009

Ss is known, the wall thickness of relatively thick-walled Reduce pipes with the help of one or more pulling roller gauges. The German patent specification shows No. 890 937 a drawing roller head for cold drawing of tubes, the three or preferably four forming a caliber Has drawing rollers of small diameter, which are based on a corresponding number of support rollers of larger diameter prop up. The German Auslegeschrift Kr. 1 040 describes a similar tool in which the calibers from 5 to 7, which perform the essential stretching work, are preferably but are made up of 6 roles. According to the American patent specification No. 2,361,318 a seamless Steel pipe is stretched by a roller drawing caliber until it has a wall thickness, e.g. with an outer diameter of 290 mm of 13 mm; the ratio of the wall thickness to the outer diameter is thus around 4.5 ^ - The number of rollers is 8 per caliber and it can be 1 to 10 or more Caliber can be used, but preferably 2 or 3.

From the outset it seemed very doubtful whether it would be possible to make extremely thin-walled, cylindrical bowls Stretching out cans by means of a roller caliber, a process that so far has only been used to stretch out cans that are sometimes very thick-walled Pipes was applied.

The difference between iron and steel pipes, which are used as water pipes and the like, on the one hand, and Packaging cans, on the other hand, is in terms of wall thickness extraordinarily large, which is evident from the fact that the wall thickness of a packaging can is well within the thickness tolerance for the wall of steel pipes is. ._ * Pure cans with a diameter of, for example, 50 to ^ 120 ram made of Aliunini alloy has a wall thickness of about 0.15 to 0.3 mm in embossing; the ratio of the wall thickness σι to the outside diameter is thus about $ 0.3 to $ 0.25.

In addition, the working speed at the Bosenherstelluag exceeds that of pipe stretching by means of an Ecilenkallbera many times over. When stretching cans, the 4-way punch must move back and forth approximately 1 to 5

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perform per second. The operating speed of the The punch is therefore about 100 to 500 m / min, with too

themselves
take into account that / the direction of movement during

this time changes 120 to 600 times.

Another very important difference between stretching pipes and stretching can bodies consists in the fact that the tubes are open at both ends, while the can bodies, which are stretched from cells, have a bottom and as a result are only open at one end. 3s will be highlighted below which great importance to this. Difference is due.

With the device according to the invention can not only Bowls made of aluminum alloys and of course also made of pure aluminum, but also those made of other deformable ones Metals, including steel, 2 to 4 times as much as cans with a diameter of 50 to 100 mm, for example and stretch to a length of 100 to 350 mm, for example.

The invention was based on the object, especially Büumpf for Beer cans (length 140 mm), food cans (length 120 mm) and. Aerosol cans (length currently up to 340 mm) made of aluminum alloys to create.

When carrying out the method according to the invention "the initial wall thickness of the cylindrical part is at most 3 # of the inner diameter of the hollow body ; it is preferably 1.5 and less.

The devices for feeding the cells and for wiping off the stretched can bodies by means of compressed air or another pressurized gas or also mechanically belong to the state of the art? likewise the counter-stack, with which the device is preferably equipped and which primarily serves to give the bottom of the can body the desired orientation

bring su,

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or to be provided with an embossing or a protruding pin.

In contrast to the well-known stretching of relatively thick-walled In the device according to the invention, pipes is, if it has a counter punch, the diameter of the rollers in relation to the wall thickness of the hollow body of great importance, since the can bodies have a bottom that during the stretching process or, better, deformed after it has been completed, e.g. is arched or embossed, namely in the device itself during or after the pulling. Of the The bottom of the can body must therefore remain in contact with the face of the drawing punch, since this is together with the counter punch must serve as a deformation or embossing tool. The can body and its bottom must not lead when stretching do not become detached from the face of the drawing punch, as otherwise the desired deformation or embossing will not take place and the soil would be crushed as a result of the cavity. When stretching steel pipes and Such a problem does not arise in any way and any leading of the hollow body does not interfere.

will grfTtttiHHgsggaäagxjgxrjd Bas advance / through correct choice of Avoided diameter of the rollers in relation to the wall thickness of the hollow body. The diameter of the rollers must not be less than 50 times the end wall thickness of the can body and not greater than 300 times; it is preferably 100 to 250 times the rolled wall thickness. For example, can bodies are made from Aluminum alloy with a wall thickness of 0.15 to 0.3 mm (with a can diameter of 50 to 120 mm, for example) expediently Rolls with a diameter of 15 to 80 mm are used. The diameter of the rollers is the same as the diameter of the Can body independent. For wall thicknesses of 0.2 to 0.5 mm, it is preferably 45 to 50 mmj for a wall thickness of 0.8 mm, for example, could also be used with a roll diameter of

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60 mm are sufficient, but the decrease in thickness would have to be selected to be smaller for each caliber. Excessive rolling down causes excessive burr formation. On the basis of the above findings, the device for carrying out the method according to the invention must be constructed in such a way that the diameter of the rollers is 50 to 300 times, preferably 100 to 250 times the smallest distance on all sides of the roller circumference (ie the deformation surface of the Rollers) from the surface of the die.

It is advantageous to reduce the roll diameter from roll caliber to roll caliber in the pulling direction.

When reducing the wall thickness of a cylindrical hollow body, ribs are created between the individual rollers in the drawing direction of the drawing tool. This fact alone requires the use of in the production of smooth-walled hollow bodies at least two roller gauges (roller assemblies), the rollers of which are offset from one another in such a way that they pass through the ribs that were created by the first are made to disappear by the second roller caliber. Of course you have to ensure that the distance between two laterally adjacent work rolls is as small as possible is so that the resulting ribs are as narrow as possible. This distance should in the device according to the invention be less than 0.3 mm, preferably 0.2 mm or less.

In general, the wall thickness is not reduced as much as is desired when passing through the first roller caliber is. As a result, the second roller cage not only has to make the ribs created by the first disappear, but reduce the strength of the rest of the wall, whereby ribs arise again. In this case, a third reel caliber is required, which in turn usually does the job has to both press ribs smoothly, as well as to further reduce the wall. The number of reel calibers can be 4

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exceed and reach e.g. 10. After all, it is useful to choose them only as large as absolutely necessary, since the difficulties of the construction due to oversized The punch stroke naturally increases with the number of roller calibers, especially because the one carrying the punch Stamp rod would have to be too long; the stamp that takes care of the pulling must namely the cup to be pulled at the entrance of the drawing tool and protrude at the other end of the drawing tool so far that the drawn hollow body can be removed without difficulty. For the production of beer cans of around 140 mm length and 65 mm The diameter of the punch stroke must be around 650 mm, for example.

To achieve the last smoothing of the can before leaving the drawing tool, it is useful, but not essential, to arrange one or more normal pull rings with a polished working surface instead of a roller caliber.

It can be useful to arrange these pull rings in a self-centering manner.

In-depth tests have shown that when stretching can bodies, each roll caliber at least 10 rolls on «- Must have, preferably 12 or more. In general, with the same precision of the surface of the rollers and at Select the same material of the hollow body, the greater the number of rollers, the smaller the wall thickness in relation to on the hollow body diameter. E.g. a roller caliber for the production of cans with a wall thickness of 0.2 mm and 65 mm diameter made of an aluminum-magnesium alloy with about 2% Mg, advantageously according to the invention 12 up to 18 rolls.

If you look at the very thin wall thickness of the finished can bowl (e.g. 0.2 to 0.3 mm), you can see without

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_1Λ ■ 17770C9

further that extremely high demands must be made on the precision of the leadership of the stamp, which with those of the punch guide when stretching from proportionately thick-walled pipes, e.g. made of iron or steel, cannot be compared.

The known machines with pulling roller gauges for stretching pipes are arranged horizontally. They are too most devices for pulling can bodies, too the newest. The experiments that lead to the formation of the inventive Can stretching device led, but have shown that for this preferably the vertical or almost vertical Arrangement of the pulling device comes into question, otherwise the long punch rod due to its own weight the inclination has to bend against the lower pulling rollers. Although such bending can be kept extremely small can, the difference in thickness caused by this phenomenon in the cross-section of the wall due to the very small Strength of the same do matter. The same applies. for an inclined installation of the machine.

In the case of a vertical or inclined installation, the can stretching device now either arranged in such a way that the punch pushes the bowl through the drawing caliber from top to bottom presses and the can body leaves the tool below, or but in such a way that the punch presses the hollow body upwards from below. The latter arrangement is because of the inventive Lubrication is by far the most beneficial.

In-depth investigations have shown that a sliding bearing of the rollers in the device according to the invention is not useful. Only roller bearings come into question, in view of the very limited space available, preferably needle roller bearings.

The rolls in each roll caliber do not necessarily have to be of the same width. The caliber can vary

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can be equipped with narrow and wide roles.

The outlet diameter of the lubricant channels, which are directed towards the circumference of the rollers, must be so narrow that under the applied pressure, the diluted lubricant hits in a sharp jet. With one under one pressure for example from 2 to 5 atm. oil-in-water emulsion and with a lubricant channel outlet diameter of approx. 1 mm, the speed of the lubricant jet can be about 15 to 20 m / s.

If the lubricant jets are otherwise freely rotating If the rollers hit eccentrically, they receive an additional drive, which significantly increases the number of strokes enables.

The type of lubrication according to the invention is also preferable inventive arrangement of the can stretching device guided.

In the case of a horizontal or inclined position of the machine, the one-sided drainage of the diluted lubricant would mainly affect thereby having a disruptive effect that impurities are temporarily in the storage of the underlying rollers of the various Caliber would penetrate and disrupt operations; the high working speed of the machine and the very thin Wall thickness of the can body could not allow such disturbances. This problem does not arise with the known either Stretching out pipes using a pulling roller. In the method according to the invention, however, there is the risk of malfunction mentioned here Another reason for the preferred choice of the vertical arrangement of the device.

In addition, the inventive type of Lubrication that by far the most advantageous arrangement of the machine is that in which the vertically operated

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The punch presses the hollow body from bottom to top. The lubricant flow namely is collected at the bottom, filtered and put back into circulation. If the doe hulls would emerge below, where would they pick up some of the draining lubricant, as they would have to be stripped bottom down; that would seriously disturb the lubricant circulation not to mention the much more difficult removal of the stretched can bodies.

In the device according to the invention, the stripping takes place the can body in a known manner by compressed air which is fed to the drawing punch through a longitudinal bore, or in a mechanical way; then the can bodies are expediently and also according to a known method blown away by a side jet of air "

The drawing illustrates schematically the mode of operation in FIGS. 1 and 2 and represents in FIGS. 3 and 4 shows a particularly advantageous embodiment of the characteristic parts of the device according to the invention. FIG shows a section through the initial cup and FIG. 2 shows the stretching of the cup to form a can body. Fig. 3 represents shows a view of the device largely in section, FIG. 4 shows a cross section along the line A-A of FIG.

The cup 10 according to FIG. 1 is made by deep drawing or produced by any other means. According to the invention, it is carried out by means of a drawing punch 11 (FIG. 2) one or more drawing calibers 12 pushed, with its wall being stretched and thinner; the one shown schematically The drawing caliber consists essentially of a ring of rollers 13 and bearing journals. 14.

The device according to FIG. 3 comprises four arranged one above the other in a housing 15 which rests on a base 16 Pulling roller caliber 17. The caliber 17 is each provided with a ring of twelve deforming rollers 18, which are placed on needle

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bearing 19 rotate. The holders 20 lie against the cylinder wall 2 fed up. The distance between the peripheral surface of the rollers 18, i.e. the distance of its deformation surface from the punch 22 is for the lower reel caliber, for example, 0.45 mm. This distance • decreases from caliber to caliber and amounts to upper pulling roller caliber, for example, only 0.25 mm. The wall thickness of the cell is here, for example 0.6 mm reduced to 0.25 mm.

The ring lines 23 serve to supply the lubricant to the bores 24, which act as lubricant channels. At the free end of the lubricant channels, nozzles 25 are attached, ^ which are directed eccentrically against the rollers 18, so that when the lubricant is sprayed on, not only the deformation surface of the rollers, the outer surface of the hollow body to be stretched and the bearings 19 of the rollers lubricated, exerted a cooling effect and abrasion and other impurities washed away, but also the rollers 18 are set in rotation, in such a way that their deformation surface on the side facing the drawing die 22 is moved upwards

In order to achieve the final smoothing of the outer wall of the can, two pulling rings 26 and 27 are shrunk into chucks 28 and 29, respectively, over the pulling roller calibers. The intermediate ring 30 M.

is not absolutely necessary; it permits subsequent installation of another pull roll caliber or another drawing ring, The expanded space 31 at the inner, lower part of the lubrication channel ring 32 serves for collecting the lubricating fluid and the bores is injected 34 against the can surface through the annular channel 33; the collected lubricating fluid flows through the annular recess 35 and the bores 36 into the interior of the pulling device.

The stamp 22 is screwed into the upper end face of the stamp rod 37 , which is actuated by a drive, not shown, located below. It has an indentation 38 which, in cooperation with the lower end face

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ORIGINAL fNSPECTED

page 39 of the counter punch 40 gives the bottom of the can body the desired arched shape.

The counter stack 40 is driven here in a known manner. 41 is a hold-down device elastically mounted on a helical spring 42. The pressure when the ends 38 and 39 deforms the bottom of the can body in the desired manner.

The side compressed air supply to blow away the can body after it has been stripped from the drawing punch 22 is not shown. It is known per se, as is the drive of the Drawing punch rod, which generally belongs to the state of the art. A special graphic representation is therefore superfluous.

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ORIGINAL INSPECTED

Claims (12)

17770C9 - 15 - Expectations ί 1.) Process for stretching metal bowls to form can bodies, characterized in that the stretching with the aid of several drawing roller gauges and a drawing punch happens, whereby a diluted lubricant is sprayed against the pulling rollers in such a way that that it does not, only the deformation surface of the rollers and the outer surface of the hollow body to be stretched as well the bearings of the rollers lubricates, but also has a cooling effect and abrasion and other impurities washes away. 2. The method according to claim 1, characterized in that the lubricant jets against the rollers are directed so that they are set in rotation in the direction of rotation, which is the direction of movement of the can body when stretching. 3. The method according to claim 1 and 2, characterized in that that the lubricant is an oil-in-water emulsion. 4. Machine for performing the method according to claim 1, characterized in that the same has at least two drawing roller calibers (17), a drawing punch (22) as well as channels (24), the outlet opening (25) of which is directed against the deformation surface of the rollers and which are to be connected to a lubricant pressure tank. 5. Machine according to claim 4, characterized in that that the rollers (18) are rotatably arranged in roller bearings. 1 0 9 8 1 B / 0 8 6 pcs 17770G-9 6. Machine according to claim 5, characterized in that the rollers (18) are rotatably arranged in needle bearings (19) are. 7. Machine according to claim 5 or 6, characterized in that the diameter of the rollers (18) is the 50th "up to 300 times the smallest distance on all sides of the Roll circumference from the surface of the drawing punch (22). 8. Machine according to claim 7, characterized in that the diameter of the rollers (18) 100 to 250 times the smallest distance on all sides of the roller circumference from the surface of the drawing punch (22). 9. Machine according to claims 4-8, characterized in that each drawing roller caliber (17) at least ten Has roles (18). 10. Machine according to claim 9, characterized in that; each drawing roll caliber twelve to eighteen rolls (18) has. 11. Machine according to claim 4, characterized in that the outlet openings (25) of the channels (24) so directed are that in operation the lubricant jets on the deformation surface of the rollers (18) in such Way off-center that this hit in the direction of rotation be set in rotation, which corresponds to the direction of movement of the can body during stretching. 12. Machine according to claims 4-11, characterized by at least one drawing ring (26/27) through which the can body is hit at the end of the deformation. 13 · Machine according to claims 4-12, characterized in that that it is set up vertically. 1 0 9 8 1 5 / Π 8 6 ^r 0 17770C9 14-. lias chine according to claim 13, characterized that the end face (38) of the drawing stack (22) is directed upwards. 10 9 8 15