EP0167855B1 - Tearable box body - Google Patents

Tearable box body Download PDF

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Publication number
EP0167855B1
EP0167855B1 EP85107150A EP85107150A EP0167855B1 EP 0167855 B1 EP0167855 B1 EP 0167855B1 EP 85107150 A EP85107150 A EP 85107150A EP 85107150 A EP85107150 A EP 85107150A EP 0167855 B1 EP0167855 B1 EP 0167855B1
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EP
European Patent Office
Prior art keywords
longitudinal edge
welded
outer longitudinal
sheet
metal blank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP85107150A
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German (de)
French (fr)
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EP0167855A3 (en
EP0167855A2 (en
Inventor
Paul Opprecht
Werner Urech
Jürg Opprecht
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Elpatronic AG
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Elpatronic AG
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Publication date
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Priority to AT85107150T priority Critical patent/ATE52477T1/en
Publication of EP0167855A2 publication Critical patent/EP0167855A2/en
Publication of EP0167855A3 publication Critical patent/EP0167855A3/en
Application granted granted Critical
Publication of EP0167855B1 publication Critical patent/EP0167855B1/en
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D17/00Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions
    • B65D17/42Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions with cutting, punching, or cutter accommodating means
    • B65D17/46Wires, strings or the like, e.g. rip cords
    • B65D17/462Tearing-strips or -wires
    • B65D17/464Tearing-strips or -wires with tongues or tags for engagement by slotted keys

Definitions

  • the tab is stamped out in one piece together with the sheet metal blank which is flat in the initial state and extends in its plane beyond the edge of the outer longitudinal edge.
  • a starting scoring is stamped into the sheet metal blank in the area of the inner longitudinal edge.
  • the sheet metal blank is rolled into a cylinder before its two longitudinal edges are welded, so that the two longitudinal edges overlap one another.
  • the starting score of the inner longitudinal edge comes to lie under the outer longitudinal edge.
  • the starting score is, for example, a straight line that extends parallel to the edge of the inner longitudinal edge; in this case it coincides with the edge of the outer longitudinal edge after the cylinder has rolled.
  • the starting score can also have the shape of a triangle or segment of a circle, the base of which forms the edge of the inner longitudinal edge.
  • Such can bodies with welded longitudinal seams and protruding, integrally formed flaps have long been widespread and are gradually replacing the can bodies with folded and then soldered longitudinal seams, which have been known for a considerably long time and also have a flap punched out in one piece with the sheet metal blank of the can body.
  • tear strip With all of these known can bodies, especially inexperienced users, it is not always possible to completely remove the tear strip in the desired manner. It is not uncommon for the tear strip to tear off in the area of the longitudinal seam or shortly behind it, because converging tear lines form from the flap and meet in the middle between the two circumferential scratches. The user is then forced to continue opening the can with a tool that is not intended for this purpose, with the risk that he will injure himself on the sharp sheet metal edges that arise.
  • the invention is therefore based on the object of developing a can body of the type described at the outset in such a way that it can be torn open with greater certainty.
  • the object is achieved according to the invention in that the flap is welded onto the outer longitudinal edge as a separate sheet metal part and in that the starting score is at a distance from the outer longitudinal edge which is three to seven times, preferably five times as large as the thickness of the sheet metal blank.
  • the flap with the outer longitudinal edge is welded to 85 to 95% of the width of the tear strip.
  • the tear strip is stiffened practically over its entire width in the area of the longitudinal seam, so that the circumferential scratches are essentially only loaded with shear forces and practically not with tensile forces when rolled up will.
  • This type of stress is particularly conducive to tearing open along the circumferential scratches.
  • the limitation of the width of the welding zone when welding the flap to 95% of the width of the tear strip guarantees that the circumferential scratches lie outside the welding zone.
  • Another measure that helps to cause cracks to appear along the circumferential scratches when the welded-on tab is rolled up is that the outer longitudinal edge has a notch at the beginning of the circumferential scratches.
  • the flap has a prefabricated profile formed by sharp-edged longitudinal ribs at least in the welding zone which connects it to the outer longitudinal edge.
  • the profiling helps the tab to be firmly connected to the outer longitudinal edge when it is welded on.
  • the longitudinal edges are welded in advance, it is in fact not possible, or can only be avoided by special precautions, that an oxide layer forms, which makes it more difficult to weld the tab. This difficulty is overcome by the profiling provided on the tab, which penetrates its oxide layer when the tab is pressed against the outer longitudinal edge.
  • the tab is made of sheet metal of higher strength than the sheet metal blank, the above-mentioned stiffening effect can be optimal when the tab is rolled up, without the roll-up being noticeably more difficult.
  • a can body 10 which, for example, consists of tinplate with a thickness a of 0.2 mm.
  • the can body 10 has an outer longitudinal edge 12 and an inner longitudinal edge 14 and a pair of circumferential scratches 16 which extend at right angles to these longitudinal edges and delimit a tear strip 18 between them.
  • the can body 10 also includes an elongated rectangular tab 20, which is made, for example, of tinplate with a thickness b of 0.4 mm and extends the tear strip 18 beyond the outer longitudinal edge 12.
  • the can body 10 which here has an essentially rectangular cross section, is opened with a key 22.
  • the key 22 has been placed on the tab 20 and is unrolled on one of two flanged edges 24 which connect the can body 10 to a lid or bottom 26.
  • the can body 10 is made from a sheet metal blank 28 originally planar as shown in FIGS. 3 and 4, which is initially rolled into a cylinder regardless of the cross-sectional shape of the finished can, as indicated in FIG. 1 by a circle.
  • the two circumferential scratches 16 and a starting scratch 30 are stamped into the still flat sheet metal blank 28.
  • the two circumferential scratches 16 extend from the edge 32 of the outer longitudinal edge 20 to the edge 34 of the inner longitudinal edge 14.
  • the starting scratch 30 extends parallel to the edge 34 and delimits a rectangle 36 with this and the adjacent sections of the circumferential scratches 16.
  • the width of this Rectangle ie the distance c of the starting score 30 from the edge 34, is preferably 1.0 mm if the two longitudinal edges 12 and 14 are to be welded to one another in such a way that they overlap over a width of 0.4 mm, as is the case with a sheet thickness of 0.2 mm is common.
  • the starting scoring 30 extends beyond each of the two circumferential scoring 16 by a distance d that is approximately 0.5 mm long and thus is approximately 2.5 times the sheet thickness a.
  • the tab 20 is as wide as the distance between the two circumferential scratches 16 and is connected to it according to FIG. 2 in a welding zone 42 which extends over approximately 90% of the space between the two circumferential scratches 16.
  • the tab 20 is provided with a prefabricated, i.e. provided before the welding on, which is formed according to FIG. 3 by sharp-edged longitudinal ribs 43 and is pressed more or less flat when welding.
  • FIG. 4 The details shown in FIG. 4 have been modified compared to FIG. 3 in that the outer longitudinal edge 12 has a notch 44 at the beginning of each of the two circumferential scratches 16 and a crescent-shaped recess 46 between these notches.
  • a pair of warts 48 are formed on the tab 20 as profiling, each of which is relatively closely adjacent to one of the longitudinal edges of the tab and ensures that the tab is welded to the start of the tear strip 18 in the immediate vicinity of its longitudinal edges.
  • a device with a fixed arm 50, on which an inner electrode roller 52 is mounted, the lateral surface 54 of which is only somewhat suitable, is suitable for welding the can body 10 is wider than 0.4 mm, the overlap width of the two longitudinal edges 12 and 14.
  • the inner electrode roller 52 is opposed by an outer electrode roller 56 with a correspondingly narrow lateral surface 58, which is mounted on a plunger 60 which can be moved radially to the arm 50.
  • the sheet metal blank 28 is rolled around the arm 50 in a conventional manner and passed between the two electrode rollers 52 and 56, the weld seam 40 being formed in the form of an overlapped crimped seam between the two longitudinal edges 12 and 14.
  • a stationary inner electrode 62 Arranged on the arm 50 in the direction of movement of the resulting can body 10 behind the inner electrode roller 52 is a stationary inner electrode 62 which has a cylindrical current transfer surface 64 corresponding to the radius of curvature of the can body 10. This inner one. Electrode 62 is opposed to an outer electrode 66, which has a cutting-shaped current transfer surface 68 and can be cyclically moved back and forth to the can body 10.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rigid Containers With Two Or More Constituent Elements (AREA)

Description

Die Erfindung betrifft einen aufreissbaren Dosenrumpf aus einem Blechzuschnitt mit

  • einem äusseren und einem inneren Längsrand, die überlappend miteinander verschweisst sind,
  • mindestens einem Paar Umfangsritzungen, die sich quer zu den Längsrändern um den Dosenrumpf herum erstrecken und einen Aufreissstreifen seitlich begrenzen,
  • einer Startritzung zwischen den Umfangsritzungen im Bereich des inneren Längsrandes, und
  • einer Lasche, die den Aufreissstreifen über den äusseren Längsrand hinaus verlängert.
The invention relates to a tear-open can body made from a sheet metal blank
  • an outer and an inner longitudinal edge, which are welded to overlap,
  • at least one pair of circumferential scratches which extend transversely to the longitudinal edges around the can body and laterally delimit a tear strip,
  • a start scratch between the circumferential scratches in the area of the inner longitudinal edge, and
  • a tab that extends the tear strip beyond the outer longitudinal edge.

Bei einem bekannten Dosenrumpf dieser Gattung (DE-B 017 042) ist die Lasche zusammen mit dem im Ausgangszustand ebenen Blechzuschnitt in einem Stück ausgestanzt und erstreckt sich in dessen Ebene über die Kante des äusseren Längsrandes hinaus. Zwischen den Umfangsritzungen ist eine Startritzung im Bereich des inneren Längsrandes in den Blechzuschnitt eingestanzt. Der Blechzuschnitt wird vor dem Verschweissen seiner beiden Längsränder zu einem Zylinder gerollt, so dass die beiden Längsränder einander überlappen. Dabei kommt die Startritzung des inneren Längsrandes unter den äusseren Längsrand zu liegen. Die Startritzung ist beispielsweise eine Gerade, die sich parallel zur Kante des inneren Längsrandes erstreckt; in diesem Fall deckt sie sich nach dem Rollen des Zylinders mit der Kante des äusseren Längsrandes. Die Startritzung kann aber auch die Form eines Dreiecks oder Kreissegments haben, dessen Basis die Kante des inneren Längsrandes bildet. Aus einem solchen Dosenrumpf entsteht nach dem Verschweissen seiner Längsränder eine vollständige Dose, indem die beiden Stirnseiten des Dosenrumpfes durch Bördeln mit einem Deckel bzw. einem Boden verschlossen werden. Zum Aufreissen der Dose wird auf die Lasche ein Schlüssel aufgesteckt, der zu diesem Zweck einen Schlitz aufweist und am nächstgelegenen Bördelrand abgerollt wird.In a known can body of this type (DE-B 017 042), the tab is stamped out in one piece together with the sheet metal blank which is flat in the initial state and extends in its plane beyond the edge of the outer longitudinal edge. Between the circumferential scoring, a starting scoring is stamped into the sheet metal blank in the area of the inner longitudinal edge. The sheet metal blank is rolled into a cylinder before its two longitudinal edges are welded, so that the two longitudinal edges overlap one another. The starting score of the inner longitudinal edge comes to lie under the outer longitudinal edge. The starting score is, for example, a straight line that extends parallel to the edge of the inner longitudinal edge; in this case it coincides with the edge of the outer longitudinal edge after the cylinder has rolled. The starting score can also have the shape of a triangle or segment of a circle, the base of which forms the edge of the inner longitudinal edge. After the longitudinal edges have been welded together, such a can body becomes a complete can in that the two end faces of the can body are closed by flanging with a lid or a base. To tear open the can, a key is placed on the tab, which has a slot for this purpose and is unrolled at the closest flange edge.

Solche Dosenrümpfe mit geschweisster Längsnaht und über diese hinausragender, einstückig angeformter Lasche sind seit langem weit verbreitet und verdrängen allmählich die seit noch erheblich längerer Zeit bekannten Dosenrümpfe mit gefalzter und anschliessend verlöteter Längsnaht, die ebenfalls eine mit dem Blechzuschnitt des Dosenrumpfes einstückig ausgestanzte Lasche aufweisen. Bei all diesen bekannten Dosenrümpfen gelingt es vor allem ungeübten Benutzern nicht immer, den Aufreissstreifen in der gewünschten Weise vollständig zu entfernen. Nicht selten reisst der Aufreissstreifen schon im Bereich der Längsnaht oder kurz dahinter ab, weil sich von der Lasche ausgehend konvergierende Risslinien bilden, die sich in der Mitte zwischen den beiden Umfangsritzungen treffen. Der Benutzer ist dann gezwungen, das Oeffnen der Dose mit einem für diesen Zweck nicht vorgesehenen Werkzeug fortzusetzen, wobei die Gefahr besteht, dass er sich an den entstehenden scharfen Blechrändern verletzt.Such can bodies with welded longitudinal seams and protruding, integrally formed flaps have long been widespread and are gradually replacing the can bodies with folded and then soldered longitudinal seams, which have been known for a considerably long time and also have a flap punched out in one piece with the sheet metal blank of the can body. With all of these known can bodies, especially inexperienced users, it is not always possible to completely remove the tear strip in the desired manner. It is not uncommon for the tear strip to tear off in the area of the longitudinal seam or shortly behind it, because converging tear lines form from the flap and meet in the middle between the two circumferential scratches. The user is then forced to continue opening the can with a tool that is not intended for this purpose, with the risk that he will injure himself on the sharp sheet metal edges that arise.

Der Erfindung liegt deshalb die Aufgabe zugrunde, einen Dosenrumpf der eingangs beschriebenen Gattung derart weiterzubilden, dass er sich mit grösserer Sicherheit aufreissen lässt.The invention is therefore based on the object of developing a can body of the type described at the outset in such a way that it can be torn open with greater certainty.

Die Aufgabe ist erfindungsgemäss dadurch gelöst, dass die Lasche als gesondertes Blechteil an den äusseren Längsrand angeschweisst ist und dass die Startritzung vom äusseren Längsrand einen Abstand hat, der drei- bis siebenmal, vorzugsweise fünfmal so gross ist wie die Dicke des Blechzuschnitts.The object is achieved according to the invention in that the flap is welded onto the outer longitudinal edge as a separate sheet metal part and in that the starting score is at a distance from the outer longitudinal edge which is three to seven times, preferably five times as large as the thickness of the sheet metal blank.

Es hat sich überraschenderweise erwiesen, dass durch das Anschweissen einer gesondert hergestellten Lasche bessere Voraussetzungen für einen einwandfreien Aufreissvorgang geschaffen werden als durch einstückige Ausbildung von Lasche und Blechzuschnitt. Durch das Anschweissen der Lasche entsteht im Bereich der Längsnaht zwischen den beiden Umfangsritzungen eine zusätzliche Versteifung, die wesentlich dazu beiträgt, dass die beim Aufrollen der Lasche entstehenden Risslinien den Umfangsritzungen folgen. Sodann wird durch das Einhalten des vorgesehenen Abstandes der Startritzung vom äusseren Längsrand mit Sicherheit ausgeschlossen, dass die Startritzung beim Anschweissen der Lasche in die Schweisszone gerät und dadurch unwirksam wird. Es ist also gewährleistet, dass das Anreissen mittels der Lasche gelingt und dass anschliessend der Aufreissstreifen vollständig und einwandfrei aufgerollt werden kann.Surprisingly, it has been found that welding a separately manufactured tab creates better conditions for a flawless tearing process than by forming the tab and sheet metal blank in one piece. When the flap is welded on, additional stiffening occurs in the area of the longitudinal seam between the two circumferential scratches, which contributes significantly to the fact that the tear lines that arise when the flap is rolled up follow the circumferential scratches. Then, by maintaining the intended distance of the starting score from the outer longitudinal edge, it is with certainty ruled out that the starting score gets into the welding zone when the tab is welded on and thus becomes ineffective. It is therefore guaranteed that the scribing is successful using the flap and that the tear strip can then be rolled up completely and properly.

Aus den Dokumenten US-A-2 753 075 und US-A-2 086 628 ist das Anschweissen einer Lasche als gesondertes Blechteil an einen Aufreissstreifen eines Dosenrumpfes an sich bekannt, jedoch nicht im Bereich von verschweissten Längsrändern und einer Startritzung in deren Bereich. Die Sicherheit gegen die Entstehung konvergierender Risslinien zwischen den beiden Umfangsritzungen lässt sich durch verschiedene weiterbildende Merkmale der Erfindung erhöhen. Dazu gehört, dass die Startritzung sich über die beiden zugehörigen Umfangsritzungen um eine Strecke hinauserstreckt, die zwei- bis dreimal so gross ist wie die Dicke des Blechzuschnitts. Damit wird erreicht, dass beim Aufrollen der angeschweissten Lasche die Startritzung über die beiden Umfangsritzungen hinaus aufbricht und anschliessend von den beiden Enden der Startritzung ausgehende Risslinien entstehen, von denen jede im Bereich der einander überlappenden und miteinander verschweissten Längsränder in die benachbarte Umfangsritzung einmündet und dadurch zusätzliche Gewähr dafür bietet, dass der Aufreissvorgang längs der Umfangsritzungen fortgesetzt wird.From the documents US-A-2 753 075 and US-A-2 086 628, the welding of a tab as a separate sheet metal part to a tear strip of a can body is known per se, but not in the area of welded longitudinal edges and a start scoring in their area. The security against the occurrence of converging crack lines between the two circumferential scratches can be increased by various further features of the invention. This includes that the starting score extends beyond the two associated circumferential scores by a distance that is two to three times the thickness of the sheet metal blank. The result of this is that when the welded-on tab is rolled up, the starting scoring breaks open beyond the two circumferential scoring and subsequently there are tear lines starting from the two ends of the starting scoring, each of which opens into the adjacent circumferential scoring in the region of the overlapping and welded longitudinal edges and thereby additional This is guaranteed by the fact that the tearing process is continued along the circumferential scratches.

Eine weitere Massnahme zur Vermeidung konvergierender Risslinien zwischen den Umfangsritzungen besteht darin, dass die Lasche mit dem äusseren Längsrand auf 85 bis 95% der Breite des Aufreissstreifens verschweisst ist. Durch eine solche Verschweissung wird der Aufreissstreifen im Bereich der Längsnaht praktisch auf seiner gesamten Breite versteift, so dass die Umfangsritzungen beim Aufrollen im wesentlichen nur mit Scherkräften und praktisch nicht mit Zugkräften belastet werden. Diese Art der Belastung ist einem Aufreissen entlang den Umfangsritzungen besonders förderlich. Zugleich bietet die Begrenzung der Breite der Schweisszone beim Aufschweissen der Lasche auf 95% der Breite des Aufreissstreifens Gewähr dafür, dass die Umfangsritzungen ausserhalb der Schweisszone liegen.Another measure to avoid converging tear lines between the circumferential scratches is that the flap with the outer longitudinal edge is welded to 85 to 95% of the width of the tear strip. By such a welding, the tear strip is stiffened practically over its entire width in the area of the longitudinal seam, so that the circumferential scratches are essentially only loaded with shear forces and practically not with tensile forces when rolled up will. This type of stress is particularly conducive to tearing open along the circumferential scratches. At the same time, the limitation of the width of the welding zone when welding the flap to 95% of the width of the tear strip guarantees that the circumferential scratches lie outside the welding zone.

Eine weitere Massnahme, die dazu beiträgt, beim Aufrollen der angeschweissten Lasche Risse entlang der Umfangsritzungen entstehen zu lassen, besteht darin, dass der äussere Längsrand am Anfang der Umfangsritzungen je eine Kerbe aufweist.Another measure that helps to cause cracks to appear along the circumferential scratches when the welded-on tab is rolled up is that the outer longitudinal edge has a notch at the beginning of the circumferential scratches.

Es ist ferner vorteilhaft, wenn die Lasche mindestens in der Schweisszone, welche sie mit dem äusseren Längsrand verbindet, eine vorgefertigte, durch scharfkantige Längsrippen gebildete Profilierung aufweist. Die Profilierung trägt dazu bei, dass die Lasche sich beim Anschweissen fest mit dem äusseren Längsrand verbindet. Beim vorangehenden Verschweissen der Längsränder ist es nämlich nicht oder nur durch besondere Vorkehrungen vermeidbar, dass sich eine Oxydschicht bildet, die das Anschweissen der Lasche erschwert. Diese Erschwernis wird durch die an der Lasche vorgesehene Profilierung überwunden, die beim Anpressen der Lasche an den äusseren Längsrand dessen Oxydschicht durchdringt.It is also advantageous if the flap has a prefabricated profile formed by sharp-edged longitudinal ribs at least in the welding zone which connects it to the outer longitudinal edge. The profiling helps the tab to be firmly connected to the outer longitudinal edge when it is welded on. When the longitudinal edges are welded in advance, it is in fact not possible, or can only be avoided by special precautions, that an oxide layer forms, which makes it more difficult to weld the tab. This difficulty is overcome by the profiling provided on the tab, which penetrates its oxide layer when the tab is pressed against the outer longitudinal edge.

Wenn die Lasche aus Blech höherer Festigkeit besteht als der Blechzuschnitt, kann die oben erwähnte Versteifungswirkung beim Aufrollen der Lasche ein Optimum erreichen, ohne dass das Aufrollen spürbar erschwert wird.If the tab is made of sheet metal of higher strength than the sheet metal blank, the above-mentioned stiffening effect can be optimal when the tab is rolled up, without the roll-up being noticeably more difficult.

Ausführungsbeispiele der Erfindung werden im folgenden anhand schematischer Zeichnungen mit weiteren Einzelheiten beschrieben.Exemplary embodiments of the invention are described below with the aid of schematic drawings with further details.

Es zeigt

  • Fig. 1 eine Konservendose mit einem erfindungsgemässen Dosenrumpf während des Oeffnens,
  • Fig. 2 einen vergrösserten Ausschnitt aus Fig. 1,
  • Fig. 3 Teile des Dosenrumpfes vor dem Verschweissen,
  • Fig. 4 Teile des Dosenrumpfes mit gegenüber Fig. 3 abgewandelten Einzelheiten und
  • Fig. 5 und 6 aufeinanderfolgende Schweissvorgänge am Dosenrumpf.
It shows
  • 1 is a can with a can body according to the invention during opening,
  • 2 shows an enlarged detail from FIG. 1,
  • 3 parts of the can body before welding,
  • Fig. 4 parts of the can body with compared to Fig. 3 modified details and
  • 5 and 6 successive welding operations on the can body.

In den Zeichnungen ist ein Dosenrumpf 10 dargestellt, der beispielsweise aus Weißblech mit einer Dicke a von 0,2 mm besteht. Der Dosenrumpf 10 hat einen äußeren Längsrand 12 und einen inneren Längsrand 14 sowie ein Paar Umfangsritzungen 16, die sich im rechten Winkel zu diesen Längsrändern erstrecken und zwischen sich einen Aufreißstreifen 18 begrenzen. Zum Dosenrumpf 10 gehört ferner eine langgestreckte rechteckige Lasche 20, die beispielsweise aus Weißblech mit einer Dicke b von 0,4 mm besteht und den Aufreißstreifen 18 über den äußeren Längsrand 12 hinaus verlängert.In the drawings, a can body 10 is shown which, for example, consists of tinplate with a thickness a of 0.2 mm. The can body 10 has an outer longitudinal edge 12 and an inner longitudinal edge 14 and a pair of circumferential scratches 16 which extend at right angles to these longitudinal edges and delimit a tear strip 18 between them. The can body 10 also includes an elongated rectangular tab 20, which is made, for example, of tinplate with a thickness b of 0.4 mm and extends the tear strip 18 beyond the outer longitudinal edge 12.

Gemäß Fig. 1 wird der Dosenrumpf 10, der hier einen im wesentlichen rechteckigen Querschnitt hat, mit einem Schlüssel 22 geöffnet. Der Schlüssel 22 ist auf die Lasche 20 aufgesteckt worden und wird auf einem von zwei Bördelrändern 24 abgerollt, die den Dosenrumpf 10 mit einem Deckel bzw. Boden 26 verbinden.1, the can body 10, which here has an essentially rectangular cross section, is opened with a key 22. The key 22 has been placed on the tab 20 and is unrolled on one of two flanged edges 24 which connect the can body 10 to a lid or bottom 26.

Der Dosenrumpf 10 ist aus einem gemäß Fig. 3 und 4 ursprünglich ebenen Blechzuschnitt 28 hergestellt, der unabhängig von der Querschnittsform der fertigen Konservendose zunächst zu einem Zylinder gerollt wird, wie in Fig. 1 mit einem Kreis angedeutet ist. In den noch ebenen Blechzuschnitt 28 werden die beiden Umfangsritzungen 16 sowie eine Startritzung 30 eingestanzt. Die beiden Umfangsritzungen 16 erstrecken sich von der Kante 32 des äußeren Längsrandes 20 bis zur Kante 34 des inneren Längsrandes 14. Die Startritzung 30 erstreckt sich parallel zur Kante 34 und begrenzt mit dieser und den angrenzenden Abschnitten der Umfangsritzungen 16 ein Rechteck 36. Die Breite dieses Rechtecks, also der Abstand c der Startritzung 30 von der Kante 34, beträgt vorzugsweise 1,0 mm, wenn die beiden Längsränder 12 und 14 derart miteinander verschweißt werden sollen, daß sie sich auf einer Breite von 0,4 mm überlappen, wie dies bei einer Blechdicke von 0,2 mm üblich ist.The can body 10 is made from a sheet metal blank 28 originally planar as shown in FIGS. 3 and 4, which is initially rolled into a cylinder regardless of the cross-sectional shape of the finished can, as indicated in FIG. 1 by a circle. The two circumferential scratches 16 and a starting scratch 30 are stamped into the still flat sheet metal blank 28. The two circumferential scratches 16 extend from the edge 32 of the outer longitudinal edge 20 to the edge 34 of the inner longitudinal edge 14. The starting scratch 30 extends parallel to the edge 34 and delimits a rectangle 36 with this and the adjacent sections of the circumferential scratches 16. The width of this Rectangle, ie the distance c of the starting score 30 from the edge 34, is preferably 1.0 mm if the two longitudinal edges 12 and 14 are to be welded to one another in such a way that they overlap over a width of 0.4 mm, as is the case with a sheet thickness of 0.2 mm is common.

Gemäß Fig. 2 und 3 erstreckt sich die Startritzung 30 über jede der beiden Umfangsritzungen 16 um eine Strecke d hinaus, die etwa 0,5 mm lang ist und somit etwa das 2,5-fache der Blechdicke a beträgt. Beim Aufrollen der Lasche 20 entstehen ausgehend von den beiden Enden der Startritzung 30 Rißlinien 38, von denen jede gemäß Fig. 2 allmählich in die benachbarte Umfangsritzung 16 einmündet; die Einmündung liegt im Bereich der Schweißnaht 40, welche die beiden Längsränder 12 und 14 miteinander verbindet. Von dieser Einmündung aus folgt der weitere Aufreißvorgang den beiden Umfangsritzungen 16, wie in Fig. 1 dargestellt.2 and 3, the starting scoring 30 extends beyond each of the two circumferential scoring 16 by a distance d that is approximately 0.5 mm long and thus is approximately 2.5 times the sheet thickness a. When the flap 20 is rolled up, 30 tear lines 38 arise from the two ends of the starting scoring, each of which gradually opens into the adjacent circumferential scoring 16 according to FIG. 2; the junction lies in the area of the weld seam 40, which connects the two longitudinal edges 12 and 14 to one another. From this junction, the further tearing open follows the two circumferential scratches 16, as shown in FIG. 1.

Die Lasche 20 ist ebenso breit wie der Abstand zwischen den beiden Umfangsritzungen 16 und ist mit dieser gemäss Fig. 2 in einer Schweisszone 42 verbunden, die sich über ungefähr 90% des Zwischenraumes zwischen den beiden Umfangsritzungen 16 erstreckt. In der Schweisszone 42 ist die Lasche 20 mit einer vorgefertigten, d.h. vor dem Aufschweissen vorhandenen Profilierung versehen, die gemäss Fig. 3 von scharfkantigen Längsrippen 43 gebildet ist und beim Aufschweissen mehr oder weniger flach gedrückt wird.The tab 20 is as wide as the distance between the two circumferential scratches 16 and is connected to it according to FIG. 2 in a welding zone 42 which extends over approximately 90% of the space between the two circumferential scratches 16. In the welding zone 42, the tab 20 is provided with a prefabricated, i.e. provided before the welding on, which is formed according to FIG. 3 by sharp-edged longitudinal ribs 43 and is pressed more or less flat when welding.

Die in Fig. 4 dargestellten Einzelheiten sind gegenüber Fig. 3 dadurch abgewandelt, dass der äussere Längsrand 12 am Anfang jeder der beiden Unfangsritzungen 16 eine Kerbe 44 und zwischen diesen Kerben eine sichelförmige Aussparung 46 aufweist. An der Lasche 20 ist als Profilierung ein Paar Warzen 48 ausgebildet, die je einem der Längsränder der Lasche verhältnismässig eng benachbart sind und Gewähr dafür bieten, dass die Lasche bis in unmittelbarer Nähe ihrer Längsränder mit dem Anfang des Aufreisstreifens 18 verschweisst wird.The details shown in FIG. 4 have been modified compared to FIG. 3 in that the outer longitudinal edge 12 has a notch 44 at the beginning of each of the two circumferential scratches 16 and a crescent-shaped recess 46 between these notches. A pair of warts 48 are formed on the tab 20 as profiling, each of which is relatively closely adjacent to one of the longitudinal edges of the tab and ensures that the tab is welded to the start of the tear strip 18 in the immediate vicinity of its longitudinal edges.

Zum Schweißen des Dosenrumpfes 10 eignet sich eine Vorrichtung mit einem ortsfesten Arm 50, an dem eine innere Elektrodenrolle 52 gelagert ist, deren Mantelfläche 54 nur etwas breiter ist als 0,4 mm, die Überlappungsbreite der beiden Längsränder 12 und 14. Der inneren Elektrodenrolle 52 steht eine äußere Elektrodenrolle 56 mit einer entsprechend schmalen Mantelfläche 58 gegenüber, die an einem radial zum Arm 50 hin- und herbewegbaren Stößel 60 gelagert ist. Der Blechzuschnitt 28 wird in üblicher Weise um den Arm 50 herum gerollt und zwischen den beiden Elektrodenrollen 52 und 56 hindurchgeführt, wobei die Schweißnaht 40 in Form einer Überlappt-Quetschnaht zwischen den beiden Längsrändern 12 und 14 entsteht.A device with a fixed arm 50, on which an inner electrode roller 52 is mounted, the lateral surface 54 of which is only somewhat suitable, is suitable for welding the can body 10 is wider than 0.4 mm, the overlap width of the two longitudinal edges 12 and 14. The inner electrode roller 52 is opposed by an outer electrode roller 56 with a correspondingly narrow lateral surface 58, which is mounted on a plunger 60 which can be moved radially to the arm 50. The sheet metal blank 28 is rolled around the arm 50 in a conventional manner and passed between the two electrode rollers 52 and 56, the weld seam 40 being formed in the form of an overlapped crimped seam between the two longitudinal edges 12 and 14.

Am Arm 50 ist in Bewegungsrichtung des entstehenden Dosenrumpfes 10 hinter der inneren Elektrodenrolle 52 eine ortsfeste innere Elektrode 62 angeordnet, die eine zylindrische, dem Krümmungsradius des Dosenrumpfes 10 entsprechende Stromübergangsfläche 64 aufweist. Dieser inneren. Elektrode 62 steht eine äußere Elektrode 66 gegenüber, die eine schneidenförmige Stromübergangsfläche 68 aufweist und taktweise radial zum Dosenrumpf 10 hin- und herbewegbar ist.Arranged on the arm 50 in the direction of movement of the resulting can body 10 behind the inner electrode roller 52 is a stationary inner electrode 62 which has a cylindrical current transfer surface 64 corresponding to the radius of curvature of the can body 10. This inner one. Electrode 62 is opposed to an outer electrode 66, which has a cutting-shaped current transfer surface 68 and can be cyclically moved back and forth to the can body 10.

Claims (6)

1. A tear-open can body (10) made from a sheet metal blank (28) having
an outer (12) and an inner (14) longitudinal edge which are welded to one another in an overlapping manner,
at least one pair of circumferential scorings (16) which extend round the can body transversely to the longitudinal edges (12, 14) and define a tearing strip (18) laterally, and
a tongue (20) which extends the tearing strip (18) beyond the outer longitudinal edge (12),
characterised in that the tongue (20) is welded, as a separate sheet-metal part, to the outer longitudinal edge (12), and that the starting scoring (30) has a spacing (c) from the outer longitudinal edge (12), which is three to seven times, preferably five times, as great as the thickness (a) of the sheet-metal blank (28).
2. A can body as claimed in Claim 1, characterised in that the starting scoring (30) extends beyond the two associated circumferential scorings (16) by a distance (d) which is two to three times as great as the thickness (a) of the sheet-metal blank (28).
3. A can body as claimed in one of the Claims 1 or 2, characterised in that the tongue (20) is welded to the outer longitudinal edge (12) over 85 to 95% of the width of the tearing strip (18).
4. A can body as claimed in any one of Claims 1 to 3, characterised in that the outer longitudinal edge (12) comprises a notch (44) at the beginning of each of the circumferential scorings (16).
5. A can body as claimed in any one of Claims 1 to 4, characterised in that the tongue (20) has a preformed profiling formed by sharp- edged longitudinal ribs (43), at least in the welding zone (42) which connects it to the outer longitudinal edge (12).
6. A can body as claimed in any one of Claims 1 to 5, characterised in that the tongue (20) consists of sheet metal having a greater strength than the sheet-metal blank (28).
EP85107150A 1984-07-12 1985-06-11 Tearable box body Expired - Lifetime EP0167855B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85107150T ATE52477T1 (en) 1984-07-12 1985-06-11 PULLABLE CAN BODY.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH303484 1984-07-12
CH3404/84 1984-07-12

Publications (3)

Publication Number Publication Date
EP0167855A2 EP0167855A2 (en) 1986-01-15
EP0167855A3 EP0167855A3 (en) 1987-11-19
EP0167855B1 true EP0167855B1 (en) 1990-05-09

Family

ID=4247140

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85107150A Expired - Lifetime EP0167855B1 (en) 1984-07-12 1985-06-11 Tearable box body

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EP (1) EP0167855B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH682906A5 (en) * 1984-09-25 1993-12-15 Elpatronic Ag Openable can member and method and apparatus for its production.
CH658034A5 (en) * 1985-04-09 1986-10-15 Elpatronic Ag TORNABLE CAN PART.

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2753075A (en) * 1951-12-24 1956-07-03 American Can Co Tear open container with separate tongue
US2806628A (en) * 1955-05-27 1957-09-17 Raytheon Mfg Co Tear tabs for tin cans and methods for forming them
DE1017042B (en) * 1955-10-21 1957-10-03 Continental Can Co Tin can with overlapped welded longitudinal seam and tear strips on the circumference of the fuselage

Also Published As

Publication number Publication date
EP0167855A3 (en) 1987-11-19
EP0167855A2 (en) 1986-01-15

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