Method and apparatus for producing tubular hollow items

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method and an apparatus for producing tubular hollow items, in particular for containers, from card material or the like.

BACKGROUND OF THE INVENTION

Within the scope of the invention, card material is also understood to mean a flat card which is laminated at least on one side, but preferably on both sides, with a plastic film. In particular, this is PE-coated card. However, the invention also includes all other flat or film-like materials, in particular single or multiple layer plastic films or foldable composite materials with aluminium coating. The plastic lamination is hot bonded or welded after the connection regions of the blank have been placed one on top of the other so that they overlap. When a pure card material is used, a weldable plastic intermediate layer is used in the form of a strip or a bond, for example by means of a hot adhesive or the like.

Methods and apparatuses of the above type are known especially in the production of packages for liquids. In this case, tubular hollow items are produced from a card material, are subsequently closed at one end, filled and, in a final step, also closed at the second end.

In DE-A 22 335 111, for example, a method and an apparatus for winding a multicomponent web to form a cylindrical hollow item from card material is disclosed, according to which the web, unwound from a roll, is partially inserted into a slotted sleeve in which a tube is rotatably arranged as a mandrel and, together with the sleeve, forms a receiving space. By means of a rotational movement, a section of the web is wound around the mandrel in the receiving space and is subsequently conveyed out of the bending station. To increase the efficiency of the apparatus, four slotted sleeves are in use, offset in cycles on a large wheel, as a result of which, however, the apparatus is mechanically complex and the constructional size increases considerably. Moreover, one sleeve remains unused, seen over one revolution of the wheel, by virtue of the principle, which impairs the degree of utilization of the system. Adaptation to cross-sectional areas of the hollow items other than round is also not possible. Furthermore, the apparatus described is used only for producing diaphragms. It does not provide for any connection of the cylindrical hollow item in the overlap region at longitudinal edges of the blank running parallel to one another. Moreover, when using modern packaging materials or coated card materials, on account of sliding friction this apparatus harbours the risk of damaging the coating and further mechanical problems due to the constructional size of the apparatus based on the principle.

A method for the continuous production of tubular packaging items from flat card-material blanks is described in DE 28 50 882 A1. According to this methods, when it runs through a bending apparatus a blank is bent continuously to form a cylindrical hollow item whilst forming a overlap region of the edges of the blank in the direction of transport. The overlap region is provided with an adhesive and, when the hollow item is transported away out of the bending apparatus, it is squeezed together and thus connected. A process of this type based on gradual deformation requires great outlay for transporting apparatuses and a considerable constructional length of the bending apparatus and thus also of the entire device.

GB-A 2 124 140 discloses a method of producing hollow items where blanks are processed by means of movable bending apparatuses while being transported in a bending station. A forming mandrel defines the form of the cross section of the hollow items to be produced. According to the disclosure the hollow items have a rectangular cross section. This method always uses the transfer of the carton blank from a work II to another work station llll to fold a sealing tab preparing the final step of connecting two longitudinal edges. After reaching the final position the bending operation is finished with closing the hollow item around a mandrel. A ultrasonic sealing horn serves as a connection means seaming and sealing the area of connection. This kind, of sealing doesn't protect the cutting edge of the laminated carton blank lying inwardly for a very long time against any kind of moisture occurring from an inner filling of the container during the time of use.

There is a very large requirement for packages which are based on tubular hollow items with a wide variety of cross-sectional areas as a preproduct. The costs for the package now make up a significant portion of the cost of the packaged product. Here, it is precisely those production steps carried out away from the filling operation that make the package considerably more expensive. The object of the present invention therefore consists in providing a method and a compact apparatus with a mode of operation which is as simple and reliable as possible to improve the efficiency and thus to reduce the costs in the production of known packages which are used predominantly for liquids and/or long-life foodstuffs.

According to the invention, a method of producing tubular hollow items having the following steps is proposed:

transporting a blank, bounded by longitudinal edges, or a web of card material or the like, from which the blank is separated, into a bending station,

the blank or the web being bent by guide elements acting as a bending apparatus and

then being held stationary in the bending station and being bent by means of movable bending apparatuses into the finished shape of the hollow item and

an overlap region being formed, in which the two longitudinal edges of the blank, which are parallel to the longitudinal axis of the hollow item, are placed one on top of the other and

are connected to one another and the hollow item being conveyed out of the bending station.

The subject-matter of the invention is also an apparatus according to Claim 28 to be preferably applied to carry out the method according to the invention.

The method according to the invention achieves the object set above in that it advantageously combines a continuous bending process with a stationary bending process. In a first step of the method, the blank or a web of card material is bent continuously by means of rigid guide elements when it is introduced into a bending station. When the web has been fixed, a defined section is produced, if the card material is not used in the form of blanks. In both cases, the blank or section is already present and is held stationary in the bending station for further treatment. Movable bending apparatuses then take over the final part of the shaping operation up to the finished shape of the intended hollow item. In this case, an overlap region is formed, in which the two longitudinal edges of the blank, running parallel to the longitudinal axis of the hollow item, are placed one on top of the other and are connected to one another in a final step. The hollow item finally shaped and closed by means of these production steps can then be conveyed out of the bending station

Since, in a method according to the invention or in an apparatus constructed for its utilization, the introduction of a blank or a web is also used at the same time for prebending the card material, the operating path of the movable bending apparatuses is small compared to pressers, folding arms and the like, such as are known, for example, from DE-A 25 12 852. Any reduction in movement also reduces the wear on bearings or guides, reduces the consumption of operating auxiliaries, such as for example oils and greases, and also reduces the energy requirement of such a plant.

Furthermore, an apparatus operating according to the method according to the invention is distinguished by a small constructional size, since, in particular due to the superimposition of continuous and stationary shaping, the distances or the radius of movement and the sizes of the parts to be moved are minimized compared to the prior art. The individual steps of the method mesh with one another in an interactive manner and may also be superimposed, so that in total short cycle times can be achieved. An apparatus according to the invention can therefore also be transferred to the filling machine to produce tubular hollow items as a preliminary stage for the production of packaging items. In this case, the card material can be introduced into an apparatus according to the invention either in the form of blanks or as an endless web. The cutting unit, which is superfluous when a blank is used in the apparatus, can then slide or serve to control the dimensional accuracy of the blanks. This does not affect the extended function of the cutting unit, claimed in particular in subclaim 11 with reference to preceding subclaims, during the cutting step.

When it is supplied in the form of an endless web or a prefabricated blank, the card material is precisely positioned at the same time in the plant and is also advantageously already present by means of guide elements. These guide elements are configured in the manner of rails and have a curved section, so that they bend the present material at least partially around a mandrel. The guide elements can thus interact with the mandrel for guiding and shaping. To retain a predetermined precise position, the blank or the web is preferably clamped tightly, preferably using a presser, when it reaches a predetermined insertion length.

The blank transported into the bending station is held tightly there in a stationary manner and without further transportation—as in other known bending and folding devices—is bent or folded around the mandrel at that location to form a tube of the respectively required cross-section by means of movable bending tools, in which case it is placed at least partially against the mandrel. This procedure permits efficient production of the tubular hollow items without considerable space requirement and outlay for machinery. The method according to the invention can therefore readily be arranged upstream of all known filling processes. The incorporation of the method according to the invention into the filling operation permits rapid reaction and adaptation of the package to different requirements, such as in particular changing package sizes and/or equipment variations. Such changes in the type of web or blanks can be carried out virtually without any outage times. For the filling operation, due to the production of the package on site, this opens up new possibilities of requirement-oriented and efficient production.

In a preferred embodiment, the bending is carried out on the present section, with the position being fixed in the apparatus, by means of bending tools which are each rotated about their own attachment points in the bending station. After the step of positioning and cutting of the web, movable bending tools thus take over the further process of shaping the blank. For this purpose, they preferably engage at least partially in a finger-like manner through the stationary elements of the bending station and, in the process, bend assigned parts of the blank.

With the completion of the bending operation, an overlap region is produced by a pressing unit in the region of the longitudinal edges with the bending tools closed. This region is connected in the bending station by being pressed together and preferably welded or bonded, so that the hollow item thus produced is fixed in a sealing manner by welding the seam of the hollow item. Precisely during welding, it is advantageous if at least part of the mandrel is arranged below the overlap region and the pressing or welding unit can thus serve as a counter-piece. For this purpose, according to Claim 7, part of the mandrel is advantageously configured as an anvil part between which and the pressing unit at least one spot-type weld of the overlap region can be carried out. According to Claim 8, this type of permanent fixing is carried out in modern, durable packaging materials, in particular by welding at least one plastic layer or plastic coating present in the overlap region.

During the fixing operation, the movable bending tools can already be opened again since the connecting region between the anvil part and the pressing unit is held securely. The finally shaped hollow item is thus secured against undesirable deviations in shape around the mandrel. By additionally opening the presser and by moving further elements, such as for example an insertion aid, back into their starting positions, a new section or part of a web can already be inserted into the bending apparatus below the hollow item to be fixed or to be welded, that is to say between the mandrel and the guide rails. Thus, in turn, two operations which are separate in terms of the process are superimposed here. Much time and energy can thus be saved, see Claims 9 and/or 10.

In the refinement of the method according to the invention, specific features have to be taken into account for packages. For instance, in the case of plastic-coated liquid packages, and in particular for packages with very long-life moist or liquid contents, it is necessary to protect at least one cut edge of the blank, located on the inside in the finished package, against the ingress of moisture or liquid into the core material. For these particular conditions of use, on packages a so-called bent-over or folded-over seam is preferably used, namely an additional longitudinal edge folded out-wards in the overlap or connecting region. In the case of card material coated with a plastic film on both sides, the longitudinal edge located on the inner side in the overlap region of the later seam is folded over towards the outside of the package and is covered by the longitudinal edge on the outside of the package. In the three-layer arrangement thus formed, the plastic coatings of the individual layers always rest against one another. These plastic layers can advantageously be connected to one another in a sealing manner, for example in a welding operation, without using an additional adhesive or further materials.

Known methods, compare for example DE 35 31 663, for producing a folded-over seam are always constructed in several steps and nevertheless ultimately provide imprecise seam points. In this case, it very often happens that the longitudinal edges of the folded-over seam to be welded are displaced relative to one another, such that the continuity in the design of the package cannot be maintained. In contrast, according to the present invention, a folded-over seam is produced in an efficient and reliable manner with a precise position in the edge region or in a central region. Based on the subsequently described exemplary embodiments, it can be seen that the method according to the invention can also be used for other package and seam shapes and seam arrangements.

According to Claim 11 in the production of a tubular hollow body with a folded-over seam, the material is prefolded during the production of a defined blank in the cutting operation in the region of the cut edge thus produced, in such a way that a first longitudinal edge is already produced here with an additional longitudinal edge prefolded on it. This longitudinal edge is advantageously used, applying a simple toggle lever mechanism, to produce the folded-over longitudinal seam on the package edge or in its central region. According to Claim 12, the additional longitudinal edge is simply formed by the fact that it is bent around a folding edge during the cutting operation by means of a top cutter. The additional longitudinal edge is advantageously determined in its width and area shape by the cross-sectional shape of the top cutter.

Furthermore, both the shaping body or the mandrel and the bending tools are adapted at their contact surfaces, at which they come into contact at least partially with the blank, to the desired final shape of the hollow item to be produced. Complete correspondence is thus not required.

For the method according to the invention and in the apparatus according to the invention, web or blank material with prestamped scoring lines can readily be used. By bending the blank around these scoring lines, very precise folding edges or corners can be produced in a simple bending process. As an alternative thereto, according to a further development of the method according to the invention according to Claim 23, scoring lines are impressed on the card material directly before the cutting operation. At the sites of these scoring lines, the material is prepared in a precisely defined manner so that edges of the later hollow item already form at the scoring lines merely due to the bending of the web or the blank in the stationary guide elements of the bending station. This bending or folding operation can be further reinforced by suitable shaping of the mandrel profile, advantageously also together with the guide elements. Correspondingly, in a method according to the invention, not only hollow items with a circular or oval cross-section, but also those with a triangular, square or rectangular or other polygonal cross-section can be produced efficiently and precisely.

A pressing unit is arranged at the bending station for acting on the overlap region of the three-dimensionally shaped blank. According to the invention, its object is to squeeze together the longitudinal edges of the blank, which are fed precisely on above the other or placed one on top of the other in the overlap region, according to Claims 15-17. By means of a multi-part construction explained below with reference to several exemplary embodiments according to the apparatus Claims 42-48, the pressing unit ensures very precise positioning of the longitudinal edges of the blank both relative to one another and in relation to the mandrel. This advantageously ensures the exact position and precise shaping of the seam on the hollow item to be produced.

According to a further development, the pressing unit is configured as a combination tool in such a way that it can carry out the prescribed positioning and squeezing of the longitudinal edges and produce a sealing weld of the longitudinal edges in the overlap region. Furthermore, the pressing unit comprises a welding tool, preferably in the form of a Sonotrode which is used at the same time as a pressing ram. In an apparatus according to the invention, in the case of a folded-over seam, external fixing and a liquid-tight connection in the overlap region are thus possible in a welding operation by welding the first longitudinal edge to a second longitudinal edge of the blank.

The supply of material can take place in an apparatus according to the invention in a known manner in the form of blanks or from a roll of an endless material web, as already explained above. Adaptation of the apparatus can be carried out quickly by setting up an insertion region on the bending station and different programming of the control. In a particularly advantageous further development, the endless web is removed from a store, for the production of which it is folded in a concertina-like manner. With concertina-like folding or fanfolding, a rectangular outside shape advantageously results for example for a wrapper as external protection and a transport and storage container of the web material. Using ordinary conveying apparatus, such as forklift trucks, etc., such wrappers can be transported and also stored more easily, in particular on pallets, than roll material. Moreover, with a fanfold, outer surfaces and inner surfaces of the later package are always in contact with one another respectively. For a hygienically satisfactory package, any transfer of soiling, for example from an outer surface to an inner surface, is thus ruled out. Simple and rapid removal or drawing-off of the web material folded in this manner results, for example, from the fact that the wrapper is opened at a top side parallel to the folded web parts located below. The web can then be pulled continuously out of the wrapper without difficulty in the direction of its longitudinal axis and fed to the bending station. However, a significant factor in the proposed storage or provision of the web material in a fanfold is the fact that, according to Claim 25, the web material is provided with a perforation in each case at the folding edge of the fanfold. During the production of the web material, this creasing region can alternatively also be provided with a semi-cut. By no means of this particular measure which can easily be integrated in the production process, the storage volume of the outer packages can be greatly increased by the higher stacking density of the material, since the creasing region located in each case at the outer edges thus does not curve up in relation to the central regions of the fanfold lying in a stack.

The web material is advantageously fed to the cutting operation directly from a wrapper. This is very simple and space-saving compared to known methods for the charging of apparatuses for the production of packaging preproducts or hollow items. In a further development according to Claim 26, the folding of the web is pulled apart in parts which each correspond to the length of a blank or a multiple of the said length. In this fixed dimension predetermined by the type of package, compact stacks are formed in a fanfold, the creasing region no longer being noticeable in the finished package or the welded hollow item.

A plurality of webs are advantageously arranged adjacently, for example in stacks, in the store or the wrapper. In particular, in this arrangement, a plurality of webs can also be removed simultaneously in parallel from the wrapper.

The applicant reserves the right to establish independent claims for the individual units of the apparatus in which steps of the method described are in each case implemented technically in an innovative manner. It is clear from the preceding description of their respective function that the advantages emerge not only in the interaction of the units in an apparatus according to the invention. On the contrary, the units can also be used advantageously in other machines, for example as a replacement for specific elements of a plant according to the prior art. The content of the claims 2-48 is incorporated herin by reference without repeating the claims.

BRIEF DESCRIPTION OF DRAWINGS

Exemplary embodiments of the invention are explained in greater detail below with reference to the drawing, in which:

FIG. 1

shows a side view of the principle construction of an apparatus for producing tubular packages in a first embodiment;

FIG. 2

shows a side view of the apparatus of

FIG. 1

with drives, partially in an operating position which is different from that in

FIG. 1

;

FIG. 3

shows a front view in relation to

FIGS. 1 and 2

;

FIG. 4

shows a plan view of a part of the apparatus from

FIGS. 1 and 2

;

FIG. 5

shows a perspective illustration of the apparatus from

FIGS. 1 and 2

;

FIGS. 6

a-

6

l

show a diagrammatic illustration of the sequence of the apparatus from

FIG. 1

in individual steps;

FIG. 7

shows a simplified illustration of a filling machine whose first part comprises an apparatus for producing tubular packages;

FIG. 8

shows a diagrammatic illustration of individual steps of the processing of web material;

FIGS. 9

a,

9

b

show perspective illustrations of wrappers for the storage and use of the card material;

FIG. 10

shows a simplified side view of an apparatus for producing a simple longitudinal seam which is not folded over;

FIG. 11

shows a detail from

FIG. 10

;

FIG. 12

shows a perspective illustration of a part of a pressing tool from FIG.

10

and

FIGS. 13

a-

13

g

show a diagrammatic illustration of the sequence in an alternative apparatus for carrying out the method.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS

FIG. 1

illustrates a first embodiment of an apparatus

1

according to the invention in a side view. In the apparatus

1

illustrated, hollow items with a square cross-section are produced, in which the seam is folded over and the seam point lies along an edge of the hollow item as will be explained.

In the step of the method illustrated, a web

2

of a card material which is PE-coated on both sides is inserted into a bending station

5

by a conveying unit

3

through a cutting unit

4

. The conveying unit

3

is configured as a roll or roller drive and comprises a free-running and spring-loaded nipping roll

6

above the web

2

and a driven roller

7

below the web

2

. The control of the conveying unit

3

will be detailed below.

The web

2

runs through the cutting unit

4

, comprising a top cutter

8

and a bottom cutter

9

, in an opened state. In the position illustrated in

FIG. 1

, a comb-like folding edge

10

is located opposite the top cutter

8

approximately at the same level as the bottom cutter

9

. During the cutting operation, the folding comb

10

can be understood as a constituent part of the cutting unit

4

on account of its function which will be described in detail in the description of the operations during cutting.

The web

2

, is inserted into the bending station

5

below an insertion aid

11

. The bending station

5

comprises fixed and movable parts. In the process step illustrated, the web

2

behind the insertion aid

11

is only in contact with immobile parts. Thus it is transported further on guide rails

13

with the assistance of the insertion aid

11

between a mandrel

12

and the guide rails

13

and, in the process, is bent upwards by a curved section of the guide rails

13

and is thus already partially prefolded.

Scoring lines

14

(not illustrated) have previously been impressed in the web

2

. At these scoring lines

14

, the web

2

creases in the curved section of the guide rails

13

, and the later edges of a tubular hollow item

15

to be produced are already formed here. Without the scoring lines

14

, hollow items

15

with a circular or elliptical cross-section can also be produced with or even without a folded-over seam by adaptation of the apparatus

1

.

Mounted below the guide rails

13

are two bending tools

16

,

17

which are pivotable on axes

18

,

19

. The tubular hollow item

15

is closed by the bending tools

16

,

17

after the cutting operation and is held closed until a pressing unit

20

, arranged at the upper end of the guide rails

13

, terminates the bending operation and produces the seam on the hollow item

15

.

Also arranged below the guide rails

12

of the bending station

5

is a presser

21

which fixes a blank

22

in its position which blank is obtained during and after the cutting of the web

2

. Consequently, the cutting of the web

2

is associated with the production of a prefolded additional longitudinal edge.

The end product produced in the apparatus

1

is then the tubular hollow item

15

which is open at both end faces and is discharged from the mandrel

12

by a slide

23

illustrated by dashed lines in FIG.

1

.

FIG. 2

shows the side view of

FIG. 1

, taking into account further elements of the apparatus

1

. For instance, it can be seen in

FIG. 2

that the web

2

is guided over a table

24

with guides

25

to the conveying unit

3

up to the cutting unit

4

.

Furthermore, the drives necessary for operating the apparatus

1

in this embodiment are indicated in FIG.

2

. The roller

7

is driven by a motor A

1

, and the cutting unit

4

is driven by a pneumatic drive A

2

. By means of a lever control, a further pneumatic drive A

3

drives essential parts of the bending station

5

, namely the insertion aid

11

and the bending tools

16

and

17

. The cutting unit

4

can be operated in a cycle together with the presser

21

. Here, however, the presser

21

is provided with its own drive A

4

. A drive A

5

of the pressing unit

20

and a drive A

6

of the slide

23

are only indicated.

FIG. 3

illustrates a front view of the apparatus

1

in the form illustrated in FIG.

2

. For reasons of clarity, some of the abovementioned drives and parts have not been illustrated or have been cut. The table

24

in

FIG. 3

has been partially cut to give an at least partial illustration of the lever connections.

In the illustration of

FIG. 3

, the maximum width d of the web

2

to be processed is specified. Indirectly it prescribes the height of the hollow items or packaging preproducts To adapt, for example, to liquid packages with a smaller volume, the width of the table

24

is adjustable by moving the lateral guide

25

(not illustrated here in detail).

FIG. 4

illustrates the apparatus

1

of

FIG. 2

in a plan view, drive elements again having been cut or omitted for reasons of clarity. The table

24

with the guides

25

can be seen in FIG.

4

. Indicated on a non-adjustable lateral guide

25

a

of the table

24

is a measuring cell

26

which controls the drive A

1

of the conveying unit

3

by optical scanning of reading markers made on the web

2

.

Furthermore, the arrangement and the course of individual parts of the bending station

5

can be seen referring to FIG.

4

. Thus, for example, the guiding of the inserted web

2

by individual guide rails

13

is illustrated. Furthermore, the finger-like construction of the bending tool

17

is illustrated, where the bending tool

17

in the form of individual levers can be inserted between the guide rails

13

for bending the web

2

by rotation about the axis

19

.

In this plan view, the transition region from the table

24

to the conveying unit

3

and cutting unit

4

is also illustrated. From the cutting unit

4

, the web

2

is fed into the bending station

5

between the insertion aid

11

and the adjacent ends of the guide rails

13

.

FIG. 5

is a perspective illustration of the apparatus from

FIGS. 2

to

4

. The measuring cell

26

is illustrated in the region of the fixed lateral guide

25

a

on the table

24

. This illustration shows the compact construction of the apparatus

1

with the conveying unit

3

, the cutting unit

4

with a folding comb

10

, the insertion aid

16

, the bending station

5

and the pressing unit

20

arranged above the bending station

5

.

The mandrel

12

as part of the bending station

5

has a guide track

27

for the slide

23

, illustrated with its drive A

6

, of a sliding unit

28

and, on the other hand, for an anvil

30

. The anvil

30

serves as a counter-piece to the combination tool of the pressing unit

20

which will be described later with reference to FIGS. of several embodiments.

With reference to a sequence of FIGS. based on the construction of the apparatus of

FIG. 1

, the method of operation and functional sequence of the apparatus during a complete cycle is illustrated below.

FIG. 6

a

shows the web

2

which is inserted up to a predetermined length into the bending station

5

between the insertion aid and the guide rails

13

below the mandrel

12

. In the situation the measuring cell

26

(not illustrated here) detects a reading marker on the underside of the web

2

and stops the conveying unit

3

FIG. 6

b

illustrates the next process step in which the cutting unit

4

is closed. In this case, a precisely determined piece is separated from the web

2

and is then further processed as a blank

22

in the bending station

5

. For precise adherence of the dimensions of the blank

22

, the web

2

is fixed directly before the cutting operation by the presser

21

in that it is clamped from below against the mandrel

12

by the presser

21

between the guide rails

13

.

During the cutting operation, the web is separated between a top cutter

8

and a bottom cutter

9

, the blank

22

thus produced being prefolded always with the same dimensions by the top cutter

8

at a folding edge

10

.

In

FIG. 6

c,

the blank

22

, which is fixed in its position by the presser

21

, is made further into the shape of the tubular hollow item to be produced by the bending tools

16

and

17

. To do so, the blank

22

is bent or folded around the mandrel

12

in the bending station

5

, the edges of the side walls of the later hollow item being formed at the points of the scoring lines

14

.

During this operation, the insertion aid

11

is not used and is therefore moved into a rest position, in which case, at the same time, it frees the space required for the movement of the bending tool

16

. In this case, the attachment or axis

18

of the bending tool

16

is offset in relation to the scoring line

14

a,

around which the rear part of the blank

22

is bent, in such a way that, when the bending tool

16

is placed against the mandrel

12

, the prefolded region of the blank

22

rests securely with its cut edge against the folding comb

10

—with-out protruding.

FIG. 6

d

shows the apparatus

1

in the almost completely closed state. The bending tools

16

and

17

are illustrated in their end position. The blank has already been bent to the extent that the shape intended for the hollow item has already almost been reached. The pressing unit

20

is then lowered from above on to a region of the mandrel

12

configured as an anvil

30

. Here it is important to arrange the prefolded region of the first longitudinal edge below the second longitudinal edge. For this purpose, the pressing unit

20

is of two-part construction. As the first part, a comb part

31

is lowered on to the already prefolded region. In this case, the comb part

31

engages in recesses in the folding comb

10

which, is attached to the end of the bending tool

16

, thus preventing the longitudinal edge from being trapped during the closing movement described. The comb part

31

is attached in a sprung manner to a welding tool

32

, advantageously designed as a Sonotrode. These two parts can thus be moved together as the pressing unit

20

by the drive A

5

(not illustrated here).

FIG. 6

e

shows the bending and folding operation with the lowering of the fixing unit

20

in its end phase where the later overlap region

29

acting in the way of a simple toggle-lever mechanism. Here the folding comb

10

and comb part

31

mesh with one another and press the first longitudinal edge

33

with the prefold inwards, so that, by the second longitudinal edge

35

being bent over by the welding tool

32

, as a result a folded-over corner seam is formed between the welding tool

32

and the anvil part

30

of the mandrel

12

, which corner seam is made up of the first longitudinal edge

33

, an additional longitudinal edge

34

and a second longitudinal edge

35

.

With the transition to

FIG. 6

f,

the bending and folding operation is terminated by the complete lowering of the pressing unit

20

. In the overlap region

29

of three-layer construction, a folded-over longitudinal seam is welded in the single-stage method illustrated. At the same time, the cutting unit

4

is opened again by raising the top cutter

8

, and the presser

21

is lowered to release the clamping on the mandrel

In

FIG. 6

g,

the welding of the longitudinal seam

36

between the welding tool

32

and the anvil part

30

is continued, while the bending tools

16

and

17

are also being opened again and the insertion aid

11

is being moved back into the position of

FIG. 6

a.

In the position of

6

f

or

6

g

it is possible in a very simple manner to integrate a bad sheet selection as an alternative process step in the apparatus. Therefore if an optical entry control has discovered a faulty blank

22

or a faulty region of the web

2

, the bending tool

16

can be held in the position illustrated. With appropriate shaping of the bottom edge of the bending tool

16

, the part of the web

2

or the blank

22

introduced into the apparatus can thus be deflected and, for example, conducted out of the apparatus

1

at the bottom. This faulty region thus does not even enter the bending station

5

at all. After the cutting operation, the apparatus

1

is again available as described above.

The opening operation is terminated in

FIG. 6

h,

and the bending tools

16

and

17

as well as the insertion aid

11

have again reached their starting positions. In this case, the welding operation on the folded-over longitudinal seam

36

is continued.

The apparatus

1

is thus prepared for receiving a further section of the web

2

and, as illustrated in

FIG. 6

i,

a new section of the web

2

can thus be introduced via the conveying unit

3

through the cutting unit

4

through a passage

37

between the hollow item

15

which is still in the process of welding and the guide rails

13

.

FIG. 6

k

illustrates how the web

2

is introduced into the bending unit

5

, while the welding or sealing of the longitudinal seam

36

of the hollow item

15

is still taking place, and is already prefolded there.

In the process step illustrated in

FIG. 6

l,

the welding of the longitudinal seam

36

on the hollow item

15

has been completed. At the same time, the positioning and the measurement of the correct length of the newly introduced section of the web

2

have also ended. The pressing unit

20

is thus lifted up again, as a result of which the now completed hollow item

15

on the mandrel

12

can be moved freely by the slide

15

, illustrated by dashed lines, and conveyed out of the apparatus

1

. The cycle is thus complete, and the method begins again with the process step illustrated in

FIG. 6

a.

It is clear from the entire sequence of

FIGS. 6

a

to

6

l

that the moved parts of the apparatus

1

have to travel short distances. This is achieved, above all, by the fact that the web

2

is already prebent by the round sections of the guide rails

13

when it is inserted into the bending station

5

and is thus kept at a low level in comparison to the plane of the longitudinal seam

36

and is already deflected and fed to this end position.

FIG. 7

shows a complete machine for filling and packaging liquid media in operation. The first part of the plant illustrated comprises two apparatuses

1

operating in parallel, as has been described above. The apparatuses are illustrated in a simplified form in the drawing. The web

2

is introduced into the apparatuses in each case from a store

38

, is cut to size, folded and welded. The finished, tubular hollow items

15

are conveyed in an intermediate step Z towards the right into the actual filling plant, the two-lane filling plant being commercially available in this form and only requiring slight adaptation to the new apparatus

1

. Each apparatus

1

thus feeds one lane of the filling machine. However, the apparatus

1

operates, in principle, far faster than the filling machine. The operations within the filling plant itself are known in principle and do not require a description here. The extra costs for the illustrated expansion of the filling machine are compensated after only a short operating period by the reduction in costs for packaging materials.

FIG. 8

shows a diagrammatic illustration of the sequence of the method within the apparatus

1

up to transfer of the finished hollow items into the known filling device. Here the web

2

, as already illustrated in

FIG. 7

, is removed from a store

38

. In this case the store

38

is a wrapper

39

in which the web

2

is arranged as a stack

40

with a fanfold or with concertina-like folding. The web

2

is produced by a pakkaging material manufacturer with a perforation

2

b

in the creasing region

2

a

of this folding and is placed in the fanfold in the wrapper

39

. By means of this perforation

2

b,

which may also be replaced by a semi-cut, the creasing region in the finished fanfold can be folded to be as low as the central region of the fold. Thus any curving-up of the folded creasing regions

2

a

in the wrapper

39

as minimizeded in favor, of an even greater storage capacity with the same outside dimensions. In this case, the wrapper

39

serves at the same time as a transporting and storage container. In addition to the finished printing and coating of the web

2

, the scoring lines

14

can also already be impressed on to the web

2

by the packaging material manufacturer. However, if the webs are forwarded to the operator of the apparatus

1

and to the connected filling machine in an unprocessed state in this regard, the scoring lines

14

and further applications, for example so-called pull tabs, can be made on the web

2

at the place marked by B in FIG.

8

.

The web

2

runs via the conveying unit

3

to the cutting unit

4

. As blanks

22

, they are folded in stages to become tubular hollow items is and welded and transported via an intermediate and transporting step Z into the filling machine.

In the manner illustrated, long-term charging of the apparatus

1

is possible without difficulty. In operation, this additionally reduces the personnel costs. Moreover, a rapid and simple exchange of design and even formats can be carried out. When the apparatus

1

is stopped, the web

2

is taken out of the conveying unit

3

and a new web

2

is inserted. The positioning of the new web

2

takes place automatically by means of the conveying unit

3

coupled to the measuring cell

26

, such that, due to the precise adherence to the dimensions of the blank, after the first blank no system-related wastage is produced.

FIGS. 9

a

and

9

b

present, in a perspective view, possible transporting and storage forms of wrappers

39

for fanfolded webs

2

for a different package size. With adaptation to dimensions in transport systems which are common in Europe and worldwide, about 2500 blanks are stored in a wrapper

39

in each case in two stacks

40

arranged adjacently in parallel. The type of storage of the web considerably increases the utilization of space compared to previously known storage methods for tubular hollow items

15

. According to a previously common method, only about 600 hollow items

15

can be stored in a wrapper. In the known systems, on the one hand the utilizational volume in the wrappers is far less efficient and, on the other hand, operating personnel are required to load the fillng machines, which means that the weight of the wrappers is limited overall by work safety regulations to less than 10 kg. Since, in the method described, no heavy physical work by operating personnel is necessary to reload individual hollow items

15

or the blanks

22

or here predominantly the webs

2

, the weight restriction for the wrappers

39

, passed for reasons of work safety, has no significance. The package sizes of the wrappers

39

can thus be freely adapted to the customary standard dimensions in transport systems. This results in total in less problematic storage and more efficient transportation.

A further advantage of the fanfold illustrated consists in the fact that in each case only printed outer surfaces or inner surfaces directed to the side of the later product are in contact with one another. Thus soiling on the inner surfaces can be ruled out.

Furthermore,

FIG. 9

a

shows four wrappers

39

arranged on a pallet

41

, so that on this pallet

41

alone, webs

2

for about 20,000 hollow items can be stored, transported and positioned in front of or below an apparatus

1

. In this example, the hollow items to be produced have a capacity of 1 liter of liquid.

FIG. 9

b

shows, similar to

FIG. 9

a,

webs

2

in fanfolded stacks

40

for hollow items which have a 0.5 liter filling volume in a filling machine. In one of the wrappers

39

illustrated, two stacks

40

, together comprising 5000 blanks, are arranged in parallel and can be removed at the same time, so that in total 30,000 blanks in the form of webs

2

are available on the pallet

41

.

The method described can be varied within broad ranges and can be adapted to different production conditions and cross-sectional shapes of hollow items. Hollow items

15

with a round or oval cross-section can thus be produce analogously by adapting the mandrel

12

and the bending tools

16

and

17

without scoring lines

14

having to be preimpressed on the web

2

or the blanks

22

. By making slight changes, hollow items

15

with a rectangular cross-section can also be produced using the apparatus illustrated in

FIGS. 6

a

to

6

l.

An embodiment of the method according to the invention has been described above from the viewpoint of the folded-over corner seam which is to be preferred and is slightly more complex in terms of production. For reasons of continuity of the package design, the folded-over corner seam is preferred today. By folding over the seam in the construction by inserting an additional longitudinal edge

34

on the first longitudinal edge

33

and the overlapping cover by the second longitudinal edge

35

, a seam is provided which is permanently strong and is liquid-resistant from the inside and is used, in particular, in foodstuffs with a long shelf life. Here the packaging material of the web

2

is coated with a PE-film on both sides and additionally has a closed aluminium lamination in order to prevent any light and oxygen entering the interior of the package.

In the sector of packaged foodstuffs with a relatively short shelf life, less complex card materials with simpler welded seams are used.

FIG. 10

shows an embodiment of the apparatus

1

for producing a corner seam which is not folded over in the production of tubular hollow items

15

. In contrast thereto, the apparatus

1

a

of

FIG. 10

comprises a simplified design of a cutting unit

4

a

since, when the web

2

is cut to form a blank

22

a,

no prefolding of an additional longitudinal edge

34

is necessary.

The process step illustrated in

FIG. 10

corresponds to that of

FIG. 6

e

of the first embodiment. Owing to the lack of an additional longitudinal edge

34

in

FIG. 10

, the construction of the folding comb

10

a

has to be changed in the manner illustrated in order to fold the first longitudinal edge

33

over in the region around the anvil

30

c

of the mandrel

12

.

FIG. 11

illustrates a detail from FIG.

10

. Here the region around the anvil

30

and the end of the welding tool

32

with longitudinal edges

33

and

35

guided or held between them is illustrated on an enlarged scale. It can be seen that, when the bending tool

16

is closed and the rear end of the blank

22

a

is pressed against the anvil region

30

of the mandrel

12

, the first longitudinal edge

33

is bent around the anvil region

30

around a scoring line

14

by means of an additional folding edge

10

b

on the modified folding comb

10

a.

The first longitudinal edge

33

thus lies below the second longitudinal edge

35

prior to the final lowering of the pressing unit

20

, and inner and outer plastic coatings

42

and

43

can be pressed one on top of the other and welded by the welding tool

32

on the anvil

30

.

FIG. 12

shows the position from

FIG. 11

in a three-dimensional illustration. The bending tool

16

is already completely closed, so that the folding edge

10

a

rests against the mandrel

12

, and the first longitudinal edge

33

is bent around the anvil

30

by the edge

10

b.

Furthermore, it can be seen here how the comb part

31

of the pressing unit

20

engages in the grooves or comb structure of the folding comb

10

a.

By means of the comb structure, it is ensured preferably in every embodiment of the invention that neither the first longitudinal edge

33

nor the second longitudinal edge

35

nor the additional longitudinal edge

34

(not present in the exemplary embodiment of

FIGS. 10

to

12

) can be trapped and thus destroyed between the folding comb

10

or

10

a

and pressing unit

20

when the pressing unit

20

is lowered.

FIG. 13

a

shows a further embodiment of an apparatus

1

c.

Here a folded-over seam in a central region of a tubular hollow item

15

is produced from blanks

22

c

separated from a web

2

. To do so, alternative embodiments of a cutting unit

4

c,

the bending tools

16

c,

17

c

and the pressing unit

20

c

are configured as illustrated in

FIG. 13

a.

In the sequence of

FIGS. 13

a

to

13

g,

the sequence of the method is illustrated below similar to

FIGS. 6

a

to

6

l.

In terms of the process step,

FIG. 13

a

corresponds to

FIG. 6

a.

Here the web

2

is inserted by the conveying unit

3

into a bending station

5

c

and is prefolded. However, at the leading end of the web

2

a,

in contrast to the first embodiment of

FIG. 6

a,

an additional longitudinal edge

34

c

has already been prebent here.

FIG. 13

c

is a momentary image of the cutting operation in which the blank

22

c,

thus positioned in the bending apparatus

5

c

and clamped tightly against the mandrel

12

c

by the presser

21

, is separated from the web

2

by the cutting unit

4

c.

FIG. 13

c

shows the conveying unit

3

together with the cutting unit

4

c

in an enlarged illustration. From this figure it can be seen that the cutting unit has been modified compared to the first embodiment in such a way that a folding edge

10

c

is arranged in each case on the first longitudinal edge of a blank. For transporting the additional longitudinal edge

34

c

beyond the bottom cutter

9

, it is possible either to lift the longitudinal edge

34

c

up or to move the bottom cutter

9

.

The illustration of

FIG. 13

d

corresponds to that of

FIG. 6

e

in the first embodiment and illustrates the almost completely closed bending station

5

c

with a tubular hollow item

15

c,

formed from the blank

22

c,

contained therein.

In an enlarged illustration of the pressing unit

20

c

from FIG. l

3

d,

the sequence of bending and folding directly before the pressing unit

20

c

is closed is illustrated in

FIG. 13

e.

The additional longitudinal edge

34

c

is moved, in the prefolded form, by the guide rails

13

below a comb part

31

c

of the pressing unit

20

c

in such a way that it is positioned in its prefolded state below the second longitudinal edge

35

. The comb part

31

c

takes over this function in that it immediately engages in a leading manner with the additional longitudinal edge

34

c

in the region of the ends of the guide rails

13

. The comb part

31

c

is thus arranged, disconnected from the welding tool of the pressing unit

20

c,

on a holder

44

so as to be lowerable downwards.

When the bending apparatus

5

c

is closed, the second longitudinal edge

35

strikes with its cut edge against the comb part

31

c

and is conducted downwards by the welding tool

32

. In the process, the second longitudinal edge

35

is positioned precisely.

The force for pressing the comb part

31

c

is transferred by the welding tool

32

on to the comb part

31

c

by the fact that, when it is lowered on to a part

45

of the comb part

31

c,

it presses against a restoring spring

46

and thus presses the comb part

31

c

down on to the blank

22

c.

In

FIG. 13

f,

the apparatus

1

c

is illustrated with the bending apparatus

5

c

completely closed and the pressing unit

20

c

lowered. The hollow item

15

c

with a folded-over central seam is closed around the mandrel

12

c,

and the longitudinal seam

36

c

can be welded in the process step illustrated.

FIG. 13

g

shows a detail from

FIG. 13

f

with the region around the longitudinal seam

36

c

arranged in the central region. Here it is clear how the comb part

31

c

lowered in front of the welding tool

32

serves as a stop for the second longitudinal edge

35

and thus guides the latter into a precisely predetermined position. Moreover, the comb part

31

c

holds the leading part of the blank

14

c

pressed down on the mandrel

12

c,

so that, by lowering the welding tool

32

, the first longitudinal edge

33

c

is placed with the folded-over additional longitudinal edge

34

c

below the second longitudinal edge

35

, and this construction can be welded after it has been squeezed together.

With the apparatus

1

c

described, by exchanging the cutting unit

4

c

with the cutting unit

4

a

from FIG.

10

and connecting the comb part

31

c

to the welding tool

32

in a similar way to the manner illustrated in

FIG. 1

, a hollow item can also be produced, which has a simple seam which is not folded over in its central region.

Number	Name	Date	Kind
4870804	Yokoyama	Oct 1989	A
4908009	Yokoyama	Mar 1990	A
5492588	Weder et al.	Feb 1996	A

Method and apparatus for producing tubular hollow items

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

PCT Information

US Referenced Citations (3)