WO1996018490A1

WO1996018490A1 - Cassette for securing a sleeve of packaging material

Info

Publication number: WO1996018490A1
Application number: PCT/EP1995/003819
Authority: WO
Inventors: Oliver Charriere; Charly Genoud; Hans-Peter Aeschlimann
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 1994-12-12
Filing date: 1995-09-27
Publication date: 1996-06-20
Also published as: AU3743095A

Abstract

A cassette for securing a sleeve of flexible packaging material which includes plastic has side walls (3-6), the first (4) of which has a more or less flat part for attaching the cassette (1) to a conveyor chain. To ensure that the long sealing seam of a newly made plastic sleeve cools and hardens effectively and in such a way that the cross-section of the sleeve when removed has a good degree of roundness, it is proposed that near the cassette (1) a second side wall (6) should be provided with a cooling strip (9) protruding beyond the height H of the cassette (1) and that two spaced counter-rests (12a, 12b) should be provided on the face opposite the cooling strip (9) in relation to the longitudinal central axis of the cassette (1).

Description

Cassette for holding a sleeve made of packaging material

The invention relates to a cassette for receiving and holding a sleeve made of flexible, plastic packaging material, with side walls, a first of which has an approximately flat part for attaching the cassette to a conveyor line.

An attempt has been made to e.g. to form a rectangular blank as a sheet of a foamed plastic material from a thickness range of 0.5 mm to 2 mm to form a sleeve, the two edges being overlapping. Attempts have been made to use such a sleeve as the tube body of a pack and to attach the base and lid to the ends of the sleeve in order to create a packaging. To seal the overlapping edges to form a so-called longitudinal seam of the sleeve, a mandrel is used, around which the sheet of foamed material is placed and which contains a counter jaw in the sealing area, against which a corresponding pressure jaw is pressed from the outside. It is understood that the application of heat to the edges to be sealed together changes the character of the foamed material because e.g. the air bubbles enclosed in a foamed plastic material disappear as the material melts.

If such a sleeve was produced by creating the longitudinal sealing seam and pulled off the dome, then if the sleeve was not properly treated further, it was found that the cross-section is not round, is generally oval in shape or even has a kink at the edge of the longitudinal sealing seam. This undesirable oval design is formed, among other things, by angled edges directly at the edge of the sealed seam. It is understandable that the subsequent attachment of the lid and base to such a sleeve with a deformed cross section leads to difficulties.

The object of the invention is therefore to provide a cassette with the features of the type mentioned, with which the cooling and curing of the longitudinal sealing seam of a freshly created sleeve made of plastic material takes place quickly, effectively and in such a way that the cross section of the removed sleeve has a good roundness .

This object is achieved in that a second side wall has a cooling strip extending over the height of the cassette and that two counter supports are provided at a distance from one another on the side located with respect to the longitudinal center axis of the cassette opposite the cooling strip. It took a long time and many Trials are required before it has been determined where improvements have to be made in the production machine in order to obtain a sleeve which, after the longitudinal seal seam has been produced and any further treatment, has a good roundness, preferably a circular cross section. According to the invention, it has been found that the type of cooling and hardening of the longitudinal sealing seam contributes significantly to how the cross-sectional shape is designed after the fresh production of the plastic sleeve. According to the invention, a cassette is used which receives the freshly created sleeve which has been pulled off the sealing mandrel and at the same time presses the not yet hardened longitudinal sealing seam flat onto a cooling strip.

It would have been easier to think of cooling the longitudinal sealing seam on the dome after the sealing process and, if necessary, keeping baking and counter-baking pressed on the sealing seam until cooling and hardening has taken place. Although this route is theoretically feasible, it would then take so much time in a pack-making machine or sleeve-molding machine that the low output would not be able to meet today's requirements. The invention therefore goes the way of taking the freshly produced sleeve into the cassette, holding it in the cassette and holding it in a conveyor line for a period of time until a bar specially designed for cooling has had sufficient contact with the longitudinal sealing seam for it to harden well is. Already with these considerations and with the first attempts it was shown that the cooling and curing time is essential.

The cooling times could be shortened even further if this were necessary, because the cassette with its cooling strip is accessible from the outside, so that one could even use water cooling or the like. However, it has been shown that this is not necessary if only one cooling strip is used which can absorb heat calories in the course of an already necessary transport route and can dissipate it from the longitudinal sealing seam.

This advantage is particularly successful if the sleeve area with the longitudinal sealing seam is pressed flat onto the cooling strip, so that there is a flat cooling contact. The contact area of the cooling strip should be larger than the area of the actual longitudinal sealing seam. In other words, the cooling strip should not only be Longitudinal seal seam itself, ie the two overlapping layers of material cool but also prefer the immediate neighboring areas. This prevents kinks and at the same time ensures good heat dissipation from the longitudinal seal seam into the cooling strip.

With the last-mentioned feature with the counter supports, this flat pressing succeeds of the sleeve area with the longitudinal sealing seam on the cooling strip is particularly useful, because with the counter supports you can force the sleeve edge areas next to the longitudinal sealing seam, e.g. edge strips with a thickness of half to the entire thickness of the longitudinal sealing seam on both sides of the same, against the cooling surface of the cooling strip.

It is particularly preferred here if the connecting line of the two counter supports, i.e. a line that is drawn from one counter support to the other, spans an isosceles triangle with the central contact line of the cooling strip, that the surface of the cooling strip facing the center of the cassette is flat and the corresponding surfaces of the counter supports are curved in such a way that the center of curvature is curved located outside the cassette. If you draw a line from the end of the connecting line of the two counter supports to the longitudinal center line of the cooling strip, then the isosceles triangle mentioned arises, this observation being made in the direction of view of the longitudinal center line, so that the cross section of the cassette can be seen. The cooling effect on the longitudinal sealing seam is increased by the planar design of that surface of the cooling strip which faces the sleeve to be cooled. At the same time, it has proven to be particularly advantageous to arch the counter supports in such a way that a line contact almost occurs in the cassette on the inside against the respective counter support sleeve. Then, during the stay of the sleeve to be cooled in the cassette, a certain deformation is exerted on the sleeve in such a way that the sleeve area with the longitudinal sealing seam also becomes almost flat and therefore lies flat on the flat cooling strip. The curvature of the counter supports then does not disturb the roundness of the sleeve, even if it experiences a certain pressure at the contact points of the counter supports. The sleeve is - seen in cross section - deformed so that the circle becomes a kind of egg shape, but this "bad" roundness is surprisingly removed after the longitudinal seal seam has been cooled and the sleeve has been released from the cassette, and the removed sleeve is circular in cross section. As soon as the pressure of the counter supports is removed and the longitudinal sealing seam has hardened, the "good" roundness, which is expressed in cross section in the circular shape, is produced in a desired manner.

In an advantageous further embodiment of the invention, as seen in cross section, two centering guides are arranged on the two arches, each between the counter support and the cooling strip, outside the isosceles triangle. This description of the arrangement of the centering guides refers again to the cross-sectional view of the cassette outside and the sleeve inside. As the word "centering guide" already suggests, these guide parts of the cassette provide slight pressure on the sleeve from the outside in, in the area of the material which appears in cross section as an arc and which is between the Counter support and the cooling bar. Since two counter supports are provided, there are also two such arches, and a centering guide acts on each of these arches, so that the pressure of the sleeve material in the area of the longitudinal sealing seam really presses the material sideways of the longitudinal sealing seam flat onto the flat cooling strip.

If one speaks of the distance between the centering guides, then the cross section is again considered and a line drawn from one centering guide directly to the other. This connecting line of the two centering guides is then parallel to that of the counter supports. The end points of this connecting line between the centering guides are preferably located at the point where the centering guide contacts the outer surface of the clamped sleeve. In cross section it is a point, in the view radially from the inside of the tube wall of the sleeve it is a line. The centering guide does not have to extend over the entire height of the sleeve and therefore not over the entire height of the cassette, because the sleeve held does not have to be touched over every point of its height, although this would not be disadvantageous. For reasons of weight and material savings, however, the centering guide need not extend over the entire height of the cassette, which corresponds approximately to the height of the sleeve to be machined. Nevertheless, the surface of the centering guide facing the interior of the cassette or the sleeve should preferably be flat.

It is also advantageous according to the invention if an opening extending parallel to the longitudinal central axis of the cassette is arranged in the region of a side wall, the cooling strip preferably being diametrically opposite the flat part for attaching the cassette. It is preferred, two adjacent side walls in their - ^• seen in the cross-sectional form over the circumference extending length is only about half with the result that this results in between these two side walls, the described opening, which then thus extends parallel to the cooling bar. The cassette can preferably be left open in the area next to a long side of the cooling strip and the - seen over the circumference - the next edge, which begins in cross-section, for example after 70 ° to 90 °, preferably after 80 °, can begin before the centering guide. Viewed in cross section, the material of the cassette would therefore be missing on the one arch between the centering guide and the cooling strip, so that the opening extending parallel to the longitudinal central axis of the cassette is located here

The advantage of this opening is an undisturbed free movement of holding means that have contact with the sleeve from the outside, specially designed as suction cups holding the sleeve outside and pushing the sleeve axially from the outside into the cassette and from this holding and transport position can also move out of the sleeve again. This opening has a particularly favorable effect when one thinks of the return stroke of the holding means, which can be moved back into the initial position after a sleeve has been pushed completely through the cassette without the sleeve having to be moved away. If one were to think of holding means provided with a piston or the like, one would first have to move the cassette into another position before the return stroke in such a way that the return stroke is not occupied by a cassette. Alternatively, one could certainly not move the cassette laterally, that is to say transversely to its longitudinal central axis, during the return stroke of such a piston slide, because otherwise the piston, which is simultaneously returning, would strike the cassette.

Also preferred is the arrangement of the cooling strip opposite the mentioned first side wall with the flat part on which the cassette e.g. is attached to a conveyor line It has been shown that in such an arrangement, the cooling bar is in an optimal position, easily accessible from the outside and next to the opening, which is also easily accessible from the outside.

It is also expedient if, according to the invention, the distance of the plane through the cooling strip from the connecting line of the two centering guides in the respective contact line with the sleeve on the one hand and the distance of this connecting line between the two centering guides from the connecting line of the two counter supports on the other hand and thirdly half the length of the connecting line of the two counter supports is smaller than the radius of the undeformed, circular sleeve. Of course, the absolute amounts of the distances mentioned depend on the radius of the sleeve to be machined. However, if the above conditions are met, the sleeve can be deformed in an optimal manner, so that the longitudinal seal seam and also its edge regions are pressed flat over the height of the entire longitudinal seal seam onto the sleeve such that good cooling of the longitudinal seal seam is achieved in a short time is guaranteed without having to introduce special coolant to the cooling strip.

In a particularly expedient exemplary embodiment, it has been shown that for a radius = 47 mm of the undeformed sleeve:

the distance of the plane through the cooling strip from the connecting line of the two centering guides (in the respective contact line with the sleeve) = 40.5 mm ± 1 mm, the distance of the connecting line of the two centering guides from the connecting line of the two counter supports = 36 mm ± 1 mm, the length of the connecting line of the two centering guides = 94 mm ± 1 mm, the length of the connecting line of the two counter supports = 90 mm ± 1 mm and preferably the distance between those laid through the cooling strip Level from the respective counter support ■ 66.5 mm ± 1 mm.

If these dimensions are observed for the parts of the cassette described above, the areas of the sleeve to be cooled lie optimally on the cooling strip, and a flat contact of the latter with the seam area of the sleeve is ensured. If the dimensions are significantly exceeded, there is an incorrect deformation of the sleeve during its stay inside the cassette, and after the sleeve has been removed from the cassette after the longitudinal sealing seam has hardened, the cross section of the sleeve can deviate slightly from the circular shape. It is therefore particularly expedient to adhere to the specific dimensions given above in order to avoid any failure or errors that may occur.

It is particularly advantageous if the cooling strip is made of metal, preferably aluminum. This metal is easy to process and also has good thermal conductivity, which is desirable for the absorption and removal of the heat calories absorbed by the longitudinal seal seam

According to the invention, a multiplicity of cassettes can also be provided on a conveyor belt between a sleeve-making machine and a lid and bottom molding machine. Taking into account and observing this feature of the invention, it is then advantageously possible to use a sleeve-making machine which, for example, produces a sleeve made of foamed plastic material per second; and at the same time to use a lid and bottom molding machine which processes six units per six seconds. In other words, the last-mentioned lid and bottom molding machine of this particular embodiment requires a total of six sleeves, which can then be processed for six seconds with the start of treatment at the same time, until the cover and base are then formed on the six sleeves, for example by injection molding. The conveyor line would then be a kind of adaptation unit, because both the described sleeve making machine and the downstream lid and bottom molding machine can work at the same time, the meantime is used to fill the six stations of the lid and bottom molding machine and also to appropriately cool the longitudinal sealing seam. An adaptation to a first machine with a first cycle time is then possible to a second machine with a second cycle time, and at the same time the time of the adaptation is used for cooling, which is also shown in FIG the preferred manner according to the invention.

According to the invention, it is expedient to use the cassette of the type described above for transporting and cooling sleeves made of foamed plastic material and provided with a longitudinal seal seam for the production of packaging for flowable filling goods. The use of the cassette is therefore of particular interest to packaging manufacturers. Packaging for flowable filling goods can be produced very effectively and effectively in this way. Flowable filling goods are liquid goods of various viscosities (volatile liquids, viscous pastes, etc.) as well as free-flowing filling goods or bulk goods. Particularly in the case of liquid packs, particularly high demands must be made of the tightness and strength of seams, so that the use of the cassette according to the invention described here means a favorable further development for the manufacturer

Further advantages, features and possible uses of the present invention result from the following description of preferred embodiments in conjunction with the drawings. Show it:

1 shows in perspective a preferred embodiment of a cassette, into which one looks through the opening, FIG. 2 shows a cross-sectional view of this cassette with the deformed sleeve and dimensions indicated, FIG. 3 shows a representation of another embodiment of FIG

Cassette, also with a drawn-in, held sleeve, and FIG. 4 broken off one end of an endless conveyor strand in the form of a chain with a plurality of chains attached to and rotating with the chain

Cassettes.

The cassette, generally designated 1, serves to accommodate a sleeve 2, which is only shown deformed in the drawings, and which is made of a flexible, foamed plastic, but alternatively can also be made of plastic-coated paper. The cassette 1 has roughly four side walls 3, 4, 5 and 6. A first side wall 4 has a flat part, on which the cassette 1 is attached by means of screws 7 shown in FIGS. 2 and 4 to a conveyor line 8, which can be seen broken off in FIG. 4 as a chain, the first side wall 4 mentioned in each case a chain link is screwed tight. The side wall 6 opposite this first side wall 4 is only half-finished, namely is integrally formed on the side wall 5 at one end and carries a cooling strip 9 at its other end. This cooling strip extends over the entire height H (FIG. 1) of the cassette 1.

In Figure 1, the direction of insertion of a sleeve 2 is shown with the arrow 10, which is why different parts of the cassette 1, including the cooling strip 9, have a beveled or bent insertion part 9 '. The reference number 9 'here designates the bevelled insertion part 9' of the cooling strip 9. This is designed in a strip-like manner and evenly over the rest of the cassette height. In the cross-sectional views of the cassette 1 according to FIGS. 2 to 4, two vertically intersecting dashed lines are shown in the center of the cassette 1 and also the sleeve 2, the crossing point 11 of which is the longitudinal central axis of the cassette 1. It can be seen that the cooling strip 9 extends parallel to this longitudinal center axis 11. Likewise, counter supports 12a and 12b are shown to extend longitudinally almost over the height H of the entire cassette 1, the counter supports 12a, 12b also being bevelled or beveled on the side facing the insertion direction 10. have bent insertion parts 12 '. If one considers the longitudinal central axis 11 as a reference point, then the two counter supports 12a and 12b are located on the other side opposite the cooling strip 9, and in addition the counter supports 12a and 12b are at a distance V _G from one another if one considers the cross section and the two counter supports 12a , 12b connects with a shortest line V _G The shortest connecting line V _{G of} the two counter supports 12a, 12b is shown in dashed lines in FIGS. 2 and 3, and their length is shown on the outside left by a double arrow

The cassette 1 also has two centering guides 13a, 13b, which are arranged on diametrically opposite sides with respect to the longitudinal central axis 11 of the cassette 1, that is to say the centering guide 13a on the side wall 3 and the centering guide 13b on the opposite side wall 5 . The centering guides 13a and 13b also have their beveled, bent insertion parts 13 '.

In Figure 1 it can be seen above that the centering guide 13a in the axial direction, i.e. is shorter in the direction of the longitudinal center axis 11 of the cassette 1 than corresponds to the total height H of the cassette 1. In the lower region of FIG. 1, in the wall 5, the centering guide 13b cannot be seen, but the bevelled insertion part 13 'can.

If we turn to the illustration of FIGS. 2 and 3, ie the cross-sectional view, then the arrangement of the centering guides 13a and 13b can also be described in such a way that they each lie on the arc between the cooling strip 9 and the counter support 12a, which extends over approximately 130 ° or 12b. To be more precise, they are located on the bend approximately in the 90 ° position when one goes out from the cooling strip 9. They are also outside an isosceles triangle, which could be drawn from the points 14a and 14b of the counter supports 12a and 12b to the central contact line 15 (shown in broken lines in FIG. 3).

At the points of contact 15a and 15b, the sleeve 2 deformed in the cassette 1 rests against the two diametrically opposite centering guides 13a and 13b. This connecting line V _{2 of} the two centering guides 13a, 13b runs through the longitudinal center line 11 of the cooling strip 9, which is shown as the center point in FIGS. 2 to 4. The vertical line 16 likewise running through this longitudinal center line 11 is perpendicular to the flat surface 17 ′ of that of the longitudinal center line 11 facing side of the cooling bar 9, through which one can also think a level E placed. This plane E is parallel to the connecting line V _{z of} the two centering guides 13a, 13b and parallel to the connecting line V _{G of} the two counter supports 12a, 12b. The length of the connecting line V _z is shown on the right in FIGS. 2 and 3 with the double arrow, which, like the double arrow shown on the far left, is vertical in the figures.

In FIG. 1, one looks through a large opening 17 onto the first side wall 4 arranged behind and to the left with the flat part, where holes 18 for the passage of the fastening screws 7 can be seen. This opening 17 extends parallel to the longitudinal central axis 11 of the cassette 1. The opening 17 lies in the region of the side walls 3 and 6, half each so to speak. They can also be thought of as being arranged in the region of one side wall 3 or the other side wall 6. In the cross-sectional view of FIGS. 2 and 3, this opening, indicated by the arrow 17, lies in the region of the 90 ° bend between the upper centering guide 13a and the free end edge of the cooling strip 9. With the sleeve 2 inserted, as shown in FIGS. 2 to 4 , This opening 17 is closed by the sleeve 2 held by the cassette 1. It can be seen how holding means can reach the surface of the sleeve 2 from the outside through this opening 17. For example, suction cups are in this way able to hold the sleeve both before and in as well as after passing through the cassette 1, if one considers the transport direction according to arrow 10 (FIG. 1) during the return stroke of these suction cups, not shown, at a radial distance outside the cassette 1, the latter can move further with the conveyor line 8 in the direction of the arrow 19 shown in FIG. 4 transversely to the sliding direction 10 of the sleeve 2. A fault is advantageously eliminated. D denotes the distance between the plane E through the cooling strip 9 from the connecting line V _{z of} the two centering guides 13a, 13b, said connecting line V _z , as said, in the respective contact line 15a, 15b the sleeve 2 lies with c is the distance of the plane E from the two counter supports 12a, 12b. Finally, e is the distance of the connecting line V _z between the two centering guides of the connecting line V _{Q of} the two counter supports 1 a, 12 b.

In the preferred embodiment, the length of the connecting line V _G = 90 mm ± 1 mm represented by the left vertical double arrow in FIGS. 2 and 3. The length of the connecting line V _z shown by the vertical double arrow shown on the right is 94 mm ± 1 mm. This corresponds approximately to the diameter of the undeformed sleeve 2. The distance c between the plane E through the cooling strip 9 and the respective counter support 12a or 12b is 66.5 mm ± 1 mm. The following also applies:

d = 40.5 mm ± 1 mm; e = 36 mm ± 1 mm.

From a sleeve manufacturing machine, not shown, the conveyor line 8 shown as a chain runs intermittently around the deflection wheel 20 in the direction of the curved arrow 19. On the conveyor line 8, a plurality of cassettes 1 is attached, which are conveyed in this way intermittently at a predetermined rate so that, for example, freshly created sleeves 2 are loaded at the top and remain in the conveyor line 8 for several seconds, a six-station station (not shown) of a lid and Fill the bottom molding machine. During this transport time, the longitudinal sealing seam of the sleeve 2, including the edge regions designated LS in FIGS. 2 and 4, lies flat on the flat surface 17 ′ of the cooling strip 9, with the result of intensive heat dissipation. It can thus be loaded sleeves 2 from the cassettes 1 in a lid and bottom molding machine, which are circular in cross-section in the unloaded state and are well suited for the production of packaging for flowable filling goods.

The difference between the embodiment in FIG. 3 and that in FIG. 1 lies in the tubular configuration of the counter supports 12a and 12b and the mounting of the centering guides, the counter supports and the cooling strip by means of a wall which is corrugated in cross-section and which curls the side walls 3 makes up to 6.

Claims

Patent claims

1. Cassette for receiving and holding a sleeve (2) made of flexible, plastic packaging material, with side walls (3 - 6), of which a first (4) has an approximately flat part for attaching the cassette (1) to a conveyor line ( 8), characterized in that a second side wall (6) has a cooling strip (9) extending over the height (H) of the cassette (1) and that on the longitudinal central axis (11) of the cassette (1) opposite the cooling strip (9) located on the side two counter supports (12a, 12b) are provided at a distance (V _G ) from one another.

2. Cassette according to claim 1, characterized in that the connecting line (V _G ) of the two counter supports (12a, 12b) with the central line of contact (15) of the cooling strip (9) spans an isosceles triangle that the middle (11) of Cassette (1) facing surface (17 ') of the cooling strip (9) is flat and the corresponding surfaces of the counter supports (12a, 12b) are curved such that the center of curvature is outside the cassette (1)

3. Cassette according to claim 1 or 2, characterized in that, seen in cross section, on the two arches between the counter support (12a, 12b) and cooling strip (9) outside the isosceles triangle two centering guides (V _z ) from each other ( 13a, 13b) are arranged.

4. Cassette according to one of claims 1 to 3, characterized in that in the region of a side wall (3, 6) an opening (17) extending parallel to the longitudinal central axis (11) of the cassette (1) is arranged, preferably the cooling strip ( 9) diametrically opposite the first side wall (4) with the flat part for attaching the cassette (1).

5. Cassette according to one of claims 1 to 4, characterized in that the distance (d) through the cooling strip (9) layer (E) from the connecting line (V _z ) of the two centering guides (13a, 13b) in the respective Line of contact (15a. 15b) with the sleeve (2) and the distance (e) of this connecting line (V _z ) from the connecting line (V _G ) of the two counter supports (12a, 12b) and half the length of the connecting line (V _G ) each is smaller than the radius (r) of the undeformed, circular sleeve (2).

6. Cassette according to claim 5, characterized in that for a radius (r) = 47 mm of the undeformed sleeve (2) applies:

the distance (d) = 40.5 mm ± 1 mm, the distance (e) - 36 mm ± 1 mm, the length of the connecting line (V _z ) - 94 mm ± 1 mm, the length of the connecting line (V _G ) = 90 mm ± 1 mm and preferably the distance (c) of the plane (E) through the cooling strip (9) from the respective counter support (12a, 12b) = 66.5 mm ± 1 mm.

7. Cassette according to one of claims 1 to 6, characterized in that the cooling strip (9) is made of metal, preferably of aluminum.

8. Cassette according to one of claims 1 to 7, characterized in that a plurality of cassettes (1) on a conveyor line (8) between a sleeve-making machine and a lid and bottom molding machine is provided all round

9. Use of the cassette (1) according to one of claims 1 to 8 for transporting and cooling of existing from foamed plastic material, with a longitudinal sealing seam (LS) provided sleeves (2) for the production of packaging for flowable filling goods.