DE1238757B - Cross-bottom sack, in particular as a valve sack, made of polyethylene or the like. Plastic and process for its production - Google Patents

Description

GERMAN PATENT OFFICE

EDITORIAL B65d

German class: 54 b -4/20

Number: 1 238 757

File number: B 68038 VII b / 54 b

1 238 737 Filing date: July 16, 962

Opened on: April 13, 1967

The invention relates to a cross-bottom sack, in particular as a valve sack, made of polyethylene or similar plastic, and to a method for its production. Cross-bottom sacks, especially those made of paper, have been known for a long time. With such cross bottoms, the bottom is formed starting from a tube section by pulling the tube section ends into a square bottom, triangular or trapezoidal bottom side folds being formed depending on the dimensions. The two bottom-side envelopes are then folded over on the floor and glued on the one hand to the corner folds and on the other hand to one another. In order to reinforce the cross-bottom that has been completed in this respect, it is known to glue a slip of paper that occupies the bottom surface onto the bottom. In addition to this or instead, it is known to increase the part of the bottom area occupied by the bottom side envelopes by folding part of the corner taps of one or both of the bottom side envelopes outwards, with the bottom side envelopes, which still retain a trapezoidal shape, being given a larger area. Further, it is also known for cross bottom paper to form flaps by placing incisions in the corner folds the bottom side of envelopes which can be folded outwards. Such a configuration also gives the bottom side envelopes an enlarged area which, however, without reaching the size of the area of the finished bottom, increases the load-bearing capacity of the bottom.

In the case of the known cross bottoms, the bottom side envelopes usually have the width of the finished floor width less than the width. However, a design is also known in which both Bottom side envelopes are equal to the width of the finished bottom. A bottom envelope is triangular and the other bottom side envelope is formed in the shape of a trapezoid which is one of its own tapering end merges into a rectangle formed by folding open corner parts.

In the formation of cross-bottom bags from plastic film instead of paper, the bottom designs known for paper sacks have essentially been retained. Since the usual gluing causes difficulties with plastic film as a material, weld seams are used in place of the flat glued joints, the application of which is usually associated with considerable effort. For a tight sealing of the bottom, a number of weld seams are required, which once form the cross-bottom sack, in particular as a valve sack,
of polyethylene or the like. Plastic and process for its manufacture

Applicant:

Bischof & Klein, Lengerich (Westphalia)

ίο

Named as inventor:

Alois Gröner, Lengerich (Westphalia)

2

Connect the bottom side envelopes with the corner envelopes and, on the other hand, the bottom side envelopes with one another. Since these sealing welds lie within the bottom surface, it is necessary to take precautions to prevent welding through, which, for. B. can be done by applying paint coatings on the plastic film in the endangered areas or by introducing thermal insulating layers. The application of the weld seams regularly requires an intermittent advancement of the hose sections from one work station to the next work station within the floor laying machines usually used for their production, which considerably reduces their output per unit of time compared to the paper sacks formed and glued in a continuous cycle.
In the known cross-bottom sacks, as a rule, triangular or trapezoidal areas adjoining the bottom transverse edges remain, which are significantly weaker than the bottom areas occupied by the bottom side envelopes. In addition to the weakening of the bottoms in these areas, it can be observed that bottoms designed in this way tend to round when the sacks are filled and consequently do not have an exact box shape.

The invention is now based on the object of providing an exactly box-shaped when filled To create a cross-bottom sack made of plastic that has a high bottom strength with a simple bottom fold has and with the known floor laying machines without any noteworthy additional Effort can be produced quickly and cheaply. For this purpose the cross-bottom sack is according to the invention essentially characterized in that the end of the flat bag tube in such a way

709 549/121

is raised that bottom side envelopes with a corresponding to the width of the later bottom Width are formed that one of the bottom side folds by folding each part outward the corner impacts for the purpose of reshaping the bottom side envelope with the corner impact parts into one The rectangle corresponding to the size of the later floor area is folded over into the plane of the floor area and along the bottom longitudinal edge opposite this bottom side envelope to form a closed one Bottom is welded. The cross-bottom sack according to the invention is characterized by a simple one Folding out, in which only a single bottom-side envelope is involved in the formation of a tightly sealed soil is involved. Despite its simple folding, the floor shows a high level of strength because the entire floor area is taken up by the bottom side envelope. The closure of the bottom by means of only a single edge weld seam running in the longitudinal direction of the bottom eliminates the precautions previously required to prevent welding through, forms a secure, tight bottom seal and, in conjunction with the bottom fold, enables the Sacks on known floor laying machines only with the addition of simple devices continuously and therefore extremely cheap to manufacture. The folded page cover can with its side zones be inserted under the corner notches, which in particular relieves the bottom corner points be, or it can be placed with its edge zones on the corner impacts, creating a results in a completely smooth, closed bottom surface in a rectangular shape. In any case, it is ensured that the When the sack is full, the bottom retains an exactly rectangular shape and so does the sack as a whole conveyed the desired exact box shape. The edge areas of the other, not folded over The bottom cover can be folded again when it is placed on the corner folds, so that this other bottom side envelope also forms a ground-level rectangle. This training increases although slightly the manufacturing effort, but creates a special reinforcement of the Bottom, which can be particularly desirable in the case of large bags filled with heavy goods.

Furthermore, according to the invention, only a narrow edge of the non-folded page envelope for Laying down on the floor can be used and either to reinforce the already existing Serve weld seam on the bottom side edge or take its place. The one corner impact can be advantageous cut on one side in the direction of the side cover fold line and the corner flap after be turned over on the outside, the corner filler being provided with a weld seam along the cutting line is. Instead of this, the one corner fold with two incisions in the direction of the fold lines on the side cover can also be used and the corners of the two side envelopes can be folded out wherein a weld is placed parallel to one of the incisions, which connects the corner with the floor connects and with another incision in the one lying on the other side of the floor center line Page cover is provided perpendicular to this, so that this page cover partially on the ground can be folded over and forms a valve opening together with the fully folded side cover. At un-

changed floor area fully occupied by the bottom side envelope is simpler in both cases Way given the formation of a valve opening. To facilitate the filling and for simultaneous Reinforcement of the valve opening can be a corner impact with two incisions in the direction of the Be provided with side cover fold lines and a flap on the corner fold in the area of the bottom width be welded, which protrudes with its outer end from the valve opening. You can use the a double-width flap should be placed on a corner entry, which is on the one hand with welded seams the corner turn and on the other hand is welded to the one side cover, the weld seam to weld the bottom at the same time the folded flap to a hose valve connects. In this embodiment, a particularly simple formation of a hose valve with a special Resistance to stresses during filling and increased tightness at the same time.

Several embodiments of the subject matter of the invention are illustrated in the drawing. Show it

F i g. 1 to 3 a first embodiment,
F i g. 4 to 6 a second embodiment,
F i g. 7 to 9 a further embodiment,
10 and 11 another embodiment,
FIGS. 12 to 14 show an embodiment,
F i g. 15 to 17 a further embodiment,
18 to 20 a further embodiment,
Fi g. 21 to 23 another embodiment,
F i g. 24 to 27 a further embodiment,
28 to 31 a further embodiment.
In the illustration according to FIG. 1 to 3 is in FIG. 1 shows a sackcloth drawn up in the shape of a cross-bottom. Starting from this, the left bottom flap is unfolded and opened to the length of the bottom. According to FIG. 2, corner 1 is placed under point 2 and corner 3 under point 4. The edge 5 comes into a position marked 6 and the edge 7 into a position marked 8 . The edge 9 moves into the position indicated by 10. The same applies to the lower half of the floor. The outer edge 11 of the left bottom side cover lies on the right side edge 12 of the bottom, and the picture from FIG. 2. The outer bottom side envelope 13 is then cut off and a weld seam is made from point 1, 2 to point 3, 4 . The finished floor then has the shape shown in FIG. 3. Instead of cutting off the bottom side of the envelope 13 it can be also folded onto the ground and is connected thereto, for. B. by a pressure sensitive adhesive or also by welding.

In the embodiment according to FIG. 4 to 6 is again based on a bag tube, the ends of which are drawn up in the shape of a cross base. Starting from this, incisions from points Γ to 2 ' and 3' to 4 ' are made in the outer bottom cover. The corner tab 14 is folded over into the position 15 and the corner tab 16 into the position 17 . Then again, as in the embodiment described above, the inner bottom side envelope is folded over, namely point 18 is folded under point 19 and point 20 under point 21. A weld seam is then placed between points 18, 2 ' and 20, 3' . Finally, the unfolded bottom side envelope 22 is folded over on the floor and with it

attached to this by means of adhesive or welding. The finished floor then results Fig. 6.

In the embodiment according to FIG. 7 is based again on the end of the bag tube pulled up in the shape of a cross-bottom. The left bottom flap is again unfolded in the manner described above. However, point 1 "is placed on point 2" and point 3 " is placed on point 4" . It then gives the image shown in FIG. 8. Then, a weld between the points 1 ', 2' placed and 3 ", 4", and the one designated by 23 outer bottom side envelope is cut off. However, this can also be laid down on the floor here and attached by means of adhesive, welding or the like.

F i g. 10 and 11 show a further modification. The part of the not yet folded over bottom side envelope, which is designated as 24, is cut off, see above

cut, and then a weld is made from point 45 to point 52, 53 , as shown in FIG. 20 illustrates. The lower end forms a valve opening, while the upper end is closed.

In the embodiment according to FIG. 21 to 23 incisions are provided between points 55 and 56 and 57 and 58 . A tab L is placed on the corner entry, the lower end of which protrudes from the valve opening. It is welded to the corner fold along the incisions. The bottom is folded in such a way that point 59 is placed under point 60 . Then the right bottom cover is laid down on the floor by folding out the corner tab 61. Then the left bottom cover is folded over, the point 62 coming to lie with the folding of the corner fold on the point 63 and the side edge 64 of the left bottom cover on the side edge 65 of the bottom.

that an edge strip 25 remains. This will then place 20 dens. The corner tab 66 of the left bottom side

folded down on the floor and by welding, gluing or the like. In this embodiment, the weld seam along the side edge of the base can be omitted. In the embodiment after the envelope has been folded out beforehand. The transverse edge 67 of the left bottom side cover lies on the transverse edge 68 of the folded-out corner tab 61. After the folding, a welding

Fig. 12 to 14 is again based on the 25 seam along the side edges 64, 65 placed, as is

The end of the sack tube pulled up in the shape of a cross-bottom is made in such a way that point 26 is placed under point 27 and point 28 under point 29 . Then F i g. 23 indicates. The two transverse edges 67, 68 lying on top of one another can be connected to one another by a further weld seam 69 . In the embodiment according to FIG. 24 to 27

point 30 becomes point 31 and point 30 is an incision between points 70 and 71

32 placed on the point 33 , whereby the part of the corner fold that lies downwards is folded. 13 shows this in an intermediate stage of the folding. After the folding is complete, it is provided and the corner tab of the right bottom cover is folded out so that point 70 comes to rest on point 72. Then a flap or an insert sheet L is placed, the

14. In this case, 35 is through the weld seam 73 with the corner turn and

the side edge 34 on the side edge 35 of the bottom through the weld 74 with the right bottom

come to rest, and both side edges are connected to the side cover. When folding the bottom

by a weld seam between the points 32, dens comes in the manner described above

33 and 30, 31 welded, as shown in FIG. 14 shows. Point 75 to lie on point 76. It will

In the embodiment of Fig. 15 of the flap 40 is folded. It then becomes a weld

The corner entry from point 36 to point 37 is inserted 77 , and the left bottom side envelope 78 is

cut and cut a weld along the incision. The weld seam 77 turns off

Cut down. The corner flap of the bottom right-hand side of the flap made a closed valve that

The page cover is folded outwards, ie it has the shape of a tube.

the corner 38 comes into position 39. Then according to F i g. 16, the bottom side envelope is folded down onto the floor, the point 41 coming to the point 42 , and a weld seam 40 is laid, which extends the folded bottom side envelope along the length of the. In the embodiment according to FIG. 28 to 30, incisions are provided between points 79 and 80 as well as 81 and 82 and weld seams are made between points 83 and 84 and 85 and 86 . Then the bottom is folded,

The bottom side edge connects to the bottom. The 50 where z. B. after one of the previously described off

The left bottom side envelope 43 can then be cut off or, as in the examples described above, also folded over onto the bottom and fastened there.

In the embodiment according to FIG. 18, the starting point is again the end of the bag tube, which is pulled up in the shape of a cross-bottom. Incisions are provided between points 44 and 45, 46 and 47 and 48 and 49. A weld seam is placed between points 50 and 51 , which connects the corner entry to the floor. Then the corner 52 is placed on the point 53 in accordance with the above. At the lower end of the bottom, the corner tabs 54, 55 will lead out to the outside, the point 87 comes to lie under the point 88. The lower corner tabs of the two bottom side envelopes are folded outwards so that point 79 comes into the position indicated by 89 and point 81 into the position indicated by 90. The weld seams between points 83 and 84 as well as 85 and 86 connect the lower corner entry to the bottom side envelopes, in fact in a larger width than the bottom width. After the right bottom flap 91 has been folded down onto the floor, the left bottom flap is also folded over, the corner flap being folded again at the upper end, as indicated at 92.

The corner 93 lies on top of the corner 94. Then folds and the right bottom page envelope on the 65 with the side edge 95 of the left bottom side envelope, which was previously folded onto the ground, lies on the side edge 96, and both side envelopes are placed. The part 56 of the edge remains in place with a weld seam (FIG. 3) with the left bottom side turn-up and is connected to one another. The overlapping transverse

Claims (15)

Edges 97, 98 of the upper layers of the valve opening can also be connected to one another by a weld seam. When it is mentioned above that a connection is to be made by welding, this is not only to be understood as the usual welding by means of heated tools or by means of high frequency, but also welding in such a way that sealing strips are introduced between the surfaces lying on top of one another glued on, welded on or extruded on. These closure strips can expediently consist of the same material as the sack itself. Welding can also be carried out by means of a welding wedge. Finally, the edges to be connected can also be connected by extruded profiles which overlap the free edges in an approximately U-shape or the like. It is understood that all known or suitable valves, e.g. B. fringed valves or other ao self-sealing valves can be used. Claims: a5 1. Cross-bottom sack, in particular as a valve sack, made of polyethylene or similar plastic, characterized in that the end of the flat sack tube is pulled open in such a way that bottom side envelopes with a width corresponding to the width of the subsequent bottom are formed that one of the bottom side envelopes with outward folding each part of the corner folds for the purpose of reshaping the bottom side cover with the corner turn parts folded over into a rectangle corresponding to the size of the later floor area in the plane of the floor area and along the this bottom side envelope opposite bottom longitudinal edge to a closed bottom is welded. 2. Sack according to claim 1, characterized in that the folded side envelope with its side zones is pushed under the corner notches. 3. Sack according to claim 1, characterized in that the folded side envelope with its edge zones is placed on the corner folds. 4. Sack according to claim 2, characterized in that the edge regions of the other, Unfolded bottom side envelope when placed on the corner folds in itself again are folded, so that this other bottom cover also has a bottom-level rectangle forms. 5. Sack according to one of claims 1 to 3, characterized in that the non-folded Bottom cover is cut off. 6. Sack according to one of claims 1 to 3, characterized in that the non-folded The cover is folded onto the floor and welded or glued to it. 7. Sack according to one of claims 1 to 3, characterized in that only a narrow one Edge of the unfolded cover is used to lie down on the floor and either to reinforce the already existing weld seam on the bottom side edge or takes its place. 8. Sack according to one of claims 1 to 7, characterized in that the one corner impact cut on one side in the direction of the side cover fold line and the corner flap after is turned over on the outside, with the corner impact along the cutting line with a weld seam is provided (see. Fig. 15 to 17). 9. Valve bag according to one of claims 1 to 8, characterized in that the one corner impact is provided with two incisions in the direction of the side cover fold lines and the Corners of the two side envelopes are folded out, being parallel to one of the incisions a weld is placed that connects the corner impact with the floor, and that a Another incision in the cover on the other side of the bottom center line is provided perpendicular to this, so that this page cover can be partially folded over on the floor and together with the fully folded cover it forms a valve opening (Fig. 18 until 20). 10. Sack according to one of claims 1 to 9, characterized in that the one corner impact is provided with two incisions in the direction of the side cover folds and on the Corner impact in the area of the floor width a tab is welded, which with its outer The end protrudes from the valve opening (Figs. 21 to 23). 11. Sack according to claim 10, characterized in that the superposed delimiting edges of the valve opening formed by the side envelopes are welded to one another (at 9). 12. Sack according to one of claims 1 to 11, characterized in that one corner impact a double-width flap is placed on the one hand with the welded seams Corner envelope and on the other hand is welded to the one side envelope, and that the Weld seam to weld the bottom at the same time to the folded flap a hose valve connects (F i g. 24 to 26). 13. Sack according to one of claims 1 to 12, characterized in that a corner impact with incisions parallel to the fold lines of the side covers, but outside the fold lines is provided so that when the bottom is folded up by means of welds on the side flaps fastened corner envelope is folded over at its outer edges (Figs. 28 to 31). 14. A method for producing a sack according to one or more of claims 1, 2, 3, 5, 9, 10, 11 and 12, characterized in that after cutting off the one not folded over Cover the outside edge of the folded cover with the side edge of the bottom is welded. 15. The method according to claim 14, characterized in that the welding by means of a U-shaped profile that encompasses the side edge of the base and is pressed on from an extruder he follows.