METHOD AND APPARATUS FOR MANUFACTURING A SLEEVE- OR BAG-LIKE CONTAINER, AS WELL AS SUCH CONTAINER

Abstract: In a method of manufacturing sleeve- or bag-like containers (27) two superimposed bands of material (3, 4) are cut transversely into separate container parts which are connected to each other at the cut edge as formed. According to the invention the bands of material (3, 4 ) prior to cutting them into separate containers, are separated at least at one longitudinal edge, whereafter at least one of these longitudinal edges of the bands of material is machined. An apparatus for manufacturing said sleeve- or bag-like containers (27) using this method comprises means (2) for supplying the two superimposed bands of material (3, 4) and a cutting and connecting device (21) extending across the bands of material (3, 4) for separating container parts from the bands of material and connecting them into a container (27). A separating body (6) separates the bands of material (3, 4) at least at one longitudinal edge, and at least a machining device (7-10) on one side of the separating body (6) is adapted to machine the longitudinal edge of the respective band of material (3, 4).

Description: The invention relates to a method of manufacturing sleeve-like containers, wherein two superimposed bands of material lying one above the other are cut transversely into separate container parts which are connected to each other at the cut edges as formed. In a known method of this type which is used for manufacturing sleeve-like containers for flower bunches known as flower sleeves, the bands of material are arranged with respect to each other in transverse direction such that one container part protrudes beyond the other container part on the opening side. The protruding portion or the extension of the one container part is thereafter perforated along a line thereby creating a tear line defining the opening edge of the respective container part. A plurality of containers is then connected at the extensions thereof. When the containers are to be provided around the bunches of cut flowers, a stack of containers is clamped at the extensions and the containers are teared off one-by-one along the tear line. When it is desired to have containers of which the opening edges are machined, for instance cut as an ornamental edge, a stack of containers connected at the extensions is cut off below the tear line in a separate apparatus. Then there is provided a stack of loose containers difficult to handle when the containers are arranged around the bunches of cut flowers. DE-A-2501375 discloses a method and apparatus for manufacturing sleeve-like containers and is used as starting point for claims 1, 6 and 10. In the method according to this document the upper band of material is narrower than the lower band. Only the laterally protruding portions of the lower band are machined to form a flap which, in the final container, is adapted to be folded over the wide opening of the container. It is an object of the present invention to provide a method and apparatus for manufacturing tapered sleeve-like containers, which offer more possibilities to shape the opening edges of the container. For this purpose the method and apparatus have the features of the characterizing portions of claims 1 and 6, respectively. Further embodimens of this method and apparatus are defined in claims 2-5 and 7-9, respectively. The invention provides a reliable apparatus and method with which the opening edges of the container can be shaped to any configuration independent of each other. The sleeve-like container according to the invention, which could be manufactured by the method and apparatus as described, is characterized in that the opening edges have a non-linear shape substantially the whole length thereof, while the container part having the protruding opening edge is connected at substantially this whole opening edge to an extension by means of tear portions forming a tear line extending substantially along the whole protruding opening edge and at a distance from the other opening edge. On the one hand, it is possible to provide such a container with an attractive appearance due to the machined opening edges, while on the other hand the extension of the one container part connected by tear portions and the shorter length up to the opening edge of the other container portion effect a very easy handling of the container when it is to be arranged around the product to be packed. Then it is possible to clamp the containers at their extension as a bundle, as is know per se, and to easily grip the free hanging opening edge by hand since the respective container part is shorter. The invention will hereafter be elucidated with reference to the drawing showing an embodiment of the invention by way of example. Fig. 1 is a very schematic side view of a portion of an apparatus for manufacturing sleeve-like containers. Fig. 2 is a very schematic plan view of the apparatus of fig. 1, wherein several parts of fig. 1 are omitted for the sake of clarity. Fig. 3 is a plan view of a container according to the invention, on an enlarged scale. The drawing shows an embodiment of an apparatus for manufacturing sleeve-like containers, in particular flower sleeves for packing bunches of cut flowers, by way of example. The apparatus comprises a frame 1 that is shown only very schematically and partially, and means for supplying two superimposed bands of material 3 and 4 from one or more rollers not shown, said means being supported by the frame 1 and being indicated only by a roller 2. In the embodiment illustrated by way of example, the bands of material 3 and 4 consist of the longitudinal parts of a single band of material folded double about a longitudinal axis, said longitudinal parts of the wider band of material being cut loose from each other by a knife 5. Of course, it is also possible to supply two separate bands of material 3 and 4, and in the case of bag-like containers the longitudinal parts of the double-folded wider band of material may remain connected to each other along the folding line. The embodiment of the double-folded and cut-open single wide band of material has the advantage that the resulting bands of material always remain in a proper interrelationship in longitudinal direction and cannot drift with respect to each other, without requiring additional measures. This is particularly favourable with printed bands of material, wherein the printings of both bands of material 3 and 4 should have a fixed interrelationship. In the embodiment shown by way of example, the single wide band of material is folded and cut-open by the knife 5 in such a way that the resulting lower band of material 4 is slightly wider than the upper band of material 3 and both of its longitudinal edges project a substantially equal distance outside the upper band of material 3. Of course, the bands of material 3 and 4 may also have equal widths. Drive means not shown effect a step-wise equal supply of both bands of material 3 and 4. The frame 1 of the apparatus supports a horizontal separating plate 6 on its longitudinal sides protruding outside of the bands of material 3 and 4. This separating plate 6 serves for temporary separating both bands of material 3 and 4, for which purpose the upper band of material 3 is guided over the separating plate 6, while the lower band of material 4 is passed under the separating plate 6. After having passed the separating plate 6, both bands of material 3 and 4 merge again. At both opposite longitudinal edges of the bands of material 3 and 4 there is arranged a cutting device 7 and 9, and 8 and 10, respectively above and below the separating plate 6. The cutting devices 7-10 are each provided with an electrically heated cutting die 11, 12, 13 and 14, respectively adapted to move up and down by means of a hydraulic or pneumatic cylinder 15 fixed to the frame 1 in order to press the cutting die against the separating plate 6 for performing the cutting operation. The cutting dies 11 and 13 of the cutting devices 7 and 9 arranged above the separating plate 6 have a curved corrugated central area and two adjoining straight end areas extending more outwardly. These cutting dies 11 and 13 are arranged to effect an uninterrupted cut. The cutting dies 12 and 14 of the lower cutting devices 8 and 10 only have the curved corrugated central area, while the cutting face of these cutting dies is provided with notches 16 interrupting the cut caused by these cutting dies 12 and 14. Furthermore, the cutting die 12, 14 of the lower cutting devices 8, 10 are off-set a small distance transverse to the bands of material 3 and 4 with respect to the cutting die 11, 14 of the respective upper cutting devices 7, 9 that are arranged symmetrically in longitudinal direction of the bands of material 3 and 4. The cutting devices 7 and 8, however, are off-set a distance forwardly in the direction of supply with respect to the cutting devices 9 and 10 at the opposite longitudinal edge of the bands of material 3 and 4. In the neighbourhood of the rear end area of the cutting dies 11 and 13 of the upper cutting devices 7 and 9 there is journalled a transverse guide roller 17, 18, respectively adjacent the separating plate 6, and above each guide roller 17, 18 there is suspended a winding device 19, 20 for winding the continuous edge strips of the upper band of material 3 cut off by the respective cutting dies 11 and 13. Alternatively, it is possible to construct the cutting dies 11, 13 such - amongst others shorter without the straight end portions - that no continuous edge strip is cut off at the longitudinal edges of the upper band of material 3, but loose pieces are cut out. These loose pieces may be discharged by means of gripping means such as clips gripping the pieces before or after cutting, whereafter the clips are brought above collecting or discharging means by displacement means where the clips are being opened so that the pieces of material are released and fall down. It is also possible to exhaust the pieces. At a distance behind the separating plate 6, as seen in the direction of supply of the bands of material 3 and 4, is a die-cutting and sealing device 21 cutting the separate container parts from the bands of material 3 and 4 and simultaneously connecting the facing container parts together at their cut edges by means of sealing. The die-cutting and sealing device 21 consists of two die-cutting and sealing means 22 and 23 extending across the bands of material 3 and 4 and above them and being arranged at a distance from each other, and of co-operating beams 24 and 25 lying under the bands of material. The die-cutting and sealing means 22 and 23 are adapted to move up and down and to be pressed against the respective beam 24, 25 by means of hydraulic or pneumatic cylinders 26 attached to the frame. Both die-cutting and sealing means 22 and 23 are arranged and formed symmetrically to an intermediate transverse plane, and each die-cutting and sealing means 22, 23 itself is constructed symmetrically with respect to its center. The method to be carried out with the apparatus as described and shown is as follows. A wide double-folded band of material is supplied step-wise via the roller 2 and is cut into a lower band of material 4 and a slightly narrower upper band of material 3 by means of the knife. Subsequently, the lower band of material 4 and the upper band of material 3 are passed under and over the separating plate 6, respectively. In a stand-still period of the bands of material 3 and 4 the cutting-dies 11-14 of all cutting devices 7-10 are moved and pressed against the respective side of the separating plate 6 by means of the respective cylinder 15. When using a plastic foil as container material the cutting dies 11-14 will preferably be heated electrically, so that a cut in the bands of material is formed in a very reliable manner. The upper cutting dies 11 and 13 completely cut off an edge strip indicated by a slanting hatching, while the lower cutting dies 12 and 14 only provide an interrupted cut without cutting-off the adjacent edge strip. In this way the opening edges of two oppositely directed containers are cut. After die-cutting the bands of material 3 and 4 are conveyed a distance A further, whereafter the die-cutting operation is repeated. Said distance A is slightly less than the length of the cutting dies 11 and 13 of the upper cutting devices 7 and 9 so that adjacent cuts made by these cutting dies 11 and 13 are slightly overlapping and therefore effect a continuous cut-off edge strip on both longitudinal edges of the upper band of material 3. These edge strips may be passed around the respective guide rollers 17, 18 upwardly to the winding devices 19 and 20 where the edge strips are wound into a coil. In the die-cutting and sealing device 21 the bands of material 3 and 4 machined at their longitudinal edges are cut across into separate container parts, while the respective container parts are directly connected at their cut edges by sealing. In fig. 1, on the left side, the finally cut upper band of material 3 is indicated by horizontal hatching, while the vertical hatching illustrates the outwardly projecting portions of the lower band of material 4. In this way, each cutting and sealing operation produces two separate oppositely directed containers 27 which are gathered and discharged in a known manner not shown. It would also be possible according to the invention to omit the cutting dies 12 and 14 of the apparatus and to machine only the band of material 3 by means of the cutting dies 11 and/or 13 whereafter a stack of containers 27 is formed in or after the die-cutting and sealing device 21 and the tear line 31 is formed and all containers 27 simultaneously in a separate or a joining device. The apparatus according to the invention is then only used to make a cut into one of the bands of material lying inward of-the lateral borders of the other band of material. Fig. 3 shows on a larger scale the container 27 obtained by the method described, in this example the container is a so-called flower sleeve 4 packing a bunch of cut flowers. The container 27 as shown consists of a first lower container part 28 and a second upper container part 29, these container parts being connected to each other at their edges 30, for instance by sealing in the case of a plastic container. Both container parts 28 and 29 taper from a wide corrugatfd opening edge 31, 32 respectively to a narrow end 33. The container parts are not connected to each other at the narrow end 33. The first container part 28 protrudes with its opening edge 31 beyond the opening edge 32 of the second container part 29, for instance a few millimetres. Furthermore the opening edge 31 of the first container part 28 is connected by tear portions 34 to an extension 35 serving for connecting and suspending a plurality of containers. When the container 27 is to be provided around the product, such as a bunch of flowers, the container 27 is teared loose from the extension 35 thereby producing the final usefull configuration of the container. The invention is not restricted to the embodiment described herein before and shown in the drawing by way of example, which can be varied in different manners within the scope of the invention which is defined by the appended claims. It is for instance possible to use the disclosed method and apparatus to manufacture pot-plant sleeves or bags.

Claims: 1. Method of manufacturing sleeve-like containers (27) which taper from a wide opening to a narrow end wherein two superimposed bands of plastic material (3, 4) are supplied simultaneously and step-wise while the longitudinal edges of at least one band of material (3) are machined by die-cutting, whereafter the superimposed bands of material (3, 4) are cut transversely into separate container parts (28, 29) such that successive containers (27) are formed with the opening edge at opposite longitudinal edges of the bands of material, the separate container parts (28, 29) being connected at the cut edges (30) as formed, characterized in that the bands of material (3, 4), prior to cutting them into single containers (27) are separated from each other at both longitudinal edges, whereafter at least one band of material (3) is machined by heat die-cutting at both longitudinal edges such that one opening edge (32) of each container (27) is formed according to an ornamental line substantially along the whole length thereof. 2. Method according to claim 1, wherein both bands of material (3, 4) are machined by heat die-cutting while they are separated from each other. 3. Method according to claim 1, wherein a plurality of single containers (27) is stacked and the stack as formed is cut at a position beyond the first formed opening edge (32) into a second opening edge (31). 4. Method according to claim 2 or 3, wherein the longitudinal edge of one band of material (3) is cut off completely up to the opening edge (32) of the respective container part (29), while the longitudinal edge of the other band of material (4) remains connected to the opening edge (31) of the other container part (28) by a formed tear line (34). 5. Method according to one of the proceding claims, characterized in that the two bands of material (3, 4) are formed by double-folding a single band of material about a longitudinal folding line and by making, prior to machining the longitudinal edges, a continuous cut in the neighbourhood of the folding line for forming the separate bands of material (3, 4). 6. Apparatus for manufacturing sleeve-like containers (27) which taper from a wide opening to a narrow end, comprising means (2) for supplying two superimposed bands of plastic material (3, 4) simultaneously and step-wise, cutting devices (7, 9) having cutting dies (11, 13) to cut the longitudinal edges of one band of material (3), cutting and connection means (22, 23) extending across the bands of material (3, 4) for cutting container parts (28, 29) from the bands of material (3, 4) and connecting them into a container (28), characterized by a separating body (6) for separating the bands of material (3, 4) at both longitudinal edges thereof, the cutting dies (11, 13) being provided at least on one side of the separating body (6) and being adapted to cut substantially one whole opening edge (32) of each container (28) from one band of material (3), and the cutting dies being heated electrically. 7. Apparatus according to claim 6, wherein the separating body (6) is a substantially flat separating plate on both sides of which the bands of material (3, 4) can be guided. 8. Apparatus according to claim 6 or 7, wherein on either side of the separating body (6) there is arranged a cutting device (7, 9; 8, 10) for cutting the longitudinal edge of the respective band of material (3, 4). 9. Apparatus according to claim 8, wherein the cutting dies (11, 13) on one side of the separating body (7) are adapted to make an uninterrupted cut, and the other cutting dies (12, 14) are adapted to make an interrupted cut. 10. Sleeve-like container (27), manufactured of sheet-like container parts (28, 29) connected at least at two edges (30) and each having wide opening edges (31, 32) of which one opening edge (31) protrudes beyond the other opening edge (32) at least in the central area thereof, characterized in that the opening edges (31, 32) have a non-linear shape substantially the whole length thereof, while the container part (28) having the protruding opening edge (31) is connected at substantially this whole opening edge (31) to an extension (35) by means of tear portions (34) forming a tear line extending substantially along the whole protruding opening edge (31) and at a distance from the other opening edge (32).

Inventors: DE KLERK,JOHANNES MARINUS,, DUIVENVOORDEN, JOHANNES FRANCISCUS CHRISTIANUS,
Applicants: KLERK'S PLASTIC INDUSTRIE B.V.
Application year: 1989
Main classification: B31B25
IPC codes: B31B25