Method and device for producing paper or cardboard box lids and/or box bottoms

Abstract

A method and device for producing boxes from paper or cardboard is provided. The boxes include a cut-out shape in the form of the bottom or the lid, with a lateral wall stuck thereto. The lateral wall is formed from a strip having a beginning, an end, and connection tongues are bent by up to 90 C. Then, the beginning of the strip is applied and fixed to the lateral surface of a cylindrical female mold having a cross-section corresponding to the cross-section of the box, by means of a male mold. Then, the female mold is turned. The strip is sucked onto the lateral surface and held in place by means of a vacuum. After an adhesive has been applied to the beginning or end of the strip, the beginning and end of the strip are stuck together. Then, a cut-out shape in the form of the bottom or the lid, which has previously had adhesive applied to the periphery thereof, is pressed onto the connection tongues. Once the adhesive has hardened and the vacuum has been stopped, the finished box can be removed from the female mold.

Claims

1. A device for producing paper or cardboard box lids and/or box bottoms with a lid or bottom blank and a sidewall attached thereto in a fully automated process, the device comprising: a paper or cardboard strip to be shaped into the sidewall of the box to be produced; a rotatable female mold that corresponds to a shape of the sidewall of the box to be produced; a male mold, which is movable in at least one axis; vacuum openings, which are connectable to a vacuum source and in this manner hold the strip against the female mold as the female mold rotates, and are provided in lateral surfaces of the female mold, wherein the male mold has an active surface, which cooperates with the lateral surfaces of the female mold and in this manner brings the strip closer to and places the strip against the vacuum openings of the female mold as the female mold rotates to modify the strip into the box shape, and wherein the male mold is a traveling ram with a face, whose cross section is matched to a recessed section of the female mold.

2. The device according to claim 1, wherein a device is arranged in front of the female mold for the precise feeding of the strip to the female mold.

3. The device according to claim 1, further comprising a device that is configured to bend the connecting tabs and that is configured to be connected upstream of the female mold.

4. The device according to claim 1, further comprising a stop configured to position a beginning of the strip with respect to the female mold.

5. The device according to claim 4, wherein the stop is a light barrier.

6. The device according to claim 1, wherein the vacuum openings in the lateral surfaces of the female mold are divided into groups, and wherein each group is connectable to the vacuum source via a controlled vacuum connection.

7. The device according to claim 1, further comprising suction openings that are arranged in a first base area of the female mold.

8. The device according to claim 1, further comprising pressure sensors arranged in lines from the vacuum source to the female mold.

9. The device according to claim 1, wherein the female mold is attached removably to an axis of rotation, and wherein the axis of rotation is a vacuum rotary feedthrough.

10. The device according to claim 1, wherein adhesive nozzles are provided for applying an adhesive.

11. The device according to claim 1, wherein a guiding edge for the strip is arranged on a second base area of the female mold.

12. The device according to claim 1, wherein the cross section of the face of the male mold corresponds to the base of the recessed section.

13. The device according to claim 1, wherein a shape of the female mold is irregular.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

(2) FIG. 1 shows a lower part of a box with a star shape; and

(3) FIG. 2 shows the elements of a device for producing the star-shaped paper or cardboard boxes according to FIG. 1.

DETAILED DESCRIPTION

(4) FIG. 1 shows purely schematically the bottom part of a paper or cardboard box with a star shape. Box shapes of this type are often used for chocolates. Boxes may also have the shape of a Christmas tree, Santa Claus, an Easter bunny, an Easter egg, an apple, or also a heart. All of these box shapes have in common that they cannot be produced with box erecting devices that are known and have proven to be effective for cubic boxes.

(5) As FIG. 1 shows, the depicted bottom box part has a bottom blank 2 made of paper or cardboard, on which there is a sidewall, having a paper or cardboard strip 1, which is glued to form a ring by means of overlapping at strip beginning 4 and is then glued onto bottom blank 2. Connecting tabs 3 are provided for gluing. It is also possible however to glue strip 1 in a butt-joint manner to base 2. If connecting tabs 3 are not to be visible, a so-called interior mirror 5 (only shown in areas) is glued in.

(6) The apparatus illustrated purely schematically in FIG. 2 for the production of the bottom box part shown in FIG. 1 has a female mold 10 and a male mold 20 as the major components.

(7) Female mold 10 forms the heart of the device. A cylinder is evident whose base area corresponds to box 1, 2 to be produced; therefore it is also star-shaped. Openings 12 are provided in areas in lateral surface 11 of female mold 10. These can be connected to a vacuum source (not shown) via vacuum connections. It is possible in this way to shape strip 1 into a sidewall by means of vacuum at lateral surface 11 of female mold 10 and to fix it in position until bottom blank 2 is glued on. A guide edge 15 guarantees the exact position of strip 1 along female mold 10.

(8) The production of a matching box lid occurs basically in the same manner. Nevertheless, a female mold with matching dimensions must be used. Therefore, it is of great advantage that female molds 10 can be quickly replaced.

(9) To be able to detect whether strip 1 lies correctly on lateral surface 11 and closes openings 12, pressure sensors can be inserted into the vacuum lines. If the nozzles suck in air, the low pressure in the line drops, which is detected by the pressure sensors and reported.

(10) As can be seen in FIG. 2, strip 1 with already folded down connecting tabs 3 is pushed forward until strip beginning 4 encounters a stop 30. Male mold 20 then travels downward and positions strip beginning 4 precisely in one of the recessed sections of the star-shaped female mold 10. There, strip beginning 4 is held in place by a vacuum nozzle.

(11) Next, female mold 10 is turned with the help of its connecting axis 14, to which it is attached replaceably. In so doing, strip 1 is wound onto lateral surface 11 and shaped. If necessary, the winding and shaping are supported by male mold 20 traveling back and forth in a controlled manner.

(12) As soon as strip 1 has been wound totally onto female mold 10, the end of the strip is pressed against strip beginning 4 with the help of male mold 20, until the previously applied adhesive has hardened. It is basically possible to apply the adhesive as a continuous bead to bottom blank 2 and/or interior mirror 5. It is substantially better, however, when the adhesive is applied precisely metered in a punctiform manner to the front and/or back side of connecting tabs 3; however, because of the plurality of connecting tabs 3 and the high working speed of modern machines, this imposes high requirements on hardware and software.

(13) Next, a bottom blank (not shown) can be removed from a tray in a manner known per se with the aid of a vacuum arm. Said bottom blank is now pressed with the help of the arm onto female mold 10, connecting tabs 3, and strip 1, forming the sidewall, until the previously applied adhesive has hardened. Next, the completed box is removed from female mold 10 with the help of the same or different vacuum arm, whereby the removal process is supported in that air is blown out of vacuum nozzles 12, 13.

(14) Vacuum nozzles 13 provided in the base of female mold 10 have the task of holding in place interior mirror 5, which is placed on female mold 10, before strip 1 has been wound onto lateral surface 11.

(15) The supplying of the vacuum to vacuum nozzles 12, 13 occurs through a vacuum rotary feedthrough integrated into the axis of rotation 14.

(16) The trays, which stock the blanks for the sidewall, bottom, and interior mirror, are not shown in the drawing. The devices that remove the blanks from the trays and supply them to the processing stations are likewise not shown. The vacuum source is also not shown. These functional elements are realized by conventional technology. Their illustration would make the drawing unclear and thereby incomprehensible.

(17) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.