NL2004243A

NL2004243A - Method for folding corner of box for packing welding wire.

Info

Publication number: NL2004243A
Application number: NL2004243A
Authority: NL
Inventors: Takuo Hirakawa
Original assignee: Kobe Seiko Sho Kobe Steel Kk
Priority date: 2009-02-18
Filing date: 2010-02-15
Publication date: 2010-08-19
Also published as: JP2010188606A; CN101823350A; KR20100094412A; NL2004243C2; KR101154737B1

Description

METHOD FOR FOLDING CORNER OF BOX FOR PACKING WELDING WIRE

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for folding a corner of a packing box, and more specifically, it relates to a method for pressing a corner of a box for packing a welding wire such as a flux-cored welding wire to form a depression for ease of carrying.

2. Description of the Related Art A flux-cored welding wire (flux-cored wire, also referred to as FCW) that is a tubular steel envelope filled with flux is widely used as a wire for fully automatic or semiautomatic arc welding such as CO2 gas shielded arc welding or MIG welding. There are two types of FCWs: a seamed type having a seam in the hoop, and a seamless type having no seam. The seamless type is expensive to manufacture, and therefore the seamed FCW is widely used.

The seamed FCW means a welding wire having a seam that is closed without being joined, for example, by welding.

A drawn wire having a small diameter of 0.8 to 1.6 mm is widely used as such a flux-cored welding wire. The welding wire is usually wound into a form of a cylinder around a coil core (spool) when manufactured, transported, and used. During the period when the coiled welding wire is moved from a manufacturing factory to a product warehouse, stored in the warehouse, shipped, transported, and delivered to a user, the welding wire is packed in a rectangular parallelepiped corrugated fiberboard box. That is to say, the coiled welding wire is carried in the rectangular parallelepiped corrugated fiberboard box.

However, the welding wire is very heavy, weighing for example 20 kg a roll. This heavy material is packed in a corrugated fiberboard box, for example, 28 cm long, 28 cm wide, and 11 cm high.

When carrying the welding wire, a worker first tilts a corrugated fiberboard box containing the welding wire, inserts one hand between one edge of the bottom of the box and the floor and then inserts the other hand between the other edge of the bottom of the box and the floor. After the insertion of the hands, the worker lifts and carries the corrugated fiberboard box to a predetermined position.

However, it is not easy to lift such a heavy object in an unstable position, and the transportation of the object is also hard work. When lifting the product, the worker may strain their low back. When carrying the product, the worker may drop the product from their hands onto their foot. In particular, since the worker usually wears gloves, the corrugated fiberboard box made of paper is liable to slip.

If handled carelessly, the product may drop onto the foot and damage the foot.

There is proposed a packing box in which a pair of folding lines parallel to a ridge line of the box are provided in the middle of the ridge line, cutting lines connecting the ends of the folding lines to each other are provided, and a depression is thereby provided in the middle of the ridge line (Japanese Unexamined Patent Application Publication No. 3-14449). A worker can carry the packing box with their hand in this depression. However, this depression is low in strength because it is formed by cutting part of the box. In addition, providing the box with the depression forms openings and therefore results in imperfect packing.

A corrugated fiberboard packing box that overcomes such shortcomings of a box for packing a welding wire is proposed, for example, in Japanese Unexamined Patent Application Publication No. 5-262346. The proposed packing box is a corrugated fiberboard box formed substantially by six sides, and it has at least two depressions provided at a corner where three ridge lines meet. Each depression is formed by folding inward on three folding lines that connect the ridge lines to each other.

The corrugated fiberboard packing box will be described with reference to the accompanying drawings. FIG. 4 is a perspective view from above of a packing box having depressions at corners. FIG. 5 is a perspective view from below of the same. FIG. 6 is a front view; FIG. 7 is a bottom view; and FIG. 8 is a development view. The box 1 is made, for example, of corrugated fiberboard and has a rectangular parallelepiped shape. The box 1 is folded inward at four corners of the bottom thereof to form depressions 2.

As shown in the development view of a corrugated fiberboard blank of FIG. 8, the corrugated fiberboard blank for a packing box has a corrugated fiberboard bottom portion 3, a corrugated fiberboard top portion 4, a corrugated fiberboard front portion 10, a corrugated fiberboard back portion 11, and corrugated fiberboard side portions 5 and 6, and further has gluing tabs 7, 8, 9, 12, 13, 14 and 15. The corrugated fiberboard blank is provided with folding lines 16 for folding these portions substantially at a right angle.

By folding the corrugated fiberboard blank of FIG. 8 on the folding lines 16, a rectangular parallelepiped packing box 1. By putting a welding wire in the box and gluing the gluing tabs 7 to 9 and 12 to 15, packing of a welding wire in the corrugated fiberboard packing box 1 is completed.

In the development view of the corrugated fiberboard blank of FIG. 8, folding lines 17 are provided at the four corners of the corrugated fiberboard bottom portion 3. The folding lines 17 serve as ridge lines of the depressions 2 at the corners of the corrugated fiberboard packing box 1.

In the corrugated fiberboard packing box 1 configured as above, first, the blank developed as shown in FIG. 8 is bent substantially at a right angle on the folding lines 16 to shape a rectangular parallelepiped. In the process of folding on the folding lines 16, folding is performed on the folding lines 17. Thus, as shown in FIGS. 5 to 8, the corrugated fiberboard packing box 1 having the depressions 2 is constructed.

The corrugated fiberboard packing box 1 that is constructed as above and in which a welding wire is packed has the depressions 2 at the four corners thereof.

Therefore, when the box is placed on the floor of a factory or a warehouse, there is a clearance between each depression 2 and the floor. The worker lifts the box 1 with their hands in the depressions 2 and their fingers in the depressions 2.

Since the depressions 2 are provided at corners of the box 1, it is unnecessary to tilt the box 1 to insert the hand into the clearance. The worker only has to insert their hands into the depressions 2 and therefore can easily lift the box 1. In addition, since the worker can carry the box 1 with their fingers in the depressions 2, the worker will not drop the box 1 from their hands. Therefore, the safety during carrying can be dramatically improved, and in addition, the portability can be improved. The depressions 2 are not formed by cutting off the corners but provided by pressing the corners into the box, and therefore have high strength.

As described above, the corrugated fiberboard packing box 1 having the depressions 2 at the corners thereof is very easy to carry. However, unlike forming the depressions 2 by manually folding on the folding lines 17 while folding a blank for a packing box into a hexahedral rectangular parallelepiped, folding a blank for a packing box into a rectangular parallelepiped and thereafter pressing the corners thereof into the box mechanically, that is, in an automated process is difficult because the corners are triangular-pyramidally convex.

That is to say, as shown in FIG. 8, for example, in a triangle OAB formed by a folding line 17b and two ridge lines, the sum of the lengths of segments OA and OB is of course larger than the length of section AB. The same is true in the other three triangles. Therefore, great force is necessary to press the triangular pyramidal portion formed by folding lines 17a, 17b, 17c, and 17d and ridge lines OA, OB, and OC into the box. Therefore, if the corner portion is pressed with a stick-like pressing member, the reaction force from the corner portion is great, and for example, the apex of the triangular pyramid is collapsed, or a hole is made.

Japanese Examined Patent Application Publication No. 7-115431 proposes a method for folding a corner of a packing box. By the method, using an improved pressing member, depressions can be easily formed at the corners of a corrugated fiberboard packing box 1, and packing boxes having depressions can be mass-produced in an automated process. In this method, folding lines are preliminarily formed at one or more of the eight corners where three ridge lines meets of a corrugated fiberboard packing box 1 formed substantially by six sides, the folding lines connecting the three ridge lines to each other. The corners provided with the folding lines are pressed into the box to form depressions with a pressing member that moves in a circular arc locus.

The pressing member (pressing apparatus) according to an embodiment of Japanese Examined Patent Application Publication No. 7-115431 is shown in FIGS. 9 and 10. FIG. 9 is a side view. FIG. 10 is a schematic diagram showing the operation thereof. For example, four pressing apparatuses are disposed for four corners of a packing box. In each pressing apparatus, a base 120 is fixed. To the top of the base 120, a supporting member 121 is fixed that supports a cylinder 123. The supporting member 121 is provided with a rocking shaft 122. The axial direction of the rocking shaft 122 is horizontal. The cylinder 123 is supported at its front end by the rocking shaft 122 so as to be able to rock about the horizontal axis. A piston 124 of the cylinder 123 is driven, for example, by oil pressure and can be thrust forward and retracted into the cylinder.

However, a rocking-type pressing member (pressing apparatus) using a rocking shaft 122 such as that of Japanese Examined Patent Application Publication No. 7-115431 has a complex mechanism and is liable to be large in size. Therefore, a relatively large installation space is necessary for performing the method (process) of folding corners of a packing box.

SUMMARY OF THE INVENTION

The present invention is made in consideration of the above-described circumstances, and an object of the present invention is to make it possible to easily form a depression at a corner of a packing box using a pressing apparatus that has a simple mechanism and that can be reduced in size.

In an aspect of the present invention, a folding method for forming a depression for handling at a selected corner of a corrugated fiberboard box for packing a welding wire, includes the steps of: preliminarily forming folding lines serving as ridge lines of the depression in a part of a corrugated fiberboard blank corresponding to the corner where the depression is formed; forming the corrugated fiberboard blank provided with the folding lines into a box shape; and inwardly pressing the corner of the corrugated fiberboard box with a pressing apparatus to form the depression. The pressing apparatus is a fluid cylinder provided with a pressing tip having a shape corresponding to the shape of the depression.

It is preferable that the corner of the corrugated fiberboard box be pressed with the pressing apparatus to form the depression after putting a welding wire in the corrugated fiberboard box formed into a box shape. It is preferable that the corrugated fiberboard box formed into a box shape be placed on and secured to a worktable, and then the fluid cylinder disposed so as to face the corner of the corrugated fiberboard box be operated to form the depression.

The pressing tip may have such a shape that three flanges are disposed around the central axis of the fluid cylinder at regular angular intervals of 120 degrees outwardly in a radial fashion.

The present invention makes it possible to easily form a depression at a corner of a corrugated fiberboard packing box using a pressing apparatus that has a simple mechanism and that can be reduced in size.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C show pressing apparatuses used in a method for folding corners of a packing box according to an embodiment of the present invention, FIG. 1A is a plan view, FIG. IB is a front view, and FIG. 1C is a side view; FIG. 2 is an enlarged perspective view showing only the pressing tip of each of the pressing apparatuses of FIGS. 1A to 1C; FIGS. 3A to 3C show a corner of a corrugated fiberboard packing box, FIG. 3A is a perspective view before folding the corner, FIG. 3B is a perspective view after folding the corner, and FIG. 3C is a sectional view after folding the corner; FIG. 4 is a perspective view from above of a corrugated fiberboard packing box having depressions at corners; FIG. 5 is a perspective view from below of the corrugated fiberboard packing box of FIG. 4; FIG. 6 is a front view of FIG. 4; FIG. 7 is a bottom view of FIG. 4; FIG. 8 is a development view of the corrugated fiberboard packing box of FIG. 4; FIG. 9 is a side view of a conventional pressing apparatus; and FIG. 10 shows the operation of the pressing apparatus of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Preconditions)

The folding method of the present invention is based on the premise that how an object of corner folding, i.e., a corrugated fiberboard box for packing a welding wire is constructed, the structure of a corrugated fiberboard blank for constructing the box, how folding lines are drawn, and the like are the same as those disclosed in the Japanese Unexamined Patent Application Publication No. 5-262346 and Japanese Examined Patent Application Publication No. 7-115431. That is to say, as shown in FIGS. 3A to 3C and 4 to 7, a corrugated fiberboard packing box 1 has at least two depressions 2 provided at corners where three ridge lines 17 meet. Each depression 2 is formed by inwardly folding on three folding lines that connect the ridge lines 17 to each other. Thus, the box is formed into a rectangular parallelepiped shape. More specifically, the corrugated fiberboard packing box 1 is folded inward at four corners of the bottom thereof to form depressions 2. Each depression 2 is formed in such a shape that after obliquely cutting a corner of the rectangular parallelepiped box 1 with a plane and removing a right triangular pyramid, a triangular pyramidal depression the base of which corresponds to the resulting oblique plane is formed.

As shown in the development view of a corrugated fiberboard blank for constructing the box of FIG. 8, the corrugated fiberboard blank has a corrugated fiberboard bottom portion 3 serving as the bottom of the box, a corrugated fiberboard top portion 4 serving as the top, a corrugated fiberboard front portion 10 serving as the front, a corrugated fiberboard back portion 11 serving as the back, and corrugated fiberboard side portions 5 and 6 serving as the sides. The corrugated fiberboard blank further has gluing tabs 7, 8, 9, 12, 13, 14 and 15 necessary for gluing. The corrugated fiberboard blank is provided with folding lines 16 for folding these portions substantially at a right angle.

By folding the corrugated fiberboard blank of FIG. 8 on the folding lines 16, a rectangular parallelepiped packing box 1. By putting a welding wire in the box and gluing the gluing tabs 7 to 9 and 12 to 15, packing of a welding wire in the corrugated fiberboard packing box 1 is completed. Therefore, the folding lines 16 serve as ridge lines of the corrugated fiberboard packing box 1.

In the development view of the corrugated fiberboard blank of FIG. 8, folding lines 17 are provided at the four corners of the corrugated fiberboard bottom portion 3. The folding lines 17 include segments 17a provided in the corrugated fiberboard front portion 10 or back portion 11, segments 17b provided in the corrugated fiberboard bottom portion 3, segments 17c provided in the corrugated fiberboard side portions 5 and 6, and segments 17d provided in the gluing tabs 12 to 15.

Provided that the length of one side of the top and bottom of the corrugated fiberboard packing box is 250 to 300 mm, the length of the sides OA and OB of triangular parts formed by the folding lines 17a to 17d and the folding lines 16 is for example 60 to 70 mm, the length of the side OC is for example 30 to 40 mm, the length of the side OD is for example 60 to 70 mm, and the length of the side OE is 30 to 40 mm. The folding lines 17 are provided in a position where three folding lines 16 serving as ridge lines of the corrugated fiberboard packing box 1 meet, so as to connect the folding lines 16 to each other.

The folding lines 16 and 17 can be formed, for example, by pressing as in the conventional methods. The folding lines may be perforated lines or may be provided with a cutting die that cuts to half the depth of the thickness.

In the corrugated fiberboard packing box 1 configured as above, first, the blank developed as shown in FIG. 8 is bent substantially at a right angle on the folding lines 16 to shape a rectangular parallelepiped. In the process of folding on the folding lines 16, folding is performed on the folding lines 17 while pressing the part around the point 0 into the box so that the point 0 is located inside the rectangular parallelepiped. Thus, as shown in FIGS. 5 to 8, the packing box 1 having the depressions 2 is constructed. The folding lines of each depression 2 are provided so as to connect three ridge lines.

The worker opens the top portion 4 and puts a welding wire (not shown) wound around a coil core in the corrugated fiberboard packing box 1. The coiled welding wire is placed with its axis perpendicular to the top and bottom of the corrugated fiberboard packing box 1. Although the depressions 2 at the four corners of the bottom of the box protrude into the box, the depressions 2 do not interfere with the welding wire since the welding wire is coiled.

Next, the gluing tabs 7 to 9 and 12 to 15 are glued to other portions, and the construction of the corrugated fiberboard packing box 1 containing the welding wire is thereby completed. When constructing the corrugated fiberboard packing box 1 and packing a welding wire therein, the corrugated fiberboard top portion 4 may be glued after all portions except for the corrugated fiberboard top portion 4 are glued and the welding wire is put in the box.

Since the corrugated fiberboard packing box 1 in which a welding wire is packed has the depressions 2 at four corners thereof, it can be carried very easily and reliably. The depressions 2 are not formed by cutting off the corners but provided by pressing the corners into the box, and therefore have high strength.

However, as described above, the depressions 2 at the four corners need to be formed after constructing a hexahedral rectangular parallelepiped corrugated fiberboard box 1 from a corrugated fiberboard blank (sheet), by pressing the four corners into the box mechanically with a pressing apparatus preferably in an automated process. (Pressing Apparatus) A pressing apparatus used for such a folding method of the present invention and a method for folding corners of a box for packing a welding wire using the pressing apparatus will be described with reference to FIGS. IA, IB, 1C, and 2. Folding Worktable: FIGS. 1A to 1C show a state where a box 1 for packing a welding wire is placed on a worktable 32. The box 1 is the subject of folding and is already constructed. The four corners of the worktable 32 are supported by supports 33. That is to say, the box 1 for packing a welding wire placed on the worktable 32 is preliminarily constructed from the corrugated fiberboard blank of FIG. 8, and a welding wire manufactured in a continuous manufacturing process is preliminarily put in the box 1 in the previous process.

After the corners of the box 1 for packing a welding wire are folded on the worktable 32, the box 1 is removed from the worktable 32 by an appropriate conveying unit so as to be moved from the manufacturing factory to a product warehouse or shipped.

The upper part of the box 1 for packing a welding wire placed on the worktable 32 is positioned and fixed by horizontal rollers 34, 34 (three horizontal rollers on each side in the figure) disposed on the worktable on each side of the box and. The side of the box 1 for packing a welding wire is positioned and fixed by vertical rollers 35, 35 (three vertical rollers on each side in the figure) disposed on each side of the box. A positioning stopper 36 protruding from the worktable 32 is located on the side of the box 1 for packing a wire for welding.

In this embodiment, as shown in FIGS. 1A to 1C, in order to form depressions 2 at the four corners of the corrugated fiberboard packing box 1, four pressing apparatuses 20 to 23 are disposed at positions where they face the four corners. The four pressing apparatuses 20 to 23 are placed under the worktable 32 and inclined upward so that their tips 25 face the four corners of the corrugated fiberboard packing box 1. Supporting members 24 support cylinders 31 of the pressing apparatuses 20 to 23 in an upward-inclined position.

Pressing Apparatuses:

The pressing apparatuses 20 to 23 are fluid cylinders having a pressing tip 25 having a shape corresponding to the shape of the depressions 2 at the four corners of the corrugated fiberboard packing box 1. The pressing apparatuses 20 to 23 each have a cylinder 31 with a bottom formed of metal and filled with operation oil, and a piston (rod) 30 that can slide (move back and forth) in the cylinder 31. Driven, for example, by oil pressure or air pressure, the pistons 30 can move forward, toward the four corners of the corrugated fiberboard packing box 1 and can be retracted into the cylinders 31.

Widely used known oil pressure cylinders or air pressure cylinders that convert fluid energy of liquid such as oil or gas such as air into linear movement of the rod 30 can be used as the fluid cylinders. Therefore, although not shown, the pressing apparatuses 20 to 23 each have a sealing member that seals the upper opening of the cylinder 31, and a hydraulic damper that is provided inside the cylinder 31 and that absorbs the pressing force contracting the cylinder 31 and the piston 30.

FIG. 2 is an enlarged view of the pressing tip 25 of each of the pressing apparatuses 20 to 23. The pressing tip 25 has such a fletching shape that three flanges (vanes) 26 are disposed around a shaft 27 in a radial fashion at regular angular intervals of 120 degrees, as a shape corresponding to the shape of the depressions 2 at the four corners of the corrugated fiberboard packing box 1. A

bearing portion 28 at the rear end of the shaft 27 has a hole 29 provided in the center thereof, and the piston 30 is fitted in the hole 29. The pressing tip 25 linearly reciprocates with the reciprocation of the piston 30. In the case of FIGS. 3A to 3C and 4 to 7, the shape of the depressions 2 is triangular pyramidal. A shape corresponding to the shape of the depressions 2 means a shape that can fit inside this triangular pyramidal shape.

The ridge lines of the front edges 26a of the three flanges (vanes) 26 have a tapered shape, that is, slope toward the back of the piston 30 (toward the right in the figure) so as to correspond to the shape of the folding lines 17 of the corrugated fiberboard blank of FIG. 8 and the shape of the ridge lines of the depressions 2 at the corners of the corrugated fiberboard packing box 1.

Folding Work:

The pressing apparatuses 20 to 23 have the above-described configuration. When folding the corners 2 of a box 1 for packing a welding wire, as shown in FIG. IB, the pressing tips 25 of the pressing apparatuses 20 to 23 are thrust linearly toward the four corners of the corrugated fiberboard packing box 1. The ridge lines of the front edges 26a of the pressing vanes 26 of the pressing apparatuses 20 to 23 press the folding lines 17 of the corrugated fiberboard box linearly from obliquely below.

Thus, the folding lines 17 are folded, and the depressions 2 (the ridge line shape of the depressions 2) at the corners of the corrugated fiberboard packing box 1 are formed.

As shown in FIG. 8, the folding lines 17 of the corrugated fiberboard box are preliminarily formed by three folding lines AB, BC, and CA that connect the three ridge lines AO, BO, and CO that meet at the corner 0. Therefore, the shape of the pressing tips 25 of the pressing apparatuses 20 to 23 shown in FIG. 2 includes three flanges (vanes) 26 that can press the three folding lines AB, BC, and CA and that correspond to the folding lines AB, BC, and CA, and tapered ridge lines of the front edges 26a thereof. Therefore, when the pressing tips 25 are thrust toward the four corners of the corrugated fiberboard packing box 1, the ridge lines of the front edges 26a of the pressing vanes 26 can press the three folding lines AB, BC, and CA, and folding can be smoothly performed to form the depressions 2 at the corners of the corrugated fiberboard packing box 1.

As described above, great force is necessary to press the triangular pyramidal portions that serve as the depressions 2 of the corrugated fiberboard packing box 1 and that are formed by the folding lines 17a, 17b, 17c, and 17d and the ridge lines OA, OB, and OC shown in FIG. 8, into the box. As described above, if the corner portions are manually pressed with a stick-like pressing member, the reaction force from the corner portions is great, and for example, the apex of the triangular pyramid is collapsed, or a hole is made.

However, making the pressing tips 25 in a shape corresponding to the shape of the depressions 2 at the four corners of the corrugated fiberboard packing box 1 makes it possible to easily form depressions at the corners of the corrugated fiberboard packing box 1 just by linearly pressing the corner portions with fluid cylinders, and to mass-produce packing boxes having depressions in an automated process. That is to say, the depressions 2 can be easily formed without using a pressing member that moves in a circular arc locus such as that described in Japanese Examined Patent Application Publication No. 7-115431.

The shape of the pressing tips 25 is not limited to the above-described three fletching 26 shape. The pressing tips 25 may have any shape as long as the shape corresponds to the above-described three folding lines AB, BC, and CA (the folding lines 17 of the corrugated fiberboard box or the ridge line shape of the depressions 2). The pressing tips 25 may have, for example, a conical or pyramidal shape having tapered protrusions corresponding to the ridge lines of the front edges 26a of the above-described three vanes 26.

As described above, the folding method of the present invention can easily and smoothly form the depressions 2 (the ridge line shape of the depressions 2) at the four corners of the corrugated fiberboard packing box 1 with the pressing apparatuses 20 to 23 that are fluid cylinders provided with a pressing tip. Therefore, the pressing apparatuses have a simple mechanism and can be reduced in size. Therefore, the installation space necessary for performing the method (work) of folding corners of a corrugated fiberboard packing box can be reduced.

It is to be understood that the present invention is not intended to be limited to the above-described embodiment, and various changes may be made therein. For example, depressions do not always have to be formed at the four corners of the bottom. A depression may be formed at at least one corner. In the above-described embodiment, four pressing apparatuses are placed at positions where they face the four corners of the bottom of a box. However, when forming depressions at a plurality of corners, for example, at two or four corners, the same number of pressing apparatuses shown in FIGS. 1A to 1C as the number of corners where depressions are formed need not be placed. For example, if a packing box is rotated, even a single pressing apparatus is enough. When forming depressions at the corners of the top of a packing box, the pressing apparatuses are moved.

By the present invention, depressions can be formed easily and quickly at corners of a corrugated fiberboard box for packing a welding wire, and highly portable packing boxes can be mass-produced. In addition, the depressions can be formed using pressing apparatuses that have a simple mechanism and that can be reduced in size. Therefore, the present invention is suitable to be applied to a continuous manufacturing process of a flux-cored welding wire that is required to have high production efficiency and quality assurance.

Claims

A folding method for forming a depression for grasping a corrugated cardboard box for packing a welding wire at a selected angle, the folding method comprising the steps of: provisionally forming folding lines serving as relief lines of the depression in a portion of a corrugated cardboard blank corresponding to the angle where the depression is formed; forming the corrugated cardboard blank provided with the folding lines into a box shape; and pressing in the corner of the corrugated box with an apparatus for applying pressure to form the depression, wherein the apparatus for applying pressure is a fluid cylinder provided with an end for applying pressure having a shape corresponding to the form of depression.

The method according to claim 1, wherein the angle of the corrugated cardboard box after placing a welding wire in the corrugated cardboard box formed into a box shape with the pressure-applying device is depressed to form the depression.

The method of claim 1, wherein the corrugated cardboard box formed into a box shape is placed on and attached to a work table, and then the fluid cylinder positioned opposite the corner of the corrugated cardboard box is activated to form the depression.

A method according to claim 1, wherein the pressure exerting end has a shape such that three flanges are arranged radially outwardly around the central axis of the fluid cylinder at regular angular distances of 120 degrees.