JPH0123367B2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention uses web as a packaging material,
The web is formed into a cylindrical shape, filled with a content such as a fluid food, and the cylindrical packaging material filled with the content is sealed and divided into lengths corresponding to one container.
The present invention relates to a device for folding a cylindrical packaging material into a rectangular tube shape for convenient molding operations in a subsequent process in a packaging machine that ultimately forms a rectangular parallelepiped container.

BACKGROUND ART When bending a cylindrical packaging material into a rectangular tube shape, it is possible to use a mandrel whose cross section gradually changes from a circle to a square from the top to the bottom. No. 136406.

When using the above mandrel, if the packaging material is made of paper, there is no problem because the packaging material after being folded into a rectangular tube shape will remain in the rectangular tube shape due to the shape retention of paper. If it is made of plastic, there is a problem in that it is difficult to bend due to the elasticity of the plastic.

When folding thermoplastic packaging materials, it is common practice to heat the packaging materials in advance. When trying to bend a cylindrical packaging material by fitting it onto the mandrel and feeding it, if the entire packaging material is heated,
When trying to send the packaging material, there is a risk that the packaging material may stretch, but in order to avoid this, a spot heater is used to locally heat only the part of the packaging material that should be folded. is also known (see, for example, Japanese Utility Model Application Publication No. 57-26301).

Problems to be Solved by the Invention As described above, when heating packaging materials with a spot heater, there are the following problems. 1st
Furthermore, the heated material cools down after it is heated and before it is bent, which may cause problems in bending. Furthermore, heating the material to the optimum temperature for bending may damage the material. Second, if the feeding speed of the packaging material is constant, there is no problem, but if the feeding speed fluctuates or is fed intermittently, uneven heating of the material occurs.

An object of the present invention is to provide a cylindrical packaging material folding device for a packaging machine that solves the above-mentioned problems.

Means for Solving the Problems A cylindrical packaging material folding device in a packaging machine according to the present invention has an upper part with a circular cross section, a lower part with a rectangular cross section, and a cylindrical packaging material folding device made of thermoplastic plastic that is fed downward. A vertical mandrel consisting of an intermediate part whose cross section changes from circular to rectangular from top to bottom so as to connect the upper and lower parts, and one each located on the diagonal extension of the rectangle formed by the lower part of the mandrel in plan view. four vertical hot air outlets extending along the mandrel from midway between the heights of the top and bottom of the mandrel and provided in the circumferential wall at intervals along its length with a plurality of outlets oriented toward the central axis of the mandrel; The tube and the four outer surfaces of the lower part of the mandrel are arranged below the lower end of the hot air blowing tube, one each, with a spacing sufficient to allow the packaging material to pass through while being lightly pressed, and each corresponding outer surface. It consists of four horizontal pressing rollers with a length equal to the width of the roller.

Function The folding device according to the present invention is fitted with a downwardly fed cylindrical packaging material made of thermoplastic plastic, and has an upper part with a circular cross section, a lower part with a rectangular cross section, and a cross section so as to connect the upper and lower parts. Since the vertical mandrel is provided with a middle section that changes from circular to square from top to bottom, the packaging material placed on the mandrel is transported from the top of the mandrel through the middle section to the bottom. , the packaging material is bent from a cylindrical shape to a rectangular tube shape.

Further, the bending device has one bending device located on each diagonal extension line of the rectangle formed by the lower part of the mandrel in plan view, extending along the mandrel from the middle of the height of the upper part to the lower part of the mandrel, and attached to the peripheral wall in the length direction of the bending device. There are four vertical hot air blow-off tubes with a plurality of spaced-apart blow-off ports directed toward the center axis of the mandrel, so that the packaging material can be bent from a cylindrical shape to a rectangular tube shape. Throughout the process, hot air is constantly blown from the outlets of the four hot air blowing pipes onto the corners of the square tube of the packaging material.

In addition, the folding device is arranged below the lower end of the hot air blowing pipe and corresponds to each of the four outer surfaces of the lower part of the mandrel, and is spaced so that the packaging material can be passed through while being lightly pressed. Since four horizontal pressure rollers are provided, each having a length equal to the width of the outer surface, the packaging material is passed between the mandrel and the rollers, thereby cooling the heated portion of the packaging material and packaging it. The material is molded to a certain thickness.

Embodiments Embodiments of the present invention will now be described with reference to the drawings.

First, before describing the cylindrical packaging material folding device in the packaging machine according to the present invention, the packaging material used in the packaging machine and the containers manufactured using the same will be described with reference to FIGS. 6 and 7.

As the packaging material 1, as shown in FIG. 6, a thermoplastic web is used.
Although not shown in detail, the plastic material is not limited to one type of plastic material, but is also a laminate of two or more plastic materials, and a laminate of one or more plastic materials and aluminum foil. The body is used. The packaging material 1 is provided with fold lines forming a required pattern in the vertical and horizontal directions, but of the pattern, only four fold lines 2 in the vertical direction that are directly related to the present invention are shown. This is a protrusion formed by bending the packaging material 1 itself along the fold line 2 into a substantially U-shaped cross section. Then, as shown in FIG. 7, a rectangular parallelepiped-shaped container 3 is formed from this packaging material 1 through a process described later. container 3
consists of a body 4 with a rectangular horizontal cross section, a flat top 5 and a flat bottom 6;
They each have transverse seals 7, 8 and triangular flaps 9, 10.

The cylindrical packaging material folding device is shown in Figures 1 to 5.
As shown in the figure, a vertical cylindrical mandrel 12, a heater 14 disposed along the mandrel 12, and a heater 14 disposed below the cylindrical packaging material forming apparatus 11, and a heater 14 disposed below the cylindrical packaging material forming apparatus 11, It consists of four pressing rollers 13 arranged so as to surround the mandrel 12.

The cylindrical packaging material forming device 11 forms a strip-shaped packaging material 1 into a cylindrical shape by joining the longitudinal ends thereof, and although not shown in its entirety, it uses a plurality of squeezing rollers 15 and a longitudinal seam. It is equipped with a seal roller 16 and the like. Each squeezing roller 15 has a concave outer circumferential surface, and each squeezing roller 15 is arranged in an annular manner such that the inner contour of these outer circumferential surfaces forms a circle as a whole. One squeeze roller 15 out of all the squeeze rollers 15 has a spring 17
It is elastically supported inwardly by. The seal roller 16 has a convex outer circumferential surface, and the outer circumferential surface is brought into contact with one squeezing roller 15 supported by a spring 17. Also, mandrel 1
A liquid supply pipe 18 of the filling device is inserted through the center of the shaft of the filling device.

The mandrel 12 has an upper part 19 with a circular cross section, a lower part 21 with a rectangular cross section, and an upper part 19 and a lower part 21.
It consists of an intermediate part 20 whose cross section changes from circular to rectangular from top to bottom so as to communicate with each other.
The lower part 21 occupies almost the entire lower half of the mandrel 12, and has a shape that matches the inner surface of the body 4 of the container 3, and has a crease line 2 at the corner of the rectangle.
is being distracted.

The heater 14 heats and softens the packaging material 1 by blowing hot air thereon, and includes four vertical hot air blowing pipes 23 and a hot air supply pipe 24 connected to each hot air blowing pipe 23. The hot air blowing pipes 23 are rectangular cylinders having a square cross section with both ends closed, and are located one each on the diagonal extension line of the rectangle formed by the mandrel portion 21 in a plan view. It extends along the mandrel 12 to the middle of the length, and its lower end reaches just above the pressure roller 13. A plurality of blow-off ports 25 are provided on the peripheral wall of the hot-air blow-off tube 23 at intervals in the length direction thereof so as to be oriented toward the mandrel center axis.

Of the four pressure rollers 13, two are long pressure rollers 13, and the remaining two are short pressure rollers 13.
The long and short lengths match the widths of the four outer surfaces of the lower mandrel 21. The four pressing rollers 13 are arranged one on each of the four outer surfaces and are spaced apart from each other so that the packaging material 1 can be lightly pressed and passed through. They are connected to form a ring.

The packaging material 1, which is fed vertically downward and forward, is formed into a cylindrical shape by a cylindrical packaging material forming device 11, and then fitted onto a mandrel 12. While the packaging material 1 passes along and around the outer peripheral surface of the mandrel 12, the packaging material 1 deforms from a cylindrical shape to a rectangular tube shape, but during this deformation process, the packaging material 1 breaks. By blowing hot air onto the part at the grain line 2 by the heater 14, the part is locally heated and softened, so that the packaging material 1 can be easily folded along the crease line 2. The packaging material 1 bent into a rectangular tube shape is passed between the mandrel 12 and the pressing roller 13 immediately before being removed from the mandrel 12. As a result, the softened portion of the packaging material 1 along the fold line 2 is cooled and plasticized, and the packaging material 1 that has come out of the mandrel 12 maintains its rectangular tube shape.

Effects of the Invention According to the present invention, the packaging material placed on the mandrel is bent from a cylindrical shape to a rectangular tube shape while being fed from the upper part of the mandrel to the lower part via the middle part. During this time, hot air is constantly blown from the outlets of the four hot air blowing pipes onto the corners of the rectangular tube of the packaging material. It does not interfere with the folding operation, and even if the feeding speed of the packaging material fluctuates, the effect of the fluctuation is relatively small because the hot air is blown over a certain length of the packaging material. It is difficult for uneven heating to occur.

In addition, by passing the packaging material between the mandrel and the rollers, the heated portion of the packaging material is cooled and the packaging material is formed to a certain thickness, ensuring reliable folding work. be done.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the entire device showing an embodiment of the present invention, FIG. 2 is a vertical longitudinal sectional view of the entire device, and FIG.
The figure is a cross-sectional view of the area around the squeezing roller of the cylindrical packaging material forming device taken along the - line in Figure 2, and Figure 4 is a cross-sectional view of the area around the squeezing roller of the cylindrical packaging material forming device.
The - line in the figure shows a cross-sectional view of the area around the hot air blowing pipe, the - line in Figure 2 shows a cross-sectional view of the area around the pressing roller, Figure 6 is a perspective view of the packaging material, and Figure 7 shows the container. FIG. 1... Packaging material, 12... Mandrel, 13...
...press roller, 19...upper part, 20...middle part,
21... lower part, 23... hot air blowing pipe, 25...
Air outlet.

Claims (1)

[Claims] 1. An upper part 19 with a circular cross section, a lower part 21 with a rectangular cross section, and an upper part 19 on which a cylindrical packaging material 1 made of thermoplastic plastic that is fed downward is fitted.
a vertical mandrel 12 consisting of an intermediate part 20 whose cross section changes from circular to rectangular from top to bottom so as to communicate with the lower part 21; A plurality of air outlets 25 are provided on the peripheral wall at intervals in the length direction of the mandrel, extending along the mandrel 12 from the height of the upper part 19 to the lower part 21 of the mandrel, and facing the central axis of the mandrel. and four vertical hot air blowing pipes 23 located below the lower end of the hot air blowing pipes 23, one for each of the four outer surfaces of the lower mandrel 21, at intervals large enough to allow the packaging material 1 to pass through while being lightly pressed. 4. A device for folding cylindrical packaging material in a packaging machine, comprising: four horizontal pressing rollers 13 arranged such that the width of each outer side is maintained and having a length equal to the width of each corresponding outer surface.