JPS6120428B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing boxes using thermoplastic resin plates.

According to the present invention, it is easy to insert the box-expanded body into the box forming mold, it is easy to lift up the side plate corresponding parts, and the mutual abutting parts of the ends of the side plate corresponding parts are reliably fused. It is an object of the present invention to provide a method for manufacturing a thermoplastic resin box that can be easily attached, has high strength, and has a good finished appearance.

That is, the method for manufacturing a thermoplastic resin box according to the present invention involves forming a box-expanded body in a box-expanded shape consisting of a bottom plate corresponding portion and a side plate corresponding portion from a plate-like body made of a thermoplastic resin, and A step of forming a groove in the boundary between the side plate and the corresponding portion of the side plate, a step of heating and softening a portion of the back surface corresponding to the groove, and a step of forming four constituent molds, and at least two opposing constituent molds are movable. Place the expanded box body facing the cavity in the mold of a box forming mold provided in the mold, and forcibly insert the expanded box body into the cavity in the mold, As the insertion progresses, at least two opposing structural molds are moved toward each other in a direction to gradually raise the corresponding side plate part around the groove, and the corresponding part of the side plate is completely raised. In the hanging state or in the process of rising, a movable heating knife is inserted between the mutual abutting parts of the ends of each side plate to heat and melt the mutual abutting parts, and then the heating knife is retreated. , and a step of fusing the mutually abutting portions.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Reference numeral 1 denotes a rectangular plate-shaped body made of thermoplastic resin, such as expanded polystyrene, and cut into a predetermined size in advance. This plate-shaped body 1 is placed on a mounting table 2. Reference numeral 3 denotes a heating section opening groove provided in the mounting table 2, and 4 a heating element housed and installed along the heating section opening groove 3.

Above the plate-shaped body 1, there is a square-shaped main frame 5, a pressing blade 6 formed around the main frame 5 in a rectangular shape corresponding to the opening groove 3, and protruding downward, and The pressing blade 6 is connected to the blade 6 and has a hook shape.
A blade mold 8 consisting of a cutting blade 7 formed to protrude further downwards is facing, and the blade mold 8 is lowered and the four corners of the plate-shaped body 1 are shaped into a hook shape by the cutting blade 7. Cut out the bottom plate corresponding parts 9 and 4 as shown in Figure 5.
A box-expanded body 14 having a box-expanded shape is formed from three side plate corresponding parts 10, 11, 12, and 13.
By the cutting, as shown in FIG.
is obtained as the cut surface. At the same time as the cutting, the pressing blade 6 comes into contact with the boundary between the bottom plate corresponding part 9 and the side plate corresponding parts 10 to 13 on the surface 15 of the box development body 14, and presses and crushes the boundary, so that the cross section V
A character-shaped groove 16 is formed, and a portion 17a of the back surface 17 corresponding to the groove 16 is heated and softened by the heating element 4 (FIG. 3).

Next, the box development body 14 is set in the box forming device.
The box forming device has four molds 19, 20, each having a mounting portion C which is arranged to form a cavity 18 in the mold into which the box development body 14 is inserted and which is movable in the horizontal direction. 21 and 22, and a cavity 18 in the box forming mold 23.
A push-in plate 2 is provided that can be raised and lowered to move up and down.
4, a support plate 25, and four heating knives 26 provided horizontally movably in the vicinity of the box forming mold 23. As the heating knife 26, one with a built-in heater can be used, or one without a built-in heater and heated by a heating furnace can be used. In the latter case, a heating furnace is installed on the movement locus of the heating knife 26, and the heating knife 26 heated to a constant temperature in the heating furnace is moved forward, and the heating knife 26 that comes out of the heating furnace is attached to each side plate, which will be described later. It can be configured to be inserted between the mutually abutting parts of the ends of the parts.

The side plate corresponding parts 10 to 13 of the box development body 14 are placed on the placing part C of the box forming mold 23, and the bottom plate corresponding part 9 is placed on the support plate 25, and the area is wider than the bottom plate corresponding part 9. The box is expanded facing the cavity 18 in the mold, which has an opening area and has an opening area adjusted to a size necessary for smooth and easy insertion of the box deployment body 14 into the cavity 18 in the mold. Body 14 into box forming mold 2
3 (FIG. 6), and then lower the push plate 24 to press downward the bottom plate corresponding part 9 of the expanded box body 14, and forcibly insert the expanded box body 14 into the cavity 18 in the mold. do. At this time, the support plate 25 is lowered synchronously following the movement of the pushing plate 24. As mentioned above, the cavity 18 in the mold has an opening area larger than the area of the bottom plate corresponding part 9, and the size necessary for smoothly and easily inserting the box development body 14 into the cavity 18 in the mold. Since the opening area is precisely adjusted, the box development body 14 can be inserted smoothly and easily. As the box development body 14 is inserted into the mold cavity 18, the side plate corresponding parts 10 to 13 gradually rise up around the groove 16, but as the box development body 14 is inserted into the mold cavity 18, the side plate corresponding parts 10 to 13 gradually rise up, but as the box development body 14 is inserted into the mold cavity 18, the side plate corresponding parts 10 to 13 gradually rise up. Constructive types 19 and 21 and 20 and 2
2 move closer to each other and the opening area of the cavity 18 in the mold gradually becomes smaller, so that the side plate corresponding parts 10 to 13 increasingly stand up vertically.
Eventually, the side plate corresponding parts 10 to 13 will become structured types 19 to 22.
When the entire surface is in contact with the inner wall surface of the side plate corresponding part 10-1
3 stands completely vertically (Figure 7). At this point, the movement of each of the structural molds 19 to 22 is temporarily stopped.

The operation of raising the side plate corresponding portions 10 to 13 is performed while the aforementioned back portion 17a is in a softened state. Here, since the back surface portion 17a is heated and softened, no internal strain occurs in the back surface portion 17a when the side plate corresponding portions 10 to 13 are raised.
Therefore, the rising operation is easy, and a straight and neat bent portion 27 is formed. Furthermore, since the back surface portion 17a is softened, the stress acting on the bending portion 27 during the rising operation is significantly reduced, and as a result, the bending portion 27 is not rounded but has a sharp corner. At the same time, there is no risk of cracks occurring in the bent portion 27.

After the raising operation of the side plate corresponding parts 10 to 13 is completed, the heating knife 26 moves forward, and as shown in FIGS. The tip of the heating knife 26 is inserted between the respective mutual contact parts with the inner wall surfaces 10a and 12a, and after heating and melting the mutual contact parts, the heating knife 26 is immediately retreated from between the mutual contact parts. After separating, the structural molds 19 and 21 move slightly in the direction of approaching each other, and the side plate corresponding parts 10 and 12
is pressed toward the edge B side, and the edge B and the inner wall surface 10 of the end portion are pressed together.
a and 12a are closely pressed together to fuse the mutual contact portions. As a result, a box 28 is formed, as shown in FIG. 10, consisting of a bottom plate based on the bottom plate corresponding part 9 and four side plates based on the side plate corresponding parts 10 to 13.

Next, the constituent molds 19 and 21 and 20 and 22 move in the direction of separating from each other, and the pushing plate 2
4 and the support plate 25 rise, and when the support plate 25 returns to its old position, the rise of the support plate 25 stops, and at this time, a suction device (not shown) operates, and the push plate 24 rises while holding the box 28 by suction. When a suitable raised position is reached, the direction is changed, and at this point the operation of the suction device is stopped and the box 28 is removed from the push plate 24 and collected in the product storage area. The above-mentioned suction device is, for example, one in which the push plate 24 is provided with a large number of suction ports connected to a suction pump, and the box 28 is sucked by driving the suction pump.

In the embodiment described above, all of the structural molds 19 to 22 are provided movably, but only the structural molds 19 and 21 that press the side plate corresponding parts 10 and 12 may be made movable, and the others may be provided fixedly. Even in this case, the opening area of the mold cavity should be set to be larger than the area of the bottom plate corresponding part 9 and to a size necessary to smoothly and easily insert the box development body 14 into the mold cavity 18. Since the box development body 14 can be easily inserted into the cavity in the mold, and since the side plate corresponding parts 10 and 12 can be pressed, there is no problem in fusing the mutually abutting parts of the ends of the side plate corresponding parts. do not have.

In the embodiment, the side plate corresponding parts 10 to 13
The edge B of is formed perpendicular to the inner wall surface A, but
As another embodiment of the present invention, the edge B may be formed as a tapered surface at an obtuse angle with respect to the inner wall surface A, as shown in FIG. In this case, as shown in FIG. 12, a heating knife 26 is inserted between the mutually abutting portions of the edges B and B to melt and fuse them. In this case, when the heating knife is retreated to fuse the mutually abutting portions, the four structural molds 19 to 22 are moved in a direction toward each other. 2
Although it is possible to fuse by simply moving the four constituent molds 19, 21 or 20, 22, it is better to move the four constituent molds 19 to 22 because the edges B and B can be more strongly pressed against each other, so the former preferable than the case.

The grooves 16 can be formed by forming the grooves using a pressing blade as described in the above embodiments, or by heating and melting the plate-like material using a heating blade, or by cutting using a cutting blade. It is also possible to adopt a method of forming a . The cross-sectional shape of the groove 16 is not limited to the V-shape, but may be any concave groove, for example, any shape. Further, in the embodiment, the side plate corresponding portions 10 to 1
3 was fully raised, the heating knife 26 was inserted between the mutually abutting parts of the ends of the side plate corresponding parts. Thereafter, the corresponding side plate portions 10 to 13 may be completely raised to contact the heating knife 26. Using a Teflon-treated heating knife is advantageous in that it can prevent molten resin gas from adhering to it.

As the box material in the present invention, polystyrene,
Use a thermoplastic resin such as a two-component copolymer of butadiene-styrene, a two-component copolymer of acrylonitrile-styrene, a three-component copolymer of acrylonitrile-butadiene-styrene, or polystyrene made by mixing polyethylene. I can do it.
In the present invention, it is preferable to use a foam; for example, in the case of foamed polystyrene, the density is
Suitable materials have a weight of 0.03 to 0.2 g/cm ³ , preferably 0.05 to 0.1 g/cm ³ and a thickness of 1.5 to 10 mm, preferably 2 to 6 mm.

As explained above, in a box forming mold consisting of four constituent molds, the present invention makes at least two opposing constituent molds movable. It can be adjusted to a size that is larger than the area of the mold and that is necessary for smoothly and easily inserting the expanded box body into the cavity in the mold, and as a result, the insertion work of the expanded box body is smooth and easy. In addition, there is an effect that it is possible to carry out a wide range of operations, and there is also an effect that it is extremely versatile as there is no need to prepare various box molds depending on the size of the box development body. In addition, by heating and melting the mutual abutting portions at the ends of the corresponding portions of each side plate with a heating knife, and then moving the structural mold, the mutual abutting portions can be closely pressed together to achieve strong fusion. It has the advantage of being able to apply the necessary pressing force.

In addition, since the heating knife is made movable, there is no problem that the heating knife gets in the way of insertion when the box development body is inserted into the mold cavity, and the heating knife can be easily cleaned and replaced. As a heating means, in addition to the heating method using a heater, there is an advantage that a heating method using a heating furnace can be used. According to the present invention, since it is possible to immediately fuse the mutually abutting portions of the corresponding portions of the side plates by heating and melting them with a heating knife, the corresponding portions of the side plates can be fused immediately after the mutually abutting portions are heated and melted. Compared to the method of starting up and then fusing, the time from heating and melting to fusing is extremely short, and fusing can be achieved in ideal conditions. The joint strength at the points is very high, and a box with a good finished appearance can be manufactured. Furthermore, if the molding is performed immediately after heating and melting (pressing with a constituent mold), the bonding strength can be further increased.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of the configuration of the device used in the box development process. Figure 1 is a back view of the blade mold,
The figure is a plan view of the mounting table, FIG. 3 is a vertical cross-sectional view showing the state of groove formation in the box development process, and FIG. 5 is a plan view of the developed box obtained in the above process, FIGS. 6 to 9 show the box forming process, and FIG. 6 is a longitudinal cross-section showing the state of the corresponding part of the side plate before the rising operation. Figure 7 is a vertical cross-sectional view showing the state of the corresponding part of the side plate after the rising operation, and Figure 8 is a partial cutaway showing the state in which the heating knife is inserted between the mutual abutting parts of the ends of the corresponding part of each side plate. FIG. 9 is a schematic plan view showing the heating knife inserted, FIG. 10 is a perspective view of the box obtained by the above process, and FIG. 11 shows the edge of the side plate as a tapered surface. FIG. 1 is a plan view of main parts showing another embodiment of the present invention when the
FIG. 2 is a schematic plan view of a main part showing a state in which a heating knife is inserted when the end edge is a tapered surface. 1... Plate-shaped body, 9... Bottom plate corresponding part, 10,1
1, 12, 13... Applicable part of side plate, 14... Box development body, 16... Groove, 18... Hollow space in mold, 19, 2
0, 21, 22...Construction type, 23...Box forming type,
26... Heating knife.

Claims (1)

[Claims] 1. A process of forming a box-shaped developed body consisting of a bottom plate corresponding part and a side plate corresponding part from a plate-shaped body made of thermoplastic resin, and forming a groove at the boundary between the bottom plate corresponding part and the side plate corresponding part. and a step of heating and softening the parts of the back surface corresponding to the grooves, and a step of heating and softening the parts of the back surface corresponding to the grooves, and exposing the mold to the hollow space of the box-forming mold, which has four constituent molds and at least two opposing constituent molds are movably provided. the box development body is placed on the box development body, and the box development body is forcibly inserted into the mold cavity, and as the box development body is inserted into the mold cavity, at least two opposing configuration molds are inserted. The process of gradually raising the relevant parts of the side plates around the grooves by moving them in the direction of approaching each other, and when the corresponding parts of the side plates are completely raised or in the process of rising, The method comprises the steps of inserting a movable heating knife between the mutually abutting portions, heating and melting the mutually abutting portions, and then retracting the heating knife to fuse the mutually abutting portions. A method for producing a characteristic thermoplastic resin box.