JPH0890563A - Mold and method for producing foamed molded box equipped with undercut part - Google Patents

Abstract

PURPOSE: To prevent an increase in the number of parts while simplifying a molding work in the production of a foamed molded box equipped with an undercut part. CONSTITUTION: A fixed mold 1 having a cavity side inner hold 4 is provided and the core side inner mold 9 provided to a movable mold 8 is constituted of the fixed mold 11, a pair of first movable cores 14 for forming an undercut part and a pair of the second movable molds 18 interposed between the fixed molds 11 and the first movable cores 14. The fixed mold 11 is fixed to the mold attaching plate 10 provided to the front of the movable mold 8 and a pair of the first movable cores 14 are respectively connected to the up-and-down moving cylinder 15 of the movable mold 8 and a pair of the second movable cores 18 are connected to the right and left moving air cylinders 19 of the back plate 12 of the movable mold 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for molding a styrofoam box having an undercut portion (generally referred to as a freezing box) and a molding method therefor.

[0002]

2. Description of the Related Art There are various containers for storing articles, and one of them is a rectangular Styrofoam box (hereinafter, referred to as a foam molding box) 22 as shown in FIG. The foam-molded box 22 is widely used for packaging seafood and foods because it has excellent shock absorption and flexibility, withstands repeated deformation, and produces little dust. When molding such a foam molding box 22, first, a core side inner die of a movable die is clamped to a cavity side inner die of a fixed die (not shown), and a foam molding material (foam polystyrene) is placed in the molding cavity. Etc., and then steam is introduced into the fixed mold and the movable mold respectively to foam-mold the foam molding material, cool the foam molding material, and then from the fixed mold to the movable mold. If the foam-molded box 22 is dried after the mold is opened,
Can be taken out. By the way, when the seafood, vegetables, etc. are stored in the foam-molded box 22, these are stored in the foam-molded box 2.
So that it does not easily come out of 2 and fall
There may be times when we want to make some structural improvements. In addition, when stacking a plurality of foam-molded boxes 22 containing fresh foods,
Make sure that the upper foam-molded box 22 does not fall into the lower foam-molded box 22 and damage the fresh food or the like.
There are times when I want to make some structural improvements. Therefore, in order to meet these requirements, conventionally, as shown in FIG.
As shown in (b), the undercut portions 23 are formed on both short side edges of the upper part of the opening of the foam-molded box 22 so as to be directed toward the center, respectively. I try to prevent the fall.
In addition, undercut is a shape that the molded product cannot be taken out of the mold.Generally, when designing the product, from the viewpoint of simplifying the mold structure and preventing mold accidents, there is no undercut. It is desired to design.

[0003]

However, in the conventional foam molding box molding apparatus, it was structurally impossible to mold the undercut portion 23 in the foam molding box 22 as it is. When it is inevitable to form the undercut portion 23 in the foam molded box 22, the foam molded box 2
It was necessary to attach a dedicated part to the second molding device and mold. Therefore, when forming the undercut portion 23, there is a problem that the number of parts is increased and the forming operation is complicated.

The present invention has been made in view of the above problems, and it is possible to prevent an increase in the number of parts and to further simplify the molding work. It is intended to provide a molding method thereof.

[0005]

In the first aspect of the present invention, in order to achieve the above object, a fixed die having a cavity side inner die and a core side inner die provided in a movable die are provided. A fixed die, a first movable core for forming an undercut portion, and a second movable core interposed between the fixed die and the first movable core, and the fixed die is provided on the movable die. Fixed to the mounting plate, the first movable core is connected to a vertically moving air cylinder provided on the movable mold, and the second movable core is moved horizontally on the back plate of the movable mold. It is connected to the air cylinder. In addition, it is preferable that the first movable core includes a forming portion that forms an inner and an outer of the undercut portion. Further, it is preferable that the second movable core has a hollow portion, and a communication hole is provided in the hollow portion. Further, in the second aspect of the present invention, in order to achieve the above object, the fixed die of the movable die, the first movable core, and the second movable core are provided to each other with respect to the fixed die having the cavity side inner die. Engage to form a core side inner mold, and in this state, the movable mold is clamped to perform foam molding, and after the foam molding is completed, the second movable core is moved to the left and right, and then the first mold The movable core is moved in the vertical direction, and the movable mold is opened in this state.

[0006]

According to the first and second aspects of the present invention having the above structure, first, the core side inner die of the movable die is clamped to the cavity side inner die of the fixed die, and foam is formed in the forming cavity. The molding material is filled. At this time, the first
The movable core is arranged at the molding position of the undercut portion, and the second movable core is interposed at the molding position to mold part of the inside of the foam molding box and the inner and outer of the undercut portion, respectively. Then, the foam molding material in the molding cavity is heated by a heating medium such as steam to foam-mold. Then, when the heat molding of the foamed molding material is completed, the foamed molding material in the molding cavity is cooled by a cooling medium such as cooling water, and then the cooling medium that has finished its role is discharged. When the cooling of the foamed molding material is completed in this way, the second movable core is moved in the mold opening direction of the movable mold by the driving of the left-right moving air cylinder to form the escape space for the first movable core. Then, the first movable core is retracted in the inward direction orthogonal to the mold opening direction of the movable mold by the protruding drive of the vertically movable air cylinder, and is brought close to the end of the fixed mold, thereby interfering with the undercut part. To avoid. Then, while the movable mold is opened from the fixed mold,
After the foam molded box with the undercut part is released, after the foam molded box with the undercut part is dried,
All work is completed. In this way, the undercut portions are formed on the short side edges of the upper opening of the foam-molded box, and are commercialized. Further, according to the invention of claim 3, since the second movable core has a hollow portion and the communication hole is provided in this hollow portion, steam or cooling water flows into the hollow portion and the foam molding material is provided. Is heated or cooled.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the molding die of the foam molding box having the undercut portion according to the present embodiment is a fixed die 1.
And a movable mold 8 that can be opened and closed, and the movable mold 8 faces the fixed mold 1.

The fixed mold 1 is provided with a steam chamber 2 therein, a cavity-side inner mold 4 is arranged on the mold mounting plate 3 on the front surface, and a back plate 5 is arranged on the rear surface. Although not shown, the fixed mold 1 is provided with a support, a steam inlet, a steam dispersion plate, a cooling water inlet, a cooling water pipe, a spray nozzle, and a drain outlet. Further, as shown in FIG. 1, a plurality of raw material fillers 6 for filling the cavity side inner mold 4 with a foaming molding material (for example, foamed polystyrene, polyethylene, polyurethane, polypropylene, etc.) are inserted through the back plate 5. A plurality of ejector rods 7 for releasing are inserted so that they can be moved back and forth in the left-right direction in FIG. It should be noted that the mounting location, shape, structure, number or the like of the cavity side inner mold 4, the raw material filler 6, or the ejector rod 7 can be appropriately increased or decreased.

On the other hand, the movable mold 8 is, as shown in FIG.
A core side inner die 9 is disposed on the front surface thereof, and the core side inner die 9 is composed of a fixed die 11, a pair of first movable cores 14, and a pair of second movable cores 18. The movable mold 8 is provided with a fixed mold 11 via a support (not shown) on a mold mounting plate 10 at the center of the front surface thereof, and a back plate 12 at the rear thereof.
By detecting (for example, various sensors such as a proximity switch and a limit switch), the fixed mold 1 is operated to open and close in the left-right direction in FIG. Although not shown, the movable mold 8 is provided with a steam inlet, a cooling water inlet, a drain outlet, and the like, and heats the foam molding material between the core-side inner mold 9 and the mold mounting plate 10. -The steam chamber 13 for cooling is partitioned and formed, and steam and cooling water flow into and diffuse into the steam chamber 13. Further, as shown in FIG. 1, the fixed mold 11 is disposed so as to face substantially the center of the cavity surface of the cavity-side inner mold 4. It should be noted that, depending on the shape and number of the undercut portions 23, the mounting location, shape, structure, or number of the core-side inner die 9 and the fixed die 11 may be increased or decreased as appropriate.

As shown in FIGS. 1 and 2, first movable cores 14 are arranged above and below the fixed mold 11, respectively. The pair of first movable cores 14 is formed in a bent structure so that the inner and outer parts of the undercut portion 23 can be molded, and the protruding engaging pieces 14a extending vertically from the outer side surface of the die mounting plate 10A. The end is slidably slidably contacted. In addition, a plurality of vertically moving air cylinders 15
Are attached to the upper and lower ends of the movable mold 8, and the pistons that can move back and forth are inserted into the guides 16 of the mold mounting plate 10A, and the tips of the pistons are respectively attached to the ends of the first movable core 14. It is connected. The plurality of vertically moving air cylinders 15 are driven by detection of sensors (not shown) (for example, various sensors such as proximity switches and limit switches). Therefore, each first movable core 14
1 is arranged at the undercut portion molding position in FIG. 1 during mold clamping, and functions to mold a part of the inner bottom surface, a part of the inner wall surface and the inner / outer of the undercut portion 23 in the foam molding box 22. The undercut portion 23
The mounting location, shape, structure, or number of the first movable core 14 or the vertically moving air cylinder 15 can be appropriately increased or decreased depending on the shape or number of the above. For example, the number of the first movable cores 14 may be one or a plurality of three to four. Further, the vertical moving air cylinder 15 may be one, or three to four. Further, it goes without saying that instead of the vertically moving air cylinder 15, other types of cylinders such as a hydraulic cylinder may be used, and further other actuators or motion transmission mechanisms may be used.

Further, as shown in FIGS. 1 and 2, second movable cores 18 having communication holes 17 are arranged between the fixed die 11 and the pair of first movable cores 14, respectively, and the second movable cores 18 are provided. The end of the core 18 is connected to the tip of the piston of the left-right air cylinder 19. The left-right moving air cylinder 19 is attached to the back plate 12, and the second movable core 18 that can move forward and backward at the piston tip is inserted into the guide 21 of the die mounting plate 10.
Further, the hollow portion 20 acts to heat or cool the foam molding material by the inflow of steam or cooling water (not shown), as in the steam chamber 13. Therefore, each of the second movable cores 18 is disposed at the molding position in FIG. 1 during mold clamping, and molds a part of the inner bottom surface and a part of the inner wall surface of the foam molding box 22. Before releasing the mold, the left and right moving air cylinders 19 are driven to move in the mold opening direction of the movable mold 8 (rightward in FIG. 2) to form a retracting space for the first movable core 14. are doing. In addition, depending on the shape and number of the undercut portion 23, the communication hole 17, the second movable core 18, the left-right moving air cylinder 19, or the hollow portion 2
It is possible to freely increase or decrease the number of attachment points, shape, structure, number, etc. For example, the second movable core 18 is 1
One or a plurality of 3 to 4 may be used. Further, the left and right moving air cylinders 19 may be one or three to four. Also, the second
It goes without saying that the movable core 18 and the first movable core 14 may be present at least on one end side of the fixed mold 11. Also, instead of the left-right air cylinder 19, another type of cylinder such as a hydraulic cylinder may be used,
Furthermore, it is also possible to use an actuator, a motion transmission mechanism, or the like.

Next, a molding method using the above molding apparatus will be described. When molding the foam molding box 22 having the undercut portion 23, first, as shown in FIG. 1, the core side inner die 9 of the movable die 8 is clamped to the cavity side inner die 4 of the fixed die 1. Then, the foaming molding material is uniformly filled in the molding cavity by the plurality of raw material filling devices 6. At this time, each of the first movable cores 14 is arranged at the molding position of the undercut portion, and each of the second movable cores 18 is arranged at the molding position, and a part of the inner bottom surface of the foam molding box 22 and one of the inner wall surfaces are arranged. Section and undercut section 2
Inner and outer parts of 3 are molded respectively. Then
High-temperature, high-pressure steam flows into and out of the steam chambers 2 and 13 and the second movable core 18 from the steam inlets of the fixed mold 1 and the movable mold 8 via the steam dispersion plate, and foam molding of the molding cavity. The material will be heated and foam molded. The steam flows into the hollow portion 20 of the second movable core 18 via the communication hole 17 to heat the foam molding material. Thus, when the heat molding of the foam molding material is completed,
The cooling water is passed through the cooling water inlets of the fixed mold 1 and the movable mold 8, the cooling water pipe, and the spray nozzle in this order to the steam chamber 2.1.
3 and the second movable core 18 respectively inflow and diffusion,
The foamed molding material in the molding cavity is cooled, and then the cooling water which has finished its role is discharged from the drain outlet. In addition,
This cooling water passes through the communication hole 17 and then the second movable core 1
8 into the hollow portion 20 to cool the expanded foam molding material.

When cooling of the foamed molding material is completed, each second
The movable core 18 is moved in the mold opening direction of the movable mold 8 by the driving of the left-right moving air cylinder 19 to form a retracting space for the first movable core 14. When the movement is detected by the sensor, each first movable core 14 is displaced by retracting in the inward direction orthogonal to the mold opening direction of the movable mold 8 by the upward driving of the vertically moving air cylinder 15, and the upper and lower ends of the fixed mold 11 are moved. And the interference with the undercut portion 23 is avoided in advance. When the evacuation is detected by the sensor, the movable mold 8 is opened from the fixed mold 1, and the plurality of ejector rods 7 project rightward in the drawing to cause the undercut portion 23.
After the foam molded box 22 provided with is released from the mold, and the foam molded box 22 provided with the undercut portion 23 is dried, all the operations are completed. In this way, FIG.
As shown in (a) and (b), the undercut portions 23 are molded on the short side edges of the upper opening of the foam molding box 22, respectively, to be commercialized. When it is desired to change the shape or structure of the foam-molded box 22, the shapes of the cavity-side inner die 4 and the core-side inner die 9 may be changed accordingly. Further, the upper, lower, left and right directions of the molding die of the foam molding box having the undercut portion can be freely changed without being limited to the illustrated example. Undercut portion 23 on the short edge
It is clear that each can be molded.

According to the above construction, before the mold is opened, the second movable core 18 moves in the mold opening direction of the movable mold 8 to move the first movable core 18 into the first mold.
A retractable space for the movable core 14 is formed, and the first movable core 1
Since 4 is an inward direction orthogonal to the mold opening direction of the movable mold 8 from the undercut portion molding position, in other words, it is evacuated to a safe non-interference position to avoid collision / interference with the undercut portion 23 in advance. The foam-molded box 22 having the undercut portion 23 can be molded extremely easily without attaching a dedicated part to the molding device of the foam-molded box 22.
Therefore, it is possible to reliably prevent an increase in the number of parts and complication of the molding work. Further, through this, it is expected that the manufacturing cost will be significantly reduced, the product value will be significantly improved, and the variety of products will be increased. Further, it is possible to reliably prevent the undercut portion 23 of the foam molding box 22 from being damaged, and it is possible to open the movable mold 8 extremely smoothly. Further, since the second movable core 18 is provided with the hollow portion 20 and the communication hole 17 is provided in this hollow portion 20, uniform heating / cooling of the entire foam molding material can be expected. Further, the vertical movement air cylinder 15 is driven to project for the first time by the detection of the sensor, so that the interference and collision of the air cylinders 15 and 19 can be reliably prevented. Furthermore, as an actuator, an air cylinder 1
Since 5 ・ 19 is used, output adjustment is significantly facilitated, safety is ensured, high-speed operation is realized, energy is stored, explosion and ignition are reliably prevented, use is greatly simplified, and mechanism is greatly simplified. It is expected that maintenance and inspection will be greatly facilitated and remote operation will be realized.

[0015]

As described above, according to the first and second aspects of the present invention, the core side inner die is divided into three parts, that is, the fixed die, the first movable core, and the second movable core, and Since the first movable core and the second movable core are operated by the air cylinders respectively, there is a particular effect that it is possible to reliably prevent an increase in the number of parts and complication of molding work. In addition, through this, it can be expected to reduce the manufacturing cost, improve the product value, and increase the variety of products. In addition, it is possible to prevent damage to the undercut portion of the foam molding box, and it is also possible to smoothly open the movable mold. And, because an air cylinder is used, it is easy to adjust the output, ensure safety, realize high-speed operation, store energy, prevent explosion and ignition, simplify use, simplify the mechanism, and facilitate maintenance and inspection. , And remote control can be expected. Further, the second movable core has a hollow portion,
Since the hollow portion is provided with the communication hole, there is a remarkable effect that uniform heating / cooling of the foam molding material can be expected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molding die of a foam molding box having an undercut portion according to the present invention and a state at the time of molding of the molding method.

FIG. 2 is a cross-sectional view showing a state of a molding die of a foam molding box having an undercut portion and a molding method thereof according to the present invention at the time of mold release.

FIG. 3 (a) is a perspective view showing a state where an undercut portion is formed on each of the short side edges of the upper opening of the foam molding box,
(b) is the sectional drawing.

FIG. 4 is a perspective view showing a foam molded box having no undercut portion.

[Explanation of symbols]

 1 ... Fixed mold 4 ... Cavity side inner mold 8 ... Movable mold 9 ... Core side inner mold 10.10A ... Mold mounting plate (mounting plate) 11 ... Fixed mold 12 ... Back plate 14 ... First movable core 15 ... Vertically moving air cylinder 17 ... Communication hole 18 ... Second movable core 19 ... Horizontally moving air cylinder 20 ... Hollow part 22 ... Foam molding box 23 ... Undercut part

Claims (4)

[Claims] 1. A fixed die having a cavity side inner die, a core side inner die provided on the movable die, a fixed die, a first movable core for forming an undercut portion, and the fixed die. And a second intervening between the first movable core and
A movable core, the fixed die is fixed to a mounting plate provided on the movable die, the first movable core is connected to a vertically moving air cylinder provided on the movable die, and (2) A mold for a foam molding box having an undercut portion, wherein a movable core is connected to a left-right moving air cylinder provided on a back plate of the movable mold. 2. The molding die for a foam molding box with an undercut portion according to claim 1, wherein the first movable core has a forming portion that forms an inner and an outer portion of the undercut portion. . 3. The foam molded box having an undercut portion according to claim 1, wherein the second movable core has a hollow portion, and a communication hole is provided in the hollow portion. Molding die. 4. A fixed mold having a cavity side inner mold, a fixed mold of a movable mold, a first movable core and a second movable core are engaged with each other to form a core side inner mold. The movable mold is clamped to perform foam molding, and after the foam molding is completed, the second movable core is moved in the left-right direction, and then the first movable core is moved in the up-down direction. A method for molding a foam-molded box having an undercut portion, characterized in that a movable mold is opened.