JPH01208116A - Manufacture of vessel having leg part - Google Patents

Abstract

PURPOSE:To reduce the cost of a vessel by simplifying a process, by a method wherein a formable plastic sheet is abutted against a molding surface of a female mold through a vacuum method or an air-pressure method and a part becoming the leg part of a plastic sheet is held by a protrusion molded on a male mold. CONSTITUTION:A foamable plastic sheet S is abutted against a molding surface 22 of a female mold 20 under gas pressure and a part of the sheet S is inserted into a recess 21 of the female mold 20. Then molding is performed so that a male mold 10 is approached to the female mold 20 and the inside of the sheet coincides almost with the inside of a vessel 40. Simultaneously with the above a part of the sheet inserted incompletely into a recess 21 with a protrusion 11 on the bottom of the male mold 10 is pressed forcibly into the recess 21. Then the part 42 of the sheet S in the recess 21 is held by a stepped part of the top close to the center part formed the recess 21 and the protrusion 11. Then an auxiliary mold 30 is moved forward toward the protrusion 11 and the sheet S is pressed so that the opposite side part 34 of the sheet S runs along a space between the protrusion 11 and an outside stepped part of the female mold 20.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to containers such as cups or trays formed from plastic sheets such as expandable polystyrene sheets (abbreviated as PSP), particularly containers having legs at the bottom thereof. The present invention relates to a manufacturing method.

(Prior Art) Containers such as cups and trays formed from plastic sheets 1 such as expandable polystyrene sheets have the following advantages: they can be mass-produced easily, they are cheap and disposable, and they are hygienic. This is because it has been used very frequently in recent years, and most of the common ones have a mole bottom. In this way, if the bottom of this type of container is flat, the heat of the food placed inside the container will be easily conducted to the outside through the bottom. In containers such as trays, it is difficult to hold the container in hand, and in containers such as trays that need to be kept cold, external heat is easily conducted from the bottom.

Therefore, various improvements have been made to form containers having legs at the bottom in order to block such heat conduction.

For example, in Japanese Patent Publication No. 39-19048.

In order to obtain a robust and stable container with a double wall at the bottom, as shown in Fig. A bottom mold smaller than the bottom of the do mold is installed at the bottom of the mold so that it can be raised and lowered, and the internal pressure during molding is used to form a double-walled part. A method for manufacturing a thermoplastic resin container characterized by forming a thick wall portion at the edge has already been proposed. By moving the bottom molds (5 pieces) upward, the thermoplastic resin sheet remaining within the annular plane (51) is folded double. However, the hf of the bottom mold (53) of this seat
In practice, it is difficult to reliably bend the container according to h, and the bottom surface of the double wall cannot form a uniform plane, and the bottom surface of the legs of the finished container is uneven, making it difficult to use as a container. This tends to result in a lack of stability.

As a conventional technology that seems to solve the above problems,
There is a method as disclosed in Japanese Patent Publication No. 62-57495. That is, this method will be explained with reference to No. 6 [4]. In this manufacturing method, the molds used in carrying out this method include a bottom molding mold (54), a pressure mold (56), and other molds. In this case, a total of four split molds, a main body (57) and a female mold (58), are required, and these must be configured to operate at a certain timing. In other words, in this manufacturing method, as the number of molds increases, the number of molds also increases, and as a result, it is difficult to obtain inexpensive containers.

Therefore, the present inventor proposed a method for inexpensively manufacturing a container having a flat inner bottom and legs on the outer bottom.
As a result of their research, they newly discovered that good results can be produced by actively holding the leg portions of the plastic sheet with male-shaped protrusions, and have completed the present invention.

(Problem to be solved by Problem III) The present invention was made based on the above-mentioned circumstances.
The problem to be solved is the complexity of the process in the conventional method for manufacturing a container with nine legs, and the high cost of the container due to this.

It is an object of the present invention to provide a manufacturing method that can manufacture a container having strong and stable legs through a continuous process and reduce the cost of the container formed thereby. It is about providing.

(Means and operations for solving the three problems) The means taken by the present invention to solve the following problem a will be explained with reference to FIGS. 1 to 4, which correspond to embodiments.

"N1. type (10" foamable plastic sheet (S)
) and a female mold (20) to produce a container (40) having legs (41) at the bottom through the first steps.

(a) Place the foam plastic sheet (S) into the female mold (2
The container (4) of the female mold (20) is brought into contact with the molding surface (22) of the female mold (20) by a vacuum method or a compressed air method.
0) Step of inserting a part of the plastic sheet (S) into the recess (21) corresponding to the leg (41) of the container (40): (B) For this female mold (20), insert the leg of the container (40) A male mold (10) having a protrusion (II) corresponding to the part (41).
), and a part of the plastic sheet (S) is made into a female mold (20) by a Ja-shaped (lO) protrusion (11).
further insert into the recess (21) of the protrusion (11) and the female y
! ! ! (20); (c) advancing the auxiliary mold (30) that has been retreated into the recess (21) of the female mold (20);
The protrusion (+1) of the male mold (10) is
) to press the other part of the plastic sheet (S) held on the female mold (20) side along the opposite side of the protrusion (11); S) is integrally molded into a container (40) using an M mold (10) and a female mold (20).

Next, this manufacturing method will be explained in more detail with reference to the drawings.

First, in the manufacturing method according to the present invention, a plastic sheet (S) to be a container (40), such as an expandable Bosty styrene sheet, is carried between a male mold (lO) and a female mold (20) by known means. At the same time, this plastic sheet (S) is heated by known means so that it can be easily molded, that is, it is softened. In addition, in the following explanation, pressurized gas is introduced into the plastic sheet (S) placed between the m-type (10) and the female mold (<20) in a softened state from one side as shown in the figure. The manufacturing method according to the present invention is a method in which air is sucked from the bottom of the Tamaki plastic sheet (S).
In other words, a vacuum forming method may be employed. and.

(a) The foamable plastic sheet (S) is heated by gas pressure onto the molding surface (
22) and a part of this plastic sheet (S) is inserted into the recess (21) of the female mold (20). In this case, the shape of the plastic sheet (S) in contact with the molded surface (22) has softened so that it almost matches the outer shape of the container (40); The portion corresponding to the leg portion (41) of 40) is not yet in a perfect shape. Therefore, as shown in FIG. Plastic sheet (S
) is molded so that the inner surface shown in the figure substantially coincides with the inner surface of the container W (40). At the same time, the plastic sheet (2) which had been inserted halfway into the recess (21) of the female mold (20) by the protrusion (II) integrally provided on the lower surface of the male mold (10) The - part of S) is forcibly pushed into the recess (21). As a result, the part (42) of the plastic sheet (S) that was inside the recess (21) forms the recess (21) of the female mold (20), as shown in FIG. It is held by the t-end step near the center and the protrusion (11). Note that the outer leg portion (43) of the plastic sheet (S) located on the right side of the projection (11) in the figure is still in a free state.

It is preferable that the protrusion (11) provided on the lower surface of the male mold (lO) is as thin as possible compared to the leg part (41) of the case W (40). This protrusion (11) is inserted into the part that will eventually become the leg part (4I) of the container (40) when the male mold (lO) and the female mold (20) are pressed as described later. This protrusion (11)
This is because it is necessary to ensure that no space remains within the legs (41) of the completed container (40). In addition, by using a foamable material such as expanded polystyrene as the plastic sheet (S), the space after the protrusion (11) is removed can be filled by secondary foaming of the material located around it. It is something that can be filled. Next, as shown in FIG. 4, (c) the auxiliary η which has been retreated into the recess (21) of the female mold (20)! (30) is advanced toward the protrusion (1+). Of course, the tip (31) of this auxiliary type (30)
is formed so as not to interfere with the protrusion (I+). That is, the tip (:lI) of this auxiliary type (30) is the fourth
[In the case of complete advance as shown in 4,
On the right side of the protrusion (11) and the plastic sheet (S
), and the plastic sheet (S
) so that the position is set back by about the thickness of the

As a result, the tip (31) of this auxiliary mold (30) is
When the auxiliary mold (30) is fully advanced, the plastic sheet ( The opposite part (43) of the male type (lO)
11) and the outer part of the female mold (20).

In addition, in order to facilitate the advancement of the auxiliary mold (30) and to prevent damage to the outer legs (43), this auxiliary mold (30) is
The tip (31) of 0) may be formed as a tapered or rounded portion.

Also, the auxiliary type (30) is female! The backing (32) is configured to slide against the IS (20) in an airtight manner. Furthermore, a plurality of auxiliary molds (30) are added to the female mold (20
) and are constantly moved backward while being biased by a sublink or the like, and a pressurizing cylinder (P) for advancing each of these auxiliary molds (30) is disposed in the female mold (20). By activating this pressure cylinder (P), each auxiliary type (30) can be activated at the same time, making it easy to produce multiple containers (40) each having legs (4). This is what makes IJF Noh possible.

As shown below, make a foam plastic sheet (
S) will almost match the container (1111) and the legs (41).Finally, (d) this plastic sheet (S) will be integrated with the male die (10) and the female die (20). By forming the
The container (40) has legs (4I).

This molding is generally necessary for secondary foaming of the plastic sheet (S).

As shown in Figure 1, a FAtff blade (I3) is formed in the - part of the AI mold (10), and the plastic sheet (S) is inserted between the male mold (10) and the female mold (20). When molding is performed, this cutting blade (13) cuts the plastic sheet 1-(S) into a predetermined shape at the same time as the molding, and cuts the container (4) into a predetermined shape.
0).

In addition, in the specific example described above, the tip (31) of the auxiliary mold (30) or the one formed so as to be located on the right side of the protrusion (11) shown in FIG.
.

Alternatively, the tip (31) may be placed on the left side of the protrusion (11). In this case, the protrusion (11
), the part (43) of the plastic sheet (S) shown in FIG.
Part (42) of plastic sheet (S) by 0)
The shape of the legs (41) should be adjusted as much as possible.

In the container (40) formed as above, its legs? 1B (41) or plastic sheet (S), it has higher rigidity than other parts, and this leg part (41) It also plays a role in suppressing heat conduction. Furthermore, the legs (41) of this container (40) are
The auxiliary mold (3) moves forward within the recess (21) of the female mold (20).
0), there are no irregularities on the lower surface of the legs (41), and when the completed container (40) is placed on a desk or the like, it will not wobble at all. It's something that doesn't exist.

(Effects of the Invention) As detailed above, in the present invention, [(a) the foamable plastic sheet (S) is applied to the molding surface (22) of the female mold (20) by a vacuum method or by compressed air. The legs 81 of this female type (20) container (40)
Step of inserting a part of the plastic sheet (S) into the recess (21) corresponding to K (41): (b) For this female mold (20), insert 11 of the container (40)
Male type (!l) with a protrusion (!l) corresponding to part 11 (41)
A1. ! ! ! A part of the plastic sheet (S) is further inserted into the recess (21) of the female W (2G) by the protrusion (11) of (10) and held by the protrusion (11) and the female mold (20). Step; (c) Advance the auxiliary mold (0) that has been retreated into the recess (21) of the female mold (20), and use the tip (31) of this auxiliary mold (0) to insert the male Protrusion (11) of mold (10)
Step of pressing the other part of the plastic sheet (S) held on the female mold (20) side along the opposite side of the protrusion (!l); (d) In the above state, press the other part of the plastic sheet (S) A process of integrally molding the entire body with a male mold (10) and a female mold (2o) to form a container (40). One of its characteristics lies in the fact that the container (4o) is manufactured, and as a result, a container having strong and stable legs can be manufactured using an hour wheel, and the container formed thereby can be Therefore, the cost can be reduced.

Namely, 1.For example, the special public interest 62-57495 mentioned in lti
In the molding method shown in the publication, the bottom mold (5
4), pressure mold (56), main body (57) and female mold (58)
), whereas the manufacturing method of the present invention requires the use of a total of four divided molds (10), a male mold (10) and a female mold (10).
20) and a female mold (20) + 7) to manufacture a container (40) having a leg part (41) with a total of three divided molds, an auxiliary mold (30) inserted into the recess (21). This makes it possible to simplify the manufacturing process compared to conventional methods, and also to reduce the cost of molds when implementing this method.

In addition, according to the manufacturing method of the present invention, the number of steps can be simplified as shown in I-A L, and it is also possible to produce a large number of containers in a short period of time. 40)
It is possible to mass produce multiple pieces at the same time. Originally, this type of disposable container (40)
When it comes to materials, the amount of material costs that make up the total price remains almost the same no matter what method you use, but rather how much it increases in a short amount of time! Since the cost is determined depending on how it is manufactured, the manufacturing method of the present invention is used.
-The fact that it is possible to actively reduce the divisor means that
This is a very big advantage in manufacturing this type of container (40).

Furthermore, according to the present invention, legs as reinforcing ribs can be easily formed not only for cup-shaped containers but also for rectangular so-called tray containers.

4.1′! Explanation of the hour wheel on page 11 Figure 1 is a partial vertical cross-sectional view of an apparatus for manufacturing containers with legs, and each of Figures 2 to 4 is an enlarged view of the main part of Figure 1 +g. FIG. 3 is a partially enlarged vertical cross-sectional view showing the manufacturing process according to the present invention in order.

Note that each of FIGS. 5 and 6 is a partial vertical sectional view showing a conventional apparatus for manufacturing a container having one leg.

Explanation of symbols 10--Male type, 11--Protrusion, 20--Female type, 2
1-... recess, 22... molding surface, 30... auxiliary mold,
31... Tip part, 40-... Container 41... Leg t3-
s-”・Plastic sheet.

From l- Figure 2 Figure 3 】○ Figure 4 55! :l')

Claims (1)

[Claims] A method for manufacturing a container having legs at the bottom by pressing a foamable plastic sheet with a male mold and a female mold through the following steps. (b) The foamable plastic sheet is brought into contact with the molding surface of the female mold by a vacuum method or a compressed air method, and the plastic sheet is placed in a recess corresponding to the leg of the container in the female mold. Step of inserting a part; (b) A male mold having protrusions corresponding to the legs of the container is moved relative to the female mold, and the protrusion of the male mold allows
further inserting a part of the plastic sheet into the recess of the female mold and holding it between the protrusion and the female mold; (c) advancing the auxiliary mold that had been retreated into the recess of the female mold; , using the tip of this auxiliary mold to press the other part of the plastic sheet held on the female mold side by the male protrusion so that it runs along the opposite side of the protrusion; (d) the above state; A step of integrally molding the entire plastic sheet using the male mold and the female mold to form the container.