JPH0530700B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for molding a lid of a container and a mold for the same, and more specifically, the present invention relates to a method for molding a lid of a container and a mold for the same. It prevents the containers from sticking together when stacking them, and it also improves the adhesion when fitting the lid onto the container, making it easy to mold while doing this, and it is also simple in the molding mold. This is related to the technology that is being developed.

[Prior Art] Conventionally, a lid made of a synthetic resin such as vinyl chloride or styrene and elastically fitted onto a vacuum-formed container has a lid as shown in FIG. A fitting protrusion 2 is provided around the outer periphery of the thin lid 1 made of resin, and a fitting groove 3 that is open downward is formed at the lower part of the fitting protrusion 2. The mouth edge portion 5 of No. 4 is elastically fitted. The side wall 6 of the fitting protrusion 2 is provided with a protrusion 12 at the upper and lower intermediate portions of the side wall 6, and this protrusion 12 is brought into elastic contact with the mouth edge 5 of the container 4, so that the lid 1 can be attached to the container 4. It is meant to be in close contact with the

[Problems to be Solved by the Invention] However, in this structure in which the protrusion 12 is brought into elastic contact with the mouth edge 5 to achieve close contact, the amount of protrusion of the protrusion 12 is increased to increase the adhesion force. However, if the size exceeds a certain level, it becomes difficult to release the protrusion 12 from the mold, and the amount of protrusion of the protrusion 12 can only be increased within the range in which release from the mold is possible. It has become difficult to significantly increase adhesion. Since the amount of protrusion of the protrusion 12 cannot be increased in this way, when the molded lids 1 are stacked, the lids 1 fit deeply into each other, making it difficult to remove the stacked lids 1 and making handling them troublesome. There were other problems. In other words,
Conventionally, the amount of undercut in the mold can only be increased to the extent that the molded product can be released from the mold, and this amount of undercut causes problems such as stacking problems and problems with adhesion to containers. It is something.

The present invention has been made in view of these problems, and its purpose is to form an undercut portion over the entire height of the side wall of the mating protrusion so that a large amount of undercut can be set. , when stacking lids during production, etc., it prevents them from sticking together, and when fitting the lid to the container, it improves the adhesion, and while doing this, it also prevents the molded product from being released from the mold. It is an object of the present invention to provide a method for molding a lid for a container, which allows easy molding, and a simplified molding mold, and a molding mold thereof.

[Means for Solving the Problems] The molding method of the present invention provides a thin lid 1 made of synthetic resin.
A fitting protrusion 2 is provided around the outer periphery of the fitting protrusion 2, and a downwardly open fitting groove 3 is formed at the lower part of the fitting protrusion 2. In this method of forming a lid of a container 4 that is elastically fitted, an undercut mold 9 is used to form a sloped wall surface 7 that is inclined inwardly or outwardly as it goes upward on the side wall 6 of the fitting protrusion 2.
After the molding, the undercut mold 9 is retired to the inside of the main mold 10 to release the molded product 11.

Further, in the molding die of the present invention, a fitting protrusion 2 is provided around the outer periphery of the thin lid 1 made of synthetic resin, and a fitting groove 3 that is open downward is provided at the lower part of the fitting protrusion 2. A mold for forming a lid of a container 4 in which a lip 5 of a container 4 is elastically fitted into a fitting groove 3, in which a fitting groove 2 is formed on a side wall 6 of the fitting groove 2. It is characterized in that an undercut mold 9 for forming an inclined wall surface 7 which is inclined inwardly or outwardly as it goes upward is configured to be freely retractable inside the main mold 10. be.

[Function] In this way, the inclined wall surface 7 which is inclined upwardly inwardly or outwardly is formed on the side wall 6 of the fitting projection 2 by the undercut mold 9, and after such forming, the undercut is formed. By retiring the undercut mold 9 to the inside of the main mold 10 and releasing the molded product 11, the undercut mold 9 can be moved inside the main mold 10 while increasing the amount of undercut. By retiring the molded product 11, it is possible to easily release the molded product 11 without being hindered by the undercut mold 9.

Further, the molding die of the present invention has a side wall 6 of the fitting protrusion 2.
By configuring the undercut mold 9 which forms the inclined wall surface 7 which is inclined inwardly or outwardly toward the fitting protrusion 2 upwardly to be retractable inside the main mold 10. By retiring the undercut mold 9 to the inside of the main mold 10 while increasing the amount of undercut, the molded product 11 can be easily released from the mold without being hindered by the undercut mold 9. It is possible to do this without changing the structure of the main mold 10 into a split mold while increasing the amount of undercut.
The configuration of the main mold 10 is simplified.

[Examples] Examples of the present invention will be described in detail below based on the drawings.

FIG. 1 shows a perspective view of the lid 1.
is a thin (for example, about 0.15 to 0.5 m/m) sheet material S made of synthetic resin such as vinyl chloride or styrene.
A fitting protrusion 2 is provided around the outer periphery of the lid 1, and a fitting groove 3 that is open downward is formed in the lower part of the fitting protrusion 2. A hanging piece 13 is suspended from the outer edge of the lid 1. A convex portion 16 is formed on the hanging piece 13 and projects inward. The container 4 is also vacuum formed from a synthetic resin sheet material S made of the same material as the lid 1. A mouth edge 5 having an inverted U-shaped cross section is formed at the outer edge of the container 4, and a horizontal ledge 29 is formed outside the mouth rim 5, and a hanging piece is attached to the outer edge of the horizontal ledge 29. Material 15 is hanging down. Although the lid 1 and the container 4 are made substantially transparent, they may be made opaque.

Thus, the fitting protrusion 2 of the lid 1 is fitted onto the inverted U-shaped mouth edge 5 of the container 4, and the lid 1 is fitted onto the container 4 to maintain airtightness.

Then, an inclined wall surface 7 is formed on the side wall 6 on the center side of the lid 1 among both side walls 6 of the fitting protrusion 2, and the inclined wall surface 7 is inclined inwardly as it goes upward, and the root part of the inclined wall surface 7 is largely hollowed out. An undercut portion 8 is formed in which the upper end of the inclined wall surface 7 overhangs.

In this way, by forming the inclined wall surface 7 on the fitting protrusion 2 to form the undercut portion 8, the amount of protrusion of the side wall 6 based on the inclined wall surface 7 is increased, and the fitting protrusion 2 is thus formed. By increasing the amount of protrusion of the side wall 6, when stacking the lids 1, it is possible to overlap the lids 1 at their large protruding parts (the second
(see figure), the side walls 6 do not come into close contact with each other as in the conventional case, and the lids 1 are prevented from coming into close contact with each other and stacked up. When performing work, etc., the lids 1 are not in close contact with each other, making the work easier.

Furthermore, the amount of undercut can be increased in the inclined wall surface 7, and the mouth edge 5 of the container 4 can be brought into closer contact with the container 4, thereby improving the airtightness of the container 4.

By the way, the opposing side wall 18 opposite to the inclined wall surface 7 of the fitting protrusion 2 of the lid 1 is also inclined substantially parallel to the inclined wall surface 7, and an undercut mold for forming the inclined wall surface 7 and the opposing side wall 18 is formed. It is designed so that 9 can be easily removed. The configuration of the molding die will be explained in detail below.

FIG. 4 shows a multi-cavity mold, and FIG. 5 shows one main mold 10. A main body mold 10 is integrally protruded from a flat base 19, and this main body mold 10 is composed of a lower part 20 and an upper part 21, and a large number of suction holes 22 are opened at appropriate locations. A resin sheet material S is connected to a vacuum pump (not shown) by piping and heated to an appropriate temperature and placed on top of the main mold 10, and is vacuum-formed by the suction action of the vacuum pump. Upper section 21
A fitting convex strip 2 is formed in the step, and a horizontal receiving step 17 and a hanging piece 14 can be formed in the lower step portion 20.

In the upper part 21 where the fitting protrusion 2 is formed, an undercut mold 9 is rotatably provided around a shaft 23, and an operating pin 26 is actuated via a connecting plate 25 by the operation of an air cylinder 24. By rotating the undercut mold 9 about the shaft 23, the undercut mold 9 can be freely changed between the protruding position shown in FIG. 7a and the retracted position shown in FIG. 7c.

In this way, by configuring the undercut mold 9 to be freely retractable inward of the main mold 10, the undercut mold 9 can be retired to the inside of the main mold 10 while increasing the amount of undercut. Thus, the molded product 11 can be easily released from the mold without being hindered by the undercut mold 9.

FIGS. 8 to 10 show other embodiments of the same as above, in which an inclined wall surface 7 is formed on the outer side wall 6 of the fitting protrusion 2, and the inclined wall surface 7 is inclined outward as it goes upward. The undercut mold 9 can be retracted into the main mold 10 in a sliding manner.

That is, as shown in FIG. 10a, the main mold 10
Return the undercut mold 9, which has been made slidable, and urge it to retire with the spring 27.
The undercut mold 9 is made to protrude by supplying air from an air pump (not shown). In such a case, as shown in Figure 10b,
The undercut mold 9 may be projected or retracted by rotating the rotary cam 28. When the undercut mold 9 protrudes and retires, the air drive source for vacuum forming may be shared. Such a configuration can be achieved by simply protruding the undercut mold 9 by suctioning air, and can be easily achieved by using a spring and piping configuration.

As shown in FIG. 13, an opposing side wall 18 facing the inclined wall surface 7 is suspended in a substantially vertical direction, and a convex portion 16 is formed on this opposing side wall 18.
A convex portion 5a may be formed on the inner wall of the mouth edge 2 of the container 4 as shown in FIG. ,
The shape and form can be modified in various ways, such as to enable tight fitting.

Further, the inclined wall surface 7 is preferably formed at the corner portion of the fitting protrusion 2 to increase the strength and adhesion at the corner portion.

[Effects of the Invention] In the molding method of the present invention, a fitting protrusion is provided around the outer periphery of a thin lid made of synthetic resin, and a downwardly open fitting groove is formed at the bottom of the fitting protrusion. A method of forming a lid for a container in which the lip of the container is elastically fitted into the fitting groove, and the side wall of the fitting protrusion is inclined inwardly or outwardly toward the top. The sloping wall surface is molded using an undercut mold, and after the molding, the undercut mold is retired to the inside of the main mold to release the molded product. By retiring the mold to the inside of the main mold, the molded product can be easily released without being interfered with by the undercut mold.

Further, in the molding die of the present invention, a fitting protrusion is provided around the outer periphery of the thin lid made of synthetic resin, and a fitting groove that is open downward is formed at the lower part of the fitting protrusion. A mold for forming a lid of a container in which the mouth edge of the container is elastically fitted into the fitting groove, the side wall of the fitting protrusion having an inclination that slopes upwardly inwardly or outwardly. The undercut mold for forming the wall surface is configured to be able to be retracted to the inside of the main mold, so by retiring the undercut mold to the inside of the main mold while increasing the amount of undercut. , the molded product can be easily released from the mold without being interfered with by the undercut mold, and the structure of the main mold can be improved without having to split the main mold structure while increasing the amount of undercut. can be simplified.

In the container lid formed according to the present invention, the amount of undercut can be increased to increase the amount of protrusion of the side wall based on the inclined wall surface, and thus the amount of protrusion of the side wall of the fitting protrusion can be increased. , when stacking lids, it is possible to overlap them at their large protruding parts, and the side walls do not come into close contact with each other as in the past, preventing the lids from coming into close contact with each other and overlapping, so that the lids can be stacked in close contact with each other. There is no
It can be easily handled, and the sloping wall surface on the side wall of the fitting convex strip allows for easy handling.
The amount of undercut can be increased, the container can be brought into closer contact with the mouth edge of the container, and the airtightness of the container can also be improved.

[Brief explanation of the drawing]

Figures 1a and b are a perspective view and a cross-sectional view showing an example of a lid molded by the molding method of the present invention, Figure 2 is a cross-sectional view of the same lid in a stacked state, and Figure 3 shows the same lid and container. FIG. 4 is a partially cutaway side view of the above molding device, FIG. 5 is a perspective view of the same mold, and FIG. 6 is the movement of the undercut mold. FIGS. 7a, b, and c are sectional views showing the forming action of the above, FIG. 8 is a partially cutaway side view of the forming apparatus of another embodiment of the above, and FIG.
The figure is a perspective view of the same mold as above, FIGS. 10a and 10b are cross-sectional views showing the movement of the undercut mold as above, explanatory views showing other drive forms as above, and FIGS. 11a,
b, c are cross-sectional views showing the forming action of the same as above, Fig. 12 is a perspective view of the lid formed by the same as above, Fig. 13 a,
b is a cross-sectional view showing another example of the lid, FIG. 14 is a cross-sectional view of a conventional lid and a container in a fitted state, and 1 is a lid;
2 is a fitting protrusion, 3 is a fitting groove, 4 is a container, 5 is a mouth edge, 6 is a side wall, 7 is an inclined wall surface, 8 is an undercut portion, 9 is a mold for undercut, 10 is a mold ,
11 is a molded product.

Claims (1)

[Scope of Claims] 1. A fitting protrusion is provided around the outer periphery of the thin lid made of synthetic resin, and a fitting groove that is open downward is formed at the lower part of the fitting protrusion. A method of forming a lid for a container in which the mouth edge of the container is elastically fitted, in which the side wall of the fitting protrusion is undercutted with an inclined wall surface that slopes inwardly or outwardly toward the top. 1. A method for molding a lid for a container, which comprises molding the product using a mold, and after the molding, retracting the undercut mold to the inside of the main mold to release the molded product. 2 A fitting protrusion is provided around the outer periphery of the thin lid made of synthetic resin, and a fitting groove that opens downward is formed at the bottom of the fitting protrusion, and the rim of the container is formed in the fitting groove. An undercut mold for forming a lid of a container into which a portion is elastically fitted, the undercut mold forming an inclined wall surface that slopes upwardly inwardly or outwardly on the side wall of a fitting convex strip. A molding die characterized in that the molding die is configured such that the lining can be freely retracted inward of the main die.