JPH0481447B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application] The present invention relates to a method of manufacturing a bag made of synthetic resin, and particularly to a method of manufacturing a bag such as an attache case having a rigid exterior plate. In a type of bag in which the bag halves are brought together at their open ends, the outer surface of the frame-shaped portion at the open ends of the halves is not inclined but is parallel to the opening direction of the halves over almost the entire area. The purpose is to create an appearance composed of flat planes. In addition, as a method for this purpose, by devising the mold structure during injection molding, it is possible to mold the product into the above-mentioned shape at the end of injection molding.

[Prior Art and Problems Therewith] Attachment cases have been widely used as business bags because their exterior parts have sufficient rigidity, so that the contents are sufficiently protected against impact forces.

This type of bag is constructed from a combination of metal plates and synthetic resin molded products, but because it is designed to be easy to use, such as by being equipped with an internal pocket, it is more expensive than a simple bag. It has become a thing.

From the viewpoint of protection against impact, it is also possible to manufacture the entire structure by injection molding of synthetic resin, as shown in FIG. In the product manufactured in this way, half 1 of the dish-shaped main body including the handle 2
Since parts a and 1b can be manufactured simultaneously and integrally by injection molding, a bag similar to a so-called attachment case is completed upon completion of injection molding. Therefore,
This type of bag can be manufactured at low cost.

However, bags manufactured using this method have an unsightly appearance.

This is because in the injection mold, it is necessary to take into account the draft angle (the slope of the surface that is provided to take out the product from the mold after injection molding and is inclined in the direction of taking out the product). In the case of the method of manufacturing 1b, as shown in FIG. 13, it is necessary to provide a draft slope on the surface of the frame-shaped part 11 formed at the periphery of the open end of one half 1a, and in the completed state, The surface of the frame-shaped part 11 having this draft appears as it is in the external appearance, and the inclined surface is the surface of the frame-shaped part 11.
This is because it is continuous on the surface of the case, giving it an uncluttered image when compared to a normal attachment case.

[Technical Problem] The present invention is directed to such a “frame-shaped portion 1 at the open end portion”.
1, and a dish-shaped half 1b, which has an open end that fits into the frame portion 11 and is approximately symmetrical to the half 1a, at its lower side. In the method for manufacturing a synthetic resin bag in which the bags are bendably connected to each other by connecting pieces 3 and the entire bag is integrally molded by injection molding of synthetic resin, the open ends of half body 1a and half body 1b The technical problem is to make the draft angle of the outer circumferential surface of the frame-shaped part 11 inconspicuous so that the outer circumferential surface of the mutually overlapping parts has the same image as a conventional attachment case. .

[Technical Means] The technical means of the present invention taken to solve the above-mentioned technical problem is similar to the half body 1a in which the half body 2a of the handle 2 is integrally connected to the center of the upper side of the open end. A half body 1b, in which the other half part 2b of the handle 2 is connected to the half body 1a at a symmetrical position of the half body 1a at the center of the upper side of the open end, is arranged side by side so that the constituent planes of the open end edges are parallel to each other. In order to perform injection molding with the lower sides of the half bodies 1a and 1b connected to each other by the bendable connecting piece 3, a cavity and a core of an injection mold are manufactured, and the outer surface of the frame-shaped part 11 is In the mold configuration surface on the cavity side corresponding to the above, and in the flat part between the upper corner part of the frame-shaped part 11 and the half part 2a and between the side corner parts, with respect to the mold dividing direction. Slide cores 4, 4 that can be retracted and retracted in the right angle direction are arranged, and the end surfaces 41 of the slide cores 4, 4 on the product surface side are configured to be planes parallel to the dividing direction of the mold, and the width of the end surfaces 41 is The width of the frame portion 11 is set smaller than that of the frame portion 11, and the width of the end surface 41 and the frame portion 11 are set to be smaller than the width of the frame portion 11.
is made to slightly protrude from the surface of the cavity corresponding to the frame-shaped portion 11, and is injection molded using a mold having the above-mentioned configuration.

[Function] The above technical means of the present invention works as follows.

According to the method of the present invention, when injection molding is performed using an injection mold, the mold includes a half body 1
a, 1b, half portions 2a, 2b, and a portion corresponding to the connecting piece 3, a synthetic resin bag is completed.

Particularly, regarding the frame-shaped part 11 of the half body 1a, the mold has a part corresponding to the frame-shaped part 11,
Since the slide cores 4, 4 are placed in the parts other than the corner parts and the half part 2a, and the end faces 41, 41 are in a state slightly protruding within the cavity, the surface of the frame part 11 in the completed state is A predetermined range other than the corner portions and the half body portion 2a is formed into a flat surface, and this flat surface is parallel to the opening/closing direction of the bag.

Therefore, although the parts other than the parts corresponding to the end faces 41, 41 are finished with a draft angle required during injection molding, the area of the flat part is extremely larger than that of the draft part. Because it becomes a real object, the dominant influence of this draft on the appearance disappears.

[Effects] Since the present invention has the above configuration, it has the following unique effects.

On the surface of the frame-shaped part 11 and at the corner part and the half part 2
A predetermined area other than the part a is molded into a flat surface, and this flat surface is parallel to the opening/closing direction of the bag, and the area of this flat part is a part with a draft angle required during injection molding. Since the area of the draft is extremely larger than the area of the draft, the appearance control power of this draft is lost. Therefore, the appearance is the same as if the maximum outer circumference of the bag in the completed state was composed of a plane parallel to the opening direction of the bag, and it is possible to prevent the conventional problem of a so-called loose appearance. .

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 11.

The bag manufactured according to this embodiment has a structure as shown in FIGS. 1 to 7, in which half body 1a is integrally formed with half body part 2a, and half body part 1b is integrally formed with half body part 2b. The outer shape of each half body 1a and 1b is approximately rectangular. The lower sides of the halves 1a and 1b are connected to each other by a connecting piece 3.
This connecting piece 3 has a thin wall and is flexible.

Next, a frame-shaped portion 11 is formed at the open end of the half body 1a, and both ends of the half body 2a are
It is configured to be continuous with this frame-shaped portion 11.
Further, on the surface of this frame-shaped portion 11, first recesses 12, 12 are provided on the sides, and second recesses 13, 12 are provided on the upper side.
13 is formed, and the second recessed portions 13, 13 are formed on further outer portions of the engaging pieces 5, 5 formed at both ends of the half body portion 2a.

The first and second concave portions 12 and 13 are both configured to have a plane parallel to the opening direction of the half bodies 1a and 1b, and the corner portions 14 and 14 and the lower side of the frame portion 11 are formed in a plane parallel to the opening direction of the half bodies 1a and 1b. It is an inclined surface with a slope corresponding to the slope, and the direction of this slope increases toward the open end of the half body 1a.

Further, the engaging pieces 5, 5 correspond to engaging protrusions 51, 51 provided on the half body 1a in a freely engaging and detachable manner, and each engaging piece 5 has a thin hinge at the base end of the frame-shaped portion 11. They are swingably connected via a portion 52, and an engagement hole 53 is opened at a position corresponding to the engagement protrusion 51. Further, in the frame-shaped portion 11, a notch 15 cut from the open end of the half body 1a is formed at a position corresponding to the engagement protrusion 51, and a notch 15 is formed near the open end of the half body 1b. The engagement protrusion 51 is adapted to fit into the notch 15 exactly. Further, a protrusion 16 is partially formed in the center of the notch 15, and this protrusion 16
is a side wall of the engaging protrusion 51, which is adapted to fit into a fitting recess 53 that opens toward the open end of the half body 1b.

The bag configured in this manner can be injection molded using a mold configured as shown below.

The mold used to manufacture the bag with the above structure consists of a male mold P serving as the core side and a female mold D serving as the cavity side. The mold structure for molding the main parts of the halves 1a and 1b is as shown in FIG. 8.

That is, since the connecting piece 3 is arranged at a position that coincides with the edge of the frame-shaped part 11 when the half bodies 1a and 1b are fitted into each other, the connecting piece 3 corresponds to the above-mentioned fitting depth. Cavities and core portions corresponding to the half bodies 1a and 1b are formed to have a step, and a parting surface corresponding to the open end of the half body 1b and an edge of the open end of the half body 1a, that is, the edge of the frame-shaped portion 11. As shown in the figure, the parting surface corresponding to the above-mentioned parting surface has a step corresponding to the fitting depth. Thereby, when the male mold P is made to face the female mold D and injection molding is performed, the half body 1a and the half body 1b can be integrally molded at the same time.

As shown in FIG. 8, slide cores 4 are disposed in portions corresponding to part of the side and upper sides of the frame portion 11, and in the mold of this embodiment, A portion corresponding to the first concave portion 12 and second concave portion 13 formed and a portion corresponding to the protrusion on the open end side serve as an end surface 41 of the slide core 4. Therefore, at the time of completion of injection molding, the surfaces of the first concave portion 12 or the second concave portion 13 and the protruding portion of the open end following this concave portion are in a plane parallel to the opening direction of the half body 1a and the half body 1b. becomes. In other words, the plane is perpendicular to the parting surface.

Next, the engaging piece 5 has a structure as shown in FIG. 9, and has a half body 1a and a half body 1b.
It is formed at a position extending from the open end by a distance corresponding to the depth of engagement with the opening end.
Further, in this embodiment, in order to make the engaging piece 5 bendable, its base end and the outer peripheral surface of the half body 1a are connected by the hinge part 52, and the frame-shaped part 11
It is designed to be molded in an upright position. Therefore, as shown in FIG. 9, the mold structure is such that only the portion corresponding to the engaging piece 5 protrudes from the core side to the cavity side. By employing this configuration, the engagement piece 5 is integrally molded with the half body 1a and is connected to the half body 1a in a flexible manner.

Next, a portion corresponding to the engaging protrusion 51 is constructed as shown in FIG. 10, and a mold is constructed in the same manner as the corresponding portion of the engaging piece 5. Thereby, similarly to the case of the engagement piece 5, the engagement protrusion 51 is also integrally molded in a state in which it projects in a direction perpendicular to the peripheral portion of the half body 1b.

Note that the half parts 2a and 2b can be manufactured using a normal mold structure.

When injection molding is performed using the mold configured as described above, the frame portion 11 of the half body 1a and the open end of the half body 1b fit together as shown in FIG. The handle 2, the engaging pieces 5, 5, and the corner portion 14 on the outer periphery of the fitting portion of the half body 1b, and the first and second recessed portions 12, 13 formed by the end surface 41 in the portion excluding the bottom portion. , and furthermore, the rib plane 10 on the edge side of the frame-shaped part 11 that is parallel to this plane part appears, and most of the range of the frame-shaped part 11 located in the center of the bag becomes half 1a. and half body 1b
This is a flat surface parallel to the opening direction, that is, a flat surface perpendicular to the central cross section.

At the same time, everything required for the bag, such as the opening/closing hinges of the halves 1a and 1b and the locking devices for both, are integrally molded at once.

As the synthetic resin material used in the method of the present invention, a material with high elasticity and flexibility, such as polypropylene resin, is effective.

[Brief explanation of the drawing]

Fig. 1 is a front view of a bag manufactured by the method of the present invention, Fig. 2 is a side view thereof, and Fig. 3 is a plan view.
Fig. 4 is a detailed view of the engaging piece 5, Fig. 5 is a bottom view, Fig. 6 is a sectional view taken along A-A, Fig. 7 is a sectional view taken along B-B, and Fig. 8 is used for manufacturing bags. 9 is a sectional view of a portion of the mold corresponding to the engaging piece 5, FIG. 10 is a sectional view of a portion corresponding to the engaging protrusion 51, and FIG. 11 is a completed product. 12 and 13 are explanatory diagrams of the conventional example, and in the figure, 11...frame-shaped portion, 1a, 1b...half body , 2...
Handle, 2a, 2b...Half part, 3...Connection piece, 4
...Slide core, 41...End face.

Claims (1)

[Claims] 1. A rectangular dish-shaped half body 1a having a frame-shaped part 11 at an open end, and a dish-shaped half body 1a having an open end that fits into the frame-shaped part 11 and approximately symmetrical to the half body 1a. In a method of manufacturing a synthetic resin bag, the lower sides of the halves 1b are connected to each other in a flexible manner by a connecting piece 3, and the whole is integrally molded by injection molding of synthetic resin. A half body 1a has a half body 2a of the handle 2 integrally connected at the center of the upper side, and the other half body 2b of the handle 2 is similarly connected at a symmetrical position of the half body 1a at the center of the upper side of the open end. The half bodies 1b are arranged side by side so that the constituent planes of their open edges are parallel to each other, and the lower sides of the half bodies 1a and 1b are mutually connected by a bendable connecting piece 3, and then injection molded. In order to achieve this, a cavity and a core of a mold for injection molding are manufactured, and the mold forming surface on the cavity side corresponding to the outer surface of the frame-shaped part 11 and the corner part of the upper side of the frame-shaped part 11 and the half-body part 2a are Slide cores 4, 4 that can be retracted and retracted in a direction perpendicular to the mold dividing direction are arranged on the plane between the corner parts of the sides and between the corner parts of the sides, and The end face 41 is configured to be a plane parallel to the dividing direction of the mold, and the width of the end face 41 is set smaller than the width of the frame-shaped part 11, and the end face 41 is positioned in the middle of the frame-shaped part 11 in the width direction. Furthermore, the end surfaces 41, 41
A method for producing a synthetic resin bag, in which the bag is made to slightly protrude from the surface of the cavity corresponding to the frame-shaped part 11, and injection molded using a mold having the above configuration.