JPS6345941B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to a method for manufacturing a novel case used for packing cassette tapes, video tapes, etc.

Conventionally, the manufacturing method for this type of case was to
An outer sheet 30 made of a thermoplastic soft synthetic resin and an inner sheet 30' made of the same are polymerized on both upper and lower surfaces of a cardboard core formed from the back and lid parts, and these outer sheets 30,
After the entire periphery of the inner sheet 30' is welded to each other around the outside of the cardboard core, the case main body 6 and the lid frame 7 are placed on the inner sheet 30, and the outward flanges 25, 25 are attached to the same inner surface. sheet 3
There is a known method for obtaining a finished product (see Figure 5) by welding the paper onto a cardboard core using a welder.
The process is complicated and has poor workability, and the inner sheet 30 made of thermoplastic soft synthetic resin is present over the entire surface under the case body and under the lid frame, making the whole heavy. Not only are there defects, but there are also problems such as the waste of the inner sheet (material) corresponding to the amount of defects, which is uneconomical.

In order to solve such problems, the present invention includes a step of polymerizing a cardboard core formed of a bottom, a back, and a lid that are continuous on the upper surface of a thermoplastic soft synthetic resin outer sheet via a bendable line; A step of polymerizing a thermoplastic soft synthetic resin cover sheet having a size that covers only the narrow width area near the back of the bottom and lid part and the entire back of the cardboard core on the back of the cardboard core, the bottom of the cardboard core. and a step of superimposing a dish-shaped case body and a lid frame body, which are integrally formed with an outward flange around the entire circumference of the lower edge obtained by press-drawing a thermoplastic hard synthetic resin plate on the lid part, the case body and the lid frame body. At the outer flange of the body and at the periphery of the outer sheet, the points corresponding to the outer flange, and at both edges of the cover sheet and at the periphery of the outer sheet, the points corresponding to both edges of the cover sheet are placed around the outside of the cardboard core. Another object of the present invention is to provide a method for manufacturing a case, which comprises sequentially welding the outward flange and both side edges of the cover sheet onto a cardboard core using a welder.

Next, embodiments of the present invention will be described with reference to the drawings. First, an outer sheet 23 made of thermoplastic soft synthetic resin will be described.
A bottom portion 20 that is continuous to the top surface of the
A cardboard core formed from a back portion 21 and a lid portion 22 is polymerized.

Next, on the back part 21 of the cardboard core, a cover sheet made of thermoplastic soft synthetic resin is sized to cover only the narrow width area near the back part 21 in the bottom part 20 and the lid part 22, and the entire surface of the back part 21. Polymerize 24.

Further, a dish-shaped case main body 6 and a lid frame body are provided, which are formed by pressing and forming a thermoplastic hard synthetic resin plate on the bottom part 20 and lid part 22 of the cardboard core, and integrally have an outward flange 25 around the entire lower edge thereof. Polymerize 7.

Thereafter, the parts corresponding to the outward flanges 25, 25 and the outer sheet 23 on the case body 6 and the lid frame 7 and the outer sheet 23, and both end edges of the cover sheet 24 and the outer sheet 2 are removed.
3, the areas corresponding to both edges of the cover sheet 24 are placed around the outside of the cardboard core, and the outward flanges 25, 25 and both side edges of the cover sheet 24 are placed on the cardboard core by welding. The finished product can be obtained by wearing the cloth.

Incidentally, the case body 6 and the lid frame 7 are provided with a fitting protrusion 10 and a concave fitting edge 11 on the opening edges 8 and 9 of the case body 6 and the lid frame 7 during the drawing process. 10 is provided with a notch 12, and the opening edge 8 provided with the same fitting protrusion 10 is provided with a concave notch 13 continuous to the notch 12,
In addition, the above-mentioned notch 1 is formed on the bottom surface of the fitting concave edge 11 when the lid is closed.
2 and a protrusion 14 that fits into the recess 23, respectively, so that the lid and the body are brought into close contact when the lid is closed.

Since the present invention is as described above, it goes without saying that the process is simpler and the workability is much better than the conventional method described above, but in particular, the finished product obtained by the present invention is Since the lower part does not have an inner sheet as in the finished product made by conventional methods, it is not only suitable and preferable when a heavy and light product is required, but also because the material is at least good. This has excellent effects such as greatly contributing to the realization of cost reduction.

[Brief explanation of drawings]

The figures show an embodiment of the method for manufacturing a case of the present invention, in which Figure 1 is a perspective view showing the entire finished product, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is a cross-sectional view taken along the line A-A in Figure 1.
The figure is an exploded perspective view of the whole, FIG. 4 is a sectional view showing the manufacturing process of the present invention, and FIG. 5 is a sectional view of a finished product produced by a conventional method. 1... Back plate, 2... Flexible part, 3... Bottom plate,
4...Bendable part, 5...Lid plate, 6...Case body, 7...Lid frame body, 8, 9...Opening edge, 10...
Fitting protrusion, 11... Fitting concave edge, 12... Notch, 1
3...Concave notch, 14...Protrusion, 20...Bottom, 2
DESCRIPTION OF SYMBOLS 1...Back part, 22...Lid part, 23...Outer sheet, 24...Covering sheet, 25...Outward flange.

Claims (1)

[Claims] 1. A step of polymerizing a cardboard core formed by a bottom, a back, and a lid that are continuous on the top surface of a thermoplastic soft synthetic resin outer sheet via a bendable line. A process of polymerizing a thermoplastic soft synthetic resin cover sheet of a size that covers only a narrow width area near the back and the entire back, and a thermoplastic hard synthetic resin plate is placed on the bottom of the cardboard core and the lid. The step of polymerizing the dish-shaped case body and lid frame body, which have an outward flange integrally around the entire circumference of the lower edge obtained by pressure drawing, At the point corresponding to the outward flange, at both edges of the cover sheet and at the periphery of the outer sheet, at the point corresponding to both edges of the cover sheet, at the outer circumference of the cardboard core, and at both edges of the outward flange and the cover sheet. A method for producing a case, comprising sequentially welding each of the two on a cardboard core using a welder.