JPS63281952A - Preparation of opening lid of simple opening can - Google Patents

Abstract

PURPOSE:To uniformize the thickness of a thin wall part and to prevent the leakage from a thin wall part carving part, by mounting a tab to a lid part and subsequently carving the annular thin wall part in the lid part while rotating said lid part. CONSTITUTION:A lid part 2 has such a cross-sectional shape wherein a protruding part 23 equipped with a projection as a tab 3 is formed to the center and a ridge 24 concentric to the protruding part 23 is formed to the outer periphery of said protruding part 23. In the case of the lid part 2 thus constituted, an annular bottom part 25 having a definite width is formed between the protruding part 23 and the ridge 24 and, after the peripheral edge of the lid part 2 is clamped to the open end part of a can container 1 by caulking, a cutting tool 4 is penetrated in the central part of the annular bottom part 25 while the can container 1 is rotated to carve an annular thin wall part in the bottom part 25. Since the cutting amount of the lid part in the wall thickness direction thereof is determined by the penetration depth of the cutting tool, said cutting amount becomes constant in the processing region of the lid part in the wall thickness direction so far as the lid part 2 rotates on one plane or cylindrical surface. As a result, the irregularity in the thickness of the thin wall part becomes hard to generate.

Description

[Detailed Description of the Invention] [Field of Application] The present invention relates to an easy-to-open can, particularly a type of easy-to-open can that is opened by pulling apart an opening part formed on the lid of a can container and surrounded by a thin wall part using a tab. This invention relates to a method for manufacturing an opening lid for an opening can, in which a ring-shaped thin wall portion is formed on a lid portion on which a tab is formed so as to surround the tab, and this thin wall portion is formed by cutting. This is to make the wall thickness of the part uniform and to prevent cracks from forming in this thin part.

[Prior Art and Problems Therewith] As an easy-to-open can of the type in which the opening part formed on the lid of the can container and surrounded by a thin wall part is pulled apart by a tab to open the can, there is a cap on the top of the can container (1). A concave groove using plastic deformation by press working is carved on the surface side of the attached lid part (2), and this part is made into a thin wall part (21), and an opening surrounded by this thin wall part (21) is formed. Part (22
) has already been disclosed in Japanese Utility Model Publication No. 1983-524, in which a portion of the tab (3) is glued near the periphery of the tab (3).

(See Figures 5 and 6) In this conventional type, the lid part (21) is formed with a thin wall part (21).
Since the tab (3) is attached to the opening part (22) of 2) by adhesive, cracks are less likely to occur in the thin wall part (21), that is, the conventional example in which the tab (3) is attached by caulking. In the case of the previous can containers, uneven external force acts on each part of the thin-walled part (21) that has already been engraved during the caulking process, causing cracks in some of the thin-walled parts (21). However, in the conventional type, since the tab (3) is attached to the opening part (22) by adhesive, harmful external forces such as tension are applied to the thin wall part (21) during this attachment. Therefore, the occurrence of cracks due to the above-mentioned reasons can be prevented.

However, in this conventional method, the thickness of the thin wall portion (21) tends to be uneven, and when carving the thin wall portion (21), an extremely thin wall portion that is a cause of cracks is likely to occur. Due to reasons such as progression of corrosion when stored for a long time while the contents are stored, and cracks occurring in the ultra-thin portion when impact force is applied during transportation, etc., the contents should be removed from this part. may leak.

When the thin wall portion (21) has a non-circular shape and a recess is stamped on the surface of the lid portion (2) by press working, the pressing force between the stamping mold and the unprocessed member is This is because it is difficult for the stamping method to be uniform, and furthermore, even if the stamping die is partially deformed slightly, that deformation will appear as a variation in the stamping method.

[Technical Section B] The present invention is directed to the “thin wall portion provided in the lid portion (2)”.
In the easy-to-open can 1 of the type in which the tab (3) is attached to the opening part (22) surrounded by the thin wall part (21)
In order to prevent leakage from the engraved part,
The technical problem is to make the thickness of the thin part (21) uniform over the entire area.

[Technical Means] The technical means of the present invention taken to solve the above-mentioned technical problems include the first step of attaching the r-tab (3) to the lid (2), and the step of attaching the r-tab (3) to the lid (2) after this step. 2) is provided with a second step of carving an annular thin-walled portion (21) by cutting into the rotating surface in a direction perpendicular to the rotating surface while rotating the rotating surface.

[Effect] The above technical means of the present invention operates as follows.

The tabs (3) are already attached when the thin-walled portions (21) are carved. In this state, the lid (2) is rotated, and the cutting tool is bitten into the rotating surface in a direction perpendicular to the rotating surface, thereby carving a thin portion (21) on the surface of the lid (2). As a result, a circular thin section (
21) will be engraved. At this time, the lid (2)
The amount of cutting in the thickness direction of the lid (2) is determined by the depth of penetration of the cutting tool. is constant in the processing area. As a result, the thin part (2
1) The variation in wall thickness is less likely to occur.

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

Variations in the thickness of the thin wall portion (21) carved into the lid portion (2) are less likely to occur, and therefore the thin wall portion (21) does not become locally extremely thin, preventing corrosion during long-term storage. Partial damage due to the application of impact force during movement or movement will not occur.

In addition, in the conventional method described above, a corrosion-preventing film or a corrosion-resistant layer was specially formed on the inner surface of the lid part (2) to prevent leakage caused by the corrosion, but in the case of the method of the present invention, In this case, there is no need to apply a special corrosion-preventing coating to the inner surface of the lid (2), and a corrosion-preventing treatment layer provided on the constituent material of the lid (2) is sufficient. Therefore, the manufacturing process of the easy-to-open can can be simplified.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

The first embodiment shown in Figs. 1 and 2 has a can container (1
) is a cylindrical body with a bottom, and a lid (2) is caulked to the open upper end thereof, and a thin wall portion (21) is carved after the lid (2) is caulked.

As shown in FIG. 1, the cross-sectional shape of the lid part (2) has a raised part (23) having a protrusion as a tab (3) in the center, and a raised part (23) concentric with the raised part (23) on its outer periphery. The ridges (
24).

In the case of the lid part (2) configured in this way, the raised part (23)
An annular bottom (25) with a constant width is formed between the ridge and the protrusion (24), and the periphery of the lid (2) is connected to the can container (1).
After caulking the open end of the can, as shown in Fig. 2, while rotating the can container (1), insert the cutting tool (4) into the center of the annular bottom (25), as shown in Fig. 1. An annular thin-walled portion (21) is carved in the area.

In addition, the thickness of the thin wall portion (21) is as follows: When the material of the lid portion (2) is made of aluminum with a thickness of approximately 0.5 ml, the wall thickness of the thin wall portion (21) is as follows. , 0.1 am
In the case of a can container manufactured in this way, when the tab (3) is pushed down from one side, the area surrounded by the thin wall portion (21) will be Since it is separated from the outer periphery, it can be opened easily. In this case, the range up to the vicinity of the outer periphery of the raised portion (23) becomes the opening portion (22), and after opening, the protruding strip (24) protrudes from the outer periphery of the opening, and the can container ( 1) When food and drink are stored inside, the cut of the opening part is protected by this protrusion (20).Therefore, there is no risk of cutting your lips by the cut of the opening part when eating or drinking. .

Next, in the second embodiment shown in FIG. 3, the lid part (2) is formed integrally with the can container (1), and the bottom part of the can container (1) is formed by a separate bottom plate (lO). It is designed to be closed.

In this embodiment as well, the cross-sectional shape of the lid portion (2) is configured in the same manner as in the first embodiment, and a thin wall portion (21) is carved in the annular bottom portion (25). This thin part (21
) may be done as a step after closing the bottom of the can container (1) with the bottom plate (10),
1), the thin-walled portion (21) can be carved prior to installation. Therefore, it is only necessary to select which of the above two aspects to adopt in relation to other processes.

In addition, the thin part (21) has a tab (3) as shown in FIG.
) may be engraved at the base of the
The cutting tool will bite into the rotating curved surface in a direction perpendicular to it.

In the easy-to-open cans manufactured in this way, the tab (3)
When pushed to one side, only the tab (3) is separated from the lid (2) and the bag is opened.

In each of the above embodiments, the tab (3) is connected to the lid part (2).
), but the tab (3) may be constructed separately from the lid (2) and attached to the lid (2) by caulking or adhesive.

Moreover, as shown in FIG. 7, when the bottom plate (10) is caulked to the lower end of the can container (1), if the bottom plate (lO) is rolled up to the inner circumferential side, the can container (1), (1)
There will be no unnecessary gaps between them.

[Brief explanation of the drawing]

Claims (1)

[Claims] In an easy-to-open can of the type in which a tab (3) is attached to an opening part (22) surrounded by a thin-walled part (21) provided on the lid part (2), there is a first part in which the tab (3) is attached to the lid part (2). After this step, a second step is performed in which an annular thin-walled portion (21) is carved by cutting the lid portion (2) in a direction perpendicular to the rotating surface while rotating the lid portion (2). A method for producing an opening lid for an easy-to-open can.