JPS6068120A - Can making method - Google Patents

Abstract

PURPOSE:To obtain perfect airtightness by superposing the outside circumferential edge part of a cap plate to the opening end edge part of a can body and welding fully circumferentially the end edges of both parts to each other then bending the superposed end edge parts to the outside or inside of the can body. CONSTITUTION:An opening end edge part 6 of a can body 1 formed to a cylindrical shape is bent to a flat flange shape and the outside circumferential end part 7 of a flat plate-shaped cap plate 2 is folded then a flat flange part 7b is formed to the tip of the folded part 7a. The part 7 is superposed on the part 6 and the end edges of the body 1 and the plate 2 are welded over the entire circumference to each other by a welding machine 8. The superposed end edge parts 6, 7 of the body 1 and the plate 2 are bent integrally toward the outside of the body 1 by a curling roll or the like to make preferably a weld zone 9 hardly visible. The can body and the cap plate are thus securely joined and the airtightness is thoroughly assured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing metal cans, and more specifically, a can manufacturing method characterized by means for fixing a lid plate to at least one of the upper and lower open ends of a can body formed into a cylindrical shape. Regarding.

FIG. 1 shows an example of a metal can to which the present invention is applied, in which 1 is a can body, 2 is a bottom lid plate fixed to the lower opening edge of the can body 1, and 3 is an upper part of the can body 1. This is an upper lid plate that is detachably attached to the edge of the opening. Conventionally, in such metal cans, the second
As shown in the figure, a lid plate 2 is fixed to a can body 1 by winding. The same applies to the case where the upper lid plate 3 is integrally fixed to the can body 1. Although a sealing material 4 such as a packing or adhesive is used for this type of tightening, there is still a problem in terms of airtightness.

Focusing on the fact that this invention is unique, when fixing the lid plate to the body of a can, the aim is to make the appearance almost the same as the conventional one, and to ensure perfect airtightness. The feature is that the outer peripheral edge of the lid plate is overlapped with the opening edge of the can body formed into a cylindrical shape, and then the edges of the six FF are welded around the entire circumference.
Next, the overlapped edge portions of the can body are bent to the outside or inside of the can body.

The target can body 1 is a rectangular plate material made of a tin plate or the like, joined at both ends to be formed into a cylindrical shape in advance. Generally it is cylindrical, but the angle is ↑,? It may be i-shaped. It is desirable that the joints at both ends of the sheet metal forming the can body 1 be seam welded.

Adhesion or sealing may be used, and this point is not particularly limited.

Further, although the present invention is most effective when used to fix the bottom cover plate 2 to the can body 1, it can also be applied to the case where the upper cover plate 3 is fixed to the can body 1. As an extreme example, it is also effective to apply the present invention to the case where the contents are poured into an existing can in which the bottom cover plate 2 is tightly wound around the can body 1, and then the upper cover plate 3 is fixed.

When carrying out the present invention, it is possible to consider the case where the can body 1 is a tapered can, but this is generally vertical, whereas the lid jfj
, (2 or 3) is generally flat.

In this state, the outer peripheral edge portion of the lid plate cannot be overlapped with the opening edge portion of the can body 1. Therefore, it is necessary to bend the edge portions of one or both of the can body and the lid plate prior to welding, and then make sure that the edges of both are preferably flush with each other.

In addition, in actual can bodies, the inner surface including the lid plate is generally subjected to anti-rust treatment, and the outer surface is printed. Therefore, in order to overlap the outer circumferential edge of the lid plate on the open edge of the two can bodies and then weld the edges of both together over the entire circumference, laser welding is required instead of electric resistance welding.
Electron beam welding.

It is desirable to be able to perform welding using high-frequency welding or the like regardless of the presence of a non-conductive layer such as the above-mentioned rust prevention treatment or printing treatment. However, since the metal surfaces of the two can bodies and the edges of the lid plate are exposed, resistance welding is also possible.

Next, some of the embodiments will be explained in order.

FIRST EMBODIMENT FIGS. 3 and 4 show a first embodiment of the present invention, in which a can body 1 is formed into a cylindrical shape in advance, with the lower opening edge portion 6 facing outward and being horizontal. It is bent into a flat flange shape. and.

Lid Plate 5 Fixed to Can Body 1 In the figure, the bottom lid plate 2 is basically in the shape of a circular flat plate, but the outer peripheral edge portion 7 of the lid plate 2 is bent downward at a right angle.

A horizontal flat flange portion 7 is provided at the tip of this bent portion 7a.
b is formed by bending it outward.

In the method of the present invention, the can body 1 and the lid plate 2 having the above-described shapes are prepared, and first, as shown in FIG. 3, the outer peripheral edge portion 7 of the lid plate 2 is overlapped with the opening edge portion 6 of the can body 1. In the figure, cover plate 2
The bent portion 7a of the outer peripheral edge portion 7 is in close contact with the inner surface of the straight wall portion of the can body 1, and the flange portion 7b is in close contact with the open edge portion 6 of the can body 1. At this time, the edges of both parts 1 and 2 are formed in advance so that they are flush with each other.
The end edges of No. 2 are welded all around at the welding section 8.

In FIG. 4, reference numeral 9 indicates the welded portion.

Finally, the overlapping edge portions 6 and 7 of both 1 and 2 are bent outward using, for example, a known curling roll.

More specifically, the opening edge portion 6 of the can body 1 and the flange portion 7b of the lid plate 2 are integrally bent outward. At this time, it is preferably curled into a circle so that the welded portion 9 is difficult to see.

Second Embodiment FIGS. 5 and 6 show a second embodiment of the invention, in which a bottom lid plate 2 is attached to the lower open edge portion 6 of the can body 1.
In the case of fixing the same.

In this case, the lower opening edge portion 6 of the can body 1 is not bent at all in advance, and the outer peripheral edge portion 7 of the lid plate 2 is bent downward at a right angle to form the opening of the can body 1. After aligning the edge portion 6 with the outer peripheral edge portion 7 of the cover plate 2 and overlapping them, both 1 and 2 are welded together as described above, and then both 1 and 2 are welded together.
The edge portions 6 and 7 of 2 are simply bent outward into a U-shape.

Third Embodiment FIGS. 7 and 8 show a third embodiment of the invention, in which an upper lid plate 3 is attached to the upper open edge portion 6 of the can body 1.
This is the case when fixing. In this case, the opening edge portion 6 of the can body 1 is bent inward by a certain angle α, and the outer peripheral edge portion 7 of the lid plate 2 is bent upward ii' to follow the straight wall portion of the can body 1. It has a bent portion 7a bent at an F angle, and a flange portion 7b formed at the tip of the bent portion 7a by being bent inward by a certain angle α to conform to the inner surface of the inwardly folded opening edge portion 6 of the can body 1. However, in this case as well, can body 1 and lid plate 3
After overlapping the edge portions 6 and 7 of 9, the edges of both 1 and 3 are welded, and the first step is to bend the two can bodies 1 to the inside of the can body 1 using a curling die 10. The opening edge portion 6 of the can body 1 and the flange portion 7b of the lid plate 3 may be bent in advance by a certain angle α to the outside, and finally bent to the outside of the can body 1.

Others 1 For example, in the example shown in FIG. 3, the opening edge portion 6 of the can body 1 is bent outward and the lid plate (
Alternatively, the outer peripheral edge portion 7 of 2 or 3) may be overlapped with the open edge portion 6 of the can body 1 without being bent, and then welded and then bent in the manner described above.

As explained above, according to the method of the present invention, the can body I and the lid plate (2 or 3) are firmly joined by welding, so that airtightness is maintained even when external force is applied during processing or after can manufacturing. Perfectly guaranteed. Since no sealing material is required, the structure is simple and mass production is possible at low cost. It has the following advantages.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view showing an example of a can to which the present invention is applied. FIG. 2 is a vertical sectional view of the main parts of the conventional example. Figures 3 and 4 show the first embodiment of the present invention, and Figure 3 shows the main parts with the outer peripheral edge of the lid plate superimposed on the open edge of the can body. FIG. 4 is a longitudinal sectional view of the main parts in a state where the lid plate is fixed to the can body. 5 and 6 show a second embodiment of the present invention, and FIG. 5 is a vertical cross-section of the main parts in a state where the outer peripheral edge of the lid plate is overlapped with the opening edge of the can body. The plan view and FIG. 6 are longitudinal sectional views of the main parts with the lid plate fixed to the can body. 7 and 8 show a third embodiment of the present invention, and FIG. 7 shows the tVl of the main part in a state where the outer peripheral edge of the lid plate is overlapped with the opening edge of the can body. The folded view, Figure 8, shows the lid plate fixed to the can body! It is a vertical cross-sectional view of the main part of the island. 1... Can body, 2, 3... Lid plate. 8...Welding machine 8 9...Welding part. Figure 1 Figure 2 Figure 2 Figure 5 Figure 6 Figure 3 Figure 4 Figure 7

Claims (1)

[Claims] (11. After overlapping the opening edge of the can body formed into a cylindrical shape, the circumferential edge of the lid plate is welded together over the entire circumference, and 8. A can manufacturing method characterized in that the can body is bent on the outside or inside of the can body.