JPH0511136Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a can body in which an outer cylinder and an inner cylinder are integrally formed. Regarding the can body. BACKGROUND ART Conventionally, coffee, sake, and the like are often sold after being heated to an appropriate temperature in a vending machine to make them suitable for drinking. However, in outdoor activities such as mountain climbing or camping, it is impossible to instantly heat coffee cans, sake cups, etc. when eating or drinking.
Therefore, as a container that eliminates these drawbacks,
A can with a heating barrel has been developed that can instantly heat the contents inside the container using the heat of reaction from a chemical reaction.
In this can with a heating tube, an inner tube that houses a heat generating material therein is usually secured to the lower edge of an outer tube that houses contents such as alcoholic beverages and coffee. As such a can with a heating cylinder, there is one shown in FIG. In FIG. 3, 50 is the outer cylinder of the can with heating cylinder. The outer cylinder 50 is made by welding metal plates such as steel into a cylindrical shape, or by forming a composite material in which paper, aluminum foil, synthetic resin film, etc. are laminated into a cylindrical shape. Further, 51 is an inner cylinder, and this inner cylinder 51 is formed into a cup shape by drawing a metal plate, and the edge 51a of this inner cylinder 51 is wrapped around the edge 50a of the outer cylinder 50. . Problems to be Solved by the Invention However, in such a conventional can body, there is a risk that the contents may leak to the outside from the seamed portion of the outer cylinder 50 and the inner cylinder 51, and the outer cylinder 50 may and inner cylinder 51
It has the disadvantage that it takes time and effort to manufacture because it is made in separate processes and then combined and seamed separately. Furthermore, in the case of a can body in which the inner cylinder is integrally formed inside the outer cylinder by drawing and ironing the outer cylinder and then re-drawing the outer cylinder, the wall thickness of the outer cylinder, inner cylinder and bottom part are all made to be the same thickness. be done. Therefore, if the thickness of the bottom part is made thicker so as to withstand axial loads above a certain level, the wall thickness of the body wall of the outer cylinder also becomes thicker, which has the disadvantage of wasting can material. On the other hand, if the wall thickness is made thinner in order to save can material, the bottom wall thickness also becomes thinner, which causes the problem that the bottom part buckles due to the axial load applied to the can body when the lid is tightened. There is. This idea was created by focusing on these conventional problems, and aimed to create an economical can body that can withstand axial loads above a certain level and is compatible with the trend toward thinner can materials. The purpose of the present invention is to provide a can body that requires fewer manufacturing steps and is free from the risk of contents leaking. Means for Solving the Problem In order to achieve this object, this invention consists of (a) an outer cylinder consisting of a body side wall and a bottom side wall 3 that gradually increases in thickness from the lower end of the body side wall and continues downward; 2, (b) an annular bottom 6 that continues inward from the lower end of the bottom side wall 3, and (c) an inner cylinder 5 consisting of a side wall rising from the inner edge of the bottom 6 and a flat top are concentrically integrated. (d) The thickness of the body wall extending from the upper side of the bottom side wall 3 of the cylindrical body to the opening 4 is thinner than the thickness of the inner cylinder 5 and the bottom 6. Function The function of this device having the above structure will be explained. forming an inner cylinder 5 inside the outer cylinder 2;
In addition, the wall thickness of the bottom part 6 is made equal to that of the inner cylinder 5 and sufficiently thicker than that of the outer cylinder 2, so that the axial force applied to the bottom of the can body when tightening the lid or filling the contents is reduced. Capable of withstanding loads. Embodiment Next, this invention will be explained based on the drawings. FIG. 1 shows a sectional view of a can body according to this invention, in which an inner cylinder 5 is integrally formed inside an outer cylinder 2 by reverse redrawing. The feature of this invention, which is different from the conventional can body in which the outer cylinder 2 and the inner cylinder 5 are integrally molded, is that the inner cylinder 5 and the bottom part 6 are thick (a = 0.35 mm to 0.45 mm), and the outer cylinder 2 is thick. The thickness gradually changes at the bottom side wall 3, and the thickness of the body wall from the upper part to the opening 4 is thin (b = 0.24 mm
~0.15mm) point. Next, a method for manufacturing a can body according to this invention will be explained. First, a plate material such as Al or steel is punched into a disc shape, and this disc is drawn into a cup shape, and then subjected to drawing and ironing processing to create a can body with a bottom.
form. That is, the vicinity of the bottom (the range on the bottom side from the midsection 10) 7 is only subjected to drawing processing using a small diameter portion at the tip of a punch (not shown) having a step and a die ring. Further, the region from the midsection 10 of the can body 1 to the opening is drawn and ironed using a large diameter portion of a punch having a step and a plurality of die rings. That is, the wall thickness near the bottom 7 is approximately the same as the thickness of the cup before drawing, and the wall thickness of the can body 1 from the midsection 10 to the opening is thinner than the wall thickness near the bottom 7. Ru. The can body formed in this way,
As shown in FIG. 2, cover the die 8 with the bottom part 7 facing upward, press the bottom outer periphery with a wrinkle presser 9,
It is pushed into the inside of the die 8 with the punch 11 and reverse re-drawing is performed. As shown in FIG. 1, the region from the midsection 10 of the can body 1 to the opening forms a thin outer cylinder 2, and the region 7 near the bottom forms a thick inner cylinder 5 and a bottom 6. The midsection 10 forms a bottom sidewall 3 of varying thickness. Next, Table 1 shows the relationship between the wall thickness of the bottom portion 6 and the buckling strength against axial loads.

[Table] From Table 1, even if the outer cylinder 2 is made thinner in order to save can material, the bottom part 6 must be made thicker to withstand the load applied in the axial direction when the lid is tightened. It's obvious what you have to do. (Material
When tightening the lid of A3004 can with a can diameter of 66 mm and an outer cylinder wall thickness of 0.21 mm, the required buckling strength at the bottom must be at least 150 kg. ) As is clear from Table 1, the bottom part 6 of the can body according to this invention sufficiently satisfies the buckling strength required when tightening the lid,
Furthermore, this is a new can body in which the body wall of the outer cylinder 2 is made thinner to save can material. Furthermore, since the inner surface coating of the can body according to this invention is applied before the reverse re-drawing process, uniform coating can be achieved as a whole, resulting in a beautiful finish. Effects As explained above, this invention provides the following effects. (1) The thickness of the outer cylinder is made thinner by drawing and ironing, which saves can material and is very economical.The bottom part of the can is thicker, making it easier to tighten the lid. The bottom part will not buckle due to the axial load applied to the can body. (2) Since the outer cylinder and inner cylinder are made by integral molding, there is no leakage of contents. (3) The outer cylinder and the inner cylinder are manufactured separately, and there is no process of seaming each, making it possible to reduce the number of manufacturing processes. (4) Since a region where the thickness gradually changes is provided on the bottom side wall of the outer cylinder, stress concentration can be avoided and this contributes to preventing buckling.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the can body according to this invention. A cross-sectional view of the can body according to the invention being molded,
FIG. 3 is a sectional view of a conventional can with a heating tube. 1...Can body, 2...Outer cylinder, 3...Bottom side wall, 4
...opening, 5...inner cylinder, 7...near the bottom.

Claims (1)

[Claims for Utility Model Registration] (a) Inside an outer cylinder consisting of a body side wall and a bottom side wall that gradually increases in thickness from the lower end of the body side wall and continues downward, (b) Said bottom side wall. (c) an inner cylinder consisting of a cylindrical side wall rising from the inner edge of the bottom and a flat top are integrally formed in a concentric manner; (d) of the outer cylinder; A can body characterized in that the thickness of the body wall extending from the upper side of the bottom side wall to the opening is thinner than the thickness of the inner cylinder and the bottom.