JPH0444944A - Neck-in can body - Google Patents

Abstract

PURPOSE:To simplify examination, etc., of various factors for securing strength by respectively regulating a gradient angle of each gradient part of a can body having a necked-in part and a sum of gradient angles on one end and the other end of the gradient part connected to the necked-in part of a can body. CONSTITUTION:A necked-in can body 1 is a three-piece can comprising an approximately cylindrical can body 2 and can lids 3 seamed on both ends of the can body 2 for example, wherein necked-in parts 5 having one step of a gradient part 4 from a flat body side wall 2a to the can lid 3 are formed respectively on both ends of the body 2. theta1 refers to an acute gradient angle to the can body side 2a of the gradient part 4 connected from the can body side wall 2a to the necked-in part 5 on a side of the upper end, and theta2 refers to an acute gradient angle to the can body side 2a of the gradient part 4 connected from the can body side wall 2a to the necked-part 5 on a side of the lower end. Both gradient angles theta1 and theta2 are specified to be 45 deg. or smaller and also theta1+theta2 is specified to be 36 deg. or larger. A decrease in theta1, theta2 causes buckling strength to increase, while an increase in theta1+theta2 causes paneling strength to increase.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a so-called three-piece can consisting of a substantially cylindrical can body and a can lid that is wrapped around both ends of the can body. This invention relates to a can body in which twin portions are formed at both ends of the can body.

(Prior Art) It is known that in three-piece cans used for beverage cans, neck-in portions are formed at both ends of the can body by drawing, etc., in order to save material for the can lid. The neck-in portion is usually provided with one or more inclined steps.

On the other hand, in this type of 3-piece can, the strength of the can body against external pressure when filled with contents (so-called bubbling strength) and the strength against external pressure along the axis of the can (
It is necessary to ensure that the so-called buckling strength) is above a certain level. For example, for ordinary beverage cans, etc., the spring ring strength is 1.5 kg/C111 or more, and the buckling strength is 2.
00 kg or more is desirable.

In this case, factors that affect the spring ring strength and buckling strength include various factors such as the size and shape of the can body, the wall thickness of the can body, and the material of the can body. For can bodies, such as beverage cans, whose shape, capacity, material, etc. are conventionally determined to some extent, many of these factors are restricted within very limited ranges. Conventionally, when designing a can body,
By repeating trial and error within the limits of the various factors mentioned above, a can body that can secure the necessary strength was designed.

However, when designing the can body, trial and error was repeated regarding various factors, which required a great deal of time and effort.

(Problems to be Solved) The present invention eliminates such inconveniences and minimizes the need to consider factors that affect the strength when designing a can body that has neck-in portions at both ends of the can body. It is an object of the present invention to provide a can body that can secure the required strength.

(Means for Solving the Problems) The inventors of the present invention have conducted various studies on the factors that affect the strength of can bodies, and as a result, the inventors of the present invention have found that the shape, capacity, etc. of cans are fixed to a certain extent like ordinary beverage cans, etc. For 3-piece cans, among these factors, the inclination angle of the acute angle side of each inclined step of the neck-in portion at both ends of the can body with respect to the side wall of the can body is particularly important for the springing strength and buckling strength of the can body. There is a close relationship with this, and as the inclination angle increases, the springing strength improves but the buckling strength decreases, and conversely, as the inclination angle decreases, the springing strength decreases but the buckling strength improves. However, it has been found that by appropriately setting the inclination angle of each inclination step, it is possible to ensure the required strength of the can body.

As a result of further consideration of this angle of inclination,
In order to secure the necessary buckling strength, it is essential that the angle of inclination of each inclined step is 45 degrees or less; if even one of them is greater than 45 degrees, the buckling strength will decrease and the necessary It was found that it was not possible to ensure sufficient buckling strength.

In addition, regarding the spring ring strength of the can body, in particular, the sloping step section that extends from the flat side wall of the can body to the neck-in section at one end of the can body, and the sloping step section that extends from the neck-in section at the other end side. Both of these together greatly affect the spring ring strength of the can body, and in order to ensure the necessary spring ring strength, it is essential that the sum of the inclination angles of both of the slope steps is 36 degrees or more, It has been found that if the sum of the inclination angles becomes smaller than 36 degrees, the spring ring strength decreases and the necessary spring ring strength cannot be secured.

Therefore, in order to achieve the above object, the neck-in can body of the present invention consists of a generally cylindrical can body and a can lid that is wrapped around both ends of the can body. In a can body in which a neck-in portion is formed, each of which has one or more inclined step portions, the angle of inclination of the acute angle side of each inclined step portion with respect to the flat can body side wall is 45 degrees or less, and an inclination angle on the acute angle side of the sloping stepped portion that extends from the side wall of the can body to the neck-in portion at the other end of the can body; It is characterized in that the sum of the inclination angles on the acute angle side of the inclined stepped portions is 36 degrees or more.

(Function) According to this means, the springing strength and buckling strength of the can body can be increased by setting each inclined stepped portion of the neck-in portion of the can body so that its inclination angle satisfies the above-mentioned conditions. For practical purposes, it becomes possible to secure a level higher than that required.

(Example) FIG. 1(a) shows an embodiment of the neck-in can body of the present invention.

(b) and Table 1. Figure 1(a),
(b) is a side view of the manufactured neck-in can body.

Neck-in can body 1 (hereinafter simply can body 1) shown in Fig. 1(a)
) is a three-piece can consisting of a substantially cylindrical can body 2 and can lids 3, 3 that are secured to both ends of the can body 2,
Neck-in portions 5 are formed at both ends of the can body 2, each having a one-step inclined step portion 4 extending from the flat can body side wall 2a to the can I3.

On the other hand, like the can body 1, the neck-in can body 6 shown in FIG.
It is a 3-piece can consisting of a can lid 8°8 which is secured to both ends, and a flat can body side wall 7 is attached to the upper end of the can body 7.
Three sloping steps 9a, 9b, 9c from a to the can lid 8
A neck-in portion 10 is formed at the lower end of the can body 7, and a neck-in portion 12 is formed at the lower end of the can body 7. The neck-in portion 12 has a one-step inclined stepped portion 11 extending from the flat can body side wall 7a to the can lid 8.

In addition, in FIGS. 1(a) and (b), H is the can body 1,
6 (hereinafter referred to as the can body length), L is the length of the flat can body side walls 2a and 7a (hereinafter referred to as the can body length), and D is the can body 1.
．． 6 is the inner diameter (hereinafter referred to as can diameter), d is the wall thickness of the can bodies 2 and 7, and N1 is the neck-in portion 5 on the upper end side of the can bodies 1 and 6. l
The length of O (hereinafter referred to as neck-in length), N2 is the can body 1
, 6 on the lower end side of the neck-in portion 5.12 length (hereinafter,
(referred to as neck-in length), θ1 is the acute angle side with respect to the can body side walls 2a, 7a of the inclined step portions 4, 9a that connect from the can body side walls 2a, 7a to the neck-in portions 5, 10 on the upper end side of the can body 1°6. The inclination angle θ2 is from the can body side walls 2a, 7a to the can body 1,
The side walls of the can body of the inclined stepped portions 4, 11 that are connected to the neck-in portion 5.12 on the lower end side of the can body';! a, is the inclination angle on the acute side with respect to 7a, and in FIG. 2(b), θ3.
θ4 is the slope step portion 9 of the neck-in portion 10 of the can body 6, respectively.
b, 9c are the acute angles of inclination with respect to the can body side wall 7a.

The inventors of the present invention determined that the can body length H1, the can diameter D, the wall thickness d, the neck-in lengths Nl and N2, and the inclination angle θ1.
A plurality of can bodies 1 and 6 having different angles of ~θ4 were manufactured, and for each of them, the can body length H, etc., and the spring ring strength and seat M strength were measured. Table 1 shows the measurement results.

In Table 1, can body No. Can bodies No. 1 to 9 are examples of the present invention, and can bodies No. 10 to 12 are comparative examples.

Among the examples, can body No. 0. 1 to 6 are the first
The can body 1 having the shape shown in FIG. 1(a) and the cans Nos. 007 to 9 are the can bodies 6 having the shape shown in FIG. 1(b),
Among the comparative examples, those with can bodies No. 0.10.11 are shown in Figure 1 (
a) The can body 1 having the shape shown in FIG.

In this case, the manufactured can bodies 1 and 6 are ordinary beverage cans with a content capacity of 200 Ml, 250 Ml, 350 Ml, and 350 Ml, as shown in the same table, and the can body length H1 can diameter and wall thickness d. is a typical value used for this type of beverage can.

In addition, the spring ring strength of the manufactured can body 1.6 was determined by sealing only air at atmospheric pressure inside a pressure vessel, and then gradually increasing the pressure inside the pressure vessel. The buckling strength is measured by reading the pressure when the shells 2 and 7 are deformed.On the other hand, the buckling strength is measured by moving the can lid along the axis of the can shell 2 and 7 with only air at atmospheric pressure sealed inside. 3.8
A load was applied to the can body 2.7, and the load was measured by reading the load when the can body 2.7 buckled.

Hereinafter, in the description, examples of can bodies Nos. 1 to 9 will be abbreviated as Examples 1 to 9, and comparative examples of can bodies Nos. 10 to 12 will be abbreviated as Comparative Examples 10 to 12.

As can be seen from Table 1, in Examples 1 to 9, each inclined step portion 4
．． The inclination angles θl to θ4 of 9a, 9b, 9c, and 11 are all 45 degrees or less, and the inclination angles θl, θ
2, the sum θl+θ2 is 36 degrees or more, and in these Examples 1 to 9, the spring ring strength and buckling strength are both the above-mentioned required strength 1.5 kg/
cij is over 200 kg, which indicates that the strength required for practical use is secured.

In this case, as can be seen by comparing Examples 4 and 5 or Examples 7 and 8, the buckling strength increases as each of the inclination angles θ1 to θ4 becomes smaller, and the buckling strength increases as the inclination angles θ1 to θ4 become smaller. As the sum θl±θ2 of θ2 increases, the springing strength increases.

On the other hand, in Comparative Examples 11.12, the sum θ of the inclination angles θl and θ2
Although 1+θ2 is more than 36 degrees, the inclination angle θ
At least one of 1 to θ4 is larger than 45 degrees, and in these comparative examples 11 and 12, the spring ring strength is the required strength of 1.5 kg/c1i! Despite the above, it can be seen that the buckling strength does not reach the required strength of 200 kg. In this case, for example, as can be seen by comparing Example 4 and Comparative Example 11, or Example 9 and Comparative Example I2, when any one of the inclination angles θ1 to θ4 exceeds approximately 45 degrees, the buckling strength decreases significantly. It turns out that it does.

Further, in Comparative Example 10, the inclination angle θ1. θ2 is 4 in both cases
Although the angle of inclination is 5 degrees or less, the sum θ1 + θ2 of the inclination angle θ1゜θ2 is smaller than 36 degrees.In Comparative Example 10, although the buckling strength is more than the required strength of 200 dazzles, the springing strength is The required strength is 1.5k
It can be seen that the value does not reach g/cm. In this case, the inclination angle θ1 of Comparative Example 10. Although the sum θ1 + θ2 of θ2 is 30 degrees, which is relatively close to 36 degrees, the buckling strength is significantly lower than Examples 1 to 9.

(Effects) As is clear from the above description, according to the neck-in can of the present invention, in a can body in which a neck portion having one or more inclined step portions is formed at both ends of the can body, , the inclination angle of the acute angle side of each inclined step with respect to the flat side wall of the can body is 45 degrees or less, and the acute angle of the inclined step continues from the side wall of the can body to the neck-in part on one end side of the can body. By making the sum of the side inclination angle and the inclination angle of the acute angle side of the inclined step part continuous from the side wall of the can body to the neck-in part on the other end side of the can body to be 36 degrees or more, In a three-piece can such as a can, the spring ring strength and buckling strength can be reliably ensured at a practically required level or higher. In this way, the required strength of the can body can be secured by appropriately setting the inclination angle of each sloping step part of the neck-in portion, so that the strength can be ensured when designing the can body. It is possible to simplify the examination of various factors for the design, and it is possible to significantly reduce the labor and time required for the design.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are side views of a can to which the neck-in can of the present invention is applied. 1.6... Neck-in can body 27... Can body 2a, 7a... Can body side wall 3.8... Can lid 4, 9 a, 9 b, 9 c, 11 - Inclined stepped portion 5 , 10.12...Neck-in portion θl~θ4...Inclination angle

Claims (1)

[Claims] 1. Consisting of a generally cylindrical can body and a can lid wrapped around both ends of the can body, each end of the can body has a neck-in portion having one or more sloping steps. In the can body, the angle of inclination of the acute angle side of each inclined step with respect to the flat side wall of the can body is 45 degrees or less, and
an acute angle side inclination angle of a slope step extending from the side wall of the can body to a neck-in portion at one end of the can body; and an inclined step extending from the side wall of the can body to a neck-in portion at the other end of the can body. A neck-in can body characterized in that the sum of the inclination angle of the acute angle side of the part is 36 degrees or more.