JPH0565831U - Can lid - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the internal pressure of the can rises abnormally,
(EN) Provided is a can lid in which the score portion does not protrude from the can lid body. [Structure] The cut line 2 in the portion close to the counter sink formed in the can lid main body is provided with a step portion 20 formed to be shallower than the cut depth in the other portions.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a can lid opened by a Steion type tab.

[0002]

[Prior Art]

 In recent years, in order to prevent various problems caused by discarding the tab after opening the can, the tab and the can lid are partially connected to each other in the can opening portion of the can lid such as a beverage can. Stay-on tabs are being adopted.

FIG. 8 shows an example of an aluminum alloy can lid (for a 350 ml can having an outer diameter of about 64 mm) in which such a steion tab is used. In this example, the can lid has a substantially disc shape. A substantially U-shaped cut line 2 is formed on the surface of the formed can lid body 1 to define a score portion 3, and a stain tab (hereinafter abbreviated as a tab) is formed at one end of the score portion 3. 4) are joined via rivets 5.

Here, the tab 4 has a push-down portion 6 formed on one end side thereof so as to overlap the score portion 3, while a pull-up portion 7 for hanging the operator's fingertip on the other end side. The finger hole portion 8 is formed between the pulling portion 7 and the rivet 5 to improve the operability when opening the can. The pulling portion (the other end) 7 is pulled upward. Thus, the pressing portion (one end) 6 is brought into contact with the upper surface of the score portion 3 to press the score portion 3, whereby the score line 2 is torn and the score portion 3 is moved downward (inner surface side). The can lid 1 can be opened by folding.

Further, the can lid main body 1 is formed with a counter sink 1a (FIG. 9) which is bent downward so as to be convex along the outer periphery thereof, and the can lid K ( It is possible to improve the adhesion between the can lid and the can body K when being fixed by winding on the chain double-dashed line in FIG. 9. In addition, reference numeral 10 in FIGS. 8 and 9 is a sub-score that is formed by cutting shallower than the score line 2 and improves the easiness of breaking of the score line 2.

As means for forming the cut line 2, the can lid main body 1 is sandwiched between an upper die having a score blade 9 as shown in FIG. 10 and a lower die formed in a substantially flat plate shape. Then, the score line 9 is formed on the upper surface of the can lid main body 1 by the score blade 9.

By the way, in the conventional can lid, especially when a carbonated beverage, beer, or the like is filled as the contents, the internal pressure p (FIG. 9) easily rises due to vibration, shock, heating, etc. When the strength exceeds the internal pressure of the can lid, a part near the countersink 1a is plastically deformed, causing a so-called horning phenomenon in which the corners momentarily project upward. Here, when the vicinity of the counter sink 1a near the cut line 2 is cut out, the cut line 2 is broken from the portion close to the counter sink 1a (the vicinity of the bottom of the U-shaped cut line in the illustrated example). However, due to the blowing of gas or liquid inside the can, other parts of the score line 2 are instantly broken, and the connecting part (the score line 2 is formed between the score part 3 and the can lid body 1). It has been known from the past that a phenomenon (so-called missile phenomenon) in which the score part 3 flies for several meters due to breakage of the non-existing part) is called.

[0008]

[Problems to be solved by the device]

 The present invention has been made in view of the above circumstances, and an object thereof is to provide a can lid in which the score portion does not separate from the can lid main body even when the internal pressure of the can rises abnormally. ..

[0009]

[Means for Solving the Problems]

 The can lid of the present invention is configured such that the cut line near the countersink is provided with a step portion formed to be shallower than the cut depth in other portions.

[0010]

[Action]

 The stepped portion can receive the stress applied to the score line near the counter sink, prevent the score line from breaking due to the increase in the internal pressure of the can, and prevent the so-called missile phenomenon.

[0011]

【Example】

 A structure of a can lid according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The same components as those of the conventional can lid described above are designated by the same reference numerals, and detailed description thereof will be omitted.

In the can lid of this example, a portion of the cut line 2 close to the countersink 1 a (that is, near the bottom of the U-shaped cut line 2) is formed with a convex upward, thereby This is different from the conventional can lid in that a step portion 20 formed to be shallower than the cut depth in the portion is provided. The length of the step portion 20 along the direction of the score line 2 is 9 to 10 mm in this example. 2, reference numeral 2a indicates the vicinity of the opening start end of the cut line 2, reference numeral 2b indicates the opening end of the cut line 2, and reference sign S indicates the position where the rivet 5 should be attached to the can lid body 1 (hereinafter referred to as " It is called "rivet center").

Further, in the can lid of this example, the plate thickness of the can lid body 1 is 0.3 mm, the plate thickness of the cut line 2 portion is about 0.115 mm, and the maximum plate thickness of the step portion 20 is 0.195 mm. It is said that.

The position where the step portion 20 is formed in the can lid of this example will be described below with reference to FIG. Reference numeral L1 in the figure is a straight line that passes through the rivet center S and the center of the score part 3 and divides the score part 3 into two substantially equal parts. Further, in the can lid of this example, the step portion 20 is formed between the sections W (about 9 mm) centered on the straight line L1.

Next, the structure of the die for forming the cut line 2 of the can lid according to this example will be described with reference to FIGS. 3 and 4. The mold used in this example is provided with a score blade 19 having a recess 19a having a depth H1 (0.080 mm in this example) formed at a position corresponding to the step 20. Step portions 19b and 19c are formed in the concave portion 19a, and side surfaces of these are formed by inclined surfaces inclined at inclination angles θ1 to θ4. Here, the depth H2 of the step portion 19b is 0.005 mm in this example. Further, the inclination angles θ1 to θ4 are preferably in the range of 10 ° to 60 °. As in the conventional case, this mold is moved in the direction A in FIG. 3 and pressed against the surface of the can lid main body 1 to form the score line 2.

According to the can lid of this example, since the step 20 is formed in the portion of the score line 2 close to the counter sink 1a, vibration or impact is applied to the product can, and the internal pressure of the can increases. Even when plastic deformation occurs in the vicinity of the counter sink 1a, the stepped portion 20 can be subjected to stress, and therefore the so-called missile caused by the breakage of the score line 2 in the portion close to the counter sink 1a. There is an advantage that the phenomenon can be prevented.

Here, when the cutting depth of the cutting line 2 is formed to be uniform and shallow, it is possible to certainly improve the breaking strength and prevent the missile phenomenon, but the operation of the tab 4 is performed. However, in the can lid of this example, the stepped portion 20 is partially or locally formed in the portion close to the counter sink 1a. However, there is an advantage that the ease of opening the can can be stopped as much as possible, and a sufficient missile phenomenon prevention effect can be added.

In the can lid of the above-described embodiment, the step portion 20 formed on the cut line 2 has a flat shape as shown in FIG. 1, but the shape of the step portion 20 is as shown in FIG. It may have a slightly raised shape as shown in FIG. 5, or may be composed of two step portions 21 and 22 as shown in FIG. 6, and has a simple trapezoidal shape as shown in FIG. I don't mind.

[0019]

[Effect of the device]

 In the can lid of the present invention, since the cut line near the counter sink has a step portion formed to be shallower than the cut depth in other portions, the cut line near the counter sink is provided. It is possible to prevent the so-called missile phenomenon (protrusion of the score part) due to the breakage of the.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a can lid according to an embodiment of the present invention cut along a score line.

FIG. 2 is a plan view of an essential part showing a cut line portion of a can lid according to an embodiment of the present invention.

FIG. 3 is an enlarged sectional view of an essential part of a score blade portion of a mold used in an embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts taken along the line BB in FIG.

FIG. 5 is a view showing a modified example of the embodiment of the present invention, and is an enlarged sectional view of an essential part in a portion corresponding to FIG.

FIG. 6 is a view showing a modified example of the embodiment of the present invention, and is an enlarged sectional view of an essential part of a portion corresponding to FIG.

FIG. 7 is a view showing a modified example of the embodiment of the present invention, and is an enlarged sectional view of an essential part of a portion corresponding to FIG.

FIG. 8 is a plan view of a conventional can lid.

9 is an enlarged cross-sectional view of a main part taken along the line CC of FIG.

FIG. 10 is an enlarged perspective view of a main part showing a score blade portion of a mold used to form a score line in a conventional can lid.

[Explanation of symbols]

 1 Can lid main body 2 Cut line 3 Score part 4 Steion type tab 20 Step part

Claims (1)

[Scope of utility model registration request] 1. A substantially U-shaped cut line is provided to define a score portion, and a counter sink formed by being bent so as to be convex downward along an outer circumference. A disk-shaped can lid body and attached to this can lid body,
One end is overlapped above the score part, and the other end is pulled up to press the score part downward while bringing one end of the tab into contact with the top surface of the score part, thereby cutting the score line. A can lid provided with a steion-type tab that is cut from the opening start end toward the end and presses the score portion toward the inner surface side of the can lid main body to open, and in the score line, close to the counter sink. A can lid characterized in that a step portion formed to be shallower than the cut depth in the other portion is provided in the portion that is formed.