JPH0348034Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a can lid for a simple opening can that opens the can by pulling an opening tab provided on the can lid.

Prior Art The opening of so-called easy-open-end cans, in which the can is opened by pulling the opening tab provided on the can lid, involves tearing the opening along a score line stamped on the can lid panel. It is done by hand.

The shape of the conventional tear opening, that is, the score line, is formed by connecting a small circular part, which is the initial opening part, and a large circular part, which is the final part of the opening, with a straight line, as shown in FIG. . The opening of the can lid is made by pulling up the opening tab and breaking the small circular part by the pushing action of the opening tab, and by pulling the opening tab, breaking from the straight part to the large circular part. The score break is performed in the following order: the score tear, which separates the tear opening from the panel surface, and the cut-off, which separates the tear opening from the panel surface.The opening force required for the tear opening is the largest at the score break. Therefore, the difficulty of opening depends on the difficulty of score breaking.

The difficulty in opening the lid of the simple opening can varies considerably depending on the material of the lid material. For example, the score breaking force of a lid made of aluminum material is approximately
1.0 to 1.5 Kgf, whereas those made of tin or steel plate require a score breaking force of about 2.0 to 2.5 Kgf, which is particularly large compared to aluminum materials.

Therefore, cans with lids made of tin or steel plates (for example, for salt-containing contents such as tomato juice, lids made of these materials are exclusively used due to corrosion resistance issues).
The problem was that it required great score-breaking power and was difficult to open.

Conventionally, as a measure to improve the opening property, for example, the position of the score line on the long axis of the tension piece passing through the center of the rivet is set as the minimum separation point from the rivet center, and the position of the score line on the long axis line passing through the center of the rivet is set at the minimum distance from the rivet center. Draw a score line through the range defined by the first auxiliary line, which is assumed to be orthogonal, and the first auxiliary line, which is assumed to form an angle of 25 degrees with the first auxiliary line on the rivet side of the first auxiliary line. A pair of knob-shaped score lines extending from side to side and protruding outward to expand and form on both sides of the rivet have their maximum separation points from the center of the rivet in the range, etc. Therefore, a method has been proposed in which the score shape of the score break part is changed to concentrate stress and reduce the score break force (Tokuko Sho).
(Japanese Patent Publication No. 60-1214, Japanese Patent Publication No. 60-1215) Problems to be Solved by the Invention The previously proposed measures mentioned above have had a certain effect on reducing the initial opening force, but However, it is still not sufficient to reduce the opening force of a lid made of aluminum to the same level as that of an aluminum lid, and there is a need to improve the opening ability of these cans.

The present invention was devised in view of the above-mentioned circumstances, and is applicable to easy open ends made of tin or steel plates, which are relatively difficult to open. The object of the present invention is to provide a lid for a simple opening can that employs a line printing pressure position.

Means for Solving the Problems The can lid of the simple opening can of the present invention has a hollow rivet protruding from the tip of the tear opening surrounded by the score line coined on the lid panel surface. In the simple opening lid in which the opening tabs are caulked together, the score line in the score break portion is symmetrically arranged with the vertex located on the opening tab side on the long axis line of the tear opening passing through the center of the rivet. Formed at an acute angle in the range of 45 degrees to 75 degrees to the long axis to the minimum distance from the rivet center, and extending from the rivet center to a range defined by an imaginary line passing through the rivet center and orthogonal to the long axis. It is characterized in that it is formed laterally symmetrically in the shape of a bump following the minimum separation point so that the maximum separation point is located.

The angle of the top of the score line forming the initial opening is
As shown in Figure 3, the opening force is lowest at 60 degrees; if the angle is too large, the force will be dispersed, and if the angle is too small, the distance from the rivet will be long and a large opening force will be required. A range of 15 degrees is desirable as a range that can be opened with a low opening force, and is therefore limited to the above range.

Function The function of the present invention will be explained below with reference to the drawings of the embodiments.

When the central tip portion 8 of the opening tab 4 is lifted, the tip portion of the rivet 5 is lifted by a screwing action using the rear ends 9, 9' of the opening tab 4 as fulcrums, and a shearing force is applied to the panel surface. At this time, since the shape of the score line suddenly changes at the vertex A on the long axis, stress concentration occurs in this portion, promoting breakage in this portion. Therefore, it is possible to open the opening even with a relatively weak opening force. When a break occurs at point A, the break progresses all at once through the minimum distance point B to the bump-shaped portion due to the pushing action of the opening tab 4, resulting in a score break.

Example Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 shows an embodiment of the lid of a simple opening can according to the present invention, and FIG. 2 is an enlarged plan view of its characteristic parts.

In the figure, 1 is the lid panel surface and 2 is the tear opening surrounded by the score line in FIG.
Reference numeral 4 designates an opening tab which is caulked to a hollow rivet 5 formed protrudingly from the tip of the tear opening 2. 6 and 6' are beads, and 7 is a recess formed in a portion where the opening tab 4 is located. In the above structure, the other structure is the same as the conventional one except for the shape of the tip of the score line.

The score line of the score break part is a long axis line of the tear part 2 passing through the center O of the rivet 5 - the point A located on the opening tab side above is the apex, and the score line is symmetrical in a straight line at an acute angle of 60 degrees to the minimum separation point B. , and following the minimum separation point B so that the maximum separation point C is located in the range of 25° to 30° from the apex A with respect to the long axis passing through the apex A - an imaginary line perpendicular to the long axis line - It is symmetrically formed in the shape of a lump. Form the score line of the score break part as described above,
The other part of the score line is formed in an endless shape as in the conventional case, as shown in FIG.

When the score breaking power of the can lid having the score line of the above example and the can lid having the conventional score line were compared, the results shown in FIG. 4 were obtained. The figure shows the opening force measured for each score residual (residual thickness of the score line). In the graph shown in the figure, a is a conventional can lid in which the score line of the score break part is circular, b is a conventional can lid with bump-shaped score lines on both sides, and c is a conventional can lid in which the score line of the score break part is circular. This is the lid of the can. As is clear from this graph, the score breaking force of the present invention was reduced by about 0.5 Kgf compared to the one with the conventional score line, and the lid could be opened with an opening force close to that of an aluminum lid.

In the above embodiment, the score line is formed in a straight line from the apex A to the minimum separation point B, but the score line may be formed in an arc shape as long as it is bent at an acute angle at the apex.

Effects As described above, in the present invention, the shape of the score line of the score break part is formed so that the apex A on the long axis is an acute angle, stress concentration occurs in this part, promoting breakage, and relatively It can be opened with a weak score-breaking force, and the opening performance has been dramatically improved compared to the conventional method. Therefore, even with lids made of tin or steel plate, which were previously difficult to open,
It has remarkable effects such as being able to be opened easily with an opening force close to that of an aluminum lid.

Moreover, if it is used in an aluminum lid, the score residual can be increased, the strength will be increased, and it goes without saying that the opening property will be further improved.

[Brief explanation of the drawing]

Figure 1 is a plan view of a can lid according to an embodiment of the present invention;
The figure is an enlarged plan view of the main part, Figure 3 is a graph showing the relationship between score line tip angle and opening force, Figure 4 is a graph showing the relationship between score residual and opening force,
FIG. 5 is a plan view of a conventional score line defined tear opening. 1: Lid panel, 2: Tear opening, 3: Score line, 4: Opening tab, 5: Rivet, A: Score line apex, B: Minimum separation point, C: Maximum separation point.

Claims (1)

[Claims for Utility Model Registration] (1) A simple opening in which a hollow rivet is protruded from the tip of a tear opening surrounded by score lines coined on the lid panel surface, and an opening tab is caulked and connected to the hollow rivet. In the lid of the can, the score line in the score break part is symmetrical at 45 degrees to the long axis with the vertex located on the opening tab side on the long axis of the tear opening passing through the center of the rivet. The rivet is formed at an acute angle in the range of 75 degrees to the minimum distance from the rivet center, and the maximum distance from the rivet center is in a range defined by an imaginary line passing through the rivet center and perpendicular to the long axis. 1. A can lid for a simple opening can, characterized in that a can lid is formed laterally symmetrically in the shape of a bump following the minimum separation point so that the lid is located at the minimum separation point. (2) The simple opening can according to claim 1 of the utility model registration claim, wherein the position of the maximum separation point is within a range of 60 to 65 degrees from the apex to the long axis. lid.