JPS6382949A - Easy-open can cover having excellent easy-open characteristic - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a partial opening lid (hereinafter simply referred to as an easy-open can lid) that can perform operations from opening to tearing the opening piece with extremely small force.

[Conventional technology]

The easy-open can lid allows the can lid to be opened using the pulling force of the fingertips without the need for tools such as a can opener. Taking advantage of this advantage, it is now used in a wide range of applications such as food cans, carbonated beverage cans, and beer cans.

In order to improve the openability of this easy-open can lid, various studies regarding can lids have been conducted. For example, an easy-open can with a main score engraved on the can lid and an auxiliary score adjacent to the main score was developed in Japanese Patent Application Publication No. 5
This method is proposed in Japanese Patent No. 8-149251.

In this way, by providing an auxiliary score, a certain improvement in can opening performance can be seen.

[Problem that the invention seeks to solve]

However, the ease or difficulty a person feels when opening an easy-open can lid largely depends on the magnitude of the force applied at the beginning of opening. That is, the greater the force required to start opening, the poorer the opening performance becomes. Furthermore, when opening with a large force, there is a risk that the pull tab may be torn rapidly, which may result in shock and vibration being applied to the entire easy-open can, and the contents may spill out. Furthermore, if the force required to start opening is significantly different from the force required during the subsequent tearing process, the opening piece will be torn off with a tactile sensation, giving shock and vibration to the can body, and causing the contents to leak. It may even start to spill.

However, when using the above-mentioned auxiliary score, there is a limit to the improvement in can opening performance, and a relatively large force is still required to start opening, and the change in the force used to tear the pull tab is also large. .

Therefore, an object of the present invention is to open an easy-open can lid in a stable state by reducing the force required to start opening and also reducing the tearing force thereafter.

[Means for solving problems]

In order to achieve the purpose of the easy-open can lid of the present invention, a score is engraved so as to surround the opening piece provided with the pull tab through the fixing part, and the score is inserted into the fixing part in the tearing direction. It has a concentric part provided concentrically with the fixing part on the apex side of the opening piece, and an overhanging part extending perpendicularly to the tearing direction following the concentric part, and the overhanging position of the overhanging part is set as above. a4ii! The angle of the concentric portion with respect to the center of the fixed portion is 90 degrees or less, and furthermore, the bending rigidity in the tearing direction is weakened in at least the front half of the opening piece! a4ii! It is characterized in that the processed portion is provided so as to intersect with the tearing direction.

The machined part here may be any of a straight line, two curved lines, a V-shaped or inverted V-shaped score, a thin part, a wavy part, or a bead.

〔Example〕

Hereinafter, features of the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 shows the easy-open can lid of this embodiment. A main score 2 and an auxiliary score 3 are engraved on this easy-open can M1. This auxiliary score 3 is a stress absorbing part that is provided as necessary along the main score 2 line to prevent cracks from occurring in the main score 2 when engraving the main score 2, and its remaining thickness is larger than the residual thickness based on main score 2. In order to ensure this stress absorption effect, it is desirable that the distance b (see FIG. 2) between the auxiliary score 3 and the main score 2 be 21 or less.

The inside surrounded by the main score 2 becomes the opening piece 4.

After a protrusion is press-molded near the apex 4a, the tension knob piece 6 is fitted into the protrusion and the protrusion is swaged to form the fixed portion 5 to which the tension knob piece 6 is attached.

FIG. 2 shows the shape of main score 2. This main score 2 includes a portion 2a provided concentrically with the fixed portion 5 on the side of the apex 4a from the Y-Y axis with respect to the X-X axis parallel to the tearing direction 7, and
It consists of a portion 2b that juts out symmetrically along the direction perpendicular to the axis, and a portion 2c that forms the outline of the opening piece 4 following this jutted portion 2b. The protruding position of the protruding portion 2b is at an angle φ between the center of the fixed portion and the X-X axis in the figure.
is formed at an angle of 90 degrees or less.

Note that the reference number 8 is an auxiliary score formed above the concentric portion 2a. This auxiliary score 8 has the function of facilitating the deformation of the opening piece 4 and promoting concentration of stress on the concentric portion 2a when the tension knob piece 6 is pulled. Also, similarly to auxiliary score 3, vertex 4a
This is also effective in preventing cracks from forming in the neighboring concentric portion 2a when scoring is carved. Note that forming the auxiliary score 8 can be omitted depending on the case.

Further, at least the front half of the opening piece 4 is provided with a machined portion 9 symmetrically with respect to the XX axis. The machined portion 9 can be formed in a linear shape, a square shape, an inverted V shape, or an arc shape, as shown in plan views in FIGS. 3fa) to +dl, respectively.

Also, its cross-sectional shape is a score 9a, an fIII flesh part 9b, and a wavy part 9c, as shown in FIG. 4 (δ) to (dl), respectively.

9d. Furthermore, it may be formed as a bead protruding inwardly or outwardly.

The mutual gap between adjacent machined parts 9 is preferably 2 to 5 mm. When maintaining the mutual gap within this range, a part where the bending rigidity is reduced due to one machined part 9 becomes continuous with a part where the bending rigidity is reduced due to another adjacent machined part 9, The opening piece 4 is now able to bend uniformly along its longitudinal direction. When this mutual gap exceeds 51, the force for tearing the opening piece 4 along the tearing direction 7 fluctuates greatly, making it impossible to open the can with a stable force. Moreover, when the mutual gap is less than 2 m1, the stiffness of the opening piece 4 becomes weaker than necessary, and in some cases, the opening piece 4 may be partially torn off.

In addition, when providing a ■-shaped or inverted V-shaped machined part 9, it is preferable that the angle θ (see Fig. 2) made by the seven sides of the machined part 9 with the normal line of the X-X axis is 45 degrees or less. . This angle θ
When the angle exceeds 45 degrees, the effect of the machined portion 9 on the reduction in rigidity that facilitates bending of the opening piece 4 in the XX axis direction becomes small.

In such an easy-open can lid, when the can is opened by pulling the pull tab 6, the opening starts from the apex 4a of the opening piece 4 provided with the fixing portion 5 along the concentric circular portion 2a of the main score. Here, since the shape of the main score 2 is as described above,
Bending stiffness about the shaft is reduced. That is, the overhang part 2
By forming b within the interval 2 from the apex 4a to the fixed part center line Y-Y axis, the stress generated by pulling up the tension knob 6 can be applied to the area where the concentric portion 2a intersects the X-X axis. It becomes easy to concentrate in a portion, that is, in the vicinity of the vertex 4a.

As a result, opening initiation is performed with less force.

Next, the tip of the tear portion of the opening piece 4 transitions from the concentric portion 2a to the overhanging portion 2b. This overhanging portion 2b is
Since it is provided near the fixed portion 5, the force that causes the tension knob 6 to be transmitted is magnified by the principle of leverage. Therefore, tearing along the overhanging portion 2b is also performed without requiring any additional large force.

In order to keep the force required to tear this part small,
The closer the overhanging portion 2b is to the Y-Y axis, specifically, it is desirable that the overhanging position be at an angle φ of 45 degrees or more between the center of the fixed portion and the X-X axis, as shown in FIG. That is, when there is an overhanging portion 2b at this interval l, when the tear point moves laterally along the overhanging portion 2b, the rigidity of the opening piece 4 is maintained by the relatively thick fixed portion 5, so that the lateral movement Directional movement is performed smoothly. In addition,
The angle of this overhanging portion 2b with respect to the tearing direction 7 is determined in order to exhibit the effect as described above, and does not refer only to a right angle in a geometric sense. Equivalent results are obtained when the angle is in the range of 90±12.5 degrees. Therefore, in this specification, this range is referred to as a right angle.

The tearing point moves from this overhanging portion 2b to the contour generating portion 2c. In this region, the opening piece 4 is easily bent by the machined part 9, so the tearing force is not dispersed elsewhere (it is concentrated on the main score as stress with high efficiency. Therefore, the tearing force in this region is Also, since the width of the opening piece 4 is expanded by the overhanging portion 2b, the area of the opening formed after tearing the opening piece 4 is also large.

In this way, the main score 2 is the concentric part 2a.

When the can is formed using the overhanging portion 2b and the contour generating portion 2C, the can can be opened smoothly. Since the bending rigidity of the opening piece 4 is reduced by the machining part 9, the tearing force during the tearing process is also small. In this way, the entire process of tearing the opening piece 4 from the lid body on the non-opening side can be performed with a small amount of force with little variation.

FIG. 5 specifically explains this effect using a graph. The solid line in FIG. 5 shows the variation of the can opening force along the longitudinal direction of the opening piece 4 when the easy-open can lid of the present invention is opened. Moreover, the broken line is an example of a conventional easy-open can lid with a normal score engraved on it.

As is clear from the comparison between the solid line and the broken line, the easy-open can lid of the present invention was able to open the can with a small initial opening force and tearing force. This makes it easy to open the can, and there is no impact on the can body when opening the can.

This means that unexpected movements such as vibrations are not applied.

Therefore, the contents do not spill out, and the edges of the opening formed after tearing off the opening piece 4 have a flat shape.

Also, the distance a (
(see FIGS. 2 and 7), the initial can-opening force sharply decreases when the distance a=O1411 is reached as shown in FIG. From this point of view, it is desirable that the distance a be 0.4 mm, preferably 0.3 weight.

Note that the lower limit of the distance a is preferably 0.1 mm in consideration of ease of processing using a mold.

The reason why the initial can opening force rapidly decreases after the interval a = 0.4 am is that the influence of the highly rigid fixed part 5 is transmitted to the concentric part 2a, and the stress concentration becomes more localized. considered to be a thing. Therefore, this concentric circular part 2
When the proximity of a and the fixed portion 5 is combined with the shape of the main score 2 described above, it becomes possible to open the opening piece 4 with less initial can opening force.

〔Effect of the invention〕

As explained above, in the easy-open can lid of the present invention, by improving the shape of the main score and reducing the bending rigidity of the opening piece, it is possible to start opening the can with a smaller force. In addition, the process from the start of opening to the separation of the opening pieces can proceed smoothly.

Furthermore, since the overhanging portion is provided in the middle of the main score, the area of the opening formed after tearing off the opening piece becomes large, making it easier to take out the contents after opening the can. Furthermore, since the tearing force is less variable, the opening formed in the easy-open can lid after removing the opening piece will have smooth edges. In this way, according to the present invention, an easy-to-open can lid with excellent can opening properties can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an easy-open can lid according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a score and a machined part provided on the lid, and FIGS. 3 and 4 are Several examples of machined parts are shown, and FIG. 5 is a graph specifically showing the effects of the present invention. FIG. 6 is a graph showing the relationship between the initial can opening force and the distance a, and FIG. 7 is a diagram illustrating the distance a.

Claims (1)

[Scope of Claims] 1. A score is carved so as to surround the opening piece provided with the tension knob through the fixed part, and the score is attached to the fixed part on the apex side of the opening piece from the fixed part in the tearing direction. It has a concentric circular part provided concentrically with and an overhanging part extending perpendicularly to the tearing direction following the concentric circular part, and the overhanging position of the overhanging part is set at an angle with respect to the center of the fixed part of the concentric circular part. is 90 degrees or less,
The easy-open can lid with excellent can opening characteristics is further characterized in that a machined part for weakening bending rigidity in the tearing direction is provided on at least the front half of the opening piece so as to cross the tearing direction. 2. The machined part according to claim 1 is linear,
An easy-open can lid with excellent can-opening characteristics characterized by a curved, V-shaped or inverted V-shaped score, thin wall portion, wavy portion or bead. 3. A can with excellent opening characteristics as set forth in claim 1 or 2, characterized in that the distance a between the apex of the opening piece and the outer periphery of the fixed portion of the tension knob is 0.4 mm or less. Easy open can lid.