JPH0323421B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an easy-to-open lid, and more particularly to an easy-to-open lid that is opened by tearing an annular score portion defining an opening panel portion using a tab.

Conventionally, there has been known an easy-opening lid 1 of the type shown in FIG. 1, which is a relatively small-diameter cap (for example, about 30 mm in diameter) that has a cap body 2 and a tab 3 for sealing a small-diameter bottle opening. ing. The cap body 2 is made of a thin metal plate such as an aluminum (alloy) plate, and includes a sunken top plate 4, a circumferential annular protrusion 5 surrounding the top plate 4, and a skirt portion hanging down from the outer edge 5a of the circumferential annular protrusion 5. It is equipped with 6.

The outer surface of the top plate 4 has an inner edge 5b of the peripheral annular protrusion 5.
An annular score portion 8 defining the opening panel portion 7 is formed along the opening panel portion 7 .

A rivet portion 9 for fixing the knob tab 3 is formed in the opening panel portion 7 in proximity to a first portion 8a of the score portion 8 which is the initial cut portion.

The knob tab 3 includes a ring-shaped knob part 3a and a nose part 3b for initially cutting the first portion 8a of the score part, and is fixed to the rivet part 9 via a joining panel 3c.

Since the top plate 4 has a small diameter, the portion 3a ₁ of the knob 3a facing the nose portion is close to the second portion 8b of the score portion 8 facing the first portion 8a. As shown in FIG. 3a, the score portion 8 is formed to have a trapezoidal cross section.

Score part 8 of the conventional easy-to-open lid 1 of this type
The remaining thickness t (FIG. 3a) was formed to be substantially equal along the entire circumference. In this case, the smaller the remaining thickness, the smaller the force required to open the opening, but if the remaining thickness is small (for example, 55 μm or less in the case of an original thickness of 0.27 mm), pinholes are likely to occur in the score portion 8 and the sealing performance is likely to be impaired. As shown in FIG. 3b, a defective deformed score portion 8' that causes a level difference between the outside and inside of the score portion 8 is likely to occur, and the score portion 8 is also likely to be cut during work such as fixing the knob tab 3. This causes a problem.

Furthermore, the opening is located at the knob 3 as shown in FIG.
Insert your finger into the knob part 3a of the knob tab 3.
After pulling up in the direction of arrow A and pushing down the nose part 3b to cut the first part 8a of the score part 8 and its vicinity, pull the knob part 3a in the direction of arrow B to cut the remaining part of the score part 8. This is done by tearing the second part 8b, and finally separating the second part 8b, but if the remaining thickness is uniformly thin, the tearing and separation will occur almost simultaneously and at that moment, As shown in FIG. 5, fingers are likely to be injured by hitting the sharp end surface of the opening panel section 7 in the broken score section 8 (the second section 8 of the score section
(b) and the portion _3a1 of the knob are close to each other.

On the other hand, if the residual thickness becomes large (for example, 80 μm or more in the case of an original thickness of 0.27 mm), opening becomes difficult, and in extreme cases, opening becomes impossible. Therefore, the range of selection of the remaining thickness is narrow, and if the remaining thickness goes out of the appropriate range due to work conditions etc., the above-mentioned troubles are likely to occur.

Utility Model Application Publication No. 57-43239 discloses that when the remaining thickness of the score part is large and the area around the knob tab is weaker than the score part, defects such as tearing from the base of the knob tab occur. In order to prevent this, an upper lid has been proposed in which the score portion near the first breakage portion near the tip (nose portion) of the knob tab is made thin over an appropriate length.

However, in the case of this top lid, the portion of the score portion away from the tip of the knob tab, which is not thin, is uniformly thick. In other words, the residual thickness is uniformly increased. If the remaining thickness of the score part is uniform,
Apply a particularly large tearing force near the position where the distance between the opposite ends of the tearing part of the score part reaches its maximum length (if the score part is annular, positions 11a and 11b in Fig. 6). After that, the force required for tearing will gradually decrease.

Therefore, in the case of the top cover, if the remaining thickness of the uniformly thick score portion is relatively large, it will be difficult to tear near the position where the gap reaches its maximum length, and this will cause strain on this portion. If a large force is applied to tear it, the downstream part has little tearing resistance, so it will be torn rapidly, which may cause injury to the hands and fingers.

On the other hand, when the remaining thickness of the uniformly thick score portion is relatively small, tearing is relatively easy near the position where the gap reaches its maximum length, but the tearing resistance at the end the smallest part (8b in Figure 6 if the score part is annular)
Then, the tearing and the above-mentioned separation occur rapidly at almost the same time, resulting in the problem of easy injury to hands and fingers.

The present invention provides a method for tearing an annular score portion that defines an opening panel portion using a grip tab, so that the initial stage of cutting the score portion and the opening by tearing are performed smoothly throughout, and there is no risk of injury to fingers during opening. An object of the present invention is to provide an easy-to-open lid of a type that can be opened by using a screwdriver.

The present invention provides an easy-to-open lid that is opened by tearing an annular score portion that defines an opening panel portion using a knob tab, and in which the opening panel portion is provided with a knob tab adjacent to a first portion of the annular score portion. The tab has a ring-shaped knob and a nose for initially cutting the first portion of the annular score, and the tab has a ring-shaped knob and a nose for initially cutting the first portion of the annular score. The portion facing the annular score portion is close to the second portion of the annular score portion opposite to the first portion of the annular score portion, and the annular score portion is adjacent to the first portion and the second portion thereof. , and the two intermediate parts including the part where the distance between the annular score parts in the direction perpendicular to the straight line connecting the first part and the second part is maximum between the two neighboring parts. The remaining thickness of the annular score portion is gradually thickened in the order of the first portion including the first portion, the intermediate portion, and the second portion including the second portion. Its neighboring part, including the second part, has a central angle (θ) of 30
The present invention provides an easy-to-open lid characterized by an arcuate portion of ~100 degrees.

Examples will be described below.

The easy-to-open lid 1 of the present invention is similar to the conventional easy-to-open lid 1 except that the remaining thickness of the score portion 8 varies in the circumferential direction. That is, the residual thickness of the first portion 8a and its neighboring portion 10 (center angle α) shown in FIG. (preferably about 60 μm), the second portion 8
The residual thickness of the neighboring portion 12 (central angle θ) including b is uniformly the largest (in the above case, preferably about
90 μm), intermediate portion 11 between portion 10 and portion 12
The residual thickness of (center angle β) is uniform between portion 10 and portion 1.
2 (in the above case preferably about 70 μm). The preferred ranges of central angles α, β and θ are 70 to 130 degrees, respectively.
65 to 130 degrees and 30 to 100 degrees (however, α+
2β+θ=360 degrees).

Therefore, the neighboring portion 1 including the first portion 8a
0, the initial cutting by the nose portion 3b is easily performed. Furthermore, there is no risk of pinholes occurring in the score section 8 or formation of defective deformed score sections 8', and there is no risk of the score section 8 being cut during work.

Further, after the initial cutting is performed and the tearing is started, the tip of the tearing part reaches the position where the distance between the opposing parts of the score part 8 reaches the maximum length (that is, the first part 8a is perpendicular to the opening direction). and the position 11a corresponding to the maximum interval perpendicular to the straight line connecting the second portion 8b, that is, α=180 degrees,
11b), if the remaining thickness is uniform in the circumferential direction, the force required for tearing will gradually increase;
Since the remaining thickness of the intermediate portion 11 including b is relatively thin,
Tearing occurs smoothly with relatively little force.

On the other hand, when the tip of the tearing part passes the positions 11a and 11b, if the remaining thickness is uniform in the circumferential direction, the force required for tearing gradually decreases; Since the remaining thickness of the neighboring portion 12 (the arcuate portion with the central angle θ of 30 to 100 degrees with the second portion 8b at the center) is relatively thick,
The tearing force does not become particularly small, and a relatively large resistance is generated in the separation of the second portion 8b, so that the tearing and separation proceed smoothly, and at the end of the opening, the opening panel portion 7 suddenly closes to the top plate 4. There is no risk of injury to hands or fingers due to being separated from the device.

The reason why the central angle θ of the neighboring portion 12 including the second portion 8b is set to 30 to 100 degrees is as follows.

If the central angle θ is smaller than 30 degrees, the arc length of the neighboring portion 12 including the second portion 8b with a relatively large residual thickness will become too short, so the intermediate portion will be separated until the second portion is finally torn. If the force of tearing No. 11 cannot be suppressed and the opening panel part tends to rapidly separate from the top plate, on the other hand, if the central angle θ is larger than 100 degrees, the neighboring parts including the second part 8b where the remaining thickness is relatively large. Since the arc length of 12 becomes too large, a relatively large force is required to tear the neighboring portion 12 including the second portion 8b until the end.
This is because separation of the second portion is likely to occur rapidly, and as a result, fingers are likely to be injured in either case.

The present invention is not limited to the above embodiments, and the score portion may have a shape other than a circle, such as a teardrop shape as shown at 8 in FIG. 7, for example. Further, the easy-to-open lid may be of a type that is joined to the container body by double seaming instead of a cap.

The easy-to-open lid that is opened by tearing off the annular score defining the opening panel using the knob of the present invention is designed so that the residual thickness of the annular score is initially cut close to the fixing tool of the knob. between the neighboring part including the first part, the neighboring part including the first part and the second part,
The thickness increases stepwise in the order of the middle part, which includes the part where the interval between the annular score parts in the direction perpendicular to the straight line connecting the first part and the second part is maximum, and the neighboring part, which includes the second part. ing.

The second portion and its neighboring portion are circular arc portions with the second portion in the center and a central angle (θ) of 30 to 100 degrees.

Therefore, the remaining thickness of the first portion and its neighboring portions is the smallest, and initial cutting is easy. In addition, if the residual thickness is uniform, the residual thickness at the middle part where the tear resistance is particularly high is also relatively small, so tearing at the middle part is relatively easy. Since the remaining thickness of the second part and its neighboring parts is relatively large, a relatively large resistance is generated when the second part is separated, so that the opening panel attachment does not suddenly separate from the top plate.

Therefore, in the easy-to-open lid of the present invention, the opening by initial cutting and tearing of the score part is performed smoothly until the end, and the part _3a1 facing the nose part of the knob part is the second part of the annular score part. Although the opening is close to the opening 8b, there is no risk of injuring the fingers when opening the opening.

[Brief explanation of drawings]

FIG. 1 is a plan view of an easy-to-open lid that is an embodiment of the present invention (if the remaining thickness of the score portion is uniform in the circumferential direction, it is a conventional easy-to-open lid), and FIG. Figure 3a is a vertical cross-sectional view taken along the - line in Figure 2, showing the cross-sectional shape of the score portion, and Figure 3b is a longitudinal cross-section of the main part showing an example of a defective deformed score portion. Figure 4 is a longitudinal sectional view showing the lid in Figure 1 while it is being opened, Figure 5 is a perspective view showing the relationship between the opening panel section and fingers after opening, and Figure 6 is the lid in Figure 1. FIG. 7 is a plan view showing an example of the score portion of the easy-to-open lid of the present invention, which is different from that shown in FIG. 1. 1...Easy-opening lid, 3...Knob tab, 3a...Knob part, 3a ₁ ...Part facing nose part, 3b...
...Nose part, 7... Opening panel part, 8... Annular score part, 8a... First part, 8b... Second part, 9... Rivet part (fixing tool), 10... First
11...intermediate part,
11a, 11b...The part where the interval between the annular score parts is maximum, 12...The neighboring part including the second part.

Claims (1)

[Claims] 1. In an easy-to-open lid that is opened by tearing an annular score portion that defines an opening panel portion using a grip tab, the grip tab is fixed to the opening panel portion in close proximity to the first portion of the annular score portion. A fastening device is formed for the purpose of the present invention, and the tab has a ring-shaped tab and a nose portion for initially cutting the first portion of the annular score portion, and the tab is opposite to the nose portion of the tab. The portion is proximate to a second portion of the annular score portion opposite the first portion of the annular score portion, and the annular score portion is adjacent to a portion thereof including the first portion and a portion thereof including the second portion. It consists of two intermediate parts including a neighboring part and a part between both neighboring parts where the interval between the annular score parts in the direction perpendicular to the straight line connecting the first part and the second part is maximum. , the residual thickness of the annular score portion becomes thicker stepwise in the order of the first portion including the first portion, the intermediate portion, and the second portion including the second portion. The easy-to-open lid is characterized in that the adjacent portion is an arcuate portion with a central angle (θ) of 30 to 100 degrees, with the second portion located at the center.