JPH0340752Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a metal cap, and more particularly to a metal cap used for sealing containers such as glass bottles.

Sealed bottles are made by hot filling a glass bottle with a beverage such as natural juice and sealing it with a metal cap.
Normally, the internal pressure is negative (that is, lower than atmospheric pressure), but if the beverage ferments and the internal pressure increases and becomes much higher than atmospheric pressure, the cap may pop out when you try to open it. Or, if the internal pressure exceeds the breaking strength of the bottle (which tends to happen particularly in the case of lightweight, thin-walled bottles), the bottle may burst and scatter, potentially causing harm to the human body. The object of the present invention is to provide a metal cap that can prevent the cap from flying out and the bottle from bursting in such cases.

In order to achieve the above object, the present invention includes a vent hole provided in the top plate, and a closure that is integrally connected to the top plate main body through a portion of the periphery of the vent hole that is to become a hinge part when venting. The present invention provides a metal cap characterized in that a piece closes the upper surface of the vent hole and the vicinity of its periphery, and is sealed with a sealing material at least at the periphery of the closing piece.

The present invention will be described below with reference to the drawings which are examples.

A metal cap 1 shown in FIG. 1 is a pilfer-proof cap equipped with a pilfer-proof band 2, and the shell body is formed from a metal plate such as an aluminum alloy plate.

The top plate 3 is provided with a central recess 3a, and a vent hole 4 is formed in the central recess 3a. A closing piece 6 is provided that is integrally connected to the top plate main body via a portion 5 of the peripheral edge 4a of the vent hole 4 that is to become a hinge portion during venting (see FIG. 7). The closing piece 6 closes off the vent hole 4 and the upper surface near its peripheral edge 4a. The space between the peripheral portion 6a of the closing piece 6 and the top plate body is sealed by a sealing material such as a resin layer 7 (for example, made of a gelled layer of plastisol). As a sealing material, like the metal cap 11 shown in FIG.
A piece of adhesive tape 17 may also be used. Furthermore, the second
In the figure, parts with the same reference numerals as in FIG. 1 indicate similar parts.

FIG. 3 shows that after a metal cap 1 is plugged into the mouth 9 of a glass bottle filled with natural juice, etc., and the bottle is sealed, the internal pressure increases, the vent hole 4 opens, and the gas 10 inside the bottle is sealed. Shows that the water is gushing out. That is, the resin layer 7 near the peripheral portion 6a of the closure piece 6 is broken or peeled off, and the closure piece 6 turns upward and to the right around the hinge portion 5, thereby opening the vent hole 4.

The type, thickness, and temperature of the resin in the resin layer 7 are adjusted so that the internal pressure at which the resin layer 7 ruptures or peels is lower (for example, 5 kg/cm ² ) than the lowest internal pressure at which the bottle bursts or the cap pops out (for example, 5 kg/cm 2 ). By determining the adhesive force with the plate and the length of the hinge part through experiments, the vent hole 4 opens before the cap pops out or the bottle bursts, thereby preventing the cap from popping out or the bottle bursting. It can be prevented.

Note that when the contents exhibit normal negative pressure, the closure piece 6 is sucked downward, but the peripheral part 6 of the closure piece 6
Since the lower surface of a is engaged with the top plate portion near the peripheral edge 4a of the vent hole 4, there is no fear that the closing piece 6 will fall into the interior, and the sealing performance by the sealing material is ensured. Furthermore, the recess 3a of the top plate 3 makes it possible to hold the sealing material such as the closing piece 6 and the resin layer 7 below the top surface of the top plate 3 without protruding from the top surface. This has the advantage that there is no risk of damage to the resin layer 7 etc. during handling or stacking.

The metal cap 1 is manufactured, for example, as follows.

First, as shown in FIG. 4, a metal shell 21 having a central bulge 23a and an annular recess 23b surrounding the central bulge 23a is formed on the top plate 23 by a conventional method. Next, as shown in FIG. 5, the vent hole 4 is cut along a line 4'a corresponding to the peripheral edge 4a, leaving a portion 5 that is to become a hinge portion. Next, as shown in FIGS. 6 and 7, the central bulge 23
a and the annular recess 23b are pressed to form a closing piece 6 which is flattened and whose peripheral portion 6a contacts the upper surface of the top plate portion near the peripheral edge 4a of the vent hole 4. After that, a resin layer 7 and a liner layer 8 are formed.
The metal cap 11 is manufactured in the same manner as described above.

The present invention is not limited to the above-mentioned embodiments, but can also be applied to, for example, pilfer-proof caps in a different form from that shown in FIG. 1, or metal caps in various other forms. Needless to say, it can also be applied to sealing plastic bottles.

The metal cap of the present invention can ensure sufficient sealing when the inside of the bottle is under negative pressure when it is sealed with a glass bottle, etc., and when the pressure inside the bottle is positive, the strength of the sealing material etc. must be determined appropriately. As a result, the vent hole opens before the cap flies out or before the bottle bursts, and it is possible to prevent the cap from flying out or the bottle from bursting or being scattered.

Furthermore, since the closing piece pivots around the hinge when opening the opening, there is no danger of the closing piece coming out. Furthermore, since the closure piece is formed integrally with the cap body, it has the advantage of low material costs.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a metal cap that is a first embodiment of the present invention, Figure 2 is a vertical cross-sectional view of a metal cap that is a second embodiment of the present invention, and Figure 3 is a vertical cross-sectional view of a metal cap that is a second embodiment of the present invention. Vertical sectional views showing the sealed metal cap of FIG. 1 in a vented state, FIGS. 4, 5, and 6.
7 are drawings showing an example of the process of manufacturing the metal cap shown in FIG. 1, FIG. 4 is a longitudinal cross-sectional view of the metal shell that is the raw material, and FIG. 5 shows the portion corresponding to the vent hole. FIGS. 6 and 7 are a longitudinal sectional view and a plan view, respectively, showing the state after the top plate is rolled out. FIGS. 1, 11...metal cap, 3...top plate, 4...
...Vent hole, 4a...Peripheral part, 5...Part that should become the hinge part, 6...Closing piece, 6a...Peripheral part,
7... Resin layer (sealing material), 17... Adhesive tape piece (sealing material).

Claims (1)

[Scope of utility model registration request] A vent hole is provided in the top plate, and a closing piece that is integrally connected to the top plate main body through a portion of the periphery of the vent hole that should become a hinge portion during venting is provided with a closing piece that connects the vent hole and its periphery. 1. A metal cap, characterized in that the upper surface of the cap is closed, and at least the periphery of the closure piece is sealed with a sealing material.