JPS6246432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cap and a method for assembling the cap.

Recently, synthetic resin bottles have been widely used. The bottle is
It has the advantage of being lighter and less likely to break than glass bottles. By making the synthetic resin bottle thinner, the material can be saved. For example, a biaxially stretched saturated polyester resin bottle can have its mechanical strength increased by biaxially stretching. However, when such thin-walled synthetic resin bottles are filled with heat-sterilized liquid and then capped and sealed, the volume decreases due to cooling of the filled liquid, and the air above the liquid level inside the bottle, the so-called head space. A certain drop in the temperature of the air causes a negative pressure inside the bottle, and this negative pressure causes the bottle wall to curve inward. The decompression deformation occurs not only when high-temperature liquid is filled, but also when oxygen in the head space is absorbed by the filling liquid. An example of such a liquid is edible oil.

In order to prevent deformation of synthetic resin bottles under reduced pressure, a deformation-permissible portion is provided in advance on the bottle wall, and only the deformation-permissible portion is deformed into a concave shape so that the appearance of the bottle is not impaired. However, this method has the drawbacks that there are major restrictions on the design of the bottle, the place where the label can be applied is also restricted, and furthermore, the wall thickness of the bottle cannot be made sufficiently thin.

However, the above-mentioned prevention of deformation due to reduced pressure can be solved by filling the head space of the bottle with high-pressure air or the like in advance in anticipation of the reduced pressure.

The present invention relates to a cap that can be filled with high-pressure gas and a method for assembling the cap. First, the cap will be explained.

The cap 1 is screwed or not screwed into the neck part 22 of a biaxially stretched saturated polyester resin bottle 21, for example, and the cap includes a first member A for forming the cap, and a first member A for forming the cap. and a second member B for use.

The first member A is made of an elastic synthetic resin material. The member has a spherical portion 2 having an outer diameter that is approximately the same as the inner diameter of the bottle neck portion 22 and has a convex upper surface that can be elastically reversed downward, and from the outer circumferential portion of the spherical lower surface, A highly elastic short cylindrical portion 3 for sealing the inner surface of the upper end of the neck of the bottle is vertically tapered downward,
Further, from the outer periphery of the spherical part, an outward flange part 6 is protruded through the bent part 4 and has a width substantially the same as the wall thickness of the top surface of the bottle mouth and has an appropriate number of protrusions 5 on the lower surface. It is something that The outer diameter of the outward flange may be the same as or slightly larger than the outer diameter of the top surface of the bottle. The first member is provided so that when the outward flange portion is placed on the top surface of the bottle mouth and the spherical portion 2 is reversed downward, the outer surface of the short cylindrical portion comes into pressure contact with the inner surface of the neck of the bottle mouth to form a seal. It is.

The second member B has a top plate portion 11 that covers the upper surfaces of the spherical portion and the outward flange portion 6 of the first member, and the outer surface of the neck of the bottle is exposed from the peripheral edge of the top plate portion. It is a thin metal plate member having a vertically disposed peripheral wall 12 to be covered. The peripheral wall is provided so that it can be drawn.

In order to create high pressure in the head space inside the bottle using the cap configured as described above, the cap is temporarily fitted to the neck of the bottle as shown in Fig. 1, and a packing 15 is attached to the bottom end. cylinder 16
The packing is pressed against the upper surface of the bottle shoulder and fitted, thereby increasing the pressure inside the cylinder. The high pressure gas passes between the neck of the bottle and the cap and increases the pressure in the head space, so in this state the upper surface of the top plate 11 above the spherical part is pushed down with a push rod or the like. Then, the spherical part 2 is reversed and seals the bottle opening, so the cylinder is removed and the peripheral wall 12 of the second member is removed.
The engaging portion 13 may be formed by narrowing the thread 23 or the engaging protrusion 13 attached to the outer surface of the mouth and neck.

The present invention has the above-mentioned structure, and the cap is composed of a first member and a second member, and the first member has a spherical part 2 which can be elastically reversible, and a downward slope extending from the outer periphery of the lower surface of the spherical part. A short cylindrical part 3 with high elasticity is vertically installed in a tapered shape, and an outward flange-like part 6 having an appropriate number of protrusions 5 on the lower surface protrudes from the outer periphery of the spherical part through the bent part 4. The second member covers the upper surfaces of the spherical part and the outward flange part with a top plate part 11, and has a peripheral wall 12 that can be drawn suspended from the periphery of the top plate part. Since it is made of a thin metal plate, it is easy to inject high-pressure gas into the bottle head space when the cap is fitted to the neck of the bottle, and it is also easy to seal the bottle mouth. By drawing the peripheral wall 12, detachment of the cap can be prevented. Furthermore, after the cap is completely fitted, the top plate portion of the second member above the spherical part 2 is curved downward in a concave shape along the upper surface of the spherical part which has been turned downward. Even if the stored liquid pushes the spherical part from the inside to the outside when it falls over, since the top plate part is deformed, the spherical part will not flip upward, and the stored liquid will not leak out. do not have.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing the cap according to the present invention temporarily fitted to the neck of the bottle to generate high pressure in the head space of the bottle; FIG. A...first member, B...second member, 1...cap.

Claims (1)

[Scope of Claims] 1. A spherical portion 2 having an outer diameter that is approximately the same as the inner diameter of the bottle neck portion 22 and having a convex upper surface that can be elastically inverted downward; , a highly elastic short cylindrical part 3 for sealing the inner surface of the upper end of the neck of the bottle, which is vertically disposed in a downwardly tapered shape; an outward flange-shaped part 6 having a width substantially the same as the wall thickness and having an appropriate number of protrusions 5 on the lower surface; a first cap-forming member A made of an elastic synthetic resin formed of; The upper surfaces of the spherical part 2 and the outward flange part 6 are covered by a top plate part 11, and a peripheral wall 12 which can be drawn and can be drawn is hung from the periphery of the top plate part to cover the outer surface of the neck of the bottle. A cap comprising: a second cap-forming member B made of a thin metal plate; 2. A spherical part having an outer diameter that is approximately the same as the inner diameter of the neck of the bottle and having a convex upper surface that can be elastically inverted downward; A highly elastic short cylindrical part is provided for sealing the inner surface of the upper end of the bottle neck, and a short cylinder part with a thickness that is approximately the same as the thickness of the top surface of the bottle is attached to the outer periphery of the spherical part via a bent part. and an outward flange-shaped part having an appropriate number of protrusions on the lower surface; a first member for forming a cap made of synthetic resin; a cap-forming second member made of a thin metal plate having a circumferential wall hanging from the periphery of the top plate portion to cover the outer surface of the neck of the bottle; The flange-shaped portion 6 is placed on the top surface of the bottle, and the outer surface of the neck of the bottle is covered with the peripheral wall 12 of the second member, and in this state, a passage is made between the outer surface of the neck of the bottle and the inner surface of the cap. After filling the head space of the bottle with high pressure gas, press down the upper surface of the second member top plate 11 above the spherical part and invert the spherical part to seal the inner surface of the neck of the bottle with the short cylindrical part. A method for assembling a cap, which is performed by tightening the peripheral wall of the second member to form an engaging portion 13 for a thread or engaging protrusion attached to the outer surface of the neck of the bottle.