JP4925367B2 - Glass bottle - Google Patents

Description

  The present invention relates to a glass bottle in which a plurality of knurlings (projections) are provided in parallel in the circumferential direction along the outer peripheral edge of the bottle bottom.

A protrusion called a knurling is usually formed on the bottom of the glass bottle. This is mainly to reduce defects (minute cracks) caused by thermal shock when the glass bottle immediately after molding is placed on the conveyor and mechanical shock in the subsequent process. That is, the knurling comes into contact with the conveyor surface, and the contact area is reduced, so that the occurrence of defects is reduced. Accordingly, since the area where the lowermost part of the outer surface of the knurling (so-called grounding portion) contacts the mounting surface should be as small as possible, the grounding portion is configured by a curved surface so as to be substantially point contact with the mounting surface. It is desirable.
There are various shapes of the knurling, but most of them are formed radially in parallel at a predetermined interval on the outer peripheral portion of the bottom surface (radial direction or a direction slightly inclined from the radial direction) (FIGS. 4 and 5).
Such knurling is described in Patent Document 1 below, for example.

In addition, when a glass bottle is filled with a liquid content (beverage, seasoning, etc.) and distributed, the glass bottle may be destroyed due to a water hammer phenomenon. This is because, for example, when a carton filled with a glass bottle is lowered, when the glass bottle is lowered rapidly, the inner solution stays in inertia, so the bottom of the bottle becomes negative pressure and vacuum bubbles are generated. The solution falls abruptly and collides with the bottom, and the bottle is destroyed by the impact.
A bottle shape resistant to the impact of such a water hammer is described in Patent Document 2 below.

JP 2006-264715 A Japanese Patent No. 3644215

In general, the strength against the water hammer can be increased by increasing the radius of curvature in the longitudinal section of the bottle bottom surface.
The broken line in FIG. 5 is a superposition of the shape of the bottle 2 main body (part other than the knurling) and the shape of the knurling 21 (both are contour lines in the radial longitudinal section), and the solid line is the curvature of the skirt. A bottle 3 main body shape and a knurling 31 shape when the radius is increased to R1.
In the case of the radius of curvature R2 of the skirt, A2 is the lowest part of the bottle body, B2 is the lowest part of the knurling, and the distance (radius) a from A2 and B2 to the center of the bottle is equal.
In the case of the curvature radius R1 of the skirt, A1 is the lowest part of the bottle body, B3 is the lowest part of the knurling, and the distance (radius) b from A1 and B3 to the bottle center is equal.
Thus, conventionally, the radial position of the lowermost part of the knurling and the lowermost part of the bottle body has been designed to be equal.
As is apparent from FIG. 5, when the curvature radius of the skirt is increased, the radius (grounding radius) at the lowermost position of the knurling is decreased (b <a).

FIG. 4 shows a bottle which is relatively tall with respect to the outer diameter on the left side (a large aspect ratio) and a bottle which is relatively short on the right side. The fall angle is the angle of the bottle axis with respect to the vertical line when the bottle is gradually tilted and begins to fall.
Tall bottles are easy to fall down, so the radius of curvature of the hem is relatively small so that the ground contact radius is as large as possible and the fall angle is as large as possible.
Take a bottle with an outer diameter of 52 mm and a height of about 151 mm as a tall bottle, and a bottle with an outer diameter of 58 mm and a height of 120 mm as an example of a short bottle.
The tall bottle has a radii of curvature of 5 mm and a fall angle of 17 °.
The short bottle has a radii of curvature of 7 mm and a tipping angle of 21 °.

Tall bottles have a small radius of curvature at the skirt, so that when the water hammer phenomenon occurs, a large internal stress is generated and is easily broken.
If the radius of curvature of the hem of the tall bottle is increased from 5 mm to 6 mm, the glass thickness of the hem or bottom increases by 0.3 mm and the strength increases.
When the maximum generated stress is calculated when the dynamic pressure of the inner solution is 2 MPa due to the water hammer phenomenon, it is 114.4 MPa when the curvature radius of the skirt is 5 mm and 92.1 MPa when the curvature radius of the skirt is 6 mm. If the maximum generated stress is greater than 100 MPa, the risk of water hammer failure is high. Therefore, the risk of water hammer failure is high when the radius of curvature of the skirt is 5 mm, and the risk is low when it is 6 mm.

  However, as shown in FIG. 5, when the radius of curvature of the skirt is increased, the radius b of the lowermost position of the knurling is reduced, so that the fall angle is reduced from 17 ° to 15.5 °, and on the production line. There is a problem that many bottles fall and are not practical.

  It is an object of the present invention to improve the water hammer strength of a relatively tall bottle so that the falling angle does not decrease even if the radius of curvature of the hem is increased in order to increase the water hammer strength. To do.

In the present invention, a plurality of radial knurlings are provided in parallel along the circumferential direction along the outer peripheral edge of the bottle bottom, and the lowermost part of the outer surface of the knurling is substantially in point contact with the mounting surface. In the central longitudinal section along the longitudinal direction of the knurling , the lowermost portion is located radially outward from the lowest portion of the outer bottom surface of the bottle bottom where the knurling is not formed. The glass bottle is characterized in that the radius of curvature of the outline is larger in the inner part than in the outer part . (Claim 1)

  Since the bottom part of the knurling is outside the bottom part of the bottle body, even if the radius of curvature of the hem is increased and the bottom part of the bottle body moves inward, the bottom part of the knurling remains the same as before, Can be reduced.

  The difference between the radius of the lowermost position of the knurling and the radius of the lowermost position of the bottle body (ab in FIG. 2) is suitably about 0.75 to 1.5 mm.

  If the lowermost part of the knurling is positioned outside the lowermost part of the bottle body, the position of the lowermost part of the knurling will be greatly moved closer to the inner side in the longitudinal direction of the knurling, and defects (chips, cracks) will occur due to impact. It becomes easy. When the radius of curvature of the outer line of the knurling is made larger at the inner part than at the outer part, the position of the lowermost part approaches the center of the knurling and the occurrence of defects due to impact is reduced.

The knurling longitudinal direction may be inclined with respect to the radial direction as well as the radial direction of the glass bottle (Claim 2 ). (Claim 3 )
In this case, the inclination of the knurling with respect to the radial direction is about 45 ° or less.

  In the glass bottle of the present invention, the lowermost part of the outer surface of the knurling is positioned radially outward from the lowermost part of the outer surface of the bottle body where no knurling is formed, so that the radius of curvature of the hem of the bottle is increased in order to increase the water hammer strength. Even if is increased, the fall angle does not decrease. Therefore, the water hammer strength of a relatively tall bottle can be improved.

It is the bottom view of the glass bottle 1 of an Example, and its partial enlarged view. It is AA sectional view explanatory drawing in FIG. It is the bottom view of the glass bottle 1 'of an Example, and its partial enlarged view. It is a side view of a glass bottle. It is explanatory drawing of the knurling of the conventional glass bottle.

  As shown in FIG. 1, the knurling 11 of the glass bottle 1 of the embodiment is provided with the longitudinal direction thereof facing the radial direction of the glass bottle. In FIG. 1, the entire bottom surface of the glass bottle is shown on the upper side, and a part thereof is shown enlarged on the lower side.

FIG. 2 is an explanatory diagram of a cross section (radial direction cross section) taken along line AA in FIG. In FIG. 2, a solid line indicates a main body shape and a knurling contour line (radial direction cross section) in the vicinity of the skirt of the glass bottle 1. The thick broken line shows the main body shape of the conventional glass bottle 2.
The conventional glass bottle 2 is a round bottle having an outer diameter of 52 mm and a height of about 151 mm, and the curvature radius R2 of the skirt is 5 mm. The lowermost part A2 of the bottle body (portion other than the knurling) and the lowermost part B2 of the knurling 21 (FIG. 5) are both located directly below the center O2 of the arc curve of the skirt, which is a = 20.85 mm outside. Therefore, the grounding radius of the bottle is 20.85 mm and the falling angle is about 17 °.

In the glass bottle 1 of the example, the radius of curvature R2 = 5 mm of the bottom of the conventional glass bottle 2 is increased to R1 = 6 mm. The lowermost part A1 of the bottle body is located directly below the center O1 of the arcuate curve at the skirt, which is b = 19.9 mm outside the axis of the bottle. This has moved 0.95 mm inside from the lowest A2 of the conventional bottle body.
According to the conventional way of thinking, the knurling applied to the glass bottle 1 is provided so that the lowermost part B3 is located directly below the center O1 of the arcuate curve at the bottom as shown by a thin broken line (reference numeral 31). It is done. Since B3 is b = 19.9 mm outside the bottle axis, the grounding radius of the bottle is 19.9 mm, and the grounding radius is 0.95 mm smaller than that of the conventional glass bottle 2, making it easy to fall down (falling angle 15.5 °).

  However, in the knurling 11 of the glass bottle 1 of the embodiment, the lowermost part (grounding part) B1 is directly below the center of curvature O2 of the bottom part of the conventional glass bottle 2 (outer in the radial direction than the lowermost part A1 of the glass bottle 1 main body). ), The ground contact radius is the same as that of the conventional bottle 2, a = 20.85 mm, and the falling angle is about 17 °, which is not easy to fall.

The lowermost part of the outer surface of the knurling 11 is formed of a curved surface so as to substantially make point contact with the mounting surface.
Further, in the contour line of the longitudinal section of the knurling 11, the curvature radius R4 of the inner part with the lowermost part B1 as a boundary is 2 mm larger than the curvature radius R3 of the outer part. For this reason, the lowermost part B1 of the knurling 11 is located near the center in the longitudinal direction of the knurling.

FIG. 3 shows the bottom surface of a glass bottle 1 ′ according to another embodiment, and the knurling 11 ′ is provided with its longitudinal direction inclined with respect to the radial direction of the glass bottle. Also in this case, as in the case of the above-described embodiment, the lowermost part of the outer surface of the knurling 11 'is formed of a curved surface so as to be substantially in point contact with the mounting surface, and the lowermost part is formed with a knurling. It is located on the outside in the radial direction from the lowest part of the outer surface of the bottle body in the part that is not. Similarly to the above embodiment, in the central longitudinal section (BB cross section) along the longitudinal direction of the knurling 11 ′, the inner radius of the outer wall is larger than the outer radius.

1 Glass Bottle 11 Knurling 1 'Glass Bottle 11' Knurling 2 Glass Bottle 21 Knurling 3 Glass Bottle 31 Knurling

Claims (3)

A plurality of radial knurlings are provided in parallel along the circumferential direction along the outer periphery of the bottle bottom,
The outermost part of the outer surface of the knurling is constituted by a curved surface so as to be substantially in point contact with the mounting surface,
The lowermost portion is located radially outward from the lowermost portion of the outer bottom surface of the bottle bottom where the knurling is not formed ,
A glass bottle characterized in that, in a central longitudinal section along the longitudinal direction of the knurling, the inner radius of the outer radius is larger than the outer radius . The glass bottle according to claim 1, wherein a longitudinal direction of the knurling faces a radial direction of the glass bottle. The glass bottle according to claim 1, wherein a longitudinal direction of the knurling is inclined with respect to a radial direction of the glass bottle.

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