JPH0321423B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a can end plate that can withstand relatively high internal pressure, and is used in the field of manufacturing cans.

(Prior Art/Problems) When a can is filled with a sparkling beverage such as beer or cola or a gas for spraying paint or the like, the can is subjected to a large internal pressure. Since the can body has a circular cross section, it is difficult to deform even when subjected to relatively large internal pressure.
Since the bottom plate of the end plate is a flat plate, it is susceptible to internal pressure and may deform outward into a convex shape. Such deformation is a major problem with aluminum end plates having low rigidity.

In order to solve this problem, it has been proposed to provide an annular bead on the end plate, but the effect is small, and if it is made of aluminum, it will actually be 0.3
A plate thickness of mm or more was required.

(Means for Solving the Problems) The first invention of this application provides an annular bead at the peripheral edge of a metal bottom plate whose end plate has a planar circular outer shape, and the inner wall of the groove is formed into a planar polygonal outer shape. That is.
The reason why the planar surface is polygonal is to receive internal pressure intensively at each top, and there is no particular limitation on the number of angles, but in practice, for end plates of the size shown in the following examples, it is 8 to 8. Approximately 20 squares is appropriate.

A second invention of this application is, in addition to the first invention, in that a reinforcing bead is provided on the outer side of the lower part of the rising peripheral wall of the outer periphery of the end plate. The reinforcing bead is for preventing the peripheral wall from curling up due to internal pressure, and may be a continuous annular bead or an intermittent bead. When provided continuously, it is preferable to provide them facing each vertex of a planar polygon.

(Function) When the end plate is subjected to internal pressure exceeding the limit, it deforms protrudingly, but during deformation, the peripheral edge forms a polygonal shape (No. 5
figure). In the present invention, since the inner walls of the grooves are formed into planar polygons in advance, the internal pressure is concentrated at each top. Since each top portion has relatively high strength, the pressure resistance of the end plate is improved and it becomes difficult to deform.

Further, according to the second invention, deformation of the peripheral wall is prevented by the reinforcing bead.

Embodiments of the present invention will be described below based on the drawings.

(Example) Planar circular bottom plate 1 made of aluminum (diameter 55.5
In the end plate 3, which has a continuous peripheral wall 2 standing up on the outer circumference of
(depth 3 mm), and the inner wall 5 of the bead 4
is a plane dodecagon. Furthermore, reinforcing beads 7 are provided intermittently on the outer side of the lower part of the peripheral wall 2, facing each top 6 of the inner wall 5.

In the above, the reinforcing bead 7 of the rising peripheral wall 2
If it is not provided, it will be the first invention.

The end plate 3 of this embodiment is used by being fixed to the can body 8, and the outer surface of the peripheral wall 2 and the inner surface of the can body 8 are usually bonded together via a heat-welding resin.

Next, the strength of the end plate shown in the above embodiment and the strength of a conventional end plate will be compared and explained.

(1) The structure of each sample is as follows.

Γ Sample 1: No reinforcement means applied to either the bottom plate or the peripheral wall Γ Sample 2: An annular bead (depth 3 mm) is provided on the peripheral edge of the bottom plate Γ Sample 3: Among the above examples, there is no reinforcing bead (the first Invention) Γ Sample 4 of the above embodiment (second invention) (2) The materials of each sample are as follows. Varnish/hard aluminum (H18), thickness
130μ/Low density polyethylene, thickness 70μ (inner can) (3) Test method Each sample above was tested on a paper can body (diameter 57mm, height 97mm).
mm), the inside of the can was pressurized by a compressor, and the deformation and detachment of the end plates were tested. The fixing structure is as shown in FIG. 6, and the peripheral wall of the end plate and the inner wall of the can body are thermally welded.

(4) Comparison Results Γ Sample 1 The end plate separated from the can body at an internal pressure of 0.6 to 0.8 Kgf/cm ² and was significantly deformed as shown in FIG. In addition, the peripheral wall was pulled up by the protruding deformation of the bottom plate and was turned up significantly toward the center.

Γ Sample 2 At an internal pressure of 0.9 to 1.0 Kgf/cm ² , the end plate separated from the can body and was deformed in a protruding manner. Furthermore, the peripheral wall was pulled toward the center by being pulled due to the protruding deformation of the bottom plate.

Γ Sample 3 Although the end plate separated from the can body under an internal pressure of 1.2 to 1.4 Kgf/cm ² , almost no protruding deformation was observed. However, the surrounding wall was pulled slightly toward the center.

Γ Sample 4 Although the end plate separated from the can body under an internal pressure of 1.4 to 1.5 Kgf/cm ² , almost no protruding deformation was observed. Furthermore, the portion of the peripheral wall below the reinforcing bead was only slightly pulled toward the center.

From the above comparison results, it is clear that this example has the following effects.

According to the first invention, since the inner wall 5 of the annular bead provided on the bottom plate is a planar polygon, internal pressure is concentratedly applied to each top 6 of the polygon. Since the three ridge lines 9, 10, and 11 intersect at the top 6, the deformation resistance is large, and the deformation force acts in the direction indicated by the arrow 12 in FIG. Therefore, protruding deformation of the bottom plate is prevented as much as possible.

Further, according to the second invention, even when the bottom plate 1 is slightly deformed and the lower part of the peripheral wall 2 is pulled in the direction of arrow 13 in FIG. No deforming force is transmitted above. Therefore, the peripheral wall above the reinforcing bead 7 is not deformed, and separation of the heat-welded portion from the can body due to deformation (turning up) of the peripheral wall can be prevented.

Incidentally, since the deforming force is largely applied to the opposing portions of each top portion 6, it is effective to provide the reinforcing bead 7 opposite to each top portion 6.

(Effects of the Invention) According to the first invention, it is possible to improve the strength against internal pressure that causes the bottom plate of the end plate to protrudely deform.

Moreover, according to the second invention, deformation of the peripheral wall can be further prevented as much as possible.

Therefore, according to the present invention, it is possible to obtain an end plate that can withstand relatively large internal pressure due to beer filling, etc., using a material with extremely low rigidity, such as a thin aluminum plate. If an aluminum plate with a thickness of about 0.1 mm is used for the end plate, opening is easy, and there is also the advantage that a synthetic resin opening knob can be used.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the embodiment of the invention, FIG. 2 is a front view, FIG. 3 is a sectional view, FIG. 4 is a bottom view, and FIG. 5 is a plan view showing a modification of the conventional product. FIG. 6 is a sectional view showing the fixing structure of the end plate. 1...Bottom plate, 2...Peripheral wall, 3...End plate, 4...Bead,
5...Inner wall, 6...Top, 7...Reinforcement bead.

Claims (1)

[Scope of Claims] 1. An end plate for a can, characterized in that an annular bead 4 is provided at the periphery of a metal bottom plate 1 having a planar circular outer shape, and the inner wall of the bead 4 is a planar polygon. 2. The end plate of a can according to claim 1, wherein the material of the end plate 3 is an aluminum plate. 3. An annular bead 4 is provided on the peripheral edge of the metal bottom plate 1 having a planar circular outer shape, and the inner wall of the bead 4 is made into a planar polygonal shape, and the lower outer side of the rising peripheral wall 2 connected to the bottom plate 1 is reinforced. An end plate of a can characterized by being provided with a bead 7. 4. The can end plate according to claim 3, wherein the reinforcing beads 7 are provided intermittently or continuously. 5. The can end plate according to claim 3, wherein the intermittent reinforcing beads 7 are provided opposite to each vertex of a polygon formed on the bottom plate 1.