JPS5855929Y2 - test tube metal cap - Google Patents

Description

[Detailed description of the invention] This invention relates to a metal cap that is placed over a test tube.

The metal cap is made of a metal plate such as aluminum, and the cylindrical peripheral wall and the earthen wall are integrally formed by drawing process.In order to maintain air permeability, there are multiple holes on the inner side of the earthen wall that abut against the upper end of the test tube. It has a structure in which a protrusion is provided to form a ventilation gap between the inner surface of the earthen wall and the upper end of the test tube.

The protrusions provided on the inner surface of the earthen wall are formed integrally during the drawing process of the metal cap, but in this case, if the protrusions are provided on the periphery of the earthen wall so as to reach the surrounding wall, the bent portions of the surrounding wall and the earthen wall will form a protrusion. The wall becomes extremely thick in this area, and during drawing, stress is concentrated in this area and cracks occur.

To prevent such cracks from occurring, it is possible to reduce the wall thickness by pushing the protrusion part from the opposite side during drawing, but this creates a recessed part on the outer surface of the cap, which affects the appearance. Undesirable.

Therefore, it was necessary to provide the protrusion at a position closer to the center than when manufacturing a metal cap by drawing.

However, because test tubes have errors in diameter and thickness, when the cap is placed on the cap, the protrusion may not fit onto the top of the test tube, and the portion between the protrusion and the peripheral wall may fit onto the top of the test tube.

When such a fit occurs, the inner surface of the top plate comes into contact with the upper end of the test tube, causing a problem in that the inside of the test tube is sealed and air permeability cannot be maintained.

This invention was developed to solve the above-mentioned problems, and its purpose is to provide a metal cap that can reliably maintain ventilation even if there are errors in the test tube.

Hereinafter, embodiments of this invention will be described based on the accompanying drawings.

As shown in the figure, the cap 1 is made of a metal material such as aluminum, and has a cylindrical peripheral wall 2 and an upper wall 3 integrally formed.

A plurality of projections 4 (four in the illustrated case) are provided on the inner surface of the upper wall 3 at positions closer to the center than the peripheral wall 2.

In the illustrated case, the protrusion 4 is long in the radial direction of the upper wall 3, and is formed in such a shape that the center part protrudes the most, and when it is placed over the test tube A, the protrusion 4 rests on the upper end of the test tube A, and the upper wall A gap for ventilation is formed between the inner surface of No. 3 and the upper end of the test tube.

On the inner surface side of the upper wall 3, a bulging portion 5 whose protrusion amount is smaller than that of the projections 4 is provided between the peripheral wall side end portion of each projection 4 and the peripheral wall 2.

This bulging portion 5 allows the upper wall 3 and the upper end of the test tube to come into contact when there is an error in the test tube A and the protrusion 4 and the peripheral wall 2 fit into the upper end of the test tube A (see Figure 1). This creates gaps for ventilation.

The protrusion 4 and the bulging portion 5 are integrally formed when the cap 1 is drawn.

In this case, the protrusion 4 with a large protrusion amount is provided at a position closer to the center than the peripheral wall 2, and the bulge portion 5 formed at the end of the upper wall 3 has a smaller protrusion amount than the protrusion 4, and during drawing process. Since the wall thickness is such that stress does not concentrate locally in the bent portions of the peripheral wall 2 and upper wall 3, cracks do not occur in the bent portions of the peripheral wall 2 and upper wall 3, and the outside There is no need to push it in from the beginning.

The metal cap of this invention has the above-mentioned structure, and when it is placed over the test tube A, the protrusion 4 normally rests on the upper end of the test tube A, creating a gap between this upper end and the upper wall 3. , the ventilation state is maintained through the fitting gap between the peripheral wall 2 and the test tube A.

Further, as shown in FIG. 1, even if the protrusion 4 and the peripheral wall 2 fit together at the upper end, the bulge 5 can maintain the ventilation state.

As described above, according to this invention, a protrusion for maintaining ventilation is provided at a position closer to the center than the peripheral wall on the inner surface side of the soil wall of the metal cap, and a protrusion with a smaller protrusion than the protrusion is provided between the protrusion and the peripheral wall. Since the bulge is formed, even if there are errors in the diameter or wall thickness of the test tube, the air permeability inside the test tube can be maintained at all times.

Furthermore, since the bulging portion has a small protrusion amount, it can be formed without concentrating stress on the bent portion of the earthen wall of the peripheral wall during the drawing process, which has the effect of providing a product that is easy to form and has a good appearance.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the metal cap, FIG. 2 is a perspective view of the metal cap, and FIG. 3 is a bottom view of the metal cap. 1...Metal cap, 2...Peripheral wall, 3
...Top wall, 4...Protrusion, 5...
・Bulge.

Claims (1)

[Scope of utility model registration request] In a metal cap that is made by integrally molding a surrounding wall and a clay wall and is placed over the top end of a test tube, a plurality of protrusions are provided on the inner surface of the clay wall at a position closer to the center than the surrounding wall, and the end of each protrusion on the circumferential wall and the surrounding wall A metal cap for a test tube characterized in that a bulge having a protrusion less than the protrusion is formed between the metal cap and the protrusion.