JPS604783Y2 - Tail plug for ink storage tube of ballpoint pen, etc. - Google Patents

Description

[Detailed description of the invention] This invention is fitted to the tail end of an ink storage tube called a refill used in ballpoint pens, etc., to ensure ventilation, and when the ink flows back, the ink flows out of the storage tube. This invention relates to the improvement of a tail plug made of powdered sintered metal that prevents leakage, and aims to provide a tail plug that does not cause clogging of the porous structure of the end surface even when subjected to finishing or fitting processing. The purpose is

A tail plug made of powdered sintered metal is already known, which is fitted to the tail end of an ink storage tube such as a ballpoint pen to ensure ventilation inside and outside the tube and to prevent backflow of ink. Sintered metal tail plugs cannot have gentle slopes at the corners due to manufacturing constraints, and are prone to cracking at the parting line. It is difficult and has poor productivity.

For this reason, barrel polishing is performed to smooth the corners and remove the burr, but during barrel polishing, the porous structure on the surface of the tail plugs gets clogged due to joint rubbing between the tail plugs and friction with the abrasive grains. There is a disadvantage that air permeability is lost due to
The pressure applied when fitting the ink storage tube into the ink storage tube also destroys the porous structure of the end surface, resulting in a loss of air permeability.

The present invention provides a tail plug made of powdered sintered metal that does not have the above-mentioned drawbacks by having the configuration described in the claims of the utility model registration.

The configuration of the illustrated example will be explained below.

FIG. 1 is an enlarged vertical sectional view of an ink storage tube 2 for a ballpoint pen using a tail plug 1 made of powdered sintered metal according to the present invention. The tail plug 1 is press-fitted.

As shown in FIG. 2, the tail plug 1 is formed into a short cylindrical body 5 made of powdered sintered metal, and has conical recesses 8 and 9 recessed in the center of both end surfaces 6 and 7. There is.

For this reason, barrel polishing is performed after molding, and the corner 10.11
The parting line part 12. is finished smoothly.
When removing the burrs that occur in 13 etc., the porous structure of the circumferential surface or both end surfaces 6 and 7 of the short cylinder 5 becomes clogged due to mutual rubbing between the tail plugs and friction with the abrasive grains, resulting in poor air permeability. However, there is no risk of damage to concave drafts 8 and 9.
There is no clogging of the porous structure and no loss of air permeability.

In addition, as shown in FIG. 1, a tail plug 1 is attached to the tail end of the tube body 4.
When press-fitting the end face 14, for example, the second
Even if the porous structure of the end face 6 shown in the figure is destroyed and air permeability is lost, the peripheral surface inside the concave guide 8 will not be pressed and the porous structure will not be destroyed, so air permeability will be improved. never be lost.

Moreover, since sufficient barrel polishing can be performed, the angle of 10.1
1 can be sufficiently chamfered, burrs can be completely removed, and press-fitting into the tube body 4 can be performed smoothly and efficiently.

As described above, according to the present invention, even if the barrel is sufficiently polished or a strong pressing force is applied for press-fitting into the tail end of the tube, the tail end will not work even if it is made of powdered sintered metal. It is possible to achieve the effect of always ensuring air permeability from end surface to end surface of the stopper.

Although the concave portions 8 and 9 in the illustrated embodiment have a conical shape, it is needless to say that they are not limited to this shape.

[Brief explanation of drawings]

FIG. 1 is an enlarged longitudinal cross-sectional view of an ink storage tube, and FIG. 2 is an enlarged side view partially in section of one embodiment of the present invention. 1... tail plug, 2... ink storage tube, 5
...Short cylindrical body, 6,7...Both end faces, 8,
9... Concave confectionery.

Claims (1)

[Scope of utility model registration request] A tail plug for an ink storage tube of a ballpoint pen, etc., characterized in that a short cylindrical body formed of powdered sintered metal has concave ribs formed on both end faces thereof.