JP2000247087A - Tail plug for writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold air-tightness when a barrel is mounted with a structure as simple as possible, and to obtain a sufficient air flowing passage at a single tail plug by forming a continuous vent part made of a recess and/or a protrusion extended in a lengthy direction of a member at a liquidtight contact part of each member in the state that the members are separated. SOLUTION: The tail plug 1 is constituted of a plurality of members of a same shape. Since an outer diameter line of a cross section of a liquidtight contact part 7 is symmetrical to a center of the plug 1 while a protrusion and recess part is formed on the part 7, both the members coincide in a shape manner when both the members are connected to obtain a liquid tight contact. In the part 7, circular arc-like protrusion 8 and recess 9 are formed as a continuous vent part capable of communicating openings of both ends of the tube when it is inserted into the tube like a throat in a press injected state. Thus, air tightness is held when the shaft is mounted, and sufficient air vent passage can be obtained at the single plug.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument such as an oil-based marker, a line marker, and a water-based ball-point pen, which is attached to the rear end opening of a shaft cylinder containing ink therein in a press-fit manner. About.

[0002]

2. Description of the Related Art Conventionally, there is known a tail plug having a structure in which an air flow passage is provided so as not to suffocate even if the tail plug is swallowed by mistake. However, since it is attached to the rear end opening of the barrel of the writing instrument in which ink is stored, liquid-tightness and air-tightness are often required, and it is necessary to form an air flow passage for preventing suffocation. It was necessary to consider the relationship.

[0003]

However, in a tail plug that needs to maintain liquid-tightness and air-tightness in a writing instrument, a sufficient air flow passage for preventing suffocation is secured with the tail plug removed from the writing instrument. At present, it is not easy.
SUMMARY OF THE INVENTION An object of the present invention is to obtain a tail plug that has a simple structure, maintains airtightness when mounted on a shaft, and can secure a sufficient air flow passage by itself.

[0004]

That is, the present invention relates to a tail plug of a writing instrument which is press-fitted into a rear end opening of a shaft cylinder containing ink therein and comprises a plurality of separable members. Each member has a liquid-tight contact portion with respect to each other member and a liquid-tight pressure contact portion with respect to the inner wall of the barrel, and in a state where the liquid-tight contact portions are in contact with each other, the tail plug is joined. The outer periphery forms a circumferential liquid-tight pressure contact portion with respect to the inner wall of the barrel, and in a state where each member is separated, a concave portion extending in the longitudinal direction of the member at the liquid-tight contact portion of each member. A tail plug of a writing instrument characterized by forming a continuous ventilation section including a projection.

[0005]

In a state in which the writing implement is mounted by being pressed into a barrel or the like of the writing implement, a circumferential liquid-tight pressure-contact portion is formed with respect to the inner wall of the writing implement, and the contact state between the plurality of members is also in a state of contact with each other. When the close contact portion is in close contact with the writing instrument to secure liquid tightness and confidentiality, and is detached from the writing instrument, it is divided into a plurality of members and the concave and / or convex portions formed in the liquid tight contact portion. Since the continuous ventilation portion formed of the portion forms the outside of the member, breathing can be ensured even if the throat is accidentally clogged.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a longitudinal sectional view showing a main part of the tail plug 1 of the present invention in a state where the tail plug 1 is press-fitted and fixed to an opening at the rear end of a barrel 2 of a writing instrument. A liquid-tight forming part 3 and a display part 4 protruding outside the barrel 2.
The liquid-tight forming part 3 is formed with a ring-shaped convex part 5 as a circumferential liquid-tight pressure contact part, and the foremost part of the display part 4 comes into contact with the opening end of the barrel 2 to define a connection position. The collar 6 is provided. As shown in FIG. 2 which is a view in the direction of arrow I, the tail plug 1 is composed of a plurality of members having the same shape, and the contact portions of the members are liquid-tight contact portions 7. Since the liquid-tight contact portion 7 is formed so that the outer diameter line of the cross section thereof is point-symmetric with respect to the center of the tail plug 1 while the unevenness is formed, the liquid-tight contact portion 7 is used when joining both members. Liquid tight contact can be obtained in conformity with the shape.

The liquid-tight abutment 7 has an arc-shaped convex portion as a continuous ventilation portion through which openings at both ends of the tube can be communicated when inserted into a throat-like tube (not shown) in a press-fit state. 8 and a concave portion 9 are formed. FIG. 3 is an external view of one member of the tail plug 1 as viewed from the liquid-tight contact portion 7 side.
As shown in FIG. 5, the projection 8 and the recess 9 are formed with a projection 10 and a hole 11 for positioning when joining the members together, and the projection 10 of one member is connected to the other member. The holes 11 are fitted so that the members are not shifted and joined.

FIG. 4 shows another example of dividing the tail plug 1 into a plurality of members. This is shown as a diagram corresponding to FIG. This is an example in which members having the same shape are arranged and joined symmetrically with respect to the center of the tail plug 1. FIG. 5 shows an example of a case where the member is divided into members having different shapes. However, when members having different shapes are used, molding dies are required by the number of types of the members, and it is necessary to confirm the shape at the time of assembly. Becomes

[0009]

As described above, according to the present invention, the airtightness can be maintained when the shaft is mounted, and the tail plug alone can have a sufficient air flow passage.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a use state.

FIG. 2 is a view taken in the direction of arrow I in FIG. 1 showing an example.

FIG. 3 is an external view showing an example.

FIG. 4 is a diagram corresponding to FIG. 2, showing another example.

FIG. 5 is a view corresponding to FIG. 2, showing still another example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tail plug 2 Shaft cylinder 3 Liquid tight forming part 4 Display part 5 Annular belt convex part 6 Flange part 7 Liquid tight contact part 8 Convex part 9 Concave part 10 Protrusion 11 Hole

Claims (3)

[Claims] 1. A tail plug of a writing instrument, which is press-fitted into a rear end opening of a shaft cylinder containing ink therein, comprising a plurality of separable members, each member being a liquid for each member. It has a close contact portion and a liquid-tight pressure contact portion against the inner wall of the barrel, and in a state where the respective liquid-tight contact portions are in contact with each other, the outer periphery of the joined tail plug has a circumferential shape with respect to the inner wall of the barrel. When the members are separated from each other, a continuous ventilation portion formed of a concave portion and / or a convex portion extending in the longitudinal direction of the member is formed in the liquid-tight contact portion of each member. A tail plug of a writing instrument, characterized by being made. 2. The method according to claim 1, wherein the plurality of members of the tail plug include a member having a convex portion extending in a longitudinal direction at a liquid-tight contact portion of each member and a concave groove corresponding to the convex portion. The tail plug of the writing instrument according to claim 1. 3. The tail plug of a writing instrument according to claim 1, wherein the plurality of members of the tail plug have the same shape.