JPH0247031Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application) This invention relates to the tail plug of a writing instrument.
This invention relates to a tail plug for a writing instrument that reliably prevents ink from leaking from the tail plug side fitted to the rear part of a metal barrel having a batting impregnated with ink.

(Prior Art) Conventionally, writing instruments such as ballpoint pens and marking pens, or refills thereof (hereinafter referred to as writing instruments), have a filling impregnated with water-based ink.
Some of these writing instruments have barrels made of metal, but the tail plugs that fit into the rear of the metal barrels of these writing instruments are mainly made of resin, so they are resistant to temperature changes in the environment. Due to the different deformation rates due to contraction and expansion of the barrel and tail plug, a small gap is created between the barrel and the tail plug, and the capillary force of the gap causes ink to leak from the tail plug side. had.

Therefore, various methods are known in which several annular ribs are appropriately provided on the portion of the tail plug that is fitted to the rear inner wall surface of the shaft cylinder, and there are also attempts to achieve a tight fit by using adhesives. Since the rate of deformation of the barrel and tail plug differs due to temperature changes, it has not been possible to completely overcome ink leakage from the tail plug side.

(Problem to be solved by the invention) A type in which a metal tail plug is attached to the rear of the metal shaft cylinder is disclosed in Publication of Utility Model Publication No. 37-21915; Since the top surface of the bottom plate, which serves as a tail plug, is in complete contact with the entire lower end of the moisture absorbent material, it becomes difficult for air to circulate behind the moisture absorbent material, making it impossible to exchange air with the moisture absorbent material, resulting in a drop in ink. Another problem was that the discharge performance deteriorated.

(Means for solving the problem) This invention was created in view of the above circumstances.
In a metal tail plug of a writing instrument that is fitted to the rear inner wall surface of a metal barrel having a filling impregnated with ink, the tail plug is formed into a bottomed cylinder having a small diameter opening, and the tail plug is formed into a bottomed cylinder having a small diameter opening. By providing one or more recesses in the wall surface that communicate with the small diameter opening,
It is an object of the present invention to provide a tail plug for a writing instrument which eliminates ink leakage from the rear part of the barrel and allows air circulation at the rear part of the barrel without any hindrance.

(Function) Since the barrel and tail plug are made of metal,
The rate of deformation such as contraction and expansion in response to these temperature changes can be minimized, and since the recess provided on the wall of the tail plug communicates with the small diameter opening of the tail plug, this recess Air can flow smoothly through the barrel, especially to the batting.

(Example) Hereinafter, the present invention will be explained in detail based on an example.

1 and 2 show an embodiment of the present invention, and reference numeral 11 is a tail plug made of a metal such as stainless steel, nickel silver, or brass, and is a cylinder with a bottom. Smaller diameter opening 1 from approximately the middle part in the longitudinal direction
2, it has a tapered wall surface 13 that gradually becomes smaller in diameter toward the center, and this tapered wall surface 1
3, one or more (one in the figure) inwardly protruding recesses 14 that communicate with the small diameter opening 12.
are provided by press working or the like. The tail plug 11 is attached to the rear inner wall surface of a metal barrel 15 which has a filling 16 made of a fiber bundle of polyester, acrylic, etc. impregnated with ink, and the small diameter opening 12 is formed on the rear end surface of the filling 16. They are fitted so as to be in contact with each other, and furthermore, an annular gap S is formed between the inner wall surface of the shaft cylinder 15 and the tapered wall surface 13.

Therefore, since the tail plug 11 and the shaft cylinder 15 are made of metal fitting together, the rate of deformation due to environmental changes is as small as possible, or the rate of deformation is the same or close to each other, thereby preventing ink leakage. Shaft tube 15
The annular gap S and the recess 14 formed between the inner wall surface and the tapered wall surface 13 of the tail plug 11 allow good air exchange with the filling 16 inside the shaft cylinder 15. Furthermore, in the above embodiment, the recess 14 can serve as a locking means for preventing the batting 16 from moving backward. From this point of view, it is preferable that a plurality of recesses 14 be provided on the wall surface of the tail plug 11 at symmetrical positions.

In the above embodiment, the opening of the bottomed cylinder may be made into a small-diameter opening by providing an annular step without providing the tapered wall surface 13 on the tail plug 11, or the opening of the tail plug may be made into a small-diameter opening. By providing a plurality of inwardly protruding recesses in a circumferential manner that communicate with the
The opening of the bottomed cylindrical body may be made smaller in diameter to form a small-diameter opening.

(Effects of the invention) As described above, the present invention specifies the material and shape of the tail plug of a writing instrument, so it is possible to prevent ink from leaking from the tail plug side at the rear of the barrel, and to prevent air leakage inside the barrel. It has many advantages, such as smooth distribution and good ink ejection properties.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of the tail plug, and FIG. 2 is a longitudinal cross-sectional view of the main part of the tail plug shown in FIG. 1 when it is fitted into the shaft cylinder. 11...Tail plug, 12...Small diameter opening, 14...
Recessed portion, 15... shaft cylinder, 16... filling.

Claims (1)

[Scope of utility model registration request] In a metal tail plug of a writing instrument that is fitted to the rear inner wall surface of a metal barrel having a filling impregnated with ink, the tail plug is formed into a bottomed cylinder having a small diameter opening, and the tail plug is formed into a bottomed cylinder having a small diameter opening. A tail plug for a writing instrument, characterized in that one or more recesses are provided on a wall surface of the plug to communicate with the small-diameter opening.