JP2595848Y2 - Writing instrument cap mounting structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION A cap mounting structure for a writing instrument body having a temporary ink reservoir member disposed between an ink tank and a pen tip, wherein the pen tip is hermetically sealed between both the cap and the writing instrument body. The present invention relates to a press-fit contact portion formed by providing a circumferential projection on one side and a circumferential step on the other side.

[0002]

2. Description of the Related Art A writing instrument for storing ink in a raw ink state in an ink tank as described above is generally called a raw ink type writing instrument.

[0003] In this raw ink type writing instrument, a cap mounting structure for making the pen tip airtight is required in order to prevent ink from drying out from the pen tip. As an example, an annular elastic body is arranged on one of the writing instrument main body and the cap, and the contact portion provided on the other is brought into contact with the annular elastic body in an abutting manner,
There is a structure that shuts out the inside and outside air and makes the pen tip airtight.

[0004] As another example, there is a structure in which a circumferential press-fitting contact portion is formed between a cap and a main body to make the pen tip airtight.

[0005]

The above-described raw ink type writing implement has a problem that when the cap is attached, the volume of the space inside the cap changes in an airtight manner, which may cause ink leakage or ink drop. there were.

In the above-mentioned cap mounting structure, the cap and the annular elastic body provided on the writing instrument main body and the abutting portion are brought into contact with each other in an abutting manner. Since there is no large change, there is an advantage that ink leakage and ink bleeding hardly occur.

[0007] However, when the annular elastic body and the abutting portion are abutted against each other, a reaction to the abutting force results in a force that always removes the cap (hereinafter referred to as a cap removing force). ), Which is disadvantageous in view of the fitting force of the cap to the writing instrument main body.

On the other hand, in a structure in which a press-fitting contact portion is formed between the cap and the writing instrument main body to make the pen tip airtight, no cap removal force is applied when the cap is mounted, so that the fitting force is low. It is advantageous.

However, when the cap is attached, the press-fitting contact portion is
There is a problem that the volume change in the cap in the airtight state becomes relatively large, and ink leakage and ink drip easily occur. Hereinafter, the distance that the press-fitting contact portion moves in the airtight state when the cap is attached is simply referred to as a sliding distance.

The force for airtightness at the press-fitting contact portion is greatly related to the strength of the press-fit. However, if the press-fit is too large, both the writing instrument main body and the cap will be greatly deformed. As a result, the airtight state may not be maintained.

[0011]

That is, the present invention relates to a cap mounting structure for a writing instrument main body in which a temporary ink reservoir member is disposed between an ink tank and a pen tip. A press-fitting contact portion that seals the nib between the press-fitting contact portions, provided with a circumferential protrusion on one side and a circumferential step on the other side, wherein the circumferential protrusion is
Made of a material that is slightly harder than the circumferential step,
Tapered wall of the taper angle θ and standing before Symbol circumferential projection having
Chiage angle theta ₁ and has a relationship of θ _{1 <θ} (R is a straight
Angle), taper angles θ and θ ₁ are 135 degrees ≦ θ ≦ 160
Every time, the writing instrument, which is a theta _1> R Cap
The mounting structure is the gist.

[0012]

In the raw ink type writing instrument, it is preferable that the slide distance is short. This sliding distance can be divided into a stage where a cap removing force is applied and a stage where the force is substantially not applied when the process of moving the contact portion when the cap is attached is viewed.

The stage in which the cap removal force is applied is actually
The press-fitting contact portion is a contact portion between the tapered wall of the circumferential step and the circumferential projection. The stage where the cap removing force is not applied is a portion beyond the circumferential step. It can be said that the smaller the taper angle θ of the tapered wall, the closer the contact portion at the stage where the cap removing force is applied becomes closer to the top wall of the circumferential step portion. Therefore, the sliding distance becomes shorter, and θ is substantially 160 degrees or less.
If the angle is 135 degrees or less, the cap removing force will greatly act on the press-fitting, which is not preferable.

Further, the circumferential projection is made of a relatively soft material,
When the circumferential step is made of a relatively hard material,
Assuming that the whole is largely elastically deformed, the force for sealing the press-fitting contact portion is weak. However, in the structure of the present invention, the circumferential projection is made of a relatively hard material, and the circumferential step is made of a relatively soft material. If input
The force to make the press-fitting contact portion airtight increases.

[0015]

FIG. 1 shows an example. Reference numeral 1 denotes a writing instrument main body made of a resin such as polyethylene. The writing instrument body 1 has a pen tip 2 made of a porous material such as urethane at the tip. The pen tip 2 communicates with the ink tank 6 at an ink core 5 passing through an inner hole 4 of a temporary ink reservoir member 3 having a comb-shaped vertical cross section. The temporary ink reservoir member 3 has an air flow hole 9 at a front end 7 fixed to a shaft 8 of the writing instrument main body 1 and further holds the pen tip 2 therebetween.

Reference numeral 10 denotes a cap made of a resin such as polypropylene, which has a fitting portion 11 for the writing implement main body 1 and a circumferential press-fitting contact portion I for the writing implement main body 1.

FIG. 2 is an enlarged schematic diagram illustrating the press-fitting contact portion I in FIG. Reference numeral 12 represents a protrusion,
Reference numeral 13 represents a step.

When the cap is attached, the projection 12 and the step 13 start to press-fit against each other at a point A, and when the cap is further advanced, the projection 12 and the step 13 pass through the point B to reach the point C. Here, between points AB
At the stage where the cap removing force is applied, the space between points BC is the stage where the cap removing force is not applied.

Here, a straight line L passing through the point A and being parallel to a straight line connecting the points B and C is considered. Assuming that a straight line passing through the point C perpendicular to the straight line L is M, and an intersection of the straight line L and the straight line M is D, the slide distance is a length of a line segment connecting the point A and the point D.

When the taper angle θ of the step portion 13 is large, the taper wall becomes a straight line passing through the points A ₀ and B, and the sliding distance between the points A ₀ and D is determined. Because it will be length,
It will be long.

Here, in order for the tip 14 of the projection 12 to abut against the tapered wall 15 of the step so as not to apply a large fitting force, the rising angle θ ₁ of the projection 12 must be θ ₁
<Θ , and θ ₁ > (2R−θ) must be satisfied (R is a right angle). Also, the taper of the tapered wall 15
-The angle θ is 135 degrees ≦ θ ≦ 160 degrees, and
Considering that it is an injection molded product, it is not θ ₁ > R
Not be.

FIG. 3 is an enlarged view of a portion I in FIG.
The difference from the schematic diagram of FIG. 1 is that the tip 14 and the step 13 of the circumferential projection 12 are formed in a gentle shape considering the actual thing. As in FIG. 2, when the cap is attached, the circumferential projection 12 comes into contact with the tapered wall portion 15 of the step portion 13 (point A), and when the point B is reached, the cap removing force is not applied. At this point, the mounting of the cap ends.

Here, the taper angle θ is defined as a point A and a point B.
And a straight line passing through the points B and C.
Here, a raw ink type writing pen is shown as an example of the raw ink type writing implement, but other examples include a ball pen, a small tube type writing implement, a resin pen tip writing implement, a fountain pen, and a cosmetic.

[0024]

As described above, the writing implement of the present invention makes it difficult to cause ink leakage or ink drip due to the volume change of the space inside the cap in an airtight state when the cap is attached, and it is possible to reduce the pressure with a small pressure input. It is a cap mounting structure for a writing instrument that can reliably maintain airtightness in the cap.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the present invention.

FIG. 2 is an enlarged schematic diagram illustrating a portion I in FIG.

FIG. 3 is an enlarged view of a portion I in FIG.

[Explanation of symbols]

 I Press-In Contact Part 1 Writing Tool Main Body 2 Pen Tip 3 Temporary Ink Reservoir Member 4 Inner Hole 5 Ink Lead 6 Ink Tank 7 Front End 8 Shaft 9 Air Flow Hole 10 Cap 11 Fitting Part 12 Protrusion 13 Step 14 Tip 15 Taper wall

Claims (1)

(57) [Scope of request for utility model registration] 1. A cap mounting structure for a writing instrument main body in which a temporary ink reservoir member is disposed between an ink tank and a pen tip, wherein the pen tip is press-fitted between both the cap and the writing instrument main body. In the case where the contact portion is formed by providing a circumferential projection on one side and providing a circumferential step on the other side,
The circumferential protrusion is made of a material that is slightly harder than the circumferential step portion.
And the taper angle of the tapered wall of the peripheral step portion
θ and the rising angle θ ₁ of the circumferential projection are related by θ ₁ <θ.
(R is a right angle), and the taper angles θ and θ ₁ are 13
5 degrees ≦ θ ≦ 160 degrees, and θ ₁ > R
Writing instrument cap mounting structure.