JPH08118877A - Tip part of ball-point pen - Google Patents

Abstract

PURPOSE: To give no unstable writing feel due to big shaking of a pipe in writing by a method wherein the proper axial length at the rear part of a pipe is forcedly fixed into a mounting hole through a supporting tube in a ball-point pen, in which the pipe with a ball held at its tip is fixed to the mounting hole of a holder. CONSTITUTION: A polyacetal resin supporting tube 4 has an outer diameter, which is slightly larger than the inner diameter of a mounting hole 31, and an inner hole 41, the diameter of which is slightly smaller than the outer diameter of a pipe 2. The proper axial length at the rear part of the pipe is forced in the mounting hole 31 provided at the tip of a brass holder 3 so as to project the fore part of the pipe 2 and the fore part of the supporting tube 4. Around the stainless steel pipe 2, a tip edge part 22 and a ball retaining seat 23, which are inwardly pressingly deformed, are formed so as to rotatably hold a hard metalball 21. Further, at the rear end of the pipe 2, an expanded part 24, which is deformed so as to expand in a tapered shape, is provided so as to contrive to surely abut the rear end of the pipe 2 against an engaging wall part 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen tip. More specifically, the present invention relates to a so-called pipe type ball-point pen tip portion in which a ball is rotatably held by the tip of a metal pipe and the pipe is fixed to a mounting hole of a holder.

[0002]

2. Description of the Related Art Conventionally, at the tip of this type of ball-point pen, for example, for the purpose of obtaining a soft writing feeling, the inner surface of a guide tube attached to the tip of the holder and the expanded portion at the rear end of the pipe are elastically fixed. The configuration that allows this is disclosed in Japanese Utility Model Publication No. 61-36381.

[0003]

However, in the above-mentioned conventional structure, since the pipe is held at one point at the rear end, the holding force is weak and the pipe has a soft writing feeling as it is used. There is a risk that the user will feel unstable when writing because it becomes wobbled beyond the limit of.

In particular, the pipe is thin such that the ball receiving seat is formed by inward deformation (specifically, the pipe has a wall thickness of 0.15 mm or less), or a small diameter for obtaining a pen tip for fine characters. (Specifically, the outer diameter of the pipe is 0.75
When the raw ink is directly circulated inside and the ink guiding member does not exist, the pipe itself is warped, which may increase the wobble. In addition, if the holder is made of synthetic resin, the fixing force between the holder and the pipe tends to be loosened due to changes over time, which is disadvantageous to wobble.

When the pipe has a relatively small diameter (specifically, the outer diameter of the pipe is 0.75 mm or less) or a thin wall (specifically, the wall thickness of the pipe is 0.15 mm or less), The contact area between the end and the contact portion of the holder mounting hole is reduced. Therefore, a shock such as a large writing pressure or a drop may deform or destroy the contact portion, or the rear end of the pipe may get over the contact portion, so that the pipe may sink into the holder. Particularly, the burial accident of the pipe is likely to occur when the holder is made of synthetic resin.

The present invention solves the above-mentioned problems of the prior art, and does not cause the pipe to wobble greatly during writing to give an unstable writing feeling, and there is no fear that the pipe will be buried in the holder. The aim is to provide an optimum ballpoint pen tip for fine print.

[0007]

According to the present invention, a ball 21 is rotatably held at the tip of a metal pipe 2 and the pipe 2 is fixed to a mounting hole 31 of a holder 3. 1, the support cylinder 4 is interposed between the inner circumference of the mounting hole 31 and the outer circumference of the pipe 2, and the rear portion of the pipe 2 has an appropriate length in the axial direction. It is required to be press-fitted and fixed inside 31.

Further, in the ball-point pen tip portion 1,
A tip edge portion 22 formed by inwardly deforming the tip of the pipe 2 and a ball receiving seat 23 formed by inwardly deforming the vicinity of the tip of the pipe 2 (specifically, a plurality of inward projecting portions) And a configuration in which the ball 21 is rotatably held, a configuration in which raw ink is directly passed through a hollow portion in the pipe 2, or an outer diameter of the pipe 2 is 0.75 m.
A configuration in which the thickness is set to m or less is preferable.

When the holder 3 is made of metal, the support cylinder 4 is preferably made of synthetic resin.
Further, when the holder 3 is made of synthetic resin, the support cylinder 4 is preferably made of metal. Examples of the metal material include brass, stainless steel, and aluminum, and examples of the synthetic resin material include polyacetal, polypropylene, polyethylene, and ABS resin.

At the tip portion 1 of the ballpoint pen, a pipe 2 projecting outward from the support cylinder 4 or the holder 3.
Is L (mm), and the outer diameter of the pipe 2 is D (m
m), L / D ≦ 4.0 (preferably L / D
It is preferable to satisfy the relationship of ≦ 3.5). When the wall thickness of the pipe 2 is T (mm), L / TD ²
It is preferable to satisfy the relationship of ≦ 80 (preferably L / TD ² ≦ 60). The "L / D" and "L / T"
“D ² ” represents the easiness of bending of the pipe 2, and the smaller the value, the more difficult the bending is and the safer it is. Particularly, when the above relationship is satisfied, sufficient bending is prevented, and even if the outer diameter D of the pipe 2 is a small diameter (0.75 mm or less), it is suitable for fine letters having sufficient strength against writing pressure. It is possible to obtain a simple pipe-type ball-point pen tip 1.

[0011]

Since the axially appropriate length portion of the rear portion of the pipe 2 is press-fitted and fixed in the mounting hole 31 via the support cylinder 4, the pipe 2 can be stably fixed, and the pipe 2 at the time of writing
Wobble is suppressed.

Further, the tip and the vicinity of the tip of the pipe 2 are pressed and deformed inward, so that the tip edge portion 22 and the ball receiving seat 2 are formed.
3 is formed, the raw ink is directly communicated with the hollow portion of the pipe 2, or the outer diameter D of the pipe 2 is 0.75 mm or less, the pipe through the support cylinder 4 By adopting the fixing structure of 2,
The wobble suppressing effect of the fixed structure of the pipe is effectively exhibited.

Since one of the holder 3 and the support cylinder 4 is made of metal and the other is made of synthetic resin, the pressure input when the support cylinder 4 is press-fitted into the mounting hole 31 of the holder 3 is reduced, and the assembling work is performed. It is possible to smoothen and firmly fix the holder 3 and the support cylinder 4 together. This is because when both are metal, excessive pressure input is required, and when both are synthetic resin, strong adhesion cannot be maintained.

In particular, when the holder 3 is made of metal, the abutting portion (specifically, the locking wall portion 32) that abuts the rear end of the pipe 2.
In addition to being more reliable in preventing the pipe 2 from being buried in the holder 3, the pipe 2 can be firmly fixed without being loosened due to aging or the like.

[0015]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. The metal pipe 2 is press-fitted into the inner hole 41 of the support cylinder 4 made of polyacetal resin. Then, an appropriate axial length of the rear portion of the support tube 4 is press-fitted into a mounting hole 31 provided at the tip of the brass holder 3, and the front portion of the pipe 2 and the front portion of the support tube 4 are exposed to the outside. It is protruding.

The mounting hole 31 has an inner diameter slightly smaller than the outer diameter of the support cylinder 4, and a locking wall portion 32 with which the rear end of the pipe 2 abuts is provided on the bottom portion. In addition, the locking wall portion 32
A communication hole 33 having substantially the same inner diameter as the inner diameter of the pipe 2 is provided therethrough. As a result, the locking wall portion 32 secures a sufficient contact portion with the rear end of the pipe 2 and at the same time, does not hinder the ink circulation.

The support cylinder 4 is a cylindrical body, and has an outer diameter slightly larger than the inner diameter of the mounting hole 31 of the holder 3 and the pipe 2.
An inner hole 41 having an inner diameter slightly smaller than the outer diameter is provided.

The pipe 2 is made of stainless steel. Further, at the tip of the pipe 2 and in the vicinity of the tip,
The tip edge portion 22 and the ball receiving seat 23 (specifically, three inward projecting portions) formed by being pressed and deformed inwardly hold the carbide ball 21 having an outer diameter of 0.3 mm so as to be rotatable. Has been done.

At the rear end of the pipe 2, there is provided an expanding portion 24 which is expanded and deformed into a taper shape.
A reliable contact between the rear end of the pipe 2 and the locking wall portion 32 is performed. Moreover, the expanding portion 24 can prevent the pipe 2 from coming off the support cylinder 4, and absorbs a large writing pressure (axial pressing force) on the pipe 2 due to its elastic force.

In this embodiment, the protruding length L of the pipe 2 (protruding length from the support cylinder 4) is 0.9 mm, and the outer diameter D of the pipe 2 is D.
Is set to 0.5 mm, the wall thickness T of the pipe 2 is set to 0.09 mm, and the relationship of L / D ≦ 3.5 and L / TD ² ≦ 60 is satisfied. Therefore, wobbling and bending of the pipe 2 during writing are sufficiently prevented.

FIG. 2 shows a second embodiment. A cylindrical support tube 4 made of polypropylene resin is press-fitted into the mounting hole 31 of the holder 3 made of brass, and a ball 21 is rotatably held at the tip of the same pipe as in the first embodiment. 2 is press-fitted into the inner hole 41 of the support cylinder 4. A communication hole 33 having an inner diameter substantially the same as the inner diameter of the pipe 2 penetrates through the locking wall portion 32 at the rear end of the mounting hole 31, and the rear end of the pipe 2 and the rear end of the support cylinder 4 are in contact with each other. In addition, the inner hole 41 of the support cylinder 4 has a length corresponding to the axial length of the rear portion of the pipe 2.
The pipe 2 is formed to have an inner diameter slightly smaller than the outer diameter so that the pipe 2 can be press-fitted, and a gap exists between the front portion and the outer periphery of the pipe 2. However, since the play size [(inner diameter of inner hole 41)-(outer diameter of pipe 2)] of the gap is about 0.01 mm to 0.1 mm, it has little influence on wobble during writing. Absent.

In this embodiment, the applied ball 21 has an outer diameter of 0.4 mm, the length L of the pipe 2 extending from the support cylinder 4 is 1.9 mm, and the outer diameter D of the pipe 2 is 0. 65m
m, the wall thickness T of the pipe 2 is 0.12 mm, and L / D ≦
3.5 and L / TD ² ≦ 60 are satisfied.

FIG. 3 shows a third embodiment. The pipe 2 has the same configuration as that of the first embodiment, and is press-fitted into the inner hole 41 of the support cylinder 4 and has its rear end abutting on the locking wall portion 42 provided at the rear end of the support cylinder 4. Further, the cylindrical support cylinder 4 made of polyethylene is press-fitted into the mounting hole 31 of the metal holder 3 similar to the first and second embodiments, and
The rear end is in contact with the locking wall portion 32 of the holder 3. Further, the locking wall portion 32 of the holder 3 and the support cylinder 4
Communication holes 33 and 43 having substantially the same inner diameter as the inner diameter of the pipe 2 are formed through the locking wall portion 42 of the above.

FIG. 4 shows a fourth embodiment. A mounting hole 31 is provided inside the holder 3 made of stainless steel, and a cylindrical support tube 4 made of polyacetal is provided in the mounting hole 31 from the rear side.
Is press-fitted and fixed. An inward projection 34 is provided at the rear end of the mounting hole 31. As a result, after the support cylinder 4 has passed over the inward projection 34 and is press-fitted into the mounting hole 31, the inward projection 34 prevents the rearward displacement of the support cylinder 4. The outer diameter and the inner diameter of the tip portion of the holder 3 are reduced, and the holder 3 is surrounded so as to have a slight gap (play size 0.01 mm to 0.1 mm) with the outer circumference of the pipe 2 as in the second embodiment.

The support cylinder 4 has a pipe 2 in its inner hole 41.
Is press-fitted and a locking wall portion 42 is provided at the rear end similarly to the third embodiment, and the rear end of the pipe 2 is brought into contact therewith. Further, as in the second embodiment, a communication hole 43 having an inner diameter substantially the same as the inner diameter of the pipe 2 is formed through the locking wall portion 42.
In addition, in this embodiment, the support cylinder 4 is embedded in the holder 3, and the protruding length L of the pipe 2 is measured from the tip of the holder 3.

FIG. 5 shows a fifth embodiment. At the tip of the holder 3 made of polyacetal resin, a mounting hole 31, a locking wall portion 32, and a communication hole 33 are provided as in the first embodiment. Similar to the first embodiment, the pipe 2 has a widened portion 24 at the rear end, and a stainless steel support cylinder 4 is attached to the outer periphery thereof. The rear portion of the pipe 2 is clamped and fixed by an inward pressing deformation portion 44 of the support cylinder 4. Then, an appropriate axial length of the rear portion of the support cylinder 4 to which the pipe 2 is clamped and fixed is press-fitted and fixed in the mounting hole 31 of the holder 3. Further, in this embodiment, the adhesive 45 is filled in the gap between the pressing deformation portion 44 and the mounting hole 31 to prevent ink leakage. In addition, the inner hole 41 of the support cylinder 4 and the pipe 2
And the play dimension is 0.01 mm, which is similar to the second embodiment.
A gap of about 0.1 mm is formed.

In the third, fourth and fifth embodiments,
The metal pipe 2 has the same structure as that of the first and second embodiments, and also has a protruding length L of the pipe 2, an outer diameter D of the pipe 2,
The wall thickness T of the pipe 2 is L / D ≦ 3.5, L / TD ² ≦ 6
The relationship of 0 is satisfied.

FIG. 6 shows an application example of the present invention. This is a ballpoint pen refill 5 in which the ballpoint pen tip 1 shown in the first to fifth embodiments is attached to the tip of an ink containing cylinder 6.

The ink container 6 is made of a transparent or translucent synthetic resin (polyethylene, polypropylene, etc.), and the ink 61 having a shear thinning property is provided therein.
(The viscosity at a shear rate of 384 sec ⁻¹ is 10 to 150 mPa · s at a temperature of 20 ° C.), and a backflow prevention plug 62 (for example, a grease-like backflow prevention agent) is stored at the rear end of the ink 61.

Besides this, although not shown, it is also effective to dispose an ink guiding member inside the pipe 2 as a means for supplying ink to the tip portion 1 of the ballpoint pen. Also,
The ball-point pen tip 1 of the present invention is, in addition to the above-mentioned application example, a so-called filling type ball-point pen in which an ink impregnated body impregnated with ink is provided in a barrel, an ink tank for directly storing raw ink, and a comb-like shape. With an ink holding member inside the barrel,
It can also be applied to a so-called direct liquid type ballpoint pen.

[0032]

As described above, the ball-point pen tip of the present invention has the above-mentioned structure, so that the wobbling of the pipe during writing can be suppressed and stable writing can be maintained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a third embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a vertical sectional view showing a fifth embodiment of the present invention.

FIG. 6 is a vertical sectional view showing an application example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ball-point pen tip part 2 Pipe 21 Ball 22 Tip edge part 23 Ball receiving seat 24 Expanding part 3 Holder 31 Mounting hole 32 Locking wall part 33 Communication hole 34 Inward projection 4 Support tube 41 Inner hole 42 Locking wall part 43 Communication hole 44 Pressing deformation part 45 Adhesive 5 Ball-point pen refill 6 Ink storage cylinder 61 Ink 62 Backflow prevention plug L Pipe extension length D Pipe outer diameter T Pipe wall thickness

Claims (6)

[Claims] 1. A ball (2) is attached to the tip of a metal pipe (2).
1) A tip portion of a ball-point pen, in which the pipe (2) is rotatably embraced and the pipe (2) is fixed to a mounting hole (31) of a holder (3), the inner periphery of the mounting hole (31) and the pipe. (2) The support cylinder (4) is interposed between the outer circumference and the support cylinder (4) so that the rear portion of the pipe (2) has an appropriate axial length.
A tip portion of a ball-point pen, which is press-fitted and fixed in the mounting hole (31) via the. 2. A tip edge portion (22) formed by inwardly deforming the tip of the pipe (2), and a ball receiving seat (22) formed by inwardly deforming the vicinity of the tip of the pipe (2). The ball-point pen tip according to claim 1, wherein the ball (21) is rotatably held by (23). 3. The ball-point pen tip according to claim 1, wherein the raw ink is directly circulated in the hollow portion of the pipe (2). 4. The ball-point pen tip according to claim 1, 2 or 3, wherein the outer diameter of the pipe (2) is 0.75 mm or less. 5. The holder (3) is made of metal, while the support tube (4) is made of synthetic resin.
The tip of the ball-point pen described in 2, 3, or 4. 6. The holder (3) is made of synthetic resin,
On the other hand, the support cylinder (4) is made of metal.
The tip of the ballpoint pen according to 3 or 4.