JP3139355U - Pipe ballpoint pen tip - Google Patents

Abstract

Provided is a pipe-type ballpoint pen tip that can be punched properly in spite of a very small ball and that can sufficiently suppress wear of a ball receiving seat.
A tapered edge portion 3 having a tapered surface 31 on the outer surface is formed at the tip of a thin metal tube 2. A plurality of inward protruding portions 4 for ball receiving seats are formed by punching on a straight cylindrical side wall behind the edge portion 3 of the thin tube. The crimped portion 5 is formed by bending the tip of the edge portion 3 of the narrow tube 2 inwardly on the inner surface in the vicinity of the tip of the thin tube 2. The ball 6 is rotatably held by the ball receiving seat and the crimping portion 5. When the outer diameter of the ball 6 is A, the diameter of a virtual inscribed circle in contact with the apex of the inward projecting portion 4 is B, and the thickness of the thin tube is T, “0.15 mm ≦ A ≦ 0.29 mm”, “1 .8 ≦ A / T ≦ 3.5 ”and“ 0.5 ≦ B / T ≦ 1.5 ”are satisfied.
[Selection] Figure 1

Description

The present invention relates to a pipe-type ballpoint pen tip. In detail, it is related with the pipe-type ball-point pen tip provided with the micro ball.

Conventionally, in this type of pipe-type ballpoint pen tip, Patent Document 1 discloses a plurality of inward protruding portions for a ball receiving seat formed by pressing and deforming the vicinity of the tip of a metal pipe inward, and the tip of the pipe. A ballpoint pen tip having a ball rotatably held at the tip by a tip edge formed by pressing and deforming the ball inwardly, wherein the ball has an outer diameter A and a virtual contact with the apex of the inward projection. When the diameter of the inscribed circle is B and the thickness of the pipe is T,
A is in the range of 0.25 mm to 0.55 mm,
2.5 ≦ A / T ≦ 4.5,
and,
0.5 ≦ B / T ≦ 2.0
It is described that the relationship is satisfied.
JP-A-8-11476

In the conventional pipe-type ballpoint pen tip, when the ball is a very small ball having an outer diameter of less than 0.3 mm, if the thickness T of the pipe is excessively increased, the pipe protrudes inward due to inward pressing deformation (that is, punching). When forming the portion, the tip of the punch comes into contact with the taper surface of the tapered edge portion, and the tip of the punch slides along the taper surface to perform an appropriate punching process (that is, an appropriate inward protruding portion). Cannot be formed).

Furthermore, in the case of a conventional pipe-type ballpoint pen tip, when the ball is an extremely small ball having an outer diameter of less than 0.3 mm, the wear of the ball seat due to the rotation of the ball is severe, and the writing feeling decreases in a short period from the start of writing. , There is a risk that writing becomes impossible.

The present invention solves the above-mentioned conventional problems, and despite being equipped with a very small ball, it can properly punch and prevent bending of a thin tube, and further, An object of the present invention is to provide a pipe-type ballpoint pen tip having a ball receiving seat that can sufficiently suppress wear and can supply a sufficient amount of ink.

The present invention is characterized by the following requirements.

(Claim 1)
A tapered edge portion having a tapered surface on the outer surface is formed at the tip of the metal thin tube, and the outer surface of the straight cylindrical side wall behind the edge portion of the thin tube is pressed and deformed inward by punching. A plurality of inward protruding portions for ball receiving seats are formed on the inner surface in the vicinity of the distal end of the thin tube, the ball is accommodated on the front side of the inner protruding portion, and the distal end of the edge portion of the thin tube is formed inwardly in a circular shape. A pipe-type ballpoint pen tip which is formed by bending a pin into a crimped portion and holding the ball rotatably by the ball receiving seat and the crimped portion;
When the outer diameter of the ball is A, the diameter of a virtual inscribed circle in contact with the apex of the inward protruding portion is B, and the wall thickness of the thin tube is T,
0.15 mm ≦ A ≦ 0.29 mm,
1.8 ≦ A / T ≦ 3.5,
And 0.5 ≦ B / T ≦ 1.5
A pipe-type ballpoint pen tip that satisfies the above-mentioned relationship.

(Claim 2)
The pipe-type ballpoint pen tip according to claim 1, wherein an axial distance L from the rear end of the tapered surface of the edge portion to the center of the inward protruding portion is set to 0.03 mm or more.

According to claim 1, it is possible to avoid the contact of the tip of the punch with the tapered surface of the edge portion despite the provision of the small ball, to perform an appropriate punching process, and to sufficiently bend the narrow tube at the time of writing. Can be prevented. Further, according to the first aspect, it is possible to form an appropriate ball receiving seat capable of suppressing the wear of the ball receiving seat and capable of supplying a sufficient amount of ink despite the provision of the minimum ball.

According to the second aspect, it is possible to sufficiently avoid the punch tip from coming into contact with the tapered surface of the edge portion, and it is possible to more appropriately perform an appropriate punching operation on the outer surface of the straight cylindrical side wall of the thin tube.

The best mode for carrying out the present invention will be described.

[1] In the best mode of the present invention, a tapered edge portion 3 having a tapered surface 31 on the outer surface is formed at the tip of a metal thin tube 2, and a right cylindrical shape behind the edge portion 3 of the thin tube 2. The outer surface of the side wall of the thin tube 2 is pressed and deformed inward by punching, and a plurality of inward protruding portions 4 for ball receiving seats are formed on the inner surface in the vicinity of the tip of the thin tube 2 by the pressing deformation. A ball 6 is accommodated on the front side, and a crimping portion 5 is formed by bending the tip of the edge portion 3 of the narrow tube 2 inwardly in a circumferential shape, and the ball 6 is formed by the ball receiving seat and the crimping portion 5. A pipe-type ballpoint pen tip that is held in a rotatable manner,
When the outer diameter of the ball 6 is A, the diameter of a virtual inscribed circle in contact with the apex of the inward projecting portion 4 is B, and the thickness of the thin tube 2 is T,
0.15 mm ≦ A ≦ 0.29 mm,
1.8 ≦ A / T ≦ 3.5,
And 0.5 ≦ B / T ≦ 1.5
It is a requirement to satisfy the relationship (Claim 1).

The pipe-type ballpoint pen tip 1 (Claim 1) is provided with a very small ball 6 (a ball having an outer diameter of 0.15 mm to 0.29 mm, preferably a ball having an outer diameter of 0.20 mm to 0.29 mm). First, by satisfying the relationship of “1.8 ≦ A / T ≦ 3.5”, the outer surface of the straight cylindrical wall near the tip of the thin tube 2 can be appropriately punched, and the thin tube 2 The sufficient thickness can sufficiently prevent the thin tube 2 from being bent during writing, and a sufficient strength of the thin tube 2 can be obtained.

Further, the pipe-type ballpoint pen tip 1 (Claim 1) is provided with an extremely small ball 6 (a ball having an outer diameter of 0.15 mm to 0.29 mm, preferably a ball having an outer diameter of 0.20 mm to 0.29 mm). Nevertheless, by satisfying the relationship of “0.5 ≦ B / T ≦ 1.5”, it is possible to sufficiently suppress wear of the ball receiving seat and to provide a ball receiving seat capable of supplying sufficient ink. Can be formed.

In the present invention, the thickness T of the thin tube 2 refers to the thickness of the straight cylindrical portion of the thin tube 2 that is not punched.

[2] In the pipe-type ballpoint pen tip 1 (Claim 1), the axial distance L from the rear end of the tapered surface 31 of the edge portion 3 to the center of the inward protruding portion 4 is set to 0.03 mm or more. (Claim 2) is preferable.

The pipe-type ballpoint pen tip 1 (Claim 2) has no risk of the punch tip coming into contact with the taper surface 31 of the edge portion 3 even if manufacturing variations occur, and the pipe-type ball pen tip 1 is surely attached to the outer surface of the right cylindrical wall near the tip of the thin tube 2. Can be punched. If the axial distance L from the rear end of the tapered surface 31 of the edge portion 3 to the center of the inward protruding portion 4 is less than 0.03 mm, the tip of the punch is the tapered surface of the edge portion 3 depending on manufacturing variations. There is a possibility that the proper inward protruding portion 4 (ball receiving seat) cannot be formed in contact with 31. The axial distance L from the rear end of the tapered surface 31 of the edge portion 3 to the center of the inward projecting portion 4 is that a more appropriate inward projecting portion 4 (ball seat) can be formed. 0.05 mm or more (preferably in the range of 0.05 mm to 0.20 mm) is effective.

FIG. 1 shows a pipe-type ballpoint pen tip 1 according to an embodiment of the present invention. The pipe-type ballpoint pen tip 1 of the present embodiment includes a straight cylindrical metal thin tube 2 made of stainless steel (for example, austenitic stainless steel such as SUS321), and an inner surface near the tip of the thin tube 2 and deformed inwardly. (I.e., punching process) formed by a plurality of (here, three) inwardly projecting portions 4 and a tip of the tapered edge portion 3 of the tip of the thin tube 2 are arranged inwardly in a circle. It consists of a crimping portion 5 formed by deforming, and a ball 6 that is rotatably held between the inward protruding portion 4 (ball receiving seat) and the crimping portion 5.

A tapered edge portion 3 having a tapered surface 31 (conical surface) on the outer surface is formed at the distal end portion of the thin tube 2. The thin tube 2 is formed in a straight cylindrical shape having a substantially constant outer diameter from the rear end of the tapered edge portion 3 to the rear end of the thin tube 2 and has a needle shape. In the present invention, the right cylindrical portion of the narrow tube 2 is formed from the rear end of the tapered edge portion 3 to at least the place where the punch tip abuts (that is, the center of the inward projecting portion 3). That's fine.

In this embodiment, the ball 6 has an outer diameter A of 0.25 mm. The wall thickness T of the narrow tube 2 is set to 0.09 mm. A diameter B of a virtual inscribed circle in contact with the apex of the inward projecting portion 4 is set to 0.08 mm. An axial distance L from the rear end of the tapered surface 31 of the edge portion 3 to the center of the inward protruding portion 4 is set to 0.11 mm. Therefore, the value of A / T is 2.78, and the value of B / T is 0.89.

(Application example)
FIG. 2 shows an application example of the embodiment (FIG. 1) (that is, a ballpoint pen 7 to which the pipe-type ballpoint pen tip 1 of the embodiment is applied). The ballpoint pen 7 includes a shaft cylinder 8 and a ballpoint pen refill 9 accommodated in the shaft cylinder 8.

The shaft cylinder 8 includes a metal front shaft 81, a synthetic resin rear shaft 82, and a synthetic resin tail plug 83.

The tip shaft 81 is obtained by cutting a metal material (for example, brass). The distal end portion of the tip shaft 81 has an outer peripheral surface that is tapered by cutting. Further, a straight tip hole is formed through the tip of the tip shaft 81 by cutting, and a tapered inner surface is formed by cutting on the inner surface of the tip shaft 81 behind the tip hole. Furthermore, an internal thread portion is formed on the inner surface of the front shaft 81 behind the tapered inner surface by cutting.

The rear shaft 82 is obtained by injection molding of synthetic resin. A male screw portion is formed on the outer peripheral surface of the front end portion of the rear shaft 82, and the male screw portion and the female screw portion of the front shaft 81 are detachably screwed together. A tail plug 83 is press-fitted and fixed to the rear end opening of the rear shaft 82.

The ball-point pen refill 9 includes the pipe-type ball-point pen tip 1 of FIG. 1, a synthetic resin holder 92 to which the pipe-type ball-point pen tip 1 is fixed at the tip, and a pipe-type that is fixed to the tip of the holder 92. A support cylinder 93 that supports the outer peripheral surface of the ball-point pen tip 1 and an ink storage tube 91 having the holder 92 fixed to the front end opening and the rear end opened.

The ink containing tube 91 is obtained by extrusion molding of a synthetic resin (for example, polypropylene). An ink 91a (for example, a water-based gel ink) and a follower 91b (for example, a high-viscosity fluid) that is disposed at the rear end of the ink 91a and moves forward as the ink 91a is consumed are disposed inside the ink storage tube 91. Filled.

The holder 92 is obtained by injection molding of a synthetic resin (for example, polypropylene). The holder 92 is provided continuously with a cylindrical front portion to which the pipe-type ballpoint pen tip 1 is press-fitted and fixed, and a rear end of the cylindrical front portion, and also includes a front end surface of the ink containing tube 91, a front end surface of the rear shaft 82, And a flange that can contact the tapered inner surface of the front shaft 81, and a cylindrical rear portion that is connected to the rear of the flange and that is press-fitted and fixed to the tip opening of the ink containing tube 91 are integrally formed. Is done.

A metal support cylinder 93 is fixed to the outer peripheral surface of the cylindrical front portion of the holder 92. The support cylinder 93 supports the outer peripheral surface behind the tip of the pipe-type ballpoint pen tip 1 to prevent the pipe-type ballpoint pen tip 1 from wobbling during writing.

(Test results)
Table 1 shows the results of investigating punch workability and bending strength by preparing nine types of samples having different combinations of the ball 6 having an outer diameter A of 0.25 mm and the thickness T of the thin tube 2.

(Punch workability)
In the evaluation of the punch workability test, “○” indicates that the outer peripheral surface of the straight cylindrical side wall of the thin tube 2 can be reliably punched, and the punch tip abuts against the tapered surface 31 of the edge portion 3. Those that could not be punched properly were marked with “x”.

(Bending strength)
In the bending strength test, the sample was applied to the ballpoint pen shown in FIG. 2 and confirmed by handwriting by three inspectors. The evaluation of the result of this test is “○” when there is no bending of the thin tube 2 and wobbling of the thin tube 2 in normal writing, and there is no wobbling of the thin tube 2 in normal writing, but worries about wobbling. “△”.

Table 2 shows six samples of different combinations of a ball 6 having an outer diameter A of 0.25 mm and a diameter B of a virtual inscribed circle in contact with the apex of the inward projecting portion 4, and these are shown in FIG. This shows the results of investigations on ball seat wear and ink spillability when applied to ballpoint pens.

(Ball seat wear)
The ball seat wear test was conducted by using a ballpoint pen shown in FIG. 2 and filling 0.4 g of water-based gel ink into the ink containing tube 91 and writing tester (writing angle 70 degrees, writing load 100 g, writing speed 4 m. After 700 m writing, the amount of increase in the ball's axially movable amount was measured, and the writing feeling was confirmed by handwriting by three inspectors. The result of this test was evaluated as “◯” when the wear of the ball seat was less than 10 μm and no deterioration in writing feeling was observed, the wear of the ball seat was 10 μm or more, and the writing feeling was slightly Those that had decreased to “△”.

(Ink spillability)
In the ink efflux test, the sample was confirmed by handwriting by three inspectors. In the evaluation of the test results, “◯” indicates that there was no handwriting blur and smooth ink outflow property was obtained, and “x” indicates that the handwriting blur occurred.

(A) is the principal part expansion longitudinal cross-sectional view of the pipe-type ball-point pen tip of this invention, (b) is XX sectional drawing of (a). It is a longitudinal cross-sectional view which shows the ball-point pen which employ | adopted the pipe-type ball-point pen tip of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe type ball-point pen tip 2 Narrow tube 3 Edge part 31 Tapered surface 4 Inward protrusion part (ball receiving seat)
5 Caulking portion 6 Ball 7 Ball pen 8 Shaft tube 81 Lead shaft 82 Rear shaft 83 Tail plug 9 Ball pen refill 91 Ink receiving tube 91a Ink 91b Follower 92 Holder 93 Support tube A Ball outer diameter B Contact the top of the inward projecting portion Diameter of virtual inscribed circle T Thickness of thin tube L Axial distance from rear end of tapered surface of edge part to center of inward protruding part

Claims (2)

A tapered edge portion having a tapered surface on the outer surface is formed at the tip of the metal thin tube, and the outer surface of the straight cylindrical side wall behind the edge portion of the thin tube is pressed and deformed inward by punching. A plurality of inward protruding portions for ball receiving seats are formed on the inner surface in the vicinity of the distal end of the thin tube, the ball is accommodated on the front side of the inner protruding portion, and the distal end of the edge portion of the thin tube is formed inwardly in a circular shape. A pipe-type ballpoint pen tip which is formed by bending a pin into a crimped portion and holding the ball rotatably by the ball receiving seat and the crimped portion;
When the outer diameter of the ball is A, the diameter of a virtual inscribed circle in contact with the apex of the inward protruding portion is B, and the wall thickness of the thin tube is T,
0.15 mm ≦ A ≦ 0.29 mm,
1.8 ≦ A / T ≦ 3.5,
And 0.5 ≦ B / T ≦ 1.5
A pipe-type ballpoint pen tip that satisfies the above-mentioned relationship.   The pipe-type ballpoint pen tip according to claim 1, wherein an axial distance L from the rear end of the tapered surface of the edge portion to the center of the inward protruding portion is set to 0.03 mm or more.

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