JP2001180172A - Tip for writing instrument and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a mass production to be precisely conducted by improving durability and a strength without existing a brittle part to a moment and smoothly supplying an ink. SOLUTION: The trip for a writing instrument comprises a small diameter part 4 having an inner diameter corresponding to the outer diameter of a ball 12 rotatably assembled at its tip end, a large diameter part 8 having an inner diameter larger than that of the part 4, a coupling part 6 for flexibly coupling the part 4 to the part 8 and made of a curved surface, and a reinforcing part 7 formed to project to its outside between the part 6 and the part 8. In this case, a predetermined plate material is deep drawn at many stages to integrally form the trip for the instrument.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of processing a sheet material by deep drawing so that rotation of a ball and circulation of ink are performed smoothly, durability is improved, and sufficient strength is obtained. TECHNICAL FIELD The present invention relates to a writing instrument tip including a connecting portion, a connecting portion formed on a smooth curved surface connecting the portions, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In general, a writing implement such as a ball-point pen has an ink storage tube in which ink is stored, a writing core composed of a tip assembled in the ink storage tube and having a ball rotatably assembled at a tip thereof, It is composed of an outer cylinder for protecting the writing core, and a cap assembled to the outer cylinder and in which a tip portion of the writing core is located.

A spring is provided inside the tip of the writing lead so as to always apply a force to the ball assembled at the tip toward the tip. The writing tip is divided into a cone tip formed in a cone shape and a needle tip formed in a thin pipe shape. The needle tip is very small because the inner diameter is formed to a size corresponding to the hole diameter. Therefore, when an external force such as bending is applied, the ink is easily damaged, the durability is low, the ink is not supplied smoothly, and the ink having a high viscosity is not easy to use.

Recently, the above problems have been solved.
A number of needle-shaped tips and methods for producing the same have been proposed in which the ink supply path can be freely designed to improve the durability without being limited to the ball diameter, and can be smoothly supplied even when the ink has a high viscosity.

One example of such a method of manufacturing a needle-type tip is to perform a multi-stage rotary swaging process on the tip of a thin metal pipe as described in Japanese Patent Application Laid-Open No. Hei 2-61341. Forming a small-diameter part, forming a hole for forming the ink guide core on the inner surface, forming a hole for the ball holding part and the ball receiving part, and forming a guide path for the ink guide core on the inner surface. Or a hole for forming a ball holding portion and a ball receiving portion, or a hole for forming a plurality of ink introduction grooves.

[0006] In the method of manufacturing a needle-type tip as described above, since a large number of cutting operations are performed, there may be cases where a burr, a cutting tip, or the like remains inside the ball holding portion. However, the inner surface roughness of the ball holding portion becomes coarse due to the wear of the cutting tool, which may hinder smooth rotation of the ball and smooth flow of ink. Then, since the ball holding portion is formed by cutting, the thickness of the circumferential wall is reduced and the strength is reduced. Therefore, when the ball is used for a long time, stable ball supportability cannot be maintained, and the ball is likely to fall off.

[0007] Further, when the axis of the pipe of the workpiece and the axis of the cutting tool cross each other during the cutting process, the thickness of the circumferential wall becomes uneven, the strength is reduced, and the dispersion of the inner diameter of the ball holding portion becomes large. In addition, there is a high possibility that the ball's supportability is reduced or the ball falls off.

Accordingly, in Japanese Patent Application Laid-Open No. Hei 10-193864, a large diameter portion having a straight cylindrical shape and a plurality of ball receiving protrusions are formed on a circumferential wall around the tip by firing deformation. The ball is rotatably held by the front surface of the projection, and the small-diameter portion of the straight cylindrical shape is connected to the large-diameter portion and the small-diameter portion.
Provided is a ballpoint pen tip comprising a tapered portion having an angle of 0 to 45 °. That is, the process is performed such that a small diameter portion, a tapered portion, and a large diameter portion are sequentially connected to a pair of stainless steel (e.g., austenitic stainless steel) pipes by firing.

In the ballpoint pen tip performed as described above, the small-diameter portion, the tapered portion, and the large-diameter portion are formed with a substantially uniform thickness as compared with the above-mentioned Japanese Patent Application Laid-Open No. 2-61341, so that an extremely thin portion is formed. Does not exist. Further, by forming the tapered portion at an angle of 10 to 45 °, since excessive deformation does not occur when performing firing deformation, it is possible to provide sufficient bending strength and always maintain a constant ink flow amount. it can.

[0010]

However, Japanese Patent Application Laid-Open Publication No.
The ballpoint pen tip described in Japanese Patent Publication No. 0-193864 has an outer diameter of about 2 mm, a long pipe is cut at a predetermined length, and this is fired and deformed to form a small diameter portion and a tapered portion. The handling of the pipe is difficult and there is a high risk of breakage or damage. In addition, since the small diameter portion and the tapered portion are connected at a predetermined angle, the portion becomes weaker when a moment acts than in other portions, and there is a possibility that bending occurs at this portion.

An object of the present invention is to solve the above-mentioned problems, and a small-diameter portion, a large-diameter portion, and a smooth portion are formed by deep drawing using a predetermined plate material at another stage. Since there is formed a connecting portion for connecting to a curved surface, there is no fragile portion in the moment, the durability and strength are improved, the ink supply is smooth, the chip for a writing implement which is precise and can be mass-produced, and a method of manufacturing the same. Is to provide.

[0012]

In order to achieve the above object, a writing instrument tip proposed by the present invention comprises a small-diameter portion formed at an inner diameter corresponding to an outer shape of a ball rotatably assembled at the tip, A large-diameter portion formed to have an inner diameter larger than the inner diameter of the small-diameter portion, and a connecting portion formed of a curved surface by smoothly connecting the small-diameter portion and the large-diameter portion, wherein the small-diameter portion, the large-diameter portion, and the connecting portion are The gist is that a predetermined plate material is integrally formed by multi-stage deep drawing.
Therefore, the small-diameter portion and the large-diameter portion and the connecting portion for smoothly connecting the small-diameter portion and the large-diameter portion to the curved surface are formed by deep drawing using a predetermined plate material, so that there is no portion that is vulnerable to moment, and durability and strength are improved. The improved ink supply will be smooth and precise and mass production will be possible. A reinforcing portion is formed between the connecting portion and the large diameter portion by bending the reinforcing portion so as to protrude outward. A plurality of holding projections for holding the ball are formed on the distal end portion of the small diameter portion so as to project from the inner peripheral surface by punching.

Further, the method for manufacturing a writing instrument tip proposed by the present invention is directed to a small-diameter portion having an inner diameter corresponding to the outer diameter of a ball rotatably assembled at the tip by deep drawing a predetermined plate material in multiple steps. And a piping step of forming a large-diameter portion having an inner diameter larger than the small-diameter portion and a connecting portion for smoothly connecting the small-diameter portion and the large-diameter portion to a curved surface, and holding a ball at a tip portion of the small-diameter portion. And a punching step of forming a plurality of holding projections to be held by punching so as to protrude from the inner peripheral surface. Therefore, the small-diameter portion and the large-diameter portion and the connecting portion for smoothly connecting the small-diameter portion and the large-diameter portion to the curved surface are formed by deep drawing using a predetermined plate material, so that there is no portion that is vulnerable to moment, and durability and strength are improved. The improved ink supply will be smooth and precise and mass production will be possible. In the above, between the piping step and the punching step, a bending step of forming a reinforcing part so as to protrude outward at a connecting part of the connecting part and the large diameter part may be further included.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a writing instrument chip and a method of manufacturing the same according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a writing instrument tip according to the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along the line II, and FIG. 3 is a cross-sectional view showing another embodiment of the writing instrument tip according to the present invention. First,
One embodiment of a writing instrument tip according to the present invention, as shown in FIG.
Small diameter part (4) formed on the inner diameter corresponding to the outer diameter of 2)
And a large-diameter portion (8) formed with an inner diameter larger than the inner diameter of the small-diameter portion (4), and the small-diameter portion (4) and the large-diameter portion (8) are connected flexibly (smoothly: smoothly). (6).

In the above, the small-diameter portion (4), the large-diameter portion (8) and the connecting portion (6) are formed integrally with a predetermined plate material by multi-step deep drawing. It is preferable that the deep drawing process is performed by using a transfer press performed continuously.

As shown in FIG. 1, the connecting portion (6) may be formed in a curved surface concaved inward, or may be formed in an inclined surface as shown in FIG. In the above, if the connecting portion (6) is formed into a curved surface that is depressed inward, since there is no corner portion, the bending strength against a moment is improved, and the connection portion (6) is not easily bent. Is done.

As shown in FIG. 1, a reinforcing portion (7) is formed between the connecting portion (6) and the large-diameter portion (8) by bending so as to protrude outward. The reinforcing portion (7) is formed by forming one substantially curved portion by bending. Further, the substantially curved portion of the reinforcing portion (7) is formed near the connection between the connecting portion (6) and the large diameter portion (8).
The above-described formation is closer to a shape in which the shape of the tip portion projects outward at an acute angle than the substantially curved shape. As shown in FIGS. 1 and 2, a plurality of holding projections (3) for holding the ball (12) are formed on the distal end portion of the small diameter portion (4) by punching. It is formed so as to protrude. It is preferable that three or four of the holding projections (3) are formed. After the ball (12) is inserted into the tip of the small diameter portion (4), the tip of the small diameter portion (4) is caulked.
g) By processing, it is rotatably assembled with the holding projection (3). It is preferable that the front end portion (9) of the rear end of the large diameter portion (8) is bent inward so as to be easily assembled.

One embodiment of the method for manufacturing a writing instrument chip according to the present invention is, as shown in FIGS. 6 and 7, a predetermined plate material (1) is deep drawn in multiple steps and assembled rotatably at the tip. A small-diameter portion (4) formed with an inner diameter corresponding to the outer diameter of the ball (12) to be formed; a large-diameter portion (8) formed with an inner diameter larger than the small-diameter portion (4); and the small-diameter portion (4). A piping step (S1) for forming a connecting portion (6) for flexibly connecting the large-diameter portion (8), and a plurality of housings for holding the ball (12) at the tip of the small-diameter portion (4). A punching step (S3) of forming the holding projection (3) by punching so as to protrude from the inner peripheral surface. In one embodiment of the method for manufacturing a writing instrument chip according to the present invention, the connecting part (6) and the large diameter part (8) are connected between the piping step (S1) and the punching step (S3). Reinforcing part (7) to project outward
It is also possible to further include a bending step (S2) of forming

The piping step (S1) is performed such that a deep drawing is performed using a transfer press or the like. Initially, a predetermined plate (1) has a size larger than the inner diameter of the large diameter portion (8). At the same time as drawing process, gradually approaching the inner diameter of the large diameter part (8)
The multi-stage deep drawing is performed so that the connecting portion (6) and the small diameter portion (4) are formed. In the bending step (S2), a substantially curved reinforcing portion (7) is formed between the connecting portion (6) and the large diameter portion (8), and a front end portion of a rear end of the large diameter portion (8) is formed. (9) bending inward to facilitate assembly.

FIG. 4 shows a writing lead (10) to which the writing tool tip according to the present invention as described above is applied. The writing lead (10) rotates around a tip (2) composed of a small diameter part (4), a large diameter part (8) and a connecting part (6), and a tip part of the small diameter part (4) of the tip (2). A ball (12) that can be assembled and a chip holder (14) into which the large-diameter portion (8) of the chip (2) is inserted and supported.
A spring (16) inserted into the chip (2) and the chip holder (14) to apply a force to the ball (12) to the outside of the tip, and a spring (16);
4) is inserted and includes an ink storage tube (18) in which ink is stored.

FIG. 5 shows a ballpoint pen (20) to which the writing lead (10) configured as described above is applied. The ballpoint pen (20) includes a writing core (10), an outer cylinder (22) into which the writing core (10) is inserted, and a tip of the writing core (10) assembled to the outer cylinder (22). (24). The above-mentioned example shows an example in which the writing tool tip according to the present invention is applied to the general ballpoint pen (20). However, the present invention can also be applied to a knock-type ballpoint pen, and to other types of writing tools other than the ballpoint pen. It is also possible to apply.

A writing lead (10) and a ballpoint pen (2) to which the writing implement tip (2) according to the present invention as described above is applied.
In (0), since the large-diameter portion (8) is formed at an inner diameter larger than the small-diameter portion (4), the ink in the ink storage tube (18) passes through the large-diameter portion (8) and the connecting portion (6). 4)
Is smoothly supplied to the ball (12) assembled in the above.
The material of the ink storage tube (18) and the outer cylinder (22) is a synthetic resin (for example, polypropylene). In the above-described embodiments, the preferred embodiments of the writing instrument tip and the method of manufacturing the same according to the present invention have been described. However, the present invention is not limited thereto, and the claims and the detailed description of the present invention and the accompanying drawings are provided. Can be variously modified and implemented within the scope of the present invention, which also belongs to the scope of the present invention.

[0023]

As described above, according to the writing instrument tip and the method of manufacturing the same according to the present invention, the small-diameter portion and the large-diameter portion are connected by the connecting portion formed into a smooth curved surface. Since there is no portion where the load is concentrated when a moment is applied to the tip portion, no bending or the like occurs, and the durability is improved. Further, according to the writing instrument tip and the method of manufacturing the same according to the present invention, since the reinforcing portion is formed at the portion where the connecting portion and the large diameter portion are connected, the reinforcing portion is not easily deformed by external force, and the strength and durability are improved. You. And according to the method for manufacturing a writing instrument chip of the present invention,
Processing of plate material by continuous deep drawing such as transfer press to produce writing instrument chips, so precision processing and mass production are possible.Handling compared to manufacturing using conventional thin and long pipes And easy to manufacture.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a writing instrument tip according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a cross-sectional view showing another embodiment of the writing instrument tip according to the present invention.

FIG. 4 is a sectional view showing a writing lead to which another embodiment of the writing instrument tip according to the present invention is applied.

FIG. 5 is a cross-sectional view showing a ballpoint pen to which an embodiment of a writing instrument tip according to the present invention is applied.

FIG. 6 is a block diagram schematically showing one embodiment of a method for manufacturing a writing instrument chip according to the present invention.

FIG. 7 is a process diagram schematically showing one embodiment of a method for manufacturing a writing instrument chip according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Board material 2 Chip 3 Holding projection 4 Small diameter part 6 Connecting part 7 Reinforcement part 8 Large diameter part 10 Writing core 12 Ball 14 Tip holder 16 Spring 18 Ink storage tube 20 Ballpoint pen 22 Outer cylinder 24 Cap

Claims (6)

[Claims] 1. A small-diameter portion formed at an inner diameter corresponding to the outer shape of a ball rotatably assembled at a tip, a large-diameter portion formed at an inner diameter larger than the inner diameter of the small-diameter portion, and the small-diameter portion and a large diameter. And a connecting portion having a curved surface by smoothly connecting the portions with each other, wherein the small-diameter portion, the large-diameter portion and the connecting portion are integrally formed by a multi-stage deep drawing process of a predetermined plate material. Writing instrument tip. 2. The writing instrument tip according to claim 1, wherein a reinforcing portion is formed between the connecting portion and the large diameter portion by bending a reinforcing portion so as to protrude outward. 3. A plurality of holding projections for holding a ball are formed at a distal end portion of the small diameter portion so as to project to an inner peripheral surface by punching.
Or the writing instrument chip according to 2. 4. A small-diameter portion having an inner diameter corresponding to the outer diameter of a ball rotatably assembled at the tip by deep drawing a predetermined plate material in multiple stages, and a large-diameter portion having an inner diameter larger than the small-diameter portion. A piping step of forming a diameter portion and a connecting portion for smoothly connecting the small diameter portion and the large diameter portion to a curved surface; and a plurality of holding projections for holding a ball at a tip portion of the small diameter portion on an inner peripheral surface. A punching step of forming by punching so as to protrude from the writing tool. 5. The method according to claim 5, further comprising, between the piping step and the punching step, a bending step of forming a reinforcing portion so as to protrude outward at a connecting portion between the connecting portion and the large diameter portion. Item 5. The method for producing a writing instrument chip according to Item 4. 6. A chip comprising a small-diameter portion and a large-diameter portion integrally formed through a coupling portion formed of a curved surface, a ball rotatably assembled to a tip portion of the small-diameter portion of the chip, A tip holder into which a diameter part is inserted and supported; a spring inserted into the tip and the tip holder to apply a force to the outside of the tip of the ball; and a tip holder inserted therein, and ink stored therein. A ballpoint pen, comprising: a writing lead including an ink storage tube, an outer cylinder into which the writing lead is inserted, and a cap assembled to the outer pipe and in which the tip of the writing lead is located.