JPH11165485A - Manufacture of ball-point pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tip of which the tip end surface is uniform and sharp, and of which the writing feeling is favorable by a method wherein a core pin is inserted in the tip end of a metal tube, and the total periphery of the external surface of the tip end is press-deformed into a tapered shape, and at the same time, a tapering-in is performed, and then, a ball-embracing hole is formed by a drill of a most suitable diameter. SOLUTION: A core pin 2 which is rotatably held is inserted in a metal fine tube 1 comprising a stainless steel fine tube, and two rolls are revolved with the core pin 2 as the center while rotating the rolls 5, and a tapering-in process wherein the tip end is press-deformed into a tapered-shape is applied extending to the total periphery of the external surface of the tip end. By this tapering-in process, a rounded part 3 is formed on the tip end. Then, a ball- embracing hole is formed at the tip end by using a drill, and then, the vicinity of the tip end of the metal fine tube 1 is press-formed inward at a plurality of locations, and an inward protruding part 8 as a ball receiving seat is formed. After fitting a ball in the ball receiving seat, a tip end mouth edge 10 is caulked inward, and the ball is embraced, and a required ball-point pen tip is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ballpoint pen tip from a thin metal tube.

[0002]

2. Description of the Related Art As a conventional method of manufacturing a ball-point pen tip from a metal tube, a ball receiving seat is formed by cutting the vicinity of the tip of the metal tube into a tapered shape, and then pressing and deforming a plurality of portions inward to form an inwardly projecting portion. After inserting the ink guide core having capillary action from the rear end by a plurality of slits in the axial direction from the rear end to form a receiving seat, after mounting a ball there, caulking the edge of the front end inward to produce a chip There is a way.

[0003] Further, with a core rod inserted into the metal thin tube, a concave cutting groove is formed on the surface of the metal thin tube by plastic deformation while rolling the metal thin tube by orthogonally pressing a cutting tool having a convex portion against the metal thin tube. A method is also known in which a receiving seat is formed in the same manner as described above, a ball is mounted thereon, and a tip end edge is caulked inward after the ball is mounted thereon.

[0004]

When the vicinity of the tip of a thin metal tube is cut into a tapered shape by the conventional processing method, the tip cannot be made sharp and the tip hits the paper surface during writing, resulting in a poor writing feel. There were drawbacks.

[0005] Further, when the cutting tool having the convex portion is pressed perpendicularly to the metal thin tube and cut while forming a concave groove due to plastic deformation on the surface of the metal thin tube, the cut surface is difficult to be uniform, and a film-like burr is not formed. There is a drawback that is likely to occur.

[0006]

According to the ballpoint pen tip of the present invention devised to achieve the above object, a core pin rotatably held at the tip of a metal pipe is inserted from the rear end side, and the tip of the core pin is inserted. Press and deform in a taper shape over the entire outer surface of the part and taper the tip end surface to be perpendicular to the pipe side surface, then form a ball holding hole with an optimal diameter drill to make the tip end surface uniform and sharp The task is to create a good writing tip.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows SUS304 and SUS3 in the thin metal tube 1.
05, SUS316, SUS430, etc., made of thin stainless steel tube, and the outer diameter is 1.5 to 2.4 of the ball diameter
The inner diameter is preferably 1 to 1.1 times the ball diameter, and the hardness is preferably 140 to 300 in Vickers hardness.

Next, as shown in FIG. 2, a core pin 2 rotatably held at the distal end of the thin metal tube 1 is inserted from the rear end side, and is pressed and deformed in a tapered shape over the entire outer surface of the distal end. Is tapered until it is perpendicular to the side surface of the thin metal tube. Here, a tip R portion 3 is formed at the tip portion that has been tapered. The size of the tip R portion formed at the tip portion is desirably from R0.05 mm to R0.1 mm. Also, in the pre-constriction processing, the amount of deformation of the material varies, but this varies in a direction perpendicular to the side surface of the thin metal tube,
The tip surface 4 in the axial direction of the thin metal tube is uniform and dimensionally stable.
Here, as a method of pressing in a taper shape over the entire outer surface of the thin metal tube 1, the two rolls 5 are revolved around the core pin 2 while rotating, and the orbital radius is gradually reduced, and the tip R portion 3 and the tip surface 4 are gradually reduced. Is formed, or the two rolls 5 are revolved around the core pin 2 while rotating, and the revolving radius is fixed at a predetermined position, and is pressed down from above the thin metal tube 1 to a predetermined position in the axial direction. A method of processing, and further, a method such as swaging or pressing with a die are conceivable.

In the next step, a ball holding hole 7 is formed by a drill 6 as shown in FIG. The diameter of the ball holding hole 7 is preferably 1.01 to 1.10 times the ball diameter.

Further, in the next step, the first embodiment, as shown in FIG. 4, the vicinity of the tip of the thin metal tube is pressed and deformed inward at a plurality of places to form an inwardly projecting portion 8 to form a ball receiving seat, and the ball 9 is mounted thereon. Thereafter, as shown in FIG. 6, the tip edge 10 is swaged inward to hold the ball 9 and form a ballpoint pen tip.

In the second embodiment, as shown in FIG. 3, after the ball holding hole 7 is formed by the drill 6, the ink guide core 11 having a capillary action is inserted from the rear end by a plurality of slits in the axial direction to form a receiving seat. After the ball 9 is mounted thereon, FIG.
The tip edge 10 is swaged inward to hold the ball 9 to form a ballpoint pen tip.

As described above, in the ball-point pen tip processing method of the present invention, the tip edge is rounded and sharp, so that the ball-point pen can obtain a smooth writing feeling without being caught on the paper when writing. Chips can be formed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a metal tube before processing according to the present invention.

FIG. 2 is a diagram showing one method of forming a tapered surface and a tip R portion by using a core pin and a rotating roll.

FIG. 3 is a view showing a method of forming a ball holding hole by a drill.

FIG. 4 is a longitudinal sectional view showing a ball receiving seat formed with an inwardly protruding portion.

FIG. 5 is a vertical sectional view taken along line AA of FIG. 4;

FIG. 6 is a longitudinal sectional view showing a method of caulking a ball in Example 1.

FIG. 7 is a longitudinal sectional view showing a method for caulking a ball according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal thin tube 2 Core pin 3 Tip R part 4 Tip face 5 Roll 6 Drill 7 Ball holding hole 8 Inward projection 9 Ball 10 Tip rim 11 Ink guide core

Claims (2)

[Claims] 1. A core pin rotatably held at the distal end of a thin metal tube is inserted from the rear end side, and is pressed and deformed in a tapered shape over the entire outer surface of the distal end, and the distal end surface is orthogonal to the side surface of the thin metal tube. After pre-constriction processing, a ball holding hole is formed with a drill having the optimum diameter. Then, the tip of the thin metal tube is pressed and deformed inward at multiple locations to form an inwardly protruding part, forming a ball receiving seat. After mounting the ball there, the tip edge is crimped inward to produce a chip. Method of manufacturing a ballpoint pen tip. 2. A core pin rotatably held at the distal end of a thin metal tube is inserted from the rear end side, and is pressed and deformed in a tapered shape over the entire outer surface of the distal end portion, and the distal end surface is orthogonal to the side surface of the thin metal tube. After pre-constriction processing, a ball holding hole is formed with a drill having the optimum diameter. Thereafter, an ink guide core having a capillary action is inserted from the rear end by a plurality of slits in the axial direction to form a receiving seat, and after mounting a ball there, the tip edge is caulked inward to produce a chip. Manufacturing method of ballpoint pen tip.