JPH0373375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a method for mass-producing ballpoint pens for water-based ink at low cost.

Conventional ballpoint pens with oil-based ink have disadvantages such as the ink lacks fluidity, requiring strong writing pressure, and the ink tends to harden and become impossible to write on. Recently, ballpoint pens with water-based ink have good fluidity and can be easily written on. has been well received.

Currently, however, when manufacturing ballpoint pen holders for water-based ink, the main method is to cut a solid round body of nickel alloy to the required length of the ball holder, and then mill the inside and outside of the round body to the required diameter in an oil bath to form a funnel. At present, the ball is formed into a shape, and then the ball is fitted into the lower end opening of the holder and the lower end of the holder is machined to hold the ball.

However, machining the holder base from a solid circular shape in this way not only had a severe disadvantage in terms of materials, but also required a tremendous amount of technical effort for machining. There were various disadvantages in terms of materials and manufacturing, such as the fact that shavings tend to remain on the surface, making it difficult to remove them.

The present invention has successfully achieved its intended purpose by using the following method as a result of studies to eliminate all of the conventional disadvantages mentioned above.

That is, as shown in the drawings of the embodiment, for example, the inner diameter is adjusted in advance to match the inner and outer diameters of the upper part of the holder.
A ready-made long nickel alloy pipe of 1.7 mm in outer diameter, 2.3 mm in outer diameter, or 0.3 mm in thickness is prepared, and the pipe is cut into a length required for the holder 1', for example, 5 m, and a large number of holder base tubes 1 are provided. The outer diameter of the upper half is an inner diameter that matches the outer diameter of the base tube of 2.3 mm, and the lower half is a funnel-shaped hole that gradually narrows downward toward the center, and the lower end connected to the funnel-shaped hole has an inner diameter of 1 mm. A receiving mold 2 having a female hole 3 having a small circular hole 3' having a length of 0.8 mm in millimeters, an upper part having an outer diameter matching the inner diameter of the holder base tube 1, and a lower part connected to the upper part. It is formed in the shape of a solid funnel of a similar shape that fits the lower funnel-shaped female hole 3 of the receiving mold 2, and is connected to the lower part of the funnel-shaped part and fits inside the small circular hole 3' of the female hole. A pressing die 4 is provided with vertical protuberances 4' formed at three equal intervals on the outer circumference of the circular portion 4, and as shown in FIG. The lower part of the pressing mold 4 is inserted into the upper part of the mother tube 1 vertically through the supporter S, and the lower part of the pressing mold 4 is inserted into the upper opening of the mother tube 1, and after being pressed down with a pressure of 100 kg, the pressing mold 4 is pulled up and the mother tube 1 is When the mother tube is pulled out, a funnel-shaped holder 1' is formed in the lower part of the mother tube, as shown in FIGS. Ru. Therefore, this time, the inner circumference of the small cylindrical part 7 was cut to an inner diameter that matched the outer diameter of 1.5 mm of the steel ball 9, leaving the upper part, to form a storage chamber 8 with a small gap h in the upper part. Ball 9 from the bottom
After inserting the
When the inward bending edge 10 is formed as shown by the dashed line in FIG. 4, the ball 9 is held in an interlocking manner with a small gap h on the upper surface and three longitudinal grooves 6 on the upper peripheral wall. Then, insert the ink guide core 11 inside the upper part of the holder 1', attach the holder, insert it into the tip hole 13 at the lower end of the pen shaft 12 through the member F, and insert the upper end of the ink guide core into the pen shaft 12. By inserting it into the ink storage material 14 inside, the ballpoint pen of the present invention is obtained as shown in FIG.

The present invention provides a ballpoint pen for water-based ink in the manner described above, and is inexpensive because it does not have the disadvantages in terms of materials and manufacturing that would be obtained by machining the conventional solid circular body in an oil bath. Not only can it be mass-produced efficiently, but the small gap at the top of the ball inserted into the small cylindrical part at the bottom of the holder reduces friction when the ball rolls, and the vertical grooves on the outer periphery help improve the guide core. The water-based ink is always smoothly supplied to the outer periphery of the ball, so this ballpoint pen has the great advantage of being able to write very lightly without stagnation of ink. This invention is extremely useful as a manufacturing method.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a longitudinal cross-sectional side view showing the process of forming the ball holder of this ballpoint pen using a receiving mold and a pressing die, and Fig. 2 is a holder formed from a base tube. FIG. 3 is an enlarged vertical cross-sectional view of the main part showing the state in which the ball is inserted into the cylindrical portion at the lower end of the holder, and an inwardly bent edge is formed at the lower end of the cylinder to hold the ball. FIG. 4 is a bottom end view of the same as above, and FIG. 5 is a vertical side view of the entire pen holder showing a state where the ball holder obtained according to the present invention is inserted into the tip hole at the bottom end of the pen shaft. . 1 is a holder base tube, 1' is a holder, 2 is a receiving mold, 3 is a female mold hole, 4 is a pressing mold, 5 is a male mold, 6 is a vertical groove, 7 is a small cylindrical part, 8 is a storage chamber, 9 is a ball,
10 is an inner bending edge, 11 is a guide core, 12 is a pen shaft, 13 is a shaft tip hole, 14 is an ink storage material, and h is a small gap.

Claims (1)

[Claims] 1 Cut a ready-made metal pipe such as nickel alloy to the required length to provide a holder base tube, and form the lower part of the base tube on the upper part of the receiving mold so that it is aligned vertically on the center axis of the funnel-shaped female hole. At the same time, from the upper opening of the mother tube, a solid funnel-shaped male mold formed in a similar shape to the female mold hole is inserted into the lower end of the pressing mold and pressed down, and a small gap is created at the inner upper part of the lower end. A funnel-shaped holder is formed which has a small cylindrical part with longitudinal grooves formed in multiple places on the circumferential wall, and the inner periphery of the small cylindrical part is cut into an inner shape that matches the outer diameter of the ball, leaving the upper part. Then, after storing the balls in the storage chamber, the lower end of the small cylindrical portion is squeezed to form an inwardly bent edge, and then an ink guiding core is placed inside the funnel-shaped inside of the holder. 1. A method for manufacturing a ballpoint pen, characterized in that the holder is inserted into a tip hole at the lower end of a pen shaft, and the upper end of the guide lead is connected to an ink storage material in the pen shaft.