JPH0110230Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a ballpoint pen body that uses a rod-shaped body made of a core made of a wear-resistant material and a cylindrical body made of synthetic resin on the outer periphery thereof as a ball seat.

Ballpoint pen bodies having the above-mentioned structure are known to provide a ball seat that provides a good writing feel and has excellent abrasion resistance.

That is, Japanese Utility Model Publication No. 52-25225 discloses that a ball seat (receiving rod) consists of a metal receiving rod main body and a synthetic resin body fixed to the main body with the tip of the main body partially exposed. A ballpoint pen body constructed according to the present invention is disclosed.

However, in this ballpoint pen body, both the metal receiver body and the synthetic resin body function as a ball seat, so the writing tip is certainly a ball seat that provides a good writing feel. Although it is possible to shorten the writing distance, the synthetic resin body will wear out.
It had the disadvantage that it no longer worked as a ball catch, and in the end, it could not achieve its original purpose.

The present invention has been made based on the above-mentioned points, and will be described below with reference to an embodiment of the present invention shown in the drawings.

In the figure, reference numeral 1 is a chip made of metal, ceramic, etc., which rotatably holds a ball 2 by a tip portion 1a having a reduced diameter. Reference numeral 34 is a rod-shaped body disposed within the chip 1, which includes a core body 3 made of a wear-resistant material such as metal, ceramic, or carbonized resin, and a synthetic resin such as acetal, acrylic, or amide. The cylindrical body 4 is made of

The cylindrical body 4 of this embodiment having the ink guide passage 4a is preferably extruded around the core body 3, and a monofilament self-fusion method is preferably used. In addition, a previously formed cylindrical body 4 is placed over the core body 3 and heat-shrinked, or the core body 3 is
It is also possible to perform injection molding using a mold containing .

Although the cylindrical body 4 does not need to cover the entire outer periphery of the core 3, the tip 4b of the cylindrical body 4 is made to protrude beyond the core 3, and the extent of this protrusion is determined by ( A gap A is formed between the ball 2 and the core 3 (when the ball 2 is brought into contact with the tip 4b), and when pressure is applied to the ball 2 during writing, due to the elasticity of the cylindrical body 4. As a result, the gap A is eliminated,
Once the pen pressure is released, it is within the range of recovery as well.

The rod-shaped body 34 presses and deforms the chip 1 from the outside to form an appropriately shaped inward protrusion, which allows the chip 1 to be
When the rod 34 and the tip 1 are both fixed or supported by another member such as a tip holder, in other words, when the ball 2 is displaced backward during writing, the tip 1 is also fixed to the rod holder. 3
Regardless of the case where there is a relative displacement with 4,
In general, the gap A as described above will be small.

One of the easy ways to manage the gap A to a small size as mentioned above is to make the tip of the cylindrical body 4 protrude a little in advance, and deform it by pressing it against a heating element such as metal, so that the tip part 4b. The heating body may be the ball 2, and if you press the core body 3 until it comes into contact with the ball 2 and take advantage of the fact that when the synthetic resin cylindrical body 4 deforms, it deforms elastically as well as plastically, it is possible to By controlling the temperature and time, it becomes easy to form the gap A in mass production.

Suppose that the tip 4 of the cylindrical body 4 is removed by the method described above.
b is formed into the shape shown in FIG. 1, for example, when the ink drawn out from the ink chamber (not shown) is between the inner hole of the chip 1 and the outer wall of the rod-shaped body 34, capillary force is applied. If the ink is weak and there is a risk that the so-called ink drop phenomenon may easily occur, the third
As shown in the figure, the rear portion 1b of the tip 1 can also be made into a small diameter portion.

Although not shown, it is also possible to make the rear part of the cylindrical body 4 a large diameter part.
The outer wall of the cylindrical body 4 may be formed straight up to the tip without making the tip 4b of the cylindrical body 4 a large diameter part, as shown in FIGS. However, this does not change the gist of the present invention.

In the above-mentioned embodiment, a cylindrical shape is illustrated as the core 3, but a slit is formed in the longitudinal direction to form an ink passage between the core 3 and the cylindrical body 4 (from this point of view, the cylindrical body A slit can be formed on the inner wall side of the core body 4, or a cylindrical core body 3 can be used. You can also do things like

As described above, according to the present invention, the rod-shaped body 34 serving as a ball seat is composed of the core body 3 made of a wear-resistant material and the cylindrical body 4 made of synthetic resin existing on the outer periphery of the core body 3. This not only improves the writing quality, but also allows the core 3 to not come into contact with the ball 2 when no pressure is applied.
In addition, since the pen is in contact with the ball 2 when pressure is applied, writing progresses and the tip 4b of the cylindrical body 4
It will take a long time for the core body 3 to wear out and only the core body 3 will become a ball catch.
The good writing quality can be maintained for a long time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line of FIG. 1, and FIGS. 3 and 4 are longitudinal cross-sectional views showing other embodiments. 1...Tip, 1a...Tip (of the tip),
34... Rod-shaped body, 3... Core body, 4... Cylindrical body, 4
b...Tip part (of the cylindrical body).

Claims (1)

[Scope of utility model registration request] A ballpoint pen body in which a rod-shaped body serving as a ball receiving seat is arranged within a tip that rotatably holds a ball at the tip, the rod-shaped body comprising a core body made of a wear-resistant material, and an outer periphery of the core body. In a ballpoint pen body consisting of a cylindrical body made of synthetic resin, the cylindrical body is configured to provide a gap between the tip of the core body and the ball that can be eliminated according to the writing pressure during writing. A ballpoint pen body, characterized in that a tip protrudes from the core and resiliently receives the ball at the tip.