JPH06293195A - Tip for ball point pen - Google Patents

Abstract

PURPOSE:To provide a tip for a ball point pen, occuring no leakage and/or no ooze-out of ink, and high in sealing degree even when the tip is used for an ink pressurizing type ball point pen or the ink of the ball point pen has a low viscosity. CONSTITUTION:A ball hole 3 is provided on a tip B for ball point pen and the ball hole is communicated with an ink introducing port 5, then, an elastic body is put on the bottom surface of the ball hole 3. A hard ball 7 is supported elastically on the elastic body and the peripheral rim 32 of the ball hole is calked to contact the ball closely with the tip.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen tip. More specifically, the present invention relates to a ballpoint pen tip capable of sealing the inner surface of a hard ball by closely contacting the inner peripheral edge of the ball hole opening.

2. Description of the Related Art In a conventional ballpoint pen using a tip for a ballpoint pen, in order to prevent ink from leaking or blowing out, a cap provided with a rubber member that adheres to a hard ball inside is inserted into the ballpoint pen, or a hot melt adhesive is used. The outer surface seal structure is used in which the tip portion of the ballpoint pen tip is covered with a different polymer composition.

The cap provided with the rubber member therein has a complicated structure and is costly, and the method of coating the tip for a ballpoint pen with a polymer composition is such that the ballpoint pen reaches the user's hand. There is a problem that once the writing is started, it is no longer possible to prevent the ink from leaking and blowing out.

In order to solve the above-mentioned problems, according to the present invention, a hard ball 7 mounted in a ball hole 3 is elastically supported by an elastic body 6, and the hard ball 7 is closely attached to the inner peripheral edge 32 of the ball hole opening. Let In the invention of claim 2, the elastic body is a sphere, and in the invention of claim 3, the sphere is held by a rib provided on the inner circumference of the ball hole to prevent swinging.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
Explained by. In the figure, A is a barrel, B is a ballpoint pen tip, C is a tail plug, and barrel A is a metal or synthetic resin barrel, and a ballpoint tip B is fitted to the tip of the barrel and a tail plug C is tightly fitted to the end. However, the ink for the ballpoint pen is stored inside. The ballpoint pen tip B is made by cutting a metal such as stainless steel or injection-molding an engineering resin such as polyacetal resin, and has a collar portion 2 in contact with the middle of the outer periphery of the cylindrical body 1 and a ball hole 3 at the tip. A recess 4 is formed at the end, and an ink guide hole 5 is provided between the ball hole 3 and the recess 4.
Has been installed. The ink guide hole 5 includes a central hole 51 having a circular cross section and a plurality of radial grooves 52 extending radially from the central hole 51. A ball 6 made of an elastic material having a diameter slightly smaller than the diameter of the ball hole 3 is placed on the bottom surface 31 of the ball hole 3, a hard ball 7 is brought into contact with the ball 6, and then the tip of the tubular portion 1 is caulked toward the center to form a hard ball. 7 and the inner peripheral edge 32 of the ball hole opening are brought into close contact with each other. Ball 6 on bottom surface 31 of ball hole 3
It is desirable to form the concave portion 33 in order to prevent the rocking.
The ball-point pen tip B assembled in this manner is press-fitted through the tip opening of the barrel A, and the collar 2 is pressed against the tip of the barrel A. Then, the barrel A having the tip B mounted thereon is inverted, ink is injected, and the tail plug C is press-fitted to the end of the barrel A (upper in the inverted state). In this embodiment, an example in which the elastic body is a ball has been shown, but the same effect can be expected even if the elastic body has an appropriate shape such as a cylindrical body. In the embodiment shown in FIGS. 3 and 4, the ball 6A made of an elastic material has a slightly smaller diameter, and the periphery of the ball 6A is held by a rib 34 protruding from the peripheral wall of the ball hole 3. The ribs prevent the balls 6A from swinging and also prevent the ink from flowing due to a large diameter. Further, the head of the pen tip B for a ballpoint pen has a shell-like shape, and the flange portion 2 has a step portion 2B.

EFFECT OF THE INVENTION In the ballpoint pen tip of the present invention, since the elastic body elastically supports the hard ball and the hard ball is brought into close contact with the inner peripheral edge of the upper portion of the ball hole, even when used in an ink pressure type ballpoint pen, Even if the ink is a low-viscosity water-based ink or oil-based ink, the hard ball and the inner peripheral edge of the upper part of the ball hole are firmly adhered and the inner surface is sealed.
Even if the ballpoint pen is dropped or shaken,
Even in an environment with low atmospheric pressure, such as in high mountains, there is no ink leakage or blowout, and there are no accidents such as finger stains or writing surface stains.
In addition, since the inner surface of the ball has a great sealing effect, there is no need for parts or processes for outer surface sealing, and there is no risk of water or solvent in the ink volatilizing and fading, making writing impossible. But it's convenient.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a ballpoint pen equipped with a tip for a ballpoint pen according to a first embodiment.

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

FIG. 3 is a vertical cross-sectional view of a ballpoint pen tip according to a second embodiment.

4 is a horizontal cross-sectional view taken along line YY of FIG.

[Explanation of symbols]

 A shaft cylinder B tip for ball-point pen C tail plug 1 cylinder part 2 flange part 2A step part 3 ball hole 31 bottom surface 32 opening inner peripheral edge 33 recessed part 34 rib 4 recessed part 5 ink guide hole 51 center hole 52 radial groove 6, 6A From elastic material Ball 61 Depression 62 Through hole 7 Hard ball

Claims (3)

[Claims] 1. A ball-point pen tip, characterized in that a hard ball (7) mounted in a ball hole (3) is elastically supported by an elastic body (6) and the hard ball (7) is brought into close contact with an inner peripheral edge (32) of a ball hole opening. 2. The tip for a ballpoint pen according to claim 1, wherein the elastic body is a spherical body 6. 3. The ball-point pen according to claim 1, wherein the elastic body is a spherical body 6A having a diameter smaller than that of the hard ball 7, and ribs are provided on the inner circumference of the ball hole 3 in a vertical direction. Chips.