JP2003136881A - Ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a push rod from getting into the inside of the rear end part of a coil spring on the occasion when the coil spring is incorporated. SOLUTION: The ballpoint pen 1 has a tip main body 2, a holder 3 and the coil spring 4. At the fore end of the tip main body 2, a ball 21 is held rotatably by the inward fore end edge part 22 thereof. The holder 3 holds the rear part of the tip main body 2. The coil spring 4 urges the ball 21 forward and brings it into close contact with the inside of the front end edge part 22. A projection 31 is provided inside the tip main body 2 or inside the holder 3. In the rear end part of the coil spring 4, a large-diameter part 43 and a small-diameter part 44 which is provided rearward from the large-diameter part 43 continuously thereto are provided. The large-diameter part 43 is engaged with the projection 31 in a manner of getting over it. The small-diameter part 44 is deformed forward and held inside the large-diameter part 43 on the occasion when the coil spring 4 is incorporated by forward pressing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ballpoint pen. Specifically, a tip body having a ball rotatably held at the tip from an inward tip edge portion, a holder for holding a rear portion of the tip body, and urging the ball forward to tip the ball The present invention relates to a ballpoint pen having a coil spring that is brought into close contact with the inner surface of the edge portion.

[0002]

2. Description of the Related Art Conventionally, in this type of ball-point pen, for example, in Japanese Patent Laid-Open No. 10-329475, a coil spring for urging the transfer ball forward from the rear end opening is incorporated in the chip body. A configuration is disclosed in which the rear end of the coil spring is locked to a spring locking projection (spring locking convex portion) provided on the inner surface of the chip body.

In the conventional ballpoint pen, the rear end of the coil spring is pressed forward by the push rod while compressing and deforming the coil spring. The push rod has an outer diameter smaller than an inner diameter of the spring locking protrusion so that the push rod can be inserted into the spring locking protrusion. Therefore, when incorporating the coil spring, the push rod enters the inner surface of the rear end of the coil spring,
There is a possibility that the coil spring cannot be properly incorporated in the chip body.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. When the coil spring is assembled, there is no risk that the push rod will enter the inner surface of the rear end of the coil spring, and the coil spring can be properly secured. It is intended to provide a ballpoint pen that can be incorporated in a place.

[0005]

[1] A ball-point pen 1 of the present invention comprises a tip body 2 in which a ball 21 is rotatably held by an inward tip edge portion 22 at its tip, and a rear portion of the tip body 2. A ball-point pen having a holder 3 for holding the ball 21 and a coil spring 4 for urging the ball 21 forward to bring the ball 21 into close contact with the inner surface of the tip edge portion 22, the inner surface of the tip body 2 or the holder 3 A large-diameter portion 43 is provided on the inner surface of the coil spring 4, and a large-diameter portion 43 is provided at the rear end portion of the coil spring 4 so that the large-diameter portion 43 can be passed over and locked by the protrusion 31.
3 and a small diameter portion 44 which is connected to the rear of the large diameter portion 43 and which is deformed forward when the coil spring 4 is assembled by being pressed forward and is housed inside the large diameter portion 43 (claim 1). And

When the rear end portion of the coil spring 4 is pushed forward by the push rod 7 when the coil spring 4 is assembled, the small diameter portion 4
4 is deformed forward and is accommodated inside the large diameter portion 43. Therefore, a stable contact portion with the push rod 7 can be formed at the rear end portion of the coil spring 4. As a result, when the coil spring 4 is assembled, there is no risk that the push rod 7 will enter the inner surface of the rear end portion of the coil spring 4, and the large diameter portion 43 of the coil spring 4 can be reliably attached to the protrusion on the inner surface of the chip body 2 or the protrusion 31 on the inner surface of the holder 3. You can get over and lock. The holder 3 may be configured to also serve as the ink containing tube 5.

[2] In the ball-point pen 1 of claim 1, it is preferable that the large diameter portion 43 and the small diameter portion 44 are closely wound portions (claim 2).

The large diameter portion 43 and the small diameter portion 4 are formed by the closely wound portion.
The rigidity of the coil spring 4 is increased, and when it is pressed by the push rod 7, the coil spring 4 can be assembled more stably without wobbling.

[3] In the ball-point pen 1 of claim 1 or 2, the large diameter portion 43 is formed with an inclined portion 43a on the front surface thereof, the outer diameter of which decreases toward the front (claim 3).
Is preferred.

By providing the inclined portion 43a on the front surface of the large-diameter portion 43, the large-diameter portion 43 is provided with a protrusion 3 for locking the spring from the rear side.
When getting over 1, the large-diameter portion 43 can smoothly go over the projection 31 without being caught by the projection 31. Further, the inner surface of the inclined portion 43a of the large diameter portion 43 is pressed by the small diameter portion 44 which is deformed forward and is accommodated in the large diameter portion 43. Therefore, the coil spring 4 is much more stable.
Can be embedded. The outer surface of the inclined portion 43a may be, for example, a conical surface, a convex curved surface, a concave curved surface, or the like.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

(Embodiment) FIGS. 1 to 5 show an embodiment of the present invention. The ballpoint pen 1 of this embodiment has a ball 2 at the tip.
1. A chip body 2 that rotatably holds 1; a holder 3 in which the rear part of the chip body 2 is press-fitted and fixed to the front part; and an ink storage tube 5 in which the rear part of the holder 3 is press-fitted and fixed to a tip opening. A coil spring 4 housed and arranged inside the chip body 2 and inside the holder 3, and the ink containing tube 5
The tail plug 6 is press-fitted and fixed to the rear end opening.

The ink containing tube 5 is a cylindrical body having both ends opened, and is obtained by extrusion molding of synthetic resin. The rear portion of the holder 3 having the chip body 2 is press-fitted and fixed to the tip opening portion of the ink containing tube 5, while the tail plug having a vent hole penetrating the rear end opening portion of the ink containing tube 5. 6 is press-fitted and fixed. Inside the ink containing tube 5,
Ink 51 (for example, water-based gel ink imparted with shear thinning viscosity or medium viscosity oil-based ink), and the ink 51
It is filled with a grease-like follower 52 which is arranged at the rear end and which advances as the ink 51 is consumed.

The chip body 2 is made of metal (for example, S
It is made of a right cylindrical thin tube made of austenitic stainless steel such as US304 and SUS321. An annular inward tip edge portion 22 is formed at the tip portion of the tip body 2 by inward pressing deformation. Further, on the inner surface of the side wall of the chip body 22 behind the tip edge portion 22, three inward projecting portions 23 (that is, ball receiving seats) are formed at equal intervals in the circumferential direction by inward pressing deformation. The ball 21 is rotatably held between the inner surface of the tip edge portion 22 and the front surface of the inward protruding portion 23 (that is, the ball holding portion).

The holder 3 is a cylindrical body obtained by injection molding a synthetic resin (eg polypropylene, polyacetal, etc.). The holder 3 is a chip body 2
A front part having a tapered shape, a collar part that comes into contact with the front end surface of the ink containing tube 5, and a rear part that is press-fitted into the front end opening part of the ink containing tube 5. Inside the holder 3, there are provided a chip mounting hole having a tip opening to the outside, and an ink circulation hole having a tip communicating with the chip mounting hole and a rear end opening to the outside. On the inner surface of the intermediate portion of the ink circulation hole, a plurality of (for example, four) spring-locking projections 31 that are dispersedly arranged in a circumferential shape are integrally formed. The protrusion 31 may be formed in a ring shape.

The coil spring 4 is made of a stainless steel wire rod having a wire diameter of 0.14 mm, and a front rod portion 41 and a rear coil portion 42 are integrally connected to each other. At the rear end of the coil portion 42, a large-diameter portion 43 formed of a close-wound portion having an outer diameter larger than the outer diameter of the front coil portion 42 is formed. Further, behind the large-diameter portion 43, a small-diameter portion 44 composed of a close-wound portion is integrally provided.

The large-diameter portion 43 of the coil spring 4 rides over and is engaged with the projection 31 on the inner surface of the holder 3, and the coil portion 43 in front of the large-diameter portion 43 is accommodated and arranged in the holder 3 in a compressed state. Then, the rod portion 41 of the coil spring 4 is inserted into the chip body 2 and the tip thereof is brought into contact with the rear surface of the ball 21 to press the ball 21 forward, so that the front surface of the ball 21 and the inner surface of the tip edge portion 22 are annular. Close to.

In the ball-point pen 1 of this embodiment, when not writing, the ball 21 is pressed forward by the rod portion 41 of the coil spring 4, and the ball 21 and the inner surface of the tip edge portion 22 are brought into close contact with each other. The pen tip is sealed. This prevents ink from leaking from the pen tip even if the pen tip is stored facing downward, and prevents air from entering from the pen tip even when storing the pen tip facing upward.

In the present embodiment, the large-diameter portion 43 has an inclined portion 43a composed of three inclined contact winding portions on the front surface, a vertical portion 43b composed of vertical contact winding portions on the rear surface, and the inclination. A maximum outer diameter portion consisting of two straight cylindrical close-wound portions between the portion 43a and the vertical portion 43b is integrally connected.
The small-diameter portion 44 is composed of four windings of a close-cylindrical close-wound portion, and is continuously provided integrally with the vertical portion 43b. The maximum outer diameter of the large diameter portion 43 is set to 1.6 mm, and the outer diameter of the coil portion 42 in front of the large diameter portion 43 is 1.0 mm.
The outer diameter of the small diameter portion 44 is set to 1.0 mm (the same outer diameter as the coil portion 42).

(Coil Spring Assembly Process) The assembly process of the coil spring 4 of this embodiment will be described in order (FIGS. 2 to 5).
reference). First, as shown in FIG.
Is inserted from the rear end opening of the holder 3 to which the chip body 2 is fixed at the front. At this time, the coil spring 4 is in a free state (non-compressed state), the tip of the rod portion 41 is brought into contact with the rear surface of the ball 21, and the large diameter portion 43 and the small diameter portion 44 are located rearward of the protrusion 31 on the inner surface of the holder 3. Is located in.

Next, as shown in FIGS. 3 and 4, the push rod 7 pushes the rear end of the coil spring 4 forward. The push rod 7 is provided with a convex portion 71 having an outer diameter smaller than the inner diameter of the small diameter portion 44 at the tip, and on the outer periphery of the convex portion 71,
The annular contact surface 72 has an outer diameter larger than the outer diameter of the small diameter portion 44 and smaller than the outer diameter of the large diameter portion 43. The convex portion 71 of the push rod 7 is inserted into the small diameter portion 44, and the annular contact surface 72 of the push rod 7 pushes the rear end of the small diameter portion 44 and the vertical surface of the outer diameter portion 43 forward. As a result, the small diameter portion 44 is deformed forward and accommodated inside the large diameter portion 43, and at the same time, the inner surface of the inclined portion 43a of the large diameter portion 43 and the rear end of the coil portion 42 are pressed forward by the small diameter portion 44. To be done. Therefore, the large diameter portion 43 can surely get over the projection 31 on the inner surface of the holder 3 without pulling and deforming the coil portion 42 due to the push rod 7 entering the inner surface of the coil portion 42.

Finally, when the push rod 7 is pulled out from the inside of the holder 3, as shown in FIG.
The protrusion 31 on the inner surface is locked. In FIG. 5, at this time, the small diameter portion 44 returns to the original state in which it protrudes from the inside of the large diameter portion 43 to the outside, but the small diameter portion 44 does not return to the original state after the coil spring 4 is assembled. Maybe,
It may be stored in the large diameter portion 43.

[0023]

According to the first aspect of the present invention, when the coil spring is assembled, there is no risk that the push rod will enter the inner surface of the rear end portion of the coil spring, and the coil spring can be reliably incorporated in an appropriate place.

According to the invention of claim 2, the rigidity of the large-diameter portion and the small-diameter portion is increased, and when pressed by the push rod, there is no wobbling, and the coil spring can be assembled more stably.

According to the third aspect of the present invention, the coil spring can be assembled more stably.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of an essential part showing a coil spring in a free state immediately after insertion in the embodiment of FIG.

FIG. 3 is an enlarged vertical sectional view of an essential part showing the coil spring in a state of being pressed by the push rod of the embodiment of FIG.

FIG. 4 is an enlarged view of part A of FIG.

5 is an enlarged vertical cross-sectional view of essential parts showing a state where the coil spring of the embodiment of FIG. 1 is completely assembled.

[Explanation of symbols]

1 ballpoint pen 2 chip body 21 balls 22 Tip edge 23 Inward projection 3 holder 31 Protrusion 4 coil spring 41 Rod part 42 coil 43 Large diameter part 43a inclined part 43b Vertical part 44 Small diameter part 5 Ink storage tube 51 ink 52 Follower 6 tail plugs 7 push rod 71 convex 72 Annular contact surface

Claims (3)

[Claims] 1. A tip body having a ball rotatably held at its tip from an inward tip edge portion, a holder for holding a rear portion of the tip body, and biasing the ball forward to move the ball forward. A ball-point pen having a coil spring brought into close contact with the inner surface of the tip edge portion, wherein a projection is provided on the inner surface of the tip body or the inner surface of the holder, and a large-diameter portion that can be passed over the projection and locked at the rear end portion of the coil spring. And a small-diameter portion that is continuously provided rearward from the large-diameter portion and that is deformed forward when the coil spring is assembled by pressing forward and is accommodated inside the large-diameter portion. . 2. The ball-point pen according to claim 1, wherein the large-diameter portion and the small-diameter portion are contact winding portions. 3. The ball-point pen according to claim 1, wherein an inclined portion whose outer diameter decreases toward the front is formed on the front surface of the large-diameter portion.