JP2001121869A - Ball-point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a favorable close contact state between a tip ball and the inner edge of the ball holding part of a tip, realize a smooth writing touch, a more uniform handwriting and, at the same time, simplify an assembling work and reduce the number of parts and the production cost of a ball-point pen. SOLUTION: In a ball-point pen consisting of a tip T having a ball 2, a ball holding part 1 with a small-mounted inner edge at its tip, a center hole 4, a plurality of sagittal grooves 5 and an inner hole 6, a spring 7, which is arranged in the inner hole 6 of the tip 7, supports the ball 2 and closely contacting the ball 2 with the small-mounted inner edge of the ball holding part 1, a tip holder and an ink housing part, the spring 7 is composed of at least two portions of a rod shaft part 7a and a winding part 7b under the state that, at the tip side of the rod shaft part 7a, a large diametral part having an external size, which is nearly equal to the inner diameter of the center hole 4 and slidable against the center hole 4, and an irregular shaped-cross section is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen using a ball as a writing medium, and more particularly to a ballpoint pen for preventing direct current and backflow of ink from a chip.

[0002]

2. Description of the Related Art As an example of the prior art, Japanese Patent Application Laid-Open No.
No. 4394 is known. The claims of this publication include, in a knock-type ballpoint pen, which is equipped with a ballpoint pen refill so that the refill of the ballpoint pen can be shifted with respect to the barrel so that the writing tip can protrude and retract from the tip of the shaft. The refill has a tip of a ballpoint pen at the end of the joint and an ink storage tube at the rear, and forms an upright bar shaft at the tip of the spring at the inner hole of the tip. By pressing the rear end of the ball, the tip ball comes into close contact with the inner edge of the ball holding portion at the tip end, preventing ink from flowing out, and releasing the close contact between the tip ball and the inner edge of the ball holding portion of the chip by writing pressure A mechanism is provided to prevent direct current and backflow of the ink so that the ink can flow out with the rotation of the tip ball. The ink storage tube is filled with low-viscosity ink, and the rear end of the ink is filled. Ink knock-type ballpoint pen, wherein a follower to follow the ink is configured to be disposed along with consumption of. Has been described as ".

[0003] Japanese Patent Application Laid-Open No. 9-150596 discloses a movable member having a ball pressing portion for exposing a part of a tip from a tip edge to the outside and in contact with a rear end face of a rotatably held ball. There is disclosed a chip in which a coil spring is disposed in contact with the rear end face of the movable member so that the ball is constantly pressed against the inner wall surface of the tip end edge.

[0004]

In the above-mentioned prior art, the tip of an upright bar shaft formed at the front of the spring presses the rear end of the tip ball, and the tip ball is moved to the ball gripping portion at the tip of the tip. The advantage is that the direct current and the backflow of ink are prevented by the close contact with the inner edge of the tip, and the close contact between the tip ball and the inner edge of the ball gripping portion of the chip is released by the writing pressure, so that the ink can flow out with the rotation of the tip ball. Having. However, when the tip of the upright bar shaft is smaller in diameter than the inner hole of the tip, the tip of the bar shaft moves in one direction in the inner hole of the tip as the tip ball rotates. As a result, the pressing force and the pressing direction of the spring against the tip ball become uneven, and the close contact state between the tip ball and the inner edge of the ball holding portion of the chip deteriorates. This causes a problem in that it has an adverse effect on handwriting and writing taste during writing. Further, when a movable member or the like having a ball pressing portion in contact with the rear end face of the ball is provided instead of forming an upright bar shaft portion in front of the spring, the number of parts increases, and the work at the time of assembly is reduced. There has been a problem that it is more complicated and the cost is higher.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a ball, a ball holding portion having a small inner edge at the tip, a center hole, a plurality of arrow grooves and an inner hole. A spring disposed in the inner hole of the chip to support the ball and bring the ball into close contact with the inner edge of the fore edge of the ball gripper; a chip holder having an inner hole step at the front; In a ball-point pen including an ink storage portion connected to a rear portion, the spring is formed by at least two portions of a rod shaft portion and a winding portion, and at a tip side of the rod shaft portion, the inner diameter of the center hole is substantially equal to the inner diameter of the center hole. The gist of the present invention is to form a large-diameter portion having an outer dimension slidable with respect to the cross-section and having an irregular cross-section.

[0006]

1 and 2 show a first example. A ball 2 is rotatably attached to a ball holding portion 1 at the tip of the tip T. A ball receiving seat portion 3 and a center hole 4 serving as an ink flow passage are formed below the ball 2 in the drawing, and a radial arrow groove portion 5 for supplying ink to the ball 2 along the center hole 4 is formed. Have been. An inner hole 6 is formed below the center hole 4, and a spring 7 is provided in the inner hole 6. One end of the spring 7 is formed as a rod shaft portion 7a extending vertically upward and passing through the center hole 4, and the other end is formed as a winding portion 7b. The ball 2 is supported by the rod shaft portion 7a,
It is urged upward and is in contact with the tip inner edge 8 of the ball gripper 1. The spring 7 is preferably formed of a metal material such as a piano wire or a stainless steel wire, but may be formed of another metal material or a resin material as long as the material has elasticity. The lower outer periphery of the tip T is a small-diameter cylindrical portion 10. The small-diameter cylindrical portion 10 is assembled into the inner hole 9 provided above the chip holder H by press-fitting or the like, and the chip T is fixed to the chip holder H. Have been. Further, below the chip holder H, an ink container P is connected and fixed. Note that the tip holder H supports and fixes the rear end 10a of the small-diameter cylindrical portion of the tip T at the inner hole step 9a, and also supports the rear end 7d of the spring 7.

A large-diameter portion 7c is formed in a portion of the rod shaft portion 7a on the tip side of the rod shaft portion located in the center hole 4. The large-diameter portion 7c has an outer dimension substantially equal to the inner diameter of the center hole and slidable with respect to the center hole, and is formed in an irregular shape (an elliptical shape in this example) in cross section (FIG. 3). The reason why the cross-sectional shape is modified (elliptical) is to secure a sufficient ink flow passage while keeping the large diameter portion 7c in contact with the inside of the center hole 4. The large diameter portion 7c
The cross-sectional shape of may be any shape as long as it is an irregular shape and can secure the ink flow path, and may be a shape provided with a plurality of protrusions such as a cross or a star (FIG.
(See FIG. 5). In short, any shape may be used as long as a sufficient ink flow path can be secured.

Next, the operation will be described. As shown in FIG. 2, a large-diameter portion 7c formed in a rod shaft portion 7a of a spring 7 is slidably disposed along the inner wall of the center hole 4 in the center hole 4 of the tip T. Spring 7 is ball 2
Is biased upward in the drawing to come into close contact with the tip inner edge 8 of the ball gripper 1. At this time, the large diameter portion 7c is
The rod shaft portion 7a of the spring 7
Is not offset to the edge of the center hole 4, and the pressing force and the pressing direction of the rod 7 a toward the center of the ball 2 are kept uniform. Next, when the ball 2 is brought into contact with the writing surface, the ball 2 is pressed, and the pressing operation causes the ball 2 urged by the spring 7 to retreat slightly, so that the ink I passes through the ball gripping portion via the ball 2. 1 and is supplied to the writing surface through the inner edge 8 of the front end. Also at the time of writing, since the large diameter portion 7c of the spring 7 is in contact with the inner wall of the center hole 4, the rod shaft portion 7a of the spring 7 is biased to the edge of the center hole 4 by the rotation of the ball during writing. However, the pressing force and the pressing direction of the rod 7a toward the center of the ball 2 can be kept uniform. Next, when the ball 2 is detached from the writing surface, the spring 7 moves back to bring the ball 2 into close contact with the tip inner edge portion 8 evenly, thereby interrupting the ejection of the ink I.

FIGS. 6 and 7 show a modified example.
The description of the same parts as in the above example is omitted. In this example, the large diameter portion of the spring 7 is a large diameter portion 7e formed by bending the tip of the rod shaft portion 7a. Here, the bending angle for forming the large-diameter portion 7e may be any angle as long as the tip end face 7f of the rod shaft portion 7a is turned in the opposite direction to the ball 2 by folding the rod shaft portion 7a. It is desirable that the large-diameter portion 7e is formed such that the tip end face 7f is located below the center hole 4 in the drawing, that is, the tip end face 7f is located in the inner hole 6 of the chip T. .

Next, the operation will be described. A large-diameter portion 7e of a spring 7 is slidably disposed along the inner wall of the center hole 4 in the center hole 4 of the chip T, and a top 7g of the large-diameter portion 7e abuts the ball 2. The ball 2 is urged in the upward direction to bring the ball 2 into close contact with the tip inner edge 8 of the ball gripper 1. At this time, since the large diameter portion 7e is in contact with the inner wall of the center hole 4, the top 7g of the spring 7 does not shift to the edge of the center hole 4 and the top 7g of the ball 2 in the center direction.
The pressing force and the pressing direction are kept uniform. Even during writing, since the large-diameter portion 7e is in contact with the inner wall of the center hole 4, the top 7g does not shift to the edge of the center hole 4 due to the rotation of the ball in writing.
The pressing force and the pressing direction of the top portion 7g in the center direction can be kept uniform. According to this modification, the top portion 7g that contacts the ball 2 has a smooth curved surface,
The rotation of the ball 2 at the time of writing can be made smoother.

FIG. 8 shows another modification. The description of the same parts as in the previous example is omitted. In this example,
The large-diameter portion of the spring 7 is a large-diameter portion 7h formed by spirally winding the tip of the rod shaft portion 7a. here,
The winding of the large-diameter portion 7h does not need to be dense, and the winding of the large-diameter portion 7h may not have elasticity. FIG. 9 shows another modification. In this example, the large-diameter portion 7i is formed in a so-called lightning-like shape in which the tip portion of the rod shaft portion 7a is bent at least several times. According to these modifications, the large diameter portion can be formed continuously by an automatic machine, which is more advantageous in terms of cost.

It should be noted that all of the above-mentioned embodiments do not dispose a separate member between the ball 2 and the spring 7, but in terms of the number of parts and cost as compared with the case where a separate member or the like is disposed. Has been improved.

[0013]

According to the present invention, there is provided a ball gripping portion having a ball and an inner edge of a forehead at a tip, a chip having a center hole, a plurality of arrow grooves and an inner hole, and a ball disposed in the inner hole of the chip to support the ball. A spring for bringing the ball into close contact with the inner edge of the ball gripper, a chip holder having a stepped inner hole at the front, and an ink container connected to the rear of the chip holder. It is formed by at least two portions of a rod shaft portion and a winding portion, and has an outer dimension substantially equal to the diameter of the center hole and slidable with respect to the center hole on the distal end side of the rod shaft portion, and has a cross-sectional irregular shape. Since the large diameter portion is formed, the close contact between the tip ball and the inner edge of the ball holding portion of the chip is kept good, and also, when writing, a smooth writing taste can be achieved,
This makes it possible to obtain a more uniform handwriting without occurrence of scratches, dents and writing directionality. Also, the work of assembling and holding can be made easier, which contributes to reduction in the number of parts and cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a ballpoint pen according to the present invention.

FIG. 2 is an enlarged longitudinal sectional view of a main part of FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a cross-sectional view showing a modified example of a large diameter portion.

FIG. 5 is a cross-sectional view showing a modification of the large-diameter portion.

FIG. 6 is an enlarged vertical sectional view of a main part showing a modification.

FIG. 7 is a sectional view taken along line BB of FIG. 6;

FIG. 8 is an enlarged longitudinal sectional view of a main part showing a modification.

FIG. 9 is an enlarged longitudinal sectional view of a main part showing a modification.

[Explanation of symbols]

 Reference Signs List 1 ball gripping part 2 ball 3 ball receiving part 4 center hole 5 radial arrow groove part 6 inner hole 7 spring 7a rod shaft part 7b winding part 7c large diameter part 7d spring rear end part 7e large diameter part 7f tip end face 7g top part 7h large Diameter part 7i Large diameter part 8 Front inner edge part 9 Inner hole 9a Inner hole step part 10 Small diameter cylinder part 10a Small diameter cylinder rear part H Chip holder I Ink P Ink storage part T Chip

Claims (1)

[Claims] 1. A ball having a ball, a ball holding portion having a fore edge at the tip, a center hole, a plurality of arrows and a chip having an inner hole, and a ball disposed in the inner hole of the chip for supporting the ball. In a ball-point pen comprising a spring for bringing the ball into close contact with the inner edge of the grip, a tip holder having an inner hole step at the front part, and an ink storage part connected to the rear part of the tip holder, the spring is a rod shaft part. A large-diameter portion having an outer dimension substantially equal to the inner diameter of the center hole and slidable with respect to the center hole is formed at the distal end side of the rod shaft portion. A ballpoint pen characterized by being formed.