JP3235355B2 - Method for manufacturing ballpoint pen tip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a ballpoint pen tip having a ball as a writing member which is partially protruded from an inner hole and held by forming a reduced diameter portion by caulking the tip.

[0002]

2. Description of the Related Art Conventionally, in order to hold a ball made of a metal ball pen tip made of brass, nickel silver, stainless steel, copper alloy, aluminum alloy or the like, a center hole of the ball pen tip and a ball holding chamber. After the inside of the ball pen is formed by cutting or the like, the ball is inserted into the ball holding chamber, the tip of the tip of the ball pen tip is caulked inward, and the reduced diameter portion is formed to form the ball. There is known a ball-point tip that holds a ball.

[0003] Since the ball pen projects ink from the gap between the reduced diameter portion and the ball formed by the caulking process, the size of the gap between the reduced diameter portion and the ball greatly affects the quality of handwriting. I do. In general, when the gap is set to be large, the ink ejection amount increases, so that a thick handwriting can be obtained. In order to set this gap large, the caulking force of caulking is adjusted to reduce the amount of diameter reduction. When caulking, the ball is pushed up from the inside of the ball pen tip with another member, and the ball is pushed up With caulking in a state where it has been cut to regulate the amount of diameter reduction,
Also, after forming a reduced diameter portion by caulking, a pressing force is applied to the ball in the longitudinal direction from the tip of the ball pen tip, and the ball receiving seat portion is depressed and deformed by the ball, and the amount of deformation In this case, a gap between the reduced diameter portion and the ball is secured.

[0004]

However, setting a large gap between the reduced diameter portion and the ball causes a new problem in writing feel, that is, smooth rotation of the ball. Was something. That is, to set a large gap between the reduced diameter portion and the ball means to increase the volume of the ball holding chamber of the ball pen tip with respect to the volume of the ball. Means that the surrounding space becomes larger. In writing, a ball pen that discharges ink by rotating the ball preferably has a uniform rotation of the ball as much as possible, that is, it is preferable that the center of rotation of the ball is one point. It is not preferable that the rotating ball moves in the ball holding chamber. Each time the rotating ball moves, extra force is applied to the ball and the inner wall of the ball holding chamber that comes into contact with the ball, resulting in poor writing feel and the sound of metal collision. There is a problem that a so-called squeal phenomenon occurs.

Further, after forming the reduced diameter portion by caulking, a pressing force is applied to the ball in the longitudinal direction from the tip of the ball pen tip, and the ball receiving seat portion is depressed and deformed by the ball. In this case, the contact area between the ball and the ball receiving seat increases, and the ball closes the opening of the ink passage for supplying ink into the ball holding chamber. Not only is the supply of ink of the type greatly restricted, but also balls and balls
The friction with the ball receiving seat also increases, and the rotation of the ball is suppressed, so that the writing feeling is also reduced.

[0006]

According to the present invention, a ball as a writing member is partly protruded from an inner hole and held by forming a reduced diameter portion by caulking the tip. In the method for manufacturing a ball-tip, when a caulking process is performed on the inner hole of the ball-point tip, the temporary receiving portion for receiving the ball is arranged at a position where the ball does not contact the ball receiving seat. After forming the reduced diameter portion, a pressing force is applied to the ball in the longitudinal direction from the ball pen tip end side,
The ball pen tip is formed by deforming the temporary receiving portion by the movement of the ball and bringing the ball into contact with the ball receiving seat portion to form a gap between the reduced diameter portion and the ball. A summary of the manufacturing method.

[0007]

FIG. 1 is a sectional view of a principal part for explaining a ballpoint pen A manufactured according to the present invention. The ball pen tip A basically includes a large diameter portion 1 and a small diameter portion 2, and serves as a portion connecting the small diameter portion 2 to an ink tank or the like. The large-diameter portion 1 has a taper portion 3, the tip of which is a reduced-diameter portion 4 formed by caulking. The reduced diameter portion 4 forms an opening at the tip of the ball pen tip of the inner hole 5 which is an ink passage. The inner hole 5 is provided with a ball holding chamber 5a for holding a ball 6 as a writing member by partially protruding from an opening at the tip of the ball pen tip and opening the ball holding chamber 5a to supply ink. It has a central hole 5b to supply and a radial groove 5c.

The ball pen tip A of this embodiment is based on the assumption that a high-viscosity and quick-drying ink such as a correction liquid is used as the ink. A ball 6 is provided in the inner hole 5 on the tip side. A biasing coil spring 7 is arranged. After processing the shape of the ball pen tip A, the coil spring 7 is inserted into the inner hole 5 from the ink tank (not shown) side, and locked by the locking portion 8b formed in the inner hole 8a of the chip holder 8. Have been. The ball 6 is formed by this coil spring 7.
It presses against the reduced diameter portion 4 of the tip of the pen and suppresses leakage of the ink and drying of the ink in the chip.

The ball holding chamber 5a has a center hole 5b and a radial groove 5c, and has a ball receiving seat 9 which is in contact with the ball 6. In writing, the ball receiving seat portion 9 receives the writing pressure applied to the ball 6. Further, an inwardly protruding portion 10 is formed on the inner side wall of the ball holding chamber 5a to suppress the movement of the ball 6 during writing. The inward protruding portion 10 is a temporary receiving portion of the ball 6 when forming the reduced diameter portion 4 which is caulked to hold the ball 6, and a considerable portion of the outer wall of the ball pen tip A Is formed by applying a pressing force by a pressing tool to deform. Here, the number of the inwardly protruding portions 10 may be one or more, and can be appropriately formed as long as the flow of the ink and the rotation of the ball are not hindered. It is preferable that the ball 6 is formed at a target position so that the position of the ball 6 is stably maintained.

FIG. 2 and FIG. 3 are cross-sectional views of a principal part for explaining a method of manufacturing a ball-point tip according to the present invention. FIG. 2 shows a caulking process for forming the reduced diameter portion 4, and FIG.
This shows a step of applying a pressing force to the ball in order to contact the ball receiving seat portion 9. As shown in FIG. 2, the ball 6 is received by an inward protruding portion 10 which is a temporary receiving portion of the ball 6 formed on the inner side wall of the ball pen tip A.
In this state, the ball 6 is not in contact with the ball receiving seat 9. In this state, a pressing force is applied to the tip of the ball pen tip A while rotating the roll 12 to form a reduced diameter portion, thereby preventing the ball 6 from jumping out. In the caulking process, the reduced diameter portion 4 is brought into contact with the ball 6, so that the inner wall surface of the reduced diameter portion 4 is pressed against the ball 6 to become a smooth surface, and the rotation of the ball is reduced. This contributes to smoothing.

In the step shown in FIG. 3, a pressing force is applied to the ball 6 by the pressing pin 13 in the longitudinal direction of the ball pen tip A. With this pressing force, the ball 6 deforms the inwardly protruding portion 10 to contact the ball receiving seat portion 9 and at the same time forms a gap 11 between the reduced diameter portion 4 and the ball 6. . Considering the so-called springback phenomenon, which is a restoring effect on the pressing force of the metal material, the pressing force is not stopped at the position where the ball 6 and the ball receiving seat 9 come into contact with each other, but the pressing force is further increased. The ball 6 can be brought into contact with the ball receiving seat 9 after the springback phenomenon. That is, the pressing force applied to the ball 6 further presses the ball receiving seat portion 9 more than the state where the ball receiving seat portion 9 is in contact with the ball 6,
The shape of the ball 6 may be transferred to the ball receiving seat 9 by deforming the ball receiving seat 9. However, the ball 6 of the completed ball pen tip and the ball receiving seat 9 need not necessarily be in contact with each other.

FIG. 4 is a sectional view of a main part showing another embodiment of the present invention. In the example shown in FIGS. 2 and 3 described above, the inward protruding portion 10 for temporarily receiving the ball 6 when forming the reduced diameter portion 4 is replaced by a corresponding portion of the outer wall of the ball pen tip A. Is deformed by applying a pressing force to the inwardly protruding portion 10, but in this example, another method of forming the inwardly protruding portion 10 will be described. Inner hole 5 by cutting, etc.
Having radial cutting blades 14a formed on
H is inserted through the opening of the tip of the ball pen tip A,
A groove 15 is formed in the side wall of the ball holding chamber 5a. The number, depth, width, etc. of the grooves 15 may be set appropriately according to the number, length, and width of the cutting blades 14a of the broach 14. Ball pen tip A
The metal piece cut by the cutting blade 14a is
4 are left as burrs at a portion corresponding to the front end. The burr is used as an inwardly protruding portion 10 for a temporary receiving portion of the ball 6. The following steps are the same as those shown in FIGS.

As described above, by forming the inwardly protruding portion 10 by broaching, there is an advantage that the inwardly protruding portion 10 can also be formed only by processing the ball pen tip A in the longitudinal direction. In addition, the processed ball pen tip can increase the capacity of the ball holding chamber by the amount of shaving the inward protruding portion 10, and has an opening at the tip of the ball pen tip of the inner hole 5, which is an ink passage. The gap 11 with the ball 6 can be increased, and the ink discharge amount can be set to a large amount.

FIG. 5 is a cross-sectional view of a principal part for explaining still another method of forming the inwardly protruding portion 10. When the ball holding chamber 5a of the ball pen tip A is formed by cutting, an inwardly projecting portion as a temporary receiving portion of the ball is formed as a step portion 16. After that, by forming the radial groove 5c, the step 16 is made into a plurality of inwardly protruding portions, and the passage of the ink is secured. At this time, if the cutting blade for processing the step portion 16 has a large diameter portion and a small diameter portion, the step portion 16 can be formed simultaneously with the formation of the ball holding portion 5a.
The work becomes easier.

[0016]

As described above, according to the ball pen tip manufacturing method of the present invention, the writing feel is good, the ball can be rotated uniformly, and the sound of collision between metals is generated. It is possible to provide a ball pen tip capable of minimizing this and providing abundant supply of ink into the ball holding chamber.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a ball pen tip manufactured according to the present invention.

FIG. 2 is an explanatory view showing an embodiment.

FIG. 3 is an explanatory view showing an embodiment.

FIG. 4 is an explanatory view showing another embodiment.

FIG. 5 is an explanatory view showing still another embodiment.

[Explanation of symbols]

 A ball pen tip 1 large diameter part 2 small diameter part 3 taper part 4 reduced diameter part 5 inner hole 6 ball 5a ball holding chamber 5b center hole 5c radial groove 6 ball 9 ball receiving seat Part 10 Inwardly protruding part 11 Gap 12 Caulking roll 13 Press pin 14 Broach 14a Cutting blade 15 Groove 16 Step

Claims (1)

(57) [Claims] 1. A method for manufacturing a ballpoint pen tip, wherein a ball as a writing member is partially protruded from an inner hole and held by forming a reduced diameter portion by caulking the tip. Forming a temporary receiving portion for receiving the ball when caulking the inner hole of the pen tip so that the ball does not come into contact with the ball receiving seat; After forming the ball, a pressing force is applied to the ball in the longitudinal direction from the tip side of the ball pen tip to deform the temporary receiving portion by the movement of the ball and contact the ball with the ball receiving seat portion. And a gap is formed between the reduced diameter portion and the ball.