JP2001146087A - Ball-point pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-point pen tip facilitating disposition of a spring therein and further being free of blurring of a trace of writing and a leakage of ink, in regard to the ball-point pen tip constituted by providing the spring pressing a ball against the inner wall surface of the fore end edge of the tip. SOLUTION: A ball is held rotatably in the fore end of a tip, and a ball seat which has an ink flow hole and radial grooves communicating with the ink flow hole and extending radially, in the center, and with which the ball comes into contact is provided in the tip. A coil spring of which the fore end is made a straight part is disposed so that the straight part is in contact with the rear end of the ball through the ink flow hole and presses the ball against the fore end edge of the tip. In this ball-point pen tip, the straight part is so doubled as to be turned back and the doubled part is brought into contact with the rear end part of the ball. The straight part and the doubled part are positioned in the ink flow hole, while the fore end of the doubled part is so disposed as to be positioned at the rear end of the ink flow hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballpoint pen tip having a spring having a straight portion for pressing a ball rotatably held in the tip against the inner wall surface of the tip end edge.

[0002]

2. Description of the Related Art Heretofore, many ballpoint pens have been provided with an ink containing cylinder filled with an ink having a shear-thinning viscosity and a grease-like follower that follows the consumption of the ink. In a ball-point pen in which ink having shear-thinning properties is directly packed in an ink storage tube, ink leakage from the tip of the ball-point pen tip is likely to occur due to vibration or impact when the tip of the ball-point tip is downward. For this purpose, as a ballpoint pen tip structure, the ball held rotatably at the tip of the tip is brought into contact with the rear end of the ball by a spring having a straight portion, and pressed against the inner wall surface of the tip tip edge. It is also known to make up mechanisms.

A relatively large ball held by a conventional ballpoint pen tip having a diameter of 0.7 mm or more has been noticed because of its smooth writing taste. A ballpoint pen having a ballpoint pen tip rotatably holding a ball of 0.7 mm or more is provided on the market, and some are provided as knock-type ballpoint pens.

[0004]

SUMMARY OF THE INVENTION The inventor of the present invention has proposed a ballpoint pen tip having a spring having a straight portion, in which the spring is easily arranged in the tip, and there is no blurring of the handwriting and ink leakage. As a result of examining the structure that does not have, the relationship between the ink circulation hole formed in the center of the ball seat and the straight
The following problems were found. When arranging the spring, the end face of the straight part is still cut, the edge or burr of the end part of the straight part is caught on the inner surface of the chip, the spring cannot be arranged at the predetermined position, and the ball is not pressed. May occur. In addition, as the diameter of the ball increases, the amount of ink flowing out of the tip of the chip increases, and the diameter of the ink circulation hole formed in the center of the ball seat must be large so that the appropriate amount of ink flows out. However, the larger the diameter of the ink flow hole, the larger the amount of movement of the straight portion of the arranged spring in the ink flow hole, and the tip of the straight portion does not necessarily press the center of the ball. When the end of the ball is pressed, the farther away from the center of the ball, the more insufficient the function of the valve structure consisting of the ball and the inner wall of the tip end by the spring. Problem arises. However, if the wire diameter of at least the ink flow hole in the straight portion of the spring is increased, the diameter of the ink flow hole is substantially increased even if the diameter of the ink flow hole is increased so that the ink corresponding to the flow of the ink from the tip end flows out. In terms of the cross-sectional area, an area for the ink to flow out corresponding to the outflow of the ink is not obtained, and there is a problem that a sufficient ink outflow from the tip of the tip may not be obtained during writing.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a ball is rotatably held at the tip of a chip, and an ink circulation hole is formed in the center of the chip and communicates with the ink circulation hole. A ball seat having a radial groove extending radially is provided with a ball seat in contact with the ball, and a coil-shaped spring having a straight end at the tip is brought into contact with the rear end of the ball through the ink flow hole. In the ball-point pen tip which is disposed and presses the ball against the tip end edge, the straight portion is bent so as to be folded, the bent portion is brought into contact with the rear end of the ball, and the straight portion and the folded portion are formed by ink. It is located in the flow hole, and the leading end of the folded portion is located behind the ink flow hole.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. A ball-point pen tip 1 according to the present invention has an ink circulation hole 3 in the center and a radially extending radial line communicating with the ink circulation hole 3. A ball seat 4 having a groove 5 is provided, and the ball 6 is rotatably held in the ball holding chamber 2 with a part of the ball 6 protruding from the tip end edge 7.

[0007] A straight portion 1
A spring 8 having a coil-shaped spring portion 9 at the rear end of the straight portion 10, bending the straight portion 10 and bringing the bent portion 11 into contact with the rear end of the ball 6,
A part of the straight portion 10 and a part of the folded portion 11 are located in the ink circulation hole 3, and the leading end 13 of the folded portion 12 is located at the rear end of the ink circulation hole 3. The ballpoint pen tip 1 is disposed (not shown) so as to protrude from the rear end. The spring 8 is supported and fixed by a support portion (a step portion or the like) formed on an inner wall of a tip holder (not shown) for fitting the ballpoint pen tip 1 and supporting a rear end portion 8a of the spring. ing.

When the straight portion 10 is bent and the bent portion 11 is formed, the bent portion 11 has a rounded shape, so that when the spring 8 is disposed in the chip, it is difficult for the spring 8 to be caught in the chip. Further, by positioning the leading end 13 of the folded back portion 12 at the rear end from the ink circulation hole, a pressing force is applied to the ball at the time of writing or the like and the tip moves toward the rear end direction (the direction of arrow F in FIG. 1). The tip 13 of the spring does not get caught in the ink circulation hole 3, so that it can be smoothly moved in the axial direction.

Further, as shown in FIG.
If the width of the spring is H, it is better to bend the straight part if the wire diameter of the spring is large.
From FIG. 4, it is possible to obtain a large area for the ink to flow out in terms of the sectional area.

As another embodiment, in order to prevent the spring 8 from falling off from the ballpoint pen tip 1,
The rear end 8a of the spring 8 may be in contact with a portion having a reduced diameter at the rear end of the ballpoint pen tip 1. Alternatively, instead of reducing the diameter of the rear end of the ballpoint pen tip 1, a spring support member having an ink flow passage may be pressed into the rear end of the ballpoint pen tip 1 so as not to fall off the ballpoint pen tip 1. Alternatively, in a metal ink container that directly holds a ballpoint pen tip, a bead-shaped support portion that protrudes inward is formed on the inner wall surface of the ink container, and the rear end of the spring is supported by the support portion. In such a case, it may be arranged in the ballpoint pen tip.

[0011]

Since the ball-point pen tip of the present invention has the above-described structure, a spring can be easily arranged in the tip, and a structure free from blurring of handwriting and ink leakage can be obtained.

Further, as the diameter of the ball increases, the outflow of ink from the tip of the chip naturally increases. Therefore, the internal structure of the chip must be structured so that the outflow of ink increases. Because of the size, the ballpoint pen tip of the present invention is particularly effective.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a tip portion of a ballpoint pen tip of the present invention.

FIG. 2 is a view of the spring in FIG. 1;

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 2 and a virtual view of a spring at a width (wire diameter) H.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ball-point pen tip 2 Ball holding room 3 Ink circulation hole 4 Ball seat 5 Ink circulation groove 6 Ball 7 Tip end edge 8 Spring 9 Coiled spring part 10 Straight part 11 Bent part 12 Folded part 13 Tip

Claims (1)

[Claims] 1. A ball is rotatably held at the tip of a chip,
In the chip, a ball seat having the ink contact hole and a radially extending radial groove communicating with the ink contact hole at the center, the ball contacting the ball is provided, and the tip of the coil-shaped spring having a straight portion is straightened. In the ball-point pen tip, the part is disposed in contact with the rear end of the ball through the ink circulation hole, and the ball is pressed against the tip end edge.
The straight portion is bent so as to be folded, the bent portion is brought into contact with the rear end of the ball, and the straight portion and the folded portion are positioned in the ink circulation hole, and the leading end of the folded portion is located behind the ink circulation hole. A ballpoint pen tip, which is disposed at an end.