JP4608115B2 - Ballpoint pen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ballpoint pen in which an ink having shear thinning viscosity and a grease-like follower that follows the ink as it is consumed are directly packed in a shaft cylinder.
[0002]
[Prior art]
Conventionally, a water-based ink ballpoint pen is well known as a direct-filling type ballpoint pen in which ink is directly stored in a shaft cylinder. Recently, a ball-point pen is also provided as a product in which an ink having shear thinning viscosity and a grease-like follower that follows the ink consumption are directly packed in the shaft cylinder.
[0003]
[Problems to be solved by the invention]
The ballpoint pen structure, in which ink having shear thinning viscosity and grease-like followers are directly packed in the shaft cylinder, is a ballpoint pen tip in which the ball is rotatably provided at the tip of the shaft cylinder made of synthetic resin. The rear end portion of the chip holder or the tip end portion of the chip holder with the ball-point pen tip attached to the front end portion is mounted by press fitting.
[0004]
Incidentally, as shown in FIG. 5, in the conventional ballpoint pen 41 in which the ink having shear thinning viscosity is directly packed in the shaft cylinder, the rear end portion 47 of the tip holder 46 is mounted on the front end portion 44 of the shaft cylinder 42. Since the inner wall 45 of the shaft cylinder 45 and the rear end portion 47 of the chip holder 46 are press-fitted to form a press-fitting fitting portion H, and the chip holder 46 is firmly press-fitted in order to be firmly fixed without falling off. Internal stress is always generated at the tip 44 of the shaft tube. In addition, stress is greatly applied to the tip opening 43 of the shaft cylinder and the vicinity thereof by the writing pressure at the time of writing. When such stress is applied, there is a problem that cracks are generated at the tip of the shaft tube. In particular, in the shaft tube having a structure in which the tip end portion 44 of the shaft tube is tapered so that the writing tip portion of the ballpoint pen tip 10 or the ball 11 at the time of writing is easy to see, the thickness at the tip opening portion 43 of the shaft tube is other than Since it is thinner than the thickness of the tip 44 of the shaft tube, there is a problem that cracks are likely to occur.
[0005]
In order to solve the above problem, the pressure input between the shaft cylinder and the rear end portion of the ballpoint pen tip or the chip holder is set low so that it is difficult to come off due to the characteristics of the material. Possible measures include selecting and using the material, or adhering, welding, etc., but if the compatibility between the resin forming the barrel and the resin forming the chip holder is not considered There is a problem that the manufacturing cost is not increased.
[0006]
In view of these problems, the present invention can be formed of a material that has a simple structure and is not conventionally formed of a specific material for the shaft tube, the ball-point pen chip, or the chip chip holder. Thus, it is an object of the present invention to obtain a ballpoint pen in which an ink having a shear thinning viscosity and a grease-like follower are directly packed in the shaft tube, in which cracks are unlikely to occur at the tip of the shaft tube.
[0007]
[Means for Solving the Problems]
The present invention provides a ballpoint pen tip in which a ball is rotatably provided at the tip of a shaft cylinder directly packed with ink having shear thinning viscosity inside and a grease-like follower that follows the ink consumption at the rear of the ink. In a ballpoint pen formed by press-fitting the end portion directly or the rear end portion of the chip holder with the ball-point pen tip attached to the front end portion, the ball pen chip or the tip holder at the front end side at least from the press-fitting fitting portion and the rear end portion of the tip holder The front end portion of the shaft cylinder facing the rear end portion has a non-press-fit fitting portion, and a first convex portion is provided at the rear end portion of the ballpoint pen tip or chip holder, and the first end portion of the shaft tube is provided with the first protrusion. A second convex portion facing the one convex portion is provided, and the first convex portion and the second convex portion are passed over and fitted .
[0008]
Further, the non-press-fit fitting portion is a space portion formed by a gap between the tip end portion of the shaft tube and the rear end portion of the chip or the chip holder.
[0009]
Further, the tip end portion of the shaft tube is tapered so that the diameter gradually decreases toward the tip opening portion of the shaft tube.
[0011]
The rear end portion of the ball-point pen tip or chip holder of the present invention and the non-press-fit portion at the tip end portion of the shaft cylinder opposed to the rear end portion are the rear end portion of the ball-point pen tip or chip holder and the tip end portion of the shaft tube. This means that the gap is zero or more.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. The same member and the same part are denoted by the same reference numerals. In the embodiment of the present invention, description of the cap is omitted, but the present invention is not limited to a ballpoint pen having a structure having no cap.
In the ballpoint pen 1 showing the first embodiment shown in FIGS. 1 to 3, the tip holder 6 is transparently formed of a resin such as polyacetal or polypropylene, and the shaft cylinder 2 is transparently formed of a resin such as polypropylene or acrylonitrile styrene. The rear end 7 is provided with a fitting hole 8 in the tip holder 6 having a small diameter, and a ballpoint pen tip 10 having a ball 11 rotatably provided at the tip is inserted into the fitting hole 8. The fitting hole 8 communicates with an ink passage 9 opened at the rear end. A tail plug 12 having an air flow passage 12 a is attached to the rear end of the shaft tube 2.
[0013]
The tip portion 4 of the shaft cylinder 2 has a tapered shape that is reduced in diameter toward the tip opening portion 3 of the shaft cylinder. When the rear end portion 7 of the chip holder 6 is attached to the shaft tube 2, the rear end portion of the chip holder A press-fit fitting portion H is formed by press-fitting the convex portion 5 having an inner diameter N formed on the tip end portion 4 of the shaft cylinder 2 smaller than the outer diameter M of the rear end portion of the chip holder. Since the tip portion 4 of the shaft tube is tapered toward the tip opening portion 3 of the shaft tube, the thickness J of the shaft tube at the tip opening portion 3 is equal to the thickness K of the tip portion 4 of the other shaft tube. It is thinner than that. (J <K)
[0014]
Further, by making the inner diameter L from the front end opening 3 to the convex portion 5 larger than the outer diameter M of the rear end 7 of the chip holder (L> M), the rear end of the chip holder is added to the front end 4 of the shaft tube. When the is attached, a space 15 is formed in the rear end 7 of the chip holder from the front end opening 3 to the front of the convex portion 5, and a non-press-fit fitting portion G is formed. It is preferable to form the non-press-fit fitting portion G by the space portion 15 because stress due to writing can be easily prevented.
[0015]
In the ballpoint pen 21 according to the second embodiment shown in FIG. 4, when the tip holder 26 is attached to the tip portion 24 of the shaft tube 22, the rear end portion 27 of the chip holder is formed in the tip portion 24 of the shaft tube 22. A press-fitting fitting portion H is formed by press-fitting the convex portion 25 having an inner diameter smaller than the outer diameter of the rear end portion 27 of the chip holder. A first convex portion 28 is formed on the rear end portion 2 of the chip holder, a second convex portion 29 is formed in the tip portion 24 of the shaft tube 22, and the first convex portion 28 and the second convex portion 29 are fitted over each other. It is combined. Except for this, a ballpoint pen 21 was obtained in the same manner as in the first embodiment. In the second embodiment, the inner diameter from the tip opening 23 of the shaft tube to the front of the convex portion 25 is made larger than the outer diameter of the rear end portion 27 of the chip holder, and the first convex portion 28 and the first The two convex portions 29 are also set so as not to have a press-fitting allowance, and when the chip holder 26 is attached to the front end portion 24 of the shaft tube 22, the rear end portion 27 of the chip holder 26 extends from the front end opening 23 to the front of the convex portion 25. The non-press fit fitting part G is formed by forming the space part 35 in this.
[0016]
By fitting the chip holder with press-fitting and overpass fitting, it becomes more difficult to remove than with press-fitting only, so even if the pressure input for press-fitting is set weak, it will not fall out easily, so more The stress due to can be reduced.
[0017]
The formation position of the press-fitting fitting portion in the present invention is not particularly limited, but as described above, stress is easily applied to the tip opening portion and the vicinity thereof, so that it can be formed in a place away from the tip opening portion. preferable.
[0018]
【The invention's effect】
Since the ballpoint pen that directly accommodates the ink having the shear thinning viscosity and the grease-like follower according to the present invention has the structure as described above, the shaft cylinder, the ballpoint pen tip and / or the tip tip holder are not formed of a specific material. It is possible to obtain a ballpoint pen that has a simple structure and can be formed of a conventionally used material, is hard to crack at the tip of the shaft cylinder, and has a shear-thinning ink and grease-like follower directly packed in the shaft cylinder. did it.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a ballpoint pen showing a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part in FIG.
FIG. 3 is an enlarged cross-sectional view of a main part before mounting the shaft cylinder and the chip holder in FIG. 1;
FIG. 4 is an enlarged cross-sectional view of a main part of a ballpoint pen showing a second embodiment of the present invention.
FIG. 5 is an enlarged cross-sectional view of a main part of a conventional ballpoint pen.
[Name of the code]
1 Ballpoint pen 2, 22, 42 Shaft tube 3, 23, 43 Shaft tube tip 4, 24, 44 Shaft tube tip 5, 25, Convex 6, 26, 46 Tip holder 7, 27, 47 Rear end 8 Fit Contact hole 9 Ink flow hole 10 Ball-point pen tip 11 Ball 13 Ink 14 Follower 15, 35 Space portion 28 First convex portion 29 Second convex portion G Non-press-fit fitting portion H Press-fit fitting portion

Claims (3)

The tip of the greasy follower straight packed the barrel to follow along with the rear ink consumption in the ink and the ink having a shear thinning therein, directly rear end of the ballpoint pen tip rotatably provided a ball Alternatively, in a ballpoint pen formed by press-fitting a rear end portion of a chip holder with a ball-point pen tip attached to a front end portion, the rear end portion and the rear end portion of the ball-point pen tip or chip holder at least on the front end side from the press-fit fitting portion. The front end portion of the shaft cylinder that is opposed has a non-press-fit fitting portion, and a first convex portion is provided at the rear end portion of the ballpoint pen tip or chip holder, and the first convex portion is provided at the front end portion of the shaft cylinder. A ballpoint pen characterized by providing second convex portions that face each other and fitting the first convex portion and the second convex portion .   2. The ballpoint pen according to claim 1, wherein the non-press-fit fitting portion is a space portion formed by a gap between a tip end portion of the shaft tube and a rear end portion of the tip or the tip holder.   3. The ballpoint pen according to claim 1, wherein a tip end portion of the shaft tube has a tapered shape with a diameter decreasing toward a tip end of the shaft tube. 4.

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