JP2003118285A - Barrel of writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that the adhesive strengths of the front and rear end parts in the direction along the axis of the grip member comprising a thermally adhesive elastomer applied to the recessed part of a barrel main body by two-color molding act only on a planar erected surface heretofore and, therefore, a contact surface is small and sufficient adhesive strength is not obtained and, when the force for moving the grip member forwardly and rearwardly by the fingers gripping the grip part acts, the end part of the grip member weak in adhesive strength is peeled and shifted as a result. SOLUTION: The front end surface and/or rear end surface in the direction along the axis of the recessed part formed at the grip part of the barrel main body is inclined so as to be expanded from the bottom surface of the recessed part toward the outer surface of the barrel main body. Further, the front end surface and/or the rear end surface is formed into a wavy shape undulated before and behind the direction along the axis of the recessed part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barrel of a writing instrument in which a grip portion of a barrel body is formed with a recess, and a grip member made of an elastic resin is attached to the recess by injection molding.

[0002]

2. Description of the Related Art Conventionally, in order to make it easier to grip a writing instrument, a shaft cylinder in which a grip portion of the shaft cylinder body is covered with a grip member made of an elastic resin such as silicone rubber or elastomer is well known. From Japanese Unexamined Patent Publication No. 10-297161, there is known a barrel in which a heat-adhesive elastomer is two-color molded and a grip member is attached to a recess of a grip portion of a barrel body.

The shaft cylinder of the writing instrument will be described in detail with reference to FIG. 7 (the upper half is a cross section). The shaft cylinder 100 has a front end face 107 of a recess 103 formed in a grip portion 102 of a shaft cylinder body 101. The rear end surface 108 and the bottom surface 104 are perpendicular to the outer surfaces 105 and 106 of the barrel body 101, and further, the front end surface 107 and the rear end surface 10 are formed.
8 is flat, and the concave portion 103 is covered with a gripping member 109 made of a heat-adhesive elastomer.

[0004]

Therefore, since the adhesive force of the gripping member 109 to the front end face 107 and the rear end face 108 acts only on the flat standing surface, the contact area is small and a sufficient adhesive force is obtained. When the force that cannot be obtained and the gripping member 109 moves back and forth by the finger gripping the gripping portion, the end of the gripping member 109 with weak adhesive force is peeled off, and as a result, the end is displaced. There was a problem.

In order to solve these problems, the present invention focuses on increasing the adhesive force by increasing the contact area of the front end surface and / or the rear end surface of the recess with the grip member, and grips the heat-adhesive Etomer. The present invention was devised by increasing the adhesive force to the front end surface and / or the rear end surface of the member, thereby making it difficult for the front end surface and / or the rear end surface of the gripping member to be turned up. An object of the present invention is to provide a barrel of a writing instrument in which the front and / or rear ends of the gripping members attached to the grips of the barrel of the writing instrument are unlikely to shift.

[0006]

Next, the barrel of the writing instrument of the present invention devised to solve the above problems will be described.
"1. In a barrel of a writing instrument, in which a recess is formed in a grip portion of a barrel body, and a grip member made of a thermo-adhesive elastomer is attached to the recess by injection molding, the direction along the axis of the recess 2. The front end face and / or the rear end face of the above is inclined so as to widen from the bottom surface of the recess toward the outer surface of the barrel main body 2. The front end face and / or the rear end face, It is characterized in that it is formed so as to widen from the bottom surface of the recess toward the outer surface of the barrel body, and is formed in a wavy shape that undulates in the front-back direction in the direction along the axis. "

In the present invention, a thermoadhesive elastomer is used as the grip member. The thermoadhesive elastomer is used as a material to be adhered by introducing a functional group that electronically interacts with the resin to be adhered. It is a resin that can be heat-bonded to other resins. For example, a styrene block copolymer-based thermoplastic resin adheres to polypropylene, polyethylene, polystyrene and the like with a certain degree of compatibility, but polycarbonate, ABS resin (acrylic / butadiene / styrene resin), polymethylmethacrylate, etc. As described above, it tends to be difficult to adhere to a resin having a polar group.
Therefore, by introducing the above-described functional group into a styrene block copolymer-based thermoplastic resin, thermal adhesion to almost all resins is enabled. Adhesion strength, oil resistance,
It is preferable to consider the hardness and the change in performance over time.

The wavy shape in the present invention refers to a sine wave, a rectangular wave, a sawtooth wave, a triangular wave, etc., which are uneven in the front and rear directions in the direction along the axis. In particular, the sine wave wavy shape smoothly undulates in the front-back direction of the wave as compared to other wavy shapes, so that it is possible to prevent the part from curling up even if it is rubbed with a finger. .

In the present invention, the front end face and / or the rear end face in the direction along the axis of the recess is inclined so as to widen from the bottom surface of the recess toward the outer surface of the barrel body. This is because the contact area between the front end surface and / or the rear end surface of the recess and the corresponding end of the gripping member is increased to increase the adhesive force.

Further, the front end face and / or the rear end face is
Forming in a corrugated shape that undulates back and forth in the direction along the axis allows the contact area to be further increased to further increase the adhesive force, and the ends of the barrel body and the gripping member are corrugated. This is because the meshing is performed in the shape of a hook, and thus the synergistic effect of preventing the gripping member from being displaced in the rotation direction can be achieved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, in order to facilitate understanding of the present invention, description will be given with reference to the drawings. In the present embodiment,
Although the description will be made using the ball-point pen barrel as the barrel of the writing instrument, the present invention is not limited to the barrel of the ball-point pen, and the barrel of various kinds of writing instruments such as mechanical pencils and felt-tip pens can be used. Further, in the present invention, the tapered portion side of the barrel is expressed as the front side, and the opposite side is expressed as the rear side.

The barrel of the ball-point pen of the present embodiment shown in FIGS. 1 to 4 will be described. FIG. 1 shows a side view of the barrel, the upper half of which is a cross section. 2 is an enlarged view of a main part in FIG. 1, FIG. 3 is a view of a barrel body, and FIG. 4 is a view of a barrel. The barrel 1 has a tapered portion 3 formed in a tapered shape in front of the barrel body 2, and a recess 5 is formed in a grip portion 4 behind the tapered portion 3. The recess 5 has a bottom surface 6
And a front end surface 9 and a rear end surface 10 which connect the front and rear of the bottom surface 6 and the outer surfaces 7, 8 of the barrel body 2 to each other.

In the barrel body 2, a tip opening 11 is formed in the tapered portion 3 so that a ballpoint pen tip (not shown) can be projected, and a rear end opening 12 is formed behind the shaft portion. At the same time, a female screw portion 13 is formed on the inner surface of the rear end opening 12. A rear member (not shown) of the ballpoint pen can be screwed.

The concave portion 5 of the present embodiment is formed by vertically erecting the front end face 9 from the bottom face 6, and the rear end face 10 is formed.
Is inclined so as to widen from the bottom surface 6 of the recess 5 toward the outer surface 8 of the barrel body 2, and is formed in a sinusoidal waveform that undulates back and forth in the direction along the axis. is there. The rear surface and the side surface of the grip member 14 made of a thermo-adhesive elastomer are adhered to the recess 5 having such a shape so as to adhere to the bottom surface 6, the front end surface 9 and the rear end surface 10.

The shaft cylinder 1 of this embodiment includes a shaft cylinder body 2
And the holding member 14 are formed by two-color molding. Next, the outline of the process of forming the barrel 1 will be described with reference to FIGS. It should be noted that, in FIGS. 3 and 4, drawings such as a mold in the forming process are omitted. FIG. 3 is a diagram showing a state in which the barrel body is formed by the primary mold. FIG. 4 is a diagram showing a state in which the grip member is attached to the barrel body by the secondary side mold.

In FIG. 3, the barrel body 2 is formed by injecting a polycarbonate resin between the primary die and the core pin. In this primary molding, the barrel body 2
The concave portion 5 is formed in the tapered portion 3 and the grip portion 4. still,
As shown in FIG. 3, the rear end surface 10 is inclined so as to widen from the bottom surface 6 of the recess 5 toward the outer surface 8 of the barrel body 2, and a sine wave that goes around the barrel body 2 is formed. Is the waveform shape. Further, the inner surface shape of the barrel body 2 is formed by the outer shape of the core pin, but the core pin remains inserted until the secondary molding by the secondary mold.

In FIG. 4, the shaft cylinder 1 is formed by injecting a polyester-based thermoadhesive elastomer resin between the secondary side mold and the recess (not shown). In this secondary molding, the shaft cylinder 1 has a gripping member 14 attached to a recess (not shown), and the rear end of the gripping member 14 has a large sinusoidal wavelike rear end face 10 and a large slope. Bonded in the contact area. The rear end opening 12 of the barrel 1 is provided with a female screw portion 13 formed by pulling it out from the barrel body 2 while rotating the core pin before removing it from the secondary mold.

The shaft cylinder 21 shown in FIGS. 5 and 6 shows another embodiment, and FIG. 5 shows a side view of the shaft cylinder 21.
The upper half is a cross section. FIG. 6 is an enlarged view of a main part in FIG. The shaft cylinder 21 connects the rear end face 10 to the first sloped surface 10a that is sloped so as to expand from the bottom surface 6 of the recess 5 toward the outer surface 8 of the shaft cylinder body 2, and is connected to the sloped surface 10a. The second inclined surface 10b having a steeper inclination angle than the inclined surface 10a reaching the outer surface 8 of the shaft barrel body 2.
It consists of and. The other points are the same as those of the above-described embodiment, and thus the description thereof will be omitted.

[0019]

Since the present invention has the above structure,
Since the contact area between the front and / or rear end of the gripping member and the front end surface and / or the rear end surface of the recess formed in the barrel body is increased to increase the adhesive force, the gripping member attached to the recess The front end portion and / or the rear end portion of the is difficult to shift.

[Brief description of drawings]

FIG. 1 is a side view showing a barrel of a ballpoint pen according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is a diagram showing a state in which a barrel body is formed by a primary mold.

FIG. 4 is a diagram showing a state in which a grip member is coated on a barrel body by a secondary mold.

FIG. 5 is a side view showing a barrel of a ball-point pen according to another embodiment.

FIG. 6 is a diagram showing a state in which a barrel body of another embodiment is formed by a primary mold.

FIG. 7 is a side view showing a barrel of a ballpoint pen of a writing instrument having a conventional structure.

[Explanation of symbols]

1, 21 ... Shaft cylinder, 2 ... Shaft cylinder body, 3 ... Constricted portion, 4 ... Gripping portion, 5 ... Recessed portion, 6 ... Bottom surface, 7 ... Outer surface, 8 ... Outer surface,
9 ... Front end surface, 10 ... Rear end surface, 10a ... 1st inclined surface, 10b ... 2nd inclined surface, 11 ... Tip opening part, 1
2 ... Rear end opening, 13 ... Female screw part.

Claims (2)

[Claims] 1. A shaft cylinder of a writing instrument, wherein a recess is formed in a grip portion of a shaft cylinder main body, and a grip member made of a heat-adhesive elastomer is adhered to the recess by injection molding, along a shaft center of the recess. A barrel of a writing instrument, wherein a front end face and / or a rear end face of the writing instrument is inclined so as to widen from the bottom surface of the recess toward the outer surface of the barrel body. 2. The barrel of the writing instrument according to claim 1, wherein the front end surface and / or the rear end surface is formed in a wavy shape that undulates in the front-back direction in the direction along the axis.