JP2000313192A - Manufacture of lead protective tube of mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately form a hole without changing characteristics, physical properties of a resin such as adhesive properties or the like of a lead protective tube with small thermal diffusion by charging a resin in the tube, and removing a part of the charging resin by a laser beam to form a hole for feeding a lead. SOLUTION: A chuck 3 externally engaged with a forward outer periphery of a chuck ring 2 is disposed in a barrel 1 of the mechanical pencil, and a tip member 4 is mounted forward of the barrel 1 by threading or the like. A lead protective tube 5 made of a metal material or the like is mounted at a tip end of the member 4, a resin such as a reaction curable resin, a thermoplastic resin or the like is charged in the tube 5 to form a lead holding member 7. The resin formed in the tube 5 is partly formed in a length for holding the entirety or the lead in the tube 5, the part of the charged resin is removed by a laser beam, thereby completing the member 7 having a cylindrical or the like hole. As a laser medium of the beam, a ruby laser or the like is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lead protection tube for a mechanical pencil.

[0002]

2. Description of the Related Art In a mechanical pencil, when a lead is shortened during writing, the lead is released from a chuck such as a 30% chuck or a ball chuck for holding the lead which is a lead feeding mechanism. The core released from the chuck is
It will remain between the tip of the chuck and the tip of the mechanical pencil (core protection tube). The remaining lead (hereinafter referred to as a residual lead) is only lightly held by the lead detent member arranged in the mechanical pencil. Therefore, when writing is performed on the residual core portion, the core rotates and the writing feeling deteriorates. Therefore, the remnant is generally discarded by extruding the remnant or removing the remnant by a subsequent core. Furthermore, if the residual core is removed from the core detent member, the above-described phenomenon is remarkably observed, and the core may fall due to its own weight.

[0003] In order to make effective use of this residual core, proposals have been made for a core protective tube. For example, there is known a core protective tube in which an elastic thin film made of rubber or the like is integrally laminated on the inner surface (Japanese Utility Model Publication No. 58-32959).

[0004]

The core protection tube formed by this conventional technique can effectively utilize the residual core by means of an elastic thin film such as rubber, but has various problems in the manufacturing method. Was. Specifically, a molten synthetic resin or rubber is press-fitted and filled using a mold, and then cooled to form an elastic thin film on the inner surface of the core protection tube. However, in this manufacturing method, when the gap between the inner wall of the core protection tube and the mold installed inside the core protection tube becomes narrow, there is a problem that the molten synthetic resin, rubber, or the like cannot be press-fitted. In addition, it is necessary to apply a mold release agent or the like to the mold in order to increase the mold releasability between the mold and the elastic thin film, and there has been a problem that productivity, workability, and the like are reduced. On the other hand, after filling the inside of the core protection tube with an elastic resin or the like, when machining with a drill or reamer, the heat generated by the processing may deteriorate the physical properties of the resin layer or deteriorate the adhesion with the core protection tube. However, there is a problem that the dimensional accuracy is hardly obtained and the hole diameter varies.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of these problems, and has been made by filling a resin inside a core protection tube and removing a part of the resin with a laser beam. A method for manufacturing a core protective tube capable of accurately forming holes without changing the properties and physical properties of the resin (such as adhesion to the core protective tube) due to low heat diffusion, and using a mechanical pencil. A method for manufacturing a lead protection tube for a mechanical pencil, characterized in that a resin is filled in the inside of the lead protection tube, and a part of the resin is removed by a laser beam to form a hole for centering. It is assumed that.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic partial cross-sectional view of a mechanical pencil equipped with a lead protection tube according to the present invention.

Reference numeral 1 denotes a mechanical cylinder of a mechanical pencil. Inside the mechanical cylinder 1, a chuck body 3 in which a chuck ring 2 is externally fitted on the outer periphery of a front part (in the figure, a three-part chuck is shown). , Which may be a chuck body generally called a ball chuck). A tip member 4 is mounted in front of the barrel 1 by a method such as screwing, press-fitting, and bonding. Further, the tip member 4 may be integrated with the shaft cylinder 1. Further, a core protection tube 5 is attached to the tip of the tip member 4. Examples of the material of the core protection tube 5 include metal materials such as aluminum or its alloy, copper or its alloy, iron or its alloy, zinc or its alloy, magnesium or its alloy, ABS, AS, acrylic, polycarbonate, polypropylene, polyethylene, The material is not particularly limited as long as it can form a pipe, such as a thermoplastic resin such as polyester and polystyrene, a ceramic material such as alumina, zirconia, and clay, and a natural material such as wood and paper. Further, the outer and / or inner wall of the core protection tube 5 is previously coated with an electroplating method, an electroless plating method,
Nickel or chromium, a noble metal, a coating film, a printing pattern, or the like may be formed by printing. Examples of the method of mounting the core protection tube 5 include screwing, press-fitting, and adhesion, and are not particularly limited. Also, the core protection tube 5
May be integrated with the tip member 4. Also, reference numeral 6
Is a repelling member such as a coil spring that urges the lead-out mechanism such as the chuck body 3 rearward (upward in the figure).

Reference numeral 7 is a lead holding member. As specific examples of the resin used for the core holding member 7, a reaction curable resin, a thermosetting resin, and a thermoplastic resin can be used. Specific examples thereof include epoxy resin, urethane resin, acrylic melamine resin, acryl-silicone resin, acryl-urethane resin, unsaturated polyester resin, alkyd resin, silicone resin, vinyl chloride, vinyl acetate, and vinyl chloride-vinyl acetate copolymer. , Vinyl butyral resin, silicone rubber, urethane rubber, ethylene acrylic rubber, epichlorohydrin rubber, acrylic rubber, ethylene propylene rubber, chloroprene rubber, natural rubber, isoprene rubber, chlorinated polyethylene, nitrile rubber, styrene elastomer, olefin elastomer, ester Elastomers, ester elastomers, urethane elastomers and the like. Further, an ultraviolet curable resin may be used. Specific examples thereof include monofunctional monomers of acrylates and methacrylates having an acryloyl group at a terminal as a functional group, polyfunctional monomers, and photopolymerizable prepolymers. As a polymer,
Polyester acrylate, epoxy acrylate, polyurethane acrylate, polyether acrylate,
Melamine acrylate and alkyd acrylate are used. The monomer is not used alone, but is used in combination with a photopolymerizable prepolymer, and the photopolymerizable prepolymer is used alone or in combination of two or more.

Further, these resins may contain a powder, a foaming agent and the like. Specific examples of the powder include resin powders such as styrene, nylon, polyolefin, silicon, epoxy, and polymethyl methacrylate, and inorganic powders such as silica, alumina, and zirconia. In addition, composite powders obtained by coating these powders with powder coatings of acrylic, urethane, epoxy, etc., and resin powders using an automatic mortar, ball mill, jet mill, atomizer, hybridizer, etc. Examples thereof include those obtained by adsorbing or driving an inorganic powder smaller than the resin powder into the body. Further, the shape of the powder is not particularly limited, and a spherical shape, a plate shape, a needle shape, or the like can be used. One or more of these powders may be added. Further, by adding a powder having a melting point higher than the melting point of the resin, when a part of the resin is removed by a laser beam, irregularities due to the powder are formed, and the variation in the core diameter can be further absorbed.

As the foaming agent, a chemical foaming agent, a physical foaming agent, a heat-expandable microcapsule and the like are used. Specific examples of the chemical blowing agent include azo compounds, nitroso compounds, hydrazine derivatives, semicarbazide compounds, azide compounds, organic thermal decomposition type blowing agents such as triazole compounds, organic reaction type blowing agents such as isocyanate compounds, bicarbonates, Inorganic pyrolytic foaming agents such as carbonates, sulfites, and hydrides,
Inorganic reactive foaming agents such as sodium bicarbonate + acid, hydrogen peroxide + yeast, zinc powder + acid, and the like.
Specific examples of physical blowing agents include butane, pentane, hexane,
Examples include dichloroethane, dichloromethane, chlorofluorocarbon, air, carbon dioxide, and nitrogen gas. Specific examples of the heat-expandable microcapsules include a low-boiling hydrocarbon such as isobutane, pentane, petroleum ether, or hexane as a core substance, vinyldene chloride, acrylonitrile, acrylate,
Examples include microcapsules having a shell made of a thermoplastic resin made of a copolymer such as methacrylic acid ester.

The method of filling the core protection tube 5 with the resin is not particularly limited, as long as it is filled at normal temperature, normal pressure, heating, pressurizing, vacuum, or the like. In addition, the resin formed in the core protection tube 5 may be formed in a part of the entire core protection tube 5 or a part long enough to hold the core.

Next, a part of the filled resin is removed by a laser beam to complete the core holding member 7. The laser medium of the laser beam that can be used in the present invention is not particularly limited as long as it can melt and remove the resin by heat.
Specific examples thereof include solid-state lasers such as a ruby laser, a YAG laser, a glass laser, and a calcium tungstate laser, a He—Ne laser, an Ar laser, and a K laser.
gas laser such as r laser, CO ₂ laser, liquid laser such as selenium oxychloride laser, chelated laser, Ga-As laser, Ga-Sb laser, C
Examples include a semiconductor laser such as a d-S laser and a Zn-S laser, and an excimer laser. The holes may be formed by a laser processing machine or a laser marker using such a laser medium. The shape of the hole of the core holding member 7 is not particularly limited as long as it can hold the core, such as a cylindrical shape, a conical shape, a funnel shape, or a partially expanded shape. Further, the inner diameter (diameter of the hole formed by the laser) may be set so as to hold the core.

[0013]

<Example 1> Outer diameter 1.07 mm, inner diameter 0.7
A 6 mm long, 6.00 mm long stainless pipe was barrel polished and then degreased with a solvent. Next, a silicone resin (manufactured by Dow Corning Toray Silicone Co., Ltd., SE1701)
(W / C), a dedicated catalyst was added at 10 wt%, and after stirring, the inside of the stainless steel pipe was filled under pressure. Then, it was cured at 120 ° C. for 60 minutes. Then CO ₂
Using a laser processing machine (Mitsubishi Electric Co., Ltd., 2512HC), drilling was performed under the conditions of an output of 90 W and a processing time of 1 second, and a hole diameter of 0.5 was formed inside the core protection tube 5 of the mechanical pencil.
A 4 mm lead holding member 7 was formed to obtain a lead protection tube (FIG. 2).
reference).

<Embodiment 2> An outer diameter of 1.07 mm and an inner diameter of 0.
After a stainless steel pipe having a length of 76 mm and a length of 6.0 mm was barrel-polished, the stainless steel pipe was degreased with a solvent. Next, a silicone resin (manufactured by Dow Corning Toray Silicone Co., Ltd., SE1701)
(W / C), 10 wt% of a dedicated catalyst was added, and after stirring, the inside of the pipe was filled under pressure. Then 150
The composition was cured at 30 ° C. for 30 minutes. Next, using a CO ₂ laser marker (LP-200, manufactured by Sunkus Co., Ltd.), a spot diameter of 0.18 mm, an output of 6 W, and a scan speed of 5 were used.
A hole was drilled under the conditions of 00 mm / s and a processing time of 1 second, and the rear end hole diameter (reference numeral 8) was 0.54 mm and the front end hole diameter (reference numeral 9) was 0.52 inside the mechanical protection tube 5 of the mechanical pencil.
A core holding tube 7 was formed to obtain a core protection tube (see FIG. 3).

<Embodiment 3> An outer diameter of 1.06 mm and an inner diameter of 0.
After an iron pipe having a length of 77 mm and a length of 6.0 mm was barrel-polished, it was degreased with a solvent. Next, degreased by a known plating pretreatment method, and a 5 μm Ni plated film was formed by an electroless plating method. Next, urethane resin (LF, manufactured by Asahi Glass Co., Ltd.)
-105) was pressure-filled inside the pipe. Room temperature, 24
Cured under time conditions. Next, using a CO ₂ laser marker (LP-200, manufactured by Sunkus Co., Ltd.), a spot diameter of 0.18 mm, an output of 12 W, and a scan speed of 50 were used.
Drilling was performed under the conditions of 0 mm / s and a processing time of 0.3 second, followed by drilling under the conditions of a spot diameter of 0.18 mm, an output of 9 W, a scan speed of 500 mm / s, and a processing time of 0.3 second. .18 mm, output 6 W, scan speed 500 mm / s, processing time 0.3 seconds, drilled, rear end hole diameter (reference numeral 10) 0.54 mm, middle hole diameter inside core protection tube 5 of mechanical pencil (Reference numeral 11) 0.53 mm, tip hole diameter (reference numeral 12) 0.5
A 2 mm lead holding member 7 was formed to obtain a lead protection tube (FIG. 4).
reference).

<Embodiment 4> An outer diameter of 1.07 mm and an inner diameter of 0.
An ABS pipe having a length of 76 mm and a length of 6.0 mm was degreased with a solvent. Next, an elastic urethane paint (manufactured by Dainichi Seika Industry Co., Ltd., S
O-1501) was filled in a part of the inside of the pipe by a dipping method. Then, it was cured at 85 ° C. for 25 minutes. Next, using a CO ₂ laser marker (LP-200, manufactured by Sunkus Co., Ltd.), a spot diameter of 0.1
8mm, output 6W, scan speed 500mm / s,
Drilling was performed under a treatment time of 0.5 second, and a lead holding member 7 having a hole diameter of 0.52 mm was formed inside the lead protection tube 5 of the mechanical pencil to obtain a lead protection tube (see FIG. 5).

<Example 5> An outer diameter of 1.07 mm and an inner diameter of 0.
After a stainless steel pipe having a length of 76 mm and a length of 6.00 mm was barrel-polished, it was degreased with a solvent. Next, a silicone resin (manufactured by Dow Corning Toray Silicone Co., Ltd., SE170)
1W / C) with a dedicated catalyst of 10 wt% and a blowing agent (Expancel 551DU, manufactured by Nippon Philite Co., Ltd.)
-20) was added in an amount of 3 wt%, dispersed in a mortar, and then pressure-filled into the pipe. Thereafter, foaming and curing were performed at 150 ° C. for 10 minutes (reference numeral 13 is a void formed by foaming). Next, using a CO ₂ laser marker (LP-200, manufactured by Sunkus Co., Ltd.), a spot diameter of 0.18 mm, an output of 6 W, and a scan speed of 500 were used.
Drilling was performed under the conditions of mm / s and a processing time of 1 second, and a lead holding member 7 having a hole diameter of 0.54 mm was formed inside the lead protection tube 5 of the mechanical pencil to obtain a lead protection tube (see FIG. 6). .

<Embodiment 6> An outer diameter of 1.06 mm and an inner diameter of 0.
After a brass pipe having a length of 77 mm and a length of 6.0 mm was barrel-polished, it was degreased with a solvent. Next, degreased by a known plating pretreatment method, a 5 μm Ni plating film was formed by electroless plating, and then a 0.01 μm Cr plating film was formed by electroplating. Next, a silica powder 14 (manufactured by Fuji Silysia Chemical Ltd., Sylysia 7) was added to a thermosetting acrylic paint (Magiclon 1000, manufactured by Kansai Paint Co., Ltd.).
70) was added thereto, and the mixture was dispersed by a three-roll mill, and then the inside of the pipe was filled in a vacuum. Then 180
The composition was cured at 20 ° C. for 20 minutes. Next, using a CO ₂ laser beam machine (Mitsubishi Electric Co., Ltd., 2512HC), drilling was performed under the conditions of an output of 90 W and a processing time of 1 second, and a hole diameter of 0.54 mm was formed inside the core protection tube 5 of the mechanical pencil. Was formed to obtain a lead protection tube (see FIG. 7).

[0019]

According to the present invention, since a part of the resin is removed by a laser beam, the heat is less diffused, so that the precision and the properties of the resin (such as adhesion to the core protection tube) are not changed. Since a hole can be formed well, a core protection tube can be obtained in which the core does not drop by its own weight or rotate even when writing is performed on the core.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the core protection tube of the first embodiment.

FIG. 3 is a longitudinal sectional view of a core protection tube of a second embodiment.

FIG. 4 is a longitudinal sectional view of a core protection tube of a third embodiment.

FIG. 5 is a longitudinal sectional view of a core protection tube of a fourth embodiment.

FIG. 6 is a longitudinal sectional view of a core protection tube according to a fifth embodiment.

FIG. 7 is a longitudinal sectional view of a core protection tube of a sixth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Chuck ring 3 Chuck body 4 Tip member 5 Core protection tube 6 Repellent member 7 Core holding member

Claims (1)

[Claims] 1. A lead of a mechanical pencil, wherein a resin is filled in a protective tube of the lead of the mechanical pencil, and a part of the resin is removed by a laser beam to form a hole for feeding the lead. Manufacturing method of protective tube.