JP2002200880A - Manufacturing method of lead protective member of mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the lead protective member for a mechanical pencil, with which a residual lead can be effectively used, the strength of a lead can not be impaired, synthetic resin, rubber or the like can be easily filled in the lead protective member and, at the same time, the passing hole of the lead can be easily and highly accurately formed. SOLUTION: In the manufacturing method of the lead protective member of the mechanical pencil, in which an elastic resin with a longitudinal hole therein is provided near the top part of a pipe so as to have a lead protective member 6 by holding a lead lightly by means of the inner surface of the longitudinal hole in order to deliver the lead from the lead protective member 6 arranged at the tip of a barrel through the advance and retreat of a lead delivering mechanism arranged in the barrel, this manufacturing method includes a process for inserting a shaft body, the tip of which is made into a diametrically reducing part, into the pipe, a process for filling the liquid elastic resin between the diametrically reducing part of the shaft body and the inner surface of the pipe, a process for curing the liquid elastic resin and a process for pulling out the shaft body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a core protecting member in which an elastic resin having a longitudinal hole is provided near the tip of a pipe, and the core is lightly held by the inner surface of the longitudinal hole. Further, the present invention relates to a method for manufacturing a lead protection member of a mechanical pencil in which a lead is extended from a lead protection member disposed at a tip end of a barrel by moving forward and backward a lead feeding mechanism disposed in the barrel.

[0002]

2. Description of the Related Art Referring to FIG. This kind of mechanical pencil draws out a lead by using a lead feeding mechanism 4 including a chuck 2 such as a three-piece chuck and a ball chuck, and a chuck fastening member 3. When the lead is extended, the chuck 2 is advanced against a repelling force of an elastic member (not shown) in a state where the core L is gripped by the chuck member 3, and after being advanced by a predetermined distance, the chuck member is moved forward. 3 (the end member 5 fixed to the barrel 1 in the figure).
Then, when the chuck 2 is further advanced, the chuck 2 is opened. In this state, when the movement of the chuck 2 is released, the chuck 2 is brought into contact with the chuck tightening member 3 by the elastic force of the elastic member. The lead L is retracted until it is engaged. During this time, the lead L is held by the detent member S formed of rubber or the like, and the lead is regulated and the lead is fed out. By repeating this operation, the core L projects from the core protection member 6 at the tip of the barrel 1 (tip member 5). However, when the lead is shortened by writing, the lead cannot be held by the chuck 2, and the lead remains between the leading end of the chuck 2 and the lead protecting member 6. Since the remaining core (hereinafter, referred to as “remaining core”) L is only lightly held by the detent member S, the writing feeling is deteriorated. Therefore, the residual core is generally extruded and discharged by a subsequent core or pulled out by a finger or the like and discarded. Further, when the residual core is removed from the detent member S, the above-described phenomenon is remarkably observed, and the residual core may fall due to its own weight.

[0003] Therefore, in order to make effective use of this residual core, proposals have been made for a core protecting member. For example,
A projection is formed on the inner surface of the lead protection member, and the projection is cut into the surface of the remnant core to prevent the remnant core from falling due to its own weight (Japanese Patent Application Laid-Open Nos. 56-18898 and 58-20).
No. 3099). Further, an elastic thin film made of rubber or the like is integrally laminated on the inner surface of the core protecting member, and the elastic thin film increases the frictional resistance with the residual core and prevents the residual core from falling due to its own weight (Japanese Utility Model Publication No. 58-32959). Gazette) is known.

[0004]

However, these prior art lead protection members have various problems. In the former, there is a quality problem that the protrusions are cut into the remnant core, preventing the fall when writing the remnant core, causing the surface of the core to be scratched by the protrusion and significantly impairing the strength of the fine core. was there. The latter does not have such a problem, but has a problem that it is difficult to form an elastic thin film of good quality in manufacturing. This is because, in the latter, the method of forming an elastic film in the lead protection member employs a method of press-filling synthetic resin or rubber or the like into the lead protection member and then forming a hole through which the lead passes. Over the entire length of the protective member,
This is because the hole diameter is varied or distorted due to being filled with a synthetic resin, rubber, or the like. Furthermore, since the inner diameter of the lead protection member of the mechanical pencil is small, it is necessary to press-fit synthetic resin, rubber, etc. into the lead protection member, and to form the passage hole of the lead itself, which requires high precision technology. Required expensive manufacturing equipment and advanced production techniques. That is, the latter technique has a problem that it is difficult to implement. Therefore, it is an object of the present invention to provide a method for manufacturing a lead protecting member of a mechanical pencil, in which a synthetic resin, rubber, or the like can be easily filled in the lead protecting member of the mechanical pencil, and the passage hole of the lead can be easily formed with high precision. And

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a lead protection member in which an elastic resin having a longitudinal hole is disposed near a pipe tip, and a core is lightly held by an inner surface of the longitudinal hole. In a method for manufacturing a lead protecting member of a mechanical pencil, a lead is drawn out from a lead protecting member disposed at the tip of the barrel by moving forward and backward a lead feeding mechanism disposed in the barrel. The method includes the steps of inserting a shaft having a reduced diameter portion at the end into a pipe, filling a liquid elastic resin between the reduced diameter portion of the shaft and the inner surface of the pipe, and curing the liquid elastic resin. A first aspect of the present invention is a method of manufacturing a lead protecting member of a mechanical pencil, comprising a step of extracting the shaft body, and disposing an elastic resin having a longitudinal hole near a pipe tip. , The inner surface of the longitudinal hole It has a lead protection member that holds the lead lighter, and the lead-out mechanism that is placed inside the barrel is advanced and retracted so that the lead is drawn out from the lead protection member that is placed at the tip of the barrel. In the method for manufacturing a lead protecting member of a pencil, at least a step of inserting a shaft into a pipe having an enlarged inner diameter at the tip end, and a step of filling a liquid elastic resin between the shaft and the pipe enlarged diameter portion, A method of manufacturing a lead protecting member of a mechanical pencil, which includes a step of curing a liquid elastic resin and a step of pulling out the shaft body, is provided with a longitudinal hole near the tip of the pipe. The core is provided with an elastic resin, and has a core protecting member for holding the core lightly by the inner surface of the longitudinal hole. Ahead of In the method for manufacturing a lead protecting member of a mechanical pencil, which is extended from a lead protecting member disposed in the pipe, the manufacturing method includes a step of inserting a shaft body so that a shaft body tip stops near a pipe tip section; Filling a liquid elastic resin into the
A step of curing the liquid elastic resin, a step of pulling out the shaft body, and a step of forming a hole in the longitudinal direction by removing a part of the elastic resin, The manufacturing method is a third aspect.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is an example of a longitudinal sectional view of a mechanical pencil using the lead protection member obtained according to the present invention, and FIG. 3 is an example of a longitudinal sectional view of a main part thereof. 2 and 3, reference numeral 1 denotes a mechanical cylinder of a mechanical pencil. Inside the cylindrical cylinder 1, a chuck 2 such as a three-piece chuck and a ball chuck (a three-piece chuck in the figures) and a chuck tightener are provided. A centering mechanism 4 composed of a member 3 (a ring in the figure, a ball is used in the case of a ball chuck) is arranged.
Reference numeral 5 denotes a tip member fixed to the barrel 1, but the tip member 5 may be integral with the barrel 1. Further, the tip member 5
The lead protection member 6 is fixed to the tip of the. Reference numeral 7 denotes a repelling member such as a coil spring for urging the lead-out mechanism 4 rearward (upward in the drawing). Therefore, the center feeding mechanism 4 can advance and retreat in the longitudinal direction. still,
In the drawing, an example is shown in which the center detent member used in the conventional mechanical pencil is removed, but the center detent member may be disposed behind the core protection member as in the conventional case. The above configuration is the same as the basic configuration of a conventional general rear end knock mechanical pencil. The present invention can also be used in mechanical pencils having a conventionally known structure such as a tip knock type, a rotary knock type, a side slide type, and a center-bent knock type.

A feature of the present invention resides in a method of manufacturing the lead protection member 6. FIG. 4 is an example of a vertical cross-sectional view of the lead protection member obtained by the present invention, and FIG. 5 is a cross-sectional view taken along line AA ′ of FIG.

Accordingly, the lead protection member 6 will be described in detail.
A core holding member 8 made of an elastic resin for holding the core is formed in the vicinity of the end of the pipe inside the core protection member 6. The core can also hold the core.

The core protecting member 6 includes a step of inserting a shaft into a pipe, a step of filling a liquid elastic resin into the pipe, a step of curing the resin, and a step of pulling out the shaft. Accordingly, it is obtained by a step of removing a part of the elastic resin, and will be described below.

The material of the core protecting member 6 is a metal material 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. The material is not particularly limited as long as it can form the pipe shape, such as thermoplastic resins such as polyethylene, polyester, and polystyrene, ceramic materials such as alumina, zirconia, and clay, and natural materials such as wood. Alternatively, nickel or chromium, a noble metal, a coating film, a printing pattern, or the like may be formed on the outer wall and / or the inner wall of the core protection member 6 in advance by electroplating, electroless plating, painting, or printing.

In the case where a core protection member having an enlarged inner diameter at least at the distal end is used, it may be inserted until the distal end of the shaft reaches the end of the pipe. Examples of the enlarged diameter shape include a tapered shape from the rear end to the front end and a step-like shape from the rear end to the front end, but are not particularly limited. The shape of the lead protection member in the radial direction is circular, elliptical, square,
Examples include a star-shaped or petal-shaped one, a slit formed in the inner surface in the longitudinal direction, and a shape provided with a rib in the longitudinal direction, but are not particularly limited.

The material of the shaft body to be inserted into the pipe includes:
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,
There is no particular limitation as long as the shaft can be formed, such as a thermoplastic resin such as polycarbonate, polypropylene, polyethylene, polyester, and polystyrene, a ceramic material such as alumina, zirconia, and clay, and a natural material such as wood. In consideration of the step of pulling out the shaft after the elastic resin is cured, it is desirable to apply a lubricant, a surfactant or the like so that the resin does not adhere to the surface of the shaft.

When using a shaft having a reduced diameter portion at the tip, the shaft may be inserted until the tip of the shaft reaches the end of the pipe. Examples of the reduced diameter shape include a tapered shape from the rear end to the front end and a step-like shape from the rear end to the front end, but are not particularly limited. The shape of the shaft body with respect to the radial direction includes a circular shape, an elliptical shape, a square shape, a star shape, a petal shape, a shape in which a longitudinal slit is formed on an inner surface, a shape in which a rib is provided in a longitudinal direction, and the like. There is no particular limitation.

As specific examples of the elastic resin used for the core holding member 8, 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,
Examples thereof include nitrile rubber, styrene-based elastomer, olefin-based elastomer, ester-based elastomer, and urethane-based elastomer. 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 the 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. This elastic resin is liquid at the time of filling. Further, these resins may contain a foaming agent, a powder or the like.

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 a mixture of sodium bicarbonate and acid, a mixture of hydrogen peroxide and yeast, and a mixture of zinc powder and acid are exemplified. Specific examples of the physical foaming agent include butane, pentane, hexane, dichloroethane, dichloromethane, freon, air, carbon dioxide, and nitrogen gas. Specific examples of the heat-expandable microcapsules are thermoplastics composed of a copolymer such as vinyldene chloride, acrylonitrile, acrylic acid ester, methacrylic acid ester and the like, with a low boiling point hydrocarbon such as isobutane, pentane, petroleum ether, and hexane as a core substance. Microcapsules having a resin as a shell are exemplified.

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, those powders, acrylic, urethane, composite powder coated with an epoxy-based powder coating, etc., furthermore, an automatic mortar,
Examples thereof include those obtained by adsorbing or driving an inorganic powder smaller than the resin powder into the resin powder using a ball mill, a jet mill, an atomizer, a hybridizer, or the like. 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. Also, 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 the laser beam, irregularities due to the powder are formed, and the variation in the core diameter can be further absorbed.

The method of filling the core protective member 6 with the elastic resin may be at room temperature, normal pressure, heating, pressurizing, vacuum, or the like, and is not particularly limited. When filling, use a shaft with a reduced diameter portion at the tip as the shaft, and if the tip of the shaft is inserted until it reaches the end of the pipe, the gap between the shaft reduced diameter portion and the pipe inner surface Is filled with a liquid elastic resin. In addition, when a shaft body having no reduced diameter portion at the tip is used, the shaft body is inserted near the pipe tip so that the shaft body tip stops, and is surrounded by the pipe inner wall and the shaft body tip. The filled space is filled with the liquid elastic resin. Even when a shaft having a reduced diameter portion at the tip is used, the shaft is inserted so that the tip of the shaft stops near the tip of the pipe, and the shaft is surrounded by the inner wall of the pipe and the tip of the shaft. A liquid elastic resin can also be filled between the space provided and the reduced diameter portion of the shaft body and the inner surface of the pipe.

The method of curing the filled elastic resin includes room temperature standing, heat treatment, pressure treatment, ultraviolet irradiation, and electron beam irradiation. The method is appropriately selected according to the curing conditions of the elastic resin to be used. do it. By this curing step, the liquid elastic resin becomes a solid elastic resin and is fixed in the pipe.

When the filled and cured resin has no longitudinal hole, that is, when the shaft is inserted so that the tip of the shaft stops near the tip of the pipe, the longitudinal hole is formed. It is necessary to remove a part of the resin filled in the resin. In addition, even when a longitudinal hole is formed in the filled and cured resin, a part of the filled resin for deforming the shape of the longitudinal hole can be removed. In removing part of the filled resin, it is preferable to use a laser beam. When the hole 9 is formed in the longitudinal direction by removing with a laser beam, the laser medium of the laser beam used is not particularly limited as long as the resin can be melted by heat and removed. Specific examples are ruby laser, YAG laser,
Glass laser, solid laser such as calcium tungstate laser, He-Ne laser, Ar laser,
Gas lasers such as Kr laser and CO ₂ laser, liquid lasers such as selenium oxychloride laser and chelated laser, Ga-As laser, Ga-Sb laser, Cd
Semiconductor lasers such as -S laser, Zn-S laser,
Excimer laser and the like can be mentioned. The holes may be formed by a laser processing machine or a laser marker using such a laser medium.

The cross-sectional shape of the core holding member 8 is circular, elliptical,
Examples include, but are not limited to, a square, a star, a petal, a slit formed in the inner surface in a longitudinal direction, and a rib provided in a longitudinal direction. As the vertical cross-sectional shape, as shown in FIG. 4, a shape having the same thickness, a tapered shape from the rear end to the front end as shown in FIG.
As shown in FIG. 7, various shapes such as a step-like shape from the rear end to the front end can be adopted. However, the shape is not particularly limited as long as it can be created by adjusting the shape of the shaft inserted into the pipe and the output and focus of the laser beam.

In this method, the shaft is inserted into the lead protecting member 6, filled with an elastic resin to be the lead holding member 8, and after the resin is cured, the shaft is pulled out. When the tip member 5 is formed separately from the barrel 1, the core protection member 6 is attached to the tip of the tip member 5 by press-fitting or insert molding, and then the shaft protection member 6 is inserted into the core protection member 6, and the elastic resin is formed. Filling, curing of the resin, and pulling out of the shaft may be performed. The hole 9 of the lead holding member 8 of the lead protection member 6
The extended core will be placed on the inner surface of the
At this time, since the core needs to be held lightly by the inner surface of the hole 9 of the core holding member 8, the core holding member 8 needs to have elasticity in the radial direction. Therefore, if the resin used for the core holding member 8 does not have elasticity in the radial direction, it is necessary to add an additive to impart elasticity. The holding force of the lead by the lead holding member 8 may be such that the remaining lead does not drop by its own weight, but is preferably set to 10 g to 100 g in the lead passing direction. In addition, when the holding force is 35 g to 100 g, an effect that the rotation of the lead generated at the time of writing with the residual lead can be suppressed can be expected.

Further, the leading end of the lead protection member 6 may be plastically deformed (see FIG. 9). Further, a part of the elastic resin may be removed after the plastic deformation of the tip (see FIG. 10).

[0023]

<Example 1> Outer diameter 1.07 mm, inner diameter 0.7
After a stainless steel pipe having a length of 6 mm and a length of 6.0 mm was barrel-polished, the pipe was degreased with a solvent. Next, the outer diameter of the portion from the tip to 2 mm is 0.57 mm, and the outer diameter after 2 mm is 0.1 mm.
After applying a surfactant to a 75 mm stainless steel shaft, the tip was aligned and inserted into a stainless steel pipe. Silicone resin (GE Toshiba Silicone Co., Ltd., T
SE3221) was pressure-filled into the gap formed between the stainless steel pipe and the tip of the stainless steel shaft. Then, it was cured at 150 ° C. for 30 minutes. Next, the stainless steel shaft was pulled out to form a core protecting member as shown in FIG. Next, the tip member of a mechanical pencil (PG305D, manufactured by Pentel Co., Ltd.) is removed, and this core protecting member is press-fitted and fixed to another tip member (manufactured by Pentel, Inc., A125). I got

Example 2 A stainless steel pipe having an outer diameter of 1.07 mm, an inner diameter of 0.76 mm from the tip to 2 mm, an inner diameter of 0.58 mm after 2 mm, and a length of 6.0 mm was barrel-polished. Thereafter, the solvent was degreased. Next, a surfactant was applied to a stainless steel shaft having an outer diameter of 0.57 mm, and then inserted into a stainless steel pipe with its tip portion aligned. Silicone resin (GE Toshiba Silicone Co., Ltd.
TSE3221) was pressure-filled into the gap formed between the stainless steel pipe and the tip of the stainless steel shaft. Then, it was cured at 150 ° C. for 30 minutes. Next, the stainless steel shaft was pulled out to form a core protecting member as shown in FIG. Next, the tip member of a mechanical pencil (PG305D, manufactured by Pentel Co., Ltd.) is removed, and this core protecting member is press-fitted and fixed to another tip member (manufactured by Pentel, Inc., A125). I got

<Embodiment 3> 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 pipe was degreased with a solvent. Next, after applying a surfactant to a tapered stainless steel shaft having an outer diameter of 0.57 mm and an outer diameter of 2 mm from the tip and an outer diameter of 0.75 mm, the tip is fitted into a stainless steel pipe. Inserted. Next, silicone resin (Toray Dow Corning
10 wt% of a dedicated catalyst was added to SE1701W / C (manufactured by Silicone Co., Ltd.), and after stirring, the inside of the pipe was filled under pressure. Then, it was cured at 150 ° C. for 30 minutes. Next, the stainless steel shaft was pulled out to form a core protection member as shown in FIG. Next, the tip member of the mechanical pencil (PG305D, manufactured by Pentel Co., Ltd.) is removed, and the core protecting member is press-fitted and fixed to another tip member (manufactured by Pentel, Inc., A125). I got

<Embodiment 4> An outer diameter of 1.06 mm and an inner diameter of 0.
After an iron pipe having a length of 76 mm and a length of 6.0 mm was barrel-polished, it was degreased with a solvent. Next, after applying a surfactant to a stainless steel shaft having an outer diameter of 0.75 mm, it was inserted into a stainless steel pipe while leaving 2 mm from the tip. Silicone resin (GE Toshiba Silicone Co., Ltd., TSE3221)
Was pressurized and filled into a space surrounded by the inner surface of the iron pipe and the tip of the stainless steel shaft. Then 150
After curing at 30 ° C. for 30 minutes, the stainless steel shaft was pulled out. Next, a CO ₂ laser processing machine (manufactured by Mitsubishi Electric Corporation, oscillator ML5036D, processing table ML2)
512HDII, processing lens f 7.5 inches, processing nozzle # 2.0), output 200W, processing time 0.5
Drilling was performed under the condition of seconds to form a core protection member. Next, a mechanical pencil (PG305, manufactured by Pentel Co., Ltd.)
D) Remove the tip member and replace it with another tip member (Pentel Corporation)
Manufactured by the company, A125 tip member) was press-fitted and fixed to obtain a mechanical pencil. The tip member of a mechanical pencil (PG305D, manufactured by Pentel Co., Ltd.) was removed, and the core protecting member was press-fitted and fixed to another tip member (manufactured by Pentel, Inc., A125) to obtain a mechanical pencil. .

<Example 5> An outer diameter of 1.06 mm and an inner diameter of 0.
After an iron pipe having a length of 76 mm and a length of 6.0 mm was barrel-polished, it was degreased with a solvent. Next, the outer diameter of the portion from the tip to 1 mm is 0.62 mm, the outer diameter from 1 mm to 2 mm is 0.68 mm, and the outer diameter from 2 mm is 0.75 mm. After applying the activator, the tip was inserted into a stainless steel pipe. Silicone resin (GE Toshiba Silicone Co., Ltd., T
SE3221) was pressure-filled into the gap formed between the iron pipe and the tip of the stainless steel shaft. Then, it was cured at 150 ° C. for 30 minutes. Next, the stainless steel shaft was pulled out to form a lead protection member as shown in FIG. Next, use a mechanical pencil (Pentel Corporation)
PG305D) was removed, and the lead protection member was press-fitted and fixed to another tip member (A125 tip member manufactured by Pentel Co., Ltd.) to obtain a mechanical pencil. The tip member of a mechanical pencil (PG305D, manufactured by Pentel Co., Ltd.) was removed, and the lead protection member was press-fitted and fixed to another tip member (manufactured by Pentel, Inc., A125) to obtain a mechanical pencil. .

[0028]

According to the present invention, the liquid elastic resin is filled in the space between the inner surface of the pipe and the outer wall of the shaft inserted into the pipe, so that the elastic resin layer can be easily formed on the inner surface of the pipe.
Further, since the elastic resin is formed only up to the insertion position of the tip of the shaft, the elastic resin layer is formed only near the tip of the pipe. The holes formed in the elastic resin layer can be formed with high precision because the entire length of the elastic resin layer is short, not only when the hole is formed by the reduced diameter portion of the shaft body but also when post-processing is performed. The use of a shaft having a reduced diameter portion at the tip also has the effect that the cross-sectional shape of the hole can be easily set. In addition, the mechanical pencil using the lead protection member obtained by the present invention does not damage the lead surface by protrusions in order to prevent falling, so that there is also a problem that the strength of the fine lead is significantly impaired. do not do.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a conventional mechanical pencil.

FIG. 2 is a longitudinal sectional view of a mechanical pencil using a lead protection tube obtained according to the present invention.

FIG. 3 is a longitudinal sectional view of a main part of FIG. 2;

FIG. 4 is a longitudinal sectional view of an example of a core protection member using a core protection tube obtained according to the present invention.

FIG. 5 is a cross-sectional view of an example of a core protection member using a core protection tube obtained according to the present invention.

FIG. 6 is a longitudinal sectional view of an example of a core protection member using a core protection tube obtained according to the present invention.

FIG. 7 is a longitudinal sectional view of an example of a core protection member using the core protection tube obtained according to the present invention.

FIG. 8 is a longitudinal sectional view of an example of a core protection member using the core protection tube obtained according to the present invention.

FIG. 9 is a longitudinal sectional view of an example of a core protection member using a core protection tube obtained according to the present invention.

FIG. 10 is a longitudinal sectional view of an example of a core protection member using the core protection tube obtained according to the present invention.

[Explanation of symbols]

 L core (remaining core) S detent member 1 barrel 2 chuck 3 chuck tightening member 4 core feeding mechanism 5 tip member 5a stepped portion 6 core protection member 7 repellent member 8 core holding member 9 hole 10 core tank 11 knock 12 axis Body 13 Plastic deformation part 14 Partially removed part

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[Procedure amendment]

[Submission date] January 5, 2001 (2001.1.5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Takeshi Nagaki 4-1-8 Yoshimachi, Soka City, Saitama Prefecture Pentel Co., Ltd. Grass Processing Plant (72) Inventor Tsuruo Nakayama 4-1-8 Yoshimachi, Soka City, Saitama Prefecture Pentel Co., Ltd. Grass Processing Plant F-term (reference) 2C353 FA04 FC11 FE03 FE05 FG02 HA06 MC04

Claims (4)

[Claims] 1. A core protection member provided with an elastic resin having a longitudinal hole provided in the vicinity of a pipe tip and having a core held lightly by an inner surface of the longitudinal hole. In a method for manufacturing a lead protecting member of a mechanical pencil, in which a lead is drawn out from a lead protecting member placed at the tip of a barrel by moving the placed lead feeding mechanism forward and backward, the manufacturing method includes the step of reducing the tip with a reduced diameter portion. Inserting the shaft into the pipe, filling the liquid elastic resin between the shaft reduced diameter portion and the pipe inner surface, curing the liquid elastic resin, and pulling out the shaft And a method of manufacturing a lead protecting member of a mechanical pencil. 2. A core protecting member which is provided with an elastic resin having a longitudinal hole in the vicinity of a pipe tip, and which holds the core lightly by the inner surface of the longitudinal hole. The method for manufacturing a lead protection member of a mechanical pencil, in which the lead is drawn out from the lead protection member disposed at the tip of the barrel by moving the lead delivery mechanism forward and backward, the manufacturing method includes at least the inner diameter of the tip part. Inserting the shaft into the pipe whose diameter has been increased, filling the liquid elastic resin between the shaft and the pipe enlarged portion, curing the liquid elastic resin, and pulling out the shaft A method for manufacturing a lead protecting member of a mechanical pencil, comprising: 3. A core protection member provided with an elastic resin having a longitudinal hole provided in the vicinity of a pipe tip and holding a core lightly by an inner surface of the longitudinal hole. In the method of manufacturing a lead protection member of a mechanical pencil in which the lead is extended from the lead protection member disposed at the tip of the barrel by retracting the placed lead feeding mechanism forward and backward, the manufacturing method includes a pipe tip vicinity. Inserting the shaft so that the shaft end stops, filling the liquid elastic resin into the pipe tip, curing the liquid elastic resin, extracting the shaft, and removing the elastic resin. Forming a hole in the longitudinal direction by removing a part of the core protecting member of the mechanical pencil. 4. The method according to claim 32, wherein a laser beam is used to remove a part of the elastic resin.