JP2003226092A - Lead protection member of propelling pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To absorb the irregularity of lead holding force by providing a space for absorbing the irregularity of the diameter of a lead in the lead protection member of a propelling pencil having at least an elastic resin body having a profile cross-sectional shape provided to the inner surface thereof. <P>SOLUTION: In the lead protection member of the propelling pencil having at least the elastic resin body having a through-hole formed to the inner surface of the lead protection member, the through-hole formed to the elastic resin body has a profile cross-sectional shape and the lead (JIS S 6005) for the propelling pencil is brought into contact with the inner surface of the elastic resin body at least at two or mode points when the lead pierces the through-hole and a space is provided between the lead for the propelling pencil and the elastic resin body. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lead protection member for a mechanical pencil.

[0002]

2. Description of the Related Art A description will be given with reference to FIG. This type of mechanical pencil uses a lead-out mechanism 4 composed of a chuck 2 such as a three-piece chuck or a ball chuck, and a chuck fastening member 3, and the lead-out mechanism is as follows. First, the chuck 2 is tightened by the chuck tightening member 3 to hold the core L. Next, a pressing force is applied to the chuck 2 to move it forward against the elastic force of a repellent member (not shown), and the chuck fastening member 3 is attached to the barrel 1 by a step 5a of the tip member 5a. To the position where it abuts. When the chuck 2 is further advanced, the chuck tightening member 3 is disengaged from the chuck 2, so that the chuck 2 is opened. At this time, when the pressing force applied to the chuck 2 is released, the chuck 2 retracts to the position where it is engaged with the chuck tightening member 3 due to the elastic force of the elastic member. However, at this time, the lead L is held by the detent member S made of rubber or the like and remains at the position moved by the forward movement of the chuck. Therefore, when the chuck 2 retracts and engages with the chuck tightening member 3 to grip the lead, the gripping position is behind the above position. Then, by repeating this operation, the lead L can be fed forward. By the way, when the core is shortened by writing, the core may not be grasped by the chuck 2. The lead L separated from the chuck 2 remains between the tip of the chuck 2 and the lead protecting member 6. This remaining core (hereinafter referred to as "remaining core") L
Is only lightly held by the detent member S, so that the writing feeling becomes poor. The diameter of the mechanical pencil lead (JIS S 6005) varies (for example, 0.55 mm to 0.58 mm for a nominal diameter of 0.5). In some cases, the detent member S could not be held, and the residual core would drop due to its own weight. Therefore, the residual core is
Generally, it is pushed out by a trailing lead and discharged, or pulled out by a finger or the like and discarded. Further, if the residual core is detached from the detent member S, the above-mentioned phenomenon is noticeable, and in some cases, the core may fall due to its own weight regardless of the diameter of the core.

Therefore, in order to effectively utilize this residual core,
Proposals have been made for detent members, lead protection members or lead protection tubes. For example, a protrusion is formed on the inner surface of the detent member to absorb the variation in the diameter of the core (see Patent Document 1), or an elastic thin film made of rubber or the like is integrally laminated on the inner surface of the core protection tube. There is known a thin film that increases frictional resistance with the remnant core and prevents the remnant core from falling due to its own weight (see Patent Document 2).

[0004]

[Patent Document 1] Japanese Utility Model Publication No. 55-23737 (1st
(Figure, Figure 2)

[Patent Document 2] Japanese Utility Model Publication No. 58-32959 (claim 1 for utility model registration, column 4, line 25 to column 30, line 30)

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
By using the detent member having the protrusion formed on the inner surface, it is possible to absorb the variation in the diameter of the core and prevent the residual core from falling by its own weight. However, there is a problem in that the residual core removed from the detent member cannot prevent the weight from falling. On the other hand, in Patent Document 2, although the residual core can be effectively used by using the core protection member in which the elastic thin film is integrally laminated on the inner surface, the pressure for holding the core (hereinafter, “ There is a case in which the core does not come out. The present invention relates to a lead protection member for a mechanical pencil having an elastic resin body having an irregular cross-sectional shape at least on the inner surface thereof, and by providing a space for absorbing the variation in the diameter of the lead, a core for absorbing the variation in the core holding force. An object is to provide a protective member.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is a lead protection member for a mechanical pencil in which an elastic resin body having at least a through hole is formed inside a lead protection member. In, when the through-hole formed in the elastic resin body has an irregular cross-sectional shape and penetrates the mechanical pencil lead (JIS S 6005),
A lead protecting member for a mechanical pencil, wherein the lead for the mechanical pencil is in contact with at least two points on the inner surface of the elastic resin layer and has a space between the lead for the mechanical pencil and the elastic resin body. It is what

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. The same reference numerals are used for the same parts in the respective embodiments. FIG. 2 is an example of a partial cross-sectional schematic view of a mechanical pencil equipped with a lead protection member according to the present invention. Reference numeral 1 is a mechanical pencil barrel, and a chuck 2 such as a three-piece chuck or a ball chuck (the figure shows a three-piece chuck) and a chuck tightening member 3 are provided in the barrel 1. (The drawing shows a ring, but when a so-called ball chuck is used as a chuck, a ball is used) and a lead-out mechanism 4 is arranged. Reference numeral 5 is a tip member fixed to the barrel 1, but the tip member 5 may be integral with the barrel. Further, a lead protection member 6 is fixed to the tip of the tip member 5. The lead protection member 6 may be integrated with the tip member 5. Reference numeral 7 is an elastic member such as a coil spring that biases the lead-out mechanism 4 backward (upward in the drawing). Therefore, the lead-out mechanism 4 can move forward and backward in the longitudinal direction. In the figure, an example in which the lead detent member used in the conventional mechanical pencil is removed is shown, but like the conventional mechanical pencil, the lead detent member may be arranged behind the lead protective member. .

The above structure is the same as the basic structure of a conventional general mechanical pencil. The features of the present invention are:
It is in the core protection member.

Example 1 FIG. 3 is a schematic cross-sectional view of a lead protection member according to Example 1. The core protection member 6 is an elastic resin body 8 that holds the core inside.
And the metal layer 9 is formed on the outside of the elastic resin body 8. A through hole is formed in the elastic resin body 8, and the core L slides in the through hole and is held by the elastic resin body 8 not only when it is long but also in the residual core. .

The cross-sectional shape of the through hole of the elastic resin body 8 is particularly important in the present invention, and is elliptical (FIG. 4), polygonal (FIG. 5), uneven shape or slit shape (FIG. 6), rib shape ( 7) and the like, and there is no particular limitation as long as it is an irregular shape other than a circular shape. However, in order to absorb the variation in the diameter of the core, the minimum value of the diameter of the core of the mechanical pencil defined by JIS S 6005 (the nominal diameter is 0.
In No. 5, when it penetrates 0.55 mm), it is necessary to contact at least a part of the inner surface of the elastic resin body at two or more points to have a space. By having this space, even when the maximum value of the diameter of the core (0.58 mm in the case of 0.5) is penetrated, the contact portion is deformed and the variation in the core holding force can be absorbed. The cross-sectional area of the minimum diameter of the core (0.55 mm when the nominal diameter is 0.5) is X,
The relational expression when the cross-sectional area of the space (the cross-sectional area of the space formed when the minimum diameter of the core is penetrated) is Y is 0.09.
By satisfying ≦ Y / X ≦ 1.12, JIS S 6
All of the mechanical pencil leads specified in 005 (nominal diameter 0.3, nominal diameter 0.5, nominal diameter 0.7,
Nominal diameter 0.9, nominal diameter 2.0) and color cores for mechanical pencils are available. Also, JIS
The diameter of the lead is 0.275 even in those other than the lead for pencil and the color lead defined in S 6005.
It is possible to cope with it in the range of mm to 2.07 mm.

In the present invention, the sectional area of the space is important.
An example of a nominal diameter of 0.5 will be described in detail. JIS
Nominal diameter of 0.5, as determined by S 6005
Has a minimum value of 0.55 mm and a cross-sectional area of 0.238 m.
m²Is. On the other hand, the maximum diameter is 0.58 mm.
Cross section is 0.264 mm²Becomes 0.55 mm core
At least part of the inner surface of the elastic resin body
It is necessary to contact at least two points and to have a space. Also
The space also exists when the 0.58 mm core is penetrated.
Therefore, the cross-sectional area of the space is
0.58 mm core cross-sectional area and 0.55 mm core cross-sectional area
More than the difference is required. That is, the cross-sectional area of the smallest space
Is 0.264 (mm²) -0.238 (mm²) = 0.
026 (mm²). The minimum space cross section
The minimum core cross-sectional area ratio is 0.026 (mm²)
/ 0.238 (mm²) = 0.11. Also, Shah
Contains two or more lead for pencil (subsequent lead, broken lead, etc.)
If there is a space that can be knocked, the core will not come out even when knocked
May occur. Therefore, the cross-sectional area of the largest space
Is the maximum core cross-sectional area (0.264 mm²). You
That is, the minimum core cross-sectional area for the maximum space cross-sectional area
Is 0.264 (mm ²) /0.238 (mm²)
= 1.12. From the above, the relational expression of Y / X
By 0.11 ≦ Y / X ≦ 1.12,
Even when the maximum diameter (0.58 mm) is penetrated
There is a space and there is a problem that two or more cores enter and the core does not come out
Does not live

Further, when the core is scraped by the frictional force generated when the core is paid out, core scraps are accumulated in the core protection member, and the core scraps are attached to the surface of the elastic thin film and laminated, so that the elastic thin film is in a state of being thickened. Since the pressure for holding the core may increase, a deformed shape in which core scrap is less likely to be stacked is desirable.

The elastic resin body 8 may be formed in a pipe and / or tube shape, and its external shape is not particularly limited. Specific examples of the molding method include compression molding, direct pressure molding, transfer molding, injection molding, extrusion molding, inflation molding, thermoforming such as vacuum molding and pressure molding, foam molding, powder molding, reaction molding (RIM), firing. Examples include, but are not limited to, binding forming and casting.

The resin used for the elastic resin body 8 is not particularly limited as long as it has elasticity. However, the type A durometer hardness (JIS K 6253) is preferably 10 to 90 in order to absorb variations in the diameter of the core. If it is less than 10, it is difficult to maintain the shape, and 9
This is because if the value exceeds 0, the contact portion is less likely to be deformed, and the variation in the diameter of the core cannot be absorbed. Specific examples of the elastic resin include acrylic resin, silicone resin, fluorine resin, vinyl chloride, urethane resin, polyurethane resin, polyethylene resin, dimethyl silicone rubber, methyl vinyl silicone rubber, methylphenyl vinyl silicone rubber, methyl fluoroalkyl. Type silicone rubber (fluorosilicone), fluoro-dimethyl copolymer silicone, urethane rubber, ethylene acrylic rubber, epichlorohydrin rubber, acrylic rubber, ethylene propylene rubber, chloroprene rubber, natural rubber, isoprene rubber, chlorinated polyethylene, nitrile rubber, styrene type Examples thereof include elastomers, olefin elastomers, ester elastomers, urethane elastomers and the like. These elastic resins may be one kind or a mixture of two or more kinds. In particular, by using the elastic resin having excellent oil resistance, the elastic resin body 8 hardly absorbs the nonpolar organic compound even when the core containing the nonpolar organic compound slides in the through hole, and the elastic resin Swelling of the body 8 is reduced. As a result, the increase in the core holding force is suppressed. Specific examples thereof include nitrile rubber, silicone rubber, and derivatives thereof, and of these, methylfluoroalkyl-based silicone rubber (fluorosilicone) and fluoro-dimethyl copolymerized silicone rubber are preferable.

Further, these elastic resins may contain powders, foaming agents, conductive fine particles or coloring agents.
Specific examples of the powder include resin powders such as styrene, nylon, polyolefin, silicon, epoxy and polymethylmethacrylate, and inorganic powders such as silica, alumina and zirconia. Also, in those powders,
A composite powder coated with a powder coating of acrylic, urethane, epoxy, etc., as well as an automatic mortar, ball mill,
There is no particular limitation, and examples thereof include those in which an inorganic powder smaller than the resin powder is adsorbed or driven into the resin powder using a jet mill, atomizer, hybridizer or the like. The shape of the powder is amorphous, spherical,
A plate shape, a needle shape, or the like is used and is not particularly limited. These powders may be added alone or in combination of two or more.

As the foaming agent, a chemical foaming agent, a physical foaming agent, a heat-expandable microcapsule, or the like is used. Specific examples of the chemical foaming agent include azo compounds, nitroso compounds, hydrazine derivatives, semicarbazide compounds, azide compounds, organic thermal decomposition type foaming agents such as triazole compounds, organic reaction type foaming agents such as isocyanate compounds, bicarbonates, Inorganic thermal decomposition type foaming agents such as carbonates, sulfites, hydrides,
Inorganic reactive foaming agents such as sodium bicarbonate + acid, hydrogen peroxide + yeast bacteria, zinc powder + acid and the like can be mentioned.
Specific examples of the physical blowing agent include butane, pentane, hexane,
Dichloroethane, dichloromethane, freon, air, carbon dioxide gas, nitrogen gas and the like can be mentioned. Specific examples of the heat-expandable microcapsules include isobutane, pentane, petroleum ether, low boiling point hydrocarbons such as hexane as a core substance, vinylidene chloride, acrylonitrile, acrylic ester,
Examples include microcapsules having a thermoplastic resin made of a copolymer such as methacrylic acid ester as a wall substance,
There is no particular limitation. These foaming agents may be added alone or in combination of two or more.

The conductive fine particles may be any material that is not chemically or electrochemically eluted or altered. Specific examples include carbon black, graphite, oxides such as tin oxide and indium oxide, titanium nitride, chromium nitride,
Nitride such as zirconium nitride and tantalum nitride, carbide such as titanium carbide, zirconium carbide and tantalum carbide,
Examples thereof include borides such as titanium boride, zirconium boride, and tantalum boride, and are not particularly limited. The shape of the conductive fine particles may be amorphous, scaly, spherical, fibrous, or the like. You may add 1 type, or 2 or more types of these electroconductive fine particles.

Reference numeral 10 is a conductive film. The conductive film 10 is formed outside the elastic resin body 8, and specifically,
Any one of electroless plating method, physical vapor deposition method, chemical vapor deposition method or two or more of these methods is used to form a multilayer. The material is aluminum or its alloy,
Copper or its alloy, iron or its alloy, zinc or its alloy, magnesium or its alloy, chromium or its alloy, nickel or its alloy, tin or its alloy, titanium or its alloy, gold or its alloy, silver or its alloy, Palladium or its alloys, platinum or its alloys, rhodium or its alloys, ruthenium or its alloys, etc. are mentioned, and if it is a metal, it will not be specifically limited.

Before the conductive film 10 is formed on the elastic resin body 8, the elastic resin body 8 may be subjected to treatments such as activation, hydrophilization, and addition of a catalyst.

Reference numeral 9 is a metal layer. The method of coating the metal layer is performed by immersing a resin pipe or resin tube on which a conductive film is formed in an aqueous solution containing metal ions for forming the metal layer 9 and immersing the resin pipe or resin on which the conductive film is formed. A method of forming a metal by applying a negative potential to a tube (hereinafter referred to as a forming method 1), or a method of forming a metal by a reduction reaction or a substitution reaction by immersing in a electroless plating solution (hereinafter referred to as a forming method 2) Is mentioned. Specific examples include the shape and length of resin pipes and tubes,
Although various selections can be made depending on the thickness, the forming method 1 includes an electroplating method, an electroforming method, etc., and the forming method 2 includes an electroless plating method, a displacement plating method, etc. to form a metal layer. If possible, it is not particularly limited. The material of the metal layer is aluminum or its alloy, copper or its alloy,
Iron or its alloy, zinc or its alloy, magnesium or its alloy, chromium or its alloy, nickel or its alloy, tin or its alloy, gold or its alloy, silver or its alloy, palladium or its alloy, platinum or its alloy, Examples thereof include rhodium or its alloy, ruthenium or its alloy, and stainless steel, and are not particularly limited. These metal layers 9 may be of one type or of two or more types and may be multi-layered. Further, in the forming method 2, the conductive film 10 may be omitted.

Further, the lead protection member 6 may be plastically deformed at the front end and / or the rear end (FIG. 8). Further, a part of the elastic resin layer may be removed by a laser beam of elastic resin or the like (FIG. 9).

Example 2 An example of the nominal diameter 0.7 will be described in detail. In addition, of space
Except for the cross-sectional area, it is the same as in Example 1. JIS S 6
005, the minimum of the nominal diameter of 0.7
The value is 0.69 mm and the cross-sectional area is 0.374 mm.²so
is there. On the other hand, the maximum diameter is 0.73 mm,
Area is 0.418 mm²Becomes Penetration of 0.69 mm core
2 points on at least a part of the inner surface of the elastic resin
It is necessary to make contact with each other and have a space. Also the sky
Has a gap between the cores of 0.73 mm
Therefore, the cross-sectional area of the space is 0.73.
The difference between the cross-sectional area of the core of mm and the cross-sectional area of the core of 0.69 mm or more
Will be needed. That is, the cross-sectional area of the smallest space is 0.4
18 (mm²) -0.374 (mm²) = 0.044 (m
m²). The minimum for the cross-sectional area of the minimum space
The cross-sectional area ratio of the core is 0.044 (mm²) /0.374
(Mm²) = 0.12. Also mechanical pencil
Has a space for two or more service cores (subsequent cores, broken cores, etc.)
If you do, there will be a problem that the core will not come out even if you knock.
There are cases. Therefore, the cross-sectional area of the largest space is the largest core
Cross-sectional area (0.418 mm²). Ie maximum
The ratio of the minimum core cross-sectional area to the space cross-sectional area of
0.418 (mm ²) /0.374 (mm²) = 1.12
Becomes From the above, the relational expression of Y / X is 0.12.
By setting ≦ Y / X ≦ 1.12, the maximum value of the core diameter
(0.73 mm) has a space even when it penetrates, and the core
The problem that two or more cores do not come out
is there.

Example 3 An example of the nominal diameter 0.9 will be described in detail. In addition, of space
Except for the cross-sectional area, it is the same as in Example 1. JIS S 6
005, the minimum diameter of 0.9 with a nominal diameter
The value is 0.88mm and the cross-sectional area is 0.608mm.²so
is there. On the other hand, the maximum diameter is 0.92 mm,
Area is 0.664 mm²Becomes Penetrates 0.88 mm core
2 points on at least a part of the inner surface of the elastic resin
It is necessary to make contact with each other and have a space. Also the sky
Has a gap of 0.92 mm even when it penetrates
Therefore, the cross-sectional area of the space is 0.92.
The difference between the cross-sectional area of the core of mm and the cross-sectional area of the core of 0.88 mm or more
Will be needed. That is, the cross-sectional area of the smallest space is 0.6
64 (mm²) -0.608 (mm²) = 0.056 (m
m²). The minimum for the cross-sectional area of the minimum space
The cross-sectional area of the core is 0.056 (mm²) /0.608
(Mm²) = 0.09. Also mechanical pencil
Has a space for two or more service cores (subsequent cores, broken cores, etc.)
If you do, there will be a problem that the core will not come out even if you knock.
There are cases. Therefore, the cross-sectional area of the largest space is the largest core
Cross-sectional area (0.664 mm²). Ie maximum
The ratio of the minimum core cross-sectional area to the space cross-sectional area of
0.664 (mm ²) /0.608 (mm²) = 1.12
Becomes From the above, the relational expression of Y / X is 0.09.
By setting ≦ Y / X ≦ 1.12, the maximum value of the core diameter
There is a space even when it penetrates (0.92 mm), and the core
The problem that two or more cores do not come out
is there.

Fourth Embodiment FIGS. 10 and 11 are schematic sectional views of a lead protection member according to a fourth embodiment. In the core protection member 6, an elastic resin pipe (or tube) 15 is inserted in a tubular member 14. A through hole is formed in the elastic resin pipe (or tube) 15, and the core L slides in the through hole. It is also retained in the residual core. The cross-sectional shape and the material of the through hole of the elastic resin pipe (or tube) 15 are the same as those in the first to third embodiments, and the shape has an irregular shape other than the circular shape, and the material is an elastic material. Also,
These elastic resins may contain powders, foaming agents, conductive fine particles, colorants, or the like.

Specific examples of the method for molding the elastic resin pipe (or tube) 15 include compression molding, direct pressure molding, transfer molding, injection molding, extrusion molding, inflation molding, thermoforming such as vacuum molding and pressure molding, and foaming. Molding,
Examples include powder molding, reaction molding (RIM), sinter molding, and casting, but are not particularly limited.

The tubular member 14 is not particularly limited as long as it is a tubular member. As the material, aluminum or its alloy, copper or its alloy, iron or its alloy, zinc or its alloy, magnesium or its alloy, titanium or its alloy, stainless steel or other metal material, ABS, A
S, acrylic resin, polycarbonate, polypropylene, polyethylene, polyester, polystyrene and other thermoplastic resins, alumina, zirconia, ceramic materials such as porcelain, natural materials such as wood, paper, etc., as long as it can form a tubular shape, it is particularly limited Not done. In addition, nickel or chromium, a noble metal, a coating film, a printing pattern, or the like may be previously formed on the outer wall and / or the inner wall of the tubular member by an electroplating method, an electroless plating method, painting, printing, or the like. These tubular members may be a multilayer structure of one kind or two or more kinds.

Examples of the method for fixing the elastic resin pipe (or tube) in the tubular member include, but are not limited to, insertion, press fitting, and adhesion. When the elastic resin pipe (or tube) is fixed by being inserted into the tubular member, the detent presser 16 and the plastically deformable portion may be provided at the front end portion and / or the rear end portion. Further, a metal layer or a resin layer may be formed on the outer surface of the elastic resin pipe (or tube), resin powder or inorganic powder may be attached, or liquid such as water, alcohol or surfactant may be attached. .
When the elastic resin pipe (or tube) is fixed in the tubular member by press fitting, the outer diameter of the elastic resin pipe (or tube) needs to be the same as or slightly larger than the inner diameter of the tubular member. In that case, a metal layer or a resin layer may be formed on the outer surface. However, it is necessary to minimize the deformation of the elastic resin pipe (or tube) during press fitting, and the outer diameter may be appropriately set so that the press fitting strength is larger than the core holding force. When the elastic resin pipe (or tube) has a circular cross-sectional shape, the cross-sectional shape can be changed by intentionally deforming it when press-fitting it into the tubular member. When the elastic resin pipe (or tube) is fixed in the tubular member by adhesion, the adhesive to be used may be appropriately selected depending on the material of each, such as rubber adhesive, epoxy adhesive, hot melt adhesive, etc. Adhesives. The method of applying the adhesive may be a roll coater, a spray method, a brush coating, or the like, and is not particularly limited.
Further, a metal layer may be formed on the outer surface of the elastic resin pipe (or tube).

Fifth Embodiment FIGS. 12 and 13 are schematic sectional views of a lead protection member according to a fifth embodiment. The core protection member 6 includes a resin 17 and an elastic resin 18
Are integrally formed. The forming method is not particularly limited as long as it can be integrally formed by two-color molding or insert molding. Further, the resin 17 and the elastic resin 18 are bonded (adhered)
It may or may not have been done. The cross-sectional shape and material of the holes of the elastic resin 18 are the same as in Example 1,
The shape has an irregular shape other than a circular shape, and an elastic material is used as the material. Further, these elastic resins may contain powder, a foaming agent, conductive fine particles, a coloring agent, or the like.

Example 6 In Examples 1 to 5, the through holes of the elastic resin body may be formed by post-processing (secondary processing). Examples of the post-processing method include a laser beam method (post-processing 1), a cutting method (post-processing 2), and a melting method (post-processing 3). Various specific examples can be selected depending on the material and shape of the elastic resin body. In the post-processing 1, a laser medium that can be melted by heat or a laser medium that can be chemically broken (decomposed) by using a laser beam in the through hole in the elastic resin is used. For example, ruby laser, YA
G laser, glass laser, solid-state laser such as calcium tungstate laser, He-Ne laser,
Gas laser such as Ar laser, Kr laser, CO ² laser, liquid laser such as selenium oxychloride laser, killed laser, Ga-As laser, Ga-
Examples thereof include semiconductor lasers such as Sb laser, Cd-S laser, and Zn-S laser, excimer laser, and the like, and the laser medium is not particularly limited. In post processing 2,
The turning method using a boring tool, the drilling using a twist drill or a half-moon tool, the reaming, the grinding with a grindstone, etc. are mentioned, and the cutting method is not particularly limited. In the post-processing 3, for example, a hot iron is pressed to form a through hole, and the melting method is not particularly limited. The cross-sectional shape and the material of the hole of the elastic resin are the same as those of the first embodiment, and the shape has an irregular shape other than the circular shape, and the material is an elastic material. Further, these elastic resins may contain powder, a foaming agent, conductive fine particles, a coloring agent, or the like.

In the above embodiments, the through hole of the elastic resin body has a uniform cross-sectional shape (for example, ribs and slits are formed over the entire length in parallel to the axis). The through-holes do not have to have a uniform cross-sectional shape as long as the effects of the present invention are exhibited. For example, ribs or hemispherical projections shorter than the entire length of the resin elastic body may be provided on the inner wall of the through hole in a grid pattern or in a zigzag pattern.

[0031]

The lead protector for a mechanical pencil according to the present invention is provided with a space between an elastic resin body having a through hole and a mechanical pencil core, which causes a variation in the diameter of the core. It absorbs variations in power.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view of a conventional mechanical pencil.

FIG. 2 is a schematic partial cross-sectional view of a mechanical pencil equipped with a lead protection member according to the present invention.

FIG. 3 is a schematic cross-sectional view of the lead protection member of Example 1.

FIG. 4 is an example of an inner surface shape of a core protection member.

FIG. 5 shows an example of the inner surface shape of the core protection member.

FIG. 6 shows an example of the inner surface shape of the core protection member.

FIG. 7 shows an example of the inner surface shape of the core protection member.

FIG. 8 is a schematic cross-sectional view of a lead protection member of Example 2.

FIG. 9 is a schematic cross-sectional view of a lead protection member of Example 2.

FIG. 10 is a schematic cross-sectional view of a lead protection member of Example 3.

FIG. 11 is a schematic cross-sectional view of the lead protection member of Example 3.

FIG. 12 is a schematic cross-sectional view of a lead protection member of Example 4.

FIG. 13 is a schematic cross-sectional view of a lead protection member of Example 4.

[Explanation of symbols]

L core (remaining core) S detent member 1-axis tube 2 chuck 3 Chucking member 4 core feeding mechanism 5 Tip member 5a step 6-core protection member 7 Repellent material 8 Elastic resin body 9 metal layers 10 Conductive film 11 space 12 Plastic deformation part 13 Partial removal section 14 Cylindrical member 15 Elastic resin pipe (or tube) 16 Detent press 17 Resin 18 Elastic resin

Claims (5)

[Claims] 1. A lead protection member for a mechanical pencil in which an elastic resin body having at least a through hole is formed inside a lead protection member, wherein the through hole formed in the elastic resin body has a different cross-sectional shape. Lead for mechanical pencil (JI
S S 6005), the mechanical pencil lead is in contact with the inner surface of the elastic resin body at at least two points and has a space between the mechanical pencil core and the elastic resin body. Wick protection member. 2. A lead for a mechanical pencil (JIS S 6
2. The lead protection member for a mechanical pencil according to claim 1, wherein the relationship is 0.09 ≦ Y / X ≦ 1.12, where X is the cross-sectional area of the minimum diameter of (005) and Y is the cross-sectional area of the space. 3. The lead protecting member for a mechanical pencil according to claim 1, wherein the elastic resin has a type A durometer hardness of 10 to 90. 4. The lead protection member for a mechanical pencil according to claim 1, wherein the elastic resin is silicone rubber or nitrile rubber. 5. The lead protection member for a mechanical pencil according to claim 1, wherein the elastic resin is a methylfluoroalkyl-based silicone rubber (fluorosilicone) or a fluoro-dimethyl copolymerized silicone rubber.