JP2003341281A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome the problem such that a following lead Y is retreated while maintaining a state of engagement with a rear inner-surface step part of a lead holding part, that is, such that an operation for paying out the lead cannot be performed due to the formation of a gap between a remaining lead X and the following lead Y, because the following lead Y is engaged with the rear inner-surface step part of the lead holding part, when a lead tank is retreated by an urging force of a coil spring and a chuck body is also retreated, at the release of the operation for paying out the lead. <P>SOLUTION: In a mechanical pencil, the chuck body for holding and releasing the lead and a chuck ring for opening/closing the chuck body are arranged in a barrel tube. The mechanical pencil satisfies the inequality: A+B>C, wherein A represents the longitudinal distance of the contact of the lead holding part of the chuck body with the lead, wherein B represents the distance of the movement of the chuck ring, and wherein C represents the distance of the movement of the chuck body from a state in which the lead is held by the chuck body. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a mechanical pencil in which a chuck body that opens and a chuck ring that opens and closes the chuck body are arranged.

[0002]

2. Description of the Related Art A description will be given with reference to FIG. A tip member 102 is fixed to the tip of the shaft cylinder 101.
A wick protection tube 103 is fixed to the tip of 2. Behind the lead protection tube 103 and inside the tip member 102, a lead holding member 104 holding a lead is press-fitted.
Further, the coil spring 1 is provided inside the barrel 101.
A core tank 106 biased rearward by 05 is disposed so as to be movable back and forth, and a chuck body 107 for gripping and releasing the core is fixed to the front end of the core tank 106. Then, on the front outer periphery of the chuck body 107,
A chuck ring 108 that opens and closes the chuck body 107 is surrounded. By the way, when using, it is common to incline the mechanical pencil (about 60 degrees from the writing surface) for writing. Further, when the lead is consumed due to use, the lead is separated from the chuck body 107 and is held only by the lead holding member 104. Hereinafter, the core separated from the chuck body 107 is referred to as a residual core X, and the core subsequent to the residual core X is referred to as a subsequent core Y.

[0003]

When the lead-out operation of the lead, that is, the lead-out tank 106 is moved forward from the above state, the chuck body 107 holding the succeeding lead Y is chucked by the chuck ring 10.
Advance with 8. As the subsequent core Y advances, the residual core X
Can also be pushed and advanced. Eventually, chuck ring 10
8 contacts the inner surface step of the tip member 102 and its forward movement is blocked, and at this time, the trailing lead Y held by the chuck body 107 is released and is slightly inclined with respect to the axis of the lead tank 106 ( (See FIG. 11). Here, the chuck body 107 is further advanced, but in addition to the trailing lead Y being released from the chuck body 107, the residual lead X is attached to the lead holding member 104.
Since it is held at, its forward movement is blocked. At this time, the succeeding lead Y falls into the large diameter portion 107b located behind the lead gripping portion 107a of the chuck body 107,
Further, it is inclined with respect to the axis of the lead tank 106. That is, the front end portion of the succeeding lead Y is engaged with the rear inner surface step of the lead gripping portion 107a (see FIG. 12).
Here, when the lead-out operation of the lead is canceled, the lead tank 106 is retracted by the biasing force of the coil spring 104, and the chuck body 107 is also retracted. At this time, since the trailing lead Y is engaged with the rear inner surface step portion 107c of the lead gripping portion 107a, the trailing lead Y moves backward while maintaining that state. That is, a gap is formed between the residual core X and the succeeding core Y, and the lead-out operation cannot be performed.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a mechanical pencil in which a chuck body for gripping and releasing a core on a shaft cylinder and a chuck ring for opening and closing the chuck body are arranged. The distance in the longitudinal direction in contact with the core of the core gripping portion is A, and the moving distance of the chuck ring is B.
Further, when the moving distance of the chuck body from the state in which the chuck body grips the core is C, a mechanical pencil satisfying the relation of A + B> C will be summarized.

[0005]

When the residual lead occurs, even if the lead is fed out, the vicinity of the front end of the succeeding lead is located within the range of the lead gripping portion of the chuck body.

[0006]

EXAMPLE One example will be described with reference to FIGS. Inside the front shaft 1, a lead tank 2 for accommodating a plurality of lead is slidably arranged, and a chuck body 3 for holding and releasing the lead is fixed to the front end of the lead tank 2. A chuck ring 4 that opens and closes the chuck body 3 is surrounded by the front portion of the chuck body 3. Reference numeral 5 is an elastic member such as a coil spring that biases the lead tank 2 and the chuck body 3 rearward. Further, reference numeral 6 is a grip member made of a rubber-like elastic body that is detachably attached to the front outer periphery of the front shaft 1, and when the front shaft 1 is knurled on the surface and is gripped by the knurl. You may give a non-slip effect. Further, the front member 7 is detachably attached to the front end of the front shaft 1 by means such as screwing, but it may be integrally formed with the front shaft 1. Inside the tip member 7, a guide member 8 made of a rubber-like elastic body for guiding the core forward is arranged, but it is not always necessary. Further, at the tip of the tip member 7,
Although the lead protection tube 9 made of stainless steel or the like is press-fitted and fixed in order to improve the visibility during writing, it may be integrally formed with the tip member 7. On the other hand, an intermediate stepped portion 7a that restricts the forward movement of the chuck ring 4 is formed in the middle portion of the tip member 7.

A core holding member 10 is arranged inside the core protection tube 9. The core holding member 10 is
Fixing rings 11, 1 press-fitted in the vicinity of both ends of the lead protection tube 9.
Although it is prevented from falling off from the lead protection tube 9 by 2,
The lead holding member 10 has such a length that it can move back and forth in the axial direction of the lead protection tube 9. That is, it can move between the fixed rings 11 and 12. Of course, the inner diameters of the fixing rings 11 and 12 are formed to be larger than the outer diameter of the core, but the fixing ring 12 located in the front is formed to be slightly larger than the outer diameter of the core. The fixing ring 12 prevents the deflection of the core during writing as much as possible. Note that the fixing ring 11 located at the rear part may be omitted, and the guide member 8 may prevent the core holding member 10 from falling off. Further, the outer diameter of the lead holding member 10 is formed to be slightly smaller than the inner diameter of the lead protection tube 9, and the gap 13 is formed by these configurations, but at the stage when the lead is inserted into the lead holding member 10. The lead holding member 10 is expanded by the inserted lead, and the outer surface of the lead holding member 10 contacts the inner surface of the lead protecting tube. By the way, in this embodiment, the outer diameter of the core holding member and the inner diameter of the core protection tube are formed so that the gap 13 is 0.005 mm to 0.05 mm.

The inner surface of the core holding member 10 has 6
Although the individual vertical ribs 14 are formed at equal intervals, they are not limited to this number, and may be formed at, for example, 4 equal intervals or 8 or 10 equal intervals. good. The inscribed circle of these vertical ribs 14 has a diameter slightly smaller than the diameter of the core. That is, the residual core X is lightly held by the vertical ribs 14. More specifically, when a small-diameter core is used, the outer diameter of the core makes line contact with the top of the vertical rib 14, and when a large-diameter core is used, the vertical rib 14 is elastically deformed to make surface contact. To do. When a core having a larger diameter is used, the core holding member 10 itself expands using the gap 13, and the outer surface of the core holding member 10 contacts the inner surface of the core protection tube 9. . In this example, the front end and the rear end of the vertical rib 14 of the core holding member 10 are chamfered (chamfered portions 14a, 14a).
Although b) is applied, the rear end chamfered portion 14a has good insertion of the core, and the front end chamfered portion 14b has good retreat / storability of the core.

Next, a description will be given of the chuck body 3, the chuck ring 4, and the operation movement amount when the lead is fed out. On the front inner surface of the chuck body 3, a lead gripping portion 3a for actually gripping the lead is formed. Let A be the distance in the longitudinal direction (axial direction) of the lead gripping portion 3a. Further, a core insertion hole 3b having a larger diameter than the core gripping portion 3a is formed behind the core gripping portion 3a. Of course, the core insertion hole 3
The inner shape of b is larger than the diameter of the core to be used, but the inner diameter is such that two do not fit. Here, a distance that the chuck ring 4 can move, that is,
The distance until it contacts the inner surface step portion 7a formed on the tip member 7 is B. Further, the maximum operation amount when the lead is paid out, in this example, the inner surface step portion 17 of the rear shaft 17 described later.
The distance until a contacts the rear end portion 1a of the front shaft 1 is C
And And these relations are A + B> C. That is, the distance obtained by adding the moving distance (B) of the chuck ring to the distance (A) of the lead gripping portion is set to be larger than the operation moving amount for feeding the lead. As means for restricting the operation movement amount, a means in which the repellent member is in close contact, a means in which the tip of the chuck body abuts on an inner surface step of the tip member, and a case in which the operation member slips into the rear end of the barrel. There are things.

Hereinafter, the lead protection tube 9 and the lead holding member 10 will be described.
Various materials are listed, but the material is not limited to these, and various selections are possible. Examples of the material of the core protection tube 9 include aluminum or an alloy thereof, copper or an alloy thereof, iron or an alloy thereof, zinc or an alloy thereof, magnesium or an alloy thereof, a metal material such as ABS, AS, acrylic, polycarbonate, polypropylene, polyethylene, Thermoplastic resins such as polyester and polystyrene,
There is no particular limitation as long as it can form a pipe shape, such as a natural material such as a ceramic material such as alumina, zirconia, or clay.

Specific examples of the elastic resin used for the core holding member 10 include epoxy resin, urethane resin, acryl melamine resin, acryl-silicon resin, acryl-
Urethane resin, unsaturated polyester resin, alkyd resin, silicone resin, vinyl chloride, vinyl acetate, chloride-vinyl acetate copolymer, vinyl butyral resin, silicone rubber, urethane rubber, ethylene acrylic rubber, epichlorohydrin rubber, acrylic rubber, ethylene propylene Examples thereof include rubber, chloroprene rubber, natural rubber, isoprene rubber, chlorinated polyethylene, nitrile rubber, styrene elastomer, olefin elastomer, ester elastomer and urethane elastomer. Further, an ultraviolet curable resin can also be used, and specific examples thereof include a monofunctional monomer of an acrylic acid ester or a methacrylic acid ester having a terminal acryloyl group as a functional group, a polyfunctional monomer, or a photopolymerizable prepolymer. As the polymer, polyester acrylate, epoxy acrylate, polyurethane acrylate, polyether acrylate, melamine acrylate, alkyd acrylate are used. The monomer is not used alone, but is used in combination with the photopolymerizable prepolymer, and the photopolymerizable prepolymer is used alone or in combination of two or more. Further, these resins may contain a foaming agent or powder.

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,
Examples include 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. Specific examples of the physical blowing agent include butane, pentane, hexane, dichloroethane, dichloromethane, freon, air, carbon dioxide gas, nitrogen gas and the like. Specific examples of the heat-expandable microcapsules are thermoplastics composed of a low boiling point hydrocarbon such as isobutane, pentane, petroleum ether, and hexane as a core substance, and a copolymer of vinyldene chloride, acrylonitrile, acrylic acid ester, methacrylic acid ester, and the like. Examples include microcapsules having a resin shell.

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. In addition, those powders are coated with a powder coating of acrylic, urethane, epoxy, etc. composite powder, and further, an automatic mortar,
It is also possible to use a ball mill, a jet mill, an atomizer, a hybridizer or the like to adsorb or drive an inorganic powder smaller than the resin powder into the resin powder. The shape of the powder is not particularly limited, and spherical, plate-like, needle-like, etc. can be used. These powders may be added alone or in combination of two or more. Further, by adding powder having a melting point higher than that of the resin,
When a part of the resin is removed by the laser beam, irregularities due to the powder are formed, and variations in core diameter can be more absorbed.

In this embodiment, a rod-shaped body feeding mechanism 15 is detachably attached to the rear portion of the front shaft 1, and an eraser 16 is arranged as a rod-shaped body so that it can be retracted. Briefly, the spiral groove 1 is formed on the inner surface of the rear shaft 17.
8 is formed, and a receiving member 19 for moving the eraser 16 up and down is screwed into the spiral groove 18. A rod-shaped guide member 21 having a slit 20 is interposed between the spiral groove 18 and the receiving member 19, and the rod-shaped guide member 21 is detachably attached to the rear portion of the core tank 2. Has been pressed into. The rod-shaped body guiding member 21
A polygonal portion is formed on the front outer surface of the front shaft and the rear inner surface of the front shaft 1, and they are non-rotatably engaged with each other. That is, by rotating the rear shaft 17 relative to the front shaft 1, the eraser 16 appears and disappears from the rear end of the rear shaft 17. Reference numeral 22 is a clip fixed to the rear shaft 17, but it may be integrally formed with the rear shaft 17.

Next, the operation will be described. Figure 1 (Figure 2)
When the lead is fed out from the state shown in (2), that is, the rear shaft 17 is pressed and the lead tank 2 is moved forward, the chuck body 3 holding the succeeding lead Y moves forward together with the chuck ring 4. As the succeeding lead Y advances, the residual lead X is also pushed and moved forward.
Eventually, the chuck ring 4 comes into contact with the inner step 7a of the tip member 7 and its forward movement is blocked (see FIG. 4).
The trailing core Y gripped by the chuck body 3 is released and is slightly inclined with respect to the axis of the lead tank 2, but the front end of the trailing core Y is located at the inner diameter of the lead insertion hole 3b as shown in the prior art. Since it is not in contact with the inner diameter of the lead gripping portion 3a which is smaller than the inner diameter of the lead insertion hole 3b, the inclination angle of the succeeding lead Y is extremely small (see FIG. 5). Here, the chuck body 3 further advances, but since the trailing lead Y is released from the chuck body 3 and the residual lead X is held by the lead holding member 10,
Its forward movement is blocked. At this time, the tip of the trailing lead Y is located near the rear of the lead gripping portion 3a of the chuck body 3. That is, since the grip portion 3a has a sufficient length, the front end of the trailing lead Y can be located within the range of the grip portion 3a (see FIG. 6). Here, when the lead-out operation of the lead is released, the lead tank 2 is retracted by the urging force of the elastic member 5, the chuck body 3 is also retracted, and the released chuck body 3 contacts the chuck ring 4. At this time, a gap is momentarily formed between the trailing lead Y and the remaining lead X, and the retracting chuck body 3 tries to close, but the trailing lead Y is located near the rear part of the lead gripping portion 3a. Therefore, the inclination angle of the succeeding lead Y gradually decreases in association with the closing operation of the chuck body 3, and eventually the succeeding lead Y falls by its own weight along the surface of the lead gripping portion 3a, and the remaining lead again. Contact with X (see FIG. 7).

A second example will be described with reference to FIG. This is an example in which a guide member 23 having a through hole 23a having a diameter slightly larger than the diameter of the core is inserted and attached inside the core tank 2. Of course, the through hole 23a has a diameter that does not allow two cores.
Since the core insertion hole 3b of the chuck body 3 is extended rearward, the inclination of the succeeding core Y is prevented as much as possible. Therefore, even when the angle formed between the writing surface and the mechanical pencil is reduced when the lead is drawn out, the lead can be drawn out smoothly. In the above example, an example in which the core holding member 10 is arranged in the core protection tube 9 fixed to the tip of the barrel 1 has been described, but this is because the residual core X is used more effectively. It may be applied to a general mechanical pencil as shown in FIG. That is, in the example shown in FIG. 9, since the guide member 8 that holds the lead away from the chuck body is located behind the lead protection tube 9, if the guide member 8 moves away from the guide member 8, the residual core is removed. X is dropped from the lead protection tube 9 by its own weight. However, since the relational expression (A + B> C) of the present invention is satisfied, good lead-out can be secured. Further, although the chuck body 3 in this embodiment is made of a metal material, it may be a resin molded product.
However, it is preferable to use a metal material in order to reduce the retreat amount of the trailing lead and reduce the discomfort during writing. In addition, in the present embodiment, the distance of the lead gripping portion 3a is formed to be long, but the rear portion of the lead gripping portion of the usual chuck body is not extended and formed, but the front portion is extended and formed. As a result, the distance of the lead gripping portion is increased. By minimizing the receding caused by the contact of the subsequent core with the chuck body after the chuck body contacts the chuck ring, the gap generated between the chuck body and the residual core is prevented as much as possible. Further, although a large moving distance of the chuck ring is adopted in the present embodiment, if it is too large, the lead-out amount of the lead also becomes large and an uncomfortable feeling occurs, so that an appropriate setting is necessary.

[0017]

The present invention is a mechanical pencil having a chuck body for gripping and releasing a core on a shaft cylinder, and a chuck ring for opening and closing the chuck body. When the distance in the longitudinal direction in contact with the core is A, the moving distance of the chuck ring is B, and the moving distance of the chuck body from the state where the chuck body holds the core is C, A + B> C Since it is a mechanical pencil that satisfies the relationship, the lead can be reliably extended.

[Brief description of drawings]

FIG. 1 is a vertical half sectional view showing a first example of the present invention.

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

FIG. 3 is an enlarged cross-sectional view of an essential part of FIG.

FIG. 4 is a longitudinal sectional view of a main part for explaining the operation.

FIG. 5 is a longitudinal sectional view of an essential part for explaining the operation.

FIG. 6 is a longitudinal sectional view of an essential part for explaining the operation.

FIG. 7 is a longitudinal sectional view of an essential part for explaining the operation.

FIG. 8 is a vertical cross-sectional view of a main part showing a second example.

FIG. 9 is a vertical cross-sectional view of a main part showing a third example.

FIG. 10 is a longitudinal sectional view of a main part showing a conventional example.

FIG. 11 is a longitudinal sectional view of a main part for explaining a conventional operation.

FIG. 12 is a vertical cross-sectional view of a main part for explaining a conventional operation.

FIG. 13 is a vertical cross-sectional view of a main part for explaining a conventional operation.

[Explanation of symbols]

1 front axis 1a rear end 2-core tank 3 chuck body 3a lead gripping part 3b core insertion hole 4 chuck ring 5 Repulsion member 6 Grip member 7 Tip member 7a Inner surface step 8 Guide member 9 core protection tube 10-core holding member 11 fixing ring 12 fixing ring 13 gap 14 vertical ribs 14a Chamfer 14b Chamfer 15 Rod-shaped body feeding mechanism 16 eraser 17 Rear axle 17a Inner surface step 18 spiral groove 19 Receiving member 20 slits 21 Bar-shaped body guide member 22 clips 23 Guide member X remnant core Y subsequent core

Claims (5)

[Claims] 1. A mechanical pencil in which a chuck body for gripping and releasing a core on a shaft cylinder and a chuck ring for opening and closing the core are arranged, the mechanical pencil being in contact with the core of a core gripping portion of the chuck body. When the distance in the direction is A, the moving distance of the chuck ring is B, and the moving distance of the chuck body from the state where the chuck body holds the core is C, the sharpness satisfying the relation of A + B> C is obtained. Pencil. 2. The mechanical pencil according to claim 1, wherein a lead holding member is arranged near the tip of the barrel. 3. The outer shape of the lead holding member is formed to be slightly smaller than the inner shape of the barrel in which the lead holding member is provided, and in front of the lead holding member, from the barrel of the lead holding member. The mechanical pencil according to claim 1, further comprising an inner surface step portion for preventing the mechanical pencil from falling off. 4. The sharpening member according to claim 2 or 3, wherein the cross-sectional shape of the inner surface of the lead holding member is modified and the lead holding member is arranged so as to be movable back and forth. Pencil. 5. The outer shape of the lead holding member does not contact the inner surface of the barrel when the lead is not inserted, while elastically expands and contacts the inner face of the barrel when the lead is inserted. The mechanical pencil according to any one of claims 2 to 4, characterized in that.