JP2544453Y2 - mechanical pencil - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mechanical pencil capable of effectively utilizing a lead.

[Conventional technology]

Conventionally, when the lead becomes short, the lead is released from a chuck such as a three-piece chuck or a ball chuck that holds the lead. The lead released from the chuck remains between the tip of the chuck and the tip of the mechanical pencil (lead protection tube). This remaining core (hereinafter referred to as the residual core)
It is only lightly gripped by the center detent member. Therefore, when writing is performed on the remnant core, the core rotates and the writing feeling deteriorates. Generally, the core is extruded and discharged by a subsequent core, or the core is discarded. In addition, when the residual core is removed from the core detent member, the above phenomenon is remarkably observed, and the core may drop.

Therefore, various proposals have been made for a core protection tube in order to eliminate or reduce the residual core as much as possible and utilize the core effectively. A typical example is a non-circular cross-sectional shape obtained by squeezing the tip of a core protection tube with a press or the like.
No. 84.

[Problems to be solved by the invention]

The following two functions are required of the core protection tube in order to effectively use the residual core. The first point is that the core protection tube does not drop when the residual core is in the core protection tube (having a core holding function). The second point is that the core protection tube is such that the core does not rotate when writing with the core (there is a core writing function).

Japanese Utility Model Application Laid-Open No. 56-115284 has a wick writing function. However, there is a problem in that unless the inner diameter at the time of drawing is considerably reduced to narrow the core protection tube, the core will rotate or the inner diameter will vary, and the core will not be clogged due to the variation. That is, there is a problem in accuracy for satisfying the core protection function.

[Means for solving the problem]

The present invention has been made in view of the above prior art, and is a mechanical pencil having a lead protection tube at the tip, in which a coil spring is disposed in the lead protection tube, and a core is placed inside the coil spring. The first gist is to form an inner diameter portion that is in contact with a core slightly smaller than the diameter,
A mechanical pencil having a lead protection tube at its tip, wherein a linear spring curved toward the center of the inner diameter of the lead protection tube is disposed in the lead protection tube, and a bent portion of the linear spring forms a lead in the lead protection tube. A mechanical pencil having an inner diameter portion in contact with a core slightly smaller in diameter than the diameter, and having a second gist that powder is fixed to the surface of the linear spring, and having a core protection tube at a tip thereof. An inner diameter portion in which a linear spring curved toward the center of the inner diameter is disposed in the core protection tube, and a curved portion of the linear spring contacts the core having a slightly smaller diameter than the core in the core protection tube. In a third aspect, the linear spring is a wire-shaped spring formed by twisting a plurality of wires.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

 FIG. 1 shows a first embodiment of the present invention.

At the tip of the barrel 1, a core protection tube 2 made of a metal member is attached. A coil spring 3 having a diameter slightly smaller than the diameter of the core is disposed inside the core protection tube 2. Reference numeral 2a is a stopper for fixing both ends of the coil spring 3 to the core protection tube.

As shown in FIG. 2, the same effect can be obtained by disposing the coil spring 3 even when the tip of the barrel 1 is the core protection tube 2.

Further, as shown in FIG. 3, the shape of the coiled spring 3 is set such that the diameter of the coiled spring 3 is made smaller in the middle portion and becomes larger as it advances in both directions. It may be arranged.

The cross section of the coil spring may be polygonal or a wire coil spring.

 FIG. 4 shows a second embodiment of the present invention.

Inside the core protection tube 2, at least one or more (three in FIGS. 4 and 5) linear springs 5 each having an inwardly curved cross section are attached in the longitudinal direction at appropriate intervals. .

Further, as shown in FIG. 6, various shapes such as a quadrangle or a hexagon can be adopted for the cross-sectional shape of the linear spring 5. By making the cross section a polygon, rotation of the core can be prevented as much as possible. On the surface of the linear spring 5, a powder described later is fixed.

Further, as shown in FIG. 7, a plurality of twisted linear springs, so-called wires, are used as springs,
When this is mounted inside the core protection tube 2, the effect is enhanced by preventing the remnant core from retreating and rotating.

In the first and second embodiments described above, the effect is further enhanced by applying the following powder fixing to the coil spring or the linear spring.

Hereinafter, an example for forming the fine protrusions 6 by powder fixing will be described in detail.

The first example is an example shown in FIGS. 8, 9 and 10, in which powder is dispersed on the surface of the linear spring 5. FIG.

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, and acrylic, urethane, and the like. Powders (composites) coated with powder coatings such as epoxy-based and epoxy-based powders, and resin powders with smaller inorganic powders in automatic mortars, ball mills, jet mills, atomizers, and hybridizers (Nara Machinery Co., Ltd.) The resin powder is obtained by adsorbing or driving the inorganic powder into the resin powder. In addition, the above-mentioned powder may be of any suitable shape, such as a sphere, a plate, or a bowl, regardless of the shape. FIG. 8 shows an example in which powder is directly attached to the surface of the linear spring 5. The example of FIG. 9 is an example in which two types of powder (resin powder into which inorganic powder is injected) are used. The example shown in FIG. 10 is an example in which a film 6a is formed by plating after powder is adhered. This plating is wet plating such as electroplating or electroless plating, or dry plating such as vapor deposition, sputtering, or ion plating. The purpose of the plating is to increase the surface hardness. Note that the powder may be provided over the entire circumference of the surface of the linear spring 5, or protrusions may be formed at appropriate intervals.

A first example of a method of attaching powder to the surface of the linear spring 5 will be described.

An example in which a resin powder or a resin powder obtained by adsorbing or driving an inorganic powder into a resin powder will be described. First, these powders are charged (charged when sprayed using a spray or the like). On the other hand, a charge is applied to the surface of the linear spring 5, and after the charged powder is electrically attached to the surface of the linear spring 5, the powder is heated and melted. Alternatively, the surface of the linear spring 5 is heated, and then the powder is sprayed on the surface of the linear spring 5 to be brought into contact therewith and adhered to the surface.

The second example is the example shown in FIGS. 11 and 12, in which powder is adhered to the surface of a linear spring 5 via a base material 7 to form a projection 6 having a surface equal to or harder than the core. Things.

As the powder of this example, the same powder as that of the first example can be used.
It is preferable to use a powder having a needle-like crystal structure which easily gives frictional resistance to the powder. The silicon resin fine powder has the following structural formula of a network structure in which siloxane bonds extend three-dimensionally. In particular, those having an alkyl group at the terminal of the molecular structure.

For example, it is sold under the name of Tospearl 120, Tospearl 130, Tospearl 145, and Tospearl 240 (all of which are manufactured by Toshiba Silicon Corporation) having a methyl group bonded thereto. Depending on the particle size of the silicon resin fine powder, the fine powder may be used as it is.
A resin powder having a large particle diameter, such as silicon, styrene, nylon, polyolefin, epoxy, or polymethyl methacrylate, which is adsorbed or driven into the surface of a resin powder may be used. On the other hand, a material having a large particle diameter may be used by adsorbing or driving it onto a silicon surface having a small particle diameter. The method of the adsorption and the driving is the same as the method of adsorbing and driving the inorganic powder on the resin powder described in the first example.

Examples of the powder having a needle-like crystal structure include silicon nitride, silicon carbide, potassium titanate, and zinc oxide. In particular, a needle-like crystal of zinc oxide having a three-dimensional shape (zinc oxide whisker: Matsushita Electric Industrial Co., Ltd.) is preferable. FIG. 12 shows a projection 6 formed using a powder having a needle-like crystal structure and a substrate 7 interposed therebetween. The example of FIG. 12 is a preferable example because a part of the needle-shaped crystal is added to give a stronger frictional resistance to the core L. The powder having a needle-like crystal structure is preferably used in combination with the other powders described in the first example. The reason is that the powder having a needle-like crystal structure can be appropriately dispersed and protrude to the inner surface.

Base materials include acrylic, urethane and epoxy paints, vinyl acetate, styrene acrylic, vinyl chloride and other thermoplastic resins, acrylic, urethane and epoxy thermosets, silicone Examples thereof include liquid rubber such as rubber, and a plating solution used for electrolytic plating and electroless plating. The substrate has nothing to do with the hardness of the core.

In this example, similarly to FIG. 10 of the first example, the surface of the powder can be plated to improve the fixability and hardness of the powder.

An example of a method for attaching powder to the surface of the linear spring 5 in the second example will be described.

 Various methods can be adopted depending on whether the base material is liquid or solid.

If the base material is liquid, immerse the core protective tube in a mixed dispersion of the base material and powder, and remove unnecessary liquids by air blowing, penetration (penetrating into paper, etc.), and electrostatic removal. Then, a coating layer is formed on the inner surface. Thereafter, the protrusions are solidified by appropriate means such as heating to form projections. If a plating solution is used as the base material, the powder is adhered if a plating process such as electroplating or electroless plating is performed using the plating solution.

When the substrate is solid (powder), the following method can be adopted.

The powder and the substrate are simply mixed and dispersed, or the powder is adsorbed or driven into the substrate, or the powder is adsorbed or driven into the powder, the solvent is added, The processing is performed in the same manner as in the case of. Alternatively, a material obtained by simply mixing and dispersing a powder and a base material, a product obtained by adsorbing or driving a powder into a base material, and a product obtained by adsorbing or driving a base material into a powder are charged (when spraying using a spray or the like). On the other hand, the core protection tube (for metal) is charged,
A charged object is electrically attached to the surface of the linear spring.
Then, it is heated, dissolved and adhered. Alternatively, the core protection tube itself is heated, and then the powder and the base material are sprayed on the surface of the linear spring 5 to be brought into contact therewith to dissolve the base material,
Attach.

If the core protection tube is previously degreased by dissolution, immersion, electrolysis, or the like, the fixability can be improved.

[Action]

When the wick is inserted into or comes into contact with the coil springs 3 and 4 or the linear spring (wire spring) 5 by the knocking operation, the spring is deformed and holds the wick with an appropriate force.

[Effects of the Invention] The present invention is a mechanical pencil having a core protection tube at the tip, in which a coil spring is disposed in the core protection tube, and a diameter of the coil is slightly smaller than the diameter of the core inside the coil spring. A first aspect of the present invention is to provide a mechanical pencil having a core protection tube at its tip, wherein a linear spring curved toward the center of the inner diameter of the core protection tube is disposed in the core protection tube. The curved portion of the linear spring forms an inner diameter portion in contact with the core having a diameter slightly smaller than the diameter of the core in the core protection tube, and the powder is fixed to the surface of the linear spring. The gist of the
A mechanical pencil having a lead protection tube at its tip, wherein a linear spring curved toward the center of the inner diameter of the lead protection tube is disposed in the lead protection tube, and a bent portion of the linear spring forms a lead in the lead protection tube. The third aspect is that an inner diameter portion is formed in contact with the core having a diameter slightly smaller than the diameter, and the linear spring is a wire spring formed by twisting a plurality of wires. The core can be used effectively without waste because it has a holding function and a residual core writing function.

[Brief description of the drawings]

1 is a cross-sectional view of a main part of a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part showing another embodiment, FIG. 3 is a cross-sectional view of a main part showing still another embodiment, FIG. FIG. 5 is a sectional view of a main part of the second embodiment of the present invention, FIG. 5 is a sectional view taken along line AA of FIG.
FIG. 7 is a cross-sectional view showing another embodiment of FIG. 5, and FIGS. 8 to 12 are cross-sectional views of the linear spring in each embodiment in which powder coating is applied to the surface of the linear spring. is there. DESCRIPTION OF SYMBOLS 1 ... Shaft cylinder, 2 ... Core protection tube, 3, 4 ... Coiled spring, 5 ... Linear spring, 6 ... Projection, 7 ... Base material

Claims (3)

(57) [Scope of request for utility model registration] 1. A mechanical pencil having a core protection tube at a tip thereof, wherein a coiled spring is disposed in the core protection tube, and an inner diameter inside the coiled spring contacting a core having a diameter slightly smaller than the diameter of the core. Mechanical pencil formed part. 2. A mechanical pencil having a core protection tube at a tip thereof, wherein a linear spring curved toward a center of an inner diameter of the core protection tube is disposed in the core protection tube, and the core is formed by a curved portion of the linear spring. A mechanical pencil having an inner diameter portion formed in a protective tube and in contact with a core having a diameter slightly smaller than the diameter of the core, and a powder fixed to a surface of the linear spring. 3. A mechanical pencil having a lead protection tube at a tip thereof, wherein a linear spring curved toward a center of an inner diameter of the lead protection tube is disposed in the lead protection tube, and the lead portion is bent by a curved portion of the linear spring. A mechanical pencil having an inner diameter portion in contact with a core having a diameter slightly smaller than the diameter of the core in the protective tube, and wherein the linear spring is a wire-shaped spring formed by twisting a plurality of wires.