JPH0811484A - Mechanical pencil - Google Patents

Abstract

PURPOSE:To use a remaining part of a refill in a good manner and prevent the deterioration of a rotation control section with time as much as possible by providing the rotation control section with its diameter a little larger than the outer diameter of a refill at least on the front side of a refill protection tube, forming the rotation control section by an elastic component and disposing a refill holding component for holding the refill at the rear of the rotation control section. CONSTITUTION:A refill thrusting mechanism is provided in a shaft cylinder, and a refill protection tube 5 is arranged at the end of the shaft cylinder. A rotation control section 6 composed of an elastic component (example: natural rubber) having its diameter a little larger than the outer diameter of a refill L is located at least on the front of refill protection tube 5. A refill holding component 7 for holding the refill is provided at the rear of the rotation control section 6. As a result, a remaining part of refill can be used for writing in a good manner, and the deterioration of the rotation control section with time can be prevented as much as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sharp pencil having a lead core feeding mechanism arranged in a barrel and a lead protection tube at the tip of the barrel.

[0002]

2. Description of the Related Art As a general sharp pencil, the one disclosed in Japanese Utility Model Laid-Open No. 60-62986 is known. Also in the one described in this publication, a lead holding member for holding lead cores fed at appropriate intervals in front of the lead lead feeding mechanism, and a tip pipe (lead protection tube) in front of the lead holding member. ) Has been placed.

[0003]

It can be said that a sharp pencil other than these is used, but when the lead becomes short in writing, this lead holds the lead of the lead lead-out mechanism. It is released from a chuck such as a 30% chuck or a ball chuck. Then, the lead released from the chuck remains between the tip of the chuck and the tip of the sharp pencil (lead protection tube). The remaining lead (hereinafter referred to as the remaining lead) is only lightly held by the lead holding member. Therefore, when writing is performed on this residual core portion, the core rotates, and the writing feeling is poor, and in general, the core is extruded and discharged by the subsequent core, or pulled out and discarded.

That is, the lead holding member is for preventing the free lead lead from falling from the tip of the sharp pencil by its own weight when the chuck is opened in the lead lead-out operation. It is sufficient if the core has a holding force such that it does not fall under its own weight. Therefore, as described above, the lead core rotates in the residual core writing, which is very uncomfortable. Here, it is possible to simply increase the holding force of the lead holding member, but if it is simply increased,
The lead core was fed out, and the lead holding member was deteriorated with time.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a shank having a lead core feeding mechanism arranged in the barrel and a lead protection tube arranged at the tip of the barrel. -In the pencil, a rotation restricting portion having a diameter slightly larger than the outer diameter of the lead core is arranged at least in front of the lead protection tube, the rotation restricting portion is formed of an elastic member, and the core is provided behind the rotation restricting portion. The gist is that a core holding member for holding the above is arranged.

[0006]

When the residual lead is written, the lead lead separated from the chuck is prevented from rotating due to the light holding force of the lead holding member and the pressure contact with the rotation regulating portion. Here, the residual core is pressure-bonded to the rotation restricting portion due to a slight inclination of the core itself due to a writing load and due to a slight curvature of the lead core.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 1 is a shaft of a sharp pencil. Inside the shaft cylinder 1, a chuck 3 having a chuck ring 2 fitted on the outer periphery of the front portion is shown (in the figure, a split chuck is shown). However, it may be a chuck generally called a ball chuck). Although the tip member 4 is screwed to the front of the barrel 1, the tip member 4 may be integrated with the barrel 1. Further, the lead protection tube 5 made of metal, synthetic resin or the like is press-fitted into the tip of the tip member 4, but the lead protection tube 5 may be integrated with the tip member 4. Inside the front end of the lead protection tube 5, a rotation restricting portion 6 made of an elastic member that prevents the lead core L from rotating is arranged. Reference numeral 7 is a lead holding member that holds the lead core L lightly so as not to drop due to gravity.

Each embodiment will be described below. A first example will be described with reference to FIGS. 1 to 3. Inside the lead protection tube 5, a lead holding member 7 having a triangular cross section is arranged. One side of the core holding member 7 having a triangular cross section has
A slit 8 is formed so that it can be expanded in the radial direction. The core holding member 7 was produced by rolling a plate-shaped member, but it may be formed by forming a slit in a pipe-like material and compressing it so that its cross section becomes triangular. Further, an engagement step portion 9 is press-fitted at the tip of the lead protection tube 5 and a fixing ring 10 is press-fitted at the rear side thereof to prevent the lead holding member 7 from falling off the lead protection tube 5.

On the inner side surface of the engaging stepped portion 9 formed at the tip of the lead protection tube 5, there is arranged a rotation regulating portion 6 made of an elastic member having a diameter slightly larger than the outer diameter of the lead core L. . In this example, the rotation restricting portion (elastic member) 11 is arranged by applying it to the inner surface of the engaging stepped portion 9, but the rotation restricting portion 6 may be previously formed as a separate member and attached by adhesion or the like. Further, the rotation restricting portion 6 may be insert-molded on the lead protection tube 5. Further, if the core protection tube 5 is molded from resin, the rotation restricting portion 6 may be molded simultaneously with the core protection tube 5 made of different material by a molding method generally called two-color molding. As the material of the elastic member which is the rotation restricting portion 11, natural rubber, acrylonitrile butadiene rubber, butadiene styrene rubber, silicone rubber,
Any appropriate material can be used as long as it is a material having rubber-like elasticity such as synthetic rubber called fluororubber, various thermoplastic elastomers, and soft vinyl chloride. Further, the gap X formed between the outer diameter of the lead core L and the inner diameter of the rotation restricting portion 6 is 0.01 mm to 0.06 in consideration of the breakage of the lead core and the rotation preventing function.
The range of about mm is preferable.

In this example, the core holding member 7 having a triangular cross section was used. However, as shown in FIG. 4, a general core holding member 11 as shown in the prior art is used as the core protection tube 5. It may be press-fitted inside the tip member 4 at the rear of. Various materials such as acrylonitrile butadiene rubber and silicon rubber can be considered as the material of the core holding member 11, but in consideration of the synergistic effect with the rotation preventing function of the rotation restricting portion 6 due to the residual core writing, the holding force of a general core holding member is considered. Those having a slightly higher holding power are preferable.

A second example will be described with reference to FIG. This is an example in which the rotation restricting portion 6 made of an elastic material is molded by injection molding or the like and is fitted to the tip of the core protection tube 5 that is jointly molded in front of the tip member 4. The rotation restricting portion 6 is fitted into the front member 4 by forming concave and convex portions,
You may fix with an adhesive agent. In this example, the rotation regulating unit 6 can be mass-produced by injection molding or the like,
It is also easy to assemble.

In the first and second examples, the rotation restricting portion 6 is formed on the inner surface of the tip of the lead protection tube 5, but it may be formed over the entire inner surface of the lead protection tube 5, or at least the inner surface of the tip. It is sufficient if it is formed in.

Further, the rotation restricting portion 6 and the core holding member 7 of the present invention have an inner surface 3-9 previously devised by the applicant of the present invention on the inner surface thereof.
By forming the inner surface treatment portion as shown in No. 0992, a better sharp pencil can be provided.

[0015]

According to the present invention, there is provided a sharp pencil in which a lead core feeding mechanism is arranged in the barrel and a lead protection pipe is arranged at the tip of the barrel, and the lead core is provided at least in front of the lead protection pipe. Since the rotation restricting portion having a diameter slightly larger than the outer diameter of the core is formed, and the rotation restricting portion is formed of the elastic member, and the core holding member for holding the core is arranged behind the rotation restricting portion, the residual core writing is Not only can it be satisfactorily performed, but deterioration of the rotation restricting portion with time can be prevented as much as possible.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a lead protection tube portion corresponding to FIG.

3 is a cross-sectional view taken along the line AA corresponding to FIG.

FIG. 4 is a longitudinal cross-sectional view of a main part with another internal part omitted showing another embodiment of the lead holding member.

FIG. 5 is a longitudinal sectional view of a main part with an internal part omitted showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Chuck ring 3 Chuck body 4 Tip member 5 Core protection tube 6 Rotation regulation part 7, 11 Core holding member 8 Slit 9 Engagement step 10 Fixing ring X Gap L Lead core

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[Procedure amendment]

[Submission date] June 5, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Mechanical pencil

[Claims]

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 lead core feeding mechanism is arranged in a barrel and a lead protection tube is arranged at the tip of the barrel.

[0002]

2. Description of the Related Art As a general mechanical pencil, the one described in Japanese Utility Model Laid-Open No. 60-62986 is known. Also in the one described in this publication, a lead holding member for holding lead cores fed at appropriate intervals in front of the lead lead feeding mechanism, and a tip pipe (lead protection tube) in front of the lead holding member. ) Has been placed.

[0003]

It can be said that a mechanical pencil other than those described above is used. However, when the lead becomes shorter with writing, this lead holds the lead of the lead lead-out mechanism. It is released from chucks such as split chuck and ball chuck. Then, the lead released from the chuck remains between the chuck tip and the mechanical pencil tip (lead protection tube). The remaining lead (hereinafter referred to as the remaining lead) is only lightly held by the lead holding member. Therefore, when writing is performed on this residual core portion, the core rotates, and the writing feeling is poor, and in general, the core is extruded and discharged by the subsequent core, or pulled out and discarded.

That is, the lead holding member is for preventing the free lead core from dropping from the tip of the mechanical pencil due to its own weight when the chuck is expanded in the lead lead feeding operation. It is sufficient if the holding force is such that it does not fall under its own weight. Therefore, as described above, the lead core rotates in the residual core writing, which is very uncomfortable. Here, it is possible to simply increase the holding force of the lead holding member, but if it is simply increased,
The lead core was fed out, and the lead holding member was deteriorated with time.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is a sharpening device in which a lead core feeding mechanism is arranged in the barrel and a lead protection tube is arranged at the tip of the barrel. In the pencil, a rotation restricting portion having a diameter slightly larger than the outer diameter of the lead core is arranged at least in front of the lead protection tube, and the rotation restricting portion is formed of an elastic member. The gist is that a core holding member for holding is arranged.

[0006]

When the residual lead is written, the lead lead separated from the chuck is prevented from rotating due to the light holding force of the lead holding member and the pressure contact with the rotation regulating portion. Here, the residual core is pressure-bonded to the rotation restricting portion due to a slight inclination of the core itself due to a writing load and due to a slight curvature of the lead core.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 1 is a mechanical pencil barrel, and a chuck 3 having a chuck ring 2 fitted on the outer periphery of a front portion thereof is provided in the barrel 1 (in the figure, a split chuck is shown). , Which may be a chuck generally referred to as a ball chuck). Although the tip member 4 is screwed to the front of the barrel 1, the tip member 4 may be integrated with the barrel 1. Further, the lead protection tube 5 made of metal, synthetic resin or the like is press-fitted into the tip of the tip member 4, but the lead protection tube 5 may be integrated with the tip member 4. Inside the front end of the lead protection tube 5, a rotation restricting portion 6 made of an elastic member that prevents the lead core L from rotating is arranged. Reference numeral 7 is a lead holding member that holds the lead core L lightly so as not to drop due to gravity.

Each embodiment will be described below. A first example will be described with reference to FIGS. 1 to 3. Inside the lead protection tube 5, a lead holding member 7 having a substantially triangular cross section is arranged. A slit 8 is formed on one side of the core holding member 7 having a substantially triangular cross section so that it can be expanded in the radial direction. The core holding member 7 was produced by rolling a plate-shaped member, but it may be formed by forming a slit in a pipe-shaped material and compressing it so that its cross section becomes substantially triangular . In addition, an engagement step 9 is formed at the tip of the lead protection tube 5.
However, the fixing ring 10 is press-fitted in the rear,
The core holding member 7 is prevented from falling off the core protection tube 5.

On the inner side surface of the engaging stepped portion 9 formed at the tip of the lead protection tube 5, there is arranged a rotation regulating portion 6 made of an elastic member having a diameter slightly larger than the outer diameter of the lead core L. . In this example, the rotation restricting portion (elastic member) 11 is arranged by applying it to the inner surface of the engaging stepped portion 9, but the rotation restricting portion 6 may be previously formed as a separate member and attached by adhesion or the like. Further, the rotation restricting portion 6 may be insert-molded on the lead protection tube 5. Further, if the core protection tube 5 is molded from resin, the rotation restricting portion 6 may be molded simultaneously with the core protection tube 5 made of different material by a molding method generally called two-color molding. Examples of the material of the elastic member that is the rotation restricting portion 6 include natural rubber, synthetic rubber such as acrylonitrile butadiene rubber, butadiene styrene rubber, silicone rubber, and fluororubber, various thermoplastic elastomers, and rubber such as soft vinyl chloride. Any appropriate material can be used as long as it has a material elasticity. Further, the gap X formed between the outer diameter of the lead core L and the inner diameter of the rotation restricting portion 6 is 0.01 mm to 0.06 m in consideration of the breakage of the lead core and the rotation preventing function.
A range of about m is preferable.

In this example, the core holding member 7 having a substantially triangular cross section is used. However, as shown in FIG. 4, a general core holding member 11 as shown in the prior art is used as the core protection tube. 5
It may be press-fitted inside the tip member 4 at the rear of. Although various materials such as acrylonitrile butadiene rubber and silicone rubber can be considered as the material of the core holding member 11, in consideration of the synergistic effect with the rotation preventing function of the rotation restricting portion 6 due to the residual core writing, a general holding force of the core holding member Those having a slightly higher holding power are preferable.

A second example will be described with reference to FIG. This is an example in which the rotation restricting portion 6 made of an elastic material is molded by injection molding or the like and is fitted to the tip of the core protection tube 5 that is jointly molded in front of the tip member 4. The rotation restricting portion 6 is fitted into the front member 4 by forming concave and convex portions,
You may fix with an adhesive agent. In this example, the rotation regulating unit 6 can be mass-produced by injection molding or the like,
It is also easy to assemble.

In the first and second examples, the rotation restricting portion 6 is formed on the inner surface of the tip of the lead protection tube 5, but it may be formed over the entire inner surface of the lead protection tube 5, or at least the inner surface of the tip. It is sufficient if it is formed in.

Further, the rotation restricting portion 6 and the core holding member 7 of the present invention have an inner surface 3-9 previously devised by the applicant of the present invention on the inner surface thereof.
A better mechanical pencil can be provided by forming the inner surface treated portion as shown in No. 0992.

[0014]

According to the present invention, there is provided a mechanical pencil in which a lead core feeding mechanism is arranged in a barrel and a lead protection tube is provided at the tip of the barrel, and a lead core is provided at least in front of the lead protection tube. Since the rotation restricting part having a diameter slightly larger than the outer diameter is arranged and the rotation restricting part is formed by the elastic member, and the core holding member for holding the core is arranged behind the rotation restricting part, the residual core writing is good. Of course, it is possible to prevent deterioration of the rotation restricting portion with time as much as possible.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a lead protection tube portion corresponding to FIG.

3 is a cross-sectional view taken along the line AA corresponding to FIG.

FIG. 4 is a longitudinal cross-sectional view of a main part with another internal part omitted showing another embodiment of the lead holding member.

FIG. 5 is a longitudinal sectional view of a main part with an internal part omitted showing another embodiment of the present invention.

[Explanation of reference numerals] 1 shaft cylinder 2 chuck ring 3 chuck body 4 tip member 5 core protection tube 6 rotation restriction unit 7, 11 core holding member 8 slit 9 engaging step 10 fixing ring X gap L lead core

Claims (1)

[Claims] 1. A sharp pencil in which a lead core feeding mechanism is arranged in a shaft cylinder and a core protection tube is arranged at a tip of the shaft cylinder, wherein a lead core is arranged at least in front of the outer diameter of the lead core. A sharp pencil characterized in that a rotation restricting portion having a slightly larger diameter is arranged, the rotation restricting portion is formed of an elastic member, and a lead holding member for holding a lead is arranged behind the rotation restricting portion.