JP2002316497A - Mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical pencil which facilitates prevention of breakage of a colored lead, an identification of the lead color and erasing of a character at the time of supplementing the leads. SOLUTION: A retractable mechanical pencil comprises a lead case, the forward part of which is detachably connected to a coupling provided at the rear end of a chuck. In this pencil, a chuck-like closing part is provided at the front part of a case body, and a cylindrical clamping member is provided on the outer periphery of the closing part so as to be locked to a longitudinal retracting position. When the case is mounted at the shaft rear of the coupling, the clamping member is locked to the coupling so that the case is fixed, and the colored lead in which a written line can be easily erased by an eraser which is obtained by impregnating a porous baked core with a dye or a pigment ink, is contained in the case. The case is provided with the same color or the same coloring transparency as a color tone written by the colored lead and provided so that the entirety or the part of the case can be visually recognized from the exterior of a barrel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a knock mechanical pencil mainly using a colored sharp core.

[0002]

2. Description of the Related Art A shaft joint is provided at the rear end of a chuck.
A so-called lead cartridge type mechanical pencil in which a lead case is detachably fastened to the rear end of the shaft coupling is known. Conventional pencil leads can be roughly classified into the following four types of manufacturing methods, but when used as a colored sharp lead, all have drawbacks. That is,

[0003] (1) A fired pencil lead obtained by kneading, molding, and then firing the mixture, which comprises graphite as a coloring agent, an organic substance, clay or the like as a binder. The pencil lead obtained by this method has recently reached a sufficient practical strength even for a pencil lead, and is known as a pencil lead that can be erased with an eraser. However, there is a drawback that a pencil lead other than black cannot be manufactured due to the colors of graphite and calcined carbon material used.

(2) A non-fired pencil lead obtained by kneading and molding a wax, a binder, a filler, a pigment, and the like. According to this production method, various kinds of organic pigments can be used, light resistance and weather resistance are good, and a color pencil lead having a vivid hue can be obtained. However, this colored pencil core is not fired and relies mainly on bonding with an organic binder. Therefore, when it is used as a mechanical pencil lead, sufficient strength cannot be obtained, and since it contains waxes, it cannot be erased with an eraser. There are drawbacks that can not be done.

(3) Water- and oil-repellent substances, binders, body materials,
A non-fired pencil lead obtained by kneading and molding a pigment or the like, and further impregnating the open pores formed around the water / oil repellent substance with oils and fats.
According to this production method, when a liquid oil or the like at room temperature is selected as the oils and fats to be impregnated, it is possible to produce a colored pencil lead that can be easily erased with an eraser to the same extent as in (1) above. However, in the case of using a color pencil lead of a vivid hue using an organic pigment, a binder that can be used is limited to an organic polymer substance or the like due to the heat resistance of the pigment, and thus a fine lead such as for a mechanical pencil is used. In this case, there is a disadvantage that sufficient strength cannot be obtained.

(4) A pencil lead obtained by impregnating a light-colored or white fired porous pencil lead obtained by kneading, molding and firing boron nitride, clay, an organic substance and the like with a dye ink.
The line drawn by the pencil lead obtained by this method can be erased with an eraser. However, since clay is used as the binder, the strength is not sufficient as compared with the core of the above (1).

[0007] As an improvement of (4), by kneading, extruding and baking in a non-oxidizing atmosphere a compounded composition containing at least a body material and an organic excipient, the organic excipient is carbonized. Forming a first fired core using the obtained carbide as a binder, and heating the first fired core in an oxidizing atmosphere to form a second fired core made of at least a constitutional material by oxidizing and removing the binder of the carbide; A third fired core body in which pores of the second fired core body are impregnated with a perhydropolysilazane-containing liquid and heat-treated in an inert atmosphere such as a nitrogen atmosphere or an ammonia gas atmosphere to produce silicon nitride. And a high-strength fired sharp core obtained by coloring the third fired core with a coloring agent having excellent light resistance and weather resistance is obtained. In the obtained third fired core, silicon nitride as a binder is finely and uniformly dispersed in the core, and is generated. Further, since the body material is highly oriented, a small amount of silicon nitride is generated. It is easy to develop the strength of the core, and the collapse of the core during writing is uniform.

[0008] However, although the colored sharp core has reached a practical level, the strength of the core and the erasability with an eraser are not sufficient as compared with the black sharp core. Also, there is a problem of how easy to classify as a mechanical pencil, such as the difference between the color tone of the core itself and the written color tone and the differentiation of similar colors.

[0009]

SUMMARY OF THE INVENTION The present invention avoids the problem of accidentally pulling out the refill wick case downward on the chuck side to scatter the built-in wick, preventing breakage when refilling the colored sharp wick. It is possible to provide a mechanical pencil which is easy to identify a core color and has excellent display properties.

[0010]

The present invention has the following arrangement to achieve the above object. In the mechanical pencil according to the first aspect of the present invention, a chuck provided to be pulled rearward by a spring at the tip of a shaft cylinder, and a front part of a refill case can be attached to and detached from a shaft joint provided at a rear end of the chuck. In the knock-type mechanical pencil connected to the above, a chuck-shaped closing portion is provided at a front portion of the case body, and a cylindrical fastening member is locked at an outer periphery of the closed portion at a forward and backward retreat position. When the refill case is mounted on the shaft behind the joint, the fastening member and the joint are locked, and the locking is performed. A force for releasing the locking between the closing portion and the tightening member is provided strongly against the releasing force.

A mechanical pencil according to a second aspect of the present invention is the mechanical pencil according to the first aspect,
In the extra lead case, a colored burned core is impregnated with a dyed or pigment ink into the porous fired core, and the eraser erases the writing line. It is provided so as to be colored or colored and transparent similar to the above-mentioned color tone, so that the whole or a part of the refill case can be visually recognized from the outside of the barrel.

[0012]

Embodiments will be described with reference to the drawings.
FIGS. 1 to 5 show a knocking mechanical pencil according to a first embodiment of the present invention. A chuck 5 has a fastener 7 loosely fitted to the outer peripheral portion of the distal end thereof and then the chuck of the barrel 1 from the rear end side. The locking portion 6 at the outer periphery of the chuck rear end portion is inserted into the insertion hole, and is locked in a connection hole provided in the shaft portion 8c in front of the shaft coupling 8.

A spring 1 is provided between the shaft coupling 8 and the shaft cylinder 1.
3, the fastener 7 is in contact with the tip of the barrel 1, and the chuck 5 is closed to hold the core 14 which is a colored sharp core. The barrel 1 is a transparent resin molded product, and a base 2 to which a tip pipe 3 is fixed is screwed to a tip of the barrel. Further, if a window is formed in the side surface of the barrel 1, the inside of the barrel can be seen even if the barrel 1 is opaque.

The shaft coupling 8 has a stepped portion 8d at the rear end of the shaft portion 8c, and is further provided with a slightly large-diameter cylindrical portion at the rear thereof. An engaging portion 8a is formed.

On the other hand, as shown in FIG.
Is a chuck-like closing portion 12
Is provided, and a core guide portion 10a is provided in a front portion of an inner hole of the case main body 10 serving as a housing portion of the built-in core 15,
The core guide portion 10a and the front end of the closing portion 12 communicate with each other through a small hole that allows only one core to pass through. A cylindrical fastening member 11 is fitted around the outer periphery of the closing portion 12, and the closing member 11 is moved back and forth with respect to the closing portion 12, thereby forming a groove-shaped locking portion provided on the inner surface of the fastening member 11. 11
b and a protrusion or ridge engaging portion 12a provided on the outer periphery of the closing portion 12 is elastically engaged and disengaged so that the tightening member 11 is locked to the closing portion 12 at the forward and backward retreat position. Have been. Further, as shown in the drawing, in a state where the refill lead case 9 is stored, the fastening member 11 is locked at the forward position, the closing portion 12 is closed, and the leakage of the built-in lead is prevented.
Note that the core can be freely inserted into the closing portion 12 when it is opened, and the hole portion is reduced in diameter so as not to be inserted by its own weight when it is closed.

In the refill lead case 9, a built-in lead 15 such as a colored sharp lead is accommodated in a lead receiving portion at the rear of the case main body 10, and an eraser 16 is mounted in a state where the rear end opening is closed. A flange 10c is provided at a rear portion of the shaft 10 and a shaft portion 10d is further provided at a rear portion thereof. A locking portion 10e including an uneven portion is formed on an outer periphery of the shaft portion 10d,
A cap 17 is provided on the outer peripheral portion of the shaft portion 10d so as to be provided with an uneven portion which also engages with the locking portion 10e, and is detachably fixed.

In order to improve the display performance, the cap 17 must be transparent or similar to the colored sharp core so that the eraser 16 can be seen through, and the eraser 16 must be colored similar to the colored sharp core. Can also. Further, the case body 10 is provided as a colored or colored transparent similar to the color tone written with a colored sharp core.

Further, when the refill lead case 9 is mounted on the tubular portion behind the shaft coupling 8 with the tightening member 11 retracted and the closing portion 12 opened, a projecting portion provided on the outer peripheral portion of the tightening member 11 is formed. The locking portion 11a of the ridge and the locking portion 8a provided on the shaft joint 8 are locked to fix the replacement lead case 9. In a normal setting, the fastening members 11a and 11b provided on the outer peripheral portion of the fastening member 11 and the engaging portion 8a provided on the shaft joint 8 release the engagement between the fastening member 11a and the fastening member. A groove-shaped locking portion 11b provided on the inner surface of the projection 11 and a protruding or protruding locking portion 12a provided on the outer periphery of the closing portion 12
The force for releasing the locking of the lock is provided strongly.

[0019]

According to the mechanical pencil of the present invention, when the closing member 11 is locked at the retracted position with respect to the closing portion 12, the refill lead case 9 is placed with the closing portion 12 facing upward as shown in FIG. Perform attachment / detachment. In a state where the core is not gripped by the chuck 5 or a state where the rear end of the core 14 is immersed in the rear end of the chuck 5 as shown in FIG. 4, the replacement core case 9 shown in FIG. It can be mounted with the closing part 12 side facing downward and upward.

If the barrel 1 is transparent and the case body is colored the same as the written color of the core, the difference between the color of the core itself and the written color and the differentiation of the approximate color can be easily identified. Also, it has excellent display properties. If the case body is transparent or colored and transparent, the presence of the core can be confirmed.

[0021] Further, by providing a detachable lead case detachably on the shaft coupling, a combination of a colored sharp lead and an eraser with good erasability for the lead can be specified.
Further, it is possible to specify a combination of chuck mechanisms suitable for the properties of the core. In addition, since the replenishment of the core alone is not performed as a specific unit, it is not necessary to pick a fragile core with a finger and insert the core into the core case at the time of replenishing the core, thereby eliminating the problem of breakage of the core. Therefore, it is possible to solve the problem that the strength of the lead and the erasability of the eraser are not sufficient when a colored sharp lead is mounted on an arbitrary mechanical pencil.

[0022]

The construction and operation of the mechanical pencil of the present invention are as described above, and it is also possible to prevent breakage at the time of refilling the colored sharp lead and to ensure erasability with the eraser. In addition, various types of cores can be easily replaced in replacement core case units, and the display characteristics are excellent, and it is easy to display the identification of the core type and the core color and the display of the name.

[Brief description of the drawings]

FIG. 1 is a partially non-sectional longitudinal sectional view showing a front half of a mechanical pencil according to an embodiment of the present invention, showing a state in which a refill lead case is mounted.

FIG. 2 is a longitudinal sectional view showing a rear half of the mechanical pencil according to the embodiment.

FIG. 3 is a cross-sectional view showing a state in which a refill lead case is attached and detached.

FIG. 4 is a cross-sectional view showing another state in which the extra lead case is mounted.

FIG. 5 is a cross-sectional view showing the entire refill case.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Cap 3 Tip pipe 4 Holding chuck 5 Chuck 6 Locking part 7 Fastener 8 Shaft joint 8a Locking part 8b Step 8c Shaft 8d Step 9 Replacement lead case 10 Case body 10a Core guide 10b Step 10c Flange 10d Shaft 10e Locking part 11 Tightening member 11a Locking part 11b Locking part 12 Closed part 12a Locking part 13 Spring 14 Core 15 Built-in core 16 Eraser 17 Cap

Claims (2)

[Claims] 1. A chuck provided to be pulled rearward by a spring at a tip of a barrel, and a front portion of a refill case is detachably connected to a shaft joint provided at a rear end of the chuck. In the knock type mechanical pencil, a chuck-shaped closing portion is provided at a front portion of the case main body, and a cylindrical fastening member is provided on an outer periphery of the closing portion so as to be locked at a forward and backward retreat position. When the refill lead case is mounted on the shaft portion behind the shaft joint with the tightening member retracted and the closing portion opened, the tightening member and the shaft joint are locked and the force for releasing the lock is released. A mechanical pencil provided with a strong force for releasing the engagement between the closing portion and the fastening member. 2. A refill lead case, in which a porous burned core body is impregnated with a dye or pigment ink, and a colored sharp lead that makes it easy to erase a writing line with an eraser is incorporated. 2. The refill core case is provided so as to be colored or colored and transparent similar to the color tone written with a colored sharp core so that the whole or a part of the refill core case can be visually recognized from the outside of the barrel. Mechanical pencil.