JP2018001685A - Writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in prior arts in which, a barrel is formed of a metal, when the barrel is gripped at fingertips, a user senses a chilly sense (cold sense), the barrel is formed of a metal, so that, cost becomes higher, and the barrel cannot be formed into a complicated shape, like a shape of a resin molding, and in prior arts in which the barrel is formed of a resin, a front shaft (barrel) is formed of a resin, so that, by injection molding, writing instruments having a complicated shape can be molded in mass production, and cost is reduced, however, the cold sense which can be obtained on the barrel formed of a metal, cannot be obtained.SOLUTION: There is provided a writing instrument which has a grip part formed of a material in which, metal powder is dispersed and blended in at least a high polymer material and a heat conductivity is set to 10-350 (W/(m K)).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a writing instrument having a grip portion formed of a polymer material.

  2. Description of the Related Art Conventionally, it is known that a gripping part of a writing instrument such as a mechanical pencil, a ballpoint pen, or a marking pen is formed of metal or resin.

Japanese Patent No. 37002827 Japanese Patent No. 4042281

In the writing instrument described in Patent Document 1, since the shaft tube is made of metal, a cool and cool feeling (cool feeling) is obtained when gripped with a fingertip. However, metal has a high heat dissipation rate and lacks the durability of a cool and cool feeling. Moreover, since it is formed of metal, the cost is high, and a complicated shape such as a resin molded product cannot be obtained.
In the writing instrument described in Patent Document 2, since the front shaft (shaft cylinder) is formed of resin, a complicated shape can be molded in large quantities by injection molding, and the cost can be reduced. However, a cold feeling like metal cannot be obtained.

  The gist of the present invention is a writing instrument having a grip portion formed of a material in which metal powder is dispersed and blended in at least a polymer material and the thermal conductivity is 10 to 350 [W / (m · K)].

The writing instrument of the present invention can be molded into a complicated shape by injection molding because its gripping part is a molded product made of a polymer material, and even a complicated shape can be mass-produced with a mold, so that the cost is low. It can be produced, and the metal powder is dispersed throughout the gripping part, so that the high thermal conductivity of the metal, which does not appear in the polymer material alone, is added, and the thermal conductivity is 10 to 350 [W / (m · K )], A cool feeling can be obtained when the gripping part is gripped with a hand, and a pleasant tactile sensation can be obtained at the part touched by the hand. Thereby, it is possible to have both the goodness of both the shaft tube having the grip portion made of metal and the shaft tube having the grip portion made of resin. That is, if the value of the thermal conductivity of the member is too small, a feeling of cooling cannot be obtained, and if the value is too large, the gripping part is immediately warmed by the heat of the hand and the feeling of cooling is not sustained. Therefore, by setting the range of the thermal conductivity to 10 to 350 [W / (m · K)], a complex structure can be produced at a low cost, while being a molded product of a polymer material. It is possible to provide a writing instrument that maintains a pleasant cold feeling.
Furthermore, the blending ratio of the metal powder in the material in which the metal powder is dispersed and blended with the polymer material is 50% to 60% by weight, thereby maintaining the above-mentioned comfortable cooling feeling when gripped. It is possible to prevent a decrease in the bonding force between the polymer materials due to an increase in the metal occupancy ratio in the polymer material, so that it has the strength to suppress the occurrence of cracks due to falling. is there.
Furthermore, by providing a plurality of protrusions on the outer appearance of the shaft cylinder, air can flow through a groove formed between the protrusions and the protrusions, and cooling of the outer surface of the shaft cylinder can be promoted. Thereby, the surface temperature of the shaft cylinder that has been raised by being gripped can be lowered.

It is an external view of the whole product of a present Example. It is a longitudinal cross-sectional view of the whole product of FIG. It is a front enlarged view in FIG. FIG. 4 is an enlarged view around a chuck set 14 in FIG. 3. It is an external appearance perspective view of the chuck body 17 of a present Example. It is a longitudinal cross-sectional view of the chuck body 17 of a present Example. It is a longitudinal half sectional view of the chuck stopper 15 of the present embodiment. Cross-sectional view of the contact portion when the tip end portion 17a of the chuck body 17 and the through hole 15a of the chuck stopper 15 are in contact with each other (the dotted line represents the central perpendicular to the axial direction of each elastic piece 17n). Imaginary line).

The present invention is used for writing instruments such as mechanical pencils, ballpoint pens, marking pens, and fountain pens.
As such a writing instrument, the gripping part gripped in use may be a part of the shaft tube or may be configured as a separate member from the shaft tube. The shaft tube is formed of one part, the shaft tube is integrally formed by press-fitting, screwing, bonding, welding, fitting, or the like, and the shaft tube of the present invention around the inner tube. A multi-structured shaft cylinder provided with
Since the gripping part in the writing instrument of the present invention uses a material in which metal powder is dispersed and blended with a polymer material, it can be injection-molded, can be molded into a complicated shape, and can be mass-produced, thus reducing the cost. it can. Furthermore, by including metal powder, it is possible to obtain a high thermal conductivity that is not found in polymer materials, and when the thermal conductivity is 10 to 350 [W / (m · K)], the grip portion is gripped. You can get a cool feeling in your hands. Examples of the metal powder include brass, gold, silver, stainless steel, carbon steel, nickel chrome steel, tungsten, iron, copper, platinum, and the like, and those having a particle size of about several nm to several hundred μm can be used. Examples of the polymer material include synthetic resins such as acrylonitrile butadiene styrene (ABS), polypropylene (PP), polybutylene terephthalate (PBT), polystyrene (PS), and polyacrylonitrile (PA). It is possible to combine and mix one or more of each.
If the thermal conductivity of the gripping part is less than 10 [W / (m · K)], the heat of the hand is not easily transmitted to the gripping part of the shaft tube, and a cool feeling cannot be obtained. On the other hand, if the thermal conductivity is greater than 350 W / (m · K), the thermal conductivity is large and a cooling sensation is obtained, but the gripping part is immediately warmed by the heat of the hand, and the cooling sensation is not sustained.
In addition, the weight ratio of the material constituting the writing instrument can be adjusted according to the type of metal used as the metal powder and the blending ratio, adjusting the weight balance of the writing instrument as a whole (adjusting the position of the center of gravity) and strength Can be adjusted. Therefore, the shaft tube is molded with a material in which a metal and a polymer material are blended, the thermal conductivity is 10 to 350 [W / (m · K)], and the blending ratio of the metal and the polymer material is By setting the weight ratio to 50% or more and 60% or less, there is no risk of applying a load on the shaft tube or cracking due to an impact caused by dropping, so that a feeling of cooling can be obtained while ensuring strength, and the cost is low. Can be suppressed.
If the weight ratio is greater than 60%, the metal occupancy ratio in the polymer material increases and the bonding force between the polymer materials weakens, so that there is a possibility that cracking may occur due to an impact at the time of dropping.
When the weight ratio is less than 50%, the thermal conductivity is low, and a cool feeling cannot be obtained.
Furthermore, by providing a plurality of protrusions on the outer appearance of the shaft cylinder, air can flow through a groove formed between the protrusions and the protrusions, and cooling of the outer surface of the shaft cylinder can be promoted. Thereby, the surface temperature of the shaft cylinder that has been raised by being gripped can be lowered.

An example will be described based on the drawings.
In the following description, the front member 2 side described later is referred to as the front, and the pressing member 30 side is referred to as the rear.

  The shaft cylinder 1 includes a tip member 2 and a shaft tube main body 3 disposed behind the tip member 2, and the shaft tube main body 3 includes a front shaft 4 and a rear shaft 5. A core feeding unit 13 is disposed inside the shaft tube 1. In this embodiment, the front shaft 4 has a grip portion on the outer peripheral surface thereof.

  In this embodiment, a back shaft 5 made of acrylonitrile butadiene styrene (ABS) is molded, and the front shaft 4 formed from a material in which iron powder is dispersed and blended with 6 nylon is insert-molded to form an integral shaft cylinder main body. 3 is formed, but the entire barrel can be configured as a single shaft only of a material in which iron powder is dispersed and blended in 6 nylon. The front shaft 4 and the rear shaft 5 have adhesiveness at the contact portion by a combination of 6 nylon and acrylonitrile butadiene styrene (ABS). Other combinations having adhesiveness include the front shaft and the rear shaft. Both may be acrylonitrile butadiene styrene (ABS), and may be appropriately selected.

The gripping portion on the front shaft 4 of the writing instrument of the present example is formed with a dodecagonal cross-sectional outer diameter shape, a plurality of thick circumferential grooves continuous in the circumferential direction on the outer circumferential surface in the longitudinal direction, and the front The distance between the widths is gradually increased from the rear to the rear, and one or more narrow circumferential grooves are formed in the longitudinal direction between the thick circumferential grooves and the circumferential grooves. Thereby, air can flow between the grooves, the cooling of the outer surface of the shaft tube can be promoted, and the surface temperature of the shaft tube that has risen by being gripped can be lowered. (See Figure 1)
Further, the shape is not limited to this shape, and a groove-like shape having a uniform groove width and a shape in which a groove that is continuous perpendicular to the circumferential direction may be provided. By making the groove width uniform and shaped like a continuous wave, it has the effect of preventing slipping by being caught by the fingerprint of the finger when grasping. In addition, by providing a groove that is continuous with the circumferential direction, it is possible to quickly remove the dust in the case that the dust adheres.

The tip member 2 includes a tip ring 12 that is press-fitted and fixed therein, and a slider 8 that is slidable back and forth is urged forward by a tip spring 11 and accommodated on the front shaft 4 of the shaft body 3. They are connected by screwing. More specifically, the tip spring 11 is stretched between the inner step portion 12 a of the tip ring 12 and the outer step portion 8 b of the slider 8.
A core feeding unit 13 is arranged inside the shaft body 3 so as to be urged forward by a cushion spring 21. When a high writing pressure is applied during use, the cushion spring 21 expands and contracts, and the impact on the writing core L is increased. Has eased. Further, by arranging the lead feeding unit 13 so that the chuck set 14 disposed in front of the lead feeding unit 13 described later is included in the tip member 2, the tip member 2 and the chuck set 14 in the axial direction are arranged. The center line is coaxial, and the writing core L can be guided from the core feeding unit 13 to the tip member 2.
A clip 6 is fitted into a reduced diameter portion 5 a formed on the rear outer peripheral portion of the rear shaft 5.

The slider 8 has a stainless steel pipe 7 in the front and a core holding member 10 in the inside by press-fitting, and an O-ring 9 is mounted in a recess 8a formed in the front outer peripheral portion. In the present embodiment, the core holding member 10 has its entire outer peripheral surface pressed and fixed to the inner diameter portion of the slider 8, and more specifically, the core holding portion 10a for holding the writing core L is provided therein. By pressing the front outer peripheral surface of the core holding member 10, which is a part formed on the slider 8, into the slider 8, the inner diameter of the core holding portion 10 a is reduced. By doing so, the diameter of the core pin for forming the core holding part 10a when molding the core holding member 10 can be made larger than the inner diameter of the core holding part 10a when actually used, and the strength of the core pin And stable production can be performed. This configuration is particularly effective for cores having a nominal diameter of 0.3, 0.2 or less, when the core diameter of the writing core L is thin and it is difficult to form the core holding portion 10a. is there. Further, the rear outer peripheral portion of the core holding member 10 is also press-fitted and fixed to the slider 8 so that the core holding member 10 is not easily detached from the slider 8.
A core holding member holding member 31 is press-fitted and fixed behind the core holding member 10 inside the slider 8. The core holding member holding member 31 has an outer diameter slightly larger than the inner diameter of the slider 8, and the inner diameter has an inner diameter with a dimension that prevents the two core L diameters from being arranged in parallel. A core insertion part 31a formed in a mortar shape is formed at the rear end part, and in the space from the tip of the chuck body 17 to the core holding member 10, the core is smoothly inserted into the core holding member 10, and after insertion, Even when the second core comes behind the core holding member, the two cores do not overlap, and even if the core holding member 10 is about to come off due to aging, it can be used without being lost. There is an effect to maintain.
When writing, even if the pipe 7 touches the paper surface due to the wear of the writing core L, the pipe 7 is pushed against the paper surface by the writing pressure along with the wear of the writing core L due to writing, so the writing is performed backward. When the pipe 7 is separated from the paper surface, the slider 8 advances by the tip spring 11. When used in combination with a chuck body 17 that can grip the writing core so as to allow advancement of the writing core, which will be described later, but prevent retraction, the writing held by the core holding member 10 when the slider 8 advances by the tip spring 11. Since the lead L can always be pulled out to the tip of the pipe 7, the writing lead L can maintain the writing state without changing and knocking the pressing member 30 at the rear end, so that writing can be continuously performed.
Further, when carrying, the slider 8 is fitted into the tip ring 12 by the O-ring 9 and the forward / backward movement of the slider 8 is stopped to prevent the unexpected writing core L from protruding. When using again, the pressing member 30 is pressed, the rear end of the slider 8 is pushed by the lead feeding unit 13, and the engagement between the O-ring 9 and the front-end ring 12 is released. It becomes possible.

As described above, the front end surface of the writing core L is in a state where the front end surface of the writing core L is substantially in the same position as the front end surface of the pipe 7 or the writing core L that originally protrudes from the front end surface of the pipe 7 is worn. Since the pipe 7 is pushed against the surface of the paper by the pressure of the writing as the writing core L is worn by writing, the writing can be continued even when the pipe 7 is substantially in the same position as the front end surface of the pipe 7.
This configuration is particularly effective for a writing core having a nominal diameter of 0.3, 0.2 or less when the writing core has a small core diameter. Writing with the writing core L guided from the pipe 7 without protruding the writing core L is possible, and when the writing pressure changes during writing, the writing core L is caught on the paper surface. In some cases, breakage of the writing core L can be prevented.

The lead feeding unit 13 has a chuck set 14 on the front side. The chuck set 14 is provided with a ring 16 having a taper portion 16a whose diameter increases toward the front. The ring 16 is divided into two elastic pieces 17n having a core gripping portion 17i by a slit 17m. In addition, a chuck body 17 having a tip portion 17a formed so as to project forward in the axial direction straight is provided on the front end surface of the elastic piece 17n, and each elasticity of the taper portion 16a and the chuck body 17 is provided. Balls 18 are inserted between the ball seats 17c formed on the pieces. Since there are two elastic pieces 17n, the two balls 18 are arranged at positions facing each other in the radial direction. Further, the chuck body 17 is urged rearward by a chuck spring 19 disposed between the outer flange portion 17 h formed at the rear end of the chuck body 17 and the inner stage 16 b of the ring 16. A rust effect is generated through the balls 18 between the chuck bodies 17 and the writing core L is allowed to move forward but can be prevented from moving backward. In front of the ring 18, a chuck stopper 15 (stopper member) having a through hole 15a having a circular cross section inside and a convex portion (contact portion) 15f on the rear portion is fixed by caulking. The body 17 and the ball 18 are prevented from falling forward.
Here, the chuck stopper 15 is disposed such that the convex portion (contact portion) 15 f is positioned on the inner diameter portion of the tapered portion 16 a of the ring 16.
In addition, the chuck body 17 and the chuck stopper 15 in this embodiment are made of brass, but are molded by a metal material such as iron, stainless steel, and aluminum alloy, polyacetal resin (POM), and polycarbonate resin (PC). The material to be used is not particularly limited. Moreover, although the ring 16 in a present Example is formed with the brass, you may shape | mold with stainless steel or a polycarbonate resin (PC), and the material to be used is not specifically limited. Furthermore, although the ball 18 in the present embodiment is formed of super steel, it may be formed of white or acetal, and the material used is not particularly limited.

The chuck body 17 will be described in detail (FIGS. 8 and 9).
The chuck body 17 of this embodiment is a split chuck, and is entirely surrounded by the ring 16.
The external shape of the chuck body 17 will be described. A head portion 17b is formed at the front portion, and a front end portion 17a is formed on the front end surface of the head portion 17b so as to protrude forward and straight in the axial direction. The tip portion 17a is formed with a cut portion 17q in which both side surfaces of a substantially semicircular shape are dropped when viewed in a cross section, and the outer shape thereof is smaller than the outer diameter of the head portion 17b. Further, it is formed smaller than the inner diameter of the through hole 15a of the chuck stopper 15, and the tip 17a can move back and forth through the through hole 15a when the chuck body 17 grips the core 17i or opens and closes. It is formed in a size that does not contact. The rear portion of the head portion 17b is formed in a tapered shape (outer tapered portion 17e), and the ball seat 17c whose appearance is a concave curved surface (concave portion) is formed on the head portion 17b in front of the outer tapered portion 17e. Is formed. In the present embodiment, the vertical cross-sectional shape of the ball seat 17c is a combination of two types of curved portions, the front curved portion is referred to as the first curved portion 17o, and the rear curved portion is the second curved portion. This is called a curved portion 17p. In the present embodiment, the radius of curvature of the second curved portion 17p is smaller than the radius of curvature of the first curved portion 17o. A reduced diameter portion 17f is formed on the rear side of the head portion 17b so as to be connected to the outer tapered portion 17e of the head portion 17b. The outer diameter of the reduced diameter portion 17f is larger than that of the reduced diameter portion 17f. A large large diameter portion 17g is formed. The outer flange portion 17h is formed behind the large diameter portion 17g, and the outer flange portion 17h has an outer diameter larger than that of the large diameter portion 17g.
Next, the internal shape of the chuck body 17 will be described. A lead gripping part 17i is formed in the front part of the chuck body 17, a first inner taper part 17j is located behind the lead gripping part 17i, and the lead is located behind the first inner taper part 17j. A core insertion hole 17k having a larger inner diameter than the gripping part 17i is formed. The core gripping part 17i is formed from the front end of the tip part 17a to the middle part of the head part 17b. A front portion of a core guide pipe 24 described later is disposed in the core insertion hole 17k, and a second inner taper portion 17l is formed behind the core insertion hole 17k. Further, in the chuck body 17 of the present embodiment, the core gripping portion 17i formed on the elastic piece 17n is formed to be connected to the inner surface of the tip portion 17a, but the core gripping portion 17i is formed on the inner surface of the tip portion 17a. It is good also as a hole larger than the internal diameter of the core holding part 17i, without forming, for example, you may form in the cylindrical shape larger than the magnitude | size of a core holding part. Further, the front end portion of the chuck body 17 may be only the head portion 17b without forming the tip end portion 17a. When the core gripping portion is formed also on the inner surface of the tip portion as in this embodiment, the area of the core gripping portion can be increased, so that the writing core can be gripped more reliably.
From the front end of the tip end portion 17a of the chuck body 17 to the rear portion of the reduced diameter portion 17f, a slit 17m is formed that equally divides the cross section of the chuck body 17 into two in the axial direction. The portion of the chuck body 17 from the front end portion to the rear end portion of the slit 17m is referred to as an elastic piece 17n. In this embodiment, since the slit 17m is formed at two places, there are two elastic pieces 17n. The rear end of each slit 17m is a fulcrum of each elastic piece 17n, and each elastic piece 17n is formed to expand from the fulcrum to the front, so that the chuck body 17 tries to maintain the expanded state. Have self-opening force. During the feeding operation of the writing core L, each elastic piece 17n opens and closes with the fulcrum as a starting point, whereby the writing core L is gripped and released. The slits 17m that divide the chuck body 17 are continuously formed with a constant width, which makes it easy to process the slits, and further allows the chuck body to be expanded with a constant force without any fluctuations. It is possible to supply a chuck body of the quality.

At the rear of the chuck set 14, there is an engagement piece 23 b having a substantially trapezoidal shape with a flat portion at the apex, and an elastic piece 23 a formed on the rear inner diameter portion, and the rear end can be expanded. Is press-fitted into the ring 16. The locking member 23 includes a relay member 22, and the rear end surface of the large-diameter portion 22 a formed at the front end of the relay member 22 is in contact with the front end surface of the locking member 23. Further, an engagement groove 22b that engages with the engagement protrusion 23b is formed on the rear outer peripheral surface of the relay member 22, and the engagement groove 22b is engaged with the engagement protrusion 23b of the locking tool 23. And the opening part is formed in the substantially triangular shape longer than the length of the flat part formed in the engagement protrusion 23b in the component axial direction. Inside the relay member 22, a core guide pipe 24 having one or more writing cores through which the inner diameter is inserted and less than two is disposed. The core guide pipe 24 is arranged from the rear inside of the relay member 22 to the vicinity of the core gripping portion 17i of the chuck body 17, and the writing core L is guided to be press-fitted into the rear outer diameter portion of the relay member 22, so that the writing core L Thus, the writing core L can be reliably inserted from the core tank 26 storing the core to the core gripping portion 17 i of the chuck body 17 without the writing core L being sandwiched by the slit 17 m of the chuck body 17. Further, the core insertion hole 22c is formed so that only one writing core passes between the core guide pipe 24 and the core tank 26, which is the rear portion of the relay member 22, and is smaller than the inner diameter of the core guide pipe 24. By providing, only one writing lead can be reliably inserted from the lead tank 26 to the lead guide pipe 24. The chuck set 14, the locking member 23, and the relay member 22 are attached rearward by a knock spring 25 disposed between the core tank 26 and the core 20 through a core 20 disposed so as to surround them. It is energized. An eraser receiving member 27 is press-fitted to the rear end of the lead tank 26, and an eraser 29 and a pressing member 30 are detachably attached to the eraser receiving member 27. Although the core removal pin 28 is fixed to the eraser 29 by press fitting, it is not always necessary to provide it.
The pressing member 30 includes a fitting pipe 30a and a pressing cover 30b, and is formed by press-fitting and fixing the pressing cover 30b to the fitting pipe 30a. Here, a rectangular slit portion 30c is provided at the substantially central portion of the side surface of the fitting pipe 30a. When the slit portion 30c is bent inward, the inner diameter is shrunk and fitted to the eraser receiving member 27. So that the pressing member 30 is not easily removed. The press cover 30b press-fitted and fixed to the fitting pipe 30a has an inner diameter slightly smaller than the outer diameter of the fitting pipe 30a, and the rear cover 5 has an inner diameter at the rear end of the rear shaft 5. A slightly smaller outer diameter portion and an outer diameter portion slightly larger than the inner diameter of the rear end portion of the rear shaft 5, and the slightly smaller outer diameter portion has a longer axial distance than the slightly larger outer diameter portion. It has become. Further, a recess having a slight depth exists on the rear end side of the slightly larger outer diameter portion, that is, on the side surface of the rear end portion of the pressing member 30. This recess has an effect of allowing the user to know that the pressing member 30 is present even when the user does not look directly at the pressing member 30 when knocking. An anti-slip effect can also be obtained so as not to slip. Moreover, in this recessed part, the seal | sticker which displays a core diameter may be affixed on this part, and since a finger | toe does not touch the edge of a seal | sticker by the effect of a recessed part when it sticks, it is apply | coated to the seal | sticker There is an effect that the adhesive does not adhere to the finger and further prevents the seal from being peeled off during use.

Next, the core feeding operation by pressing the pressing member 30 provided at the rear end of the mechanical pencil will be described.
When the first writing core L is fed out, the writing core L housed in the core tank 26 is first turned vertically downward so that the writing core L stored in the core tank 26 is the rear end of the core gripping portion 17i of the elastic piece 17n in the chuck body 17. Falls by its own weight. By arranging the core insertion hole 22c formed in the core guide pipe 24 and the relay member 22 described above, one writing core L can be reliably inserted to the rear end of the core gripping portion 17i of the chuck body 17.

  Next, when the pressing member 30 starts to be pressed in the front direction of the shaft cylinder 1, the relay member 22 press-fitted in front of the core tank 26 also moves forward together with the core tank 26. At this time, the engagement groove 22b formed in the relay member 22 and the engagement protrusion 23b formed on the inner surface of the elastic piece portion 23a in the engagement tool 23 are in an engaged state. The chuck set 14 that is press-fitted and fixed to the front end of the tool 23 advances integrally with the relay member 22 until the front end of the chuck set 14 comes into contact with the rear end of the tip ring 12. If the slider 8 is housed at this time, the front end of the chuck set 14 comes into contact with the rear end of the slider 8 and pushes the slider 8 forward, so that the O-ring 9 fitted in the tip ring 12 is engaged. Is disengaged, and the slider 8 is biased forward by the elastic force of the tip spring 11.

  Even if the front end of the chuck set 14 comes into contact with the rear end of the tip ring 12 and the movement of the locking tool 23 and the chuck set 14 stops, the rear end of the locking tool 23 can be expanded. Can be pressed. Then, by continuing to press the pressing member 30, the elastic piece portion 23a in the locking tool 23 bends outward due to a load (hereinafter referred to as a knock load) that presses the pressing member 30 in the forward direction of the shaft tube 1, The engagement with the relay member 22 is released. Then, only the lead tank 26 and the relay member 22 can be advanced, and the locking tool 23 and the chuck set 14 are stopped. Can do.

  By continuing to press the pressing member 30, pressing the rear end of the chuck body 17 with the front end of the relay member 22, and moving the chuck body 17 forward, the tip end portion 17 a formed on the chuck body 17 closes the chuck body 17. In this state, it is inserted into a through hole 15a formed in the chuck stopper 15. When the chuck body 17 further moves forward and the wedge effect between the ball 18 and the ring 16 is released, the chuck body 17 expands. At this time, the writing lead L falls by its own weight to the rear end of the lead holding part 10 a in the lead holding member 10 in the slider 8. The forward movement of the relay member 22 and the lead tank 26 due to the pressing of the pressing member 30 ends when the front end of the lead tank 26 and the rear end of the locking tool 23 come into contact with each other.

  When the pressing to the pressing member 30 is released, the relay member 22 and the core tank 26 are moved backward by the knock spring 25. At this time, since the relay member 22 is clamped by the elastic piece portion 23 a of the locking tool 23, the relay member 22 and the locking tool 23 are in a locked state, and the locking tool 23 is inside the core 20. The relay member 22, the locking member 23, and the chuck set 14 are moved backward together until they contact the step 20 a and stop moving. Until the locking member 23 comes into contact with the inner stage 20 a of the core 20, the chuck body 17 is pressed and expanded by the relay member 22.

  After the locking tool 23 comes into contact with the inner stage 20 a of the core 20, the relay member 22 and the core tank 26 are retracted to release the pressure on the chuck body 17, and the chuck body 17 is closed by the chuck spring 19. Since the wedge effect is generated, the core is gripped, and the chuck body 17 stops forward compared to the state where the writing core L is not gripped. At this time, the tip portion 17a is inserted into the through hole 15a of the chuck stopper 15. Thereafter, the relay member 22 and the core tank 26 are further retracted, and the engagement groove 22b formed in the relay member 22 and the engagement protrusion 23b formed on the inner surface of the elastic piece portion 23a in the locking tool 23 are engaged again. At the same time, the rear end of the large-diameter portion 22a of the relay member 22 comes into contact with the front end of the locking member 23, and all the retreating is completed.

Thereafter, the lead holding operation is again performed by pressing the pressing member 30, and the core holding member 17 is advanced together with the chuck set 14 in a state where the locking member 23 and the relay member 22 are engaged, thereby the core holding member. 10, the writing core L is inserted into the chuck body 17, and the chuck body 17 is further utilized by utilizing the difference in relative movement between the locking tool 23, the relay member 22, and the core tank 26 due to the disengagement of the locking tool 23 and the relay member 22. The chuck body 17 is expanded by moving forward, and then the relay member 22 and the locking tool 23 are retracted while being in the locked state, so that the chuck set 14 is retracted while the expanded state of the chuck body 17 is maintained. After the locking tool 23 comes into contact with the inner stage 20a of the core 20, only the relay member 22 and the core tank 26 are retracted to release the pressure on the chuck body 17, and the chuck body 17 is closed by the chuck spring 19. The core is held again, and the tip of the writing core L stays at the advanced position in the core holding member 10, so that the writing ready state is approached.
Then, when the pressing operation of the pressing member 30 is repeated and the writing core L is advanced to the front end surface of the pipe 7, writing becomes possible. As described above, the writing core L may protrude from the pipe 7.
In this embodiment, a rear end knock structure that presses the rear end of the pressing member 30 is employed. However, it is sufficient that the chuck body can be moved back and forth and opened and closed by pressing from the rear side. The operation can employ a structure such as a side knock, a side slide, or a folded knock, and is not particularly limited.

  The tip 317a of the chuck body 17 and the chuck stopper 15 will be described in detail.

The outer shape of the chuck stopper 15 includes a tapered portion 15c whose diameter increases from the front toward the rear, a small diameter portion 15d formed behind the tapered portion, and an outer flange portion 15e formed behind the small diameter portion 15d. , And a convex portion 15f formed to project rearward from the rear end portion of the outer flange portion 15e. The convex portion 15f is formed in an annular shape.
The internal shape of the chuck stopper 15 includes, from the front, a through hole (first inner diameter portion) 15a having a constant inner diameter and a second inner diameter portion 15b formed behind the through hole 15a. The second inner diameter portion 15b is formed to have an inner diameter larger than that of the through hole 15a, and is formed from the rear portion of the outer flange portion 15e to the rear end portion of the convex portion 15f in the outer shape. Yes. The inner diameter of the second inner diameter portion 15b is set such that the outer peripheral surface of the chuck body 17 does not contact even when the chuck body 17 is expanded.
The radius of curvature of the semi-circular cross section of the tip portion 17a of the chuck 17 is formed in the chuck stopper 15 disposed in front of the chuck body 17 and is axially straight with a circular cross section whose center line is coaxial with the chuck body 17. It is formed larger than the radius of the through-hole 15a. When the chuck body 17 is gripped or opened / closed, the distal end portion 17a can be moved back and forth through the through hole 15a and is not sized to contact, but as will be described below, the chuck body 17 is formed. When the expansion restriction is applied, a force greater than the expansion restriction force is applied, and when the outer peripheral surface of the tip portion 17a contacts the inner surface of the through hole 15a, each elastic piece on which the tip portion 17a is formed. It abuts at two places symmetrical with respect to the central perpendicular to the axial direction at 17n.
On the other hand, the inner diameter of the through hole 15a of the chuck stopper 15 is such that when the chuck body 17 is restricted from being expanded, when the force greater than the expansion restricting force is applied to the chuck body 17, the outer peripheral surface of the tip portion 17a and the through hole. When the inner surface of 15a abuts at two symmetrical positions with respect to the central perpendicular to the axial direction of each elastic piece 17n, the slit width of the chuck body 17 at the time of expansion is set to the usable writing core L. The size is restricted so as to be smaller than the core diameter.
When the chuck body 17 grips the writing core L, the tip end portion 17a is always inserted into the through hole 15a. In this embodiment, when the writing core L is gripped, the tip 17a is always inserted into the through-hole 15a. However, the tip 17a is inserted into the through-hole 15a before the advanced chuck body 17 is expanded. What is necessary is just to form so that. As in this embodiment, when the writing core L is gripped, the tip 17a is always inserted into the through hole 15a, so that the tip 17a can be accurately inserted into the through hole when the chuck body 17 moves forward. 15a can be guided and the writing core L can be fed out stably.

Here, the opening / closing operation of the chuck body 17 in the present embodiment and the slit width in the core gripping portion 17i during expansion will be described in detail.
When the pressing member 30 is pressed in the forward direction of the shaft cylinder 1 and the rear end of the chuck body 17 is pressed at the front end of the relay member 22, the chuck body 17 moves forward, and the wedge effect between the ball 18 and the ring 16 is released. Then, the expansion of the chuck body 17 is started. At this time, the ball 18 comes into contact with the chuck body 17 at the connecting portion (inflection point) 17d between the first curved portion 17o and the second curved portion 17p, which is the deepest portion of the ball seat 17c of the chuck body 17. The slit width in the core gripping portion 17i of the chuck body 17 is smaller than the core diameter of the writing core L that can be used.
When the pressing of the pressing member 30 is continued, the convex portion 15f of the chuck stopper 15 and the ball 18 come into contact with each other, the movement of the ball 18 and the shaft cylinder 1 has already stopped, and the chuck stopper 15 is fixed inside. The movement of the ring 16 in the shaft cylinder 1 stops. Also at this time, the ball 18 is in contact with the chuck body 17 at the connecting portion (inflection point) 17d, which is the deepest portion of the ball seat 17c of the chuck body 17, and in the core gripping portion 17i of the chuck body 17. The slit width is smaller than the core diameter of the writing core L that can be used.
If the pressing member 30 is further pressed in this state, the chuck body 17 moves forward with respect to the ring 16 and the ball 18, and the contact position between the ball 18 and the chuck body 17 moves rearward. That is, the chuck body 17 moves forward while the ball 18 and the ball seat 17c are in contact with each other at the second curved portion 17p. Even when the chuck body 17 is located at the most advanced position, the expansion of the chuck body 17 is restricted while the ball 18 is in contact with the second curved portion 17p of the ball seat 17c of the chuck body 17. . Also at this time, the slit width in the core gripping portion 17i of the chuck body 17 is smaller than the core diameter of the writing core L that can be used. More specifically, the ball 18 is the deepest portion (first curve) of the ball seat 17c. Since the second curvilinear portion 17p is in contact with the chuck body 17 at a position shallower than the connecting portion (inflection point) 17d) of the second curvilinear portion and the second curvilinear portion, the slit width in the core gripping portion 17i is It is smaller than the slit width in the core gripping portion 17i until the convex portion 15f and the ball 18 come into contact with each other.
When the pressing of the pressing member 30 is released, the chuck body 17 is retracted, the convex portion 15f and the ball 18 are separated, and the chuck body 17 is further retracted, so that the chuck body 17 is closed and the core is held. When the chuck body 17 moves backward, the chuck body 17 moves in the reverse direction and the amount of expansion of the chuck body 17 decreases.
In the chuck body in this embodiment, the chuck body 17 has two elastic pieces 17n divided by a slit 17m from the front end portion thereof, and the two elastic pieces 17n have a core gripping portion 17i. The chuck body 17 can be moved back and forth with respect to the shaft cylinder 1 by the pressing operation of the pressing member 30 provided on the chuck member 17, and the slit width in the core gripping portion 17 i when the chuck body 17 is expanded can be used. Since it is smaller than the core diameter of the writing core L, the writing core L can be enclosed by the core gripping portion 17i of the chuck body 17 until the pressing operation of the pressing member 30 is completed, and the first core and the second core. The writing core can be fed out in a state where the shaft cores are aligned, and the writing core can be reliably fed out.

When the chuck body 17 sandwiches the writing core L, that is, when the rust effect is generated through the ball 18 between the ring 16 and the chuck body 17, the ball 18 has the first curved portion 17o. As the chuck body 17 advances, the contact position between the ball 18 and the ball seat 17c moves backward. Then, when the chuck body 17 starts to expand, the ball 18 contacts the chuck body 17 at the deepest portion of the ball seat 17c (the connecting portion (inflection point) 17d between the first curved portion and the second curved portion). The chuck body 17 advances and expands in contact with this state. Thus, in this embodiment, when the chuck body 17 starts to advance, the chuck body 17 and the ball 18 are connected to the deepest portion of the ball seat 17c (the connection portion between the first curved portion and the second curved portion ( (Inflection point) In order to move forward in the ring 16 having the tapered portion 16a whose diameter is increased toward the front while maintaining the contact state at 17d), the chuck body 17 expands as the chuck body 17 advances. The amount of opening also increases. For this reason, if the protrusion 15f and the ball 18 are not in contact with each other during the advancement of the chuck body 17, the amount of expansion of the chuck body 17 is the largest when the chuck body 17 is most advanced. In the embodiment, since the convex portion 15f and the ball 18 come into contact with each other while the chuck body 17 is moving forward, when the convex portion 15f and the ball 18 come into contact with each other, the amount of expansion of the chuck body 17 is maximized. It becomes. At this time, the ball 18 is in contact with the chuck body 17 at the deepest portion of the ball seat 17c (the connecting portion (inflection point) 17d between the first curved portion and the second curved portion).
After the contact between the convex portion 15f and the ball 18, as the chuck body 17 advances, the contact position between the ball 18 and the ball receiving seat 17c is shallower than the rear of the ball receiving seat 17c, that is, the deepest portion. It will change in the direction which becomes, and will be in the state contact | abutted with the 2nd curve part 17p. For this reason, as the chuck body 17 advances, the amount of expansion of the chuck body 17 becomes smaller than the amount of expansion when the convex portion 15 f and the ball 18 come into contact with each other. Even when the chuck body 17 is fully expanded, the slit width in the core gripping portion 17i of the chuck body 17 is smaller than the core diameter of the writing core L that can be used. The slit width in the core gripping portion 17i of the chuck body 17 is smaller. As a result, until the pressing operation of the pressing member 30 is completed, the writing core L can be included in the core gripping portion 17i of the chuck body 17, and writing can be performed with the first core and the second core aligned. The lead L can be fed out, and the writing core L can be reliably fed out.

  In the present embodiment, the ring 16 has a tapered portion 16a whose diameter increases toward the front, and a convex portion (abutment portion) 15f is formed in the front portion of the ring 16 at the rear portion thereof. A chuck stopper (stopper member) 15 is disposed, and a convex portion (contact portion) 15f is disposed on the inner diameter portion of the tapered portion 16a of the ring 16, so that the convex portion (contact portion) 15d and ball 18, when the chuck body 17 advances, the convex portion (contact portion) 15 f of the stopper member 15 contacts the ball 18, and the two balls 18 disposed between the ring 16 and the chuck body 17 are in contact with each other. The position in the axial direction is aligned. In this state, when the chuck body 17 further advances, the two elastic pieces 17n of the chuck body 17 are spread evenly in the radial direction. Therefore, each slit width in the core gripping portion 17i of the chuck body 17 when viewed from the cross-section is uniformly smaller than the core diameter, and writing is more reliably performed by the core gripping portion 17i until the pressing operation is completed. The core L can be included. Therefore, the writing core L can be fed out in a state where the first core and the second core are more aligned, and the writing core L can be fed out more reliably.

  In this embodiment, the chuck body 17 has a ball receiving seat 17c formed of a recess on the outer peripheral surface thereof, and the ball 18 and the ball receiving seat 17c are in contact with each other when the chuck body 17 is most advanced. Since the position is on the rear side of the deepest portion of the ball seat 17c (the connecting portion (inflection point) 17d between the first curved portion and the second curved portion), when the chuck body 17 is expanded, the chuck body 17 The slit width in the core gripping portion 17i is smaller than the core diameter. In particular, when the chuck body 17 is most advanced, the ball 18 is the deepest portion of the ball seat 17c (the connecting portion between the first curved portion and the second curved portion). (Inflection point) By abutting on the rear side of 17d), the slip at the time when the chuck body 17 is most advanced is larger than the slit width at the core gripping portion 17i of the chuck body 17 while the chuck body 17 is moving forward. It becomes width is small. For this reason, the inner diameter of the core gripping portion 17i when the chuck body 17 is most advanced is also reduced, and the writing core L can be fed out more reliably in a state where the first and second cores are more aligned. The writing core L can be reliably fed out.

  Furthermore, in this embodiment, the concave curved surface (concave portion) of the ball seat 17c is made of a curved surface having two kinds of curvature radii, and the curvature radius on the rear side is made smaller than the curvature radius on the front side. Compared with the case where the concave curved surface of the ball seat is formed of a concave curved surface (concave portion) having one kind of curvature radius whose longitudinal sectional shape is the same as the curvature radius on the front side, the convex portion and the ball are in contact with each other. Later, the narrowing of the slit width at the core gripping portion of the chuck body becomes steep. For this reason, the chuck body 17 is surely expanded to release the writing core (second core), but after the writing core L is released, the slit width becomes narrow, that is, the inner diameter of the core gripping portion 17i. Narrowing is done quickly, and it is easy to quickly maintain the axis of the first core and the second core. Thereby, the writing core L can be fed out in a state where the first and second cores are more aligned, and the writing core L can be fed out more reliably.

  In this embodiment, a chuck body 17 having two elastic pieces 17n is used, and one ball 18 is arranged on each elastic piece 17n, and the balls 18 are arranged at positions facing each other in the radial direction. However, for example, a three-part chuck body may be used, and a plurality of balls may be arranged in a radial direction or an axial direction with respect to one elastic piece. In any case, the concave curved surface (concave portion) of the ball seat is formed of a curved surface having two kinds of curvature radii, and the curvature radius on the rear side is made smaller than the curvature radius on the front side. After the contact, the slit width at the core gripping portion of the chuck body is narrowed quickly, and it is easy to keep the first and second cores quickly while reliably releasing the writing core. Yes. As a result, the writing core can be fed out in a state where the shaft cores of the first core and the second core are more aligned, and the writing core can be fed out more reliably.

As described above, the mechanical pencil of the present embodiment is capable of surely feeding out the writing core L. Further, as described below, it is possible to more reliably deliver the writing core L more reliably. It is supposed to be.
More specifically, when the chuck body 17 is expanded, the slit width in the core gripping portion 17i of the chuck body 17 is smaller than the core diameter of the writing core L, so that the writing core L completely enters the slit 17m. However, when a part of the writing core L tries to enter the slit 17m, a force is applied to the chuck body 17 so as to expand, and the convexity There is a possibility that the chuck body 17 may be expanded by applying a force on the chuck body 17 that is greater than the expansion restriction force applied to the chuck body 17 caused by the contact between the portion 15f and the ball 18.
In this embodiment, a part of the writing core L tries to enter the slit 17m, and the chuck body 17 is expanded by applying a force greater than the expansion restriction force to the chuck body 17 to the chuck body 17. However, the front end portion 17a of the chuck body 17 and the through hole 15f of the chuck stopper 15 are arranged such that the outer peripheral surface of the front end portion 17a and the inner surface of the through hole 15a are perpendicular to the central perpendicular to the axial direction of each elastic piece 17n. Abuts at two symmetrical positions. And the slit width in the core holding part 17i at the time of expansion is regulated by the contact so as to be smaller than the core diameter of the writing core L that can be used. For this reason, even if a force greater than the expansion restriction force is applied to the chuck body 17 and the chuck body 17 is expanded, the slit width in the core gripping portion 17i is surely the same as that of the usable writing core L. The writing core L can be fed out in a state where the core diameter is smaller and the shaft cores of the first and second cores are surely aligned, and the writing core L can be reliably fed out.
Note that, even in the case of a mechanical pencil using a chuck body that has a tip portion having a substantially semicircular cross section without a cut portion 17q formed at the tip portion of the chuck body 17, as in the present embodiment, the chuck body. The shaft core of each elastic piece in which the tip end portion is in contact with the outer peripheral surface of the tip portion and the inner surface of the through-hole when the force is applied to the force chuck body that is greater than the spread control force You may comprise so that it may contact | abut at two places left-right symmetrical with respect to the central perpendicular to a direction. By doing so, even if the chuck body is subjected to a force greater than the expansion restriction force and the chuck body is expanded, the slit width in the core gripping portion can be surely used. Thus, the writing core can be fed out in a state where the shaft cores of the first and second cores are surely aligned, and the writing core can be reliably fed out.

In the present embodiment, cut portions 17q having both side surfaces cut are provided, and the semicircular cross section of the tip portion 17a formed in a shape that is substantially semicircular in cross section and protrudes from the tip of the chuck body 17 in the axial direction straight. By forming the radius of curvature on the chuck stopper 15 disposed in front of the chuck body 17 larger than the radius of the through hole 15a formed in a straight axial direction with a center line coaxial with the chuck body 17, When the chuck body 17 is subjected to a force larger than the expansion restriction force, the chuck body 17 is expanded to the right and left with respect to the center perpendicular line in the axial direction of the tip 17a formed in the axial straight and the elastic pieces 17n. Two symmetrical places can be brought into contact with each other by line contact (FIG. 8, contact place T). Since the two contact points are in line contact, the movement of the chuck body 17 to the left and right can be stably controlled, and the writing core L can be stably fed until the pressing operation of the pressing member 30 is completed. It can be carried out.
In the present embodiment, cut portions 17q with both side surfaces cut are provided, and the curvature of the semi-circular section of the tip portion 17a formed in a shape that is substantially semi-circular in cross section and protrudes from the tip of the chuck body 17 in the axial direction straight. The chuck stopper 15 disposed in front of the chuck body 17 has a radius larger than the radius of the through-hole 15a formed in a straight axial direction with a center line coaxial with the chuck body 17 so that the chuck body 17 has a chuck. When the body 17 is subjected to a force larger than the expansion restriction force, when the chuck body 17 is expanded, the outer peripheral surface of the tip 17a is the inner surface of the through hole 15a, and the center in the axial direction of each elastic piece 17n. Although the contact is made by line contact at two symmetrical points with respect to the perpendicular, the core is not limited to the contact method described above, and the force when the chuck body expands due to a force exceeding the expansion restriction force due to the contact. Hold The slit width in the section 17i, it is sufficient regulations to be smaller than the core diameter of the writing lead that may be used, the shape of the tip portion of the chuck body is not particularly limited.

In addition, by providing the cut part 17q which cut both the side surfaces of the front-end | tip part 17a like a present Example, the horizontal width of the front-end | tip part 17a becomes narrow, and it is in the through-hole 15a also in the state which is not holding the writing core L The distal end portion 17a can be guided more reliably. Further, the contact portion T between the outer peripheral surface of the tip end portion 17a and the inner surface of the through hole 15a when the chuck body 17 is expanded can be set to an obtuse angle of 90 ° or more, and it is resistant to deformation and has good temporal stability. Can be provided. Since the contact portion T between the outer peripheral surface of the tip portion 17a and the inner surface of the through hole 15a becomes a line formed by the cut portion 17q, the size management of the contact portion T becomes easy after the chuck body 17 is formed. Stable quality chuck body 17 can be supplied.
Further, the shape of the through hole 15a of the chuck stopper 15 is not limited to a circular cross section, and may be, for example, a rhombus or an ellipse. However, in the fourth embodiment, the through hole 15a has a circular cross section. The positional relationship in the circumferential direction between 17 and the through hole 15a is not limited, and positioning at the time of assembly is not required, and an effect excellent in durability for long-term use can be obtained while maintaining productivity.

  In the present embodiment, the tip end portion 17a is formed to have a diameter smaller than that of the head portion 17b of the chuck body 17, whereby the maximum diameter portion of the chuck body 17 can be made as small as possible. By doing so, the outer diameter of the chuck spring 19 inserted from the front of the chuck body 17 and the stopper member having a through hole can be reduced, and a thin mechanical pencil can be provided. In particular, the outer surface of the place where the chuck body is installed is often the part that the user grips at the time of writing, and by reducing the maximum diameter of the chuck body, the outer diameter of the gripping section can be made smaller and thinner. Product design that suits the user can be made possible.

  In the case of 6 nylon and acrylonitrile butadiene styrene (ABS) with various metal powders dispersed, 6 nylon alone, acrylonitrile butadiene styrene (ABS) alone, copper alone and silver alone as the gripping part Table 1 shows a summary of the results of evaluating the strength of cooling sensation and the sustainability of cooling sensation, and the results of the crushing test based on the difference in weight ratio between the examples and the comparative examples. .

The strength of the cooling sensation is `` ◎ '' when the gripping part of the shaft cylinder of the writing instrument molded with the material of each Example and Comparative Example is gripped, `` ◎ '', what feels the cooling sensation `` “△” indicates that the feeling of cooling is weak, “△” indicates that the feeling of cooling is not felt, and “x” indicates that the feeling of cooling is not felt, and ◎, ○, and Δ are judged to be good feelings of cooling.
The sustainability of the cooling sensation is `` ◎ '' if the feeling of cooling is strong for a long time when the gripping part of the shaft cylinder of the writing instrument molded from the material of each example and comparative example is kept. “○” indicates that it feels for a long time, “△” indicates that it feels weak for a long time, and “×” indicates that it does not feel the cooling sensation for a long time. Judging.
In the tip crushing test, the state of shaft cracking when a load of 20 kgf was applied to the tip of the gripping part of the shaft tube of the writing instrument formed of the material of each example and comparative example was confirmed, and only cracks were generated. Is evaluated as “◯”, weakly broken by “△”, strongly broken by “×”, and only cracked “◯” is judged to have good durability.

Examples 1 to 28 show that when the thermal conductivity is 10 to 350 [W / (m · K)], a good feeling of cooling is felt and the feeling of cooling is sustained. Yes. On the other hand, Comparative Examples 1 to 12 indicate that a cool feeling is not felt when the thermal conductivity is less than 10 [W / (m · K)]. Comparative Examples 12 to 13 indicate that a good cooling sensation is obtained when the thermal conductivity is greater than 350 [W / (m · K)], but the cooling sensation is not sustained.
And Examples 1-3, Examples 8-10, Examples 15-17, and Examples 22-24 have shown that durability is good when the weight ratio is 50%-60%. On the other hand, Examples 4-7, Examples 11-12, Examples 18-21, and Examples 25-28 show that the durability is poor when the weight ratio is greater than 60%. Examples 2 to 6 and Examples 8 to 12 show that when the weight ratio is less than 50%, the durability is obtained, but the thermal conductivity is lowered and the cooling sensation cannot be obtained.

DESCRIPTION OF SYMBOLS 1 shaft cylinder 2 tip member 3 shaft cylinder main body 4 front shaft 5 rear shaft 5a reduced diameter part 6 clip 7 pipe 8 slider 8a recessed part 8b outer step part 9 O-ring 10 core holding member 10a core holding part 11 tip spring 12 tip ring 12a Inner step portion 13 Core feeding unit 14 Chuck set 15 Chuck stopper 15a Through hole 15b Second inner diameter portion 15c Taper portion 15d Small diameter portion 15e Outer flange portion 15f Convex portion 16 Ring 16a Taper portion 16b Inner step 17 Chuck body 17a Tip portion 17b Head Portion 17c ball seat 17d connecting portion 17e outer tapered portion 17f reduced diameter portion 17g large diameter portion 17h outer flange portion 17i core gripping portion 17j first inner taper portion 17k core insertion hole 17l second taper portion 17m slit 17n elastic piece 17o first 1 curve part 17p 2nd curve part 17q 18 Ball 19 Chuck spring 20 Core 20a Inner stage 21 Cushion spring 22 Relay member 22a Large diameter part 22b Engaging groove 22c Core insertion hole 23 Locking tool 23a Elastic piece part 23b Engaging protrusion 24 Core guide pipe 25 Knock Spring 26 Core tank 27 Eraser receiving member 28 Core removal pin 29 Eraser 30 Pressing member 30a Fitting pipe 30b Pressing cover 30c Slit portion 31 Core holding member restraint 31a Core insertion portion

Claims (3)

A writing instrument having a grip portion formed of a material in which metal powder is dispersed and blended in at least a polymer material and the thermal conductivity is 10 to 350 [W / (m · K)]. The writing instrument according to claim 1, wherein a blending ratio of the metal powder in a material obtained by dispersing and blending the metal powder with the polymer material is 50% to 60% by weight. The writing instrument according to claim 1 or 2, wherein a plurality of protrusions are provided on an outer appearance of the shaft cylinder.

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