JP2022041062A

JP2022041062A - Chuck for mechanical pencil

Info

Publication number: JP2022041062A
Application number: JP2020146074A
Authority: JP
Inventors: 良昌菅原; Yoshimasa Sugawara
Original assignee: Pilot Corp
Current assignee: Pilot Corp
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2022-03-11

Abstract

To provide a chuck for a mechanical pencil capable of reducing decrease of core holding power even if part of a tip of a core holding part is worn.SOLUTION: A chuck for a mechanical pencil includes a core holding part 11 divided into multiple pieces and a screw part 13 with a recess 15 and a protrusion 14 formed continuously in the core holding part 11. A tip part 16 is formed at the top of the protrusion 14. In a cross section along a longer direction, the protrusion 14 is alternately and continuously formed of a high tip part 16a in which a relative height from a bottom surface of the recess 15 to the tip of the protrusion 16 is high and of a low tip part 16b in which the relative height is low.SELECTED DRAWING: Figure 1

Description

本発明は、芯の保持を確実に行うために芯保持部にネジ部を形成したシャープペンシル用チャックに関するものである。 The present invention relates to a mechanical pencil chuck in which a threaded portion is formed in a core holding portion in order to reliably hold the lead.

従来、チャックの芯保持部内面に凹凸部を形成し、かつ該凹凸部の頂部に鋭角の尖部を形成したシャープペンシル用チャックが知られている。（特許文献１参照） Conventionally, there is known a mechanical pencil chuck in which an uneven portion is formed on the inner surface of a core holding portion of the chuck and an acute-angled tip is formed on the top of the uneven portion. (See Patent Document 1)

しかしながら、上記シャープペンシル用チャックのように芯保持部の頂部に鋭角の尖部を形成した場合、チャックの芯保持部をバネなどの弾性体で強く締め付けなくとも、シャープペンシル用の芯を強く保持することが可能であるが、常に鋭角な尖部で芯を保持しているため、繰り返しの使用により尖部が摩耗することで、芯保持力が弱くなってしまう虞があった。 However, when a sharp point is formed at the top of the lead holding portion like the above-mentioned mechanical pencil chuck, the lead for the mechanical pencil is strongly held without strongly tightening the lead holding portion of the chuck with an elastic body such as a spring. However, since the lead is always held by the sharp tip, there is a risk that the lead holding force will be weakened due to the wear of the tip due to repeated use.

実開昭６２－１１４７８８号公報Jitsukaisho 62-114788 Gazette

本件発明者は、鋭意の検討に基づく様々な試作と評価を繰り返す中で、シャープペンシル用チャックの芯保持部の尖部が摩耗により丸まっても別の尖部により芯を保持することが芯の保持力の低下を防止することに効果的であることを知見した。 The inventor of the present invention has repeatedly made various prototypes and evaluations based on diligent studies, and even if the tip of the lead holding portion of the mechanical pencil chuck is rounded due to wear, the lead is held by another tip. It was found that it is effective in preventing a decrease in holding power.

本発明は、以上の背景をもとになされたものであり、その目的とするところは、芯保持部の尖部の一部が摩耗しても芯保持力の低下を低減することができるシャープペンシル用チャックを提供することである。 The present invention has been made based on the above background, and an object thereof is a mechanical pencil capable of reducing a decrease in the lead holding force even if a part of the tip of the lead holding portion is worn. It is to provide a chuck for a pencil.

本発明は、芯保持部が複数に分割され、楔作用により当該芯保持部で芯を保持するシャープペンシル用チャックであって、前記芯保持部に凹部と凸部が連続的に形成されたネジ部を備え、前記凸部は内方へ向かって突出すると共に当該凸部の先端に尖部が形成され、
長手方向に沿った断面において、前記凸部は、前記凹部の底面から前記尖部の先端までの相対的な高さが高い高尖部と低い低尖部とにより交互に連続して形成されていることを特徴とするシャープペンシル用チャックである。 The present invention is a mechanical pencil chuck in which a core holding portion is divided into a plurality of parts and the core is held by the core holding portion by a wedge action, and a screw having concave portions and convex portions continuously formed in the core holding portion. The convex portion is provided with a portion, and the convex portion protrudes inward and a tip is formed at the tip of the convex portion.
In a cross section along the longitudinal direction, the convex portion is formed alternately and continuously by a high sharp portion having a high relative height from the bottom surface of the concave portion to the tip of the peak and a low sharp portion having a low relative height. It is a chuck for mechanical pencils, which is characterized by being present.

本発明によれば、芯保持部の凸部に高さの異なる高尖部と低尖部とが交互に連続して形成されているため、芯保持部で芯を保持した際に高尖部が摩耗により先端が丸まっても、低尖部に芯が当接するようになることで芯を保持力が低下することを低減することができる。 According to the present invention, since the high-pointed portion and the low-pointed portion having different heights are alternately and continuously formed on the convex portion of the core holding portion, the high-pointed portion is formed when the core is held by the core holding portion. However, even if the tip is rounded due to wear, it is possible to reduce the decrease in the holding force of the core because the core comes into contact with the low tip portion.

また、凹部の底面から高尖部の先端までの高さをＸとし、凹部の底面から低尖部の先端までの高さをＹとしたとき、０．５Ｘ＜Ｙ＜０．９Ｘの関係を満たすよう構成してもよく、この場合、繰り返しの使用により高尖部が摩耗しても芯保持力の低下が大きくなる前に低尖部により芯保持力を維持することができるとともに、高尖部が摩耗しても芯保持力を維持できる間はすぐには低尖部と芯が当接しないため、長期にわたり芯保持力が維持可能となる。 Further, when the height from the bottom surface of the recess to the tip of the high tip is X and the height from the bottom of the recess to the tip of the low tip is Y, the relationship of 0.5X <Y <0.9X is established. It may be configured to satisfy, and in this case, even if the high tip is worn due to repeated use, the core holding force can be maintained by the low tip before the decrease in the core holding force becomes large, and the high tip can be maintained. As long as the core holding force can be maintained even if the portion is worn, the low tip and the core do not immediately come into contact with each other, so that the core holding force can be maintained for a long period of time.

さらに、チャックの長手方向に沿った断面において、高尖部の内角と低尖部の内角とを同一の角度で形成してもよく、この場合、高尖部で芯を保持した状態と低尖部で芯を保持した状態とで芯保持力をの変化が小さいため、使用者が違和感を感じることなく使用を継続できる。尚、本発明における同一の角度とは、ネジ部の加工時のばらつきによる微小の角度変化は同一の角度に含めるものとする。 Further, in the cross section along the longitudinal direction of the chuck, the internal angle of the high-pointed portion and the internal angle of the low-pointed portion may be formed at the same angle. Since the change in the core holding force is small when the core is held by the part, the user can continue to use the core without feeling any discomfort. In addition, the same angle in the present invention means that a minute angle change due to a variation during processing of the threaded portion is included in the same angle.

さらにまた、高尖部及び低尖部の内角をＮとしたとき、３０°＜Ｎ＜７０°を満たすよう構成してもよく、Ｎを３０°より大きく形成することで、尖部で芯を保持した際の芯に与えるダメージを最小限にして芯の折損を防止できるとともに尖部の摩耗を防止し、Ｎを７０°より小さく形成することで、尖部が摩耗しても芯保持力を維持し易くなる。 Furthermore, when the internal angle of the high-pointed portion and the low-pointed portion is N, it may be configured to satisfy 30 ° <N <70 °, and by forming N larger than 30 °, the core is formed at the apex. It is possible to prevent the core from breaking by minimizing the damage to the core when it is held, and to prevent the wear of the tip. By forming N smaller than 70 °, the core holding force is maintained even if the tip is worn. It will be easier to maintain.

また、少なくとも前記芯保持部の表面に無電解メッキ層が形成されていてもよく、この場合、メッキ層により芯保持部の高尖部および低尖部の両尖部の摩耗が抑制されるため、より長期に渡って芯保持力を維持することができることから好適である。
尚、チャックに施す無電解メッキとしては、ニッケル－燐メッキ、又はニッケル－ボロンメッキが好適に使用できる。 Further, at least the electroless plating layer may be formed on the surface of the core holding portion, and in this case, the plating layer suppresses the wear of both the high and low apex portions of the core holding portion. , It is preferable because the core holding force can be maintained for a longer period of time.
As the electroless plating applied to the chuck, nickel-phosphorus plating or nickel-boron plating can be preferably used.

本発明によれば、芯保持部の高尖部が摩耗しても低尖部により芯を保持することで芯保持力の低下を低減することができるシャープペンシル用チャックを提供できた。 According to the present invention, it is possible to provide a mechanical pencil chuck capable of reducing a decrease in the lead holding force by holding the lead by the low tip even if the high tip of the lead holding portion is worn.

本発明のシャープペンシル用チャックを示す縦断面図である。It is a vertical sectional view which shows the chuck for a mechanical pencil of this invention. 図１の要部（ネジ部）を拡大した拡大断面図である。It is an enlarged sectional view which expanded the main part (screw part) of FIG. 図１の実施形態のシャープペン用チャックで芯を保持した状態を説明するための図である。It is a figure for demonstrating the state which held the lead by the mechanical pencil chuck of the embodiment of FIG.

以下、図１及び図２に基づいて本発明における実施例１のシャープペンシル用チャックを説明する。また、図１の左側を前方とし右側を後方とすると共に芯保持部がある軸心側を内方と表現しその反対側を外方と表現する。尚、図１はシャープペンシル用チャック１を示す縦断面図であり、図２は図１の要部（ネジ部）を拡大した拡大断面図である。 Hereinafter, the mechanical pencil chuck of the first embodiment in the present invention will be described with reference to FIGS. 1 and 2. Further, the left side of FIG. 1 is referred to as the front and the right side is referred to as the rear, and the axial center side where the core holding portion is located is expressed as the inner side, and the opposite side is expressed as the outer side. FIG. 1 is a vertical cross-sectional view showing a chuck 1 for a mechanical pencil, and FIG. 2 is an enlarged cross-sectional view of a main part (screw part) of FIG.

図１に示すように、シャープペンシル用チャック１（以降チャック１と表現）は、前部に複数に分割（本実施形態ではすり割り加工により２分割）された芯保持部１１を有している。また、芯保持部１１の内周面にはネジ部１３が形成され、ネジ部１３は、図２に示すように、内方に向かって突出する凸部１４と外方へ向かって凹む凹部１５とが形成してある。そして、凸部１４は、その内方側の頂部に尖部１６が形成されているとともに、凹部１５から尖部１６の先端までの高さが高い高尖部１６ａと、相対的凹部から尖部１６の先端までの高さが低い低尖部１６ｂと、が長手方向に沿って交互に連続して形成されている。 As shown in FIG. 1, the mechanical pencil chuck 1 (hereinafter referred to as chuck 1) has a core holding portion 11 divided into a plurality of parts (in the present embodiment, divided into two by grinding) at the front portion. .. Further, a threaded portion 13 is formed on the inner peripheral surface of the core holding portion 11, and as shown in FIG. 2, the threaded portion 13 has a convex portion 14 protruding inward and a concave portion 15 recessed outward. And are formed. The convex portion 14 has a high apex 16a having a high apex 16 formed at the apex on the inner side thereof and a high height from the concave portion 15 to the tip of the apex 16, and a relative concave portion to the apex. The low pointed portion 16b having a low height to the tip of 16 is formed alternately and continuously along the longitudinal direction.

尚、具体的にはチャック１は黄銅で形成してあり、内外面を含む表面全体に無電解ニッケル－燐メッキを施してある。これにより、芯保持部１１で芯を保持した際の高尖部１６ａ及び低尖部１６ｂの摩耗を抑制できることから、より長期に渡って芯保持力を維持することができる。 Specifically, the chuck 1 is made of brass, and the entire surface including the inner and outer surfaces is electroless nickel-phosphorus plated. As a result, the wear of the high-pointed portion 16a and the low-pointed portion 16b when the core is held by the core holding portion 11 can be suppressed, so that the core holding force can be maintained for a longer period of time.

ネジ部１３を加工する方法としては、先ずチャック１の前部に芯保持部１１で保持する芯５に対して若干小径の孔をキリにより形成する。その後、形成された内孔にネジ部１３をタップ加工により１次ネジ加工を行う。そして、同じタップを用いて２次タップ加工を行う。その際、ネジの切りはじめの位置を、約１／２ピッチ以下分ずらして加工する。すると、１次タップ加工で形成された凸部が部分的に削られ、凸部１４の頂部に尖部１６が形成されるとともに、凹部１５から先端までの高さが高い高尖部１６ａと、相対的に凹部から尖部１６の先端までの高さが低い低尖部１６ｂと、が長手方向に沿って交互に連続して形成される。尚、高尖部１６ａと低尖部１６ｂの高さの違いは、２次タップ加工時のネジの切りはじめの位置のずらし量で調整でき、凹部１５の底面から高尖部１６ａの先端までの高さをＸとし、凹部１５の底面から低尖部１６ｂの先端までの高さをＹとしたとき、０．５Ｘ＜Ｙ＜０．９Ｘの関係を満たすよう構成することが好ましい。また、図２の長手方向に沿った断面において、高尖部１６ａと低尖部１６ｂの内角は同じ角度で形成することが好ましく、また、その角度Ｎは３０°＜Ｎ＜７０°で形成することが好ましい。その理由は後述する。 As a method of processing the threaded portion 13, first, a hole having a slightly smaller diameter than the core 5 held by the core holding portion 11 is formed in the front portion of the chuck 1. After that, the threaded portion 13 is tapped into the formed inner hole to perform primary threading. Then, the secondary tap processing is performed using the same tap. At that time, the position where the screw starts to be cut is shifted by about 1/2 pitch or less. Then, the convex portion formed by the primary tapping process is partially scraped to form the apex 16 at the top of the convex portion 14, and the high apex 16a having a high height from the concave portion 15 to the tip. The low tip 16b, which has a relatively low height from the recess to the tip of the tip 16, is formed alternately and continuously along the longitudinal direction. The difference in height between the high-pointed portion 16a and the low-pointed portion 16b can be adjusted by the amount of deviation of the screw cutting start position during the secondary tapping, from the bottom surface of the recess 15 to the tip of the high-pointed portion 16a. When the height is X and the height from the bottom surface of the recess 15 to the tip of the low tip 16b is Y, it is preferable to satisfy the relationship of 0.5X <Y <0.9X. Further, in the cross section along the longitudinal direction of FIG. 2, it is preferable that the internal angles of the high-pointed portion 16a and the low-pointed portion 16b are formed at the same angle, and the angle N is formed at 30 ° <N <70 °. Is preferable. The reason will be described later.

具体的に、本実施形態では、高尖部１６ａの高さＸを０．０７８ｍｍ、低尖部１６ｂの高さＹを０．０５２ｍｍで形成してあり、０．５Ｘ＜Ｙ＜０．９Ｘの関係を満たしている。また、高尖部１６ａ及び低尖部１６ｂの内角Ｎは６０°で形成してある。 Specifically, in the present embodiment, the height X of the high-pointed portion 16a is 0.078 mm, the height Y of the low-pointed portion 16b is 0.052 mm, and 0.5X <Y <0.9X. Meet the relationship. Further, the internal angles N of the high-pointed portion 16a and the low-pointed portion 16b are formed at 60 °.

次に、図３を用いて、本実施形態のシャープペンシル用チャック１を使って実際に芯５を保持する状態の一例を説明する。
図３に示すように、チャック１の側面に形成した外周凹部１８に金属製のボール２を回動可能に配置する。更に、チャック１の外側にはボール２と当接するように内面にテーパー面３ａを有する締具３が配置され、シャープペンシル用チャック１の後部外段１７と締具３の内段３ｂとの間に取付時荷重５ｇ～３０ｇでコイルスプリング４を張架し、チャック１の外周凹部１８に配置されたボール２を締具３のテーパー面３ａに押圧する。すると、チャック１の芯保持部１１は締具３のテーパー面３ａとの楔作用により閉じられ芯保持部１１の高尖部１６ａにより芯５を保持する。また、チャック１の芯保持部１１により保持された芯５は、長手方向前方には楔作用が解除されてわずかな抵抗で移動できるが、長手方向後方には楔作用が働き強い力で移動が阻止される。更に、締具３の前部に駒６を圧入固着し、ボール２の外れを防止する。 Next, with reference to FIG. 3, an example of a state in which the lead 5 is actually held by using the mechanical pencil chuck 1 of the present embodiment will be described.
As shown in FIG. 3, the metal ball 2 is rotatably arranged in the outer peripheral recess 18 formed on the side surface of the chuck 1. Further, a fastener 3 having a tapered surface 3a on the inner surface is arranged on the outer side of the chuck 1 so as to come into contact with the ball 2, and is between the rear outer stage 17 of the mechanical pencil chuck 1 and the inner stage 3b of the fastener 3. The coil spring 4 is stretched with a load of 5 g to 30 g at the time of mounting, and the ball 2 arranged in the outer peripheral recess 18 of the chuck 1 is pressed against the tapered surface 3a of the fastener 3. Then, the core holding portion 11 of the chuck 1 is closed by the wedge action with the tapered surface 3a of the fastener 3, and the core 5 is held by the high pointed portion 16a of the core holding portion 11. Further, the core 5 held by the core holding portion 11 of the chuck 1 can move with a slight resistance because the wedge action is released in the front in the longitudinal direction, but the wedge action acts in the rear in the longitudinal direction and moves with a strong force. Be blocked. Further, the piece 6 is press-fitted and fixed to the front portion of the fastener 3 to prevent the ball 2 from coming off.

また、図３の芯５を保持した状態で繰り返し筆記を継続すると、芯５を保持している芯保持部１１の高尖部１６ａが徐々に摩耗し先端が丸まってくることで芯保持力が低下するが、本発明では高尖部１６ａが摩耗すると芯５と低尖部１６ｂ当接するようになるため、芯５の保持力を長期に渡って維持することが可能である。尚、前述したように、尖部１６の高さは、凹部１５の底面から高尖部１６ａの先端までの高さをＸとし、凹部の底面から低尖部１６ｂの先端までの高さをＹとしてとき、０．５Ｘ＜Ｙ＜０．９Ｘの関係を満たすようにしているため、初期には高尖部１６ａと低尖部１６ｂの高さに差があることで芯５が高尖部１６ａのみで保持され、繰り返しの使用により高尖部１６ａの先端が摩耗して丸まり芯保持力が低下しても芯保持力が筆記時の筆圧より下がる前に低尖部１６ｂで芯５を保持することで、長期に渡って芯５を確実に保持することができる。さらに、高尖部１６ａと低尖部１６ｂの内角Ｎは、３０°＜Ｎ＜７０°の関係式を満たすよう形成していることから、Ｎを３０°より大きくすることで尖部１６が尖りすぎないため高尖部１６ａ及び低尖部１６ｂの先端で芯に与えるダメージを最小限にして芯の折損を防止しつつ、７０°より小さくすることでしっかり芯を保持することができる。また、高尖部１６ａと低尖部１６ｂの内角Ｎは同じ角度で形成しているため、高尖部１６ａが摩耗して高尖部１６ａから低尖部１６ｂに芯の保持位置が移動しても芯５へのダメージや保持力の変化が少ないため、継続的に使用しても使用感の変化が小さいシャープペンシル用チャック１を提供できた。 Further, when writing is continued repeatedly while holding the core 5 of FIG. 3, the high tip portion 16a of the core holding portion 11 holding the core 5 is gradually worn and the tip is rounded, so that the core holding force is increased. However, in the present invention, when the high-pointed portion 16a is worn, the core 5 and the low-pointed portion 16b come into contact with each other, so that the holding force of the core 5 can be maintained for a long period of time. As described above, the height of the apex 16 is such that the height from the bottom surface of the recess 15 to the tip of the high apex 16a is X, and the height from the bottom surface of the recess to the tip of the low apex 16b is Y. Since the relationship of 0.5X <Y <0.9X is satisfied, the core 5 has a high-pointed portion 16a due to a difference in height between the high-pointed portion 16a and the low-pointed portion 16b at the initial stage. Even if the tip of the high-pointed portion 16a is worn and rounded due to repeated use and the core holding force is reduced, the core 5 is held by the low-pointed portion 16b before the core holding force drops below the writing pressure at the time of writing. By doing so, the core 5 can be reliably held for a long period of time. Further, since the internal angles N of the high apex portion 16a and the low apex portion 16b are formed so as to satisfy the relational expression of 30 ° <N <70 °, the apex 16 is sharpened by making N larger than 30 °. Since it is not too much, the damage to the core at the tips of the high-pointed portion 16a and the low-pointed portion 16b is minimized to prevent the core from breaking, and the core can be firmly held by making it smaller than 70 °. Further, since the internal angles N of the high-pointed portion 16a and the low-pointed portion 16b are formed at the same angle, the high-pointed portion 16a is worn and the holding position of the core moves from the high-pointed portion 16a to the low-pointed portion 16b. However, since the damage to the core 5 and the change in the holding force are small, it is possible to provide the chuck 1 for mechanical pencils in which the change in usability is small even if it is used continuously.

また、本発明は、図３の実施形態に限定されるものではなく、チャックの芯保持部外面に締具を外嵌し、締具あるいはチャックの芯保持部外面のどちらかにテーパー面を形成し、このテーパー面の楔作用によりチャックの芯保持部を閉じて芯を保持するノック式シャープペンシルに利用しても良い。 Further, the present invention is not limited to the embodiment shown in FIG. 3, and the fastener is fitted on the outer surface of the core holding portion of the chuck to form a tapered surface on either the fastener or the outer surface of the core holding portion of the chuck. However, it may be used for a knock-type mechanical pencil that closes the core holding portion of the chuck to hold the core by the wedge action of the tapered surface.

１シャープペンシル用チャック
２ボール
３締具
３ａテーパ面
３ｂ内段
４コイルスプリング
５芯
６駒
１１芯保持部
１３ネジ部
１４凸部
１５凹部
１６尖部
１６ａ高尖部
１６ｂ低尖部
１７後部外段
１８外周凹部 1 Mechanical pencil chuck 2 Ball 3 Fastener 3a Tapered surface 3b Inner stage 4 Coil spring 5 Core 6 piece 11 Core holding part 13 Threaded part 14 Convex part 15 Concave part 16 Pointed part 16a High pointed part 16b Low pointed part 17 Rear outer stage 18 Outer peripheral recess

Claims

芯保持部が複数に分割され、楔作用により当該芯保持部で芯を保持するシャープペンシル用チャックであって、
前記芯保持部に凹部と凸部が連続的に形成されたネジ部を備え、前記凸部の頂部に尖部が形成され、
長手方向に沿った断面において、前記凸部は、前記凹部の底面から前記尖部の先端までの相対的な高さが高い高尖部と低い低尖部とにより交互に連続して形成されていることを特徴とするシャープペンシル用チャック。 A mechanical pencil chuck in which the core holding portion is divided into a plurality of parts and the core is held by the core holding portion by a wedge action.
The core holding portion is provided with a threaded portion in which a concave portion and a convex portion are continuously formed, and a sharp portion is formed on the top of the convex portion.
In a cross section along the longitudinal direction, the convex portion is formed alternately and continuously by a high sharp portion having a high relative height from the bottom surface of the concave portion to the tip of the peak and a low sharp portion having a low relative height. A chuck for mechanical pencils, which is characterized by being present.

前記凹部の底面から高尖部の先端までの高さをＸとし、前記凹部の底面から低尖部の先端までの高さをＹとしてとき、０．５Ｘ＜Ｙ＜０．９Ｘの関係を満たすことを特徴とする請求項１に記載のシャープペンシル用チャック。 When the height from the bottom surface of the recess to the tip of the high tip is X and the height from the bottom of the recess to the tip of the low tip is Y, the relationship of 0.5X <Y <0.9X is satisfied. The chuck for a mechanical pencil according to claim 1.

長手方向に沿った断面において、前記高尖部の内角と前記低尖部の内角とが同一の角度であることを特徴とする請求項１または２に記載のシャープペンシル用チャック。 The chuck for a mechanical pencil according to claim 1 or 2, wherein the internal angle of the high-pointed portion and the internal angle of the low-pointed portion are the same in a cross section along the longitudinal direction.

前記高尖部及び前記低尖部の内角をＮとしたとき、３０°＜Ｎ＜７０°を満たすことを特徴とする請求項３に記載のシャープペンシル用チャック。 The chuck for a mechanical pencil according to claim 3, wherein when the internal angles of the high-pointed portion and the low-pointed portion are N, 30 ° <N <70 ° is satisfied.

少なくとも前記芯保持部の表面に無電解メッキ層が形成されていることを特徴とする請求項１ないし４の何れか一項に記載のシャープペンシル用チャック。 The chuck for a mechanical pencil according to any one of claims 1 to 4, wherein an electroless plating layer is formed at least on the surface of the core holding portion.