JP2011121299A - Writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a writing utensil that can stably hold a refill with an ink storing tube in a barrel. <P>SOLUTION: The writing utensil 1 includes: a barrel 10 having a front shaft 13 and a rear shaft 14; a refill 20 with an ink storing tube 23 to be housed in the barrel 10; and a tail plug 30 installed in the rear end of the ink storing tube 23. In the inner peripheral face on the rear end side of the rear shaft 14, a plurality of standing pieces 14a projectingly provided along the shaft direction are intermittently formed in the circumferential direction. On one end side of the standing piece 14a, a difference-in-level part 14a1 is formed having a height diminishing from the inner peripheral face and, in addition, a tapered part 14a2 is provided extending from the difference-in-level part 14a1 in the tip end direction. The standing pieces 14a are such that at least the difference-in-level part 14a1 comes in contact with the rear end of the tail plug 30 and that any of the tapered part 14a2 of the plurality of standing pieces 14a is in contact with a thick part 30b1 of the tail plug 30. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a writing instrument, for example, a writing instrument in which an ink storage tube for storing ink is accommodated inside a shaft tube.

A writing instrument typified by a ballpoint pen is generally composed of a shaft cylinder constituting the exterior body, and a refill made of a writing chip and an ink storage tube accommodated in the shaft cylinder. According to this configuration, there is a problem that slight dimensional variations occur in the axial direction between the refill and the shaft cylinder that accommodates the refill.
In order to eliminate the dimensional variation, for example, Patent Document 1 discloses a writing instrument having a configuration in which a tail plug is attached to the rear end portion of the ink storage tube and the rear end portion of the tail plug is an elastic deformation portion. It has been proposed (for example, Patent Document 1).

Here, the structure of the writing instrument described in Patent Document 1 will be described with reference to FIG.
As shown in the figure, the writing instrument has a shaft cylinder formed by a front shaft 103 and a rear shaft 104, and a plurality of upright pieces 104e are intermittently formed in the circumferential direction on the inner surface of the rear shaft 104 along the axial direction. ing.
Further, a tail plug 108 is attached to the rear end side of the ink storage tube 106 constituting the refill. Further, on the rear end side of the tail plug 108, a cylindrical body portion 108b in which thick portions 108b1 and thin portions 108b2 are alternately formed along the circumferential direction is provided.

Further, a tapered surface 104f is formed at the front end portion of each of the above-mentioned standing pieces 104e, and when the rear shaft 104 is screwed to the front shaft 103, the tapered surface 104f is attached to the ink storage tube 106. It acts to abut against the cylindrical body portion 108b (inclined portion 108b1) of the attached tail plug 108 to give elastic deformation to the cylindrical body portion 108b.
That is, with the above configuration, when the tapered surface 104f of the upright piece 104e formed on the inner wall surface of the rear shaft 104 abuts on the rear end portion of the tail plug 108, the rear end portion of the tail plug 108 has a diameter thereof. As a result, the thin-walled portion 108b2 is elastically deformed, and the rear shaft 104 holds the refill to which the tail plug 108 is attached.
As a result, the dimensional variation between the shaft cylinder and the refill is absorbed, and the refill is prevented from moving in the axial direction.

Japanese Patent Laid-Open No. 2005-74980

However, the above-described conventional writing instruments have the following technical problems.
Specifically, the above-described prior art writing instrument (see FIG. 10) includes a plurality of upright pieces 104e formed on the rear shaft 104 with tapered portions 104f, and a cylindrical portion 108b of the tail plug 108 attached to the refill (see FIG. 10). There is a technical problem that the contact position with the thick portion 108b1) is not stable, and the refill may not be held in a stable state.
In particular, when the width of the upright piece 104e is small (narrow), the contact position between the cylindrical body portion 108b and the tapered portion 104f of the upright piece 104e is not stable.
In order to deal with the above technical problem, a method of increasing the number of upright pieces (more than twice the number of thick parts) can be considered, but increasing the number of upright pieces increases the mold release resistance in the molding process. Becomes larger, which causes another technical problem of increasing the molding time.
Further, in order to cope with the above technical problem, there is a method of suppressing the cylindrical portion of the tail plug on the entire circumferential surface by forming a thickness of the rear shaft substantially uniformly without forming a standing piece on the rear shaft. According to this method, when the shaft cylinder is made thick, the shaft surface becomes sinked (concave), the appearance is lost, and defective products are generated when the shaft is transferred.

  The present invention has been made in order to solve the above technical problem, and an object of the present invention is to provide a writing instrument that can stably hold a refill including an ink storage tube in a shaft cylinder. There is.

In order to solve the above problems, the present invention provides a shaft tube, a refill including an ink storage tube accommodated in the shaft tube, and a tail plug attached to a rear end portion of the ink storage tube. A plurality of upright pieces projecting along the axial direction are formed intermittently in the circumferential direction on the inner peripheral surface of the rear end side of the shaft tube, and the writing tool is provided on one end side of the upright piece. Is formed with a stepped portion having a small height from the inner peripheral surface, and further provided with a tapered portion extending from the stepped portion toward the distal end, and the standing piece has at least the stepped portion as the tail plug. And a taper portion of any of the plurality of upright pieces is in contact with the rear end side of the tail plug.
Further, the tail plug is formed with a vent hole penetrating both ends, and on the rear end side, thin portions and thick portions are alternately formed along the circumferential direction around the vent hole, and the taper is formed. It is desirable that the portion is in contact with the thick portion.

Thus, in the present invention, a plurality of upright pieces projecting along the axial direction are formed intermittently in the circumferential direction on the inner peripheral surface of the rear end side of the shaft tube, and a step portion is formed at one end of the upright piece. And a tapered portion. The standing piece has at least the stepped portion in contact with the rear end side of the tail plug, and the tapered portion of any of the plurality of standing pieces comes into contact with the rear end side of the tail plug. Yes.
With the above configuration, the stepped portion of the upright piece intermittently formed in the circumferential direction on the inner peripheral surface of the shaft tube abuts on the rear end side of the tail plug, so that the shaft tube 10 can be stably held.
That is, according to the present invention, the standing piece is provided with a stepped portion that comes into contact with the rear end side of the tail plug, so that the writing tool of the prior art in which the tail plug is pressed only by the tapered portion (see FIG. 10). In comparison, the refill fitted with the tail plug can be stably held in the shaft tube.

Further, it is desirable that a slope portion is formed between adjacent standing pieces on the inner peripheral surface on the rear end side of the shaft cylinder, and the standing piece and the slope portion are in contact with the tail plug.
Thus, the writing instrument of the present invention is a rear end side of the tail plug attached to the refill in which the standing pieces and the slope portions are alternately arranged along the circumferential direction of the inner peripheral surface of the rear end side of the shaft tube. In addition, since the upright piece and the inclined surface are in contact with each other, the refill can be reliably positioned and held on the shaft center of the shaft tube.

Further, it is desirable that five upright pieces are formed on the inner peripheral surface of the rear end side of the shaft tube, and three thick portions are formed on the tail plug.
As a result of repeated research by the inventors of the present application, it has been found that if the number of the upstanding pieces is more than 5, the release resistance in the molding process increases and the molding time increases. Furthermore, it was found that if the number of standing pieces is less than twice the number of thick parts of the tail plug, it is possible to prevent the occurrence of sink marks (concaves) on the surface of the shaft tube.

Moreover, it is desirable that at least two of the five standing pieces and one inclined surface are in contact with the thick portion of the tail plug.
In this configuration, when there are five standing pieces, if at least two standing pieces and one inclined surface are in contact with the thick part of the tail plug, This is because the refill can be positioned and held on the axial center of the cylinder.

  ADVANTAGE OF THE INVENTION According to this invention, the writing instrument which can hold | maintain the refill provided with the ink storage tube in the shaft cylinder in the stable state can be provided.

It is the schematic diagram which showed the external appearance of the writing instrument of embodiment of this invention. It is a longitudinal cross-sectional view of the writing instrument of embodiment of this invention. It is sectional drawing of the rear axis | shaft which comprises the axial cylinder of embodiment of this invention. It is BB sectional drawing of FIG. It is a perspective view of the tail plug attached to the refill of the writing instrument of embodiment of this invention. It is a top view of the tail plug attached to the refill of the writing instrument of embodiment of this invention. It is a front view of the tail plug attached to the refill of the writing instrument of embodiment of this invention. It is the schematic diagram which showed the AA cross section of FIG. It is sectional drawing which expanded and showed the rear-end part of the writing instrument of embodiment of this invention. It is sectional drawing which expanded and showed the rear-end part of the writing instrument of the prior art.

Hereinafter, a writing instrument according to an embodiment of the present invention will be described with reference to the drawings.
First, a schematic configuration of a writing instrument according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a schematic view showing an appearance of a writing instrument according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the writing instrument according to the embodiment of the present invention. In the following description, a ballpoint pen is shown as the writing instrument 1, but this is merely an example.

As shown in FIGS. 1 and 2, the writing instrument (ballpoint pen) 1 of the present embodiment includes a shaft cylinder 10 that constitutes an outline of the writing instrument 1, a refill 20 accommodated in the shaft cylinder 10, and a rear end of the refill 20. And a cap (not shown) that is detachably fitted to the tip of the shaft tube 10.
Here, the shaft cylinder 10 is formed of, for example, a synthetic resin (for example, PC (polycarbonate)) or the like, and has a hollow cylindrical front shaft 13 that is penetrated at both ends, and a base 12 that is supported by a tip portion of the front shaft 13. And a hollow cylindrical rear shaft 14 detachably attached to the front shaft 13 behind the front shaft 13.
The refill 20 includes a writing chip 22 and an ink storage tube 23, and the writing chip 22 and the ink storage tube 23 are connected by a joint member 24 interposed therebetween. Ink 25 is stored in the ink storage tube 23.

The refill 20 is housed in the cylinder 10 with the tail plug 30 attached to the rear end thereof, and the tip of the writing tip 22 is opened from the opening formed in the tip of the base 12. It is designed to protrude.
In addition, the rear shaft 14 has a plurality of upright pieces 14a projecting along the axial direction on the inner peripheral surface on the rear end side thereof at predetermined intervals in the circumferential direction (the upright pieces 14a are formed intermittently in the circumferential direction). The standing piece 14a comes into contact with the rear end side of the tail plug 30 attached to the refill 20.
Hereinafter, each structure of the writing instrument 1 is demonstrated concretely. Since the refill 20 is the same as a known one, detailed description thereof is omitted.

First, the configuration of the shaft tube 10 will be described with reference to FIG. 2 and FIGS. 3 and 4 described above.
FIG. 3 is a cross-sectional view of the rear shaft constituting the shaft tube of the present embodiment. 4 is a cross-sectional view taken along the line BB in FIG.

Specifically, as shown in FIG. 2, in the shaft tube 10 of the present embodiment, the base 12 and the tip shaft 13 are configured as an integral part. The base 12 is formed such that the outer shape is reduced compared to the front shaft 13 and further the outer shape becomes smaller toward the tip.
In the present embodiment, the base 12 and the tip shaft 13 are configured as an integral part, but the present invention is not particularly limited thereto. For example, the base 12 and the front shaft 13 may be configured separately, and the base 12 may be detachably locked to the front end portion of the front shaft 13.

Further, the front shaft 13 has a threaded portion 13c formed on the outer wall surface at the rear end thereof.
Further, the rear shaft 14 is formed in a hollow cylindrical shape, the front end portion thereof is opened, the rear end portion thereof is closed, and the inner wall surface of the front end portion is further screwed into the screw portion 13c of the front shaft 13. A portion 14c is formed.
With the above configuration, the screw shaft 13c formed on the inner wall surface of the rear shaft 14 is screwed into the screw portion 13c formed on the outer wall surface of the rear end portion of the front shaft 13, whereby the rear shaft 14 is moved to the front shaft 13. It can attach to the rear-end part so that attachment or detachment is possible.

  Further, as shown in FIGS. 3 and 4, the rear shaft 14 has a plurality of upright pieces 14a projecting along the axial direction (s direction shown in FIG. 3) on the inner peripheral surface on the rear end side. In addition to being formed at predetermined intervals in the direction, a slope portion 14b is formed between adjacent upright pieces 14a along the axial direction. That is, on the inner surface on the rear end side of the rear shaft 14, five standing pieces 14a and five inclined surfaces 14b are alternately formed along the circumferential direction.

Further, as shown in FIG. 3, at one end side (lower end side shown in FIG. 3) of the upright piece 14a, a step portion 14a1 that is substantially perpendicular to the axial direction, and a taper that extends from the step portion 14a1 in the axial direction. A portion 14a2 is formed.
Specifically, a stepped portion 14a1 having a small height from the inner peripheral surface of the rear shaft 14 is formed on one end side (lower end side shown in FIG. 3) of the upright piece 14a, and further, the stepped portion 14a1. A taper portion 14a2 extending in the axial direction is provided. The taper portion 14a2 has a height dimension from the inner peripheral surface that is smaller toward the tip (lower end shown in FIG. 3).
The step portion 14a1 is substantially perpendicular to the axial direction, but is not particularly limited thereto. The step portion 14a1 only needs to be shaped so as to be opposed to the rear end portion of the tail plug 30 attached to the refill 20 accommodated in the shaft tube 10.

  Then, when the refill 20 is accommodated in the shaft tube 10, the refill 20 (refill 20 with the tail plug 30 attached) is inserted into the tube from the rear end of the front shaft 13 with the writing tip 22 facing the head, After that, the screw portion 14 c formed on the inner wall surface on the front end side of the rear shaft 14 is screwed into the screw portion 13 c of the front shaft 13, whereby the refill is accommodated in the shaft tube 10.

Next, the structure of the tail plug 30 is demonstrated using FIG. 2 mentioned above and FIGS. 5-7.
FIG. 5 is a perspective view of the tail plug attached to the refill of the writing instrument according to the embodiment of the present invention. FIG. 6 is a plan view of a tail plug attached to the refill of the writing instrument according to the embodiment of the present invention. FIG. 7 is a front view of a tail plug attached to the refill of the writing instrument according to the embodiment of the present invention.

Specifically, the tail plug 30 includes a cylindrical portion 30a (see FIGS. 5 and 7) having an outer diameter that can be fitted into an inner diameter portion of the ink storage tube 23 (see FIG. 2) constituting the refill 20, and an ink. A cylindrical body 30b (see FIGS. 5 and 7) having an outer diameter substantially equal to the outer diameter of the housing tube 23 is provided.
Further, the tail plug 30 is formed with a vent hole 30g penetrating along the axis so as to allow the inside and outside of the ink containing tube 23 to vent.
The tail plug 30 is preferably formed of a synthetic resin material having a relatively elastic force such as polypropylene.

Further, as shown in FIGS. 5 and 6, the cylindrical portion 30b formed on the rear end side of the tail plug 30 has a thick portion 30b1 and a thin wall along the circumferential direction centering on the vent hole 30g. The portions 30b2 are alternately formed. Further, the thick portions 30b1 and the thin portions 30b2 are alternately formed at equal intervals (120 degree intervals) (three thick portions 30b1 and three thin portions 30b2 are formed).
With this configuration, when the upright piece 14a formed on the inner wall surface of the rear shaft 14 comes into contact with the rear end portion of the tail plug 20, the rear end portion of the tail plug 30 is subjected to the action of reducing its diameter. As a result, the thin-walled portion 30b1 is elastically deformed to generate a deflection that is slightly triangular from a substantially circular state. In addition, the structure of the tail plug 30 of this embodiment is the same as what was described in the patent document 1 mentioned above.

Next, when the refill 20 to which the tail plug 30 is attached is accommodated in the shaft cylinder 10, the standing piece 14 a and the slope portion 14 b formed on the rear end side of the shaft cylinder 10 (rear shaft 14), the tail plug The relationship with 30 cylindrical body portions 30b will be described with reference to FIG. 2 described above, and FIGS.
FIG. 8 is a schematic diagram showing the AA cross section of FIG. Moreover, FIG. 9 is the schematic diagram which expanded and showed the cross section of the rear-end side of the writing instrument of embodiment of this invention.

Specifically, as shown in FIG. 9, when the refill 20 is accommodated in the shaft tube 10 (that is, the refill 20 with the tail plug 30 is inserted into the tube of the tip shaft 13, and the screw of the tip shaft 13 is inserted. When the threaded portion 14c of the rear shaft 14 is screwed onto the portion 13c), among the plurality of standing pieces 14a, the taper of the standing piece 14a disposed opposite to the thick portion 30b1 of the tail plug 30 The part 14a2 comes into contact with the outer peripheral side surface of the tail plug 30 (thick part 30b1).
In addition, the taper part 14a2 of the standing piece 14a arranged opposite to the thin part 30b2 of the tail plug 30 is similar to the above-described prior art shown in FIG. 10 in the tail plug 30 (thin part 30b2). It does not come into contact.
Further, when the refill 20 is accommodated in the shaft tube 10, the stepped portion 14 a 1 of the standing piece 14 a is in contact with at least the rear end of the tail plug 30.

As described above, in this embodiment, when the stepped portion 14a1 is formed in the standing piece 14a and the refill 20 is accommodated in the shaft tube 10, the stepped portion 14a1 is at least in contact with the rear end portion of the tail plug 30. It is configured to touch.
Therefore, according to the present embodiment, the upright piece 14a (the upright piece 14a arranged opposite to the thin-walled portion 30b2) that is not disposed opposite to the thick portion 30b2 of the tail plug 30 is also provided in the step portion. Since 14a1 comes into contact with the tail plug 30 (to hold the tail plug 30), the refill 20 to which the tail plug 30 is attached can be held in a stable state.

Furthermore, as shown in FIG. 8, the writing instrument 1 of the present embodiment has standing pieces 14 a and slope portions 14 b alternately formed along the circumferential direction of the inner peripheral surface on the rear end side of the rear shaft 14 ( 8), the upright piece 14a and the inclined surface portion 14b come into contact with the rear end side of the tail plug 30 attached to the refill 20.
That is, according to the configuration of the rear shaft 14 of the present embodiment, the upright piece 14a and the inclined surface portion 14b come into contact with each other along the outer periphery of the tail plug 30 attached to the rear end of the refill 20. The refill 20 can be reliably positioned and held on the axial center of the cylinder 10.

In the present embodiment, five upright pieces 14a of the rear shaft 14 are formed and three thick portions 30b1 of the tail plug 30 are formed. The reason for this configuration is as follows.
Specifically, as a result of repeated research by the inventors of the present application, it has been found that when the number of the upstanding pieces 14a is more than five, the release resistance in the molding process is increased and the molding time is increased.
In addition, as a result of the research, if the number of upright pieces 14a formed on the rear shaft 14 is less than twice the number of the thick portions 30b1 of the tail plug 30, sink marks (concaves) are generated on the surface of the shaft tube 10. It was found that can be prevented.
As a result, in this embodiment, the number of the upright pieces 14a of the rear shaft 14 is five, and the thick portion 30b1 of the tail plug 30 is three.

Further, in the present embodiment, at least two of the five standing pieces 14 a and the one inclined surface 14 b are in contact with the thick portion 30 b 1 of the tail plug 30. .
If there are five upright pieces, this configuration is configured so that at least two upright pieces and one inclined surface portion are in contact with the thick portion 30b1 of the tail plug 30. This is because the refill 20 can be positioned and held on the axial center of the shaft tube 10.

As described above, according to the configuration of the writing instrument 1 of the present embodiment, when the refill 20 with the tail plug 30 attached is inserted into the rear shaft 14 on which the standing piece 14a is formed (that is, the rear shaft 14). When the refill 20 is accommodated), the refill 20 can be positioned and held in a stable state on the shaft center of the shaft tube 10. As a result, according to the present embodiment, bending of the refill 20 is prevented.
Moreover, according to this embodiment, the protruding dimension of the writing chip 22 from the base 12 can be stabilized by the above configuration. Therefore, for example, the writing instrument 1 of the present embodiment is applied to a seal-type ballpoint pen that seals the nib (a ballpoint pen of a type in which a seal member such as rubber is provided inside the cap and the nib is sealed by the seal member). In this case, it is possible to effectively prevent the occurrence of a sealing failure.

Moreover, since the writing instrument 1 of this embodiment is comprised as mentioned above, even when it assembles with an automatic machine, since the shift | offset | difference from the axial center of the refill 20 is prevented, generation | occurrence | production of inferior goods is suppressed. The That is, the productivity of the writing instrument 1 is improved by adopting the configuration of the writing instrument 1 of the present embodiment.
In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible within the range of the summary.

  For example, in the above-described embodiment, the writing instrument 1 is an example of a ballpoint pen. The present invention can be applied.

1 Writing instrument 10 Shaft tube 12 Cap (shaft tube)
13 Lead shaft (shaft tube)
13c Screw part (front shaft (shaft cylinder))
14 Rear shaft (shaft tube)
14a Standing piece (rear shaft (shaft cylinder))
14a1 Stepped part (standing piece (rear shaft (shaft cylinder)))
14a2 Tapered part (standing piece (rear shaft (shaft cylinder)))
14b Slope (rear shaft (shaft cylinder))
14c Screw part (rear shaft (shaft cylinder))
20 Feel 22 Writing tip (Refill)
23 Ink storage tube (refill)
24 Joint member (refill)
25 ink (refill)
30 Tail plug 30a Cylindrical part (tail plug)
30b Tube part (tail plug)
30b1 Thick part (Cylinder part (tail plug))
30b2 Thin part (cylinder part (tail plug))
30g Vent (tail plug)

Claims (5)

A writing instrument comprising a shaft tube, a refill provided with an ink storage tube accommodated in the shaft tube, and a tail plug attached to a rear end portion of the ink storage tube,
A plurality of upright pieces projecting along the axial direction are intermittently formed in the circumferential direction on the inner peripheral surface of the rear end side of the shaft cylinder,
On one end side of the upright piece, a stepped portion having a small height dimension from the inner peripheral surface is formed, and further, a tapered portion extending from the stepped portion in the distal direction is provided,
In the standing piece, at least the stepped portion is in contact with the rear end side of the tail plug, and any one of the plurality of standing pieces is in contact with the rear end side of the tail plug. Writing instrument. The tail plug is formed with a vent hole penetrating both ends, and the thin wall portion and the thick wall portion are alternately formed along the circumferential direction around the vent hole on the rear end side of the tail plug,
The writing instrument according to claim 1, wherein the tapered portion is configured to contact the thick portion. A slope portion is formed between adjacent standing pieces on the inner peripheral surface on the rear end side of the shaft cylinder,
The writing instrument according to claim 1, wherein the standing piece and the slope portion are in contact with the tail plug.   5. The writing instrument according to claim 3, wherein five standing pieces are formed on an inner peripheral surface of the rear end side of the shaft tube, and three thick portions are formed on the tail plug.   5. The writing instrument according to claim 4, wherein at least two of the five standing pieces and one inclined surface are in contact with a thick portion of the tail plug.

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