JP2009061630A - Shaft tube structure of writing instruments - Google Patents

Abstract

An object of the present invention is to provide a shaft cylinder structure for a writing instrument that has a structure in which it is difficult for the shaft cylinder member and the end member to be attached by screwing and the appearance of the writing instrument does not deteriorate due to the structure. .
A shaft tube structure of a writing instrument in which an end member is detachably screwed to an end portion of a shaft tube member, wherein a male screw portion is formed on an outer peripheral surface of the end portion of the shaft tube member, and the end member A female threaded portion that engages with the male threaded portion of the shaft tube member is formed on the inner peripheral surface of the shaft member, and a locking groove that locks the O-ring is formed at an inner position from the female threaded portion. A shaft cylinder structure of a writing instrument, characterized in that an O-ring locked in a locking groove of an end member comes into contact with the end of the shaft cylinder member and repels when screwed into the cylinder member.
[Selection] Figure 5

Description

  The present invention relates to a shaft tube structure of a writing instrument in which an end member is detachably screwed to an end portion of a shaft tube member.

  2. Description of the Related Art Conventionally, in a cylindrical structure of a writing instrument, for example, a cylindrical structure of a writing instrument in which a tail crown is attached to the rear end side of the writing instrument body or a head crown is attached to the distal end side of the cap body is well known. The end members, which are the tail crown and the head crown, are generally attached to the shaft tube member, which is the shaft tube main body or the cap body, by fitting or screwing. In particular, in a writing instrument having a structure in which an eraser is inserted into the end of the barrel body and an end member is mounted so as to cover the eraser, the end member is attached and detached when using the eraser. Many attachment methods by screwing are employed so as to prevent the members from loosening or falling off.

Further, in order to make the mounting by screwing more difficult to be detached, for example, those adopting a structure as shown in the drawings of the prior document 1 and the prior document 2 are widely used in the market. In the structure of the prior art document 1, the O-ring, which is an elastic body, is locked and disposed in the groove formed on the outer peripheral surface of the rear end of the rear shaft. The structure is such that the looseness of the tail crown can be prevented by repelling an O-ring disposed on the rear shaft at the front end of the tail crown. In the structure of the prior art document 2, when a protrusion is provided on the large cap, a protrusion corresponding to the protrusion of the large cap is provided on the small cap that is screwed to the end of the large cap, and the small cap is screwed on the large cap. In addition, the convex portion of the small cap can overcome the protrusion of the large cap to prevent loosening.
JP 2005-161829 A JP 2002-362208 A

  However, in the structure of the prior art document 1, when the tail cap is removed from the rear shaft, the O-ring is exposed to the outside, so that the O-ring is likely to be damaged or dropped out, and an O-ring made of an elastic body is formed. By exposing, the sense of quality of the writing instrument may be reduced. Moreover, in the structure of the prior art document 2, it is necessary to form protrusions and convex portions on the outer surface of the large cap and the inner surface of the small cap, and a method other than injection molding the large cap and the small cap with a resin material, For example, it is difficult to form metal materials by cutting.

  In view of these problems, the present invention provides a structure for a writing instrument shaft cylinder in which the attachment of the shaft cylinder member and the end member is difficult to be removed and the appearance of the writing instrument does not deteriorate due to the structure. The purpose is to do.

The present invention
“1. A writing tube shaft structure in which an end member is detachably screwed to an end portion of a shaft tube member, and a male screw portion is formed on an outer peripheral surface of the end portion of the shaft tube member, and the end portion A female screw portion that engages with the male screw portion of the shaft tube member is formed on the inner peripheral surface of the member, and a locking groove that locks the O-ring is formed at an inner position from the female screw portion. A shaft cylinder of a writing instrument characterized by a structure in which an O-ring locked in a locking groove of the end member comes into contact with an end of the shaft cylinder member and repels when the member is screwed to the shaft cylinder member Construction.
2. The shaft cylinder has a front shaft member and a rear shaft member. By rotating the rear shaft member with respect to the front shaft member, the tip of the writing body accommodated in the shaft cylinder is moved to the tip of the shaft cylinder. 2. The writing instrument according to claim 1, wherein the writing instrument is a shaft of a rotary feeding type writing instrument structured so as to protrude from an opening, and the end member is a tail crown screwed into a rear end of the rear shaft member. Shaft tube structure. Is.

  The shaft cylinder structure of the writing instrument of the present invention, when the end member is screwed to the end of the shaft cylinder member, the O-ring locked to the end member is in contact with the end of the shaft cylinder member and repels. The screw connection between the shaft tube member and the end member is difficult to come off. In addition, since the O-ring is located inside the end member, even when the O-ring is made of an elastic body made of silicon or urethane, the writing instrument does not deteriorate in appearance, and the O-ring is also the end member. Because it is inside, the O-ring is not easily damaged, and the end of the shaft tube member is pressed in the direction to push the O-ring in the end member into the back, preventing the O-ring itself from falling off. it can.

  Next, examples of the shaft tube structure of the writing instrument of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. The writing instrument of this example, the shaft cylinder has a front shaft and a rear shaft, and by rotating the rear shaft relative to the front shaft, the writing tip of the mechanical pencil unit and the ball pen refill accommodated in the shaft tube, A description will be given of a rotary paying-out type composite writing instrument having a structure in which it is projected and retracted from the tip opening of the shaft cylinder. In addition, the same code | symbol is used about the same member and the same component in a figure. Also, the side with the writing tip is expressed as the front, and the opposite direction is expressed as the rear.

  FIG. 1 shows a rotary payout-type composite writing instrument of this embodiment. The writing instrument 1 includes a front shaft member 2, a rear shaft member 3 that rotates with respect to the front shaft member 2, and a tail crown 4 that is disposed at a rear end portion 3 a of the rear shaft member 3. A rotating cam mechanism (not shown) provided in the shaft cylinder 5 is operated by rotating the rear shaft member 3 with respect to the front shaft member 2, and as shown in FIG. The tip writing 6 of the mechanical pencil unit housed in 5 and the writing tip (not shown) of the ballpoint pen refill can be projected and retracted from the tip opening 2 a of the front shaft member 2. The lead core 7 can be fed out from the writing tip 6 of the mechanical pencil unit by advancing the rear shaft member 3 relative to the front shaft member 2 with the tip 6 of the mechanical pencil unit protruding. A clip 8 is attached to the rear of the rear shaft member 3.

  FIG. 2 is a view showing a state in which the tail crown is removed from the rear shaft member. As shown in FIG. 2, a small diameter portion 3b is provided in the rear end portion 3a of the rear shaft member 3, and a male screw portion 3c is formed on the outer peripheral surface of the small diameter portion 3b. Further, an eraser 9 for erasing the handwriting written with the lead core 7 is inserted into the rear end opening 3 d of the rear shaft member 3. FIG. 3 is a cross-sectional view of a part of FIG. 2 and shows the state in which the aforementioned eraser 9 is removed from the rear end opening 3d for easy understanding. As shown in FIG. 3, a female screw portion 4 b is formed on the inner peripheral surface of the front end opening 4 a of the tail crown 4. The female screw portion 4b is detachably engaged with a male screw portion 3c formed on the rear shaft member 3. Further, a locking groove 4c is formed circumferentially at a position inward from the female screw portion 4b, and the O-ring 10 is locked to the locking groove 4c. FIG. 4 is a partial end view of FIG. The locking groove 4c formed in the tail crown 4 is similar to the front wall 4d on the female screw portion 4b side, the side wall 4e suspended from the front wall 4d, and the rear wall 4e from the rear end. The rear wall 4f is orthogonal to the axial direction. In this embodiment, the rear wall 4f protrudes toward the axial center side from the front wall 4d with respect to the side wall 4e of the tail crown 4. The O-ring 10 is fixed to the locking groove 4c by locking more than half of its cross section.

  FIG. 5 is a cross-sectional view of the main part in a state where the tail crown is screwed to the rear end of the rear shaft member. FIG. 6 is a partial end view of FIG. In this embodiment, as shown in FIG. 5, the O-ring 10 is in contact with the rear end 3 a of the rear shaft member 3 when the tail crown 4 is screwed to the rear end 3 a of the rear shaft member 3. . Further, as shown in FIG. 6, the O-ring 10 is deformed by being pushed by the rear end portion 3 a of the rear shaft member 3 in a state where the tail crown 4 is screwed to the rear shaft member 3. However, the rear end portion 3a of the rear shaft member 3 was ejected forward (downward in the drawing) to prevent the tail crown 4 from loosening. In this embodiment, the rear wall 4f of the locking groove 4c of the tail crown 4 protrudes to the axial center side. Therefore, even when the O-ring 10 is pushed backward by the rear shaft member 3, the rear wall 4f. Serves as a support for the O-ring 10 and prevents the O-ring 10 from being displaced inward (upward in the drawing) of the tail crown 4. In this embodiment, as shown in FIG. 2, even when the tail crown 4 is removed from the rear shaft member 3, the O-ring 10 is not exposed to the outside. Never happened.

  Moreover, since the writing instrument of the present embodiment is a rotary-drawing-type composite writing instrument as described above, when the writing tip of the mechanical pencil unit or the ballpoint pen refill is retracted at the time of use, the front shaft member 2 shown in FIG. Although the rear shaft member 3 is rotated, the tail crown 4 is not loosened even when the finger touches the tail crown 4 during the rotation operation of the rear shaft member 3.

  FIG. 7 is a view of a comparative example, which has a structure that has been widely used in the market as shown in the above-mentioned prior art 1 figure. FIG. 8 is a partial end view of the state in which the tail crown of FIG. 7 is screwed to the rear shaft member. In the comparative example, a circumferential locking groove 30d is formed in front of the male screw portion 30c formed in the rear end portion 30a of the rear shaft member 30, and the O-ring 10 is locked in the locking groove 30d. I am letting. Further, the O-ring 10 is pressed against the front end of the tail crown 40 by screwing the female screw portion 40 b formed on the inner peripheral surface of the front end opening 40 a of the tail crown 40 with the male screw portion 30 c of the rear shaft member 30. As a result, the O-ring 10 repels the front end of the tail crown 40 backward (upward in the drawing) to prevent the tail crown 40 from loosening. Since other points are the same as those of the embodiment of the present invention, description thereof is omitted. As shown in FIG. 7, in the comparative example, the O-ring 10 is exposed to the outside when the tail cap 40 is removed from the rear barrel 30, so that the O-ring 10 is easily damaged and looks good. It got worse. Further, in the comparative example, a circumferential covering portion 40c is provided at the front end of the tail crown 40 so that the O-ring 10 is not visible when the tail crown 40 is screwed to the rear shaft member 30. When the front end becomes thick and the outer diameter of the tail crown 4 of the present embodiment and the tail crown 40 of the comparative example are the same, the inner diameter of the tail crown 40 of the comparative example is reduced as a result, and the rear It has become necessary to reduce the outer diameter of an eraser (not shown) that is inserted into the shaft member 30.

  The shaft tube structure of the writing tool according to the present invention can be used not only as a shaft tube for a writing tool but also for a shaft tube of a cosmetic tool, an applicator, or the like.

It is a rotation payout type compound writing instrument of a present Example. It is a figure of the state which removed the tail crown from the rear shaft member. FIG. 3 is a cross section of a part of FIG. FIG. 4 is a partial end view of FIG. 3. It is the figure which made the principal part the cross section in the state which screwed the tail crown to the rear-end part of the rear-shaft member. FIG. 6 is a partial end view of FIG. 5. It is a figure of a comparative example. FIG. 8 is a partial end view of a state in which the tail cap of FIG. 7 is screwed to the rear shaft member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Writing instrument, 2 ... Front shaft member, 2a ... Tip opening part,
3 ... rear shaft member, 3a ... rear end part, 3b ... small diameter part,
3c ... male screw part, 3d ... rear end opening,
4 ... tail crown, 4a ... front end opening, 4b ... female screw,
4c ... locking groove, 4d ... front wall, 4e ... side wall, 4f ... rear wall,
5 ... Shaft tube,
6 ... writing tip, 7 ... lead core,
8 ... Clip, 9 ... Eraser,
10 ... O-ring.

Claims (2)

A shaft tube structure of a writing instrument in which an end member is detachably screwed to an end portion of a shaft tube member, wherein a male screw portion is formed on an outer peripheral surface of the end portion of the shaft tube member, A female threaded portion that engages with the male threaded portion of the shaft tube member is formed on the peripheral surface, and a locking groove for locking the O-ring is formed at an inner position from the female threaded portion. A shaft cylinder structure of a writing instrument, characterized in that, when screwed into the shaft cylinder member, an O-ring locked in a locking groove of the end member is elastically in contact with an end of the shaft cylinder member. The shaft cylinder has a front shaft member and a rear shaft member. By rotating the rear shaft member with respect to the front shaft member, the tip of the writing body accommodated in the shaft cylinder is moved to the tip of the shaft cylinder. 2. The shaft of a rotary paying-out type writing instrument structured so as to be projected and retracted from an opening, wherein the end member is a tail crown screwed into a rear end of the rear shaft member. Shaft structure of writing instruments.

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