Cap of a writing instrument

Abstract

To provide a head crown of a writing utensil which has good moldability in injection molding, finely molds an uneven part on an outer peripheral surface, and forms a gate mark at a position where a finger is hardly abutted.SOLUTION: A head crown of a writing utensil includes a head crown body 11 and a clip part 13 connected to one end of the head crown body 11 via a connecting part 14, in which: the connecting part 14 has a gate mark 17 formed by injection molding, and has a recess 18 recessed forward between the head crown body 11 and the clip part 13; the gate mark 17 is positioned within the recess 18 so that the gate mark 17 does not protrude outward from a tangent line connecting a rear end of the head crown body 11 and a rear end of the clip part 13; an outer peripheral surface of the clip part 13 and / or the head crown body 11 has fine uneven portions; the connecting part 14 has an inclined portion 14a inclined so as to approach the head crown body 11 side as it goes rearward; and the gate mark 17 is formed in the inclined portion 14.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005] ,

[0004] , , ,

[0006]

[0001] The present invention relates to the crown of a writing instrument.

Background Art

[0002] Conventionally, synthetic resin crowns (including caps), which are components of writing instruments, are lightweight and have a texture of the resin material, and various products can be produced by injection molding using resin materials, so they are used in various writing instruments. As the synthetic resin used in injection molding, acrylic resin, ABS resin, AS resin, PP resin, PC resin, PET resin, etc. are mainly used.

[0003] When using such injection molding, there is a problem that a gate mark always remains on the molded product. On the other hand, the crown of a writing instrument (including the cap) often has a protrusion for preventing rolling and a clip part for inserting into a breast pocket or the like for carrying, so the clip part is tapered and the fluidity of the synthetic resin is poor, and the molding property of the protrusion part that requires resin thickness, the decrease in tactile sensation due to the gate mark hitting the finger when gripping, and considering the influence on appearance and aesthetics, where to provide the gate mark has become an important issue.

[0004] As a means to solve this problem, the applicant of the present application discloses in Patent Document 1 a cap of a writing instrument in which a gate is arranged near the clip part and a gate mark is formed inside the extension line of the protrusion top surface toward the cap tip side, so that the clip part has good moldability and the gate mark is difficult to hit the finger when gripping the cap with the finger.

[0005] In addition, the applicant of the present application discloses in Patent Document 2 a component of a writing instrument in which a protrusion serving as a clip is provided on the outer body of the writing instrument and a gate mark is formed on the surface of the protrusion facing the outer body, so that there are no problems such as sink marks and warping during molding without impairing the aesthetics as an appearance.

[0006] On the other hand, the crown (including the cap) of a writing instrument may not have a mirror finish on the entire outer surface of the crown and clip, but may have fine irregularities (such as a textured surface). In order to ensure that the synthetic resin flows properly into these fine irregularities during molding, the position of the gate into which the synthetic resin is injected must be determined with greater care.

[0007] However, while the gate marks in Patent Document 1 improve the moldability of the protrusions and clips because they are located near them, the gate marks are entirely facing the cap body, which slightly weakens the flow of synthetic resin to the protrusions and clips. Therefore, when fine irregularities are provided on the outer surface of the clip, there was a risk that the irregularities would not be molded cleanly. Furthermore, in Patent Document 2, the gate mark is provided on the surface facing the outer body of the protruding part that forms the clip. As a result, the flow of resin to the clip part is improved during molding, and if an uneven surface is provided on the clip part, it is formed without problems. However, the flow of resin to the crown body side is slightly weaker, so if an uneven surface is provided on the crown body side, there is a risk that the uneven surface will not be formed cleanly. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2008-55833 [Patent Document 2] Japanese Patent Publication No. 2004-351729 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention was made based on the above background, and its objective is to provide a cap for a writing instrument that has good moldability during injection molding, a cleanly formed surface with irregularities on the outer circumferential surface, and a gate mark formed in a position where it is difficult for fingers to come into contact with it. [Means for solving the problem]

[0010] This invention relates to injection-molded synthetic resin. Cap of a writing instrument and ,head The crown comprises a crown body and a clip portion connected to one end of the crown body via a connecting portion, wherein a gate mark formed by injection molding is formed on the connecting portion, and there is a recess between the crown body and the clip portion that is recessed toward the front, and the gate mark is located within the recess such that it does not protrude outward from the tangent line connecting the rear end of the crown body and the rear end of the clip portion. ,before The connecting portion has an inclined portion that slopes toward the crown body side as it moves toward the rear, and the gate mark is formed on the inclined portion. Writing instruments It is mounted so as to be able to slide back and forth relative to the shaft cylinder. ,Ko The spring biases it backward. re Characterized by Cap of a writing instrument That is the case. In this invention, the side of the crown body with the gate mark in the longitudinal direction (central axis direction) is referred to as the rear, and the opposite side is referred to as the front. Furthermore, the direction from the outer surface of the crown body toward the central axis is referred to as the inward direction, and the opposite direction is referred to as the outward direction.

[0011] According to the present invention, the gate mark is formed in a recess so that it is located inward from the tangent line connecting the rear end of the crown body and the rear end of the clip. This reduces the likelihood of fingers or other objects directly contacting the gate mark when gripping or pressing the crown, thus preventing a decrease in tactile sensation or discomfort caused by touching the gate mark. Furthermore, by providing the gate mark in the inclined portion of the connection, the synthetic resin flows firmly into the clip portion as well as the crown body during injection molding. This allows the synthetic resin to flow firmly into the uneven portions (such as textured surfaces) on the outer surface of the clip portion or the crown body, forming beautifully molded uneven portions according to the mold shape.

[0012] In addition, the gate trace may be formed perpendicular to the inclined portion, and when the inclination angle of the inclined portion with respect to the central axis of the crown body is X, it may be configured to satisfy the relational expression of 15° < X < 75°. In this case, the gate for injection molding of the mold forming the gate trace is also formed substantially perpendicular to the inclined portion. Furthermore, by setting the inclination angle of the inclined portion within a certain range, the synthetic resin can flow into the clip portion more evenly around the crown body during injection molding.

[0013] In addition, the front portion of the crown body may have a core portion that is continuously provided with the crown body and extends forward, and the side surface of the crown body or the core portion may have a plurality of slit portions that extend along the axial direction and on which the writing unit is mounted. In this case, even if the flow of the synthetic resin during injection molding is branched into a plurality by the slit portions, the synthetic resin that enters from the inclined portion can flow firmly into the core portion, so the effect of improving the fluidity of the synthetic resin becomes more prominent, which is preferable.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a crown of a writing instrument that has good moldability during injection molding, the concavo-convex portions on the outer peripheral surface are formed neatly, and a gate trace is formed at a position where it is difficult for a finger to come into contact.

Brief Description of the Drawings

[0015] [Figure 1] It is a longitudinal sectional view showing a state where the crown of the writing instrument according to the embodiment of the present invention is mounted on a slide-type multi-core writing instrument with a part omitted. [Figure 2] It is a side view of the crown of the writing instrument in the embodiment. [Figure 3] It is a sectional view showing the A-A end face of FIG. 2. [Figure 4] It is a perspective view of the crown of the writing instrument of FIG. 2.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0017] (First Embodiment) The crown 10 of the writing instrument according to the embodiment of the present invention is exemplified by a crown with a clip that can slide back and forth and is used for a slide-type multi-core writing instrument provided with a plurality of writing units 30. However, the present invention is not limited to this, and can be widely used for crowns used for writing instruments (crowns that can slide or cannot slide, caps that cover the writing part, etc.).

[0018] FIG. 1 is a longitudinal sectional view with a part omitted showing a state in which the crown of the writing instrument of the present embodiment is attached to a slide-type multi-core writing instrument, FIG. 2 is a side view of the crown of the writing instrument in the present embodiment, FIG. 3 is a sectional view showing the A-A end face of FIG. 2, and FIG. 4 is a perspective view of the crown of the writing instrument of FIG. 2.

[0019] As shown in Figure 1, the multi-core writing instrument 1 is an example of a writing instrument fitted with the cap 10 (hereinafter referred to as cap 10) of this embodiment. The side-slide type multi-core writing instrument 1 has a barrel 20 composed of a barrel body 21, a front connecting member 22 screwed onto the front inner circumference of the barrel body 21, and a rear connecting member 23 screwed onto the rear inner circumference of the barrel body 21. A tip 40 having a front end opening 41 for the writing part 31 of the writing unit 30 to extend and retract is detachably screwed onto the front of the barrel 20, and the cap 10 of this embodiment is fitted onto the rear of the barrel 20. When fitting the cap 10 onto the barrel 20, the projection 12a of the cap 10 is inserted into the groove 20a on the inner surface of the barrel, thereby allowing the cap 10 to slide back and forth relative to the barrel 20. A coil spring 60 is stretched between the cap 10 and the inner stepped portion of the barrel 20, thereby biasing the cap 10 of the writing instrument backward by the coil spring 60. One mechanical pencil unit (not shown) and two ballpoint pen units are mounted in the multiple slit portions 15 (three in this embodiment) of the cap 10 as writing units 30. A coil spring 50 is stretched between the outer stepped portion of each writing unit 30 and the front stepped portion 15a of the slit portion 15 of the cap 10, biasing the writing units 30 backward relative to the cap 10. The writing portion 31 provided at the front of each writing unit 30 is mounted in the slit portion 15 in a state where it protrudes forward from the cap 10. An operating part 32 is formed on the rear outer surface of the writing unit 30, protruding outward from the slit part 15. By sliding the operating part 32 of each writing unit 30 forward, the writing unit 30 moves forward, and the writing part 31 protrudes from the front end opening 41 of the tip 40. At this time, the locking projection 33 of the writing unit 30 and the locked projection 15b of the sliding part engage, maintaining the protruding state of the writing part 30. When retracting the protruding writing unit 30 through the front end opening 41, sliding the operating part 32 of the other writing unit forward releases the locking between the locking projection 33 and the locked projection 15b, and the writing unit 30 moves backward due to the elastic force of the coil spring, returning to the state before the extension operation. As described above, the multi-core writing instrument 1 is a conventionally known sliding type multi-core writing instrument structure.

[0020] The cap 10 of the writing instrument in this embodiment will be described in detail below, but explanations of parts that are not essential to the present invention will be omitted.

[0021] The cap 10 of the writing instrument shown in Figures 1-4 is formed by injection molding using synthetic resin and consists of a cap body 11, a core portion 12 connected to the cap body 11 and extending forward, and a clip portion 13 connected to the rear side surface of the cap body 11 via a connecting portion 14. In addition, multiple groove-shaped slit portions 15 are formed on the sides of the cap body 11 and the core portion 12. Furthermore, the outer circumferential surfaces of the clip portion 13, the cap body 11, and the core portion 12 have a textured surface 16 formed by fine irregularities. In this embodiment, a textured surface is formed as an example of the textured surface 15.

[0022] The synthetic resin constituting the crown 10 is not particularly limited as long as it is injection moldable, and can be acrylic resin, ABS resin, AS resin, PP resin, PC resin, or PET resin, etc. In this embodiment, it is formed using PC resin.

[0023] The cap body 11 is formed in a cylindrical shape with a closed rear end, and a core portion 12 extending forward is attached to the front end. The outer diameter of the core portion 12 is smaller than that of the cap body 11. The outer circumference of the core portion 12 has a projection 12a that protrudes toward the clip portion 13. Multiple slit portions 15 (three in this embodiment) are formed on the outer circumference of the cap body 11, extending axially to the front end of the core portion 12, each communicating inside the cap body 11 and the core portion 12. The front of each slit portion 15 has a narrow slit width and a front stepped portion 15a into which a coil spring 50 (described later) is locked. The slit portion 15 also has a stepped portion 15c that protrudes inward and extends axially, and the front end of the stepped portion 15c has a locking portion 15b that locks toward the locking projection 33 of the cursive writing instrument 30.

[0024] The clip portion 13 has a clip body 13a which is formed in a plate shape so as to extend along the axial direction from the crown body 11 to the outer circumference of the core portion 12, and a ball portion 13b which is formed on the side of the clip body 13a on the core portion 12 side so as to protrude toward the core portion 12.

[0025] Between the rear of the crown body 11 and the rear of the clip portion 13, a recessed area 18 is formed that curves forward. At the rear end of the connecting portion 14 that demarcates the recessed area 18, a gate is located for injecting synthetic resin into the mold during injection molding. After molding, a protruding gate mark 17 is formed when the gate is removed.

[0026] The rear end of the connecting portion 14 where the gate mark 17 is formed has an inclined portion 14a that slopes toward the central axis A of the crown body 11 as it moves backward along the axial direction, and the gate mark 17 is formed to extend perpendicularly to the inclined portion 14a. Furthermore, the tip 17a of the protruding gate mark 17 is configured to be located in front of (within the recess 18 of) the tangent line S connecting the rear end 13c of the clip portion 13 and the rear end 11a of the crown body 11, thereby preventing the user from feeling discomfort when touching the crown 10 with a finger or the like and hitting the gate mark 17. It is preferable that the distance from the tangent line S to the tip of the gate mark 17 be 1 mm or more.

[0027] Also, when the inclination angle between the central axis line A of the crown body 11 and the extension line E of the inclined portion 14a is X as shown in FIG. 3, it is preferably configured to satisfy the relational expression of 15° < X < 75°. In this case, by setting the inclination angle X of the inclined portion 14a within the range of the relational expression, when the synthetic resin flows into the connecting portion 14 from the gate during injection molding, the synthetic resin flows in from the connecting portion 14 between the crown body 11 and the clip portion 13. Therefore, the resin can easily flow into both the clip portion 13 and the crown body 11, preventing the resin flow from being deflected. Moreover, due to the inclined portion 14, the synthetic resin can be more evenly flowed into the clip portion 13 with the crown body 11 having a larger volume ratio as the center. Incidentally, it is preferable to adjust the inclination angle X of the inclined portion 14 according to the volume ratio among the clip portion 13, the crown body 11, and the core portion 12. In this embodiment, since the volumes of the crown body 11 and the core portion 12 are large, the inclination angle of the inclined portion is formed at 42° so that the flow of the resin into the crown body increases. As a result, the synthetic resin could be evenly flowed during molding. Also, by improving the fluidity of the synthetic resin during molding, the overall shape of the crown 10 of the writing instrument is firmly formed according to the mold, and the synthetic resin could also firmly flow into the concavo-convex portions 16 formed by the fine concavo-convex on the outer peripheral surfaces of the clip portion 13, the crown body 11, and the core portion 12, forming a nice embossed surface on the outer peripheral surface.

[0028] Incidentally, in the crown 10 of the present embodiment, due to the plurality of slit portions 15 formed on the side surfaces of the crown body 11 and the core portion 12, the flow of the synthetic resin is divided during injection molding, resulting in a decrease in the moldability. However, by flowing the synthetic resin from the gate trace 17 of the inclined portion 14a, the synthetic resin can firmly flow into the clip portion 13 and the ends of the core portion 12, preventing the occurrence of sink marks, distortion, etc. Therefore, when it is necessary to provide the plurality of slit portions 15 on the crown body 11 or the core portion 12 of the crown of the writing instrument of the present invention, the effect becomes remarkable.

Explanation of Reference Numerals

[0029] 1 Multi-core writing instrument 10 Crown 11 Crown body 11a Rear end portion 12 Core portion 12a Protrusion 13 Clip section 13a Clip body 13b Tamabe 13c Rear end 14 Connection part 14a Slope 15 Slit section 15a Front step 15b Stepped section 15c Locked protrusion 16 Uneven part 17 Gate ruins 17a Promontory 18 recesses 20 shaft cylinder 20a Groove 21. Shaft body 22 Front connecting member 23 Rear connecting member 30 writing units 31 Writing section 32 Operation section 33 Locking protrusion 40 Sakiguchi 41 Front end opening 50 Coil Springs 60 Coil Springs A Center axis E extension line S tangent X Tilt angle

Claims

1. The cap of a writing instrument, which is injection-molded from synthetic resin, It comprises a crown body and a clip portion connected to one end of the crown body via a connecting portion, A gate mark is formed at the connection portion by injection molding. The crown body and the clip portion have a recess that is recessed toward the front, The gate mark is a connection between the rear end of the crown body and the rear end of the clip portion. It is positioned within the recess so as not to protrude outward from the line, The connecting portion has an inclined portion that slopes toward the crown body as it moves toward the rear. And the gate mark is formed in the inclined portion. A cap for a writing instrument, characterized by being mounted so as to be slidable back and forth on the barrel of the writing instrument and biased backward by a coil spring.

2. The front part of the crown body has a core portion that is connected to the crown body and extends forward, The cap of a writing instrument according to claim 1, characterized in that the side surface of the cap body or core portion has a plurality of slit portions that extend along the axial direction and into which a writing unit is attached.

3. The cap of the writing instrument according to claim 2, characterized in that an operating portion is formed on the rear outer surface of the writing unit, protruding outward from the slit portion.

4. The cap of a writing instrument according to claim 2 or 3, characterized in that at least one of the writing units attached to the plurality of slit portions is a mechanical pencil unit.

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