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

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

Background Art

[0002] Conventionally, synthetic resin crowns (including caps), which are parts of writing instruments, are light in weight 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 for 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 gate marks always remain 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 it tapers and has poor fluidity of the synthetic resin. Considering the moldability of the clip part, the protrusion part that requires resin thickness, the decrease in tactile sensation due to the gate mark hitting the finger when gripping, and the influence on appearance and aesthetics, where to provide the gate mark is 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 from the protrusion top surface to the cap tip side, so that the moldability of the clip part is good 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 part 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 one hand, for the crown (including the cap) of the writing instrument, not all of the outer peripheries of the crown body and the clip are mirror-finished, and there may be fine uneven portions (such as a dimpled surface). In order to allow the synthetic resin to flow firmly into the fine uneven portions during molding, it is necessary to more carefully determine the installation position of the gate through which the synthetic resin is poured.

[0007] However, although the gate mark in Patent Document 1 is near the protrusion or the clip and the moldability of the protrusion or the clip is improved, since the gate mark is completely facing the cap body side, the flow of the synthetic resin flowing into the protrusion or the clip portion becomes slightly weaker. For this reason, when providing fine uneven portions on the outer peripheral surface of the clip, there was a risk that the uneven portions would not be molded neatly. And, since the gate mark in Patent Document 2 is provided on the surface facing the exterior body of the protrusion that becomes the clip portion, the flow of the resin to the clip portion during molding is improved and there is no problem when providing uneven portions on the clip portion. However, since the flow of the resin to the crown body side becomes slightly weaker, there was a risk that the uneven portions would not be formed neatly when providing uneven portions on the crown body side.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention has been made based on the above background, and an object thereof is to provide a crown of a writing instrument that has good moldability during injection molding, has fine uneven portions on the outer peripheral surface molded neatly, and has a gate mark formed at a position where it is difficult for a finger to come into contact.

Means for Solving the Problems

[0010] The present invention relates to a tiara injection-molded from a synthetic resin Writing instrument provided with and has a writing unit mounted on the head cap, a shaft cylinder on which the head cap is mounted from the rear, and a coil spring stretched between the head cap and the inner step portion of the shaft cylinder, and the head cap is a tiara body and a clip portion connected to one end of the tiara body via a connecting portion. A gate mark is formed on the connecting portion by injection molding. There is a recess recessed forward between the tiara body and the clip portion. The gate mark is located within the recess so that the gate mark does not protrude outward from the tangent line connecting the rear end of the tiara body and the rear end of the clip portion. The outer peripheral surface of the clip portion and / or the tiara body has fine uneven portions. The connecting portion has an inclined portion that inclines so as to approach the tiara body side as it goes rearward, and the gate mark is formed on the inclined portion , the head cap is slidably mounted back and forth with respect to the shaft cylinder and is biased rearward by the coil spring and is configured to be pressed forward characterized in that writing instrument it is In the present invention, the side with the gate mark in the longitudinal direction (central axis direction) of the tiara body is expressed as the rear, and the opposite side is expressed as the front. Also, the direction from the outer peripheral surface of the tiara body toward the central axis is expressed as the inner side, and the opposite direction is expressed as the outer side

[0011] According to the present invention, the gate mark is formed in the recess so that the gate mark is located inward of the tangent line connecting the rear end of the tiara body and the rear end of the clip. This can reduce the direct contact of fingers, etc. with the gate mark when the tiara is gripped or pressed, thus preventing a decrease in the tactile sensation or a sense of discomfort caused by touching the gate mark. Also, by providing the gate mark on the inclined portion provided on the connecting portion, the synthetic resin flows firmly into the clip portion around the tiara body side during injection molding. Therefore, the synthetic resin flows firmly into the uneven portions (such as the embossed surface) provided on the outer peripheral surface of the clip portion or the tiara body, and the uneven portions are formed beautifully in the shape of the mold in can be formed

[0012] Further, 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. Further, 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] Also, in the front part of the crown body body there is a core part that is continuously provided on the crown body and extends forward. On the side surface of the crown body or the core part, a plurality of slit parts along the axial direction the wherein a writing unit is mounted may be provided. In this case, even if the flow of the synthetic resin during injection molding is branched into a plurality by the slit parts, the synthetic resin that enters from the inclined portion can flow firmly into the core part. Therefore, the effect of improving the fluidity of the synthetic resin becomes more remarkable, which is preferable. having

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 uneven portions on the outer peripheral surface are molded 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]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Modes 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 as a crown with a clip that can slide back and forth and is used for a slide-type multi-core writing instrument having a plurality of writing units 30. However, the present invention is not limited to this and can be widely used for crowns used in writing instruments (crowns that can or cannot slide, caps that cover the writing part, etc.).

[0018] FIG. 1 is a longitudinal sectional view, partially 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. FIG. 4 is a perspective view of the crown of the writing instrument of FIG. 2.

[0019] As shown in Fig. 1, the multi-core writing instrument 1 is an example of a writing instrument with the crown 10 (hereinafter referred to as the crown 10) of the writing instrument of the present embodiment attached thereto. The side-slide type multi-core writing instrument 1 is composed of a shaft cylinder 20, which is constituted by a shaft cylinder main body 21, a front connecting member 22 screwed to the inner peripheral portion of the front part of the shaft cylinder main body 21, and a rear connecting member 23 screwed to the inner peripheral portion of the rear part of the shaft cylinder main body 21. Further, a tip 40 having a front end opening 41 for the writing part 31 of the writing unit 30 to protrude and retract is detachably screwed to the front part of the shaft cylinder 20, and the crown 10 of the writing instrument of the present embodiment is attached to the rear part of the shaft cylinder 20. When attaching the crown 10 to the shaft cylinder 20, the protrusion 12a of the crown 10 is inserted into the groove 20a on the inner surface of the shaft cylinder, so that the crown 10 is slidably attached to the shaft cylinder 20 in the front-rear direction. A coil spring 60 is stretched between the crown 10 and the inner stepped portion of the shaft cylinder 20, whereby the crown 10 of the writing instrument is biased rearward by the coil spring 60. One mechanical pencil unit (not shown) and two ballpoint pen units are attached to the plurality of slit portions 15 (three places in the present embodiment) of the crown 10 as the writing unit 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 crown 10, and the writing unit 30 is biased rearward with respect to the crown 10. The writing part 31 provided at the front part of each writing unit 30 is attached to the slit portion 15 in a state of protruding forward from the crown 10. An operation part 32 protruding outward from the slit portion 15 is formed on the outer surface of the rear part of the writing unit 30. By sliding the operation 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 protrusion 33 of the writing unit 30 and the locked protrusion 15b of the slide part are locked, so that the protruding state of the writing part 30 is maintained. When immersing the protruding writing unit 30 from the front end opening 41, by sliding the operation part 32 of the other writing unit forward, the locking state between the locking protrusion 33 and the locked protrusion 15b is released, and the writing unit 30 moves rearward by the elastic force of the coil spring and can return to the state before the feeding operation. As described above, the multi-core writing instrument 1 has a conventionally known slide type multi-core writing instrument structure.

[0020] The crown 10 of the writing instrument according to the present embodiment will be described in detail below, but the description will be omitted for parts that are not the gist of the present invention.

[0021] The crown 10 of the writing instrument shown in FIGS. 1 to 4 is formed by injection molding using a synthetic resin, and includes a crown body 11, a core part 12 that is connected to the crown body 11 and extends forward, and a clip part 13 that is connected to the rear side surface of the crown body 11 via a connecting part 14. Further, a plurality of slit parts 15 formed in a groove shape are formed on the side surfaces of the crown body 11 and the core part 12. And, the outer peripheral surfaces of the clip part 13, the crown body 11, and the core part 12 have uneven parts 16 formed by fine unevenness. In the present embodiment, a dimpled surface is formed as an example of the uneven part 15.

[0022] The synthetic resin constituting the crown 10 can be used without particular limitation as long as it can be injection molded, and acrylic resin, ABS resin, AS resin, PP resin, PC resin, PET resin, etc. can be used. In the present embodiment, it is formed using PC resin.

[0023] The crown body 11 is formed in a cylindrical shape with the rear part closed, and a core part 12 extending forward is continuously provided at the front end part. The outer diameter of the core part 12 is formed smaller than that of the crown body 11. The outer peripheral part of the core part 12 has a protruding part 12a that protrudes toward the clip part 13. A plurality of slit parts 15 (three places in the present embodiment) that extend along the axial direction to the front end of the core part 12 and communicate with each other inside the crown body 11 and the core part 12 are formed on the outer peripheral part of the crown body 11. At the front part of the slit part 15, the slit width is narrow, and a front step part 15a where a coil spring 50 described later is locked is formed. Further, a step part 15c that protrudes inward and extends along the axial direction is formed in the slit part 15, and a locked part 15b that is locked to the locking protrusion 33 of the writing body 30 is formed at the front end part of the step part 15c.

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

[0025] A recess 18 that is recessed forward is formed between the rear portion of the crown body 11 and the rear portion of the clip portion 13. At the rear end of the connecting portion 14 that defines the recess 18, a gate for pouring synthetic resin into the mold during injection molding is located, and a protruding gate mark 17 is formed when the gate is separated after molding.

[0026] The rear end of the connecting portion 14 where the gate mark 17 is formed has an inclined portion 14a that inclines so as to approach the central axis A side of the crown body 11 as it advances rearward along the axial direction, and the gate mark 17 is formed so as to extend perpendicular to the inclined portion 14a. Further, by configuring the protruding end 17a of the protruding gate mark 17 to be located in front (inside the recess 18) of the tangent line S that connects the rear end portion 13c of the clip portion 13 and the rear end portion 11a of the crown body 11, it is possible to prevent 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 protruding end of the gate mark 17 is configured to be 1 mm or more.

[0027] Further, 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 connection portion 14 from the gate during injection molding, the synthetic resin flows in from the connection 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 poured into the clip portion 13 with the crown body 11 having a larger volume ratio as the center. Incidentally, the inclination angle X of the inclined portion 14 is preferably adjusted 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 poured in evenly 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 flow firmly into the uneven portions 16 formed by the fine unevenness on the outer peripheral surfaces of the clip portion 13, the crown body 11, and the core portion 12, enabling the formation of a nice uneven surface on the outer peripheral surface.

[0028] Incidentally, in the crown 10 of this embodiment, the flow of the synthetic resin is divided by the plurality of slit portions 15 formed on the side surfaces of the crown body 11 and the core portion 12 during injection molding, resulting in a decrease in moldability. However, by pouring the synthetic resin from the gate trace 17 of the inclined portion 14a, the synthetic resin can flow firmly to the ends of the clip portion 13 and 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 in the crown body 11 or the core portion 12 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 projection 13 clip portion 13a clip body 13b ball portion 13c rear end portion 14 connecting portion 14a inclined portion 15 slit portion 15a front step portion 15b step portion 15c engaged projection 16 concavo-convex portion 17 gate trace 17a protruding end 18 concave portion 20 shaft cylinder 20a groove portion 21 shaft cylinder body 22 front connecting member 23 rear connecting member 30 writing unit 31 writing portion 32 operation portion 33 locking projection 40 tip opening 41 front end opening 50 coil spring 60 coil spring A central axis E extension line S tangent line X inclination angle

Claims

1. A writing instrument having a crown injection-molded from a synthetic resin, comprising: a writing unit attached to the crown, a shaft cylinder to which the crown is attached from the rear, and a coil spring stretched between the crown and the inner step of the shaft cylinder; the crown has a crown body and a clip portion continuously provided at one end of the crown body via a connecting portion; a gate mark is formed in the connecting portion by injection molding; a recess recessed forward is provided between the crown body and the clip portion; the gate mark is located within the recess so as not to protrude outward from a tangent line connecting the rear end of the crown body and the rear end of the clip portion; the outer peripheral surface of the clip portion and / or the crown body has fine irregularities; the connecting portion has an inclined portion that inclines so as to approach the crown body side as it goes rearward, and the gate mark is formed in the inclined portion; the crown is slidably attached to the shaft cylinder in the front-rear direction and is biased rearward by the coil spring and is configured to be pressable forward. A writing instrument characterized by this.

2. The front portion of the crown body has a core portion continuously provided to the crown body and extending forward; The writing instrument according to claim 1, further comprising a plurality of slit portions formed on a side surface of the crown body or the core portion and extending along the axial direction, to which the writing unit is attached.

3. The writing instrument according to claim 2, wherein an operation portion protruding outward from the slit portion is formed on an outer surface of a rear portion of the writing unit.

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