Head crown of writing utensil

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 a writing instrument crown. [Background technology]

[0002] Synthetic resin crowns (including caps), which are components of writing instruments, have traditionally been used in a variety of writing instruments due to their light weight, the texture of resin, and the ability to be produced into a variety of products by injection molding depending on the resin material. The synthetic resins used in injection molding are mainly acrylic resin, ABS resin, AS resin, PP resin, PC resin, or PET resin.

[0003] When using this type of injection molding, there is the problem that gate marks are always left on the molded product. On the other hand, since the crowns (including caps) of writing instruments often have protrusions to prevent rolling and clips for inserting into a breast pocket or the like when carrying them, the location of the gate marks is an important issue, taking into consideration the moldability of the tapered clip, which has poor fluidity in synthetic resin, the protrusions that require thickness of resin, the reduced tactile feel caused by the gate marks touching the fingers when holding the product, and the impact on appearance and aesthetics.

[0004] As a means of solving this problem, the applicant of the present application discloses in Patent Document 1 a writing instrument cap in which a gate is positioned near the clip portion and a gate mark is formed inside the extension line of the top surface of the protrusion toward the tip of the cap, thereby making it easy to mold to the clip portion and making it difficult for the gate mark to come into contact with fingers when the cap is held with fingers.

[0005] Furthermore, in Patent Document 2, the applicant discloses a writing instrument part that does not suffer from problems such as sink marks or distortion during molding, without impairing the aesthetic appearance, by providing a protrusion that acts as a clip on the exterior body of the writing instrument and forming a gate mark on the surface of the protrusion facing the exterior body.

[0006] On the other hand, the crowns (including caps) of writing instruments do not have a mirror finish on the entire outer periphery of the crown body or clip, and in some cases, fine irregularities (such as a textured surface) are formed.In order to ensure that the synthetic resin flows properly into the fine irregularities during molding, the location of the gate through which the synthetic resin is poured must be determined more carefully.

[0007] However, although the gate marks in Patent Document 1 are located near the protrusions and clips, improving the moldability of the protrusions and clips, the gate marks are completely oriented toward the cap body, which slightly weakens the flow of synthetic resin toward the protrusions and clips. As a result, if fine irregularities are provided on the outer peripheral surface of the clip, there is a risk that the irregularities will not be molded cleanly. Furthermore, the gate marks in Patent Document 2 are provided on the surface of the protrusion that becomes the clip portion, facing the exterior body. This allows the resin to flow well to the clip portion during molding, and if an uneven portion is provided on the clip portion, it can be formed without any problems. However, the flow of resin toward the crown body side is somewhat weaker, so if an uneven portion is provided on the crown body side, the uneven portion may not be formed cleanly. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-55833 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-351729 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in light of the above background, and its object is to provide a writing instrument crown that has good moldability during injection molding, has a cleanly molded uneven portion on the outer peripheral surface, and has gate marks formed in a position that is difficult for fingers to come into contact with. [Means for solving the problem]

[0010] The present invention is an injection molded plastic Writing instrument crown And ,head The crown has a crown body and a clip part connected to one end of the crown body via a connecting part, and a gate mark formed by injection molding is formed in the connecting part, and a recess recessed forward is formed between the crown body and the clip part, and 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 part. ,before The connecting portion has an inclined portion that inclines toward the crown body side as it goes rearward, and the gate mark is formed on the inclined portion, Writing implements It is mounted so that it can slide back and forth relative to the shaft cylinder. ,Ko The wheel spring biases it backward. was Characterized by Writing instrument crown is. In the present invention, the side of the crown body in the longitudinal direction (central axis direction) where the gate mark is located is referred to as the rear, and the opposite side is referred to as the front. Furthermore, the direction from the outer circumferential 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 the gate mark is located inward from the tangent line connecting the rear end of the crown body and the rear end of the clip, thereby reducing direct contact of fingers with the gate mark when the crown is gripped or pressed, thereby preventing a decrease in tactile sensation or discomfort caused by touching the gate mark. Furthermore, by providing the gate mark on an inclined portion of the connection portion, the synthetic resin during injection molding flows firmly into the clip portion, mainly toward the crown body, and therefore flows firmly into the uneven portion (such as a grained surface) provided on the outer peripheral surface of the clip portion or crown body, allowing the formation of an uneven portion that is neatly molded according to the shape of the mold.

[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] Further, the front portion of the crown body may have a core portion that is continuously provided on 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 remarkable, 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 in the embodiment of the present invention is exemplified as a crown with a clip that can slide back and forth and is used in a sliding multi-core writing instrument with multiple writing units 30, but the present invention is not limited to this and can be widely used for crowns used in writing instruments (slidable or non-slidable crowns, caps that cover the writing part, etc.).

[0018] FIG. 1 is a longitudinal cross-sectional view with some parts omitted showing the state in which the crown of the writing instrument of this embodiment is attached to a sliding multi-core writing instrument, FIG. 2 is a side view of the crown of the writing instrument of this embodiment, FIG. 3 is a cross-sectional view showing the AA 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 FIG. 1, a multi-core writing instrument 1 is an example of a writing instrument equipped with a crown 10 of the writing instrument of this embodiment (hereinafter referred to as crown 10). The side-slide type multi-core writing instrument 1 has a barrel 20 composed of a barrel main body 21, a front connecting member 22 screwed onto the front inner periphery of the barrel main body 21, and a rear connecting member 23 screwed onto the rear inner periphery of the barrel main body 21. A tip 40 having a front-end opening 41 through which the writing part 31 of the writing unit 30 protrudes and retracts is removably screwed onto the front of the barrel 20, and the crown 10 of the writing instrument of this embodiment is attached to the rear of the barrel 20. When attaching the crown 10 to the barrel 20, the protrusion 12a of the crown 10 is inserted into the groove 20a on the inner surface of the barrel, so that the crown 10 is attached to the barrel 20 so as to be slidable back and forth. A coil spring 60 is stretched between crown 10 and the inner step of barrel 20, whereby crown 10 of the writing instrument is biased rearward by coil spring 60. One mechanical pencil unit (not shown) and two ballpoint pen units are attached to a plurality of slit portions 15 (three in this embodiment) in crown 10 as writing units 30. A coil spring 50 is stretched between the outer step of each writing unit 30 and front step 15a of slit portion 15 in crown 10, biasing writing unit 30 rearward relative to crown 10, and writing portion 31 provided at the front of each writing unit 30 is attached to slit portion 15 in a state where it protrudes forward from crown 10. The rear outer surface of each writing unit 30 is formed with an operating portion 32 that protrudes outward from the slit portion 15. By sliding the operating portion 32 of each writing unit 30 forward, the writing unit 30 advances, and the writing portion 31 protrudes from the front-end opening 41 of the tip opening 40. At this time, the locking protrusion 33 of the writing unit 30 engages with the locking protrusion 15b of the slide portion, maintaining the protruding state of the writing portion 30. To retract the protruding writing unit 30 from the front-end opening 41, the operating portion 32 of the other writing unit is slid forward, releasing the locking protrusion 33 from the locking protrusion 15b. The writing unit 30 then moves rearward due to the resilience of the coil spring, returning it to the state it was in before the extension operation. As described above, the multi-core writing instrument 1 has a conventionally known sliding-type multi-core writing instrument structure.

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

[0021] Crown 10 of the writing instrument shown in Figures 1 to 4 is formed by injection molding using synthetic resin, and is composed of crown body 11, core portion 12 connected to crown body 11 and extending forward, and clip portion 13 connected to the rear side of crown body 11 via connecting portion 14. A plurality of groove-like slit portions 15 are formed in the side surfaces of crown body 11 and core portion 12. The outer peripheral surfaces of clip portion 13, crown body 11, and core portion 12 have uneven portion 16 formed with fine irregularities. In this embodiment, a grained surface is formed as an example of uneven portion 15.

[0022] The synthetic resin that makes up crown 10 is not particularly limited as long as it is injection moldable, and examples that can be used include acrylic resin, ABS resin, AS resin, PP resin, PC resin, and PET resin. In this embodiment, crown 10 is formed using PC resin.

[0023] Crown body 11 is cylindrical with a closed rear, and is connected to its front end by a core portion 12 that extends forward. Core portion 12 has a smaller outer diameter than crown body 11. Core portion 12 has a protrusion 12a on its outer periphery that protrudes toward clip portion 13. Crown body 11 has a plurality of slits 15 (three in this embodiment) formed on its outer periphery, each extending axially to the front end of core portion 12 and communicating with the interiors of crown body 11 and core portion 12. The front of each slit 15 has a narrow front step 15a that engages with a coil spring 50 (described later). Slit 15 also has a step 15c that protrudes inward and extends axially, and a locking portion 15b that locks onto a locking projection 33 of writing element 30 at its front end.

[0024] The clip portion 13 has a clip body 13a formed in a plate shape extending axially from the crown body 11 to the outer periphery of the core portion 12, and a ball portion 13b formed on the side of the clip body 13a facing the core portion 12 so as to protrude toward the core portion 12.

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

[0026] The rear end of connecting portion 14, where gate mark 17 is formed, has an inclined portion 14a that slopes toward central axis A of crown body 11 as it progresses rearward along the axial direction, and gate mark 17 is formed to extend perpendicular to inclined portion 14a. Furthermore, by configuring tip 17a of protruding gate mark 17 to be located forward (inside recess 18) of tangent line S connecting rear end 13c of clip portion 13 and rear end 11a of crown body 11, it is possible to prevent the user from feeling uncomfortable when touching crown 10 with a finger or the like and coming into contact with gate mark 17. It is preferable to configure the tip of gate mark 17 so that it is 1 mm or more away from tangent line S.

[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 biased. Moreover, due to the inclined portion 14, the synthetic resin can be made to flow into the clip portion 13 more evenly around the crown body 11 with a larger volume ratio. 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 as to increase the resin flow into the crown body. As a result, the synthetic resin could be made to flow 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 can also flow firmly 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, enabling a beautiful textured surface to be formed 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 flowing 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, warping, 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 part 13a Clip body 13b Tamabe 13c Rear end 14 Connection 14a Slope 15 Slit section 15a Front step 15b Stepped section 15c Locked protrusion 16 Uneven part 17 Gate Remains 17a Tip 18 Recess 20 shaft cylinder 20a Groove 21. Body of barrel 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 spring 60 coil spring A Center axis E extension line S tangent X Tilt angle

Claims

1. A writing instrument crown injection-molded from synthetic resin, A crown body and a clip part connected to one end of the crown body via a connecting part, A gate mark is formed on the connection portion by injection molding, A recess recessed forward is provided between the crown body and the clip portion, The gate mark is a joint that connects the rear end of the crown body and the rear end of the clip portion. located within the recess so as not to protrude outward from the line; The connecting portion has an inclined portion that inclines toward the crown body side as it goes rearward. The gate trace is formed on the inclined portion, A writing instrument crown that is slidably attached to the barrel of the writing instrument and is biased rearward by a coil spring.

2. The front portion of the crown body has a core portion connected to the crown body and extending forward, 2. The writing implement crown according to claim 1, wherein the crown body or the tang portion has a side surface on which a plurality of slits extending along the axial direction are attached, and into which writing units are attached.

3. 3. The writing implement crown according to claim 2, wherein an operating portion is formed on the rear outer surface of said writing unit, said operating portion protruding outward from said slit portion.

4. A writing instrument crown as described in claim 2 or 3, characterized in that at least one of the writing units attached to the multiple slit portions is a mechanical pencil unit.

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