JP2023040867A - Head crown of writing utensil - Google Patents

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

The present invention relates to a crown for writing instruments.

Traditionally, head crowns (including caps) made of synthetic resin, which are parts of writing instruments, are light in weight and have the feel of a resin material, making it possible to manufacture various products by injection molding. Therefore, it is used in various writing instruments. Acrylic resin, ABS resin, AS resin, PP resin, PC resin, PET resin, or the like is mainly used as a synthetic resin used for injection molding.

When using such injection molding, there is always a problem that gate marks remain on the molded product. Since it often has a clip part for carrying, the clip part is tapered and the fluidity of the synthetic resin is poor, the moldability of the protrusion part that requires a thick resin, and the gate mark hits the finger when gripping Considering the deterioration of the tactile sensation and the influence on the appearance and aesthetics, it is an important issue to determine where to place the gate mark.

As a means of solving this problem, the applicant of the present application has disclosed in Patent Document 1 that a gate is arranged near the clip portion and a trace of the gate is formed inside the extension line of the top surface of the projection toward the tip of the cap. Thus, the cap of a writing utensil has good moldability to the clip portion, and when the cap is gripped with the fingers, the gate traces are less likely to come into contact with the fingers.

In addition, the applicant of the present application discloses in Patent Document 2 that a projection that serves as a clip is provided on the exterior main body of a writing instrument, and a gate mark is formed on the surface of the projection that faces the exterior main body, thereby impairing the aesthetic appearance of the writing instrument. The present invention discloses a part of a writing instrument that does not have problems such as sink marks and distortion during molding.

On the other hand, the crown of a writing instrument (including the cap) does not have a mirror finish on the entire circumference of the crown body and the clip, and fine irregularities (textured surface, etc.) may be formed, and fine irregularities may occur during molding. In order to ensure that the synthetic resin flows into the part, it is necessary to carefully determine the installation position of the gate into which the synthetic resin is poured.

However, although the gate marks in Patent Document 1 are in the vicinity of the protrusions and clips, the moldability of the protrusions and clips is improved, but since the gate marks are completely facing the cap body side, the protrusions and the clips The flow of the synthetic resin flowing into the part becomes slightly weaker. For this reason, when minute irregularities are provided on the outer peripheral surface of the clip, there is a risk that the irregularities may not be formed neatly.
In addition, since the gate mark in Patent Document 2 is provided on the surface of the projecting portion that serves as the clip portion facing the exterior main body, the flow of the resin to the clip portion is improved during molding, and the uneven portion is provided on the clip portion. However, the flow of the resin to the crown main body side is slightly weakened, and when the concave and convex portions are provided on the crown main body side, there is a risk that the concave and convex portions will not be formed neatly.

JP-A-2008-55833 JP-A-2004-351729

The present invention has been made based on the above background, and its object is to provide good moldability at the time of injection molding, so that the irregularities on the outer peripheral surface are formed neatly, and a position where fingers are unlikely to come into contact. To provide a crown of a writing instrument having gate traces formed in the space.

The present invention provides a head crown for a writing instrument injection-molded from a synthetic resin, comprising: a head crown body; A gate trace is formed in the portion by injection molding, and has a concave portion recessed forward between the crown body and the clip portion. Located in the recess so as not to protrude outward from a tangent line connecting the rear end of the clip portion, the clip portion and/or the outer peripheral surface of the crown body has fine uneven portions, and the connecting portion The head crown of a writing instrument is characterized in that it has an inclined portion that inclines so as to approach the crown main body as it goes rearward, and that the gate mark is formed on the inclined portion.
In the present invention, the side on which the gate marks are present in the longitudinal direction (center axis direction) of the crown body is referred to as the rear, and the opposite side is referred to as the front. Also, the direction from the outer peripheral surface of the crown main body to the central axis is expressed as inward, and the opposite direction is expressed as outward.

According to the present invention, the gate mark is formed in the recess so that the gate mark is positioned inward of a tangent line connecting the rear end of the crown body and the rear end of the clip. Since it is possible to reduce the direct contact of the finger or the like with the gate mark when the crown is gripped or pressed, it is possible to prevent a decrease in tactile sensation and a sense of discomfort caused by touching the gate mark. In addition, by providing the gate mark on the slanted part of the connection part, the synthetic resin will flow into the clip part, centering on the crown body side, during injection molding. Synthetic resin flows firmly into uneven parts (textured surface, etc.), and it is possible to form uneven parts that are neatly molded according to the shape of the mold.

Further, when the gate mark is formed perpendicular to the inclined portion and the inclination angle of the inclined portion with respect to the central axis of the crown body is X, the relational expression of 15°<X<75° is satisfied. In this case, the gate for injection molding of the mold that forms the gate trace is also formed substantially perpendicular to the inclined portion, and the inclination angle of the inclined portion is within a certain range. As a result, the synthetic resin can be made to flow into the clip portion in a more balanced manner centering on the crown body side at the time of injection molding.

In addition, the front portion of the crown piece has a core portion that is connected to the crown body and extends forward, and the side surface of the crown body or the core portion extends along the axial direction. It may have a plurality of slits to which the unit is attached. In this case, even if the flow of the synthetic resin at the time of injection molding is divided into a plurality by the slits, the synthetic resin entering from the inclined part will not flow into the core. Since it flows firmly to the part, the effect of improving the fluidity of the synthetic resin becomes more remarkable, which is suitable.

According to the present invention, it is possible to provide a crown for a writing instrument which has good moldability during injection molding, has fine irregularities formed on the outer peripheral surface, and has gate traces formed at positions where fingers are unlikely to come into contact.

FIG. 2 is a partially omitted vertical cross-sectional view showing a state in which the crown of the writing instrument according to the embodiment of the present invention is attached to a sliding multi-core writing instrument. It is a side view of the crown of the writing instrument in the embodiment. FIG. 3 is a sectional view showing the AA end face of FIG. 2; Figure 3 is a perspective view of the crown of the writing instrument of Figure 2;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
The head crown 10 of the writing instrument according to the embodiment of the present invention is an example of a head crown with a clip that can slide back and forth for use in a slide-type multi-core writing instrument having a plurality of writing units 30. is not limited to this, and can be widely used for crowns used in writing instruments (slidable or non-slidable crowns, caps covering writing parts, etc.).

FIG. 1 is a partially omitted vertical cross-sectional view showing a state in which the crown of the writing instrument of the present embodiment is attached to a sliding multi-core writing instrument, and FIG. 2 is a side view of the crown of the writing instrument of the present embodiment. 3 is a 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.

As shown in FIG. 1, a multi-core writing instrument 1 is an example of a writing instrument equipped with a crown 10 (hereinafter referred to as a crown 10) of the writing instrument of the present embodiment. A side-slide type multi-core writing instrument 1 has a barrel 20 which consists of a barrel main body 21, a front connecting member 22 screwed to the front inner circumference of the barrel main body 21, and a rear inner circumference of the barrel main body 21. and a rear connecting member 23 screwed to the part. A tip 40 having a front end opening 41 for retracting and protruding the writing unit 31 of the writing unit 30 is detachably screwed to the front part of the barrel 20. A crown 10 of a writing instrument in the form is attached. When the crown 10 is attached to the barrel 20, the crown 10 is slidably attached to the barrel 20 back and forth by inserting the projections 12a of the crown 10 into the grooves 20a on the inner surface of the barrel 20. be. A coil spring 60 is stretched between the crown 10 and the inner stepped portion of the barrel 20, whereby the crown 10 of the writing instrument is biased backward by the coil spring 60. As shown in FIG. One mechanical pencil unit (not shown) and two ballpoint pen units are attached as writing units 30 to the plurality of slits 15 (three in this embodiment) of the crown 10 . A coil spring 50 is stretched between the outer step portion of each writing unit 30 and the front step portion 15a of the slit portion 15 of the crown 10, and the writing unit 30 is biased backward with respect to the crown 10. A writing section 31 provided at the front of each writing unit 30 is attached to the slit section 15 in a state of protruding forward from the crown 10 . An operation portion 32 projecting outward from the slit portion 15 is formed on the rear outer surface of the writing unit 30. By sliding the operation portion 32 of each writing unit 30 forward, the writing unit 30 advances. A writing part 31 protrudes from a front end opening 41 of the tip 40 . At this time, the projection state of the writing unit 30 is maintained by the engagement between the locking projection 33 of the writing unit 30 and the locked projection 15b of the sliding portion. When the protruding writing unit 30 is retracted from the front end opening 41, the operation portion 32 of the other writing unit is slid forward to release the locked state between the locking projection 33 and the locked projection 15b. The writing unit 30 can be moved backward by the elastic force of the coil spring and returned to the state before the drawing operation. As described above, the multi-core writing instrument 1 has a conventionally known slide-type multi-core writing instrument structure.

The head crown 10 of the writing instrument of the present embodiment will be described in detail below, but descriptions of parts that are not the gist of the present invention will be omitted.

The crown 10 of the writing instrument shown in FIGS. 1 to 4 is formed by injection molding using a synthetic resin. and a clip portion 13 connected to the rear side surface of the main body 11 via a connecting portion 14 . A plurality of groove-shaped slits 15 are formed on the side surfaces of the head crown main body 11 and core part 12 . The outer peripheral surfaces of the clip portion 13, the crown main body 11 and the core portion 12 are provided with uneven portions 16 formed of fine unevenness. In this embodiment, a textured surface is formed as an example of the uneven portion 15 .

The synthetic resin forming the crown 10 is not particularly limited as long as it can be injection molded, and acrylic resin, ABS resin, AS resin, PP resin, PC resin, PET resin, or the like can be used. In this embodiment, it is formed using PC resin.

The head crown main body 11 is formed in a cylindrical shape with a closed rear portion, and a core portion 12 extending forward is connected to the front end portion. The outer diameter of the core part 12 is formed to be smaller than that of the crown main body 11 . The core portion 12 has a projection portion 12 a projecting toward the clip portion 13 on the outer peripheral portion thereof. A plurality of slits 15 (three slits in the present embodiment) extend along the axial direction to the front end of the core portion 12 and communicate with each other inside the crown body 11 and the core portion 12 . In the front part of the slit part 15, there is formed a front step part 15a having a narrow slit width and engaging a coil spring 50, which will be described later. The slit portion 15 is formed with a stepped portion 15c that protrudes inward and extends along the axial direction. 15b is formed.

The clip portion 13 has a plate-like clip body 13a extending axially from the crown main body 11 to the outer peripheral portion of the core portion 12, and a side surface of the clip body 13a on the core portion 12 side. , and a ball portion 13 b formed to protrude toward the core portion 12 .

Between the rear portion of the head crown body 11 and the rear portion of the clip portion 13, a recess 18 is formed that is recessed forward, and the rear end of the connection portion 14 that defines the recess 18 is made of synthetic resin and metal at the time of injection molding. A gate for pouring into the mold is positioned, and a protruding gate mark 17 is formed when the gate is cut off after molding.

The rear end of the connecting portion 14 where the gate mark 17 is formed has an inclined portion 14a that is inclined toward the central axis A side of the crown body 11 as it progresses rearward along the axial direction. The mark 17 is formed so as to extend perpendicularly to the inclined portion 14a. Further, the protruding end 17a of the protruding gate mark 17 is configured to be positioned forward (inside 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. As a result, it is possible to prevent the user from feeling a sense of incongruity due to contact with the gate mark 17 when the crown 10 is touched with a finger or the like. In addition, it is preferable that the tangent line S is separated from the tip of the gate mark 17 by 1 mm or more.

Further, as shown in FIG. 3, when the inclination angle between the extension line E of the inclined portion 14a and the center axis A of the crown body 11 is X, the relational expression 15°<X<75° should be satisfied. 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 from the gate into the connecting portion 14 during injection molding, the intermediate portion between the crown body 11 and the clip portion 13 Since the synthetic resin flows from the connecting portion 14, the resin easily flows into both the clip portion 13 and the crown main body 11, preventing uneven flow of the resin. The synthetic resin can be made to flow into the clip portion 13 in a more balanced manner centering on the 11 side. The inclination angle X of the inclined portion 14 is preferably adjusted according to the volume ratio of the clip portion 13 to the crown main body 11 and core portion 12 . In this embodiment, since the volume of the crown main body 11 and the core part 12 is large, the inclination angle of the inclined part is formed at 42° so that the flow of the resin to the crown main body is increased. This made it possible to flow the synthetic resin in a well-balanced manner during molding. In addition, 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 clip portion 13, the crown main body 11, and the core portion 12 are formed. The synthetic resin was able to flow firmly into the irregularities 16 formed by fine irregularities on the outer peripheral surface, and a fine textured surface could be formed on the outer peripheral surface.

In the head crown 10 of the present embodiment, the plurality of slits 15 formed on the side surfaces of the head crown body 11 and the core part 12 cut off the flow of the synthetic resin during injection molding, resulting in a decrease in moldability. By pouring the synthetic resin from the gate mark 17 of the inclined portion 14a, the synthetic resin flows firmly to the end portions of the clip portion 13 and the core portion 12, thereby preventing sink marks, distortion, and the like. For this reason, the crown of the writing instrument of the present invention has a remarkable effect when it is necessary to provide a plurality of slit portions 15 in the crown main body 11 or core portion 12 .

1 multicore writing instrument 10 crown 11 crown body 11a rear end 12 core 12a projection 13 clip 13a clip body
13b ball portion 13c rear end portion 14 connecting portion 14a inclined portion 15 slit portion 15a front stepped portion 15b stepped portion 15c engaged projection 16 uneven portion 17 gate mark 17a tip 18 recessed portion 20 shaft tube 20a groove portion 21 shaft tube main body 22 front portion Connecting member 23 Rear connecting member 30 Writing unit 31 Writing part 32 Operating part 33 Locking protrusion 40 Tip 41 Front end opening 50 Coil spring 60 Coil spring A Center axis E Extension line S Tangent line X Angle of inclination

Claims (3)

A crown of a writing instrument injection molded from a synthetic resin,
having a head crown main body and a clip section connected to one end of the head crown main body via a connecting section;
A gate mark is formed by injection molding on the connecting portion,
having a recess recessed forward between the head crown body and the clip portion;
The gate mark is positioned within the recess so that the gate mark does not 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 uneven portions,
The headpiece of a writing instrument, wherein the connection part has an inclined part that is inclined toward the crown body as it goes rearward, and the gate mark is formed on the inclined part. The gate mark is formed perpendicular to the slant portion, and satisfies a relational expression of 15°<X<75°, where X is the slant angle of the slant portion with respect to the central axis of the crown body. The crown of the writing instrument according to claim 1, characterized by: The front part of the head crown has a core part connected to the head crown body and extending forward,
3. The crown of a writing instrument according to claim 1, wherein a side surface of said crown main body or core portion has a plurality of slits extending along the axial direction and into which a writing unit is mounted.

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