JP3487020B2 - Writing instrument cap - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a ridge on the bottom portion of a writing instrument main body which is positioned against each other by being abutted against the writing instrument main body when the writing instrument main body is mounted. The present invention relates to a cap for a writing instrument made of a synthetic resin having an air circulation hole for preventing suffocation at the top. 2. Description of the Related Art Conventionally, in order to determine a mounting position of a cap of a writing implement and a writing implement main body, a ridge is formed on a bottom portion, and the ridge is abutted on an appropriate position of the writing implement main body. Are known. As an example, Japanese Utility Model Application Laid-Open No. 56-146584
Japanese Unexamined Patent Publication (Kokai) No. H10-26095. [0003] Further, there is known a writing instrument in which an air circulation hole is secured so as not to suffocate even if a child or the like accidentally swallows the cap. As an example,
As disclosed in Japanese Utility Model Laid-Open No. 5-88988, an air circulation hole is formed at the center of the top,
As disclosed in JP-A-58363, there is an apparatus in which the center of the top is an island-shaped portion, and air circulation holes are formed at radial positions on the top centered on the island-shaped portion. [0004] However, when the above-described airflow hole for preventing suffocation is formed in the above-described writing instrument cap having a projection formed on the bottom portion, it is difficult to form a composite. As a resin injection-molded product, a problem occurs in durability of a molding die. [0005] That is, in the molding die, the portion forming the air flow hole of the cap is a portion for bringing the cavity (outer die) into contact with the core pin (inner die), and the portion forming the ridge is the core pin. In which a concave portion is formed. Here, if a large ridge is formed, a so-called sink mark in which a concave portion is formed in the molded product due to the shrinkage of the synthetic resin, so that the ridge is preferably formed as thin as possible. A narrow groove is formed in the core pin forming the ridge. When the molding is performed, a strong force is applied to a portion of the molding die where the air flow hole is formed. However, if a groove portion of the core pin for forming the above-mentioned ridge exists near the portion, the portion of the portion is formed. There was a problem that the durability was remarkably inferior. In particular, this has led to breakage of a molding die, such as when molding is performed continuously. That is, according to the present invention, when the writing tool body is mounted on the bottom, a ridge is formed which is abutted against the writing tool body so as to position each other, and the top is suffocated. In a cap of a writing instrument made of synthetic resin provided with an air flow hole for prevention, the air flow hole is formed in one area divided by a straight line passing through the center of the top, and the ridge is formed on the other side. The gist of the writing instrument cap is formed so as to be located in the region. In the writing instrument cap of the present invention, the air flow hole for preventing suffocation and the ridge for positioning when the writing instrument body is mounted are formed as far as possible from each other.
Even if a strong force is applied to the part forming the air circulation hole of the mold at the time of injection molding, the load on the part forming the ridge of the core pin can be minimized, so that the durability of the molding die is maintained. You can do it. An example will be described below with reference to the drawings.
FIGS. 1 to 4 show a cap A of a writing instrument of the present invention made of a synthetic resin such as polyethylene, polypropylene, polyethylene terephthalate, acrylonitrile styrene, acrylonitrile butadiene styrene, or polyamide. As shown in FIG. 1 which is a longitudinal sectional view, a cap A has a bottomed tubular writing instrument main body housing portion 3 composed of a hemispherical top 1 and a cylindrical straight portion 2, and an outer surface of the straight portion 2. And a clip portion 6 including a base portion 4 and a holding portion 5. An air flow hole 7 for preventing suffocation is formed on the top 1 of the writing instrument main body housing 3 so as to be shifted toward the clip portion 6 from the tip (center position) of the top 1. The size and shape of the air flow hole 7 may be any size as long as it is large enough to keep breathing even if a child or the like accidentally clogs the throat, but there are restrictions on product design and mold processing. It is desirable to consider easiness and the like. As shown in FIG. 2, which is a view in the direction of arrow I in FIG. 1, the air flow hole 7 of this embodiment is formed in a sector shape so as to secure a central portion of the top 1 with a large area. . If the central part of the top 1 is secured in a large area as described above,
In this area, the shape of the pen tip or the color of the handwriting can be displayed. Also, there is a problem with a writing instrument cap having an air hole for preventing suffocation. Ink may leak to the outside from the circulation hole,
In the case of the fan shape as in the present example, a portion serving as a certain amount of ink is formed at the bottom portion 10 of the inner hole 9, and there is an advantage that ink leakage to the outside of the cap does not easily occur. The writing instrument main body housing portion 3 has an inner hole 9 for accommodating a front portion of the writing instrument main body B on the pen tip 8 side, and a bottom portion 10 of the inner hole 9 is brought into contact with the writing implement main body B in abutting manner. A plurality of contacting ridges 11 are formed. The ridge 11 is formed as a thin wall in consideration of a sink phenomenon of the synthetic resin material during molding. The air flow hole 7 and the ridge 11 are formed at positions opposing each other with respect to a center line II passing through the center of the top 1. By doing so, the distance between the air flow hole 7 and the ridge 11 can be maximized, and the durability of the molding die can be ensured. As shown in FIG. 3 showing a state in which the writing implement main body B is mounted, the protruding ridge 11 abuts on a step formed on the writing implement main body. In the case of this example, the diameter of the inner hole of the cap A is slightly smaller than the outer shape of the writing implement body B, and the cap A is fitted by a so-called press-fitting method. The mounting position of the cap A and the writing implement main body B is determined by the contact between the ridge 11 and the step of the writing implement main body.
In this example, the step of the writing implement body B with which the ridge 11 abuts is the tip 13 of the holder 12 of the pen tip 8. FIG. 4 is a sectional view taken along the line III-III of FIG. As described above, the air flow hole 7 and the ridge 11 are formed at positions opposing each other with respect to a center line passing through the center of the top 1. Since the ribs are formed in this way, even when the cap A is stuck in the throat and the cap A is to be crushed in the direction in which the diameter is reduced due to an external force applied thereto, the ridge 11 becomes an obstacle and air It is also possible to prevent the flow holes from being closed. At this time, it is preferable that the ridges extend in the direction in which they oppose each other, and that when the diameter of the cap B is reduced, the most central portions 14 thereof come into contact with each other. FIG. 5 shows another embodiment. This is shown in a drawing corresponding to FIG. 2 of the above-mentioned example. In FIG. 5, the positional relationship among the clip portion 6, the air flow hole 7, and the ridge 11 of the cap A is changed from that of the above-described example. That is, the air circulation hole 7 is formed at a position farthest from the clip 6. Synthetic resin supply port 15 (a so-called gate port) of a molding die for molding the cap of this example.
Is formed at a position corresponding to the tip of the top 1 of the cap A. It is relatively difficult for resin to flow into the clip part, which is an irregular part of the outer shape during molding,
By forming the air flow holes 7 at the position farthest from the clip 6 as in the case of this example, the flow of the resin to the clip portion 6 is prevented so that the mold portion forming the air flow holes 7 does not become an obstacle. What was done. FIG. 6 shows still another embodiment. As in the case shown in FIG. 5, the flow of resin during molding is taken into account. That is, since the air circulation holes 7 are provided at two positions and no space is formed between the synthetic resin supply port 15 and the clip portion 6 at the same position as that described with reference to FIG. It can be said that it is a shape that is easy to mold while forming a flow hole. By doing so,
The clip portion 6 and the ridge 11 are not formed at the same position with the wall of the straight portion 2 interposed therebetween, so that a thick portion of the resin is hardly formed, a sink phenomenon is not easily generated, and a dimensionally stable molding is performed. It can also be a product. The cap of the writing instrument according to the present invention secures the air circulation hole for breathing and secures the cap even if a child or the like accidentally swallows the cap, and furthermore, forms the cap. The durability of the mold can be maintained.

[Brief description of the drawings] FIG. 1 is a longitudinal sectional view showing an embodiment. FIG. 2 is a view in the direction of arrow I of FIG. FIG. 3 is a longitudinal sectional view showing the embodiment. FIG. 4 is a sectional view taken along line III-III of FIG. FIG. 5 is a sectional view showing another embodiment. FIG. 6 is a sectional view showing still another embodiment. [Explanation of symbols] A cap B Writing instrument body 1 Top 2 straight part 3 Writing instrument body storage 4 Base 5 Holding part 6 Clip section 7 Air circulation holes 8 pen tip 9 inner hole 10 bottom 11 Ridge 12 holder 13 Tip 14 The most central part 15 Synthetic resin supply port

Claims (1)

(57) [Claims] [Claim 1] At the time of mounting on a writing instrument main body, a ridge is formed on the bottom to be positioned against each other by being abutted against the writing instrument main body, and air for preventing suffocation is formed on the top. In the cap of a writing instrument made of a synthetic resin provided with a flow hole, the air flow hole is formed in one area divided by a straight line passing through the center of the top, and the ridge is positioned in the other area. A writing instrument cap characterized in that the writing instrument cap is formed.