JP3829468B2 - 2-color molding soft resin runner release device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for preventing a soft resin runner from adhering to the inner surface of a mold when the mold is opened in a two-color molding apparatus.
[0002]
[Prior art]
Recently, a ballpoint pen has been required to add value, and rubber grips have been developed around the grip. Originally assembled as separate parts, the shaft part and the rubber grip part were molded at once as shown in FIG. 6 by two-color molding. Usually, most ballpoint pens have a tapered shape as shown in FIG. In this case, because the two-color molding moves to the secondary side with the primary product attached to the core, the secondary molded product is above the split mold as shown in FIG. There was no problem of sticking to one of the split molds because of its low power.
However, if the degree of freedom of the ball-point pen shape from the design is improved, a mold structure as shown in FIG. 8 must be formed in order to form a tip-shaped molded product as shown in FIG. In other words, when the rubber grip 101 is molded in two colors on the shaft 100 of the primary molded ballpoint pen, the second color soft resin has to run the runner 103 deep into the split mold 102. 104 is a runner gate, 105 is a core pin.
[0003]
[Problems to be solved by the invention]
In the above prior art, the runner 103 should originally be released from the molded product, but since the soft resin has strong adhesion to the split mold, it will stick to one side and tear the gate as shown in FIG. There was a problem.
[0004]
[Means for Solving the Problems]
The present invention aims to solve the above-mentioned problems, and is a mold apparatus for integrally forming a grip of a secondary molded product on the surface of a shaft of a cylindrical primary molded product, wherein a core pin is disposed on the mold. In the apparatus for forming a secondary molded product on the primary molded product in a state in which the primary molded product having a hollow portion in close contact with the core pin is in close contact with the core pin, the mold includes the first molded product. A secondary molding runner formed with a runner gate that communicates with the primary molding and forms a secondary molding is formed from the upper side of the primary molding downward, and the lower end of the secondary molding runner is While forming a runner gate, a ring hole that integrally forms a discard ring having a center hole is formed in the upper part of the runner for secondary molding, and the center hole is fitted into the protruding portion of the core pin protruding from the primary molded product. Characterized by being held together .
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail based on the illustrated examples.
1 to 4 show an embodiment of the present invention. 1 is a split mold, and a cylindrical primary molded product 3 such as a ballpoint pen shaft is in close contact with the core pin 2, and an annular cavity 4 formed on the outer periphery of the lower portion thereof. Reference numeral 5 denotes a soft resin runner formed downward from above, and its lower end communicates with the runner gate 6 of the cavity 4. A discard ring 8 having a center hole 7 is integrally formed on the upper part of the pair of runners 5, and the center hole 7 is fitted and held in a core pin protruding portion 9 protruding from the upper end of the primary molded product 3.
[0006]
Next, the operation will be described.
A soft synthetic resin is sent from the runners 5 and 5 to the lower part of the split mold 1 and injected into the cavity 4 from the runner gate 6. 3 and 4, the runner 5 is reliably released from the split mold 1 by the discard ring 8 held by the core pin 2 as shown in FIGS. 3 and 4, so that the runner 5 tilts and the gate 6 is cut or the inner surface of the split mold 1 is cut. It can be surely prevented from adhering and becoming impossible to take out.
[0007]
【The invention's effect】
The present invention is a mold apparatus for integrally forming a grip of a secondary molded product on the surface of a shaft of a cylindrical primary molded product, wherein a hollow portion is disposed in close contact with the core pin. In an apparatus for forming a secondary molded product on the primary molded product in a state in which the primary molded product formed with the core pin is in close contact with the core pin, the mold communicates with the primary molded product and the secondary molded product. The runner for secondary molding in which the runner gate is formed is formed so as to face downward from the upper side of the primary molded product, and the runner gate is formed at the lower end of the secondary molding runner , while the secondary molding is performed. Since a ring hole that integrally forms a discard ring having a center hole is formed on the upper part of the runner, and the center hole is fitted and held on the protruding portion of the core pin that protrudes from the primary molded product. Runner and core pin are united It can be released from the really split mold.
[Brief description of the drawings]
FIG. 1 is a front sectional view of an embodiment of the present invention at the time of injection molding.
FIG. 2 is a plan view taken along the line AA of FIG.
FIG. 3 is a side view of FIG. 1 opened.
4 is a plan view of FIG. 3. FIG.
FIG. 5 is a front view of a conventional tapered ballpoint pen.
6 is a front sectional view of the ball-point pen injection mold shown in FIG. 5;
FIG. 7 is a front view of a conventional thick ballpoint pen.
8 is a front sectional view of the thick ballpoint pen injection mold shown in FIG. 7. FIG.
FIG. 9 is a front view when the mold of FIG. 8 is opened.
FIG. 10 is a plan view of FIG.
[Explanation of symbols]
1 split mold 2 core pin 3 primary molded product 4 cavity 5 runner 6 runner gate 7 center hole 8 throw ring 9 core pin protrusion

Claims (1)

A mold apparatus for integrally forming a grip of a secondary molded product on the surface of a shaft of a cylindrical primary molded product, wherein a core pin is disposed in the mold and a hollow portion is formed in close contact with the core pin. In an apparatus for forming a secondary molded product on the primary molded product in a state in which the secondary molded product is in close contact with the core pin, the mold has a runner that communicates with the primary molded product to form a secondary molded product. A secondary molding runner formed with a gate is formed from the upper side of the primary molding downward and the runner gate is formed at the lower end of the secondary molding runner, while the upper part of the secondary molding runner is formed. in the discarded ring having a center hole to form a ring hole be formed integrally, the center hole of the two-color molding, characterized in that is fitted and held on the protruding portion of the core pin which protrudes from the primary molded article Soft resin runner release device.

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