JPH05131499A - Injection-molding apparatus for molded item having a plurality of parallel blades - Google Patents

Abstract

PURPOSE:To prevent the deformation of a molded bellows caused by a pulling action of one mold by providing a reinforcing pin that acts to prevent the deformation of molding during mold releasing period in the vicinity of the outer periphery of a mold cavity in the case of injection-molding bellows or the like for controlling the ink flux quantity of a writing utensil. CONSTITUTION:On the cavity parts of split-molds 1A, 1B, a number of partition plates 2A, 2B are projectingly provided in parallel at predetermined intervals and semicircular holes 3a, 3b are formed on the central parts of tapered surfaces and reinforcing pin fitting notched holes 6a, 6b are formed in the bellows outer peripheral part at both sides thereof. The molds 1A, 1B are closed and, in the formed central hole 3 and reinforcing pin fitting hole 6, a core pin 4 and rectangular rod-shaped reinforcing pin 7 are inserted respectively. Then, resin is injected from pouring gates 8A, 8B for forming bellows 5. When the molds 1A, 1B are opened, the molded bellows 5 is obstructed in its movement by the core pin 4 and reinforcing pin 7 and thereby the bellows 5 are not deformed by the pulling action of one mold even in the case where the partition plates 2A, 2B and bellows 5 are different in their chamfers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding of a molded product having a plurality of parallel blades, for example, a temporary ink reservoir member (hereinafter referred to as a bellows) provided in a writing instrument, an ink jet of a printer, or the like. Regarding the device.

[0002]

2. Description of the Related Art As an example, a method of forming a bellows used for a writing instrument will be described. When injection molding the bellows arranged between the ink chamber and the pen tip for adjusting the ink outflow amount of the conventional writing instrument, as shown in FIGS. 9 and 10, the split molds 10A, 1 are used.
A large number of split plates 11A and 11B are provided in parallel in the cavity of 0B at regular intervals (about 0.3 mm), and the core pin 13 is inserted into the pair of split die joint surface center holes 12 to split the bill. The resin was injected from the sprue 14A, 14B above the molds 10A, 10B between the outer periphery of the core pin 13 and the dividing plates 11A, 11B.

[0003]

In the above prior art, the resin is injected into the narrow gap of the bellows with a considerable pressure,
After molding, the resin bites on each of the split plates that form the bellows in a state close to adhesion, and there will inevitably be a difference in the biting force between the left and right split plates. Therefore, when the split mold is opened left and right, the bellows 14 integrally formed as shown in FIGS. 11 and 12 is pulled toward, for example, the left split mold 10A, which is often eaten, and the thin core pin 13 is bent leftward. However, there is a problem in that the bellows 14 that is bent or formed is also deformed and often becomes a defective product.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by forming a plurality of parallel blades in which a plurality of parallel dividing plates are provided in the cavity of a pair of split molds. In a mold device for injection molding of a product, a reinforcing pin for preventing deformation of the molded product when the split mold is opened is arranged near the outer periphery of the cavity.

[0005]

EXAMPLE A first example of the present invention shown in FIGS. 1 to 4 will be described below. 1A and 1B are left and right split molds, and a large number of division plates 2A and 2B are provided in parallel in the cavity portion at regular intervals, and semicircular holes 3a and 3b are formed in the center of the surface of the patella. Reinforcing pin fitting cutout holes 6a, 6a,
6b and 6b are formed, the core pin 4 is fitted and inserted in the center hole 3 when the mold is closed, and the rectangular reinforcing pin fitting holes 6 and 6 are fitted with the rectangular rod-shaped reinforcing pins 7 and 7, respectively.

Next, the operation will be described. Split mold 1A,
1B is closed, a core pin 4 is fitted and inserted into a center hole 3 formed in the center of the surface of the part, and rectangular reinforcing pin fitting holes 6 and 6 formed on both sides of the core pin 4 are square rod-shaped reinforcing pins 7. , 7 are fitted together, and the outer periphery of the core pin 4 and the dividing plate 2 from the gates 8A, 8B.
Resin is injected between A and 2B to form the bellows 5.

When the split molds 1A and 1B are opened as shown in FIGS. 3 and 4, the center portion and both side portions of the molded bellows 5 are prevented from moving by the core pin 4 and the reinforcing pins 7 and 7. Therefore, even if there is a difference in the biting between the split plates 2A and 2B of the split molds 1A and 1B and the formed bellows 5, the bellows 5 is not deformed by being pulled by one split mold.

FIG. 5 shows a reinforcing pin 1 according to a second embodiment of the present invention.
7 and 17 are round pins.

FIG. 6 shows a reinforcing pin 2 according to a third embodiment of the present invention.
7, 27 are arranged at the inner surface of the bellows 5 to be molded.

FIG. 7 shows a fourth embodiment of the present invention, in which a reinforcing pin 3 is used.
7 and 37 are square bars having ridges 37a and 37a, and the ridges 37a and 37a are located on the bellows outer peripheral part surface.

FIG. 8 shows a fifth embodiment of the present invention, in which a reinforcing pin 4 is used.
7, 47 are located in the open-side bellows of the core pin. The operation is similar to that of the first embodiment.

The present invention can be applied not only to the bellows used for writing instruments but also to the bellows molding method for ink jets installed in a printer or the like.

[0013]

According to the present invention, in a mold device for injection molding of a molded article having a plurality of parallel blades, each of which has a plurality of parallel division plates protruding from the cavity of a pair of split molds, Reinforcing pins that prevent deformation of the molded product when the mold is opened are placed near the outer periphery of the cavity, so when opening the left and right split molds, the molded bellows and the split plate of the left and right split molds. Even if there is a difference in biting between the and, the deformation of the bellows is prevented, and the generation of defective products can be prevented.

[Brief description of drawings]

FIG. 1 is a front sectional view of a first embodiment of the present invention during molding.

FIG. 2 is a plane sectional view taken along the line AA of FIG.

FIG. 3 is a plan cross-sectional view when the mold is opened.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a plan sectional view of the second embodiment of the present invention when the mold is open.

FIG. 6 is a plan sectional view of the third embodiment of the present invention when the mold is opened.

FIG. 7 is a plan sectional view of a fourth embodiment of the present invention when the mold is opened.

FIG. 8 is a plan sectional view of the fifth embodiment of the present invention when the mold is opened.

FIG. 9 is a front cross-sectional view of a conventional device during molding.

10 is a cross-sectional view taken along the line CC of FIG.

FIG. 11 is a plan cross-sectional view when the mold is opened.

12 is a sectional view taken along line DD of FIG.

[Explanation of symbols]

 1A Split mold 1B Split mold 2A Dividing plate 2B Dividing plate 3 Center hole 4 Core pin 5 Bellows 6 Reinforcement pin fitting hole 7 Reinforcing pin 17 Reinforcing pin 27 Reinforcing pin 37 Reinforcing pin 47 Reinforcing pin

[Procedure amendment]

[Submission date] October 26, 1992

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

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FIG. 11

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Claims (1)

[Claims] 1. A mold device for injection molding of a molded article, comprising a plurality of parallel blades, each of which has a plurality of parallel division plates projecting from the cavity of a pair of mold halves. A mold device for injection molding of a molded product having a plurality of parallel blades, wherein a reinforcing pin for preventing deformation of the molded product is arranged in the vicinity of the outer periphery of the cavity.