JPH0699463A - Metal mold apparatus for injection molding of molded product having plurality of parallel vanes - Google Patents

Abstract

PURPOSE:To set the thicknesses and the intervals of the formed bellows without the falling of divided plates by forming resin flowing paths in communication between the dividing plates in the vicinity of the outer source of a cavity part. CONSTITUTION:A core pin 4 is inserted into a central hole 3, which is formed of a semicircular holes 3a and 3b at the time of closing. A central resin path 5 in communication with dividing plates 2A and 2B from the inner side are formed at the outer surface parts of the core pin 4. Reinforcing pins 6a and 6b are inserted into longitudinal grooves 4a and 4b. Outer resin paths 7a and 7b in communication with the dividing plates 2A and 2B from the outside are formed. Resin is made to flow through upper sprues 8a and 8b of closed split metal molds 1A and 1B. The resin is split into the central resin path 5 and outer resin paths 7a and 7b and flows into the divided spaces between the respective dividing plates 2A and 2B from both the central part and the outer part. Therefore, short-circuit does not occur because the inflow amount of the resin can be increased.

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 in a writing instrument will be described. When injection molding the bellows arranged between the ink chamber and the pen tip to adjust the ink outflow amount of the conventional writing instrument, as shown in FIGS. 5 and 6, the split molds 10A, 10 are used.
A large number of split plates 11A and 11B are provided in parallel in the cavity of B 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 split bill. 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 prior art described above, as shown in FIG. 7, since the resin flows from the resin passage to the outer peripheral portion of the blade, the resin easily flows between the uppermost division plates, and as a result,
Since the dividing plate 2A ₁ is curved downward and the next dividing plate inlet is narrowed, the resin does not flow all the way to the inside, and the resin is not filled.
After that, a similar situation occurs, the blade gaps of the molded product become uneven, the thickness of the blades varies, and the amount of resin flowing between the blades decreases as it goes downward. -That will happen.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and a plurality of split plates are provided in parallel in the cavity of a pair of split molds, and a resin passage is provided near the center. In a mold device for injection molding of a molded product having a plurality of parallel blades configured to inject resin from the resin passage between the divided plates, between the divided plates in the vicinity of the outer periphery of the cavity part. It is characterized in that a resin flow passage communicating with each other is formed.

[0005]

1 and 2 show a first embodiment of the present invention. 1
A and 1B are left and right split dies, and a large number of split plates 2A and 2B are provided in parallel in the cavity portion at regular intervals, and semicircular holes 3a and 3b are formed at the center of the joining surfaces of the split dies 1A and 1B. To form
Longitudinal grooves 4 communicating on the outer peripheral portions of both sides between the respective dividing plates 2A and 2B
a and 4b are formed.

The core pin 4 is fitted into the center hole 3 formed by the semicircular holes 3a and 3b when the mold is closed, and the central portion resin which communicates with the outer periphery of the core pin 4 from the inside between the dividing plates 2A and 2B. A passage 5 is formed. 6a and 6b are reinforcing pins which are inserted into the vertical grooves 4a and 4b to form outer peripheral resin passages 7a and 7b which communicate with each other between the divided plates 2A and 2B from the outside.

Next, the operation will be described. The resin flows in from the upper gates 8a and 8b of the closed mold halves 1A and 1B. The resin is the central resin passage 5 and the outer peripheral resin passages 7a, 7
It branches into b and flows, and flows from both the central portion and the outer peripheral portion between the divided plates 2A and 2B.

FIGS. 3 and 4 show a second embodiment of the present invention, which is a split plate 2 for the cavity portions of the left and right split molds 1A ', 1B'.
Vertical grooves 4a 'and 4b' are formed near the outer peripheral portions of A'and 2B '. The other structure is similar to that of the first embodiment.

Next, the operation will be described. The resin flows in from the upper gates 8a 'and 8b' of the closed molds 1A 'and 1B'. The resin has a central resin passage 5'and vertical grooves 4a ', 4
It branches into b'and flows from both the central portion and the outer peripheral portion between the divided plates 2A 'and 2B'.

In the present invention, the core pin is provided so as to protrude from the center of the cavity, but it is not always necessary.

[0011]

According to the present invention, a large number of division plates are provided in parallel in the cavity portions of a pair of split molds, a resin passage is provided near the center, and a resin passage is provided between the division passages through the resin passage. In a mold device for injection molding of a molded product having a plurality of parallel blades designed to inject a resin, a resin flow path communicating between the divided plates is formed near the outer periphery of the cavity, so that Since the resin flows from the center and the outer periphery between the split plates that are installed in parallel at intervals, the injection pressure can be reduced compared to the conventional one, so the thickness and spacing of the bellows molded without the split plates falling over. Since it can be kept constant and the inflow of resin can be increased, there is no shortage.

[Brief description of drawings]

FIG. 1 is a front sectional view of a closed mold according to a first embodiment of the present invention.

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

FIG. 3 is a plan sectional view of a second embodiment of the present invention when the mold is closed.

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

FIG. 5 is a front cross-sectional view of a conventional device when it is closed.

6 is a plan sectional view taken along the line CC of FIG.

FIG. 7 is an explanatory view of an injection molding state of a conventional device.

[Explanation of symbols]

 1A Split mold 1B Split mold 1A 'Split mold 1B' Split mold 2A Dividing plate 2B Dividing plate 2A 'Dividing plate 2B' Dividing plate 3 Center hole 3a Semicircular hole 3b Semicircular hole 4 Core pin 4a Vertical groove 4b Vertical Groove 4a 'Vertical groove 4b' Vertical groove 5 Central part resin passage 6a Reinforcing pin 6b Reinforcing pin 7a Outer peripheral resin passage 7b Outer peripheral resin passage

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[Procedure amendment]

[Submission date] September 30, 1993

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 4]

[Figure 7]

[Figure 3]

[Figure 5]

[Figure 6]

Claims (1)

[Claims] 1. A pair of split molds are provided with a plurality of split plates in parallel in the cavity portions, a resin passage is provided near the center, and resin is injected from the resin passage between the split plates. In a mold device for injection molding of a molded product having a plurality of parallel blades, an injection of a molded product having a plurality of parallel blades in which a resin flow path communicating with each divided plate is formed in the vicinity of the outer periphery of the cavity Molding equipment for molding.