JPH0153168B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection mold apparatus equipped with a runner having a variable volume.

Conventionally, using this type of injection molding equipment,
To mold a molded product, as shown in Fig. 1, resin injected from an injection port 1 passes through a runner 2 and a gate 3, and then enters a plurality of cavities 6 formed in an upper mold 4 and a lower mold 5 and arranged in parallel in the horizontal direction. This is done by filling. However, when the cavity 6 is filled with resin, resin remains in the runner 2 and the gate 3, and the resin that cannot be recycled is often discarded, which significantly reduces the efficiency of resin utilization. . Therefore, one possible method to improve the efficiency of using this resin is to reduce the volume of the runner formed in the mold, but if the volume of the runner is reduced, the resin will clog inside the runner, and the resin will fill the cavity sufficiently. This has the disadvantage that it is not possible to provide a runner with a small volume because it may not be possible to do so, which causes defective molded products to be molded. Furthermore, the molding method itself has the drawback of increasing the number of steps and increasing costs.

The present invention was made in view of these circumstances, and includes a plurality of cavities arranged in parallel on one side, and a runner communicating with these cavities via a gate and having a volume approximately equal to the total volume of the cavities, A pressurizer that moves forward and backward in a direction perpendicular to the parallel direction of the cavities is installed inside this runner, and the volume of the runner can be varied by moving the pressurizer forward and backward.This extremely simple configuration increases resin usage efficiency and molds the runner. An object of the present invention is to provide an injection mold device that prevents the occurrence of defects in products. The configuration and the like will be explained in detail below with reference to embodiments shown in the drawings.

FIG. 2 is a perspective view showing the entire injection mold device according to the present invention, and FIG. 3 is a sectional view showing a state in which resin is injected into the runner. FIG. 4 is a sectional view showing the cavity filled with resin. In these figures, the same members as in FIG. 1 are designated by the same reference numerals, and detailed explanations will be omitted. In the figure, a runner 2 whose volume is variable is formed in an upper die 4 having openings at the upper and lower ends, and a gate 3 communicating with the cavity 6 is provided near the lower end. The volume of the runner 2 is approximately equal to the volume of the cavity 6 before injection of liquid resin or the like. Reference numeral 7 denotes a pressurizer that can move forward and backward in the vertical direction, and is provided so that a part thereof faces inside the runner 2 and the other part is exposed to the outside. By moving the presser 7 back and forth, the volume of the runner 2 is made variable during molding. 8 is a stopper that restricts the upward movement of the pressurizing element 7;
It is formed into a hook shape. A portion of this stopper 8 is fixed to the upper mold 4, and its tip engages with the presser 7. Reference numeral 9 denotes a spring that allows the presser 7 to move forward and backward, and is disposed between the presser 7 and the upper die 4, and always urges the presser 7 upward.

Therefore, as described above, since the spring 9 always urges the presser element 7 upward, the position of the presser element 7 is regulated by the stopper 8, and thereby the runner 2
The volume of the cavity 6 is approximately equal to that of the cavity 6. In this state, liquid resin is injected from the injection port 1 to fill the runner 2. Thereafter, as shown in FIG. 3, if the pressure element 7 is pressurized in the direction of the arrow with a press or the like so that its tip reaches the bottom of the runner 2, the liquid resin in the runner 2 will be released as shown in FIG. The cavity 6 is filled through the gate 3.

Although this example uses a liquid resin as the molding resin material, the present invention is not limited to this, and for example, weighed powdered resin or pelletized resin of a certain shape may be used. Of course, you can also use .

As explained above, the present invention includes a plurality of cavities arranged in parallel on one side, and a runner communicating with these cavities via a gate and having a volume approximately equal to the total volume of the cavities, and inside the runner. A pressurizer that moves forward and backward in the direction perpendicular to the parallel direction of the cavities is installed in the runner, and the volume of the runner can be varied by moving the pressurizer forward and backward. When pressurized, the presser moves in the direction of decreasing the runner volume, so the resin inside the runner is injected into the cavity through the gate, so the only resin that needs to be discarded is the resin inside the gate. This makes it possible to improve resin usage efficiency. Furthermore, since the step of discarding the resin in the runner is omitted, molding can be facilitated, and the cost of molding can be reduced.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the entire conventional injection mold, Fig. 2 is a perspective view showing the entire injection mold according to the present invention, and Fig. 3 is a runner in which resin is injected. FIG. 4 is a sectional view showing a state in which the cavity is filled with resin. Furthermore, since the resin in the runner can be pushed out into the cavity by the operation of the presser, a sufficient amount of resin can be supplied into the cavity, and it is also possible to prevent defects in the molded product. Furthermore, since the resin in the runner can be supplied into a plurality of cavities all at once, there is an advantage that the molding time can be significantly shortened when producing a large number of molded products. 2...Runner, 3...Gate, 4...Upper die, 5
...Lower mold, 6...Cavity.

Claims (1)

[Claims] 1. It has a plurality of cavities arranged in parallel on one side, and a runner that communicates with these cavities through a gate and has a volume approximately equal to the total volume of the cavities. An injection mold device characterized in that a pressurizer that moves forward and backward is provided, and the volume of the runner can be varied by moving the pressurizer forward and backward.