JPH09131764A - Nozzle mechanism with built-in sprue and runner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the yield of a product and the working efficiency of facilities by opening runners and a gate of a mold at the same time by a pres sure of a nozzle having a sprue and the runners integrated therein when the nozzle moves forward and pulling back and blocking the gate and a part of the runners by negative pressure after completion of injection when the nozzle retracts. SOLUTION: At a nozzle 7 of an injection molding machine, a plurality of runners 4 to be injected into each cavity 6 are provided. Interlocking forward movement of the nozzle 7 and its attachment to a mold with pressure, the runners 4 are opened and a gate 5 of the mold is also opened so as to perform injection. At that time, a negative pressure piston 9 is being lowered resisting a spring 10. Next, when the nozzle 7 is detached from the mold, a gate block 12 is pushed up by a spring 13 so as to block the gate 5 and a runner block 8 blocks the runners 4. The piston 9 is pushed back by the spring 10 and the materials of the gate 5 and the runner block 8 are pulled back into the runners 4 by negative pressure so as to be used for a next molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber or resin mold structure and an injection molding apparatus.

[0002]

2. Description of the Related Art As shown in FIG. 3, a nozzle of an ordinary injection molding machine is injection-molded through a sprue runner gate incorporated in a mold. The sprue runner gate is cut and regenerated or discarded by post-processing. . For this reason, the molding yield is deteriorated and the product cost is increased.

[0003]

It is an object of the present invention to eliminate the use of 100% of the material and post-processing such as gate cutting which could not be achieved by the conventional branching technique.

[0004]

[Means for Solving the Problems] When injection molding rubber or molten resin, a plurality of runners for injecting into each cavity are built in a nozzle of an injection molding machine, and when the nozzle advances and is crimped to a mold, In conjunction with this, the runner incorporated in the nozzle opens and the mold gate also opens and ejects, and when the nozzle is retracted when the injection is completed, some material of the mold gate and the runner of the nozzle is the nozzle. The solution is to provide a mechanism to be pulled back and closed by negative pressure.

[0005]

[Function] A block in which a runner is provided in the nozzle part and the runner is divided into two parts, and the nozzle is press-fitted to the mold, the runners are divided into two parts, and the gate of the mold is closed by a spring. The lowering gate is also opened. At the same time, when the nozzle is released, the spring of the piston that creates negative pressure is applied.

[0006]

Since the present invention is constructed as described above,
The sprue, runner, and gate in the mold, which were left and discarded in the conventional molding method, are no longer required, and the product yield can be improved up to 100%. Furthermore, by having a spare nozzle when changing materials, it is not necessary to raise or lower the mold, disassembling, etc., and the operating rate of the equipment can be greatly improved.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a state at the time of injection, in which the sprue (3), the runner (4), and the gate (5) open cooperatively to generate a negative pressure that pulls back part of the gate (5) and runner (4) into the nozzle. The spring (10) of the negative pressure piston (9) is in a pre-stressed state. 2 shows that the gate block (12) is pushed up by the spring (13) to close the gate (5) and slide downward along the slope when the injection is completed and the nozzle (7) is separated from the mold. The runner block (8) installed closes the moving runner (4) to the lower limit, and the negative pressure piston (9) is pushed back downward by the spring (10), and the gate (5) depends on the negative pressure generated. -Since the material of the runner block (8) is pulled back into the runner (4) and used for the next molding, a yield of 100% is achieved and post-processing such as gate cutting is also unnecessary, and ultimate rationalization can be achieved.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a mold and a nozzle showing an embodiment of the present invention, showing a state at the time of injection.

FIG. 2 is a vertical cross-sectional view of a mold and a nozzle showing one embodiment of the present invention, showing a state in which injection has been completed and the nozzle has been separated from the mold.

FIG. 3 shows a general structure of conventional injection molding.

[Explanation of symbols]

 (1) Upper mold (2) Lower mold (3) Sprue (4) Runner (5) Gate (6) Cavity (7) Nozzle (8) Runner block (9) Negative pressure piston (10) Spring (11) Holding screw (12) Gate block (13) Spring (14) Retaining screw

Claims (1)

[Claims] 1. In rubber or molten resin injection molding, a sprue and a runner conventionally provided in a mold part are incorporated in a nozzle, and the runner and the mold incorporated in the nozzle by utilizing the pressure when the nozzle advances. A mechanism that opens the gate of the part together and prevents material leakage, and a mechanism that pulls back and closes part of the material of the mold gate and nozzle runner by negative pressure by retracting the nozzle after injection is completed. A rubber or resin mold structure and a molding device comprising: