JPH0435131Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a two-color mold for forming a product made of two-color resin.

[Prior Art] In recent years, plastic products such as type keys in which the letters and the key body are molded using resins of different colors, and cassette cases with different designs have been developed. Due to demand, products molded from two-color resin are becoming increasingly available.

By the way, there is a conventional mold for molding such plastic products as shown in FIG. The molds shown in these figures are for molding the cassette case A shown in FIG. Consisting of a core mold 2 and a core 4 provided so as to be freely retractable into the cavity 3 of the core mold 2 and the fixed mold 1,
After injecting and filling a transparent molten resin into the space 3a formed by the core 4 and forming the transparent resin part Pa, the core 4 is moved in the direction of the arrow X in the figure, and the fourth
As shown in the figure, colored molten resin is injected and filled into the space 3b occupied by the core 4, so that colored resin Pb can be molded.

By the way, in such a mold, when molding the transparent resin portion Pa, the peripheral edge of the end face of the core 4 is brought into contact with the inner surface of the fixed mold 2 to prevent the transparent resin from entering the space 3b occupied by the core 4. Therefore, the thickness of the peripheral edge of the colored resin portion Pb is always equal to the amount of movement of the core 4. Therefore, in the above-mentioned mold, for example, as shown in FIG.
cannot be molded.

Therefore, conventionally, as a mold for molding such a cassette case B, a rotary two-color molding mold as shown in FIG. 7 has been used.
The mold shown in this figure includes fixed molds 5 and 6 arranged at point-symmetrical positions across the axis O, and a mold movable toward and away from these fixed molds 5 and 6.
It is composed of two core molds 7, 7 of the same shape and size which are rotatably provided around the axis O, and the colored resin part Pb is formed by the fixed mold 5 and the core mold 7. After that, the colored resin part Pb is added to the core mold 7.
The transparent resin part Pa can be molded in the space formed by the cavities of the core mold 7 and fixed mold 6 and the colored resin part Pb by attaching and rotating this by 180 degrees.

[Problems to be solved by the invention] However, the above-mentioned mold requires two pairs of core mold and fixed mold, and also requires a mechanism to rotate the core mold. Not only does the mold become expensive, but manufacturing efficiency requires two injection molding operations and a rotation of the core mold to produce one plastic product, resulting in a significant drop in manufacturing efficiency.

This invention was made to solve these problems, and it not only reduces the cost of molds, but also greatly improves the manufacturing efficiency of plastic products. The purpose is to provide a molding die.

[Means for solving the problem] This invention has the following configuration to achieve its purpose. That is, the two-color molding die according to the present invention includes a first injection port for injecting and filling a molten resin into a space formed by a cavity and a core that can freely move in and out of the cavity, and a space occupied by the core. The second step is to inject and fill the molten resin into the
In a two-color molding mold comprising an injection port,
The core is composed of a main core and a sub-core that is in slidable contact with a side surface extending along the direction of movement of the main core and that is movable in the same direction as the main core, and these main cores and the secondary core,
A pin is provided that connects both cores so that they can move relative to each other over a predetermined distance, and that restrains the relative positional relationship of the sub-core to the main core when the main core is moved in a direction in which it is pulled out from the cavity and is stopped. It is characterized by:

[Example] An example of this invention will be described below with reference to Figures 1 and 2.
This will be explained with reference to the figures. FIGS. 1 and 2 are side sectional views showing a two-color molding die according to an embodiment.

The two-color mold shown in these figures has a fixed part 8
and a movable part 9 that is movable in a direction toward and away from the fixed part 8, and a cavity 12 formed by a fixed mold 10 and a core mold 11. It is now possible to mold plastic products by injecting molten resin into the interior. First, the movable part 9 will be explained. In the figure, reference numeral 13 is a movable side mounting plate. A receiving plate 15 is attached to this movable side mounting plate 13 via a spacer block 14, and a fixed mold 10 is attached to this receiving plate 15. A piston 16 whose one end protrudes toward the receiving plate 15 is disposed in the spacer block 14 so as to be slidable in the front-rear direction (in the direction of arrows X and Y in the figure). This piston 16 is moved in the front and back direction by hydraulic oil fed into hydraulic chambers 17 and 18 on both its front and rear sides.

Further, the receiving plate 15 is formed with a through hole 19 that opens at its front and rear end surfaces. The through hole 19 consists of a large diameter hole 20 on the side of the fixed mold 10 and a small diameter hole 21 on the opposite side, and a sub-core support 22 is slidable in the front and back direction in the small diameter hole 21. It is located. A sub-core 23 passing through the movable mold 11 is attached to the sub-core support 22 . The sub-core support 22 is connected to the piston 16 and moves in the front-rear direction as the piston 16 moves, causing the sub-core 23 to move in and out of the cavity 12.

In addition, a main core support 2 is provided in the large diameter hole 20.
4 are arranged so as to be slidable in the front and rear directions. A main core 25 that is in slidable contact with the side surface of the sub-core 23 is attached to the main core support 24 so as to penetrate through the movable mold 11 . The main core support 24 is connected to the sub-core support 22 by a plurality of pins 26 . The pin 26 has both ends enlarged in diameter into a flange shape,
The sub-core support 23 and the main core support 22 are connected so that they can be separated by a predetermined distance in the front-rear direction.

Based on this configuration, when the secondary core support 22 moves forward, the main core support 24 is pushed by the end face thereof and moves forward, and the secondary core support 22 moves backward by a predetermined dimension. At times, the secondary core support 22 moves while being hooked on the pins 26.
It is designed to move a dimension less than the amount of movement. The end surface of the main core 25 contacts the inner surface of the fixed mold 10 at the forward end of the main core support 24 and is at the same height as the inner surface of the movable mold 11 at the retreat end of the main core support 24. It's summery. In the figure, reference numeral 27 is an ejector plate, 28 is an ejector pin, and 29 is a return pin.

Next, the fixed part 8 will be explained. In the figure, reference numeral 30 is a fixed side mounting plate. A fixed mold 10 is attached to the fixed side mounting plate 30 via a stripper plate 31. The fixed mold 10 includes a cavity 12, a main core 25, and a sub-core 2.
A first injection port 33 opens into a space 32 formed by the main core 25 and the second injection port 34 opens into a space occupied by the main core 25 and the sub-core 23. Transparent resin and colored resin injected from sprue bushes 35 and 35 attached to the fixed side mounting plate 30 indicated by arrow Y are respectively injected from the respective injection ports 32 and 33.

Next, the procedure for molding the cassette case B shown in FIG. 6 using the two-color mold having the above configuration will be explained. First, the main core 25 and the sub-core 23 are made to protrude into the cavity 12, and their end faces are Transparent resin is injected from the first injection port 33 while the resin is in contact with the inner surface of the fixed mold 10. Then, the space 32 is filled with transparent resin to form the transparent resin portion Pa of the cassette case B. Next, as shown in FIG. 2, the piston 16 is moved in the direction of arrow X. Then, the sub-core 23 moves in the direction of arrow X,
Main core 25 then moves. In this case, the sub-core 23 is attached to the plate portion Pc of the cassette case B.
The main core 25 moves by a dimension equal to the thickness of the colored resin portion Pb. Next, colored resin is injected from the second injection port 34,
Molding the colored resin part Pb.

In the two-color mold with the above configuration, the sub-core 2
3 and the main core 25 by mutually different dimensions, the transparent resin part Pa and the colored resin part Pb of the cassette case B can be molded, so manufacturing efficiency can be greatly improved. Of course, one cassette case B can be manufactured using a pair of molds, and the molds can be made inexpensive.

[Effects of the invention] As explained above, the two-color molding mold of this invention has a first injection port for injecting and filling molten resin into the space formed by the cavity and the core that can freely move in and out of the cavity. , a two-color molding mold comprising a second injection port for injecting and filling the space occupied by the core with molten resin, in which the core is formed into a main core and a side surface extending along the moving direction of the main core; A sub-core that is slidably in contact with the main core and movable in the same direction as the main core, and connected between the main core and the sub-core so that both cores can move relative to each other over a predetermined distance. In addition, when the main core is moved in the direction of being pulled out from the cavity and stopped, a pin is provided to restrict the relative positional relationship of the sub core to the main core, and the primary resin is injected. Later, by moving the sub-core, the main core is moved to a predetermined position, and the pin is used to stop the sub-core at a predetermined position relative to the main core, thereby creating a product molded from the primary resin. It is possible to form a secondary resin-filled space having a part continuous with the part and a part continuous with and extending in a direction crossing the part. Therefore, with a very simple operation,
It is possible to manufacture plastic products having the above-mentioned complex shapes and made of two types of resin, and the manufacturing efficiency can be significantly improved. The advantage is that the mold can be manufactured at a lower cost.

[Brief explanation of the drawing]

1 and 2 are views showing one embodiment of the present invention, in which FIG. 1 is a side sectional view showing a two-color mold, and FIG. Figure 3 is a side sectional view showing an example of a conventional mold, Figure 4 is a diagram showing a state in which the core has been moved in Figure 3, and Figures 5 and 6 are a cassette case. FIG. 7 is a side sectional view showing an example of a conventional two-color mold. 3...Cavity, 3a...Space, 3b...Space, 4...Core, 12...Cavity, 23...
Secondary core, 25...Main core, 32...Space, 33...
...first injection port, 34...second injection port.

Claims (1)

[Scope of utility model registration request] A first injection port that injects and fills a space formed by a cavity and a core that can freely move in and out of the cavity, and a second injection port that injects and fills a space occupied by the core with a molten resin. In a two-color molding mold, the core is provided with a main core and a sub-core that is in slidable contact with a side surface extending along the moving direction of the main core and that is movable in the same direction as the main core. The core is connected between the main core and the sub-core so that both cores can be moved relative to each other by a predetermined distance, and when the main core is moved in a direction to be pulled out from the cavity and stopped. A two-color molding die, characterized in that a pin is provided to restrict the relative positional relationship of the sub-core to the main core.