NL2002118C - Injection mold for spraying tubes. - Google Patents

Description

Injection mold for spraying pipes DESCRIPTION: 5

FIELD OF THE INVENTION

The invention relates to an injection molding mold for spraying pipes, comprising a mold provided with a cavity and a supply channel for injection molding material connecting to the cavity at the location of an injection opening, as well as a reciprocally movable closing member, which is movable between a closed position , in which a closing part of the closing pin closes the injection opening, and a release position, in which the closing part of the closing pin releases the spray opening.

Prior art.

Such an injection mold is known from the European patent application EP 0 086 963 A. By using a closing pin which closes the injection opening of the cavity after the injection molding material has been injected into the cavity, no injection part 20 forms on the product as provided with molds of an injection channel is the case. This means that no spraying part needs to be removed after spraying. For spraying pipes, in addition to the displaceable sealing pin, a displaceable core is usually used which is displaceable in and out of the cavity, as well as displaceable ejections for pressing the formed pipe out of the cavity.

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Summary of the invention.

An object of the invention is to provide an injection mold of the type described in the preamble in which a tube can be injected with little moving parts and ejected from the mold. To this end, the injection mold according to the invention is characterized in that the closing pin is provided with a needle which extends from the closing part into the cavity and forms a core of the mold. The closing pin and core are thus designed as one component, so that only one moving component is required for forming the tube.

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An embodiment of the injection mold according to the invention is characterized in that the injection mold further comprises an ejector present in line with the closing pin, which is movable back and forth in a channel which is present in the cavity boundary wall opposite the closing pin, which ejection is provided with a central cylindrical recess into which the end of the needle is guided. The ejection thus also serves as a guide for the movable core formed by the needle, as a result of which the ejections in the center of the product can push against the product.

10 Brief description of the drawings.

The invention will be explained in more detail below with reference to an exemplary embodiment of the injection mold according to the invention shown in the drawings. Herein: Figure 1 shows the mold of the injection mold with the nozzle and the closing and ejecting pins;

Figure 2 shows a detail of the composition shown in Figure 1 with the closing pin in the release position during the injection molding of the material;

Figure 3 shows the composition with the closing pin in the closed position after injection molding; and

Figure 4 shows the mold in the open position during the ejection of the sprayed product.

Detailed description of the drawings, 25

Figure 1 shows a mold 1 with a supply channel 3 and closing and ejecting pins 5, 7 of an injection mold according to the invention. The mold 1 consists of two mold halves 9, 11 with a cavity 13 therein in the form of the product to be sprayed, in this case a tube. The mold 1 is provided with an injection opening 15 through which the liquid material is injected into the cavity. The material is supplied via the supply channel 3. This injection opening 15 can be closed by a closing part 17 of the closing pin 5. Figure 1 shows the closing pin 5 in the closed position.

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To be able to form a tube, a core 19 must be present in the cavity 13. It must be possible to remove this core 19 from the molded product after spraying in order to release the product. For this purpose the core 15 is formed by a needle which is attached to the closing part 17 of the closing pin 5. The free end of the core 15 is guided during the displacement of the closing pin 5 in a cylindrical recess 21 and the ejectors 7 are present.

In figure 2 the mold 1 with the closing pin 5 in the release position is shown in detail during the injection of liquid material into the cavity 13. The material is supplied via the supply channel 3. After the cavity 13 has been filled, the injection opening 15 is closed by the closing part 17 of the closing pin 5, see figure 3, and the material solidifies. After the material has solidified sufficiently, the die parts 9 and 11 are removed from each other and the core 19 is withdrawn, whereafter the ejectors 7 eject the shaped tube 23, see figure 4.

Although in the foregoing the invention has been elucidated with reference to the drawings, it should be noted that the invention is by no means limited to the embodiment shown in the drawings. The invention also extends to all embodiments deviating from the embodiment shown in the drawings within the scope defined by the claims.

Claims (2)

1. Injection molding mold for spraying pipes, comprising a mold provided with a cavity and a supply channel for injection molding material connecting to the cavity at the location of an injection opening, as well as a reciprocating closing pin, which is movable between a closed position, in which a closing part of the shut-off pin closes the inlet opening, and a release land, in which the shut-off part of the shut-off pin releases the spray opening, characterized in that the shut-off pin is provided with a needle extending from the shut-off part into the cavity and forming a core of the mold . 2. Injection mold according to claim 1, characterized in that the injection mold furthermore comprises an object which is present in line with the closing pin and which is movable back and forth in a channel which is present in the cavity boundary wall opposite the closing pin, which ejects is provided with a central cylindrical recess into which the end of the needle is guided.