Injection nozzle for injection-moulding machines

(42) Date of commencement of the patent: 15. 6.1990 (45) Date of issue: 10.12.1990 (56) References:

(73)

Patentee:

AT-PS 342287 AT-PS 342857 DE-OS 2342789 DE-OS 2445112 ENGEL MASCHINENBAU SOCIETY MBH

EP-A2 0261350 GB-PS 1332883 GB-PS 1219097 A-4311 SCHWERTBERG, UPPER AUSTRIA (AT).

(54) SPRAYING NOZZLE FOR INJECTION MOLDING MACHINES (57) A spray nozzle for injection molding machines for producing injection molded parts consisting of several plastic components. It has a nozzle body (1), an axially displaceable sleeve (7) and a within the sleeve (7) displaceable closing needle (8). The sleeve (7) is provided with a plurality of axially offset passage openings (11,12,13) ​​for melt streams. The nozzle body (1) has a plurality of off-center arranged Schmelzeleitkanäle (4,5,6) with axially offset outlet openings on the sleeve wall. In the nozzle body (1) tubular inserts (2,3) are arranged immovably, delimiting the Schmelzeleitkanäle (4,5,6).

<img file="AT391833B_D0001.tif" />

CQ

AT 391 833

MR «078003

No. 391 833

The invention relates to a spray nozzle for injection molding machines for the production of injection molded parts consisting of several plastic components, comprising a nozzle body, a sleeve axially displaceable therewith and a closing needle which can be displaced within the sleeve and which can be acted on by hydraulic pistons.

From AT-PS 342 287 a method for producing a shaped article from injection-molded plastic material has become known in which two different plastic materials from two injection cylinders are injected into a common mold, so that one obtains a molded part which has an outer layer and a core material. The nozzle is designed as a two-way valve and switchable so that either plastic material from one or the other mass cylinder can be injected into the mold.

Similar methods are described in British Patent Nos. 1219097 and 1332883.

From DE-OS 23 42 789 a device for the discontinuous production of MehrschichtFormkörpem made of plastic has become known, which has an axially displaceable sleeve in a nozzle body and within the sleeve an axially displaceable closing needle. By means of this device injection molded parts can also be produced from two different plastic components.

The object of the invention is to improve a spray nozzle of the type mentioned in that more than two plastic components can be injected and that it is possible to inject the plastic components both alternately and in parallel, ie at the same time.

The object of the invention is achieved in that the sleeve is provided with a plurality of axially offset passage openings for melt streams and the nozzle body has eccentrically arranged Schmelzeleitkanäle with axially offset outlet openings on the sleeve wall in a conventional manner.

An embodiment of the invention provides that tubular inserts are arranged immovably in the nozzle body, which delimit the Schmelzeleitkanäle. As a result, annular melt channels are formed in a structurally simple manner.

The axial displacement of the sleeve and the closing needle via hydraulic piston, which is advantageously provided that the hydraulic piston is guided in a floating cylinder, wherein in the floating cylinder on the piston rod side of the hydraulic piston, a floating piston can be inserted.

Thereby, the needle and the sleeve are independently movable, whereby emptying of the sleeve by the needle or the nozzle and the tubular inserts through the sleeve and the needle is possible.

Advantageously, it is provided that the passage openings in the sleeve in the longitudinal direction of the sleeve are longer than the outlet openings of the Schmelzeleitkanäle.

The longitudinal opening in the sleeve parallel operation is possible, ie a simultaneous emergence of the melt from multiple channels. Furthermore, a continuous transition from component A to component B is possible.

Hereinafter, an embodiment of the invention will be described with reference to the figures of the accompanying drawings.

1 to 8 each show a longitudinal section through a spray nozzle according to the invention, wherein different positions of the axially displaceable sleeve and the closing needle are shown, Fig. 9 shows a further section through the spray nozzle according to the invention, wherein the sleeve and the closing pin acted upon piston-cylinder units are drawn, and Fig. 10 shows a longitudinal section through a piston-cylinder unit for acting on the sleeve or the closing needle.

The spray nozzle according to the invention consists of the nozzle body (1), the two tubular inserts (2), (3), the middle axially displaceable sleeve (7) and the closing needle (8).

The tubular inserts define melt guide channels (4), (5), (6) for three different plastic components.

In the Schmelzeleitkanäle (4), (5), (6) open feed channels (14) for plasticized plastic, to which a Schneckenplastifiziereinheit not shown is connected.

The melt guide channel (4) is formed between the nozzle body (1) and the tubular insert (2), the melt guide channel (5) between the two tubular inserts (2) and (3) and the melt guide channel (6) for the third plastic component between the inner tubular insert (3) and the axially displaceable sleeve (7).

The axially displaceable sleeve (7) is provided with three offset in the axial direction through openings (11), (12), (13) for the plastic melt.

The tubular inserts (2), (3) have conical tips (15), (16), whereby in each case a funnel-shaped annular gap (17), (18) is formed. The gap (17) forms the outlet of the Schmelzeleitkanals (4) and the gap (18) the outlet of the Schmelzeleitkanals (5).

The Fig. 1 shows the spray nozzle in the closed position. The outlet openings for the Schmelzeleitkanäle (4) and (5) are shut off from the sleeve (7), while the Schmelzeleitkanal (6) through the closing needle (8) is closed. The passage openings (11), (12) of the sleeve (7) are located in the region of a wall of the nozzle body (1) or the outer insert (2) and the passage opening (13) is closed by the closing needle (8). None of the three plastic components can escape through the outlet opening (19) of the spray nozzle.

-2Nr. 391 833

Fig. 2 shows the spray nozzle in the injection position for the component (A). The sleeve (7) is retracted so far that the passage opening (11) allows the melt passage from the Schmelzeleitkanal (4) in the sleeve channel (20) and the nozzle channel (21).

The outlet opening of the Schmelzeleitkanals (5) of the sleeve (7), and the outlet opening of the Schmelzeleitkanals (6) is blocked by the closing needle (8).

In the nozzle position of Fig. 3, the plastic component (B) is injected.

The sleeve (7) is in its foremost position and closes the outlet openings of the components (A) and (C). The closing needle (8) is withdrawn and releases the passage opening (13) so that plastic of the component can enter the sleeve channel (20) from the melt guide channel (6).

The position of the sleeve (7) and the closing needle (8) in Fig. 4 allows the simultaneous injection of the plastic component (A) and the plastic component (B). The closing needle (8) is retracted so far that it releases the passage opening (13) in the sleeve (7), and the sleeve (7) is in the same position as in Fig. 2, so that the passage opening (11) before the annular gap (17) of the melt channel (4) is located. The melt channel (5) is blocked by the sleeve (7).

The position of the sleeve (7) and the closing needle (8) shown in FIG. 5 allows the simultaneous injection of the plastic components (A) and (C).

The passage opening (13) for the melt conduction channel (6) of the component (B) is closed by the closing needle (8). However, the passage openings (11) and (12) are in front of the funnel-shaped outlet openings (17), (18) of the Schmelzeleitkanäle (4) and (5).

According to FIG. 6, all three plastic components (Α), (B), (C) can be sprayed simultaneously.

The position of the sleeve (7) corresponds to the position of Fig. 5, and the closing needle (8) is further retracted, so that the passage opening (13) is released.

The position of the sleeve (7) and the closing needle (8) shown in FIG. 7 enables the sole injection of the component (C).

The sleeve (7) is retracted to the extent that the Schmelzeleitkanal (5) is released, while the front end of the sleeve (7) blocks the outlet region of the Schmelzeleitkanals (4). The passage opening (13) is in turn blocked by the closing needle (8).

The following table shows the different sleeves and needle settings as well as the injected plastic component.

Sleeve - Needle - 4 positions

<td colspan="4">SollkomDonente</td><td colspan="8" rowspan="2">sleeve setting</td><td colspan="8" rowspan="2">needle setting</td>

<td colspan="4">attitude</td>

<td colspan="2">Komnonen</td><td>th</td><td rowspan="2">Para.</td><td rowspan="2">1</td><td rowspan="2">2</td><td rowspan="2">3</td><td rowspan="2">4</td><td rowspan="2">5</td><td rowspan="2">6</td><td rowspan="2">7</td><td rowspan="2">8th</td><td rowspan="2">1</td><td rowspan="2">2</td><td rowspan="2">3</td><td rowspan="2">4</td><td rowspan="2">5</td><td rowspan="2">6</td><td rowspan="2">7</td><td rowspan="2">8th</td>

<td>A</td><td>C</td><td>B</td>

<td></td><td></td><td></td><td>1</td><td>1</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>1</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>A</td><td></td><td></td><td>2</td><td></td><td>2</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>1</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td></td><td></td><td>B</td><td>3</td><td></td><td></td><td>1</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>2</td><td></td><td></td><td></td><td></td><td></td>

<td>A</td><td></td><td>B</td><td>4</td><td></td><td></td><td></td><td>2</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>2</td><td></td><td></td><td></td><td></td>

<td>A</td><td>C</td><td></td><td>5</td><td></td><td></td><td></td><td></td><td>3</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>2</td><td></td><td></td><td></td>

<td>A</td><td>c</td><td>B</td><td>6</td><td></td><td></td><td></td><td></td><td></td><td>3</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>3</td><td></td><td></td>

<td></td><td>c</td><td></td><td>7</td><td></td><td></td><td></td><td></td><td></td><td></td><td>4</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>3</td><td></td>

<td></td><td>c</td><td>B</td><td>8th</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>'4</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>4</td>

The closing needle (8) and the sleeve (7) are acted upon by multi-stage piston-cylinder units (22), (23), wherein the piston-cylinder unit (22) via the piston rod (24) acts on the closing needle (8) and the piston-cylinder unit (23) via the Piston rod (24 '), the sleeve (7).

Fig. 10 shows a section through the piston-cylinder unit (22), the piston-cylinder unit (23) is formed the same.

The cylinder tubes (25), (26) are provided with hydraulic connections (27), (28) and in the cylinder tube (25) located floating cylinder (29) has a hydraulic connection (30).

The piston (31) with the piston rod (24) can be brought into four different positions by means of the floating cylinder (29) and the floating piston (32) in the cylinder tubes (25), (26).

By combining the piston positions for the closing needle (8) and the sleeve (7) according to the table, the plastic component to be sprayed can be selected.

-3Nr. 391 833