WO1988006514A1

WO1988006514A1 - Device for guiding and apportioning extrudable substances

Info

Publication number: WO1988006514A1
Application number: PCT/DE1988/000115
Authority: WO
Inventors: Willi Riesle
Original assignee: Siegle, Karl
Priority date: 1987-03-05
Filing date: 1988-03-04
Publication date: 1988-09-07
Also published as: DE3725447A1

Abstract

Device for guiding and apportioning extrudable substances from, for example, an injection moulding machine to a tool. The flow of the substance is guided through boreholes (16) of variable cross-section, therefore of variable capacity, said boreholes piercing a basic structure (1) in a generally axial direction. Said basic structure (1) is provided with further boreholes (28) disposed in a generally radial direction and meeting the boreholes (16) at an approximately perpendicular angle, through which adjustable pins (25) are placed in the radial boreholes (28).

Description

Device for guiding and dosing extrudable material

The invention relates to a device for guiding and dosing extrudable material from, for example, an injection molding system to a tool, the material flow being guided through bores with a variable passage cross section and the bores passing through a base body in an approximately axial direction.

When producing workpieces, in particular by spraying, casting or extrusion, there is often the problem that the workpiece to be produced has an irregular, location-related material requirement. This applies above all to workpieces which should have an irregular profile. If, in this case, the material flow is introduced only at one point on the workpiece, the material must be distributed in the tool itself, which, given the speed at which such systems work, can lead to the positions which need more material, are not sufficiently supplied with material.

For this reason, there has recently been a move towards dividing the material flow between the extruder and the tool in order to be able to supply material to the tool at various points. Furthermore, it has already been planned to meter the individual material flows. A corresponding system is shown in European Patent 31 742. There, an axially movable slide is provided which has a cylindrical sliding body which is provided with a radial projection, which in turn lies opposite a truncated cone. The inclined surfaces of the truncated cone and the projection run parallel to one another and can be displaced relative to one another, the distance between the two inclined surfaces determining the passage cross section.

This head designed in this way has a complicated structure and is very difficult to handle. In order to adjust the slide, the tool must be removed from the end face of the head, so that metering of the material flow during operation is not possible. Another problem is that between the first and the second tool part of the first tool, ie before the mold exit, a considerable mixing of extrudable material takes place, for example, by gravity more material flows down from the upper holes, so that it in material jams in the upper area, while insufficient material is conveyed by the lower holes.

The inventor has set himself the goal of developing a device of the type mentioned above, which is of simple construction and makes dosing possible even without removing the tool and forcing it from the beginning to the end of the extrusion head. Furthermore, controlled temperature control should be possible for this device.

To achieve this object, the base body has approximately radial bores which meet the bores approximately perpendicularly, displaceable pins being inserted into the radial bores.

This means that the radial arrangement of the radial bores or the pins passing through them allows these pins to be displaced from the outside without the need to dismantle a tool or the system to stand still. Furthermore, the pins alone determine the passage cross-section of the bores, so that it is already visible from the outside how deep the pin penetrates into the bore, ie how far it has already narrowed the cross-section of the bore. If the pin penetrates the hole completely, two segments remain on the side, through which a material flow remains possible. If desired, the radial bore can also have markings via which the depth of the inserted pin can be read.

The pin preferably has a threaded section with which it meshes an internal thread in the radial bore. In this way, the pin can be moved in the radial bore, its end protruding into the bore for the material flow determining the passage cross section.

In a preferred embodiment, the base body is to be formed in one piece and consist of a mounting plate, a mounting plate and a ring connecting these two elements. The mounting plate is used in particular to fix the entire head to, for example, the outlet of an injection molding machine. The platen should in turn be suitable to carry a corresponding tool. For the arrangement of the radial bores, the mounting plate is provided in the exemplary embodiment shown, since the ring, together with a ring, serves as an annular channel for guiding a medium which determines the temperature of the head, and the clamping plate holds a nut for fixing the tool. However, the invention should not be limited to this, but the radial bores can also be provided elsewhere, provided that a suitable space is created for this. When dividing the material stream into individual streams, it is also important that these streams are kept at a certain temperature level even during or after dosing. The annular duct described in more detail above is used to introduce such a heating or cooling medium. A corresponding medium is constantly applied to the entire bores, in the present example arranged in a division of twelve.

It is also provided that this heating or cooling medium can also be guided via radial bores from the ring channel to channels in the base body or a distributor cone. As a result, temperature regulation takes place in the entire device.

In the position of use, the distributor cone engages in the outlet of the injection molding machine, the material flow striking its outer surface. This stream of material is spread out and supplied in a suitable manner to the entrance to the bore. To connect the distributor cone to the base body, a simple screw bolt is provided which passes through the base body and meshes a thread in the distributor cone, so that it attracts the distributor cone with its base surface, the base body. If it is necessary to seal this gap, an annular seal is provided here.

For better centering of the tool, the base body or the clamping surface has a disk-shaped recess in which the tool consisting of two parts in the present exemplary embodiment is inserted. Of course, other arrangements are also conceivable here, for example an injection molding machine with a fixed and a movable mold half can be taken into account.

If it proves necessary, there is also a connection nipple in the front area of the device for introducing supporting air between the two tool parts.

This simply constructed device effectively allows the material flow to be metered in such a way that it can be introduced in different thicknesses at different positions of the tool. It is also subject to uniform temperature regulation over its entire route.

Furthermore, guide channels are to be provided in the tool part which follows the bores and which has a mold exit, which connect the bores to the mold exit.

As a result, the bores are basically extended up to the mold exit, so that a positive guidance up to there remains guaranteed. Until the mold emerges, material is transported separately in each bore or in each guide channel, so that it cannot mix. It retains its position until the mold exit. It is therefore possible to dose the material depending on the location of the product to be sprayed. The guide channels are preferably delimited by guide walls which are aligned in a star shape towards the center of the mold outlet. This guidance along guide walls takes place up to a corresponding circumferential edge, which circumscribes a square in the following drawings. The guide channels or guide walls should preferably be molded into the material of the corresponding tool part. This makes it easier to center the corresponding guide channels with the bores. However, it can also be considered to form the guide channels or guide walls into an insert which is then inserted into an annular recess of the tool part. This embodiment makes it possible to use inserts with differently shaped guide channels as required.

To fix the insert and also to connect to the other tool part of the first tool, the second tool part has a shoulder encircling the annular recess, which serves as a stop for the first tool part. This simple measure creates a quantity-controlled material transport from the inlet into the corresponding bores to the mold exit.

Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawing; this shows in

1 shows a head, shown partly in cross section, for an injection molding machine;

Fig. 2 is a plan view of the head of Fig. 1 from the injection molding machine;

3 shows an enlarged interior view of a tool part;

Fig. 4 shows a cross section through Fig. 3 along the line IV-IV.

1, the head R has a base body 1 for an injection molding machine or the like extrusion plant. This base body 1 consists essentially of a mounting plate 2 and a mounting plate 3, which are connected to one another via a ring 4. Mounting plate 2, mounting plate 3 and ring 4 are advantageously made in one piece.

According to FIG. 2, mounting holes 5 are provided in the mounting plate 2, via which the head R can be fixed at the outlet of an injection molding machine by means of corresponding fastening elements. A distributor cone 6, which has a central blind hole 7 with an internal thread 8, projects into this outlet. This internal thread 8 meshes with a threaded shaft 9 of a screw bolt 10, which passes through an axial bore 11 in the base body 1 and whose screw head 12 strikes against a shoulder 13 formed in the axial bore 11. By means of the screw head 12, the distributor cone 6 is pressed firmly onto the end face 14 of the mounting plate 2, an annular seal 15 also being provided for sealing.

In the area of the ring 14, a number of bores 16 are provided in the base body 1, these bores 16 collecting in a circle parallel to the axial bore 11. According to the embodiment of FIG. 2, twelve such bores are provided.

The bores 16 also break through a tool part 17 placed on the clamping plate 3. This tool part 17 is encompassed by a second outer tool part 18, a corresponding disk-shaped recess 19 being provided in the clamping plate 3 for centering it. The tool part '17, on the other hand, has a circumferential rising surface 20, the shape of which is adapted to the inner surface 21 of the tool part 18.

In the position of use, an annular nut 23, which is placed on a thread 24 on the circumference of the clamping plate 3, presses onto an annular flange 22 formed by the second tool part 18.

To reduce the passage cross section of the bores 16, these radially piercing pins 25 are provided in the mounting plate 2. Each pin 25 has a threaded section 26 which meshes an internal thread 27 in the radial bore 28. In Fig. 2 it is shown that the one pin 25a is retracted so far that it almost completely clears the passage cross section of the bore 16. The other setscrew 25b, on the other hand, completely penetrates the passage cross section d of the bore 16, so that only two small lateral segments 29 are available as a passage for the material to be extruded.

The ring 4 is surrounded by a hoop 30, which includes an annular channel 31 with the outer circumference of the ring 4. A medium for temperature control of the head R can be guided in this ring channel 31. Corresponding radial bores 34 are provided for distributing this medium, in particular also into corresponding channels 32 of the distributor cone 6 or 33 of the basic body 1. At 35, a connection nipple for supporting air is also provided, which leads via a line 36 indicated by dashed lines to corresponding cavities in the tool. 3 and 4 a further embodiment of a second tool part 18a is shown. In this tool part 18a, the rising surface 20a is frustoconical with a rectilinear lateral surface. The tool part 17 fits into the space delimited by this rising surface 20a, abutting a shoulder 40. The tool part 17 is shown only weakly in FIG. 4. The continuations of the bores 16 through the tool part 17 are indicated by the dashed lines.

On the shoulder 40 there follows an annular recess 41 in which an insert 42 is seated. This insert 42 has guide channels 43 directed in a star shape towards a center M, which are delimited by corresponding guide walls 44. These guide channels 43 are aligned in the direction of a mold exit 45 and are connected to a bore 16 at the other end. - Λ Λ -

For the sake of simplicity, the mold exit 45 is square in the present case, but it can also have other shapes.

By means of these guide channels 43, it is avoided that the amount of material flow regulated up to that point is again mixed in the area between the two tool parts 17 and 18a.

Claims

1. Device for guiding and dosing extrudable material from, for example, an injection molding system to a tool, the material flow being guided through bores with a variable passage cross section and the bores passing through a basic body in an approximately axial direction,

characterized,

that the base body (1) has approximately radial bores (28) which meet the bores (16) approximately perpendicularly, displaceable pins (25) being inserted into the radial bores (28).

2. Device according to claim 1, characterized in that the pins (25) have a threaded portion (26) auf¬ with which they mesh an internal thread (27) in the radial bore (28).

3. Apparatus according to claim 1 or 2, characterized gekenn¬ characterized in that the base body (1) in one piece from a mounting plate (2), a platen (3) and a 'this connecting ring (4) is formed, the bores (16th ) pull the base body (1) in the area of the ring (4), while the radial bores (28) are provided in the mounting plate (2).

■ 4. Apparatus according to claim 3, characterized in that the ring (4) is surrounded by a hoop (30) with the formation of an annular channel (31) in which a heating or cooling medium can be guided.

5. The device according to claim 4, characterized in that from the annular channel (31) radial bores (34) to channels (32 or 33) in the base body (1) or in a distributor cone (6).

6. The device according to claim 5, characterized in that the distributor cone (6) via a screw bolt (10) with the base body (1) is connected.

7. The device according to at least one of claims 1 to 6, characterized in that the base body (1) or the platen (3) has a disc-shaped recess (19) in the front, in which a tool part (17) is inserted, which of a second tool part (18) is encompassed, which has an annular flange (22) on which an annular nut (23) presses, which is attached to a thread (24) on the base body (1).

8. The device according to claim 7, characterized in that a connecting nipple (35) for introducing supporting air between the two tool parts (17, 18) is provided.

9. Apparatus according to claim 7 or 8, characterized gekenn¬ characterized in that in the tool part (18a), which follows the bores 816) and which has a mold exit (45), guide channels (43) are provided, which connect the bores (16) to the tool mold outlet (45).

10. The device according to claim 9, characterized gekennzeich¬ net that the guide channels (43) are delimited by guide walls (44) which are aligned in a star shape towards the center (M) of the mold outlet (45).

11. The device according to claim 9 or 10, characterized in that the guide channels (43) or the guide walls (44) in the material of the tool part (18 a) are molded.

12. The apparatus of claim 9 or 10, characterized in that the guide channels (43) or the guide walls (44) are formed in an insert (42),. which fits into an annular recess (41) of the tool part (18a).

13. The apparatus according to claim 12, characterized gekenn¬ characterized in that the tool part (18a) has a .mund the .mund. Shoulder (40) for stop another part of the bores (16) having "tool part (17).