Patent Description:
The connecting plate is provided with three upstream-side flow paths that penetrate the connecting plate to guide elastomeric materials provided from the extruders. The head further includes three downstream-side flow paths which extends along respective boundaries between the split heads which are adjacent in up-and-down direction. The downstream-side flow paths are connected to the respective upstream-side flow paths on a one-to-one basis.

In this type of device, the size of the upstream-side flow paths to be communicated with the extruders is set according to the size of the extruders required. In addition, the shape of the downstream-side flow paths is set according to the shape to be extruded by a pre-former, die, etc..

As a result, when changing the size of the extruders later, it is necessary to remove the connecting plate from the fixed split head and additionally process the upstream-side the flow paths so as to match the changed size.

However, since the connecting plate and the fixed split head have large and complicated shapes that are integrated with each other, it is difficult to process the upstream-side flow paths with high accuracy afterwards. In addition, when changing the shape of the extrusion, it is also difficult to perform additional processing the downstream-side flow paths with high accuracy. In some cases, the additional processing itself becomes difficult, and it is necessary to remake the connecting plate and the fixed split head.

The present invention has an object to provide a head of a multi-layer extrusion device that can easily and accurately respond to changes in the size of extruders and changes in the extrusion shape.

The above object is accomplished by the features of claim <NUM>.

A head for multi-layer extrusion device has the features of claim <NUM>. It has a plurality of flow paths for separately guiding elastomeric materials from a plurality of extruders to a pre-former attachment unit, the head including: a main head to which the plurality of extruders is to be connected; an upper head part positioned above the main head; and a lower head part positioned below the main head, wherein the plurality of extruders includes a first extruder and a second extruder, and the main head, at least, is detachably divided into a first head part to which the first extruder is to be connected, a second head part to which the second extruder is to be connected, a third head part connected to the first head part on a downstream side of the first head part, and a fourth head part connected to the second head part on the downstream side of the second head part.

In the head for multi-layer extrusion device according to the present invention, it is preferable that the plurality of flow paths includes a first flow path to guide an elastomeric material provided from the first extruder and a second flow path to guide an elastomeric material provided from the second extruder, the first flow path includes a first upstream-side flow path passing through the first head part and a first downstream-side flow path extending along a boundary between the third head part and the upper head part, and the second flow path includes a second upstream-side flow path passing through the second head part and a second downstream-side flow path extending along a boundary between the fourth head part and the lower head part.

In the head for multi-layer extrusion device according to the present invention, it is preferable that the main head is configured to be capable of adding detachably a fifth head part to which a third extruder is to be connected.

In the head for multi-layer extrusion device according to the present invention, it is preferable that the main head is configured to be capable of adding detachably a six head part to which a fourth extruder is to be connected.

The head of a multi-layer extrusion device according to the present invention includes the main head to which the plurality of extruders including the first and second extruders is to be connected. The main head, at least, is detachably divided into the first head part to which the first extruder is to be connected, the second head part to which the second extruder is to be connected, the third head part connected to the first head part on a downstream side of the first head part, and the fourth head part connected to the second head part on the downstream side of the second head part. In such a head, the main head can be decomposed into at least four small parts including the first to fourth head parts, and the shape thereof can be simplified.

Thus, in this head, for example, when resizing the first extruder and/or the second extruder, the upstream-side flow paths can be processed separately with respect to the disassembled the first head part and/or the second head part, and thus workability and processing accuracy can be improved. Further, in this head, when changing the extruded shape of an extruded product, the downstream-side flow paths can be processed separately with respect to the disassembled the third head part and/or the fourth head part, and thus workability and processing accuracy can be improved.

Therefore, the head for multi-layer extrusion device according to the present invention can easily and accurately respond to changes in the extruders and changes in the extrusion shape.

An embodiment of the present invention will be explained below with reference to the accompanying drawings. <FIG> and <FIG> show the first embodiment of a head <NUM> for multi-layer extrusion device (hereinafter simply referred to as the "head <NUM>"). Further, <FIG> shows an example of an extruded product manufactured by the multi-layer extrusion device.

As illustrated in <FIG>, the head <NUM> according to the present embodiment includes a plurality of flow paths <NUM> which guides elastomeric materials G separately from a plurality of extruders <NUM> to a pre-former attachment unit <NUM>. A pre-former is indicated by the reference sign <NUM>.

The plurality of extruders <NUM> includes a first extruder <NUM> and a second extruder <NUM>. The plurality of extruders <NUM> according to the first embodiment consists of the first extruder <NUM> and the second extruder <NUM>. The multi-layer extrusion device according to the first embodiment forms a two-layer tread rubber Tg for tires (shown in <FIG>) using elastomeric materials G1 and G2 extruded from the first extruder <NUM> and the second extruder <NUM>, respectively.

In this embodiment, as the extruders <NUM>, so-called screw-type extruders in which a motor-driven screw shaft is housed in a cylinder is adopted. However, the extruders <NUM> are not limited to such an embodiment, and extruders having various known structures can be used.

The head <NUM> includes a main head <NUM> to which the extruders <NUM> are to be connected. The head <NUM> according to the first embodiment includes the main head <NUM>, an upper head part <NUM> positioned above the main head <NUM>, and a lower head part <NUM> positioned below the main head <NUM>.

The upper head part <NUM> and the lower head part <NUM> are movable type heads which are supported by the main head <NUM>. In the present embodiment, the upper head part <NUM> and the lower head part <NUM> are rotatably supported by pivot means <NUM> so that they can swing about fulcrum P up and down. The pivot means <NUM> include first pivot members 13A provided on the main head <NUM> side and second pivot members 13b provided on the upper head part <NUM> side and the lower head part <NUM> side. It is preferable that the first pivot members 13A is detachable from the main head <NUM>.

The main head <NUM> is dividable into, at least, a first head part <NUM>, a second head part <NUM>, a third head part <NUM> and a fourth head part <NUM>.

The first extruder <NUM> is connected to the back side of the first head part <NUM>. The second extruder <NUM> is connected to the back side of the second head part <NUM>. The first head part <NUM> and the second head part <NUM>, for example, are detachably coupled with each other via connecting means <NUM> such as bolts. The connecting means <NUM> is not limited to the bolts, but various structures can be adopted.

The third head part <NUM> is positioned a downstream side of the first head part <NUM>. The third head part <NUM> is detachably connected to the first head part <NUM> via the connecting means <NUM>, for example. The fourth head part <NUM> is positioned a downstream side of the second head part <NUM>. The fourth head part <NUM> is detachably connected to the second head part <NUM> using the connecting means <NUM>, for example. A bottom surface of the third head part <NUM> and an upper surface of the fourth head part <NUM> are butted with each other.

The plurality of flow paths <NUM> includes a first flow path <NUM> to guide an elastomeric material G1 provided from the first extruder <NUM> to the pre-former attachment unit <NUM> and a second flow path <NUM> to guide an elastomeric material G2 provided from the second extruder <NUM> to the pre-former attachment unit <NUM>.

As illustrated in <FIG>, the first flow path <NUM> includes a first upstream-side flow path 21U and a first downstream-side flow path <NUM> that is in communication with the first upstream-side flow path 21U. The first upstream-side flow path 21U, for example, has a circular cross-section and extends to penetrate the first head part <NUM> in a back-and-forth direction. The size of the first upstream-side flow path 21U may be set according to the size of the first extruder <NUM>. Specifically, the diameter D1 of the upstream end of the first upstream-side flow path 21U is set according to the diameter of the extrusion port (not shown) of the first extruder <NUM>. The diameter D1 is preferably set substantially equal to the diameter of the extrusion port. In this embodiment, the first upstream-side flow path 21U has a parallel hole with a constant diameter, but the first upstream-side flow path 21U may be a tapered hole whose diameter decreases toward the downstream side.

The first downstream-side flow path <NUM> extends along a boundary S1 between the third head part <NUM> and the upper head part <NUM>. It is preferable that the shape of the upstream end of the first downstream-side flow path <NUM> has the same as the shape of the downstream end of the first upstream-side flow path 21U. Further, the shape of the first downstream-side flow path <NUM> is set according to the shape of the extruded product (the tread rubber Tg in this embodiment). The first downstream-side flow path <NUM> in this embodiment gradually increases the width of the flow path while gradually decreasing the height of the flow path toward the downstream side.

The second flow path <NUM> includes a second upstream-side flow path 22U and a second downstream-side flow path <NUM> that is in communication with the second upstream-side flow path 22U. The second upstream-side flow path 22U, for example, has a circular cross-section and extends to penetrate the second head part <NUM> in a back-and-forth direction. The size of the second upstream-side flow path 22U may be set according to the size of the second extruder <NUM>. Specifically, the diameter D2 of the upstream end of the second upstream-side flow path 22U is set according to the diameter of the extrusion port (not shown) of the second extruder <NUM>. The diameter D2 is preferably set substantially equal to the diameter of the extrusion port. In this embodiment, the second upstream-side flow path 22U has a parallel hole with a constant diameter, but the second upstream-side flow path 22U may be a tapered hole whose diameter decreases toward the downstream side.

The second downstream-side flow path <NUM> extends along a boundary S2 between the fourth head part <NUM> and the lower head part <NUM>. It is preferable that the shape of the upstream end of the second downstream-side flow path <NUM> has the same as the shape of the downstream end of the second upstream-side flow path 22U. Further, the shape of the second downstream-side flow path <NUM> is set according to the shape of the extruded product (the tread rubber Tg in this embodiment). The second downstream-side flow path <NUM> in this embodiment gradually increases the width of the flow path while gradually decreasing the height of the flow path toward the downstream side.

In such a head <NUM>, the main head <NUM> can be decomposed into at least the first head part <NUM> to the fourth head part <NUM>, simplifying the shape. Thus, in this head <NUM>, when resizing the extruders <NUM>, the first upstream-side flow path 21U and/or the second upstream-side flow path 22U can be processed separately with respect to the disassembled first head part <NUM> and/or second head part <NUM>, and workability and processing accuracy can be improved. Further, in this head <NUM>, when changing the shape (extruded shape) of an extruded product, the first downstream-side flow path <NUM> and/or the second downstream-side flow path <NUM> can be processed separately with respect to the disassembled third head part <NUM> and/or fourth head part <NUM>, and workability and processing accuracy can be improved.

Therefore, the head <NUM> can easily and accurately respond to changes in the extruders <NUM> and changes in the extrusion shape.

The head <NUM> receives a strong tensile/compressive stress due to the internal pressure. For this reason, it is preferable to position and connect the head parts using keys (not shown) having sufficient strength to prevent misalignment between the head parts. Note that dividing the head <NUM> into multiple head parts while avoiding the occurrence of rubber leakage can be carried out without problems due to improvements in the performance of processing machines.

<FIG> and <FIG> show the second embodiment of the head <NUM>. As illustrated in <FIG> and <FIG>, the plurality of extruders <NUM> according to the present embodiment includes the first extruder <NUM>, the second extruder <NUM>, a third extruder <NUM>, and a fourth extruder <NUM>.

Further, the main head <NUM> includes the first head part <NUM>, the second head part <NUM>, the third head part <NUM>, the fourth head part <NUM>, a fifth head part <NUM> to which the third extruder <NUM> is to be connected, and a sixth head part <NUM> to which the fourth extruder <NUM> is to be connected.

In this second embodiment, the fifth head part <NUM> and the sixth head part <NUM> are optionally added to the main head <NUM> of the first embodiment. Specifically, the fifth head part <NUM> is positioned above the first head part <NUM> of the first embodiment. The fifth head part <NUM> is detachably connected to the first head part <NUM> via the connecting means <NUM>, for example. In this case, the first pivot member 13A is replaced from the first head part <NUM> to the fifth head part <NUM>.

Further, the sixth head part <NUM> is positioned below the second head part <NUM> of the first embodiment. The sixth head part <NUM> is detachably connected to the second head part <NUM> via the connecting means <NUM>, for example. In this case, the first pivot member 13A is replaced from the second head part <NUM> to the sixth head part <NUM>.

Furthermore, the fifth head part <NUM> and the sixth head part <NUM> support an upper head part <NUM> and a lower head part <NUM>, respectively, via the pivot means <NUM>. The upper head part <NUM> and the lower head part <NUM> are different in shape from the upper head part <NUM> and the lower head part <NUM> of the first embodiment.

The plurality of flow paths <NUM> includes the first flow path <NUM> and the second flow path <NUM> of the first embodiment, a third flow path <NUM> to guide an elastomeric material G3 provided from the third extruder <NUM> to the pre-former attachment unit <NUM>, and a fourth flow path <NUM> to guide an elastomeric material G4 provided from the fourth extruder <NUM> to the pre-former attachment unit <NUM>.

As illustrated in <FIG>, the third flow path <NUM> includes a third upstream-side flow path 35U and a third downstream-side flow path <NUM> that is in communication with the third upstream-side flow path 35U. The third upstream-side flow path 35U, for example, has a circular cross-section and extends to penetrate the fifth head part <NUM> in the back-and-forth direction.

The third downstream-side flow path <NUM> passes through the upper head part <NUM>. In the present embodiment, the upper head part <NUM> is dividable into a first upper head part 24A on the below side and a second upper head part 24B on the upper side. In the second embodiment, the third downstream-side flow path <NUM> extends along a boundary S3 between the first upper head part 24A and the second upper head part 24B. The first upper head part 24A and the second upper head part 24B, for example, are detachably connected with each other via the connecting means <NUM> (not illustrated).

The fourth flow path <NUM> includes a fourth upstream-side flow path 36U and a fourth downstream-side flow path <NUM> that is in communication with the fourth upstream-side flow path 36U. The fourth upstream-side flow path 36U, for example, has a circular cross-section and extends to penetrate the sixth head part <NUM> in the back-and-forth direction.

The fourth downstream-side flow path <NUM> passes through the lower head part <NUM>. In the present embodiment, the lower head part <NUM> is dividable into a first lower head part 25A on the upper side and a second lower head part 25B on the below side. In the second embodiment, the fourth downstream-side flow path <NUM> extends along a boundary S4 between the first lower head part 25A and the second lower head part 25B. The first lower head part 25A and the second lower head part 25B, for example, are detachably connected with each other via the connecting means <NUM> (not illustrated).

Thus, the head <NUM> can detachably add the fifth head part <NUM> and/or the sixth head part <NUM>. For this reason, the head <NUM> can also accommodate further multi-layering of extruded products with minimal changes.

In such a head <NUM>, in addition to the fifth head part <NUM> and the sixth head part <NUM>, further additional head parts can be added.

Conventionally, heads of multi-layer extrusion devices were not considered for expandability and were exclusively for the required specification, so it was necessary to prepare a head for each required specification. On the other hand, the head <NUM> according to the present embodiment can also be used as follows.

The head <NUM> may be prepared as a divided structure that assumes expansion to <NUM> to <NUM> layers, for example. Then, for example, when forming a two or three-layer extruded product having predetermined required specifications, some head parts that meet the required specifications are selected from a plurality of types of head parts prepared in advance and then are assembled to form a main head <NUM>. As a result, main heads <NUM> have one or more common head parts, capable of reducing inventory thereof and contributing to cost reduction.

Claim 1:
A head (<NUM>) for multi-layer extrusion device having a plurality of flow paths (<NUM>) for separately guiding elastomeric materials (G) from a plurality of extruders (<NUM>) to a pre-former attachment unit (<NUM>), the head (<NUM>) comprising:
a main head (<NUM>) to which the plurality of extruders (<NUM>) is to be connected;
an upper head part (<NUM>) positioned above the main head (<NUM>); and
a lower head part (<NUM>) positioned below the main head (<NUM>), wherein
the plurality of extruders (<NUM>) comprises a first extruder (<NUM>) and a second extruder (<NUM>), characterized in that
the main head (<NUM>), at least, is detachably divided into a first head part (<NUM>) to which the first extruder (<NUM>) is to be connected, a second head part (<NUM>) to which the second extruder (<NUM>) is to be connected, a third head part (<NUM>) connected to the first head part (<NUM>) on a downstream side of the first head part (<NUM>), and a fourth head part (<NUM>) connected to the second head part (<NUM>) on the downstream side of the second head part (<NUM>), wherein a bottom surface of the third head part (<NUM>) and an upper surface of the fourth head part (<NUM>) are butted with each other.