| 摘要 |
An extrusion head for sheathing elongate objects such as cables has a housing with an elongate bore in which there is a hollow mandrel through which is passed the object to be sheathed. At the discharge end of the mandrel there is a forming tool made up of an annular forming tool part on the mandrel and a concentric forming tool part at the adjacent end of the bore of the housing. An extruder connected to the extrusion head housing forces sheathing material into the bore of the housing and out through the forming tool to form a sheath on the cable or other object as it is passed through the hollow mandrel. A rotor which is rotatable on the mandrel has a screw thread web of decreasing height for propelling sheathing material toward the forming tool. There are lubricated radial seals between the rotor, mandrel and housing. For applying a double layer sheath, there are two entrusion heads interconnected one behind another and supplied with sheathing material by two extruders. Alternatively, an extrusion head has a smaller hollow mandrel inside a larger hollow mandrel and a three part forming tool with one part on the discharge end of the smaller mandrel, a second part on the discharge end of the larger mandrel and a third part at the end of the bore in the housing. There are two extruders of which one feeds sheathing material to the space between the mandrels and the other feeds material to the bore in the housing.
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