| 摘要 |
The nipple holder (15) of the cross-head has an axial hole (25) formed therethrough for passing the elongated article through the extrusion die 51, to receive a layer of a molten plastic material supplied from an inlet (17) from an extruder (4) of the cross head to be by a passage which includes a set of grooves formed in the nipple holder, including: a first groove (27) communicating from the inlet (17) toward the proximal end of the nipple holder; two second grooves (33) communicated to the first groove by branch grooves (29) and extending toward the distal end of the nipple holder; two sets of third grooves (35) extending toward the distal end of the nipple holder, each set from a corresponding second groove; and an annular nipple groove (39) communicating the sets of the third grooves to nipple. A further layer, of a second material, from a second extruder, may be extruded around the material delivered around the nipple holder (15), via a similar set of grooves formed in a guide provided around the nipple holder. <IMAGE>
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