| 摘要 |
661,556. Extruding rubber. PIRELLI SOC PER AZIONI. Dec. 19, 1949 [Jan. 14, 1949], No. 32547/49. Class 87(ii) An extrusion head for channel section products of non-uniform thickness has a tapering deflector 7 disposed in the throughway to deflect the flow of material to the narrower parts of the orifice 9 and restrict the flow towards the wider parts to cause the speed of extrusion to be the same at all parts of the orifice. As shown, the invention is applied to the extrusion of pneumatic tyre treads, the die plate 8, having an arcuate orifice 9. The guide surface for the extruded material is provided by an ogival member 7, fixed by bolts (not shown), to the die plate 8. The die plate and member 7 are adjustable by means of nuts 10 and are held against displacement by a screw-threaded securing ring 6 provided with a buttress 14. A heating fluid may be circulated in the cavities 3.
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