| 摘要 |
328,365. Firestone Tyre & Rubber Co., Ltd., (Firestone Tire & Rubber Co.). Feb. 22, 1929. Extrusion machines.-A tubing machine head includes a core die or plug 17 having a maximum diameter greater than the diameter of the extension orifice and mounted with the maximum diameter exteriorly of the orifice to permit removal of the die without dismounting the head. The machine comprises a feed screw 11 rotatable within a cylindrical bore 12 and a head 13 formed with passages 14 for the circulation of steam or cooling water and an internal shoulder 15 on which seats a spider 16 supporting the core die 17 by a tubular mandrel 18. The nozzle 19 is retained in the head by a bushing 20 and has a tapered bore 21 continued in a ring die 22 secured in the nozzle by a bushing 23. The core die 17 is slidably mounted on the mandrel 18 with its maximum diameter outside of the ring die for ready removal without dismantling the die 22 or nozzle 19. A cap nut 24 threaded on the end of the mandrel enables the position of the core die to be adjusted for regulating the thickness of the tubing. The spider 16 comprises inner and outer rims 25, 26 connected by threes arms 27 having ducts 31 connected with a groove 28 in the outer rim 25 and opening into a central cavity 30. Compressed air, dusting powder, or other material is introduced into the interior of the tubing being formed, by feeding it to the spider through a conduit 29 whence it passes through the bore of the mandrel 18 to a spray nozzle formed by holes 32 in the cap nut 24. Set screws 33 adjustably locate the nozzle 19 with respect to the core die 17. The arms 27 are shaped to present minimum obstruction to the flow and are widened at the portions adjacent the central hub 26 to afford substantial support for the mandrel 18.
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