| 摘要 |
824,955. Extrusion machines. STANDARD MACHINERY CO. Aug. 21, 1956, No. 25556/56. Class 87(2). In an extrusion apparatus for rubber or similar plastic materials, comprising a supply passage 46 leading tangentially into the side of a longitudinal cylindrical bore 22 of an extrusion cylinder 16, Fig. 2 (not shown), and a rotating screw 18 feeding material along said bore and away from said passage, the wall of the bore has a relief recess 66 which is longitudinally coextensive with the passage outlet and is of decreasing radial depth in the direction of screw rotation. This recess reduces the regurgitation of material from the bore to the passage 46, and in the form shown supplements the action in this way of a recessed filler block 44 which limits the passage 46 in a hopper 12. In a modification the recesses also of progressively decreasing radial depth longitudinally of the bore in the forward feed direction and the surface of the recess facing the screw may merge smoothly with the bore longitudinally as well as circumferentially to facilitate the application of material, absorbed by the recess on primary regurgitation, to the screw on secondary regurgitation. The above action may be further expedited by a plurality of such recesses around the bore and by providing circumferentially spaced longitudinal grooves in said recesses, Fig. 4 (not shown).
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