| 摘要 |
<p><PICT:0925657/IV(a)/1> <PICT:0925657/IV(a)/2> <PICT:0925657/IV(a)/3> Extrusion apparatus for tubular or flat ribbed sheeting comprises a pair of die-carrying members 1, 2 movable transversely to the direction of extrusion, contacting slideway surfaces 1a, an extrusion orifice 1b adjacent surfaces 1a remote from the material supply, and rib extruding orifices 1c opening into orifice 1b for extruding ribs integrally with the sheeting. For tubes either or both dies 1, 2 may be rotated or oscillated or for flat sheets either or both may have transverse reciprocation. The dies may be detachable and the taper of the slideway surfaces 1a be reversed so that extrusion pressure tends to keep them in contact. The orifice 1b may be in either or both members 1, 2 and may be fed by slots 1d. The extruded tube may be expanded by fluid pressure, cooled by a ring 14, flattened by rollers 15 and stored on rollers 16. Where only one die roller is rotated the rollers 15, 16 may revolve around the machine to counteract any tendency of the sheet to twist during extrusion. The extrusion may be slit into a sheet. Specifications 836,555 and 836,556 are referred to.</p> |
