| 摘要 |
<p>1,208,501. Adjustable extrusion die heads. CONDUCO A.G. 1 Jan., 1968 [30 Dec., 1966], No. 177/68. Heading B5A. During the extrusion of plastics tubing, in particular when associated with blow-moulding operations, nozzle end 40a, Fig. 3, of die head 35 is adjusted laterally with respect to mandrel 17 by the movement in the same direction of a pair of rods 42a, 42b, or by the movement of a second pair of such rods (not shown) in the same plane and at right angles to the first pair. Normally such adjustments of nozzle end 40a are'made to ensure the issuance of uniform thickness extrudate from orifice 46. As shown, rods 42a, 42b are moved by simultaneous rotation of spindle nuts 29a, 29b, interconnected by chain 33, with consequential movement of spindles 37a, 37b upwards and downwards, respectively, as determined by threading 38a, 38b, and similar axial movement of wedges 39a, 39b connected to the spindles. The second pair of rods is moved on rotation of spindle nuts 30a, 30b, Fig. 4. In the embodiment of Figs. 5, 6 (not shown), manual adjustment tool 45 is replaced by a pair of reversible electric motors (48a, 48b). A modification of this embodiment, Figs. 11, 12 (not shown), employs a single motor (96), electrically, hydraulically or pneumatically operated, which drives sprockets (99, 100) by means of chain (98). Sprockets (99, 100) are respectively connected to sprockets (125a, 126a) by chains (133, 132) and a clutch mechanism (103, 105, 107), Fig. 11 (not shown), driven by an hydraulic or pneumatic double-acting servomotor (115) brings either spindles (128, 128a) or (129, 129a) into rotation depending as clutch lever (107) is rotated about pivot (106) to bring clutch member (103) into engagement with spindle nut (123) or clutch member (105) into engagement with spindle nut (124). In the embodiment of Figs. 7, 8 (not shown), rods (64) are connected to the pistons (63) of two pairs of double-acting hydraulic cylinders (58a, 58b) and (59a, 59b). As before, the nozzle end is moved by movement in the same direction of one or other of the rod pairs. In a further modification, Fig. 9, 10 (not shown), the chain and sprocket arrangement 33, 34 &c. of Figs. 3 and 4 is replaced by gears (81a, 81b, 82a, 82b) or gear segments (87). Also the sprockets (97, 99, 100), Figs. 11, 12 (not shown), may be replaced by gears. In a final embodiment, Figs. 13, 14 (not shown), a multiplex die head comprises nozzle ends (140a, 140b, 140c &c.), and a single motor (137) drives gears (152, 152a, 152b &c.) to rotate, as required, clutches (150). Each clutch (150) may be brought by coaxial movement into engagement with a gear (153) to rotate one spindle pair or a gear (154) to rotate the other spindle pair. To further regulate the material flow, an axially reciprocable sleeve (79), Fig. 7 (not shown), may be incorporated in the die head. A nut (134), Fig. 11 (not shown), is rotatable on mandrel support (135) to move such a sleeve.</p> |
