| 摘要 |
<p>1,125,950. Extruding. FIELDING & PLATT Ltd., and D. V. ROWLES. 8 Dec., 1965 [18 Dec., 1964], No. 51635/64. Heading B3P. An extruded electrically conductive product 24 is pulled out of an extrusion press by inducing electromagnetic forces into the product. The latter is preferably of aluminium, aluminium alloy or copper. Upon emerging from the extrusion die 25, the product passes between carbon covered guides 26 into an air gap 4 provided between electromagnetic coils 2, 3. The upper coil 3 is mounted for vertical movement along guides 9, 10 by hydraulic or pneumatic cylinders 15, 16. After extrusion the discard is severed, coil 3 is moved downwardly to close the air gap 4 and the coils are energized by 3-phase alternating current to induce a longitudinal force into the produce and extract it from the die. The force may be varied by adjusting the voltage across the coils and a single force or a series of short duration forces may be used. A transverse force may also be applied to the product, by an hydraulic or pneumatic cylinder, by a vibrating pad or by induction coils, to facilitate its removal. The product passes on to a powered run-out table from which it is removed by lift-off arms. In other embodiments the electromagnetic device may be mounted on a carriage arranged to travel along the run-out table, or the longitudinal force may be produced by a pair of D.C. energized electromagnets which co-operate with a water spray to form a dielectric carrying a high current normal to the magnetic field. A longitudinal force may be applied continuously during extrusion to exert a pull on the product as it emerges from a water or air quenching station.</p> |
