| 摘要 |
926,440. Moulding ribbed plastic sheeting. PRITCHETT & GOLD & E.P.S. CO. Ltd. March 15, 1962 [March 27, 1961], No. 11029/61. Class 87(2). In apparatus for moulding ribbed plastic sheeting from thermoplastic powders, prior to sintering, and comprising a hopper 4 for delivering a continuous layer of powder 5 on a travelling belt 1 and a die 7, located above the belt and provided with slots 8 for forming ribs on the powder layer 5a, a plurality of separate unattached balls 12 is distributed in a spaced row across the belt in the path of the powder layer travelling to the slots in the die. Each ball is positioned by two series of pins 13 and 14 which respectively maintain a desired spacing between the balls and the die face and loosely locate the balls on lines passing midway between pairs of adjacent slots 8. Sufficient clearance is allowed between each ball and the pins 14 to enable the balls to rotate freely solely by contact with the belt and/or the powder thereon. The balls 12 serve to channel the powder towards the slots, |
