| 摘要 |
353,770. Glass manufacture. MACBETH-EVANS GLASS CO., Charleroi, Pennsylvania, U.S.A.-(Assignees of Sloan, T. H. ; Bentleyville, Pennsylvania, U.S.A.) Sept. 26, 1930, No. 28869. Convention date, Sept. 28, 1929. [Class 56.] A method of forming a thinwalled glass article, such as an electric lamp bulb, consists in pressing a charge of molten glass to form a blank 1, Fig. 1, having a dome-shaped upper surface 10 surrounded by a chilled flange 11, and holding the blank horizontally by the chilled flange while the central portion sags downwardly through the flange as shown in Fig. 2. The blank is allowed to elongate, and the finished article is blown from the elongated blank. Apparatus for carrying out the method comprises a parison mould 2 and a vertically movable plunger 3, the mould being surrounded by chuck fingers 4 having inturned lips 5 between which and the mould the chilled flange 11 is formed on the blank. The plunger moves within a cup 6 which receives a charge of glass when the plunger is lowered. The face of the mould 2 is concave to provide the blank with a domed upper surface, while the top face of the plunger 3 is plane to form the blank with a flat lower surface. An opening 7 in the mould 2 allows air to be blown above the blank. In use, a blank 1 is formed by pressing, as shown in Fig. 1, the plunger and cup are removed, and the blank is allowed to sag downwards through its flange which is held by the chuck lips 5, as shown in Fig. 2. The blank is then allowed to elongate by gravity, assisted by air blown through the opening 7 in the mould. The blank continues to elongate, and may be rotated about its vertical axis if desired. Finally, the blank is enclosed in a, finishing mould and blowing is completed.
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