Patent GB-368302-A (GB)
Title: Improvements in the manufacture of bottles and other articles in glass and apparatus therefor
IPC: C03B9/16
Filed: 1930-12-01
Abstract: 368,302. Glass manufacture. SMITH, A. E., 7, Lorne Avenue, Kensington, near Sydney, Australia. Dec. 1, 1930, No. 36179. Convention date, Dec. 10, 1929. [Class 56.] Blowing. - A method of making a parison, in the manufacture of bottles or other glassware, consists in introducing a plunger into a charge of molten glass in a parison mould, from the direction of the bottom of the article to be produced, so as to displace or distribute the glass around the plunger to form side-wall portions of an open-bottomed parison. The charge of glass may be fed into the open end of an upturned parison mould 9, Fig. 1, and the plunger 14 inserted through the open end of the mould so as to displace the glass and force it upwards into the space between the plunger and the wall of the mould. After removal of the plunger, the mould is inverted and is covered with a bottom plate, and air is then forced through the neck end of the mould in the usual way to expand the glass in the mould to form the parison. The cavity formed by the plunger 14 disappears during the expansion of the glass, and a more even distribution of the glass in the walls of the finished bottle is obtained. The bottom end 10 of the parison mould is extended to form a funnel which facilitates the entry of the glass into the mould. The displacing-plunger 14 is tapered, and its shoulder portion is a cylinder which slides through and fits closely into the bottom lip 15 of the mould. The joint between the plunger and the mould comes within the area of the bottom of the mould, and any seam formed by it will not show on the sides or edge of the finished bottle. The plunger 14 is hollow and is cooled by means of air blown through a pipe 17 which extends into the cavity 16. The air escapes through a ring of holes 18 over the top of the mould. In the construction shown in Fig. 9, the plunger is bored longitudinally and contains a rod 50 which carries at its lower end a valve 52 that forms the head of the plunger. The rod is free to slide for a limited distance, its movement being limited by a nut 55. Air pressure is applied to the interior of the plunger as it descends into the glass, but the valve 52 closes when it strikes the glass. When the downward movement of the plunger is completed, the pressure of the air forces the valve 52 still further into the glass, and the air then escapes from behind the valve and passes up over the surface of the plunger. This air chills the wall of the cavity in the glass and facilitates the withdrawal of the plunger. The device may be embodied in a machine in which the parison moulds and the finishing moulds are carried by separate horizontal tables that rotate step by step in unison with one another. When a parison is transferred to a finishing mould, it stretches and the rate of stretching is controlled by means of bottom plugs which are forced upwards into the mould when it is stopped at one or more stations of the machine. The sagging bottom of the parison is pushed upwards by the plug, so that the thickness of the glass that forms the bottom of the bottle can be regulated.