The transition from this age-old handblown art to automatic machine methods was quite sudden. About 1905 MICHAEL J. OWENS, a glass-blower, had developed a successful and fully automatic machine for blowing bottles (Fig. 2). It could produce more than 30,000 bottles every 24 hours as compared with the six or eight hundred which a skilled handblower could turn out in an exhausting day's work.

For the common varieties of glass containers the principal raw materials are sand, soda ash, and limestone, though broken glass, called CULLET, generally is added to the mixture. These materials are melted in a FURNACE or TANK (Fig. 3). The mixture of raw materials is fed into the hottest, or melting, portion of the furnace, flows slowly into a cooler section of the furnace, and thence by way of a channel to the place from which it will be fed to the bottle-making machine.

The Owens machine (see Fig. 2) employs the so-called SUCTION PROCESS. Molten glass flows from the cooler section of the tank into a shallow REVOLVING POT. Iron molds mounted on arms radiating from a central pillar revolve so that each mold, during a part of its revolution, passes over the revolving pot. At this point the mold lowers itself until the open end touches the pool of molten glass, sucks up a CHARGE of glass, rises and moves on. As it rises, a knife slides across the bottom of the mold, closing it and cutting the glass off from that in the pool. The upper part of the cavity in the mold contains a PLUG against which the charge has been forced, thus forming the opening which later becomes the neck of the bottle (Fig. 4). In this manner the charge of glass has been shaped into a preliminary form known as the PARISON, which roughly approximates the shape of the finished bottle. This mold, termed the PARISON MOLD, then divides and withdraws and another mold, called the FINISHING MOLD, comes into place around the parison or embryo bottle which is hanging by its lip or neck. Thereupon the parison is blown into its completed shape within the finishing mold (Fig. 5). At this point in its revolution the arm passes over a CONVEYOR on which the bottle is deposited. The parison mold then swings back into operating position, to dip into the pool of molten glass once more. The machine may consist of from six to sixteen arms depending upon the type of ware to be produced and the speed of operation desired.

FIGURE 2.-Owens bottle machine, a fully automatic machine successfully operated in 1905.

FIGURE 4.-Action of Owens machine in filling mold by suction from the revolving pot.

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Since 1917 the so-called GOB-FED PROCESs for the automatic production of glass containers has been used in competition with the Owens suction method. The gob-fed process requires a FOREHEARTH-a covered channel conducting the molten glass from the tank to the device which feeds the charge of glass to the molds. Equipment for the process consists essentially of two separate mechanisms: a FEEDER for introducing molten glass into the molds, and a FORMING MACHINE for shaping the bottle. Molten glass is fed from a hole or ORIFICE in the bottom of the forehearth by a mechanism which causes the molten glass to be extruded in gobs, or separate drops, with a shape roughly approximating that of the molds into which they will drop. In some types of feeders (Hartford "Single Feeder") a RECIPROCATING PLUNGER OF NEEDLE operates over the orifice to control the quantity and shape of the extruded gob. Just beneath the orifice is arranged a pair of SHEARS which is operated in timed relation to the movement of the plunger so that it cuts off the suspended gob at the desired point in the cycle (Figs. 6 and 7). In some types of plunger feeders the shape of the gob is controlled by adjustments in the operation and timing of the plunger and shears. In those types of feeders known as AIR FEEDERS (Stuckey, Shawkee, et al) control over the extrusion of glass from the orifice is obtained through the use of an alternate air pressure and vacuum effect rather than by a plunger.

The forming operations in the gob-fed process are similar to the same operations in the suction process, although there are many variations in the mechanics employed. In some machines (Lynch, O'Neill) the parison and finishing molds are mounted on separate revolving systems or tables with the parison being transferred from one set of revolving molds to the adjacent revolving set, by automatic means. This is the so-called Two TABLE MACHINE (Figs. 8 and 9). In another type of machine (Hartford) a row of parison molds is in fixed position on a rectangular table (Fig. 10). The molds receive gobs distributed to them in turn from the feeder chutes or DELIVERY TROUGHS. After the parisons have been formed in these molds by an initial blowing operation they are swung in an arc and deposited in the finishing molds located on the other side of the table. The final blowing operation is accomplished in the second set of molds and the finished bottle is placed upon a conveyor by means of an AUTOMATIC TAKE-OUT.