Patent GB-191421723-A (GB)
Title: Improvements in Glass-working Machines and Process of Working Glass.
Inventor: GRAY JOHN
IPC: C03B9/29
Filed: 1914-10-29
Granted: 1915-11-29
Abstract: 21,723. Gray, J., [Empire Machine Co.]. Oct. 29. Blowing; shearing, cutting, and the like.- Relates to the production of thin hollow glass-ware, such as electric lamps, tumblers, and lamp chimneys, by pressing and blowing, and consists in allowing the surface of the pressed blank to reheat by conduction from the interior before the final blowing takes place. The machine comprises a single severing and pressing mechanism and a number of units each comprising a moulding and blowing mechanism which rotate independently about a common axis and are arrested in a predetermined position on approaching a preceding unit. Each unit is secured to a carrier 22, Fig. 2, the ends of which rotate on central tubular shafts 2, 4, the columns being connected by a cam-drum 3 A cross-head 9, which is moved vertically by an air cylinder 75, supports a glass receiver 10 above the path of each unit. A second air cylinder 11, which operates the pressing-plunger 81, is situated above the receiver 10, and a shearing- mechanism is arranged between them. Each carrier has a pawl which engages ratchet teeth 21B on a rotating wheel 21, but is disengaged when the carrier reaches the operative position or approaches the preceding carrier. The shearing-mechanism consists of two blades which are pivoted together and operated by an air cylinder 63, Fig. 12. In order to cushion the inward stroke of the plunger, a supplemental port 71 is provided which is covered by the valve 64 on the instroke, as shown, and traps a quantity of air to cushion the piston 60<A>. Each blowing- unit consists of a glass-working spindle 31, Fig. 13, which is rotatable about its longitudinal axis and also about an horizontal shaft 29, which is journaled in the carrier 22. The spindle consists of a tube which contains a spring-pressed plunger 93 and is surrounded by a spring-pressed follower ring 91 and a neck ring 98<E> made in two parts. The plunger 93 is pressed inwards against its spring 95 by an arm 99, so that its head 94 forms a cavity in the blank. A necker 100<A>, Fig. 13, is pivoted on each carrier 22. The moulds consist of two halves 52, Fig. 2, pivoted together and mounted on a shaft near the lower part of the carrier. After each article is blown, the moulds are opened and are lowered into a water tank 52<B> formed on the base of the machine. In use, a stream of glass fed into the receiver 10, either from a furnace or from a pontil, is cut by the shears 61, 61 A as shown in Fig. 27<B>. The lower blade 61<A> is blunt, the cutting-face being only slightly bevelled, and the effect is to throw the severed end to one side of the receiver, where it is worked into the mass of the blank and is less detrimental to the finished bulb. The plunger 81 is then forced downwards on to the glass and presses it, as shown in Fig. 27<C>, a valve 81<B> permitting the escape of air, and the follower ring 91<G> moving downwards to accommodate any excess of glass which is forced beneath the neck ring. The plunger is removed, and the crosshead 9 is lifted to raise the receiver out of contact with the spindle. A button of glass is thus left on the spindle, which is then rotated on its longitudinal axis. A puff of air is introduced to swell the blank slightly, the spindle at the same time being rotated to bring it into an horizontal position, as shown in Fig. 27F. The admission of air, however, is delayed for a sufficient time to permit the chilled surface of the blank to reheat by conduction from the still fluid interior, the carrier meanwhile being set into motion to give place beneath the receiver to another carrier. The period of reheating is stated to prevent optical streaks ' in the finished article. The spindle is again moved so that the blank is inverted and a carbon edge of the necker 100<A>, Fig. 27<G>, is pressed against the blank close beneath the neck ring to reduce its diameter at this point and to localize its elongation. The blank is allowed to elongate, and the mould is then raised and closed about it, a full supply of air being admitted to complete the final blowing. After removal of the mould, the article is released by separating the halves of the neck ring.