GB250664A - Improvements in mechanically operated glass feeding apparatus - Google Patents

Abstract

250,664. Rankin, C. H. Jan. 15, 1925. Delivering molten metal.-Relates to a feeder of the kind in which a plunger or sleeve is movable to and from a discharge orifice and an adjustable stop is provided to limit the extent of the movement. According to the invention, means are provided for periodically removing from and returning to the operative position one or more stops, so that it is possible to delivera succession of " gobs " or mould charges of different weights. Means are also provided for varying the cross-sectional area of the discharge orifice, and for controlling the level of the glass around the reciprocating plunger. Varying the plunger stroke. The feeder comprises a forehearth having at its front end a well 1, Figs. 1 and 4, in the floor of which is the discharge orifice 2. A reciprocating plunger 3 controls the formation of the " gobs " of glass discharged through the outlet, and a sleeve 4, concentric with the plunger and capable of vertical adjustment, controls the flow of glass to the. orifice. The plunger 3 is carried by the piston rod of a cylinder 7, and is reciprocated by the admission of compressed air to the ends of the cylinder. The piston 6 has a tail-rod 10 which extends beyond the cylinder and terminates in a collar 11. The device for limiting the stroke of the piston consists of a small air cylinder 15, Fig. 1, arranged with its axis at right-angles to the cylinder 7 and carried by a bracket 12 secured to the cylinder. The position of the small cylinder 15 is adjustable vertically by means of a screw 19, and the piston rod 16 of this cylinder can be moved into or out of the path of the collar 11. The rod 16 thus acts as a stop for limiting the movement of the plunger 3, and by mounting a number of these small or stop cylinders at different heights, it is possible to control the stroke of the plunger 3, the rods 16 projecting either above or below the collar 11. Another form of stop consists of a rod 24 mounted in the end of the cylinder 7 and secured in its adjusted position by a screw 25. By mounting such a stop at each end of the cylinder 7, the maximum stroke of the plunger can be limited, lesser variations in the stroke being controlled by the cylinder 15. Compressed air for operating the pistons of the cylinder 7 is controlled by means of a timing-mechanism comprising cams 26 which operate distributing-valves 27, and the timing of the cams can be varied by mechanism such as that described in Specification 213,351. The speed at which the plunger 3 moves is controlled by cushion valves 35 in the pipe lines 22, 23 between the valve 27 and the ends of the cylinder 7. Each valve 35 consists of a spring- operated ball which admits air to, but prevents its escape from, one end of the cylinder. The escape of air is controlled by a by-pass valve the opening of which is determined by a wedgeshaped member operated by a small air cylinder. The regulation of the escape of the air controls the speed of the piston 6 and therefore of the plunger 3. The sleeve 4 may be adjusted vertically, in order to vary its distance above the floor of the well 1, by means of a worm-wheel 51 turned by a handwheel 54. Alternatively, the sleeve may be moved by an air cylinder 58 the movements of its piston being controlled in the same way as that of the piston 6. Varying the size of the discharge orifice. The outlet 2 may be expanded or contracted by means of two plates 70, Figs. 4 and 8, having opposed semi-circular edges, which slide over one another beneath the orifice. The separation of the plates is controlled by an air cylinder 63 the piston rod of which is connected to a cross-head 65 that operates levers 68 pivoted to the plates 70. The movement of the plates may be co-ordinated with that of the plunger 3. Feeding glass to the plunger. For controlling the level of the glass in the well 1, a paddleshaped impeller 73, Fig. 4, is used to propel the glass along the forehearth 71 over a wall 72 into the well 1, in the manner described in Specification 105,672. The paddle is reciprocated horizontally by an air cylinder 78 and vertically by another cylinder 75. The stroke of the pistons of these cylinders is varied in the same way as that of the piston 6, so that the path of the paddle can be varied in order to regulate the amount of glass fed to the plunger.