Patent GB-325167-A (GB)
Title: Skimmer control means for glass blowing machines
IPC: C03B5/187
Filed: 1929-04-25
Abstract: 325,167. Bullman Machine Co., Ltd. Jan. 22,1929, [Convention date]. Gathering.-Relates to a rotary glassblowing machine of the kind in which charges of molten glass are sucked into the parison moulds from a non-rotating forehearth, and a skimmer precedes each parison mould to clear the surface of the glass before a charge is drawn into the mould. According to the invention, a guide member controls the movement of each skimmer in such a manner that the skimmer assumes different vertical positions during its passage through the forehearth. Means are also provided for enabling the skimmer to push surface glass out of the forehearth into the furnace. The parison moulds are carried by a rotary frame and are dipped in turn into an open forehearth 3, Fig. 3, which communicates with the interior of a tank furnace 1 by way of an opening 2. Each mould is preceded by a skimmer 5 which is of angular form and is' secured to the lower end of a stem 7 that forms one side of a jointed parallelogram, the other sides being formed by a lever 12 and links 16, 18. The lever 12 is pivoted at 13 to the machine frame, and has an arm 14 which is' acted on by a spring 15 in such a manner that the lever tends to swing upwards, and a roller 10 on the end of the lever is kept in contact with the underside of a guide rail 11 mounted above the forehearth. The link 18 is connected by a rod 20 with an arm 22 on a vertical shaft 26, and a spring 23 forces the link towards the centre of the machine. An arm 29, secured to the lower end of the shaft 26, carries a roller 30 which makes contact with a fixed cam 31 as the machine rotates. The guide rail 11 is carried by two links 33, 34, Fig. 1, which can be raised or lowered bv means of rods 38, 42, respectively. These rods screw into handwheels, 40, 44 disposed in a yoke 41 which screws on to a shaft 47. Thus by turning the shaft 47, the guide 11 can be raised or lowered as a whole, and by turning the handwheels 40, 44 its inclination to the horizontal can be altered. The shaft 47 may be geared to a shaft which controls the vertical position of a parison mould in its passage through the forehearth, as described in Specification 315,388, so that the vertical position of the moulds and the skimmers are adjusted simultaneously. In use, the roller 11 engages the front edge 11<1> of the guide 11, and the skimmer 5 is lowered into the glass in the forehearth and is kept in the glass so long as the roller engages the guide. The inclination of the guide can be so adjusted that the skimmer rises gradually during its passage through the glass. The guide may also be formed with a hump 56 so that the skimmer is first dipped into the glass with a thrust that breaks through the relatively tough surface, of the glass. As the skimmer is about to rise out of the forehearth, the roller 30 engages the cam 31 and the skimmer is forced outwards to the position 5<1>, shown in dotted lines in Fig. 3. This movement forces the surface glass, which piles up in front of the skimmer, inwards through the opening 2 into the furnace to be reheated.