GB1099074A - Improvements in or relating to the manufacture of pinched foot-tube assemblies - Google Patents

Abstract

In a machine for making foot-tube assemblies of the kind comprising one or more lead-in wires and a glass exhaust tube sealed into a glass foot-tube, sets of components are placed on an endless horizontally moving conveyer with the axes of the foot-tubes horizontal and transverse to the direction of travel. The components of each set are then moved into the correct relative positions for the pinching operation and are <PICT:1099074/C1/1> <PICT:1099074/C1/2> carried by the conveyer at a steady speed first through heating means, which soften the glass in the region to be pinched, then through means which lift the lower heat-softened wall of the foot-tube to cause it to adhere to the softened exhaust tube, and then through the pinching means which consist of pinching dies arranged to close around the foot-tube and to travel along at the same steady speed to effect the pinching before separating to release the assembly. In the preferred embodiment an endless chain conveyer 3 carries a plurality of equally spaced support means 7 which are fed with the components of foot-tube assemblies as they pass two lead-in wire magazines 8 and 9, an exhaust tube magazine 10 and a foot-tube magazine 11. Each support means is mounted on a pair of rods 33, 34, Fig. 2, which connect the two roller chains 31, 32 of the conveyer, and consists of a bracket 41 fixed on the rod 33 and adapted to hold the foot-tube 54, and a bracket 49 slidable on the rods towards and away from the bracket 41. The lead-in wires 44 rest in grooves 42, 47 in the respective brackets and the exhaust tube 45 is supported in grooves 43, 48. When the support means has received a set of components a cam follower 51 on the bracket 49 engages a fixed cam (52, Fig. 5, not shown) which moves the bracket 49 towards the bracket 41 and advances the lead-in-wires 44 into the foot-tube 54 until the ends of the wires rest in grooves 63 in a further support bracket 62. A pair of pivotally connected comb blades 65 travel in synchronism with the conveyer and close about the wires to centralize and guide them as they are advanced into the grooves 63. A rod 57 having a centring pin 58 is slidably mounted in an upstanding portion 59 of the bracket 49, and when the lead-in wires have been advanced the rod is moved by a fixed cam (61, Fig. 5, not shown), to engage the centring pin in the end of the exhaust tube 45 and advance the exhaust tube into the foot-tube until it rests in a groove 64 in the bracket 62. A stainless steel pin 66 slidably mounted in the bracket 62 is then advanced into the other end of the exhaust tube to support the latter. The support means 7 now carries the components through gas burners 18 and past a pivoted lever 19 which lifts the softened lower wall of the foot-tube into contact with the exhaust tube. The pinching dies 27 are spaced around the periphery of a pair of wheels 22 which are driven in synchronism with the conveyer by a star wheel 25 engaging extentions 26 of the rods 34. As each foot-tube assembly passes between the wheels it is engaged on opposite sides by a pair of dies which form the pinch seal. The sealed assemblies may pass through an annealing stage 28 before leaving the conveyer at 30.