Patent GB-232960-A (GB)
Title: Improvements in and relating to automatic glass blowing machines
IPC: C03B23/07
Filed: 1925-04-22
Abstract: 232,960. British Thomson-Houston Co., Ltd., (Assignees of Brown, C. A., and Nielsen, A. C.). April 23, 1924, [Convention date]. Blowing.-An automatic machine of the kind described in Specification 14209/15, for making electric lamp bulbs and similar ware from glass tubing, comprises a carrier having vertical guides on which a head is free to slide, a device on the head for gripping one end of a glass tube, a device for centring the tube without supporting it, means for periodically lowering the head, and devices for heating and moulding the free end of the tube. General construction. Fig. 2 is an elevation of the upper part, and Fig. 3 an elevation of the lower part of the machine which comprises an intermittently rotated framework with eight heads 34 each of which carries two glass tubes. Thus there are sixteen tubes in the machine, and they are carried step by step to the various burners and finally to the moulds 102. The machine also comprises a table 11 for supporting the moulds, burners, &c., a central shaft 14 which is rotated continuously and times the different operations, and spiders 28, 32 which are joined to one another by columns 31 and form a frame that is rotated step-by-step about the shaft 14. Pairs of vertical bars 33 extend from one spider to the other and form guides on which the heads 34 slide. The moulds consist of two sections 101, 102 which slide in horizontal guide bars 105 supported on the table 11. The mould sections are opened and closed by a reciprocating rod 108 having a crosshead 109 which is connected to the sections by adjustable links 111. Supporting the glass tubes. Each head 34 has a pair of hollow spindles 35 which carry the glass tubes. A rubber ring 80 on each spindle can be contracted by a sideways movement of a handle 69. A tube is slipped over the ring and spindle, the handle is moved back to its mid position and the ring expands and grips the tube. Each head has a roller 66 that rests on a circular track 58. A number of these tracks are. adjustably secured to! a stationary hollow shaft 59, and each track is formed with a gap 67, Fig. 16, and an inclined guide 68. When the roller 66 reaches a gap, it slides down the guide on to the next lower track, thus lowering the head, and therefore the glass tube it carries, through a space which is equal to the length of tubing that is formed into a bulb. When a head has descended to the lowest track, an inward movement of the handle 69 withdraws the roller 66 from the track and allows the head to be raised to the top of the guides 33. The spindles and the tubes are rotated by a shaft 39 which passes through each head. Air for blowing the bulb is supplied through a flexible tube 136 connecting the head to a valve box 133 that regulates the distribution of the compressed air. The glass tubes are centred in relation to the burners and moulds by spring-actuated jaws 87, 88 mounted on the spider 28. The jaws guide and steady the tubes without preventing them from rotating or moving longitudinally. Operation. The different operations performed on the tubes are shown diagrammatically in Fig. 14. In passing from station G to station H, a head 34 descends and lowers the tubes. At station H burners 51 heat the tube above the bulb already formed, and the heating is continued at station A. At station B burners 52 heat the tube along the line on which the cut-off takes place, the cut being completed by burners 53 at station C. The lower end of the tube is fused and closed at station D by burners 54, and burners 55 at station E continue the heating over a larger area. At station F the final heating is given by burners 56 and the plastic ends of the tubes are blown in the moulds at station G. When necessary the heads are loaded with new tubes at station H. The tubes are rotated continuously while, they are being heated and blown.