Patent GB-564702-A (GB)
Title: Improvements in and relating to electric lamp making apparatus
IPC: H01J19/46
Filed: 1943-01-14
Abstract: 564,702. Discharge lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Jan. 14, 1943, No. 704. Convention date, Jan. 14, 1942. [Class 39 (i)] A composite electrode for electric discharge .devices is formed by sealing a pair of leading-in wires 20 and 21 into a glass stem 22, forming the inner portions of the wires with opposed filamentary coils engaging hooks 35 and 36, clamping the coil 80 within the hooks, and shaping the free extensions 66 to provide anode elements extending closely adjacent to the coils 80 and in the general direction thereof. Apparatus for carrying out this process embodies a conveyer 23 similar to that described in Specification 390,802, [Group XVII], which carries valve stems,past stations A, B, &c. on a table 19. where the valve stems are automatically operated on as they pass. Some of the operations, however, may be performed manually. The automatic operations are initiated by linkages operated by cams on a main driving shaft, not shown. The bending of the leads takes place at the first station A where the leads 20 and 21 are first gripped by cam-operated jaws. A die is then advanced against the protruding portions and a cam-operated roller bends back the leads against the surface of the die. The stem is then advanced past station B which is provided with electrical contacts which are connected by the leads 20 and 21 in passing. If the leads are defective, the circuit is not completed and a signal passes to the apparatus at station C. The cathode coil 80 is attached at station C by the apparatus shown in Fig. 7. Cathodes 80 are provided in pockets in a strip 81 which is fed intermittently from a spool 83 between rollers 88 and 89 by a driving wheel 92 driven by a ratchet 97. A solenoid 221 in the circuit of the electrical contacts referred to in the previous paragraph trips the ratchet if the stem is defective and thus prevents a cathode coil being fed thereon, the new strip 81 is wound on a spool 84 and an optional resting strip is wound on spool 106. A pneumatic suction nozzle 119 raises a cathode 80 from the belt and together with the cathode is moved by a pneumatic cylinder 129 to carry the cathode to transfer mechanism 86. Jaws on this mechanism close on the coil 80 and the nozzle 119 then retreats. The mechanism 86 is then raised bodily by a pneumatic cylinder 185 and brought into the position shown in the drawing in which the coil 80 is brought within the hooks 35 of the leads 20 and 21. Clamping jaws and fingers operated by further pneumatic cylinders now close the hooks round the cathode coil. The stem is now advanced to the next station where it is tested by apparatus of the type described in Specification 446,382, [Group XXVIII], and then passes to a further station where further jaws and fingers bend the free portions 65 and 66 of the leads into positions parallel to and on opposite sides of cathode 80 to form auxiliary anodes. The stem 22 now passes to station G where it is provided with an electron missive coating. A fluid comprising barium and strontium in suspension in liquid cellulose is contained in a cup 261 and a dipper 262 moved up and down by a cam and linkage brings a portion of fluid into momentary contact with each cathode coil 80 as it passes. A carrier 277 now picks the stem 22 from carrier 23 and carries it along for a period while it dries. The stem is now brought into contact with contacts on an adjacent carrier 285 which passes a momentary current through cathode 80 to complete the drying. The machine operator is placed after this point and removes the completed amounts. Specification 390,807, [Group XI], also is referred to.