Patent GB-773044-A (GB)
Title: Improved method of winding grid electrodes
Inventor: THWAITES GEORGE PERCY
IPC: H01J19/00
Filed: 1955-10-07
Abstract: 773,044. Making grids for electric discharge devices; coiling. STANDARD TELEPHONES & CABLES, Ltd. Oct. 7, 1955, No. 28618/55. Classes 83 (2) and 83 (4). A method of winding individual grid electrodes comprises the steps of locating at least two support-rods in each of a plurality of mandrels, fixing a lateral wire to a support rod in one of said mandrels, rotating said one mandrel about its longitudinal axis and moving it along the said axis during rotation in order to wind the lateral wire along the length of the supportrods located in it to wind a grid, fixing said lateral wire to the support rods upon which it is wound, fixing said lateral wire to a rod located in an adjacent one of said mandrels, and severing the lateral wire between said wound grid and the rod located in the adjacent mandrel. An indexing-plate 1 carries a series of mandrels 8 around through positions 7 to 2. Each mandrel carries a pair of support rods 10, 11, on which grid wire 17 is to be wound, the ends of the rods being tapered for insertion in the mandrel. The plate 1 turns anti-clockwise to bring the rods past a knife-edged wheel 16, which cuts a slot in the outer rod 10, to a position 3 where the wire 17 passes through said slot. A wheel 18 swages the rod to the wire as the mandrel leaves position 3, At position 2 the mandrel rotates about its axis and moves longitudinally thereof to wind the wire 17 onto the rods 10, 11, a wheel 20 cutting slots for the wire in the rods and a wheel 21 swaging the rods to secure the wire turns. When the grid has been wound the mandrel moves to position 7 and the trailing wire 17 is severed between the completed grid and a succeeding pair of support rods 10, 11 with the wire attached thereto. The completed grid may be ejected from position 7 or means may be provided at positions 7, 6, 5 to comb, heat treat and stretch the grid and to eject it. The mandrels may alternatively be arranged along a belt. A continuously-rotated plate 53 carries a plunger 55 lifted by a cam 57 on a stationary rim 49 once every revolution of the plate 53 to engage one of six holes 63 in the indexing plate 1 to turn the plate 1 one step, a spring plunger 58 in a fixed plate 33 entering the next hole 63 to lock the plate 1 in its new position. Mandrels 66 with holes 69, 70 for the support rods are formed on cut-away shafts 73 mounted in cut-away cylinders 44 formed on the indexing-plate 1. At five positions, from 7 to 3, the shafts 73 are prevented from rotating by the engagement of the ring 49 in the cut-away part of the shafts; at the position 2, the left-hand position in Fig. 2, a cut-out in the ring 49 allows the shaft 73 to rotate. At position 2 a rotating shaft 88 is lifted by a rotating cam 92 first to engage a clutch-plate 75 on the shaft 73 to rotate the shaft and then to move the rotating shaft axially to wind the grid, a segment on the plate 53 entering the cut-away part of the shaft to complete the last half-revolution thereof as the clutch disengages. The pitch of the grid may be varied along its length by suitably forming the cam 92. In an alternative arrangement the plate 1 may be still and other parts moved therearound. In a modification, Fig. 5 (a), two mandrels 105, 106 are rotatably mounted on a fixed plate 104 and wire 111 from a spool 112 is passed through a slot in a supportrod 110 in the mandrel 106 and fixed to a support-rod 107 in the mandrel 105. The mandrel 105 then rotates to wind the grid on rods 107, 108 and the wire 111 is then broken between the mandrels, the grid ejected from the mandrel 105, the mandrel 105 reloaded, the spool 112 moved to the other end of the plate 104, the mandrel 106 rotated half-a-turn clockwise and then rotated in the opposite direction to wind the grid. The wire may be welded to the support-rods. Grids having three, four or more rods may be wound.