Patent GB-646643-A (GB)
Title: Rotatably mounted turrets and indexing mechanism therefor
IPC: H01J9/32
Filed: 1946-12-19
Abstract: 646,643. Making vacuum tubes &c. SYLVANIA ELECTRIC PRODUCTS. Inc. Dec. 19, 1946, No. 37425. Convention date, Dec. 19, 1945. [Class 39(ii)] A rotatably-mounted turret for assembling and sealing a plurality of terminal pins 1 in the glass end closure 2, Fig. 14, of an electronic tube, includes a wall portion having a plurality of projections therefrom, regularly spaced and equidistant from the axis of the turret and means for indexing the turret a distance equal to the spacing between two adjacent projections. A plurality of spindles 8, Fig. 17, are regularly spaced, adjacent the outer edge of the turret 7, and each is mounted to rotate independently about a vertical axis on radial ball bearings 9, 10, located in annular flanges 11, 12, extending outwardly from the edge of the turret 7. Each spindle 8 has a closure member 14 on which is seated the lower mould 15 of a pair of press members. An axiallymovable rod 19 extends through openings in the members 14, 15 and has a tapered point 20 for use in the moulding process. Apertures are provided in members 14, 15 for receiving the appropriate number of terminal pins 1. An outer sleeve 25 is secured to the spindle shaft 8 and carries a sprocket wheel 28 and a friction clutch 27. The clutch rotates with the spindle and carries a pawl 30 which, when engaged by a latch at any one of the operating stations of the turret, locks the spindle 8 against rotation, allowing free rotation of the sprocket wheel 28. The chain 46, driven from an electric motor, engages all the spindle sprockets 28 except for some of those between "A" and " B," Fig. 1. The turret is arranged to rotate intermittently to bring successive spindles to the operating stations. Upstanding from the bottom wall 151 of the turret 7 are a plurality of regularly spaced studs 163, there being one for each spindle 8, and each of which carries a roller 165. An indexing slide 173 and a turret locking slide 186 are provided (Fig. 5) together with an operating shaft 127, and associated cams. Anti-clockwise rotation of the shaft 127 moves a cam (not shown) which controls the movement of lever 182, and, by means of link 181 and lever 179 causes outward movement of the block 173 into engagement with one of the rollers 165. Rotation of the cam 148 moves the lever 192, which, through the link 200, moves the block 186 inwards, disengaging a roller 165. Rotation of the cam 147 throws the lever 169 into the position shown as 169a, thus turning the turret through a distance equal to that between two adjacent rollers 165. By the action of the respective cams the slide 186 then moves forward to lock with the next roller, the indexing slide 173 is disengaged from its roller and returns, with its associated lever 169 to engage the next roller and repeat the operation. Hydraulic cushioning means are provided to prevent jarring of the turret during this intermittent movement, which moves each spindle 8, Fig. 1, one step forwards each time. When a spindle 8 is at "A" a pin 1 is fed to each of the apertures 21 in the closure 14, 15 from hoppers 51. This spindle advances intermittently to " B." At intervening stops the spindle is not being rotated by chain 46 and a pre-heated glass disc is placed over pins 1 on to mould 15. At " B " a contact finger 59 determines the absence of a glass disc from the top of a spindle, and, if such is the case, operates mechanism for removing the pins from the mould 15. Between " B " and " C " the spindle advances intermittently, rotating continuously, the workpiece being heated by a number of burners, such as shown at 61. At " C " a stem 4 from a hopper 67 is placed on the wafer 2 to which it is fused, being pre-pressed by a member 73. At " E " the spindle is locked against rotation and a press 70 mates with the mould 15 and tapered end 20 of rod 19 to shape the glass as in Fig. 14 and seal it to the pins 1. At " F " fingers 75 clamp the stem 4 of the finished workpiece, and, by means of swinging arm 76 deposits it in a discharge chute. An atomizer 78 sprays the empty mould at " G " to prevent adherence of the glass in the next operation.