Patent GB-534586-A (GB)
Title: Improvements in and relating to apparatus for sealing metal to glass
IPC: H01J5/42
Filed: 1940-03-18
Abstract: 534,586. Uniting metal to vitreous material by heat. BRITISH THOMSON-HOUSTON CO., Ltd. March 18, 1940, No. 5005. Convention date, March 16, 1939. [Class 36] A machine for automatically sealing metal terminal elements, and also an exhaust tube, to a preformed vitreous portion of an incandescent lamp, such as a glass cup of the character disclosed in Specification 515,091, [Group XI], comprises a turret 21 rotatable about a centre so as to bring a plurality of heads 20 into successive stations A, H, the cup and terminals being applied at A and/or B, the sealing thereof taking place at stations C, D, and the exhaust tube being applied and sealed at stations E. F. The metal skirt of the terminal element is, during heating, pressed into the softened cup, and subsequently the exhaust tube is pressed against the cup so as to have its end spread out. The cup 22, Fig. 2, has apertured bosses 33 over which are placed the skirts 31 of the terminals 29 the skirts being of the alloy disclosed in Specification 358,934, [Group II]. The leads 35 attached to the terminals 29 fit into guide tubes 34 which are kept raised-during the subsequent operation by a roller 38 which engages in a bracket 41 which is moved upwards so as to lift the roller into an upper track section, Fig. 6 (not shown), where it remains until the head reaches station H, whereupon it is lowered to the lower track by a bracket similar to 41. In passing to station C, the cup 22 is clamped by a pair of arms 61 which, when released by the roller 66 clearing a ramp 67, Fig. 1, are engaged by a spring 70 acting through linkage 71, 72 into operator position. where they remain until station H is reached. If the head does not carry a cup, damage to the guides 3A by the sealing flames is prevented by a shield 73 which is moved, towards the end of the movement of :shaft 63, to a position over the guides. Each of the stations has a pair of gas burners 85, Fig. 8, for each of the bosses 33 of the cup 22, the pairs being oppositely-rotatable after the manner of an egg-whisk by intermeshing gears 90 driven by gear 100 which is attached to a sprocket 101, all the sprockets 101 being driven by a chain 103. The chain-driving sprocket 108 is itself driven by a chain 120 from a shaft 122, Figs. 1, 7, which is driven by gearing 123 and a further chain 127 from a cam shaft 53, Fig. 7. The push rods 130, Fig. 8. which depress the terminals 29 into the softened bosses 33, are pressed down by the springs only during the rest period of the head, and are at other times held raised by a lever 135 which is pivoted at 136 and engages in a vertically-movable collar 138 on the centre 69. The collar 138 is operated from the cam shaft 53 by the cam 142 and system 145, 146, 147, 140. At station D, when the sealing is going on, a pointed rod 151 is raised into and rotated in the sealing aperture 152, Fig. 4, so as to dislodge obstructions. The rod is secured in arm 153 which is secured to, and guided by, a post 156 slideable in bracket 157, Fig. 2. Below arm 153 is a post 167 having tongues 166, 169, the latter normally engaging a slot in a positioning arm 170. A cam 165, Fig. 7, operates through arm 163, a lift rod 160 which raises the number 151 and also causes the tongue 166 to engage a slot 168 in an arm 161 which is then rotated by the cam 173 and arms 174, 176. In moving from D to E a roller 189 on an arm 190 Fig. 2, enters a cam 191, Fig. 7, which partially rotates a shaft 185, Fig. 2, to partially close a pair of jaws 181 adapted to receive the exhaust tube 200, Fig. 1, and position it over the exhaust aperture 152. When the head reaches E, the tube 200 is fed to the jaws by the means set out in Specification 449,166, [Group XXX], and the jaws are closed on to the tube by the lever 199, Fig. 7, operated by cam 207 through lever 205 and rod 206. At this point burners 209 are brought into position by a cam 221, Fig. 7, and lever 219 which operate the gearing 216 interconnecting the burner-carrying shafts 212, 214. The burners at station F are operated through rod 227 from the same cam 221, at which station the jaws 181 are lowered to bring the tube 200, against the cup 22. This downward movement is produced by lowering the column 188 against the action of spring 194 by engaging a roller 242 on a lever 228, Fig. 2, by means of a screw 243 on a claw 231, Figs. 1, 7, which is pivoted to pin 232 and operated from a cam 236 through a lever 235, shaft 237, and lever 238. At the same time, the rod 151 is again raised and rotated in the aperture 152, in this instance by a push rod 244 and arm 252 similar to 160,161, respectively, and operated by cams 247, 256, Fig. 7. When the jaws 181 are lowered by the descent of column 188, a latch 259 is rotated by spring 261 so as to come under, and be slightly spaced from, a fixed stop 260, the arrangement being that, when the spring 194 tends to return the jaws 181, the tube is stretched slightly and worked at its point of attachment, so making a more satisfactory seal. The jaws are then allowed to open by the roller 189 engaging a cam 271, Fig. 1, and are allowed to rise again by the release of latch 259 by cam 272, Fig. 2. Modifications are described in which the machine is adapted to seal a cup that is deeper and carries a neck portion closed by a relatively heavy end wall to which the terminals and exhaust tube are sealed, Figs. 11, 12 (not shown), and in which a shallower cup such as described in Specification 471,301 can be so treated, pressure between the cup and terminals being obtained in this form by raising the cup support instead of by lowering push rods such as 130.