Patent GB-404449-A (GB)
Title: Improvements in and relating to methods of and apparatus for manufacturing electric lamps
IPC: H01J5/24
Filed: 1932-12-19
Abstract: 404,449. Making electric incandescent lamps. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Donovan, J. F. ; 1869, Chapman Avenue, East Cleveland, Ohio, and Kubach, W. L. ; Emporium, Pennsylvania, U.S.A.) Dec. 19, 1932, No. 36002. Convention date, Dec. 18, 1931. [Class 39 (ii).] A mount comprising a flanged stem tube is sealed into the bulb of an electric lamp or the like by inserting the mount 53, Fig. 6, through the open neck of the bulb 30 until the flange of the stem is within the bulb and, holding the mount in that position, fusing or softening that portion of the bulb neck extending beyond the flange, and then bending the fused portion over on the flange. The sealed portion is subsequently stretched by pulling the bulb while the stem is still held in the machine. The apparatus consists of an intermittently revolving turret 10, Fig. 1, provided around its periphery with a series of work-receiving heads into which a bulb is inserted at the loading position. Each receiving head comprises a collar 31, Fig. 3, at the upper edge of a sleeve 32 which is slidably mounted on a spindle 33, friction blocks 33<1> forced against the spindle by screws 34 being provided to hold the sleeve in place. The spindle 33 is mounted in a hollow shaft 36 and prevented from turning therein by a coupling bar connecting it to the corresponding spindle of an adjacent head. A circular passage 45 about the shaft 36 is connected through the hollow spindle 33 to a suction pipe 46 which is connected to the ports of a rotary valve 49, Fig. 1, controlling the suction which holds the bulbs 30 upon their holding heads. After receiving a bulb the head is indexed to the third position of rest, where the exhaust tube of the mount is inserted between jaws 57 disposed above the head. Preferably the mount is of the tipless type, comprising the stem tube 53 and exhaust tube 54. The jaws 57 are carried upon a bracket 65 which is slidably mounted on a vertical bracket 66, the rise and fall of bracket 65 relatively to the bulb being controlled by a roller 67 engaging within a guide in a stationary cam disc 69. During the movement of the head to position four the mount is lowered into the bulb, and at the same time a raised part 74 of the cam disc 69 engages a roller 75 at the end of a slide which causes a pair of jaws 60 to close upon the stem tube. Simultaneously a clutch is automatically operated to engage a gear wheel 103 with a gear 93<1> at the lower end of the shaft 36, producing rotation of a bracket 93 carrying burners 88, 89 which direct their flames upon the edge of the bulb neck. The flames continue to rotate and play upon the bulb until it is stepped to position eight, where their rotary movement is stopped by disengagement of their driving clutch, the softened neck of the bulb now being bent around the flange of the stem tube by co-operating jaws 124-126, Fig. 9, mounted on sliding plates which are operated by a rocking lever 127, Fig. 8 (not shown) to control the opening and closing of the jaws. The head is now moved on to the next position whereupon the clutch of the burner bracket is re-engaged and the revolving burners play upon the bulb neck to fuse it to the stem tube while the head is indexed into position thirteen, where the flames are extinguished and the burners take up the stationary position shown in Fig. 1. Here the seal is stretched or shaped by pulling down the bulb while the exhaust tube is still held by the head, the stretching device comprising a pair of jaws controlled by a lever 185 and mounted on a carriage 193 which can be pulled down against the pressure of springs 204 by means of a rod 200<1> actuated by a lever 206 controlled by a cam 207. The jaws are opened during the movement of the head into subsequent positions until, at the nineteenth position, the lamp is unloaded by an air jet which blows the lamp out into a chute after cutting off the vacuum from the holding-head.