Patent GB-190406040-A (GB)
Title: Improvements in Electric Arc Lamps
Inventor: LEVIS HOWARD COPPUCK
Filed: 1904-03-11
Granted: 1905-02-16
Abstract: 6040. Levis, H. C., [General Electric Co.]. March 11. Arc lamps, clutch. I n combination with a negative electrode formed of, or containing, materials which give a flaming arc, anon- consuming positive electrode is arranged to be moved transversely by the regulating-mechanism when the arc is struck, so that the arc is formed at one part and maintained from another part of the electrode. A fixed scraping-device may be provided, to keep the positive electrode free from condensed fumes. The arc is formed within the lower end of a central tube, which serves at once as chimney and lamp-frame. This tube is in three sections, 3, 11, 12, to the ends of which a cap 1, hood 6, and platform plate 10 are connected. An insulating-disc is placed between the flange 13 of the tube 12 and the platform plate 10, and the three parts are secured together by screws and nuts 15 insulated from the plate 10. The positive electrode 21 is a nearly semicircular bar of copper or like material, having its ends clamped between bow-shaped pieces 22 which embrace the central tube 12 and are pivoted to it. These are connected by a link 24 and rod 25, passing through an insulated bushing in the platform plate 10, to the U-shaped core 26 of solenoids 28. To the core is also attached the cylinder 31 of a dash-pot, which is constructed to damp only the upward movements of the core. The piston of the dash-pot is attached to the platform plate 10. The holder of the lower electrode 40 is carried by an arm projecting from a tube 38, which slides on a rod 37, and is prevented from rotating by a slotted arm 41 engaging a rod 34. The rods 34, 37 depend from a bracket 33, and the former is also attached to a disc 35 insulated from the platform plate 10. The pawl of the clutch 46 is adapted to grip the tube 38 when moved upwards, and is forked to embrace the shank of the dash-pot cylinder 31. A second similarly-acting clutch 50 has its pawl 51 attached to a spring 52 depending from the bracket 33. A fixed arm 53 serves to engage the clutch sleeve 46 and clutch pawl 51, and release the tube from either clutch. The tube 38 can be released from both clutches, when the lamp is to be trimmed, by pushing upwards a flanged sleeve 57 which slides on the tube. The lamp is provided with an electromagnet 60, a resistance coil 69, Fig. 4, and a fine-wound electromagnet 70. When the current is switched on, it passes through the solenoids 28, contacts 65, 66, and resistance 69. The core 26 of the solenoids 28 is thus raised, rocking the upper electrode 21 and raising the lower electrode 40 towards it. At the end of this movement, the clutch 50 is arrested by the arm 53, and the tube 38 slides through it, if the initial distance between the electrodes is great enough. When the electrodes touch, current flows through a conductor 89, the electrodes 40, 21, a conductor 92 representing the tube 12, Fig. 1, a screw 15, an electromagnet 60, and a conductor 90. The pivoted armature 61 of the electromagnet 60 rocks and separates the contacts 65, 66, thus putting the fine-wound electromagnet 70 into circuit with the solenoids 28 and resistance 69. The solenoids 28 being de-energized, the core 26 falls again, rocking the upper electrode 21, and allowing the tube 38 and lower electrode 40 to descend till the clutch 50 meets the disc 35. When the length and voltage of the arc incease by a certain amount, the electromagnet 70 raises its armature and closes a shunt circuit to the electromagnet 60 through a conductor 102, contacts 75, 76, and conductor 101. The armature 61 springs back and re-closes the circuit through the resistance 69 and solenoids 28, and the action of raising the lower electrode is repeated. A casing 77 is attached by screws to the hood 6, and surrounds the platform plate 10. Perforations 79 in the casing are sheltered by a hood 80. Another hood 81 carries the globe 83 by means of screws 82. The globe is partly closed by a bottom plate 84, air passing in through an aperture in the bottom plate, or between the edges of the globe and the plate 84 or hood 81. The fumes from the arc pass out from the central tube through perforations 4 in a boss 2 into which the tube 3 screws. The section 11 of the central tube is surrounded by insulating-material. The upper electrode 21 may be pivoted eccentrically, so as to assist in increasing the distance between it and the lower electrode during the striking of the arc.