Patent GB-152411-A (GB)
Title: Improvements in or relating to flaming arc lamps
IPC: H05B31/00
Filed: 1919-07-11
Abstract: 152,411. Jackson, P. R., (Sperry Gyroscope Co.). July 11, 1919. Arc lamps.-Means for intermittently rotating an electrode in one direction also feeds the electrode so as to maintain its arcing face in a substantially constant position. An auxiliary electrode may be arranged so as to receive current when the main electrode burns back too far, this current causing the feed to take place or to be accelerated. The positive electrode 4, Fig. 6, may pass through the upper bent end of a standard 2, in which is mounted a clutch device, comprising a sleeve 10 guided by a bracket 11 and having an enlargement 15 arranged to allow a slight axial movement as well as rotation. In a recess of the sleeve is pivoted a lever 18, Fig. 5, having an eccentric clamping-surface 23 and pivoted to a lever 20. This has a pin-and-slot connexion 21 to the sleeve and is attached by a rod 22 to a crank arm 33 on a shaft which is oscillated by crank and worm gear and an electric motor within the control box. In a modified form of clutch, the clamp lever 18, instead of being pivoted to the lever 20, carries a roller which works in a notch in the lever 20. Other forms of clutch are illustrated in Figs. 12 and 13. In Fig. 12, two curved jaws 105<a>, 110<a> are shown linked to crank pins on wheels 154<a>, 155<a> gearing together. One crank pin leads the other so that during upward motion of the pins the parts 105<a>, 110<a> are moved away from each other, but during downward motion of the pins the parts are forced towards each other. A spring connexion may be provided in one link. Fig. 13 shows two jaws 105<a>, 110<a> pivoted to a lever 113<a> attached to a reciprocating link 160<a>; a rod 162<a> passing through a shoulder 163<a> on the link and pivoted to the lever 113<a> is acted on by a spring 165<a>. On the sleeve 15, Fig. 5, is a stud 45 moving in a curved guide 46, Figs. 5 and 6, which can be tilted on a pivot 48 by means of an arm 49, link 50, and armature of an electro-magnet 52. Preferably, the guide is normally slightly inclined so as to produce a slow feed of the carbon. In a modification, the guide 46 has an arm carrying a segment in gear with a worm on a shaft which passes through the casing and carries a worm wheel; a worm gearing therewith can be rotated by hand or shifted axially by an electro-magnet. In either case the electro-magnet is connected to the auxiliary electrode. To prevent retrograde movement of the electrode, it is engaged by conductive brushes, which may be carried by arms 24, 25, Fig. 6, swivelling in brackets 11, 27 and drawn together by a spring 26. In a modification, a brush 28 is attached to a stem surrounded by a spring 31. Fig. 11 shows another arrangement for forcing the brushes inwards by links 20a and levers 18<a>. The brushes have curved edges to facilitate insertion of carbons. The auxiliary electrode 55, Fig. 6, may be attached to an insulated plate 140. As shown, it is attached to a shield 142 which forms with the plate a dead-air space around the upper electrode, preventing premature combustion. In a further modification, the shield and plate are integral and are connected by a tube around the carbon, the intermediate space having water circulated through it for cooling. The auxiliary electrode may form an arc about the main electrode to allow for wandering of the arm, which is deflected towards the auxiliary electrode by the current flowing in the pillar 2. The lamp is useful in projectors and for photography.