260,205. General Electric Co., Ltd., (Assignees of Patent-Treuhand-Ges. f³r Elektrische Gluhlampen). Feb. 6, 1926, [Convention date]. Filaments.-In a filament-spiralling machine of the kind in which a wire is coiled intermittently on a continuously moving mandrel wire by the action of a rotatable measuring-wheel placed in a rotary winding-head, the measuring-wheel is provided with one or more contacts or pieces of insulating material and is inserted in a relay circuit of which the relay, when the circuit is completed, closes a second circuit to effect the rotation of the winding-head. The mandrel wire- 3, Fig. 1, is fed forward from a coil 2 through a shaft 1 carrying a sleeve 4 which carries a bell shaped electromagnet 7 and a keyed belt-driven, pulley 5. The belt pulley and electromagnet carry insulated slip rings 6, 8 respectively. A disc 9 carrying the supply reel 13 for the coiling wire 14 is provided with a loose insulating ring 10 having slip rings 11, 12. A bracket 17 projecting from the disc 9 carries a measuring-wheel 19, the flanged periphery of which has an insert 21 of insulating material. The coiling wire 14 passes over a guide pulley 22, round the rim 23 of the measuring-wheel and finally over a guide pulley 16 mounted on an arm 15 to the mandrel wire 3. The rotation of the disc 9 is normally braked by a lever 25 actuated by a spring 26, but the braking lever may be withdrawn from the disc 9 by a relay 27 which forms part of a circuit (shown in dotted lines) including the slip ring 8, electromagnet 7, slip ring 6, and contact 32. The latter is controlled by a second relay 29 in a circuit (shown in continuous lines) including the slip ring 11, spring contact 24, wheel 19, disc 9, and shaft 1. In operation, when the parts are in the position shown in Fig. 1, the arm 24 rests on the insulating piece 21 and breaks the circuit of the relay 29. The contact 32 is thus also broken and the braking lever 25 holds the disc 9 stationary. The mandrel wire continues to move forward and thus rotates the measuring-wheel until the arm 24 passes off the strip 21, thus eriergizing the relays 29, 27 and the magnet 7. The brake is thus removed and the winding head rotates with the shaft 1 and winds a helical coil on the mandrel wire, the length of the coil being determined by the size of the measuring-wheel and the number of insulating pieces 21. The helically coiled portions are separated by straight lengths of wire which are formed when the disc 9 is stationary. To facilitate coiling, the wire being coiled is raised to incandescence by an electric circuit including the shaft 1, mandrel wire 3, the coiling wire, pulley 16, arm 15 and the ring 12. In a modification which permits the winding of longer coils, an additional relay 33, Fig. 2, in the circuit of the relay 29 operates through a lever 35 a ratchet wheel 37 which turns with a disc 38 having 'a number of insulating pieces 39. A contact 40 engaging this disc is connected by a wire 34 with the slip ring 6. In this form, when the circuit in the relay 33 is broken by the insulating piece 21, the relay 27 and magnet 7 are energized by current passing from the disc 38 through the wire 34. The winding-head thus continues to revolve until the disc 37 has been rotated by the pawl 36 so as to bring one of the strips 39, against the contact 40. When next the strip 21 arrives at the arm 24, the rotation of the winding-head will be interrupted and a straight piece of wire will be laid on the mandrel 3. until the pull of the wire causes the strip 21 to leave the arm 24. The length of the helical coil thus depends on the distance between the strips 39 which corresponds to several teeth of the ratchet wheel 37. In another modification the contacts 32 may be connected with the lever 35 and the relay 29 omitted.