Abstract: In combination with a spool upon which elongated stock such as ribbon, wire, thread etc. is to be wound and from which the elongated stock is to be unwound; an electromagnet with cooperating armature and a yoke; the device is to be selectively used as a brake and as a clutch. This is accomplished by a permanent air gap from 0.1 to 1.5 mm between the yoke and the armature to remain effective in the energized state. On application of a relatively high voltage to the electromagnet positive coupling obtains between the electromagnet and the armature and, therefore between a shaft connected to the electromagnet and the armature as thereafter being connected to the spool; for positive common rotation of these parts. Upon application of a lower voltage to the electromagnet, a brake force becomes effective between the electromagnet on one hand, plus armature and the spool subassembly on the other hand.

Abstract: An apparatus for color coding and dyeing or otherwise marking a light wave conductor optical fiber includes a dyeing stage and a drying stage; the conductor is unreeled from a spool for passing through the stages, the marked conductor is taken up by another spool or the like, and a downstream drive is coupled to the conductor for moving it at a particular speed through the dyeing and drying stages. An upstream drive mechanism is also coupled to the conductor upstream from the dyeing stage for pulling the same from the supply spool, and includes a drive controlled towards the same speed as the downstream drive and a compensating roller to ensure sufficient tension in the conductor so that the upstream and downstream speeds are similar.