Abstract: A magnetic coupling for a device, such as a cathode, which is received in a vacuum bulb of a tube which has shafts for mounting the tube for rotation on an axis, has an inner ferromagnetic part disposed in the vacuum bulb and connected to the device and an outer ferromagnetic part which is arranged outside of the vacuum bulb and aligned with the inner part. The outer part comprises a magnetic arrangement having a plurality of pole pieces to which the poles of a ferromagnetic yoke that forms the inner part are allocated.

Abstract: A height-adjustable support arm with a parallelogram linkage has a stationary first articulated head and a second articulated head which is movable relative thereto, the second articulated head having a support bar connected thereto for mounting a device such as a hanging lamp. In order to avoid gaps in the exterior portion of the second articulated head, the movable parts thereof are surrounded by a flexible covering mounted on a tubular parallelogram leg at one end and at the free end of the support bar at its other end. The exterior dimensions of the covering correspond substantially to the tubular parallelogram leg and the interior dimensions are selected such that the second articulated head can move freely therein within an adjustment range.