Abstract: An armchair (10) comprises a support frame (11, 12) to which a base seat (14), a back (16) and a footrest (26) are fastened, which elements are movable between a first and a second positions through power-driven movement means (21). The power-driven means (21) is suspended from said base seat (14) and movable therewith. Advantageously, the power-driven means is formed as a single power unit (21), having two independent driving shafts (22, 23). Still advantageously, the base seat (14) is pivotally mounted, at the front, to the support frame according to a first transverse axis (15); pivotally mounted to the rear of the base seat is the back (16) according to a second transverse axis (17) for rotation of the back itself; the back (16) has extensions (18) extending downwardly past said second axis (17) and having ends constrained to slide longitudinally of the armchair, so that upon rotation of the back about the second axis (17), the base seat rotates in the same way about the first axis (15).

Abstract: The dual power unit includes an elongate housing having mounted therein adjacent opposite ends thereof two power units, one of which is drivingly connected to the movable back of an armchair, and the other unit is connected to a movable footrest of an armchair. Each unit includes a pivotal shaft connected to the back or footrest of the armchair. Each such shaft is connected to the output shaft of an electronic motor reducer through a transmission-gear in the form of a screw extending transversely of the respective pivotal shaft. The screw is drivingly connected through a threaded slider which is in engagement with a pair of cam elements mounted on a respective pivotal shaft to impart pivotal movement thereto, and consquent movement to the portion of the armchair connected thereto.

Abstract: A method of detecting a condition requiring connection of a user apparatus with a feeder line comprises the steps of low-voltage power supplying the user apparatus through a detection impedance (17, 17a); detecting the waveform at the ends of the detection impedance; operating connection of the user apparatus with the feeder line when the waveform at the ends of the detection impedance is distorted in a manner that has been pre-established to be caused by actuation of a command in the user apparatus and requiring full powering of same. A device in accordance with the method comprises an analysis circuit (19, 37) detecting (by comparison with sample waveforms stored in a memory (20), for example) distortion of the waveform at the ends of the impedance (17, 17a) and consequently operating powering of the user apparatus.