Improvements in the supporting and connecting devices for electric lamps, according to which a tubular support is provided inside which a block of insulating material and a threaded metal bushing, fixed to it, are permanently housed, permanently connected to one of the terminals of the supply circuit through a fixing element fixed to said block and arranged to receive the threaded bushing constituting one of the poles of the corresponding electric filament lamp; a rotor of insulating material is placed inside the said block, whose movements can be controlled through a corresponding external maneuvering member; this rotor forms on its periphery four equal protrusions in the shape of a saw tooth, three of which are covered by a metallic sheet fixed to one of the faces thereof; permanently resting on these teeth three elastic tongues, respectively integral of an outer flange element and of the two contacts arranged to establish connection with the other two poles of the lamp; all in such a way that depending on the position adopted by the rotor the elastic tongue connected to the input terminal establishes connection with one or the other, with both or with none of the other two tabs, determining the closing or opening of the power supply circuits of the two filaments comprising the lamp. (Machine-translation by Google Translate, not legally binding)
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