Abstract: A driving pulley mechanism comprises at least one driving pulley consisting of two parts which are provided each with one part of a cable groove having a relatively great capacity of output transmission and are pressed toward each other by pressing devices.Each pressing device comprises a spiral spring or consists of a single or multiple leaf spring and is coupled for rotation with the driving pulley parts, on both of which it rests directly or indirectly.The driving pulley may cooperate with another (identical or conventional) driving pulley which rotates at the same speed e.g. by means of two gears mounted on the peripheral edges of the driving pulleys.