System commonly used in domestic clocks. The driving weight and counterweight are hooked to the opposite ends of a single rope passing through the groove of a pulley typically fitted with spikes. The pulley is connected to the driving wheel by means of a saw-toothed wheel with a hook that enables them to turn together in the direction imparted by the driving weight. The mechanism enables the pulley alone to rotate in the opposite direction if the counterweight is pulled down. This raises the driving weight at the opposite end and thus winds the clock.