A device for driving a flexible strip provided with two rows of regularly spaced lateral perforations. This device includes a first slider to which is imparted a first reciprocating movement back and forth parallel to the direction of said strip, a second slider which moves with the first slider as far as the first reciprocating movement is concerned, but to which is also imparted a second reciprocating movement with respect to the first slider, a hinging plate mounted to pivot on the first slider and carrying claws each of which may cooperate with a perforation in one of the said lateral rows, and means enabling the said hinging plate to be moved towards or away from the second slider.