The invention concerns a transverse winding mechanism for blinds designed to be mounted in a narrow recess defining a window frame in a building, which comprises a front crank exit for winding up the blind. The specific configuration of said winding mechanism enables interference between the cable and the conical gearing teeth to be avoided by separating the latter from the space designed to receive the cable when it is being wound. Said winding mechanism may have various configurations and further comprises a projecting element arranged in the inner region of the take-up reel which enables the cable to be fixed without having to provide through orifices of the axis of the reel at its upper wing.