A device for locking and unlocking a leaf a closure system such as a door, window or the like includes, said device: - including: - a casing intended to equip said leaf or a sash-frame of the closure system; - a latch nut mounted in rotation with respect to said casing along an axis of rotation as well as along a determined stroke of rotation, and including driving means as well as receiving means for receiving a maneuvering organ; - a locking rod, on the one hand, mounted in translation with respect to said casing in a direction and along a determined stroke of translation, as well as between a locking position and an unlocking position and, on the other hand, including complementary driving means cooperating with the driving means of the latch nut, for driving said rod by said latch nut; - the driving means and the complementary driving means, which are shaped so as to adopt, on the one hand, an active cooperating position over only a portion of the stroke of rotation of the latch nut and, on the other hand, an inactive cooperation position over at least another portion of the stroke of rotation of the latch nut; - opposing means (5; 5') for opposing the translational movement of the rod with respect to the casing, in the inactive cooperation position between the driving means and the complementary driving means, said opposing means (5; 5') including two stops (50; 50'), which the rod includes; - wherein the opposing means further include two organs (51; 51'), which the latch nut includes, which are each designed to cooperate with one of these stops (50; 50') in the inactive cooperation position between the driving means and the complementary driving means, and which are axially and angularly offset along the axis of rotation of the latch nut. - including: - a casing intended to equip said leaf or a sash-frame of the closure system; - a latch nut mounted in rotation with respect to said casing along an axis of rotation as well as along a determined stroke of rotation, and including driving means as well as receiving means for receiving a maneuvering organ; - a locking rod, on the one hand, mounted in translation with respect to said casing in a direction and along a determined stroke of translation, as well as between a locking position and an unlocking position and, on the other hand, including complementary driving means cooperating with the driving means of the latch nut, for driving said rod by said latch nut; - the driving means and the complementary driving means, which are shaped so as to adopt, on the one hand, an active cooperating position over only a portion of the stroke of rotation of the latch nut and, on the other hand, an inactive cooperation position over at least another portion of the stroke of rotation of the latch nut; - opposing means (5; 5') for opposing the translational movement of the rod with respect to the casing, in the inactive cooperation position between the driving means and the complementary driving means, said opposing means (5; 5') including two stops (50; 50'), which the rod includes; - wherein the opposing means further include two organs (51; 51'), which the latch nut includes, which are each designed to cooperate with one of these stops (50; 50') in the inactive cooperation position between the driving means and the complementary driving means, and which are axially and angularly offset along the axis of rotation of the latch nut.