Optimized locking system

An opening device for a vehicle comprising an opening part and a stationary part, said opening part being movable relative to said stationary part between a closed position and an open position, the opening device further comprising an accompanying device accompanying the movement of the opening part when said opening part moves toward the open position, said accompanying device comprising a first part secured to the opening part and a second part secured to the stationary part, said first part being movable relative to said second part with the movement of the opening part relative to the stationary part, wherein the accompanying device further comprises a safety blocking device arranged to block the movement of the first part relative to the second part when an inertial force applied to the opening part toward the open position is above a predetermined threshold force such that the first part prevents the movement of the opening part toward the open position when said inertial force is greater than said predetermined threshold force,

• wherein the accompanying device is formed by a winder, the first part comprising a moving body and a cable, said cable being fastened on the one hand to said moving body and on the other hand to the opening part, and the second part comprising a stationary body secured to the stationary part, said moving body being rotatable in or on said stationary body, the cable being wound around said moving body when said opening part is in the closed position and unwinding around the moving body when said opening part moves toward the open position.