Patent ID: 7316442

Claim:
A detachment prevention device of a seat rail for a vehicle, the seat rail comprising: a lower rail fixed to a bottom surface of a vehicle body by a fixing means, an upper rail located above the lower rail and coupled thereto; bent portions formed at both sides of the lower rail and the upper rail, respectively, such that the lower rail is hooked to the upper rail by means of the bent portions; a bracket extended from a center of the upper rail to an upper portion thereof in order to fix a vehicle seat to the upper rail; and a buckle fixed to the bracket to fasten a seat belt, wherein the detachment prevention device allows an outer side wall of an outer portion of the lower rail to have a greater degree of deformation upon deformation of the seat rail caused by excessive inertial force in the event of a crash to the buckle and the seat rail in order to suppress deformation of the bent portions, thereby preventing the seat from being detached from the seat rail, and the fixing means of the detachment prevention device is positioned at a fixing position deviated from the center of the seat rail in a direction in which the inertial force is not applied.