Locking device for a vehicle seat

This locking arrangement operates between the two sections of the seat back adjuster and has one cog element (11) fitted to one adjuster part and a second cog element fitted to the other part of the adjuster, and a tightener element (21), which, which in the locked position holds the two cog elements (11) together. A holder element (30), which, in the event of a crash, supports the first cog element (11) by means of its catcher faces (31,32,33,34).