Ribbed plates serve as a connecting element between the threshold and the rail. The ribs on the plate serve as a lateral guide for the rail and as a fixing point. For this purpose, the head of the hook bolt is inserted into the dovetail-shaped recess between the ribs so that the shaft can be used to fasten the rail with the aid of a clamping plate (K superstructure) or a tension clamp (KS superstructure).
