Castor mounting bracket

The roller holder has at least one recess (B1, B2) in the form of an elongated hole along an axis and narrow part and a wide part. This enables the projecting fixing element (F1, F2) in the assembly plate (B) to be moved from a wide position (Pe1) to a narrow position (Pv1). The narrow part forms a stop for a stop element (T1) of the fixing element (F1, F2).