Abstract: A mounting device for bearings placed on shaft extensions consists of a lower support basin rigidly connected with the frame and of a lid, connected in a pivoting manner with same, provided with a lower lever forming the operating portion which, when the lid is in the open position, extends into or across the support basin far enough to pivot the lid into its closed position by lowering the bearing abutting against it and placed on the shaft extension; in which closed position the basin rests tightly against the bearing with its circular, curved inner side. For the sake of simplification, a single lid is provided in a pivoting manner with a locking lever, which has at its end a hook portion, which engages an abutment of the support basin. Furthermore, an arrangement is provided which automatically pivots the locking lever.