Abstract: The invention relates to a device for positioning and moving a surface treatment device along a wall. The device comprises a crane which can move along a top edge of the wall substantially in the horizontal direction. The crane comprises a crane jib which projects beyond the edge of the wall and along which a hoisting cable which can move up and down is guided. The surface treatment device is suspended from the hoisting cable in order to be moved up and down along the wall. The device also comprises a frame, preferably in the form of a gantry, which is suspended from the crane jib and can be moved with the crane along the wall substantially in the horizontal direction. The frame is designed to extend over an obstacle, for example a stiffener, extending in the longitudinal direction of the wall and to guide the hoisting cable over the obstacle.

Abstract: Grinding wheel for a floor grinding machine, comprising a metal wheel (1) with a first and a second flat surface. Diamond-containing grinding elements (11, 12) are arranged on the first flat surface. Grinding elements (11, 12), preferably diamond-containing, are also arranged on the second flat surface of the wheel (1).