of the units is divided into two jaws 34 36 designed semicircular in shape the jaws 34 36 are supported in a joint shell 74 integral with the housing 10 in a fashion that allows them to pivot around a pivot axis 32 on the side opposite from the pivot axis 32 the jaws 34 36 are joined via a switching device 28 fig2 on the side closest to the switching device 28 a first projection 50 extending in the radial direction is integrally molded on jaw 36 and a second projection 52 extending in the radial direction is integrally molded on jaw 34 fig2 an external side of the first projection 50 has an active connection with an eccentric 54 of the switching device 28 while an external side of the second projection 52 bears against the housing 10 a compression loaded helical compression spring 30 bears with its ends against the opposing internal sides of projections 50 52 and loads the braking means 22 in its opening direction the eccentric 54 is joined via a screw 56 with a lever 58 of the switching device 28 fig2 torque acting between the rubber belt 20 and the braking means 22 can be adjusted on the braking means 22 by an operator via the lever 58 and the eccentric 54 of the switching device 28 if the disk type sander is.