Abstract: The eccentric grinder includes a housing, a fan wheel mounted rotatably in the housing and being rotatably driven in the housing during operation, an eccentric shaft mounted rotatably and eccentrically in the fan wheel, a grinding disk nonrotatably fixed in a central portion thereof with the eccentric shaft and an outer region of the grinding disk being arranged without connection to a remaining group of parts of the grinder and axially spaced therefrom; and at least one exchangeable reversible intermediate plate. Each of the intermediate plates can be mounted nonrotatably on the eccentric shaft between the grinding disk and the housing during operation in one of two positions. To cause a rotary motion of the grinding disk in addition to an eccentric motion one of the intermediate plates is provided with only one toothed or friction rim which is engaged in a fixed toothed or friction rim provided on the housing when the intermediate plate is installed in one of the two positions during operation.

Abstract: The eccentric grinder includes a housing, a griding disk on which a grinding paper is held, an eccentric shaft on which the grinding disk is nonrotatably mounted and a mechanism for changing a grinding movement of the grinding disk having at least one fixed friction or toothed rim. At least one exchangable reversible intermediate plate (17,37) is provided for the grinder attachable to the eccentric shaft and each having at least one other friction or toothed rim (21,22). In operation, one of the intermediate plates (17,37) is placed between the housing (6) and the grinding disk (24), which, when engaging the fixed friction or toothed rim (34,35) with one of its friction or toothed rims (21,22), causes a rotary motion of the grinding disk (24) in addition to an eccentric motion.

Abstract: An eccentric grinder includes a motor-driven shaft, an eccentric drive connected to the shaft to impart to a grinding disc one mode of grinding motion and a rolling drive including friction or toothed crowns on the grinding disc and the housing cooperating with each other to impart to the grinding disc another mode of grinding motion. The grinder is provided with a ring carrying two toothed crowns at the opposite edges thereof and releasably insertable into a recess formed in a ring-shaped element fixed to the housing of the grinder so that one mode of grinding can be easily changed to the other mode of grinding.