Eccentric grinder with a device for changing a grinding motion

Claim 1

In an eccentric grinder, comprising a housing; a motor-driven shaft; a grinding disc; a pure eccentric drive connected to said shaft for driving said disc in one mode of grinding; a further drive for driving said disc in another mode of grinding and including at least friction and toothed crowns positioned on said housing and at least friction and toothed crowns positioned on said grinding disc wherein said crowns positioned on said housing are forcibly rollable on said crowns positioned on said grinding disc and one of said crowns (20) positioned on said housing is concentrical with said drive shaft and one of said crowns (17) positioned on said grinding disc is eccentric to and rotatably supported on said drive shaft; and means for changing a grinding movement of said disc, the improvement comprising said means including an intermediate element (23) rigidly connected to said housing and having a recess (22); and a ring-shaped member (19), said grinding disc (9) carrying one of said crowns (17), and said ring-shaped member (19) also carrying one of said crowns (20) which is engageable with said one of said crowns (17) of said grinding disc, said ring-shaped member being easily releasable from and connectable to said housing by means of said recess, said ring-shaped member (19) carrying another at least friction and toothed crown (21), said one crown (20) and said another crown (21) being formed at two edges of said ring-shaped member (19), respectively, said grinding disc supporting a further at least friction and toothed crown (18), wherein said ring-shaped member (19) is insertable into said recess in one position in which said one crown (20) of said ring-shaped member is engageable with said one crown (17) of said grinding disc or in another position turned by 180°, in which said another crown (21) of said ring-shaped member is engageable with said further toothed crown (18) of said grinding disc.