Detachable coupling of a rotor cup and rotor shaft in an open-end spinning rotor

1. An open-end spinning rotor having a rotor shaft and a rotor cup, the rotor shaft being supported in a spinning-rotor bearing and the rotor shaft and the rotor cup being detachably connected via a coupling device for removal of the rotor cup while the rotor shaft remains supported in the spinning-rotor bearing, characterized in that the coupling device comprises:

a) a magnetic device comprised of a permanent magnet fixed to the rotor shaft by a receiving casing having a cylindrical bore that surrounds a corresponding guide attachment on the rotor cup for fixing the rotor shaft and the rotor cup axially with respect to one another solely by magnetic attraction therebetween during spinning operation, and

b) a mechanical rotational safety mechanism comprised of an interior polyhedral receiving area in the receiving casing and a mating exterior polyhedral surface on the rotor cup for fixing the rotor shaft and the rotor cup radially with respect to one another.

2. The open-end spinning rotor according to claim 1 , characterized in that said magnetic device comprises said permanent magnet fixed on the rotor shaft and said guide attachment is a ferromagnetic attachment on the rotor cup.

3. The open-end spinning rotor according to claim 2 , characterized in that said permanent magnet is received in said casing for connecting to said rotor shaft for unitary rotation therewith.

4. The open-end spinning rotor according to claim 3 , characterized in that the casing is fixed on the rotor shaft by a press fit.

5. An open-end spinning rotor having a rotor shaft and a rotor cup, the rotor shaft being supported in a spinning-rotor bearing and the rotor shaft and the rotor cup being detachably connected via a coupling device for removal of the rotor cup while the rotor shaft remains supported in the spinning-rotor bearing, characterized in that the coupling device comprises:

a) a magnetic device comprised of a receiving casing fixed to said rotor shaft having a cylindrical bore that surrounds a corresponding guide attachment on said rotor cup, one of said receiving casing and said guide attachment having a permanent magnet fixed thereto for fixing the rotor shaft and the rotor cup axially with respect to one another solely by magnetic attraction therebetween during spinning operation, and

b) a mechanical rotational safety mechanism comprised of an interior polyhedral receiving area in the receiving casing and a mating exterior polyhedral surface on the rotor cup for fixing the rotor shaft and the rotor cup radially with respect to one another.

6. The open-end spinning rotor according to claim 5 , characterized in that the other of said receiving casing and said guide attachment is ferromagnetic.

7. A rotor cup for use in an open-end spinning rotor having a rotor shaft supported in a spinning-rotor bearing with the rotor shaft and rotor cup being detachably connected by a coupling device that includes a magnetic device having a permanent magnet fixed to the rotor shaft, said coupling device including a cylindrical bore that includes an interior polyhedral receiving area, said rotor cup comprising a cup portion having an open outer end for receiving textile fibers and for drawing off spun yarn, a hollow interior, a conical wall diverging inwardly from said open outer end, a yarn forming groove at the base of said conical wall, and a guide attachment engageable in said cylindrical bore for fixing the rotor cup axially with respect to the rotor shaft solely by magnetic attraction therebetween during spinning operation, said guide attachment having an exterior polyhedral surface for mating with said interior polyhedral receiving area for fixing the rotor cup rotationally with respect to the rotor shaft.

8. The rotor cup according to claim 7 , wherein the polyhedrons are hexagons.