Rotational coupling device with armature release collar

A rotational coupling device, comprising:

• an armature having a shape that is complementary to a shape of a shaft such that the armature is configured for directly coupling to the shaft for rotation therewith about a rotational axis and for movement axially relative to the shaft;
• an electromagnet assembly disposed on a first axial side of the armature and fixed against rotation relative to the rotational axis;
• and,
• a collar disposed on a second axial side of the armature opposite the electromagnet assembly, the collar configured for rotation with the shaft, but fixed against axial movement relative to the shaft, the collar housing a first permanent magnet
• a controller configured to
• provide a current having a first polarity to the electromagnet assembly to establish an electromagnetic circuit between the armature and the electromagnet assembly to disengage the armature from the collar and urge the armature in a first axial direction into engagement with a member of the coupling device to transmit a torque between the member and the armature;
• and
• terminate the current to terminate the electromagnetic circuit between the armature and the electromagnet assembly, the first permanent magnet urging the armature in a second axial direction following termination of the electromagnetic circuit to disengage the armature from the member
• wherein the member of the coupling device comprises the electromagnet assembly and the torque brakes rotation of the armature.

A rotational coupling device, comprising:

• an armature having a shape that is complementary to a shape of a shaft such that the armature is configured for directly coupling to the shaft for rotation therewith about a rotational axis and for movement axially relative to the shaft;
• an electromagnet assembly disposed on a first axial side of the armature and fixed against rotation relative to the rotational axis;
• and,
• a collar disposed on a second axial side of the armature opposite the electromagnet assembly, the collar configured for rotation with the shaft, but fixed against axial movement relative to the shaft, the collar housing a first permanent magnet
• wherein the electromagnet assembly urges the armature in a first axial direction to disengage the armature from the collar and urge the armature into engagement with a member of the coupling device to transmit a torque between the member and the armature when a first current having a first polarity is provided to the electromagnet assembly and the first permanent magnet urges the armature in a second axial direction to disengage the armature from the member when a second current having a second polarity is provided to the electromagnet assembly.