A reciprocating electromechanical apparatus for controlling the operating modes of a pair of non-friction coupling assemblies, the apparatus comprising: first and second members (135, 170) including first and second faces, respectively, in close-spaced opposition with one another, the second member being mounted for rotation about an axis and for reciprocating movement along the axis; magnetic circuit components including first and second magnetic sources, the first magnetic source being supported by the first member at the first face in close-spaced opposition to the second magnetic source which is supported by the second member, the magnetic sources (166, 171) being separated by a radial air gap, wherein the second magnetic source is a magnetically-latching, permanent magnetic source having a permanent magnetic field and the first magnetic source is an electromagnetic source including a coil to create an electronically switched magnetic field; and wherein coil energization creates a temporary magnetic field which causes the second member to reciprocate between first and second predefined, discrete positions along the axis and wherein the permanent magnetic field causes the second member to reciprocate between first and second predefined, discrete positions along the axis and wherein the permanent magnetic field causes the second member to maintain the first and second positions without the need to maintain coil energization thereby providing a magnetic latching effect, and characterised by, a first cam having a first contour surface extending from the second member in a first direction to cause a first locking element of a first coupling assembly to ride on the first contour surface to transform reciprocating movement of the first cam to pivotal motion of the first locking element and a second cam having a second contour surface extending from the second member in a second direction opposite the first direction to cause a second locking element of a second coupling assembly to ride on the second contour surface to transform reciprocating movement of the second cam to pivotal motion of the second locking element. first and second members (135, 170) including first and second faces, respectively, in close-spaced opposition with one another, the second member being mounted for rotation about an axis and for reciprocating movement along the axis; magnetic circuit components including first and second magnetic sources, the first magnetic source being supported by the first member at the first face in close-spaced opposition to the second magnetic source which is supported by the second member, the magnetic sources (166, 171) being separated by a radial air gap, wherein the second magnetic source is a magnetically-latching, permanent magnetic source having a permanent magnetic field and the first magnetic source is an electromagnetic source including a coil to create an electronically switched magnetic field; and wherein coil energization creates a temporary magnetic field which causes the second member to reciprocate between first and second predefined, discrete positions along the axis and wherein the permanent magnetic field causes the second member to reciprocate between first and second predefined, discrete positions along the axis and wherein the permanent magnetic field causes the second member to maintain the first and second positions without the need to maintain coil energization thereby providing a magnetic latching effect, and characterised by, a first cam having a first contour surface extending from the second member in a first direction to cause a first locking element of a first coupling assembly to ride on the first contour surface to transform reciprocating movement of the first cam to pivotal motion of the first locking element and a second cam having a second contour surface extending from the second member in a second direction opposite the first direction to cause a second locking element of a second coupling assembly to ride on the second contour surface to transform reciprocating movement of the second cam to pivotal motion of the second locking element.