Abstract: Locking means for preventing displacement of a displaceable member relative to a stationary member by means of an armature operatively associated with an electromagnet, the armature having a bipartite structure: a locking pin member engageable with the displaceable member and a sleeve member coaxially surrounding the locking pin member located on an end of an armature extending from the electromagnet. A plurality of radially mobile balls interact within bores in a portion of the stationary member extending between the locking pin member and the sleeve member to engage grooves in the locking pin member to lock or secure same in a position in which the locking pin member is engaged with the displaceable member. Selective energization of the electromagnet selectively positions the sleeve member and a groove located within an interior wall of the sleeve member to selectively limit radial movement of the balls. In a deenergized state, the electromagnet permits axial displacement of the locking pin member.