Abstract: In one embodiment, a lock mechanism includes a control element arranged for rotation about an axis between an active position and an inactive position. The control element includes a control head having one or more axially extending projection(s). The lock mechanism further includes a lock element that is axially aligned with the control element and includes a lock element head. The lock element head has one or more axially extending projection(s). The projection(s) of the control head and the projection(s) of the lock element head are arranged such that in the active position, the lock element and control element are held apart by the projections, and such that in the inactive position, the projections can mesh together to permit axial movement of the lock element relative to the control element.