A locking positioning mechanism includes a first element and a second
element, the first element and second element rotatable relative to one
another about a common rotational axis between a locked orientation and
an unlocked orientation and axially translatable relative to one another.
The mechanism further includes one or more first locking surfaces of the
first element and one or more second locking surfaces of the second
element. The second locking surfaces are configured to clear the first
locking surfaces in the unlocked orientation. The second locking surface
is configured for an interference fit with a first locking surface in the
locked orientation.