A breakaway unit sits atop a base plate of a coordinate measuring machine
via a breakaway coupling system. A crash detection system including at
least one crash detection sensor mounted on the breakaway unit and a
crash detection controller stops the machine when vertical movement of
the breakaway unit exceeds a threshold. Should collision occur, the
breakaway coupling system allows the breakaway unit to separate from the
base plate, preventing damage to instruments mounted thereon. The
kinematic coupling system preferably comprises tooling balls engaging
respective vee cones, vee grooves, and/or flats.