For machinery comprising rotary components attached to at least one drive
shaft, at least one rotary bearing to position the drive shaft with a
rotational freedom of movement about a drive shaft axis and associated
stationary components, apparatus that comprises: a rotary backup bearing
sleeve attached to the drive shaft proximate the bearing comprising a
rotary radial surface relative to the drive shaft axis and a rotary axial
surface relative to the drive shaft axis; and a stationary backup bearing
collar mounted to one of the stationary components proximate the rotary
backup bearing sleeve comprising a stationary radial surface relative to
the drive shaft axis proximate the rotary radial surface with a
predetermined axial clearance and a stationary axial surface relative to
the drive shaft axis proximate the rotary radial surface with a
predetermined axial clearance.