Device and procedure for retracting a head and control switch for head restraint

摘要

A head retracting method retracts a head (26) to a retract position away from a disk (12) to perform a stable unload operation when a power supply failure occurs, regardless of the position and the velocity of the head. When the power supply failure occurs, a controller (40) ensures that the head reaches an inner stopper (22), which is at a predetermined position in an opposite direction from a ramp (20), so as to stop at the inner stopper at a predetermined position without forcibly colliding therewith, regardless of what position the head is and regardless of the velocity the head is moving at. The head is unloaded from the predetermined position by constant voltage driving, so that the head contacts the ramp (20) and climbs onto the ramp at a predetermined velocity.