Magnetic disc recording and reproducing device with damper and lock for head moving motor

Claim 1

A magnetic disc recording and reproducing device comprising: a rotatable magnetic disc; a magnetic head for reading/writing information on the magnetic disc; a magnetic head displacing mechanism on which said magnetic head is mounted and for displacing the magnetic head in the direction of a radius of the magnetic disc; an electric motor having a shaft connected to said mechanism for driving said displacing mechanism; a damper for damping the inertia force of said mechanism and the motor, said damper being connected to said shaft of said motor and having a housing which is rotatable with said shaft, and said housing having a plurality of notches on the outer circumferential surface thereof and spaced circumferentially therearound; and lock mechanism including a pawl member spring biased toward a lock position in which said pawl member is engaged in one of the notches to block the rotation of said housing, and a solenoid for acting on said pawl member to separate it from the notch against the spring biasing force when said electric motor is energized, whereby rotation of said housing is blocked when said motor is not actuated.