INFORMATION TRANSDUCER LOAD CONTROL SYSTEM AND METHOD, PARTICULARLY APPLICABLE IN A MAGNETIC DISK DRIVE APPARATUS

摘要

An information transfer apparatus and method in which a transducer 150F is movable by a solenoid 130F from an inoperative position separated from a moving information carrying magnetic disk 20F towards the disk into engagement therewith in response to a transducer load command signal on line 208 which is applied to a control system connected to the solenoid to energise it. The application of the signal on line 208 to the control system is delayed by a variable time period so that the transducer is applied to the disk at a random time after the command signal is on line 208. A free running oscillator 206 sets a latch 202 which has been reset by the signal on line 208 to achieve this random delay. In addition, the control system is such as to produce an initial fast rising current in the solenoid to move the head quickly into close proximity with the disk, a slowly rising subsequent current in the solenoid to engage the head with the disk gradually, and a final fast rising current in the solenoid for completing the engagement pressure of the head on the disk.