| 摘要 |
PURPOSE:To drive a magnetic head with a simple structure, by providing spiral grooves and spiral projecting stripes, where directions of turn are opposite to each other, on both faces of one driving disc supported axially in parallel with a magnetic disc to guide reciprocation of a trace arm. CONSTITUTION:A driving disc 6 is supported axially on a rotation shaft 2 in parallel with a magnetic disc 5. Spiral grooves 9 for advance are provided on the lower face of the disc 6, and a pedestal part 8 is formed in the center of the disc 6. Spiral projecting stripes 10 are provided in a direction of turn opposite to that of spiral grooves 9 on the upper face of the disc 6. A trace stylus 19 is provided at the tip of a trace arm 20, and a head 17 and an engaging piece 24 are provided on and under the tip of a head arm 18 respectively. The disc 5 is held between a pad 15 at the tip of a pad arm 16 and the head 17. The trace stylus 19 guides the head 17 toward the center by the rotation of the disc 6; and when the head 17 runs onto the pedestal part 8, the engaging piece 24 is engaged with spiral projecting stripes 10 to evacuate the head 17 quickly. Thus, a simple structure where the driving source for the head is unnecessary is constituted. |
