公开(公告)号：US3576454A

公开(公告)日：1971-04-27

申请号：US3576454D

申请日：1968-03-28

Applicant: IBM

Inventor： BEACH LAURENCE R JR ,  BLACK ROBERT J

IPC: G11B5/54 ,  G11B5/55 ,  H02K41/035 ,  H02K1/20 ,  G11B21/08

CPC classification number: G11B5/54 ,  G11B5/5521 ,  H02K41/035 ,  H02K41/0356

Abstract: Apparatus for moving transducers into or out of engagement with a recording medium and for adjusting the position of the transducer laterally with respect to tracks to thereby selectively access those tracks. The apparatus includes a DC linear electric motor employing external magnets. The specific arrangement comprises a plurality of permanent magnets arranged on either side of, and parallel to, a magnetically permeable center pole piece. The rear of the magnets and the center pole piece are connected by a magnetically permeable plate. A front magnetically permeable plate interconnects the magnets at the other end and forms a gap surrounding the center pole piece. A hollow coil is mounted on a carriage and is slidably inserted through the gap and over the center pole piece. The transducers are then mounted on the carriage. The arrangement focuses the magnetic flux across the gap whereby electrical energization of the coil causes the coil to be moved in one direction or the other along the center pole piece, thereby moving the carriage and the transducers longitudinally, and hence, laterally with respect to tracks on the recording medium.