Browse Prior Art Database

Actuator

IP.com Disclosure Number: IPCOM000097989D
Original Publication Date: 1961-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Kochenburger, RJ: AUTHOR

Abstract

The device positions a recording head over a selected track recorded on a disk. The moving coil arrangement includes a magnet that generates a flux field by the energization of windings 12. The magnet consists of central pole 14 and outer return path 16. Located between pole 14 and path 16 is a first movable pole piece 18 and a second movable pole piece 20. Pole pieces 18 and 20 are connected to rods 22 for motion in the lateral plane. Rods 22 are connected to nut 23, moved by rotation of lead screw 24. Lead screw 24 is connected through spur gearing 26 and 28 to servomotor 30. Moving coil bobbin 32 is located in the gap formed by pole pieces 18 and 20. Attached to 32 is forked arm 34 which is connected to magnetic head 36. A primary coil (not shown) is wound upon bobbin 32 and connects to power amplifier 38 by line 50.

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Actuator

The device positions a recording head over a selected track recorded on a disk. The moving coil arrangement includes a magnet that generates a flux field by the energization of windings 12. The magnet consists of central pole 14 and outer return path 16. Located between pole 14 and path 16 is a first movable pole piece 18 and a second movable pole piece 20. Pole pieces 18 and 20 are connected to rods 22 for motion in the lateral plane. Rods 22 are connected to nut 23, moved by rotation of lead screw 24. Lead screw 24 is connected through spur gearing 26 and 28 to servomotor 30. Moving coil bobbin 32 is located in the gap formed by pole pieces 18 and 20. Attached to 32 is forked arm 34 which is connected to magnetic head 36. A primary coil (not shown) is wound upon bobbin 32 and connects to power amplifier 38 by line 50.

In operation, a computer requests a new position in digital form of comparator circuit 40 via input line 42. The present position of head 36 is transmitted to 40 in digital form via line 44.

This information is logically compared by 40 which generates a position-error signal. This indicates the magnitude and direction that head 36 must move to relocate. The result is converted to an analog voltage and transmitted to amplifier 38 via output line 46.

The output 50 of 38 drives the primary coil wound upon bobbin 32 to move head 36to the new position. As 36 approaches the new address, output 46 of 40 diminishes until the current fed to the primary coil is reduced to zero.

As bobbin 32 moves, its centerline moves away from the centerline of the gap existing between pole pieces 18 and 20. There are secondary windings 52 and 54 wound on 32. As 32 moves relative to the gap, coils 52 and 54 gener...