Browse Prior Art Database

Actuator Retraction Device

IP.com Disclosure Number: IPCOM000086555D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Hearn, AR: AUTHOR

Abstract

Fig. 1 shows an actuator mechanism for a disk file of the type disclosed in United Kingdom Patent Specification 1,342,495. The actuator consists of an arm 1 mounted for rotational motion about a pivot 2. A record/ playback head 3 is supported at one end of the arm 1. A voice coil 4, cooperating with a fixed E-shaped permanent magnetic stator 5, is supported on a former 6 at the other end of the arm. By energizing the voice coil 4 with drive currents of appropriate magnitude and polarity, the head 3 can be moved from one track to another over a rotating disk surface 7 in order to perform transducing operations thereon.

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Actuator Retraction Device

Fig. 1 shows an actuator mechanism for a disk file of the type disclosed in United Kingdom Patent Specification 1,342,495. The actuator consists of an arm 1 mounted for rotational motion about a pivot 2. A record/ playback head 3 is supported at one end of the arm 1. A voice coil 4, cooperating with a fixed E- shaped permanent magnetic stator 5, is supported on a former 6 at the other end of the arm. By energizing the voice coil 4 with drive currents of appropriate magnitude and polarity, the head 3 can be moved from one track to another over a rotating disk surface 7 in order to perform transducing operations thereon.

Fig. 2 shows a cross-section of the stator and voice coil mounting when viewed in the general direction of arrow 8. The voice coil 4 and former 6 are shown here in the "home" position at the limit of inward movement within the stator 5. This position is shown in part by the chain dotting in Fig. 1. When not in use, it is desirable for the actuator to be retracted to this "home" position and thereafter to be held there until next required. This retraction function is performed automatically by a triangular-shaped thin film 9, of ferrite or some other soft magnetic material with high electrical resistance, attached to the inside of former 6. By virtue of its shape, the film 9 reduces the magnetic gap reluctance linearly as the coil moves towards its "home" position. Accordingly, the presence of the ferrite in the gap produc...