International Business Machines Corporation

Joseph E Wallace

Han C Wang

Ralph D Silkensen

Gerald A Daughenbaugh

Arthur E Moxley

George F Pennell

Philip W Koob

A two-lever electromagnetic print actuator having a pivoted bellcrank armature and an end-pivoted print hammer is urged to free-flight by energy transfer at an energy transfer contact surface. The armature pivot, print hammer pivot and energy transfer surface are aligned in sequence and substantially coplanar. This converts input energy to optimum print velocity with minimum wear. In operation, energizing a coil attracts the armature to the stator, imparting energy to an energy transfer surface on an energy transfer armature leg. The energy transfer surface moves in an arc, delivering energy to a related energy transfer surface on the print hammer. The print hammer goes into pivoted free-flight when the armature strikes a stop pad. There is mimimum sliding, and thus minimum wear, between the energy transfer surfaces of the print hammer and armature as they both move in arcs of similarly convex circles which remain tangent at their contact point. The two-lever print actuator provides a low mass print hammer with a short contact time; the hammer moves at a substantially higher velocity than the armature at the pole face due to the optimized lever length ratios.

Two lever print actuator with aligned pivots and energy transfer surfaces

A magnetoresistive head assembly comprises a silicon substrate, a magnetoresistive element mounted on the substrate, and sapphire members formed around said substrate in a sandwich type configuration. The portion of the head which interacts in transducing relation with a magnetic medium is so configured as to realize improved wear characteristics as well as good heat dissipation with low thermal noise.

Sandwich type magnetoresistive read head

A flux extender or guide for a magnetic read head having a magnetoresistive read element. The element is mounted on a substrate, contained, for example, in a hand-held wand structure. The element is spaced from the contact portion of the wand, to permit a small amount of wear of the head to take place, before the read element comes into contact with the record media. In order to increase the spacing between the magnetoresistive element and the contact portion of the wand, the flux guide or extender is utilized. The flux guide or extender is a wedge-shaped piece of magnetizable material. At the end of the flux guide closest to the read element, the guide is approximately as wide as the element and tapers down to approximately three quarters of its top width at the lower end of the guide. The guide is of uniform thickness and thicker than the read element. The cross-sectional area is selected to be from two to three times the cross-sectional area of the read element. The flux guide is preferably fabricated from a magnetic material which is non-corrosive or less corrosive than the read element and having a higher value of flux density than the element. The width of the guide at the lower end is less than the width of the element, which permits higher density of magnetized bits per inch to be decoded. Also, the length of the guide is less than the minimum distance between flux transitions for good resolution.

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Charlotte, NC, United States of America

Joseph E Wallace