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Permanent Magnet Armature Heel Restraint

IP.com Disclosure Number: IPCOM000040138D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Related People

Thorne, WD: AUTHOR [+3]

Abstract

Illustrated are several methods of achieving magnetic flux retention of the heel of the movable armature or clapper in a wire matrix print head that replaces the usual hold-down springs or other retention means. In Fig. 1, the armature actuator arm 1 has a driving end 2 adjacent the driven head end 3 of a print wire 4 in the wire matrix print head. Electromagnet 5, when energized, attracts the armature 1 moving its tip 2 to drive end 3 of wire 4, as is customary. Magnetic flux from the electromagnet 5 passes through a flux return path which is part of frame 6 and back to the heel 10 of armature 1. Ordinarily, springs or pivot means are required to hold the heel 10 in position on frame 6. In Fig.

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Permanent Magnet Armature Heel Restraint

Illustrated are several methods of achieving magnetic flux retention of the heel of the movable armature or clapper in a wire matrix print head that replaces the usual hold-down springs or other retention means. In Fig. 1, the armature actuator arm 1 has a driving end 2 adjacent the driven head end 3 of a print wire 4 in the wire matrix print head. Electromagnet 5, when energized, attracts the armature 1 moving its tip 2 to drive end 3 of wire 4, as is customary. Magnetic flux from the electromagnet 5 passes through a flux return path which is part of frame 6 and back to the heel 10 of armature 1. Ordinarily, springs or pivot means are required to hold the heel 10 in position on frame 6. In Fig. 1, the holding force is supplied by magnetically permeable interposer 8 having a tip 9 in contact with the heel 10 of the armature 1. A permanent magnet ring 7 is in magnetic contact with the interposer 8 and supplies a hold-down flux whose flux path couples through

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the air, as illustrated. This keeps the heel 10 of armature 1 retained in position and, if the permanent magnetic ring 7 is properly polarized, will aid the electromagnet's flux path to create additional holding force, will further reduce the reluctance of the magnetic path through the frame member 6 to enhance the electromagnetic flux, and will result therefor in an increase in print force and more stable operation. Fig. 2 illustrates an alternative des...