Bull Hn Information Systems, Inc.

Honeywell Bull Italia S.p.a.

Sergio Cattaneo

Needle printing head of the permanent magnet type where the armatures of a plurality of printing actuators are attracted, in rest position, against the poles of a permanent magnet and released in printing position by the 'cancellation' of the magnetic flux caused by control windings and where the impact of the armatures against the permanent magnet poles, when they return to the rest position is damped by a multilayer element interposed between armatures and magnetic poles and consisting in two thin sheets of magnetic steel between which a thin film of resilient material such as polyester is interposed.

Needle printing head

An armature group for mosaic printing head has a plurality of armatures wherein each armature which is part of an actuation electromagnet associated with one of a plurality of printing needles, is fixed to an elastic arm of a spring steel spider having as many arms as there are armatures. The spider, besides performing an armature positioning function allows the armature group to be handled as a unitary element which is easy to assemble. The thrust arm of each armature further has a double bend so that the plane between such arm and the corresponding needle head is perpendicular to the axis of the needle and passes through the fulcrum of the armature. This minimizes the buckling force which the needle has to undergo during the actuation phase. The construction of the armature group can be accomplished by a completely automated manufacturing process.

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Rho, Italy

Sergio Cattaneo