Magnetic circuit for matrix print head

US4695174A · kind A · utility

Assignee

• Mannesmann AG · DE

Inventors

• Bernd Gugel · Erbach, DE
• Harald Niebel · Senden, DE
• Hubert Ott · Bad Abbach, DE

Key dates

• Filing date: Jan 27, 1986
• Grant date: Sep 22, 1987
• Expiry date: Jan 27, 2006

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41J2/28
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A matrix print head includes a magnetic yoke plate, magnetic pole defining cores annularly arranged on the yoke plate, electromagnetic coils mounted on the cores, a permanent magnet plate arranged in magnetic conductive relationship to the yoke plate; the yoke plate, the cores, coils, and permanent magnet plate establishing an electromagnetic assembly, there being additionally an armature assembly including an armature plate and a plurality of deflectable radially extending armature arms, the armature assembly being arranged in relation to the electromagnetic assembly such that the armature arms cooperate with the electromagnetic cores, there being print elements such as styli connected to the armature arms; the improvement disclosed is comprised of the following features, the armature plate and the armature arms are physically separated from each other but resiliently interconnected to establish a single uncritical parasitic air gap; and the magnetic yoke and armature plates are radially, inwardly recessed vis-a-vis the permanent magnet plate. A radially inwardly and outwardly recessed intermediate plate is interposed between the permanent magnet and the armature ring.