Electromagnetically operable ram actuator in particular for impact printers

US4371857A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Armin Bohg · Altensteig, DE
• Kurt Hartmann · Duisburg, DE

Key dates

• Filing date: May 7, 1981
• Grant date: Feb 1, 1983
• Expiry date: May 7, 2001

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41J9/38
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

An electromagnetic ram actuator, the electromagnet of which consists of two symmetrically designed magnetizable yoke halves. The facing pole ends of the yoke halves are in each case essentially semicircularly recessed, forming two aligned essentially circular operating gaps. Between the operating gaps a ram is arranged which is shiftable in the direction of their line of alignment and whose cross-section is adapted to the area of the operating gaps. The ram comprises two armature disks of magnetizable material and a spacer element arranged therebetween consisting of predominantly non-magnetizable material. One armature disk is associated with each operating gap. The armature disks are geometrically designed in such a manner that their volume is of the order of the operating gap volume. In the starting position of the ram the armature disks are positioned in front of the operating gaps of the electromagnet in its non-excited state. Upon excitation of the electromagnet, they are pulled into its operating gaps, being accelerated in the process. The ram actuator is particularly suitable for use in impact printers.