Abstract: A print head for a dot matrix printer comprises a housing (1) containing a number of actuators (2) driving a corresponding number of print wires (6). Each actuator (2) includes an actuating coil (11) wound around a yoke (10) fixed to the housing (1) and a pivotable armature (13) adjacent the yoke (10). The armature has one end pivotally connected to the housing by a hinge of rubber or rubber-like elastomeric material (26) and has its other end engaging the head of a print wire (6) so that, upon application of current to the actuating coil the pivotable armature (13) is attracted towards the yoke (10) and pivots about its one end causing its other end to drive the printwire (6) forwards. Preferably the pivoting armature (13) is formed by two separate parts, a soft iron pole piece (20) and an actuating finger (21). Preferably they are connected together by both a spot weld (22) and an adhesive. Preferably each actuator (2 ) also includes an adjusting screw (16) which bears against a damper (15).
Type:
Grant
Filed:
June 8, 1987
Date of Patent:
May 9, 1989
Assignee:
Russet Instruments PLC
Inventors:
John Sparshott, Stephen Butler, Richard Bowsher