Field replaceable print hammer

Abstract

A hammer assembly for incorporation in a hammer bank assembly useful in high-speed impact printers of the type generally employed in data processing systems is disclosed to comprise an impact tip carried on a rigid coil structure disposed in a permanent magnet field, a foot member for precisely, removably positioning the hammer assembly with respect to the hammer bank assembly, and first and second conductive spring members supporting the rigid coil structure from the foot member and, concurrently coupling the ends of the coil within the rigid coil structure to electronics associated with that particular hammer located within the impact printer. The first and second spring members serve to provide a restoring force to return a rest position within the hammer bank assembly after impact energization of the coil has been discontinued. The first and second spring members extend through the foot member and are formed to have U-shaped contact terminals on their free ends which may be removably inserted into specially adapted receptacle holes coupled appropriately with the hammer drive electronics. The first and second spring members are appropriately pre-bent to readily enable removal and insertion of the hammer assembly from and to its appropriate position within the hammer bank assembly. Appropriate segments of the extent of each of the first and second spring members are formed to have a reduced cross-sectional dimension in a plane of bending between the foot member and the specially adapted insertion holes. The insertion holes are formed to have two keyways, diametrically opposed, to receive the external shape of the arms of the U-shaped contact terminals of the spring members.