Magnetic printing system with plunger type armature - has two-section yoke fixed in collar against flange and excitation windings are pulled over bush

摘要

A magnetic system is used with a plunger type armature (5) which has two yoke sections in the form of a hollow cylinder and is connected to a printing needle (7). They are fitted inside the coil windings, and are very accurately aligned leaving an air gap. The cylindrical shape allows axial movements of the armature. The two sections of the yoke (1, 2) are rigidly fixed inside a bush (8) which is made from non ferromagnetic material. The yoke sections are held in position by the excitation windings (4). The bush rests against the outer flange formed by the yoke sections. The unit is assembled by mounting the yoke and bush onto a mandrel and pulling the coil over the bush.