Selector unit for rotatable type drum - has two type shafts bearing type which can be applied to neighbouring platen

摘要

The type drum consists of an upper and lower plate between which run the two type shafts having a toothed segment, a toothless guide section and a magnetically influenced cam. The segment lies in a guide ring providing gaps for teeth in the region near the printing roller. The guide ring can rotate about a central shaft and is held in an initial position by a spring fixed at one end to the machine frame. An electromagnet with an iron core and coil is mounted in the plane of the cam and fixed to the frame. By energising the magnet, the cam is moved in a rotational direction to effect printing.