Split Stepped Drum (UK), Geteilte Staffelwalze (DL) or the Monroe principle



The pictures above show an outside and inside view of an Nisa K5 machine, a Monroe clone, which uses the Split Stepped drum technology. In fact the Stepped drum is divided in two, one with 5 steps and one with 1 to 4 in steps. The flash video to the left shows this Split Stepped drum, with the keys 0 to 9 (from left to the right) pressed. In this situation you see all the possible settings of the two halve drums and how they are in line with the gears above.
When the keyboard is removed you will have an view of the way the Spilt drums are brought in position. The second video shows this.
One coulomb is showed on the photo below. The left plate is serving the left stepped drum, the one with five teeth. The right plate does it for the one to four drum.
A detail photo of the plates and the numbers is on the one to the left. How the keys pushing these plates is shown on the bottom photo. They have all the same shape. The shape is separated to the inserted picture.