6-row action in conventional construction from Chromatiphon

The keys of rows 1, 2, 3 control the two rows of valves on the left of the picture with their long key levers. The keys of row 4 control with short (invisible) key levers a third, faintly visible under the key levers row of valves (white arrow). The buttons of the outer auxiliary rows 5 and 6 are connected to rows 1 respectively 2 by metal arms.

The smallest possible distance between the key levers is determined by the width of the valves attached to the ends of the key levers. The key levers cannot be narrower than half a valve's width.

At the top and bottom, an elaborate extra holder for a total of 5 keys is necessary (arrows on the right)

To avoid the curved metal arms, the key levers from rows 1 and 2 must be extended to the position of auxiliary rows 5 and 6.

The row 4 key does not bother, because its base can be kept just as narrow as the key levers that can be passed under it. The lateral offset between the main and auxiliary rows can be bridged by means of an angle attachment.

Theoretically, therefore, the metal arms could actually have been omitted by modifying this conventional control mechanism.

Perhaps the main reason for the development of the Reformklaviatur was the saving of the two extra holders (the lower one with an arrow) with the space gain for 3 additional keys, and the easier coupling of the auxiliary rows was a welcome additional effect. To know this, one would have to be able to question him yourself...

The constructive solution. It was named Refomklaviatur by Hugo Stark.

The closely spaced levers in groups of 4 are immediately noticeable, corresponding to the 4 inner main rows of keys of the Chromatiphon. The two outer auxiliary rows are mechanically connected to rows 1 and 2 respectively. In the place of the lower extra bracket, 3 buttons (red) have been added.

The levers can be so close together because there are no more valves attached to their ends. But how are the valves then lifted?

Stark's solution can be described as ingenious without exaggeration:

The key idea was to separate the valves from the key levers. Each valve has a short lever mechanism that can be used to lift it by applying pressure.

Because, in contrast to conventional control units, each key lever is located above all 3 rows of valves, it is possible to control each row of valves.

Once the crossbar has been removed, all button levers can be easily repositioned via their rear pivot axis, allowing free access to the valves.

The selection of valve is simply made with a small pan-head screw attached to the underside of the lever, as shown above in the picture.

It is screwed in the position of the desired valve lever and the release point is simultaneously fine-tuned via its height.

It can also be seen that the lever and valves are not only no longer connected, but also no longer have to be in line. If the valves lever is mounted at an angle, the valves can also be positioned to the side of the key lever.

All in all, an ingeniously flexible and easily accessible construction.

It is also easy to connect the auxiliary rows.

The key levers of rows 1 and 2 extend to the respective auxiliary row. A metal bracket is attached to the end of the key lever on which the button of the auxiliary row sits.

Self-description of the reform keyboard:

"Greatest advantages!
No clapping of the valves!
Best function!
Narrowest, even partition!
...can be easily and quickly dismantled and reassembled by anyone in just a few minutes...
...produces an even response for all tones, which is a great advantage for piano and continuo playing."

5-row C-fingering Reformklaviatur

Starke's invention has been used among other for the bandonion models Meisel and Praktikal (next) with their 2 auxiliary rows of the C/B fingering keyboard. These have only 3 main rows compared to 4 of the Chromatiphon

Around 2005, the Reformklaviatur is used again on the improved Kusserow and saves on costly sheet metal bending.