Double contact - security enhancements through keys with two switch levels
High operating safety requirements demand maximum reliability of the control unit. A speed function (slow/fast) controlling a crane, for example, requires two distinctly different switching functions. Hoffmann + Krippner has developed membrane switches with double contact functions specifically for such requirements.
For example, the first switching level is activated at a pressure of around 7N, and the second level at about 13N.
Sphere shaped domes in the membrane overlay on top of the keys (GT Technology) reinforce the clear tactile feedback of both switching levels.