| 摘要 |
A key for printed circuit boards comprises an electrically conductive snap disk embedded in a recess in a spacer layer between a cover foil and a board coated with printed conductors. The key is used as an opener key with a pressing point, to which end, the snap disc has contact tabs and, offset therefrom tension tabs. The tension tabs are fixed to the board with biasing in order to produce the necessary contact pressure in the unactuated state. Each contact tabs has a shoulder which is curved towards the board and which upon actuation of the snap disk bears on the board and, with increasing actuating force, reduces the contact force (Fc) of the contact tab until the contact surface disengages. Disengagement of the contact surfaces and the passage through the pressure point or peak value for the actuating force (Fa) occurs at the same deformation travel (d) of the snap disk. |
