Three-terminal pushbutton microswitch - has tensioned changeover contact with minimal spring movement to reduce switching hysteresis

摘要

Microswitch is designed to minimise switching hysteresis. The case (10) of the microswitch has the bearing surface and guide (52) for the switching spring (38) and pivot (46) inset into one side. The pivot (46) is firmly fixed to the case (10) and the end (44) of the spring (38) wound around it. The switch plunger (22) is located on the turned up end (58) of the hinged switch tumbler unit (20) and depressing it changes over the centre contact (30, 32) between the two switch fixed contacts (34, 36). The spring (38) travel is limited by the shape of the guide (54) extending above it and moves very little during switch movement; it serves as a bias tensioning spring to enable switching hysteresis to be reduced to 0.1 mm.