US Patent 7126446 Self-retracting fully compliant bistable micromechanism

A micromechanism (104) with two unique, stable configurations is disclosed. The micromechanism (104) has a base member (120) and a shuttle (122) designed to move in linear fashion. The shuttle (122) is coupled to the base member (120) via a coupling (26) in which flexible members (50, 52) are placed under axial tension in addition to bending. The coupling (26) also has a compressive member (54) that is compressed as the flexible members (50, 52) are placed in tension. The shuttle (122) has a displacement between the stable configurations that is suitable for use with thermomechanical microactuators and microswitching applications. Such a micromechanism may have multiple couplings (26), which may be disposed on either side of the shuttle (122) and may be attached to multiple base members (120). An electric return signal may be applied to the micromechanism to thermally relax the couplings (26), thereby promoting the micromechanism (104) to return from the second stable configuration to the first stable configuration. Alternatively, a separate return actuator may be used.