Abstract: An actuator with a predetermined failure mode includes two carriers which are each moveable in a common direction. A detent is engageable to couple the carriers to move in unison. An electrically operated actuating device causes extension of the toggle linkage to operate the detent and collapse of the toggle linkage when de-energized. There is a prime mover for the first carrier and a return mover for causing return movement of the second carrier on the release of the detent. In an example, the detent includes a pivoted arm disposed on the first carrier and positioned to engage a part of the second carrier; and the toggle linkage includes a pair of relatively pivoted links connected between a pivot on the first carrier and a pivot on the arm.

Abstract: An actuator with a predetermined failure mode comprises two carriers which are each moveable in a common direction. A detent is engageable to couple the carriers to move in unison. An electrically operated actuating device causes extension of the toggle linkage to operate the detent and collapse of the toggle linkage when de-energised. There is a prime mover for the first carrier and a return mover for causing return movement of the second carrier on the release of the detent. In an example, the detent comprises a pivoted arm disposed on the first carrier and positioned to engage a part of the second carrier; and the toggle linkage comprises a pair of relatively pivoted links connected between a pivot on the first carrier and a pivot on the arm.