Patent 7412928 was granted and assigned to Qinetiq Limited on August, 2008 by the United States Patent and Trademark Office.
An electronic safety and arming unit comprises a micro electromechanical system (MEMS) shutter device. The shutter (18) is suspended by thin lightweight arms and hinges, all formed by silicon processing of SOI substrates and includes holding latches for holding the shutter (18) in the closed position. The holding latches may be released by an electrothermal actuator. The shutter (18) separates an initiator section from an explosive train (6) of munitions such as shells, thereby providing safety until the shell is fired and away from its start point. After firing, the shutter (18) is opened ready for the main explosive to be detonated by the initiator (3). The shutter (18) may be suspended by a compliant displacement multiplier and may include an electrothermal actuator such as an electrically heatable bent beam. Heating of the beam causes movement of a shutter blade from a shut condition covering a firing aperture to an open condition. Alternatively the shutter (18) may operate by inertial centrifugal forces generated by a spinning munition. The shutter (18) may include latches for retaining the shutter in its open position.