Programmable inertial igniters for gun-fired munitions, thermal batteries and the like

A method for striking a percussion primer upon a predetermined acceleration profile, the method comprising:

• blocking a striker mass from striking the percussion primer with one or more stops when an applied acceleration and duration is less than the predetermined acceleration profile;
• moving the striker mass when the applied acceleration and duration is greater than the predetermined acceleration profile to both load a biasing element during the applied acceleration and remove the one or more stops as an obstacle to the striker mass striking the percussion primer;
• and
• moving the striker mass by the biasing element during a set forward period to strike the percussion primer.

An inertial igniter comprising:

• a housing having a base and containing a percussion primer;
• a striker mass movable within the housing;
• one or more movable members each having a stop for limiting movement of the striker mass in the direction of the percussion primer;
• and
• a first biasing member for biasing the striker mass towards the percussion primer;
• wherein the striker mass has a portion which engages a portion of the one or more movable members upon a predetermined acceleration profile to remove the stop as an obstacle of movement of the striker mass in the direction of the percussion primer thereby permitting the first biasing member to urge the striker mass against the percussion primer during a set forward period.