Actuation mechanism for actuating a device and method for actuating a device

An actuating mechanism for actuating a device, the actuating mechanism comprising:

• a base having a helically shaped passage;
• a movable mass having a helically shaped projection, a first surface of the helically shaped projection mating with a corresponding second surface of the helically shaped passage;
• and
• a spring for biasing the first surface of the helically shaped projection of the movable mass against the second surface of the helically shaped passage when the base is not being accelerated;
• wherein the helically shaped passage, the helically shaped projection and the spring are configured to maintain the helically shaped projection in a first portion of the helically shaped passage upon the base experiencing a first acceleration profile having a first magnitude and a first duration and allow the mass to move to a second portion of the helically shaped passage upon the base experiencing a second acceleration profile having a second acceleration lower than the first acceleration and a second duration greater than the first duration.