Inertial igniters for low-G and long duration firing acceleration munitions and the like
An inertial mechanism including an activating mechanism and a time delay mechanism coupled to the activating mechanism for delaying a time in which the activating mechanism is activated after a predetermined acceleration profile occurs. Where a coupling of the time delay mechanism with the activating mechanism to activate the activating mechanism initially moves away from the coupling when the predetermined acceleration profile occurs before the coupling occurs after a time delay.
1. An inertial mechanism comprising:
an activating mechanism; and
a time delay mechanism coupled to the activating mechanism for delaying a time in which the activating mechanism is activated after a predetermined acceleration profile occurs;
the activating mechanism comprising:
a first mass body movable between a first position and a second position, the first mass body having a first surface and a second surface;
a first biasing member for biasing the first mass body in the first position;
a second mass body movable between a third position corresponding to the first position of the first mass body and a fourth position corresponding to the second position of the first mass body, the second mass body having a third surface and a fourth surface engaged with the first surface of the first mass body when the second mass body is in the third position; and
a second biasing member for biasing the second mass body in the third position; and
the time delay mechanism comprising:
a third mass body movable in a direction of acceleration, the third mass body having a fifth surface;
a fourth mass body having a sixth surface for engaging with the fifth surface of the third mass body when the third mass body moves from a fifth position to a sixth position upon occurrence of the predetermined acceleration profile, the forth mass body having a seventh surface engaging with the third surface of the second mass body to activate the activating mechanism after a time delay; and
a third biasing member for biasing the seventh surface towards engagement with the third surface;
wherein the fifth and sixth surfaces are configured such that the fifth surface engaging with the sixth surface upon the occurrence of the predetermined acceleration profile causes the seventh surface to initially move away from engagement with the third surface before moving the seventh surface to engage with the third surface after the time delay; and
the second surface of the first mass body is configured to one of:
ignite a pyrotechnic upon occurrence of the predetermined acceleration profile; or
one of open or close an electrical circuit upon occurrence of the predetermined acceleration profile.
2. The inertial mechanism of claim 1 , wherein the time delay mechanism is configured to undergo an oscillatory movement during the time delay.
3. The inertial mechanism of claim 1 , wherein:
the first mass body and the second mass body move in rotation; and
the third mass body and the fourth mass body move in translation.
4. The inertial mechanism of claim 1 , wherein one or more of the first, second and third biasing members are springs.
5. The inertial mechanism of claim 1 , wherein the first mass body further having an eighth surface, wherein:
one of the second surface and the eighth surface of the first mass body is configured to ignite a pyrotechnic upon occurrence of the predetermined acceleration profile; and
the other of the second surface and the eighth surface of the first mass body is configured to one of open or close an electrical circuit upon occurrence of the predetermined acceleration profile.
6. The inertial mechanism of claim 1 , wherein:
the sixth surface of the fourth mass body is configured to be movable between a seventh position into engagement with the third surface of the second mass body and a eighth position out of engagement with the third surface of the second mass body;
the sixth surface being biased into the eighth position and movable into the seventh position upon occurrence of the predetermined acceleration profile.
7. The inertial mechanism of claim 1 , wherein:
the third surface of the second mass body is configured to be movable between a seventh position into engagement with the sixth surface of the fourth mass body and a eighth position out of engagement with the sixth surface of the fourth mass body;
the third surface being biased into the eighth position and movable into the seventh position upon occurrence of the predetermined acceleration profile.
8. The inertial mechanism of claim 1 , wherein:
the sixth surface the fourth mass body is configured to be movable between a seventh position into engagement with the third surface of the second mass body and a eighth position out of engagement with the third surface of the second mass body;
the sixth surface having a first sub-surface and a second sub-surface opposing the first sub-surface;
the third surface having a third sub-surface and a fourth sub-surface opposing the third sub-surface, the first sub surface facing the third sub surface in a biasing direction in which the fourth mass body moves under a biasing force of the third biasing member; and
the first sub-surface of the sixth surface contacting the third sub surface of the third surface to activate the activating mechanism upon the occurrence of the predetermined acceleration profile when the third mass body moves in the biasing direction of the third biasing member.
9. The inertial mechanism of claim 1 , wherein:
the sixth surface the fourth mass body is configured to be movable between a seventh position into engagement with the third surface of the second mass body and a eighth position out of engagement with the third surface of the second mass body;
the sixth surface having a first sub-surface and a second sub-surface opposing the first sub-surface;
the third surface having a third sub-surface and a fourth sub-surface opposing the third sub-surface, the second sub surface opposing the fourth sub surface in a biasing direction in which the fourth mass body moves under a biasing force of the third biasing member; and
the second sub-surface of the sixth surface contacting the fourth sub surface of the third surface to activate the activating mechanism upon the occurrence of the predetermined acceleration profile when the third mass body moves in a direction opposing the biasing direction of the third biasing member.