Modular Impulse G-Switch for Compact Thermal Battery Ignition
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Solution Overview
Problem
Current inertial igniters for thermal batteries are large, unsuitable for small and low-power applications, and lack the necessary safety mechanisms to differentiate between accidental and intended acceleration events, leading to potential accidental ignition and high manufacturing costs.
Innovation Solution
Development of miniature inertial igniters that are scalable, safe, and reliable, capable of initiating pyrotechnics at specific acceleration levels without external power sources, with integrated safety mechanisms to prevent accidental ignition and designed for integration directly onto thermal batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inertial igniters are used in thermal batteries, then reliable ignition is achieved, but device volume and height increase significantly
Solution Approach 1:
The G-switch is divided into modular components including a housing, inertia member, actuator, and contact assembly that can be manufactured separately and assembled. This segmentation enables compact packaging while maintaining the functional integrity and reliability of the ignition system.
Solution Approach 2:
The patent implements a nested structure where the inertia member is positioned within the housing, the actuator is nested within the inertia member, and the contact assembly is integrated within the actuator mechanism. This nesting arrangement maximizes space utilization and reduces overall device volume while preserving ignition reliability.
2Object-generated harmful factors
If conventional inertial igniters are used, then ignition function is provided, but manufacturing cost increases due to labor-intensive processes
Solution Approach 1:
The G-switch is pre-configured with the inertia member, actuator, and contact assembly in specific positions during manufacturing. The spring is pre-compressed and the locking mechanism is pre-set, allowing for automated assembly processes that reduce labor intensity while ensuring the safety function is properly implemented.
Solution Approach 2:
The patent employs standardized parameters for the inertia member mass, spring constant, and trigger acceleration threshold that can be optimized through computational design and manufactured with precision. This parameter-based approach enables consistent safety performance across production batches while facilitating automated manufacturing processes.
3Reliability
If impulse-based G-switch mechanism is implemented, then differentiation between accidental and intended acceleration is achieved, but device complexity increases
Solution Approach 1:
The G-switch mechanism serves multiple functions: it acts as both an acceleration sensor and a safety discriminator, while also providing the mechanical actuation for ignition. The inertia member simultaneously detects acceleration magnitude and duration, eliminating the need for separate sensing and actuation systems and reducing overall device complexity.
Solution Approach 2:
The G-switch is designed to automatically differentiate between accidental and intended acceleration events through its inherent mechanical properties. The inertia member and spring system self-regulate based on the impulse characteristics of the applied acceleration, requiring no external control systems or complex electronic circuits to achieve safety discrimination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The miniature inertial igniters significantly reduce volume and height, enhance reliability, and simplify storage, while ensuring safe operation by differentiating between accidental and intended acceleration events, thus meeting the requirements for small thermal batteries in munitions applications.
Implementation Method 1
A compact, impulse-based mechanical G-switch is disclosed that activates the switching action to open and/or close at least one electrical circuit when it is subjected to a prescribed acceleration level acting over a prescribed time duration
Data Source
AI summary
A G-switch including: a base and posts, the posts having a hole; a locking ball with a portion disposed in the holes; a striker mass movably disposed relative to the posts and having a concave portion, wherein a portion of the locking balls is disposed the concave portion; a collar movable relative to the posts; a biasing element for biasing the collar in a position which retains the locking balls within the concave portions, the biasing element permitting movement of the collar to a position in which the locking balls are released from the concave portions to release the striker mass upon a predetermined acceleration profile; and a member on the striker mass and first and second electrically conductive contacts on a portion of the body, the first member opening or closing an electrical circuit between the first and second contacts upon release of the striker mass.