Pyrotechnic Switch Structure Using a Breakable Third Conductor
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Solution Overview
Problem
Existing pyrotechnic switches for high current applications require large and costly actuators due to the need to break thicker conductors, leading to bulky and expensive switch arrangements, and struggle with effective arc interruption.
Innovation Solution
A switch design using three separate conductors with a temporary joint, where a breakable retaining member allows the third conductor to move between the first and second conductors, reducing the force required for opening and incorporating arc extinguishing media to quickly extinguish the arc, thereby using smaller and cheaper pyrotechnic actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large pyrotechnic actuators are used to break thicker conductors for high current applications, then the conductor breaking capability is improved, but the switch size and cost increase
Solution Approach 1:
The continuous conductor is divided into three separate conductor pieces that are joined only temporarily by the breakable retaining member. This segmentation allows the conductors to be separated more easily, requiring significantly smaller forces to open the circuit compared to breaking a single thick continuous conductor, thus enabling smaller pyrotechnic actuators and reduced switch size
Solution Approach 2:
The breakable retaining member pre-assembles the three conductor pieces into a continuous current path before operation. This preliminary assembly creates a temporary joint that can be quickly broken by minimal force, eliminating the need for large actuators while maintaining high current carrying capability during normal operation
2Strength
If large pyrotechnic actuators are used to break thicker conductors, then the conductor breaking capability is improved, but the manufacturing cost increases
Solution Approach 1:
Dividing the conductor into separate pieces that join temporarily reduces the force requirements for circuit opening, allowing the use of smaller, less expensive pyrotechnic actuators. This segmentation strategy directly reduces component costs while maintaining the ability to handle high current applications
Solution Approach 2:
The breakable retaining member is designed as a disposable component that is broken during normal operation to open the circuit. This sacrificial component approach eliminates the need for expensive, large-capacity actuators, as the retaining member itself performs the function of enabling conductor separation at low cost
3Speed
If the third conductor moves from first position to second position upon pyrotechnic actuator ignition, then the current conduction path opening speed is improved, but the arc interruption capability must be enhanced
Solution Approach 1:
Arc extinguishing media is extracted and positioned between the first and second conductors to specifically address the arc interruption function. This separate arc management system allows the third conductor to move quickly to open the circuit while the arc extinguishing media simultaneously suppresses any arcs that may form, handling the harmful effect independently
Solution Approach 2:
Arc extinguishing media acts as an intermediary substance between the conductors during the opening process. When the third conductor moves to separate the circuit, this media is positioned to intercept and extinguish any arcs that form, enabling fast opening speeds while protecting against arc-related harmful effects
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
This design enables smaller, cheaper switches capable of handling various current loads with improved arc interruption, reducing the risk of electrical arcs and enhancing safety and robustness.
Implementation Method 1
a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition
Implementation Method 2
the retaining member is arranged to break in dependence on actuation of the pyrotechnic actuator to allow movement of the third conductor
Implementation Method 3
a third conductor moveable in a direction from a first position towards a second position upon (i.e. in response to) actuation by the pyrotechnic actuator
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A switch for opening a current conduction path is provided. The switch comprises an ignition chamber and a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition. The switch comprises first and second conductors, each comprising connection contacts. In a first position, a third, moveable, conductor of the switch is arranged between, and in electrical and physical contact with, the first and second conductors to define a current conduction path; in a second position, the third conductor is arranged to be electrically and physically separate from the first and second conductors. The third conductor is moveable in a direction from the first position towards the second position in response to actuation by the pyrotechnic actuator. The switch comprises at least one breakable (optionally shearable) retaining member arranged to retain the third conductor in the first position until actuation of the pyrotechnic actuator. A vehicle comprising the switch, and a method of operating the switch, are also provided.