Pyrotechnic Actuator Piston Calibrated Venting

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Solution Overview

Problem

Existing pyrotechnic actuators for emergency opening devices in buildings and vehicles, such as aircraft, face issues like leakage in pneumatic and hydraulic systems and violent operation in pyrotechnic actuators, leading to safety concerns and potential damage.

Innovation Solution

A pyrotechnic actuator with a cylindrical body and a piston that includes a pyrotechnic gas generator, featuring calibrated vents for gas passage between chambers, a larger surface area on one piston face for progressive force application, and removable securing means for controlled operation, allowing for progressive and timed action without violent activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If pyrotechnic actuators are used for emergency opening devices, then rapid actuation is achieved, but violent operation occurs leading to destruction of the opening door

Engineering Contradiction:
Improveactuation speedVSAvoidviolent operation damage
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The actuator is divided into two chambers separated by a piston, with the pyrotechnic generator in the first chamber and the second chamber receiving gas through calibrated vents. This segmentation allows controlled progressive expansion rather than direct violent force transmission to the door.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The calibrated vents act as an intermediary element between the pyrotechnic gas generator and the second chamber, regulating the gas flow and preventing direct violent transmission of force to the door while maintaining rapid actuation capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If pneumatic or hydraulic cylinders are used, then controlled progressive action is achieved, but leakage problems occur requiring special monitoring and maintenance

Engineering Contradiction:
Improvecontrolled operationVSAvoidleakage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical pneumatic or hydraulic fluid systems with a pyrotechnic gas generation system. The gas is generated on-demand by the pyrotechnic initiator, eliminating the need for fluid storage, pressure maintenance, and leakage prevention associated with traditional pneumatic/hydraulic systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the state of the working medium from stored compressed fluid to generated gas. The pyrotechnic generator creates gas at controlled rates through calibrated vents, transforming the parameter control from mechanical pressure regulation to chemical reaction rate control.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If pneumatic or hydraulic cylinders are used, then fluid storage and pressure maintenance are required, but this constitutes a disadvantage for maintenance and safety

Engineering Contradiction:
Improveactuation controlVSAvoidfluid storage and pressure system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and removes the complex fluid storage and pressure maintenance subsystems from the actuator. Instead of storing pre-compressed fluid under pressure, the system uses a compact pyrotechnic generator that creates gas on-demand, eliminating tanks, pressure regulators, and associated safety systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pyrotechnic generator acts as a disposable single-use component that replaces complex reusable fluid storage systems. After one use, the generator is consumed, but this simplicity in structure compensates for the single-use nature, reducing overall system complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution provides a safe, controlled, and progressive effort for actuating doors, enabling repositioning of the cylinder rod after use and ensuring reliable operation with adjustable timing and reduced risk of damage.

Implementation Method 1

a pyrotechnic gas generator (4)

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

the piston comprises at least one vent (11) allowing the calibrated passage of the gas generated by the generator (4) between the two chambers (A, B)

Methodology Applied
Scientific EffectGas flow through calibrated opening:

Implementation Method 3

a compression spring (18) interposed between a cap (8) of the cylinder body (1) and the piston (5)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2166233B1Gradual action jack
Publication Date: 2013.03.27 NEXTER MUNITIONS SA
  • EP2166233B1 patent drawingFigure 1a
  • EP2166233B1 patent drawingFigure 2
  • EP2166233B1 patent drawingFigure 3a~3b

AI summary

The jack has a rod (2) sliding in a cylindrical jack body (1) and integrated with a piston (5). The piston has two surfaces (SA, SB) contacted with two chambers (A, B), respectively, where the piston delimits the chambers. The piston comprises a vent hole (11) for allowing a calibrated passage of gas generated by a pyrotechnic gas generator (4) between the chambers. The piston comprises borings (12) for passing the gas between the generator and one of the chambers. A compression spring is interposed between a cap (9) of the body and the piston.