Ram Air Turbine Actuator Lock Bolt Reducing Release Force

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Solution Overview

Problem

Existing ram air turbine deployment systems face challenges in deploying the actuator with limited electrical power and high loads during emergency situations, as typical up-lock and down-lock mechanisms require significant force due to high door loads generated by aircraft flight conditions.

Innovation Solution

The actuator design incorporates a lock bolt with radially supported rollers and chamfers, which reduce the release force required by distributing loads evenly and allowing axial movement, enabling efficient deployment of the ram air turbine even under high load conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional locking mechanisms with locking wedges are used, then the actuator can be restrained in stowed and deployed positions, but the release force required becomes excessively high under emergency flight conditions

Engineering Contradiction:
Improvelocking reliabilityVSAvoidrelease force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

A lock bolt is introduced as an intermediary component between the locking wedges and the actuator cylinder. The lock bolt engages with grooves in the locking wedges and translates their radial locking force into axial restraint force, enabling effective locking with reduced release force requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional direct wedge-locking mechanism is replaced with a bolted locking system. The lock bolt with threaded engagement provides mechanical advantage through screw mechanics, allowing the locking wedges to maintain secure locking with significantly lower actuation force compared to direct wedge movement

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

2Reliability

If four locking wedges are used to ensure reliable locking, then the actuator can be securely restrained, but the complexity of the locking mechanism increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple locking functions are merged into a single integrated lock bolt component. The lock bolt simultaneously engages with multiple locking wedges, providing unified control of the locking and release operations while maintaining the reliability of multiple wedge contacts

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lock bolt serves multiple functions: it engages with the locking wedges to translate radial forces to axial restraint, provides a centralized release mechanism, and maintains the structural integrity of the locking system. This multi-functionality reduces the need for separate components for each locking wedge

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances the capacity of the actuator to deploy the ram air turbine with reduced release force, ensuring reliable power generation in emergency situations by effectively managing high loads and limited electrical power availability.

Implementation Method 1

Multiple rollers are supported in the lock bolt and are configured to radially support the up-lock wedges in a retracted position

Methodology Applied
Scientific EffectRolling contact: Roller

Implementation Method 2

rollers include chamfers engaging one another

Methodology Applied
Scientific EffectFriction reduction: Friction

Implementation Method 3

The rollers include chamfers engaging one another

Methodology Applied
Scientific EffectChamfer engagement: Geometry

Data Source

PatentEP2527664B1Ram air turbine deployment actuator having locking means
Publication Date: 2018.11.21 HAMILTON SUNDSTRAND CORP
  • EP2527664B1 patent drawingFigure 1
  • EP2527664B1 patent drawingFigure 2~3
  • EP2527664B1 patent drawingFigure 4A~5

AI summary

An actuator (24) for a ram air turbine system (10) includes a lock bolt (52) having a multiple circumferentially arranged lateral supports (78). A piston rod (42) supports multiple up-lock wedges (48). Multiple rollers (76) are supported by the lateral supports with chamfers (96) on the rollers engaging one another and are configured to radially support the up-lock wedges in a retracted position.