Adjustable Actuator Stroke Limits to Prevent Aerospace Over-Travel Damage

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Solution Overview

Problem

Existing actuators often have excess capacity under normal conditions, leading to potential damage to system components when they fail to extend or retract to their maximum travel distance due to insufficient design robustness or travel distance accommodation.

Innovation Solution

A stroke limiting device for aerospace actuators that adjusts the stroke limits manually or automatically through adjustable engagement units, including threaded configurations or electromechanical motors, to prevent undue load on system components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If actuators are designed with excess capacity to ensure sufficient power, then the actuator can handle worst-case conditions, but the actuator may damage system components when failing to extend or retract fully due to insufficient travel distance accommodation

Engineering Contradiction:
Improveactuator reliabilityVSAvoidcomponent damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the actuator stroke limits adjustable rather than fixed. The stroke limiting device includes adjustable engagement units that allow the retraction and extension limits to be modified based on specific system requirements, enabling the actuator to adapt its travel distance dynamically to prevent component damage while maintaining sufficient power capacity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of stroke length from a fixed design value to an adjustable parameter. By incorporating adjustment mechanisms (threaded adjustments or electromechanical motors), the actuator's travel distance can be modified to match the actual system capacity, preventing over-travel damage while preserving the actuator's power capability

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If actuators are designed with fixed stroke limits, then the manufacturing and installation process is simplified, but the actuator cannot be adjusted to match varying system requirements, leading to either excess capacity or insufficient protection

Engineering Contradiction:
Improveactuator manufacturing easeVSAvoidactuator adaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static stroke limiting structure into a dynamic, adjustable one. The engagement units with adjustment mechanisms allow the actuator to be configured for different stroke lengths depending on the specific application, maintaining manufacturing simplicity while significantly improving adaptability to various system requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent makes the actuator universal by enabling it to serve multiple different system configurations through adjustable stroke limits. The same actuator model can be adapted to different travel distance requirements by modifying the engagement unit settings, eliminating the need for multiple fixed-stroke actuator variants

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

Data Source

PatentEP4607038A1Aerospace actuator stroke limiting device
Publication Date: 2025.08.27 PRATT & WHITNEY CANADA CORP
  • EP4607038A1 patent drawingFigure 1
  • EP4607038A1 patent drawingFigure 2~3
  • EP4607038A1 patent drawingFigure 4

AI summary

An aerospace actuator (101; 401) is provided and includes an actuator housing (110; 410), second and third parts (120; 130; 420; 430) respectively including retraction-limiting and extension-limiting surfaces (121; 131; 421; 431), a piston (140; 440) and a stroke limiting device (150; 450). The piston (140; 440) is movable within the actuator housing (110; 410) between a retraction-limited position where the piston (140; 440) impinges against the retraction-limiting surface (121; 421) and an extension-limited position where the piston (140; 440) impinges against the extension-limiting surface (131; 431). The stroke limiting device (150; 450) includes at least one of a first adjustable engagement unit (151; 451) and a second adjustable engagement unit (152; 452). The first adjustable engagement unit (151; 451) is disposed between the actuator housing (110; 410) and the second part (120; 420) for adjusting a first distance (D1; D11) between the actuator housing (110; 410) and the retraction-limiting surface (121; 421). The second adjustable engagement unit (152; 452) is disposed between the second part (120; 420) and the third part (130; 430) for adjusting a second distance (D2; D22) between the extension-limiting surface (131; 431) and the retraction-limiting surface (121; 421).