Removable Locking Device for Electric Thrust Reverser Actuator
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Solution Overview
Problem
Existing electric thrust reversers for aircraft require a permanently mounted manual drive unit and intermediate locking device, leading to increased mass, cost, and system inertia during maintenance, which complicates maintenance and is inefficient.
Innovation Solution
A removable locking device and torque limiting mechanism using a drive spline with a hollow shaft and a correspondingly contoured shaft for the locking device, allowing for reversible functionality to prevent movement and control torque without being permanently mounted, thus reducing system mass and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanently mounted manual drive unit and intermediate locking device are used, then the thrust reverser can be locked during maintenance, but the system mass and inertia increase
Solution Approach 1:
The locking device is extracted from a permanently mounted intermediate configuration and converted into a removable component that can be inserted into the drive spline hollow shaft only when needed for maintenance locking, thereby eliminating the permanent mass addition while preserving the locking capability
Solution Approach 2:
The locking function is segmented into a separate removable locking device that can be independently inserted into or removed from the drive spline, allowing the locking capability to be activated only when required rather than being permanently integrated into the system
2Reliability
If a permanently mounted intermediate locking device is used, then the actuator can be locked, but the device complexity and cost increase
Solution Approach 1:
The intermediate locking device is extracted from the permanent system architecture and replaced with a removable locking means that interfaces directly with the drive spline hollow shaft, simplifying the overall device structure while maintaining the locking function
Solution Approach 2:
The drive spline hollow shaft serves multiple functions: it transmits rotational motion during normal operation and simultaneously provides a receptacle for the removable locking device during maintenance, eliminating the need for a separate intermediate locking structure
3Weight of moving object
If a removable locking device is used, then the system mass is reduced, but the locking reliability may be compromised
Solution Approach 1:
The removable locking device is nested within the drive spline hollow shaft, where the locking means shaft is received and retained within the hollow shaft structure, providing a secure mechanical interference fit that ensures reliable locking without permanent system modification
Solution Approach 2:
The locking device features an asymmetric design where the shaft outer surface contours are specifically shaped to mate with corresponding internal features of the hollow shaft, creating a secure mechanical engagement that prevents accidental disengagement while maintaining removability
Data Source
AI summary
A thrust reverser is described that comprises a new type of locking means for locking an actuator in position so that maintenance can be performed on the machine. The locking means comprises a removable locking device for preventing movement of an actuator. The locking means may also function in one configuration as an end cap. An actuator is also described comprising a removable torque limiting device for limiting torque of the actuator.