Independent-Drive Locking Mechanism for Fracture-Tolerant Hooks
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Solution Overview
Problem
Conventional S-shaped locking mechanisms fail if the locking member fractures between the actuator attachment and pivot, leading to a loss of locking function for both hooks, which is critical in safety applications like aircraft engines.
Innovation Solution
The locking mechanism employs a coupling system with independent drive couplings and angled slots to allow disengagement of fractured arms, ensuring that the actuator can still drive the other locking arm, maintaining partial locking functionality and preventing adverse loading on the actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the locking member is constructed as a single S-shaped component with both hooks rigidly connected, then the structure is simple and reliable under normal conditions, but a fracture in one arm disables the entire mechanism
Solution Approach 1:
The locking member is divided into two separate locking arms (first locking arm and second locking arm) that are independently pivotable about the same pivot. Each arm has its own hook that can independently engage with corresponding catches. This segmentation allows one arm to remain functional even if the other arm fractures or fails, thereby improving reliability while maintaining relatively simple structure.
2Stability of the object's composition
If the actuator is rigidly connected to both hooks of the S-shaped locking member, then the locking action is synchronized, but a fracture between the actuator attachment and pivot prevents actuating movement
Solution Approach 1:
The connection between the actuator and the locking arms is segmented through independent mounting arrangements. The actuator is hinged to both the first and second locking arms separately, allowing each arm to be actuated independently. This enables the system to maintain partial actuating capability even if one arm fractures, while still achieving synchronized locking through coordinated actuation of both arms.
Solution Approach 2:
The connection parameters between the actuator and locking arms are changed from rigid fixed connections to hinged connections with controlled degrees of freedom. This allows the locking arms to pivot independently about their respective hinge points while still being driven by the actuator, providing both synchronization and fracture tolerance.
3Strength
If a fracture occurs in the locking member arm, then the structure fails, but the actuator continues to bear load causing adverse loading
Solution Approach 1:
The hinged connection between the actuator and locking arms provides a built-in failure mode that prevents adverse loading. If a locking arm fractures, the hinge allows the arm to disconnect or become limp without transmitting harmful loads back to the actuator. This beforehand cushioning through the hinge design protects the actuator from damage even when structural integrity of one arm is compromised.
Data Source
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AI summary
A locking mechanism (2) comprises an S-shaped locking member (4) which comprises respective locking hooks (6a, 6b) arranged at the end of opposed arms (8a, 8b) of the locking member (2). A pivot (10) is arranged between the arms (8a, 8b) of the locking member (4). The locking member rotates around the axis (A) of the pivot (10). The locking mechanism (2) further comprises a coupling (24) for coupling the locking member (4) to an actuator (16) for rotating the locking member (4) around the pivot axis (A). The coupling (24) comprises at least one coupling element (30, 32), an actuator coupling (58) for coupling the at last one coupling element (32) to the actuator (16) and first and second drive couplings (70, 72) for coupling the at least one coupling element (30, 32) independently to each arm (8a, 8b) of the locking member (4) for transmitting rotational movement thereto, such that failure of one arm (8a) of the locking member (4) will not cause loss of drive to the other arm (8b) of the locking member (4).