Clevis-Sensing Lock Mechanism Prevents Mislocked Aircraft Latches
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Solution Overview
Problem
Aircraft latch mechanisms can be mislocked, appearing closed but not fully engaged, which poses a risk during flight and maintenance, as they may inadvertently unlock, leading to safety issues and damage.
Innovation Solution
A clevis-sensing lock mechanism that ensures the latch is fully closed and locked by using a key or tool to unlock and open the latch, with a mechanism that retains the key until the latch is in the proper closed position and includes a visual indicator for confirmation, preventing accidental opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional latch mechanism is used, then the latch can be operated easily, but the latch may appear closed without being fully engaged, leading to unreliable locking
Solution Approach 1:
A key-operated lock mechanism serves as an intermediary between the operator and the latch. The lock includes a key cylinder, tumblers, and a locking bar that must be manipulated with a key to release the latch. This intermediary mechanism ensures that only when the proper key is used and the latch is fully engaged can the locking bar be repositioned to allow key removal, thereby guaranteeing reliable locking while maintaining a relatively simple overall structure.
2Object-affected harmful factors
If the latch is clipped to a lower profile position, then the latch is protected from damage, but the latch cannot be distinguished from a locked state
Solution Approach 1:
A visual indicator component is incorporated into the latch mechanism that changes its visible state based on the locking condition. When the latch is locked, the indicator displays one state (such as a visible flag in a specific position or a colored indicator). When unlocked or in the clipped position, the indicator displays a different state. This allows the latch to maintain a low profile for protection while providing clear visual information about its locking state.
3Ease of operation
If the latch is allowed to operate freely, then the operation is simple, but the latch may inadvertently unlock during operation
Solution Approach 1:
The lock mechanism requires preliminary action with a key before the latch can be operated. The key must be inserted into the key cylinder and turned to a specific position to retract the locking bar, which then allows the latch to move. This preliminary key operation ensures that the latch cannot be accidentally activated, as the key must be deliberately manipulated first. Once the key is removed, the locking bar prevents any further operation, maintaining reliability while keeping the actual latch movement simple.
Data Source
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AI summary
A lock mechanism (50) comprises a block (64) having a first bore (154) extending into the block and a pin-receiving slot (192) extending into the block to intersect therewith. A lock cylinder (102) is receivable in the first bore and moveable relative to the block. The lock cylinder includes first and second ends, an annular groove (158), an axial slot (180) extending toward the first end from the groove, and a second bore (92) extending from the second end toward the first end. A cross-pin (114) is configured to slide in the annular groove and axial slot to control lock cylinder movement. A tumbler arrangement (66) is coupled between the lock cylinder and the block and can control lock cylinder movement. A coupler shaft (68) is positioned within the second bore and coupled with the lock cylinder to move therewith. An interference member (56) is coupled to the coupler shaft at the first end of the lock cylinder to move therewith.