Aircraft Decompression Panel Latch With Constant-Moment Slip Joint
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Solution Overview
Problem
Existing latch assemblies for aircraft decompression panels are triggered by normal relative motion between the panel and aircraft structure, leading to inconsistent force requirements for activation and potential unnecessary opening.
Innovation Solution
A latch assembly with a swing arm and load pin configuration that functions as a slip joint, using a spring with a fixed end and floating end to maintain a constant moment arm, and includes features like a shim and cam profile to ensure accurate and consistent triggering force despite relative motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the latch assembly uses a fixed connection between the load pin and the panel, then the relative motion is eliminated, but the complexity of the latch assembly increases and the spring force becomes dependent on bend geometry that may relax over time
Solution Approach 1:
The patent applies the dynamics principle by making the load pin movable within the slot of the bracket instead of fixed. This allows the load pin to accommodate relative motion between the panel and aircraft structure while maintaining a constant moment arm distance from the hinge axis. The dynamic positioning ensures consistent triggering force without requiring complex fixed connection mechanisms or relying on bend geometry that may relax over time.
2Ease of manufacture
If the latch assembly allows relative motion between the panel and aircraft structure, then the simplicity of installation is maintained, but the triggering force becomes inconsistent and may be triggered by normal turbulence
Solution Approach 1:
The patent uses the load pin as an intermediary element between the bracket and the swing arm. The load pin moves within the slot of the bracket, serving as a mediator that accommodates relative motion while maintaining a constant moment arm. This intermediary mechanism allows installation simplicity to be maintained while ensuring triggering force consistency by preventing the load pin from being directly affected by turbulent movements.
3Adaptability or versatility
If the moment arm distance varies due to relative motion, then the latch assembly adapts to turbulence, but the triggering force becomes inconsistent
Solution Approach 1:
The patent applies dynamics by allowing the load pin to move dynamically within the bracket's slot while maintaining a constant moment arm distance from the hinge axis. This dynamic positioning ensures that the load pin can accommodate relative motion between the panel and aircraft structure without varying the moment arm, thereby maintaining consistent triggering force while adapting to turbulence.
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
The assembly reliably activates at a predetermined pressure differential without being triggered by normal aircraft turbulence, ensuring consistent and accurate decompression panel opening.
Implementation Method 1
A spring is secured to the base and is positioned to exert a spring force against the swing arm when the swing arm pivots from the latched position to the unlatched position
Implementation Method 2
the load pin exits the open end of the slot when the swing arm pivots from the latched position to the unlatched position under a force of the bracket on the load pin due to a pressure differential on the decompression panel
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
A latch assembly (10) for a decompression panel (26) in an aircraft (12) includes a base (42) and a swing arm (44) hinged to the base (42) and pivotable relative to the base (42) about a hinge axis (46) between a latched position and an unlatched position. A load pin (40) fixed to the swing arm (44) has a pin axis (48) a fixed distance from the hinge axis (46). A spring (35) secured to the base (42) is positioned to exert a spring force against the swing arm (44) when the swing arm (44) pivots from the latched position to the unlatched position. A bracket (32) securable to the decompression panel (26) defines a slot (62) retaining the load pin (40) when the swing arm (44) is in the latched position. The load pin (40) is movable in the slot (62) under relative motion of the bracket (32) and the base (42) with the swing arm (44) in the latched position, and exits the slot (62) when the swing arm (44) pivots to the unlatched position.