Redundant Locking Cam for Helicopter Load Hook Release
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Solution Overview
Problem
Existing load hooks for helicopters lack redundancy in locking mechanisms, making them vulnerable to accidental opening during flight due to external load oscillations, which can lead to safety issues during emergency situations like engine loss.
Innovation Solution
A cam-based locking mechanism with a central hub and a cylindrical hollow shaft, actuated by independent electrical and hydraulic control systems, providing multiple redundant release options to ensure safe load handling and minimize accidental opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single control mechanism is used to actuate the locking cam, then the device complexity is reduced, but the reliability of the locking mechanism is insufficient due to lack of redundancy
Solution Approach 1:
The control mechanism is segmented into two independent control systems (first and second controls) that can independently actuate the locking cam. This segmentation provides redundancy while maintaining manageable complexity through modular design.
Solution Approach 2:
The system changes the control parameter from a single control input to multiple independent control inputs, thereby improving reliability through redundancy while the modular architecture prevents excessive complexity increase.
2Productivity
If the hook is suspended some distance below the helicopter, then the load can be transported, but oscillations are induced that can cause unintended opening of the hook
Solution Approach 1:
The locking mechanism is designed with redundant controls and a robust cam-based locking system that anticipates and resists the harmful oscillations before they can cause unintended opening, providing a safety buffer against pendulum-induced stresses.
Solution Approach 2:
The locking cam and lever mechanism create a preliminary anti-action force that counteracts the oscillation-induced stresses on the hook, preventing unintended opening while maintaining load transport capability.
3Reliability
If a ratchet mechanism is used to lock the hook in the closed position, then the hook can be locked during flight, but rapid load release requires additional electrical release mechanisms
Solution Approach 1:
The locking cam mechanism serves multiple functions: it provides the locking action during flight and also enables rapid release when actuated by either control system. This multi-functionality reduces the need for separate release mechanisms while maintaining reliability.
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 solution provides a safe and reliable mechanism for locking and unlocking the load hook, capable of supporting loads from 5 kg to 10 tonnes without accidental opening, enhancing aviation safety by offering multiple independent control means for load release.
Implementation Method 1
The shaft is returned to position by a tension spring mounted between the transmission element and a rod attached to a frame
Implementation Method 2
in which the central hub is returned to position by a torsion spring mounted between said central hub and said rod
Data Source
Figure 1a~1b
Figure 2~4
Figure 5~8
AI summary
The invention relates to a cam (43) for locking and unlocking a hook (10) of an attachment device (100) intended to lift and transport loads, having a central hub (430), at least one arm (431a) arranged radially relative to the central hub and a shaft (435) rotating the central hub, characterised in that a first end of the shaft (425) is connected to a first rotational device (51) and a second end of the shaft is connected to a second rotational device (52). The invention also relates to an attachment device comprising such a cam.