Cargo Hook Cam Latch Mechanism Against Load-Induced Opening
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Solution Overview
Problem
Existing cargo hook systems for helicopters face issues with accidental opening due to weight-induced stress and low torque reduction ratios, leading to safety concerns during load transport.
Innovation Solution
A load-bearing device with a pivotally mounted hook, a latch and release mechanism featuring rollers and a locking cam, which provides a tilting lever mechanism to securely lock and release the hook, utilizing electric or hydraulic controls for safe operation, and incorporating a safety pawl for enhanced redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism with bearings is used to hold the hook in the closed position, then the hook can be secured during flight, but the bearings can be easily overcome by the weight of the lifted loads causing accidental opening
Solution Approach 1:
The patent replaces the traditional bearing-based locking mechanism with a cam-based mechanical advantage system. The cam mechanism transforms the locking action from a bearing-supported lever system to a cam-profile-driven system where the cam's geometric shape provides the locking force, eliminating the need for bearings at the locking interface and preventing bearing failure under load.
Solution Approach 2:
The patent changes the mechanical parameters of the locking system by introducing a cam with specific profile geometry that provides high mechanical advantage. This allows a small actuating force to generate a large locking force, increasing the system's resistance to load-induced opening while maintaining reliable locking during flight.
2Device complexity
If a simple locking mechanism is used, then the device complexity is reduced, but the torque reduction ratio is very low making it impossible to reduce the effort required for opening the hook
Solution Approach 1:
The patent substitutes a simple locking mechanism with a cam-based system that inherently provides torque multiplication through its geometric profile. The cam's shape creates a mechanical advantage that reduces the actuating force needed to open the hook, while the overall mechanism remains relatively simple with fewer moving parts than traditional bearing-based systems.
3Adaptability or versatility
If the hook is suspended at a distance below the helicopter to form a pendulum system, then the helicopter can transport external cargo, but the oscillations induced in the externally attached cargo can result in significant stresses in the hook and cause it to be unintentionally opened
Solution Approach 1:
The patent changes the mechanical parameters of the locking system by introducing a cam mechanism with high mechanical advantage, which increases the force required to open the hook. This heightened locking force provides a safety margin that prevents unintentional opening even when oscillations from pendulum motion transmit stresses to the hook during cargo transport.
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 device ensures secure locking and controlled release of loads up to 10 tons without untimely opening, minimizing the risk of accidental hook activation during flight, with redundant control mechanisms for enhanced safety.
Implementation Method 1
a first roller at a first end and a second roller at a second end opposite the first end, in that the latch comprises an upper cavity in which the first roller can rest and roll
Implementation Method 2
the locking cam is provided with at least one locking arm on which the second roller can rest and roll
Implementation Method 3
rotation of the locking cam in one direction produces a tilting of the lever in the other direction, releasing the first roller from the latch
Implementation Method 4
pivoting the latch under the effect of the hook until the end of said hook is released from the lower cavity of said latch
Data Source
AI summary
A bearing device comprising a hook, housing, and latch and release mechanism for locking and unlocking the hook, the lock and release mechanism having a pivot latch with a lower cavity capable of receiving one end of the hook, a lever and a locking cam. The lever is pivotally mounted in the housing and has first roller and second rollers on the ends thereof, the latch has an upper cavity in which the first roller can rest and roll, the cam has at least one locking arm on which the second roller can rest and roll. A rotation of the cam in one direction causes the lever to tilt in the other direction, releasing the first roller from the latch, and causes the latch to pivot under the weight of the hook until the end of the hook is released from the lower cavity in the latch.