Self-homing hoist hook assembly vibration damage prevention
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Solution Overview
Problem
Rescue hoists face damage due to system vibrations and aerodynamic loading when the hook assembly is not returned to its homed position, causing the cable to be unstressed and leading to premature wear of components.
Innovation Solution
A self-homing system with sensors and a controller that monitor conditions related to homing factors, compare them to threshold requirements, and activate the motor to reel the hook assembly into the homed position, ensuring the cable is tensioned and the hook assembly is securely positioned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hook assembly is manually returned to the homed position, then the cable is tensioned and the cable drum is held stationary, but this requires manual operation and may be overlooked
Solution Approach 1:
The hook assembly automatically returns to the homed position through self-homing mechanisms including sensors that detect cable tension and control systems that activate the motor to reel in the cable, eliminating the need for manual intervention
Solution Approach 2:
Sensors monitor cable tension and hook position, providing feedback to the control system which adjusts motor operation to ensure the hook assembly reaches and maintains the homed position with proper cable tension
2Device complexity
If the hook assembly is not returned to the homed position, then the system structure is simpler, but damage occurs due to system vibrations and aerodynamic loading
Solution Approach 1:
The system automatically detects when the hook assembly is not homed and initiates the homing sequence without requiring additional complex manual controls or monitoring systems
Solution Approach 2:
The homing sequence is automatically initiated based on detected conditions (such as aircraft movement or time since operation), ensuring the hook assembly is returned to the homed position before damage can occur from vibrations or aerodynamic loading
3Reliability
If sensors and control systems are added for automatic homing, then the hook assembly is reliably homed, but the device complexity increases
Solution Approach 1:
Existing system components such as the motor, cable drum, and control system are used for multiple functions including both operation and automatic homing, reducing the need for separate dedicated homing components
Solution Approach 2:
Simple sensors detect cable tension and hook position to provide feedback that triggers the homing sequence, using minimal sensing components to achieve reliable automatic homing
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A self-homing hoist includes a controller (38) configured to initiate a self-homing process to return the hook assembly (14) to a homed position in response to each of at least one homing factor being true. Each homing factor is true or false based on a comparison of the current condition, determined by a plurality of sensors (40), of the homing factor with a threshold requirement. If the current condition satisfies the threshold requirement, then the homing factor is true. If the current condition does not satisfy the threshold requirement, then the homing factor is false. Where all homing factors are true, the controller can initiate the self-homing process by activating a hoist motor (22) to drive the cable drum (26) and reel the hook assembly (14) into the homed position.