Articulated Joint With Progressive Spring for Smooth Solar Array Deployment
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Solution Overview
Problem
Existing joints for deploying and locking solar generators or reflectors in space experience high material stress due to uneven unfolding moments, particularly at the beginning and end of deployment, and are prone to sudden locking issues caused by frictional torques from electrical cabling.
Innovation Solution
A joint with two halves and a drive spring featuring a progressive spring characteristic that increases over the unfolding angle to compensate for varying friction torque, ensuring a consistent and sufficient unfolding moment throughout the deployment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a constant torque spring is used to provide uniform unfolding moment, then system components are relieved and disturbing torques are reduced, but frictional torques from electrical cabling cannot be compensated and sudden locking may still occur
Solution Approach 1:
The patent changes the torque parameter from constant to progressive by using a drive spring with progressively increasing spring constant. This allows the unfolding moment to increase with deployment angle, compensating for the increasing frictional torques from electrical cabling and ensuring reliable completion of the deployment process without sudden locking.
2Reliability
If higher unfolding moment is provided at the end position to ensure locking, then the joint bearing is under constant contact pressure ensuring play-free operation, but material stress on components increases significantly
Solution Approach 1:
The patent applies a progressive spring characteristic where the drive spring constant increases with the deployment angle. This dynamic adjustment provides higher unfolding moments at the end position to ensure reliable locking and play-free operation, while keeping the moment lower during intermediate stages to reduce material stress on components.
3Device complexity
If frictional torques are not compensated, then the joint structure remains simple, but the unfolding process may be interrupted by sudden locking due to insufficient torque
Solution Approach 1:
The patent uses a drive spring with a progressive spring characteristic where the spring constant increases with deployment angle. This simple parameter change in the spring design automatically compensates for increasing frictional torques from electrical cabling during deployment, ensuring reliable completion without adding complex control mechanisms.
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
This design reduces material stress on components, provides a stable unfolding mechanism, and can handle higher frictional torques, ensuring a smooth deployment and locking process without excessive stress or sudden stops.
Implementation Method 1
a drive spring (1) having a progressive spring characteristic which increases over the unfolding angle
Implementation Method 2
The drive spring (1) is arranged on a drive roller (7), with a fixed end of the drive spring (1) being firmly connected to the drive roller (7)
Implementation Method 3
frictional torques that occur during the unfolding cannot be taken into account and compensated for. The friction torque results from the electrical lines of the solar generator or reflector
Data Source
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AI summary
The invention relates to an articulated joint for deploying and locking a solar generator or a reflector or another deployable space travel component is proposed, which consists of two joint halves (4, 10), a joint axle, and a drive. A driving spring (1) of the drive has a spring characteristic line across the unfolding angle of the two joint halves (4, 10), which progressively increases during the deployment, in order to compensate for the friction moment which varies across the unfolding angle.