Foldable Scissor Module for Doubly Curved Deployable Grids
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Solution Overview
Problem
Existing scissor grids face challenges in achieving geometric compatibility throughout all deployment stages, leading to inefficient deployment and locking processes, especially in large structures, where manual locking is time-consuming and difficult due to the need for multiple locking devices.
Innovation Solution
A foldable scissor module comprising at least four polar scissor units with non-identical rod lengths and semi-lengths, where the unit lines are not concurrent, ensuring fixed internal dihedral angles and symmetry, allowing for geometric compatibility in all deployment stages without the need for external locking devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional scissor grids use multiple locking devices to maintain stability during deployment, then structural stability is improved, but the complexity of the deployment process and time consumption increase
Solution Approach 1:
The scissor module is designed to automatically lock and unlock during deployment through its inherent geometric compatibility. The mechanism uses its own structural configuration - specifically the fixed internal dihedral angles and the arrangement of polar scissor units with non-identical rod lengths - to self-stabilize at deployment stages without requiring external locking devices, thereby simplifying the deployment process while maintaining stability
2Ease of manufacture
If scissor grids use regular basic polar units with identical rod lengths, then manufacturing simplicity is improved, but the ability to achieve geometric compatibility throughout all deployment stages deteriorates
Solution Approach 1:
The invention introduces asymmetry by using polar scissor units with non-identical rod lengths and semi-lengths. This asymmetric configuration is essential for achieving fixed internal dihedral angles and geometric compatibility throughout all deployment stages. The asymmetry in rod lengths allows the unit lines to be non-concurrent, which is the key geometric feature that enables the module to maintain structural integrity and compatibility during deployment
3Stability of the object's composition
If manual locking devices are used in large scissor grid structures, then structural stability is improved, but the time and labor required for locking increase
Solution Approach 1:
The scissor module automatically achieves stability through its geometrically compatible design. The fixed internal dihedral angles and the specific configuration of polar scissor units with non-identical rod lengths enable the structure to self-lock during deployment, eliminating the need for manual locking operations and significantly reducing the time and labor required for large-scale structures
4Reliability
If scissor modules use non-identical rod lengths and non-concurrent unit lines, then geometric compatibility is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention deliberately employs asymmetric polar scissor units with non-identical rod lengths and non-concurrent unit lines. While this increases manufacturing precision requirements, it is necessary to achieve the fixed internal dihedral angles and geometric compatibility throughout all deployment stages. The asymmetric design is the fundamental enabler of the module's self-locking capability and structural integrity
Data Source
Figure 1a
Figure 1b
Figure 2a~2b
AI summary
The invention is related to a foldable scissor module formed of polar scissor units and comprising at least four polar scissor units characterized in that: • At least one of the polar scissor units consists of rods that are not identical in terms of their length and/or their semilengths, i.e. at least one unit is not a regular basic polar (PRB) unit, • The unit lines of the polar units are not all concurrent. The major advantage of the new foldable modules according to the invention is that they generate deployable scissor grids with 'freeform' double curvature using straight bars (existing concepts using straight bars mostly have no, single or spherical double curvature).