Tape Measure Embedding for Deployable Structure Stability
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Solution Overview
Problem
Deployable structures in space, such as solar generators, face challenges with large surface mass and inertia due to rigid panels, and measuring tapes experience uncontrolled deployment and instability, requiring additional holding devices or oversized designs to maintain stability in orbital forces.
Innovation Solution
A retractable embedding method for measuring tapes involves a main tape measure and a secondary tape measure forming a triangulated structure with a mandrel, allowing controlled deployment and refolding, with rollers providing rotational freedom and optional heating for regulated deployment, optimizing storage volume and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid panels are used for deployable structures, then controlled kinematics is achieved, but surface mass and inertia increase
Solution Approach 1:
The patent replaces rigid panels with flexible membranes that are stretched and tensioned during deployment. The flexible membrane itself is lightweight, but gains structural rigidity through geometric configuration (triangulated structure) and tension forces, thereby achieving controlled kinematics without the mass penalty of rigid panels.
2Ease of manufacture
If measuring tapes are made monostable with natural deployment tendency, then deployment is simplified, but deployment becomes anarchic and uncontrolled
Solution Approach 1:
The patent uses bistable measuring tapes that can maintain two stable states (stored and deployed). The tapes remain in the stored state until a triggering mechanism releases them, at which point they snap to the deployed state. This dynamic switching between stable states provides both simplicity (no active control needed during deployment) and control (deployment occurs only when triggered).
Solution Approach 2:
The measuring tapes are pre-configured in the stored position on the mandrel, ready for deployment. The triangulated structure is pre-assembled with the tapes attached to specific points on the mandrel and the flexible membrane, so that when deployment is triggered, the entire structure unfolds in a controlled sequence without requiring real-time adjustments.
3Speed
If tape measures are deployed simultaneously along entire length, then deployment speed is maximized, but shock and damage risk increase
Solution Approach 1:
The patent divides the deployment process into segments by using multiple measuring tapes (first and second tapes) that are attached at different points on the mandrel. The tapes can deploy in a staggered sequence, with one tape deploying before the other, thereby distributing the shock loads and preventing simultaneous straightening of the entire structure.
Solution Approach 2:
The bistable nature of the measuring tapes allows for controlled deployment timing. The tapes remain in the stored state until a triggering mechanism releases them, at which point they snap to the deployed state. This dynamic switching between stable states provides both simplicity (no active control needed during deployment) and control (deployment occurs only when triggered).
4Volume of moving object
If tape measure winding radius is minimized for compact storage, then storage volume is optimized, but deployment control and stability are reduced
Solution Approach 1:
The patent uses a triangulated structure that extends in multiple dimensions. The measuring tapes are attached to the mandrel at different radial positions and at different heights (Z-axis positions), creating a three-dimensional deployment pattern. This allows the tapes to be wound tightly on the mandrel for compact storage while maintaining adequate deployment control through the geometric configuration of the triangulated structure.
5Stability of the object's composition
If additional holding devices are added to maintain tape stability, then deployed state stability is improved, but device complexity increases
Solution Approach 1:
Instead of adding holding devices to prevent the tapes from collapsing, the patent inverts the approach by using the tapes themselves to create the stable structure. The triangulated configuration of the tapes, combined with the tension in the flexible membrane, creates inherent geometric stability that maintains the deployed state without requiring additional active holding mechanisms.
Solution Approach 2:
The measuring tapes are designed to be self-supporting through their triangulated configuration. Once deployed, the geometric arrangement of the tapes and the tension in the flexible membrane create a self-stabilizing structure that maintains its shape without requiring additional holding devices. The structure supports itself through its own configuration and internal forces.
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 method enables compact storage, controlled deployment, and enhanced stability of deployable structures by forming a triangulated structure with the mandrel, reducing the risk of damage during deployment and maintaining structural integrity in space.
Implementation Method 1
a first end of the secondary measuring tape is fixed at a distance from a second end of the main measuring tape, fixing a second end of the secondary measuring tape on the mandrel
Implementation Method 2
rollers providing rotational freedom and optional heating for regulated deployment
Implementation Method 3
optional heating for regulated deployment
Data Source
Figure 1a~1c
Figure 2~3
Figure 4
AI summary
The invention relates to a method for retractable insertion of a tape measure for a deployable structure. The method for retractable tape measure housing for a deployable structure, comprising a main tape measure (11) having a deployment and retraction axis substantially parallel to an unfolded axis X and having two ends (81, 82), a secondary tape measure (61) having two ends (71, 72) and a winding mandrel (13) carried by a shaft (14) parallel to an axis Z perpendicular to the axis X, the main tape measure (11) being wound around the mandrel (13), a first end (82) of the main tape measure (11) being fixed to the mandrel (13) comprises the following steps: • Fixing a first end (71) of the secondary tape measure (61) at a predetermined distance from a second end (81) of the main tape measure (11), • Fixing a second end (72) of the secondary tape measure (61) on the chuck (13).The invention also relates to a deployable structure comprising a tape measure for a flexible structure.