Spiral Coil Pipe for Bowden Cable Herniation
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Solution Overview
Problem
Bowden cables in snake-like robots and articulating instruments are prone to catastrophic permanent lateral plastic deformation, or kinking, due to overloading and axial loads during articulation, which affects their functionality and longevity.
Innovation Solution
The use of coil pipes with a spiral pattern and tensioning members, where the coil pipes are constructed from D-shaped or centerless ground wire to reduce herniation, and the coil pipes are spiraled along the segments to localize movement and reduce friction, thereby minimizing the need for sliding and binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If Bowden cables are used to transfer forces in articulating instruments, then force transmission capability is improved, but the cables are prone to catastrophic permanent lateral plastic deformation (kinking) under overloading and axial loads
Solution Approach 1:
The Bowden cable is segmented into multiple sections, each housed in its own coil pipe. The cable can be divided into multiple tensioning members, allowing localized failure or deformation in one section without compromising the entire cable system. This segmentation enables the cable to better absorb and distribute axial loads and overloading forces.
Solution Approach 2:
The coil pipe is formed into a spiral or helical configuration rather than a straight tube. This curved geometry allows the coil pipe to flex and accommodate axial compression forces without transmitting them directly to the tensioning member, thereby preventing kinking and lateral plastic deformation of the Bowden cable under compressive or overloading conditions.
2Adaptability or versatility
If multiple simultaneous articulations are enabled, then the articulation capability of the snake-like robot is improved, but the Bowden cables must traverse multiple tortuous paths increasing susceptibility to herniation
Solution Approach 1:
Each articulation segment has its own dedicated coil pipe housing the tensioning member, isolating the cable path for each degree of freedom. This prevents cables from interfering with each other during simultaneous articulations and reduces the complexity of the overall cable routing path.
Solution Approach 2:
The spiral configuration of the coil pipe naturally accommodates tortuous paths and bending required for multiple simultaneous articulations. The helical shape allows the cable to follow curved trajectories through multiple joints without creating sharp bends or stress concentration points that would lead to herniation.
3Ease of manufacture
If traditional straight coil pipes are used, then manufacturing simplicity is maintained, but sliding and binding occur during articulation causing friction and reduced flexibility
Solution Approach 1:
The coil pipe is formed into a spiral or helical shape rather than a straight tube. This curved geometry allows the coil pipe to flex and accommodate axial compression forces without transmitting them directly to the tensioning member, thereby preventing kinking and lateral plastic deformation of the Bowden cable under compressive or overloading conditions.
Data Source
AI summary
The present invention relates, generally, to the reduction or elimination of permanent and catastrophic herniations in Bowden cables or coil pipes in articulating devices or snake-like robots. More particularly, the present invention relates managing the coil pipes in a spiral pattern along the articulating device or snake-like robot to reduce or eliminate the necessity of the Bowden cables or coil pipes to slide along the length of the articulating device or snake-like robot. Reduction or elimination of the necessity for the Bowden cables or coil pipes to slide reduces or eliminates catastrophic herniations in articulating devices or snake-like robots undergoing one or more articulations.