Cable Deflection Device with Arc-Shaped Support Zone
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Solution Overview
Problem
Traditional saddle designs for structural cables cause uneven stress distribution and damage to individually sheathed strands due to wedging forces, leading to potential corrosion protection weaknesses when used with cables that require special insulation measures.
Innovation Solution
A deflection device with ducts having a support zone with an arc-shaped section matching the strand's diameter, ensuring adequate friction and stress distribution, allowing uninterrupted plastic sheaths and compatibility with individually sheathed strands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a V-shaped conduit with wedging effect is used to block the strand, then the strand is prevented from sliding along the curved path, but the individual sheath of the strand is damaged and stress distribution becomes uneven
Solution Approach 1:
The conduit cross-section is designed with different geometries in different zones: a V-shaped blocking zone at the curved path location to prevent sliding, and a widened entrance zone to facilitate strand insertion without damage. This local differentiation resolves the contradiction between securing the strand and protecting the sheath.
Solution Approach 2:
The conduit is segmented into distinct functional zones: an insertion zone with enlarged cross-section for sheath protection, and a blocking zone with V-shaped profile for strand positioning. This segmentation allows each zone to perform its specific function without compromising the other.
2Ease of manufacture
If the sheath is stripped over the saddle length to accommodate V-profile conduits, then strands can be installed, but anti-corrosion protection is compromised and complex insulation measures are required
Solution Approach 1:
The conduit is pre-formed with an enlarged insertion zone that anticipates the need for sheath protection. This preliminary design feature allows the sheath to remain intact during installation, eliminating the need for subsequent stripping and complex insulation measures.
3Ease of operation
If the conduit cross-section is sufficient to allow easy threading of strands, then installation is facilitated, but the friction necessary to prevent sliding may be reduced
Solution Approach 1:
The conduit cross-section varies along its length: a larger insertion zone for easy threading, and a narrower blocking zone with V-profile for effective friction locking. This local quality differentiation resolves the contradiction between installation ease and friction effectiveness.
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 solution provides effective stress transmission and prevents sliding of strands, maintaining anti-corrosion protection while allowing the use of sheathed strands without stripping, thus enhancing structural integrity and reducing costs.
Implementation Method 1
Maintaining the strands in their duct, preventing them from sliding along the curved path, results from the friction of the strand in the support zone of the wall of the duct
Implementation Method 2
The strand is in contact with this support zone on a surface having a certain extent given the shape of an arc of a circle with a radius adapted to the strand. It is pressed against this support area by the tension applied to the cable.
Data Source
AI summary
The invention relates to a structural cable comprising multiple stretched strands (4). The cable is diverted in a device having a body through which passages (10) extend. Each passage has a wall for guiding one of the strands along a curved path. The wall of the passage includes a strand-supporting area (11) oriented towards the interior of the curvature of the path. The cross-section of the supporting area, transverse to the curved path and in the central part of the passage, takes the form of an arc of circle having a radius substantially equal to half of the outside diameter of the strand. The cross-section of the central part of the passage is larger outside of the supporting area.