Self-Installing Cable Bend Limiter for Marine Vessels
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Solution Overview
Problem
Cables connected to floating marine installations or vessels experience premature fatigue failure due to bending stresses from wave movements, and existing bend limiting devices require underwater work for installation and replacement, increasing costs and operational risks.
Innovation Solution
A bend limiting device with an elongated sleeve member and a pulling means that can be secured and detached by applying a pulling force on the cable, allowing for easy replacement without divers or underwater work, featuring a spiral wrap pulling means for efficient force application and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bend limiting device is installed to protect cables from fatigue failure, then cable reliability is improved, but the device requires underwater work for installation and replacement, increasing operational complexity and costs
Solution Approach 1:
The bend limiting device is designed to be self-installing through a self-service mechanism. When pulling force is applied to the cable, the sleeve member automatically engages with the transverse surface via friction and normal forces, securing itself without requiring underwater manual installation. The device also self-detaches when pulling force is removed, enabling easy cable replacement without diver intervention.
Solution Approach 2:
The sleeve member acts as an intermediary between the cable and the transverse surface. It transfers the pulling force from the cable to the transverse surface through friction and normal forces, creating a secure connection that protects the cable from bending fatigue while enabling automatic installation and detachment.
2Reliability
If traditional bend limiting devices are used, then cable protection is provided, but underwater work with divers is required, increasing operational risks and costs
Solution Approach 1:
The device eliminates the need for diver intervention by implementing self-service installation and detachment. The sleeve member automatically secures to the transverse surface when pulling force is applied and releases when pulling force is removed, completely removing the harmful factor of underwater manual work and associated operational risks.
3Reliability
If the sleeve member is secured tightly to prevent cable movement, then cable fatigue is reduced, but the device becomes difficult to detach for cable replacement
Solution Approach 1:
The connection between the sleeve member and transverse surface is dynamic rather than static. The friction force that secures the device during operation can be overcome by applying pulling force in the detachment direction, allowing the sleeve member to transition from a secured state to a detached state. This enables easy cable replacement while maintaining effective fatigue protection during normal operation.
Solution Approach 2:
The device is designed with preliminary anti-action for detachment. By applying pulling force in the detachment direction, the friction force is overcome in advance, allowing the sleeve member to detach smoothly. This preliminary action against the securing friction force enables easy cable replacement without damaging the device or cable.
4Strength
If mechanical fastening methods are used to secure the sleeve member, then attachment strength is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The complex mechanical fastening elements (screws, clips, latches) are extracted from the design. Instead, the invention uses a simple friction-based connection where the sleeve member's outer surface frictionally engages with the transverse surface. This extracted fastening mechanism reduces device complexity while maintaining adequate attachment strength through friction forces.
Solution Approach 2:
The attachment mechanism relies on changing the friction parameter. By applying pulling force, the normal force between the sleeve member and transverse surface increases, thereby increasing the friction force to secure the device. For detachment, pulling force in the opposite direction overcomes the friction, enabling simple attachment and detachment without complex fastening 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
The device effectively reduces cable fatigue and operational costs by enabling secure attachment and detachment without underwater work, enhancing operational reliability and reducing cable replacement expenses in wave power plants.
Implementation Method 1
the outer abutment surface of the sleeve member is configured to allow it to be secured against said rigid surface by applying a pulling force on the cable and the sleeve member secured thereto
Implementation Method 2
featuring a spiral wrap pulling means for efficient force application and detachment
Implementation Method 3
A bend limiting device with an elongated sleeve member and a pulling means that can be secured and detached by applying a pulling force on the cable
Data Source
Figure 1
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Figure 4
AI summary
A bend limiting device (100) for a cable (101') comprising at least one elongated sleeve member (104) with an entrance end (105) exhibiting an entrance opening (106) and an opposite exit end (107) exhibiting an exit opening (108) for the cable (101"), an outer abutment surface (109), disposed between the entrance end (105) and the exit end (107), for securing against a rigid surface (110) of a floating marine installation (103) or vessel, an axially th rough-going hole (111) between the entrance opening (106) and the exit opening (108) for accommodating a portion (101"') of the cable, and at least one clamping device (112) for securing said sleeve member (104) in a fixed position a round the cable portion (101"). The outer abutment surface (109) of the sleeve member (104) is configured to allow it to be secured against the rigid surface (110) by applying a pulling force (Fl) on the cable (101) in a direction from the abutment surface (109) to the rigid surface (110), as well as to be detached from the rigid surface (110) when the application of pulling force on the cable ceases,