Bending Restrictor for Intervention Cable with Articulated Spherical Joints
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Solution Overview
Problem
Existing bending restrictors for rigid, resilient intervention cables suffer from undefined smallest allowable bending radius, deformation under point contact forces, and complex assembly processes due to multiple components and short link lengths, leading to uneven tension and safety issues during cable handling.
Innovation Solution
A bending restrictor comprising a chain of pipe sections linked by splittable articulation sleeves with guide sheaves, allowing the intervention cable to pass through and pivoting within a limited angle, with each articulation sleeve splitable into two halves for simplified assembly and featuring spherical sector seats and flattened pivot funnels to manage bending moments effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bending restrictor with multiple components and short links is used, then the cable can be restricted from excessive bending, but the assembly process becomes complex and time-consuming
Solution Approach 1:
The patent combines multiple separate components (pipe sections, articulation sleeves, guide sheaves) into an integrated articulation sleeve assembly where the guide sheave is mounted directly on the articulation sleeve. This merging reduces the number of discrete parts and simplifies the assembly process while maintaining the bending restriction function through the articulated mechanism.
2Reliability
If pipe sections with spherical sectors and ring collars are used to limit bending, then the cable bending radius is controlled, but large point contact forces cause deformation at the contact points
Solution Approach 1:
The patent employs spherical sectors at the ends of pipe sections that articulate within spherical sector seats in the articulation sleeves. This spherical geometry distributes contact forces over a curved surface area rather than concentrated point contacts, reducing local stress and deformation while maintaining effective bending radius control through the spherical articulation mechanism.
3Ease of operation
If an air span is used between the gooseneck and drum, then the cable can move freely, but uneven tension and back tension occur leading to safety issues
Solution Approach 1:
The patent creates a dynamic articulated structure where multiple pipe sections connected by articulation sleeves can pivot and adapt to cable movement while maintaining geometric constraints. This dynamic configuration allows the cable to move freely through the articulated path while the structure itself adjusts to maintain uniform tension distribution, eliminating the uneven back tension problems of fixed air span configurations.
Data Source
AI summary
A bending restrictor for a rigid but resilient rod-shaped intervention cable includes a series of pipe sections and articulation sleeves. Each pipe section includes a straight pipe piece with a spherical sector in either end. Each articulation sleeve includes two axially oppositely directed spherical-sector seats for holding about each pipe's spherical sector. The spherical sector seats are arranged in either ends of a central axial passage for the intervention cable. Two guide sheaves each with its sheave groove reside in the articulation sleeve's axial plan is laterally displaced relative to the middle of the axial passage so as for enveloping the axial passage for the intervention cable. The articulation sleeve is provided with two opposite axially directed and flattened pivot funnels, and each pivot funnel is provided with its narrower end in adjacent to each its spherical-sector seat. Each pivot funnel has, in the axial plane a funnel shape which allows the pipe section's straight pipe piece to pivot about the spherical sector seat in the axial plane, and wherein the pivot funnel's funnel shape is flattened in another axial plane perpendicular to the first axial plane, so as for the pipe sections to be able to pivot only in the first axial plane. The articulation sleeve is splittable in the plane into two articulation sleeve half housings.