Rotating Pull-In Head Assembly for Twist-Free Cable Installation
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Solution Overview
Problem
The installation of subsea power cables is prone to damage due to sudden tension spikes and twisting, which can lead to costly delays and equipment damage, especially when using Cable Protection Systems, as existing winching systems struggle with torque transfer and rotational constraints.
Innovation Solution
A pull-in head assembly with a retaining member having a conical outer profile and a bearing surface with low friction, allowing the elongate flexible structure to rotate and reducing torque transfer, while a connector with an annular groove secures the assembly to the Cable Protection System, minimizing twisting and tangling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a winching cable is used to pull the cable and Cable Protection System into a structural interface, then the cable and protection system can be installed, but the winching cable becomes prone to entanglement and twisting due to rotational freedom and torque wind-up
Solution Approach 1:
The pull-in head incorporates a rotational degree of freedom that allows the cable to rotate freely as it is pulled into the structural interface. This dynamic rotation prevents torque wind-up and eliminates entanglement of the winching cable by allowing the system to self-adjust its rotational state during installation.
Solution Approach 2:
The pull-in head acts as an intermediary device between the winching cable and the cable assembly. It provides a controlled interface that manages the interaction forces, allowing the winching cable to pull the assembly without direct rotational coupling that would cause entanglement.
2Reliability
If the Cable Protection System is constrained using latches or latching features, then the protection system can be securely installed, but the installation becomes problematic due to increased complexity and potential snagging
Solution Approach 1:
The patent removes the latching mechanism from the Cable Protection System entirely. Instead of using complex latches or latching features to constrain the protection system, the design relies on the pull-in head and winching cable arrangement to achieve secure installation, thereby eliminating the source of installation problems.
Solution Approach 2:
Rather than constraining the Cable Protection System with latches during installation and then removing constraints, the invention inverts the approach by using a pull-in head that is naturally engaged during pulling and then naturally released after installation, eliminating the need for active constraint mechanisms.
3Adaptability or versatility
If two winching cables are used to install the cable and Cable Protection System separately, then each component can be installed independently, but the system requires synchronization and increases the risk of entanglement
Solution Approach 1:
The patent merges the function of two separate winching cables into a single integrated pull-in head system. The pull-in head is designed to be attached to both the cable and the Cable Protection System simultaneously, allowing both components to be installed together through a single winching operation, thereby eliminating synchronization requirements and reducing overall system complexity.
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 effectively reduces the risk of twisting and tangling during cable installation, ensures predictable force application, and allows for reliable release of the pull-in head assembly, thereby minimizing damage and operational delays.
Implementation Method 1
a bearing surface with low friction, allowing the elongate flexible structure to rotate and reducing torque transfer
Data Source
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AI summary
A pull-in head assembly (8) for releasably connecting a pulling arrangement (112) to an elongate flexible structure (4, 6). The pull-in head assembly (8) comprises a body (30) which defines a pulling axis X of the pull-in head and a retaining member (32) which is configured to secure the pull-in head assembly (8) to an elongate flexible structure (4, 6) such that a pulling force exerted on the body (30) along the pulling axis X is transferred to the elongate flexible structure (4, 6). The pull-in head assembly (8) is configured such that, in use, the body (30) and the elongate flexible structure (4, 6) are rotatable with respect to each other about the pulling axis X.