Dual Messenger Rolling Spacer for Safer Overhead Cable Pulling
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Solution Overview
Problem
The installation of overhead transmission and distribution cables is costly and hazardous due to the need for frequent replacement of devices and the use of bosun chairs in inaccessible spans, which poses risks to utility workers.
Innovation Solution
A dual messenger rolling cable spacer system that allows preassembled cables and spacers to be pulled across spans using a secondary messenger wire, eliminating the need for permanent retention components and reducing worker exposure to danger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cable spacers with permanent retention components are used, then cables are securely retained in aerial positions, but installation costs and time increase due to frequent replacement of devices
Solution Approach 1:
The cable spacer is designed with a roller element that enables it to move dynamically along the messenger wire. The roller allows the spacer to be pulled into position during installation and then rolls freely to accommodate thermal expansion and contraction of the cable, eliminating the need for frequent device replacement while maintaining secure retention.
Solution Approach 2:
The cable and spacer are pre-assembled on the ground before being installed on the messenger wire. This preliminary assembly eliminates the need for workers to attach components individually at height, significantly reducing installation time and improving productivity while ensuring proper configuration before deployment.
2Adaptability or versatility
If bosun chairs are used to install cables in inaccessible spans, then cable installation is enabled across difficult terrain, but worker safety is compromised
Solution Approach 1:
The invention extracts the worker from the hazardous installation environment by using a pre-assembled cable-spacer unit that can be pulled into position using a secondary messenger wire. This eliminates the need for workers to use bosun chairs or trolleys in inaccessible spans, removing them from harm's way while still enabling installation across difficult terrain.
Solution Approach 2:
A secondary messenger wire is introduced as an intermediary tool to pull the pre-assembled cable-spacer unit across inaccessible spans. This mediator enables the transfer of the cable assembly to difficult-to-reach areas without requiring direct human intervention at height, thereby maintaining adaptability while improving worker safety.
3Reliability
If multiple installation devices are replaced with permanent fixtures, then cable support is established, but the cost and time for installation increase significantly
Solution Approach 1:
The cable and spacer are pre-assembled on the ground before installation. This preliminary action allows all connection and configuration work to be performed at ground level, eliminating time-consuming operations at height and significantly reducing overall installation time while maintaining support stability.
Solution Approach 2:
The roller mechanism provides dynamic adjustment capability that eliminates the need for multiple fixed installation devices. The single rolling spacer can accommodate cable movement and tension changes, providing stable support with fewer components, which reduces both installation time and the number of devices that need to be replaced.
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
This system reduces installation costs and minimizes the risk to utility workers by enabling cable installation without permanent retention devices and eliminating the need for bosun chairs in inaccessible areas.
Implementation Method 1
Each of the one or more rolling spacers may be hung from the carrier messenger wire via a roller of the one or more rolling spacers such that the roller is in contact with the carrier messenger wire. The one or more rolling spacers may be configured to roll along the carrier messenger wire when hung from the carrier messenger wire.
Data Source
AI summary
An apparatus for installing cables in overhead transmission and distribution systems and a corresponding method of use are disclosed herein. The apparatus described herein may comprise a dual messenger rolling cable spacer used to install cables in overhead transmission and distribution systems. In various embodiments, the method of using the dual messenger rolling cable spacer may include installing a carrier messenger wire across a span between utility structures. One or more rolling spacers may then be hung from the carrier messenger wire via a roller such that the roller is in contact with the carrier messenger wire. A set of cables and a circuit messenger wire may be affixed to the one or more rolling spacers. The circuit messenger wire may then be pulled across the span causing the one or more rolling spacers to roll along the carrier messenger wire, thereby pulling the set of cables across the span.