Insulation Plug Sleeve for Easier Thread Engagement

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Solution Overview

Problem

Traditional insulation plugs for medium-voltage and high-voltage separable connectors require strong manual force for insertion, leading to misalignment and damage of threads, making them difficult to engage and potentially unusable.

Innovation Solution

An insulation plug design featuring a tubular sleeve with an inner sleeve thread that protrudes from the plug thread, allowing initial engagement with the connection stud at a lower insertion depth, reducing the required mechanical force and risk of thread damage, and incorporating a sensing capacitor for voltage sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the insulation plug is pushed deep into the rear cavity to engage the plug thread with the connection stud, then the insulation plug can be securely installed, but strong manual force is required which can damage the threads due to misalignment

Engineering Contradiction:
Improvesecure installation of insulation plugVSAvoidease of inserting insulation plug
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A tubular alignment sleeve is introduced as an intermediary component between the insulation plug and the connection stud. The sleeve features an outer alignment thread that engages with a groove in the connection stud, guiding and aligning the plug during insertion. This mediator enables thread engagement without requiring strong manual force, preventing thread damage while ensuring reliable installation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the plug thread directly engages with the connection stud thread, then the insulation plug can be secured, but misalignment during forcing can damage either thread making engagement impossible

Engineering Contradiction:
Improvethread engagementVSAvoidthread alignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The alignment sleeve performs preliminary alignment action before the plug thread engages with the connection stud thread. The outer alignment thread of the sleeve engages with the groove in the connection stud first, pre-positioning and aligning the components. This preliminary alignment ensures that when the plug is subsequently inserted, the threads are already properly aligned, preventing damage and ensuring successful engagement.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the insulation plug is designed with a simple plug body, then manufacturing is easier, but thread engagement requires strong force and risks damage

Engineering Contradiction:
Improvesimplicity of plug bodyVSAvoidthread engagement reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The insulation plug system is segmented into distinct functional components: the plug body, the alignment sleeve, and the connection stud. The alignment sleeve is a separate component that can be manufactured independently with precise threading, then assembled onto the plug body. This segmentation allows each component to be optimized for its specific function - the sleeve for alignment and engagement, the plug body for insulation - improving overall reliability without significantly complicating manufacturing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4304029A1Insulation plug and insatlling process thereof
Publication Date: 2024.01.10 3M INNOVATIVE PROPERTIES CO
  • EP4304029A1 patent drawingFigure 1
  • EP4304029A1 patent drawingFigure 2
  • EP4304029A1 patent drawingFigure 3

AI summary

Insulation plug (1) for being inserted into a rear cavity (70) of a medium-voltage or high-voltage separable connector (10) for connecting a power cable to a bushing (40) in a power distribution network. In use, the insulation plug insulates a threaded connection stud (90) for attaching the separable connector (10) to the bushing (40). The insulation plug (1) comprises a) a plug body (140) b) a thread block (170), affixed in the plug body (140), and comprising an internal plug thread (180) for securing the insulation plug (1) in the rear cavity (70); c) a tubular sleeve (200) comprising i) a radially outer surface comprising an outer sleeve thread (210); ii) a radially inner surface comprising an inner sleeve thread (220). The inner sleeve thread (220) is adapted to threadedly engage with the connection stud (90). The outer sleeve thread (210) is threadedly engaged with the plug thread (180), and a portion (230) of the inner sleeve thread (220) protrudes axially from the plug thread (180), such that upon insertion the protruding portion (230) can threadedly engage the connection stud (90).