Tap Plug Thread Sequencing for Reliable Lug and Stud Engagement

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Solution Overview

Problem

Existing tap plugs used in power distribution systems for high voltage cables are inadequate in terms of cost, ease of retrofitting, torque handling, suitability for 900 amp applications, hotstick installation, and ease of disassembly.

Innovation Solution

A tap plug design featuring a housing with a rotatable first member and second member, where the first member has an external thread to engage a conductor lug and the second member has an internal thread to engage a stud, along with a guide member and a torque application region to facilitate installation and disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If prior art tap plugs are used, then basic connection functionality is provided, but manufacturing cost, ease of retrofitting, torque handling, and disassembly ease are inadequate

Engineering Contradiction:

Improvemanufacturing costVSAvoidconnection reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The tap plug is divided into multiple independent members: a first member with external threads for conductor lug engagement, a second member with internal threads for stud engagement, and a housing. This segmentation allows each component to be manufactured separately using standard threading processes, reducing manufacturing cost while maintaining reliable threaded connections through precise thread engagement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first member is positioned within the housing, and the second member is positioned within the first member, creating a nested structure. This nesting arrangement compactly integrates multiple connection functions into a single plug assembly, reducing overall complexity and manufacturing cost while ensuring reliable electrical and mechanical connections through sequential thread engagement.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of operation

If prior art tap plugs are used, then connection functionality is provided, but ease of installation and disassembly is poor

Engineering Contradiction:

Improveease of installationVSAvoidplug structure complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The first and second members are pre-configured with external and internal threads respectively, allowing them to be preliminarily assembled with the housing and conductor lug before final installation. This preliminary threading configuration simplifies the installation process by enabling straightforward screw-on engagement without complex alignment procedures, while the modular structure keeps overall complexity manageable.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The rotatable members allow dynamic adjustment during installation and disassembly operations. The first member rotates to engage/disengage from the conductor lug, and the second member rotates to engage/disengage from the stud, providing operational flexibility that simplifies installation and removal while the constrained rotational mechanism keeps structural complexity controlled.

Inventive Principle:

Principle #15Dynamics

3Strength

If prior art tap plugs are used, then basic connection is achieved, but torque handling capability is insufficient

Engineering Contradiction:

Improvetorque handlingVSAvoidmechanical structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The first member combines both electrical conduction and mechanical torque transmission functions through its threaded engagement with the conductor lug. The second member similarly combines electrical connection and torque resistance through its threaded engagement with the stud. This merging of functions into single components enhances torque handling capability while avoiding the need for additional separate structural elements, thus controlling overall complexity.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If prior art tap plugs are used, then connection functionality is provided, but suitability for high amp applications is limited

Engineering Contradiction:

Improvehigh amp application suitabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The first member and second member are designed with specific local qualities: the first member has external threads optimized for high-current conductor lug engagement, while the second member has internal threads optimized for stud engagement. This localized optimization of thread specifications and material properties at critical connection points ensures high amp application suitability without requiring complex manufacturing processes for the entire assembly.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12283773B2Tap plugs configured to ensure thread-to-thread contact before housing-to-housing contact

Publication Date: 2025.04.22 HUBBELL INC

AI summary

A tap plug for engaging a conductor lug and a stud is provided. The tap plug includes a housing, a first member, and a second member. The housing has an inner bore defining a longitudinal axis. The first member is in the inner bore and is rotatable with respect to the housing about the longitudinal axis. The first member has an external thread at a first end, where the external thread engages the conductor lug. The second member is rotatable with respect to the housing about the longitudinal axis and has an internal thread at the first end. The first end is open so that the internal thread can engage the stud.