Terminal With Elastic Nut For Torque-Limited Conductor Clamping

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Solution Overview

Problem

The existing screw terminals for connecting electrical conductors to circuit breakers often require expensive torque wrenches and regular calibration, and may not provide the correct torque range, leading to unsafe and inefficient installation by unskilled workers.

Innovation Solution

A connection terminal with an intermediate stage featuring a nut with elastic branches that disengages in rotation when the correct tightening torque is reached, accompanied by a clicking noise, allowing for secure clamping without the need for specialized tools or calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If torque wrenches are used to tighten connection terminals, then the correct tightening torque can be achieved, but the cost increases and calibration is required

Engineering Contradiction:
Improvetightening torque precisionVSAvoidtool complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The terminal incorporates an integrated torque control mechanism with elastic branches that automatically regulate the tightening torque. The elastic branches deform under torque and disengage at a predetermined torque threshold, providing self-controlled tightening without external torque wrenches or calibration

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The elastic branches act as an intermediary mechanism between the screw and the terminal body. They transmit and limit the torque force, mediating the tightening process to achieve precise torque control while preventing over-tightening, thereby eliminating the need for complex external torque control devices

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If torque wrenches are used for tightening, then correct torque can be applied, but installation time increases due to calibration and tool handling

Engineering Contradiction:
Improvetightening torque precisionVSAvoidinstallation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The terminal's integrated elastic branch mechanism performs torque control automatically during the tightening process. Installers only need to rotate the screw without requiring torque wrench calibration or specialized tool handling, significantly reducing installation time while maintaining precise torque control

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The elastic branches are pre-configured during manufacturing with predetermined torque characteristics. This preliminary setup of the torque control mechanism eliminates the need for on-site calibration and preparation, allowing installers to proceed directly with tightening operations

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the terminal structure is simplified without torque control, then installation becomes easier, but tightening torque precision deteriorates

Engineering Contradiction:
Improveinstallation easeVSAvoidtightening torque precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The terminal maintains ease of operation by allowing simple screw rotation while incorporating self-service torque control through the elastic branches. The mechanism automatically regulates torque without requiring complex installation procedures, combining operational simplicity with precise torque control

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The torque control function is merged into the terminal structure itself through the integrated elastic branch mechanism. This combination of torque control and terminal structure eliminates the need for separate torque control devices, maintaining operational simplicity while ensuring precise torque application

Inventive Principle:
Principle #5Merging (Combining)

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

Enables secure and correct torque tightening of electrical conductors without specialized tools, ensuring safety and efficiency while allowing for precise sizing of terminal parts without additional mechanical oversizing.

Implementation Method 1

the two elastic branches are able to compress radially on screwing on slopes belonging to the cage, the torque resulting from the compression of the branches opposing the tightening torque of the screw

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

this terminal comprises means for producing a clicking noise as soon as the aforementioned exhaust from the branches of the slopes

Methodology Applied
Scientific EffectAcoustic emission: Acoustic Emission

Data Source

PatentEP3624270B1Terminal for connecting an electrical conductor to the connection pad of an electrical device, and electrical protection device including such a terminal
Publication Date: 2021.06.23 SCHNEIDER ELECTRIC IND SAS
  • EP3624270B1 patent drawingFigure 1~8
  • EP3624270B1 patent drawingFigure 9~14
  • EP3624270B1 patent drawingFigure 15~16

AI summary

The present invention relates to a connection terminal B for an electrical conductor to a connection pad belonging to an electrical device, such terminal B comprising a cage C adapted to be fixed inside the housing of the device and having an opening (8) of substantially parallelepiped shape delimited by four walls (4, 5, 6, 7), this opening (8) being adapted to receive the aforementioned pad, one (4) of the aforementioned walls of the cage, referred to as the upper wall, having an opening adapted to allow the passage of a screw (10), said screw having at one (10a) of its ends (10a, 10c) located outside the cage C, means for actuating said screw (10), and at its opposite end (10c), a clamping pad (11) adapted to allow the conductor to be clamped between the aforementioned pad and said pad (11) when the screw (10) is actuated, causing relative translational movement between the screw (10) and cage C.This terminal B is characterized in that it has an intermediate stage created inside the cage C so as to allow the housing of a nut (22) with elastic arms (25,26) having a threaded hole through which the clamping screw (10) is intended to be mounted screwed, said elastic arms (25,26) cooperating with forms provided on the lateral walls (6,7) of the cage C so that the nut (22) disengages in rotation when screwing as soon as the correct tightening torque is reached, and engages from the beginning to the end of unscrewing.