Screw Terminal Torque Indication via Elastic Wing Contact

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Solution Overview

Problem

Existing screw terminals lack a practical indication of the tightening torque, leading to potential loosening and frequent manual checks, despite creep compensation, which increases operation time and uncertainty.

Innovation Solution

A connection system with a pressure device and detection means that includes a conductive pressure device with symmetrical concave wings, a first element on the housing wall, and a second element on the wing, which come into contact to actuate signaling means, such as a light-emitting diode, when a predetermined tightening torque is reached, ensuring reliable and quick connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If creep compensation means are added to prevent loosening, then reliability is improved, but device complexity increases and no tightening indication is provided

Engineering Contradiction:
Improvetightening qualityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the creep compensation function and the tightening indication function into a single integrated pressure device. The pressure device with elastic wings provides both creep compensation through its elastic deformation and tightening indication through the contact between detection elements, eliminating the need for separate mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure device serves itself by using its own deformation during compression to trigger the indication mechanism. The detection elements are positioned such that their contact is a natural consequence of the pressure device's compression, allowing the device to indicate its own tightening status without external monitoring systems.

Inventive Principle:
Principle #25Self-service

2Device complexity

If no tightening indication is provided, then device complexity is reduced, but loss of information occurs and operation time increases due to trial and error

Engineering Contradiction:
Improvestructure simplicityVSAvoidtightening status information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where the tightening status is immediately visible through the indication means (such as a light-emitting diode). The detection elements convert the mechanical state of the pressure device into a visible signal, providing real-time feedback to the operator about whether the tightening torque has reached the threshold.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The indication means utilizes visual changes (such as light emission from an LED) to communicate the tightening status. This provides clear, immediate visual feedback without requiring complex mechanical indicators or additional information processing.

Inventive Principle:
Principle #32Color changes

3Reliability

If regular tightening checks are performed to ensure quality, then reliability is maintained, but productivity decreases due to increased operation time

Engineering Contradiction:
Improveconnection qualityVSAvoidinstallation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent performs the tightening quality assurance action preliminarily and continuously through the indication mechanism. Rather than requiring periodic checks after installation, the system provides continuous visual feedback during the tightening process itself, allowing the operator to know immediately when the correct torque is achieved.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual tightening checks with an automated indication system. The detection elements and signaling mechanism automatically monitor and indicate tightening status, eliminating the need for operator intervention or repeated manual verification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system provides a clear visual indication of sufficient tightening, reducing operation time and eliminating unnecessary checks, while ensuring reliable connection and preventing loosening due to creep.

Implementation Method 1

actuate signaling means, such as a light-emitting diode

Methodology Applied
Scientific EffectLight-emitting diode: Light Emitting Diode

Implementation Method 2

an elastic pressure piece which is applied to the electrical conductor. The pressure piece comprises a head area and a pressure area interconnected by an elastic wing capable of storing tightening energy

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2383841B1Connecting system enabling the tightening torque of a screw terminal to be indicated
Publication Date: 2013.01.30 SCHNEIDER ELECTRIC IND SAS
  • EP2383841B1 patent drawingFigure 1A~2

AI summary

The system (50) has detection units for detecting a predetermined tightening torque of a screw and comprising a stop element integrated to a wall (60) and another stop element (40) integrated to a wing. The wing and the wall are adjacent to one another when a screw terminal (10) is fixed in a housing. A determination unit determines a distance separating the stop elements. An indicating unit (42) e.g. LED, is coupled with the determination unit, and indicates when the distance is smaller than or equal to a threshold distance. An independent claim is also included for an electrical equipment comprising a fixed connection strip in a connection tunnel.