Rail-Mounted Electrical Equipment Grounding via Elastic Clip

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Solution Overview

Problem

Existing electrical equipment fails to provide reliable and cost-effective grounding of printed circuit boards against electromagnetic disturbances, with risks of user forgetfulness and connection breakage due to vibrations, especially in contactors.

Innovation Solution

The electrical equipment features a semi-rigid conductive clip made of bronze wire that establishes a permanent, elastic mechanical and electrical connection between the printed circuit board's ground terminal and a rail, ensuring grounding without operator intervention and minimizing the risk of connection failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cable connection from external earth terminal is used, then grounding can be achieved, but the connection may be damaged during use and requires operator intervention

Engineering Contradiction:
Improvegrounding connection reliabilityVSAvoidoperator intervention requirement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The grounding system automatically establishes electrical contact between the printed circuit board and the rail through elastic mechanical support during mounting, without requiring any operator intervention. The elastic blocking member and connection element work autonomously to maintain grounding throughout the equipment's operational life.

Inventive Principle:
Principle #25Self-service

2Reliability

If soldering a conductive tab on printed circuit board is used, then grounding connection can be established, but the weld may break due to vibrations

Engineering Contradiction:
Improvegrounding connection stabilityVSAvoidwelded connection strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The elastic blocking member incorporates a curved or flexible geometry that allows it to deform elastically under vibration, maintaining continuous electrical contact between the connection element and the rail, thereby preventing connection failure due to mechanical stress.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The system transitions from a rigid welded connection to an elastic mechanical connection, changing the physical state and mechanical properties of the grounding path to accommodate vibrations while maintaining electrical continuity.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If a complete metal mounting plate is used, then heat dissipation function is improved, but metal consumption increases significantly

Engineering Contradiction:
Improveheat dissipation capabilityVSAvoidmetal consumption
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The invention extracts only the essential grounding function from the complete metal mounting plate, using a localized elastic blocking member and connection element instead of a full metal plate, thereby reducing material consumption while maintaining grounding effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The elastic blocking member serves multiple functions: it provides mechanical support for mounting the equipment on the rail, establishes electrical contact for grounding, and accommodates thermal expansion and vibration, replacing the need for a complete metal plate.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If a rotating cam with strip is used for grounding, then selective grounding can be achieved, but user forgetfulness may occur and equipment operation may become dangerous

Engineering Contradiction:
Improveselective grounding capabilityVSAvoidgrounding assurance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The grounding connection is established automatically during the mounting process itself, before the equipment begins operation. The elastic blocking member and connection element are positioned and engaged as part of the installation procedure, ensuring grounding is in place before any electrical operations commence.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system automatically maintains grounding through the elastic mechanical support and direct electrical contact with the rail throughout operation, eliminating the need for manual intervention or monitoring by the operator.

Inventive Principle:
Principle #25Self-service

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 solution provides reliable and economical grounding of electronic components, ensuring consistent protection against electromagnetic disturbances and maintaining electrical contact stability over time, even under vibrations.

Implementation Method 1

an elastic blocking member (44) of the housing (22) on the rail (4)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least one ground terminal (48) of the printed circuit board (40) is electrically connected to the rail (4)

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3544120B1Electrical equipment and method for earthing such equipment
Publication Date: 2021.02.24 SCHNEIDER ELECTRIC IND SAS
  • EP3544120B1 patent drawingFigure 1~2
  • EP3544120B1 patent drawingFigure 3~4
  • EP3544120B1 patent drawingFigure 5~6

AI summary

This electrical equipment (2) comprises a housing (22) for mounting on a rail (4), and a control module (34) including a printed circuit board (40). In the rail-mounted configuration of the electrical equipment (2), at least one ground terminal (48) of the printed circuit board (40) is permanently electrically connected to the rail (4) by elastic mechanical support and direct electrical contact with a connecting element (50), itself in elastic mechanical support and direct electrical contact with the rail or with an elastic locking device (44) for the housing on the rail. The connecting element is a semi-rigid conductive clip (50) made of a shaped metal wire to electrically connect the ground terminal (48) and the rail (4).