Mains Plug Ejection Lever with Elastic Support Arms

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Solution Overview

Problem

Existing electrical mains plugs are prone to jamming or pulling out of sockets when cables are stretched or tensile forces are applied, posing a risk of electric shock and failure to comply with safety norms due to inadequate ejection mechanisms.

Innovation Solution

An electrical mains plug design featuring a carrier body with elastically deformable support arms and a pivoting ejection lever with a large pivoting angle, allowing for a significant ejection stroke without jamming, and incorporating a grounding plate for enhanced safety and compliance with VDE standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid plug body is firmly connected to the electrical cable, then structural stability is improved, but the risk of the plug becoming jammed in the socket when pulling force is applied increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidrisk of jamming
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The plug body is divided into two separable halves (first and second plug halves) that can move relative to each other. This segmentation allows the plug to maintain structural stability during normal use while enabling one half to be ejected from the socket when pulling force is applied, preventing jamming.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The plug incorporates a dynamic ejection mechanism where the first plug half can be selectively ejected from the socket while the second plug half remains in place. This dynamic capability allows the plug to adapt to pulling forces by enabling controlled separation, transforming a static rigid structure into a dynamically responsive system.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the ejection lever arm is designed with a grounding contact, then electrical safety is improved, but the electrical connection to earth is interrupted before plug pins are disconnected which violates safety standards

Engineering Contradiction:
Improveelectrical safetyVSAvoidcompliance with safety standards
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

Instead of having the grounding contact on the ejection lever arm as in prior art, the invention inverts the approach by providing the grounding contact on the second plug half that remains in the socket. This ensures the earth connection is maintained through the stationary plug half while the movable first plug half is ejected, reversing the conventional arrangement to comply with safety standards.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The grounding contact function is extracted from the ejection lever arm and transferred to the second plug half. This separation of functions allows the ejection mechanism to operate independently while the grounding function is maintained through the stationary plug half, eliminating the conflict between ejection operation and earth connection maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If the ejection lever is mounted on offset axle stubs with parallel ejection elements, then the ejection mechanism is simplified, but the ejection stroke is insufficient to reliably remove the plug from the socket

Engineering Contradiction:
Improveejection mechanism complexityVSAvoidejection stroke
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The invention transitions from a planar ejection mechanism to a three-dimensional separation mechanism. The first plug half is separated into the socket insertion direction (longitudinal dimension) while the second plug half remains stationary, creating ejection motion in multiple dimensions rather than relying solely on lateral lever arm movement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The ejection mechanism uses dynamic separation where the first plug half can move independently in the insertion direction relative to the second plug half. This dynamic separation provides sufficient ejection stroke without requiring complex lever arm mechanisms, as the movable plug half can be ejected along the socket insertion path.

Inventive Principle:
Principle #15Dynamics

4Ease of manufacture

If the plug body is constructed from two separate halves connected by a connecting screw, then assembly flexibility is improved, but certification difficulty and assembly impracticality increase

Engineering Contradiction:
Improveassembly flexibilityVSAvoidcertification and assembly difficulty
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The first and second plug halves are merged into a single integrally formed plug body. This eliminates the need for connecting screws and separate assembly steps, simplifying both manufacturing and certification processes while maintaining the functional benefits of separable plug halves for the ejection mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrally formed plug body serves multiple functions: it provides structural stability, enables the ejection mechanism through internal cavity design, and simplifies certification by eliminating separate connection components. The single-piece construction universally addresses manufacturing, assembly, and certification requirements.

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

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

Ensures safe and reliable ejection of the plug from the socket without tilting, maintaining structural stability, and meeting safety standards by providing a secure earth connection and sufficient pull-off force.

Implementation Method 1

a pair of axle stubs, each with a free end pointing towards one another, formed on one of two parallel, elastically deformable support arms

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3089281B1Electrical mains plug
Publication Date: 2019.06.19 SCHAUM GMBH
  • EP3089281B1 patent drawingFigure 1~2
  • EP3089281B1 patent drawingFigure 3
  • EP3089281B1 patent drawingFigure 4

AI summary

Disclosed is an electrical mains plug (1) with a carrier body (3) having bearing elements (11), a base plate (21) arranged on a front side and firmly connected to the carrier body, a housing cover (4) placed on the base plate (21) and receiving the carrier body (3), two plug contact pins (5) fixed to the carrier body (3) which are guided through the base plate (21) and project from the base plate (21) at the front, an ejection lever (9) having a bearing structure (12) and pivotably fixed to the bearing elements (11) of the carrier body (3) between a contact position and an ejection position, the lever having a cable guide section (13) connectable to an electrical cable (2) on a first side of the lever arm extending from the bearing structure (12) and two parallel sections extending from the bearing structure (12) on a second side of the lever arm.The ejection lever arms (15) are positioned at a distance from one another, the cable guide section (13) extending through the housing cover (21) on a rear side opposite the front side, the ejection lever arms (15) being located within the housing cover (4) in the contact position of the ejection lever (9), and the ejection lever arms (15) extending through passage slots (22) formed in the base plate (21) on the front side in the ejection position of the ejection lever (9), the bearing elements (11) formed on the support body (3) being a pair of axle stubs, each with a free end facing one another, formed on one of two parallel, elastically deformable support arms (10) formed on the support body (3) leaving a gap between them, and the bearing structure (12) on the ejection lever (9) having a circular cross-section.These are recesses corresponding to and receiving the axle stubs.