Moisture-Resistant Power Plug Geometry for Personal Care Appliances

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Solution Overview

Problem

Personal care appliances face challenges with electrical connectors and power supply devices due to remnant moisture, leading to issues like electrolysis and inadequate ingress protection, which can reduce appliance life and safety.

Innovation Solution

The design of male and female connectors with specific geometries ensures proper fitting and watertightness by allowing insertion of plugs with matching or higher IP classes while preventing insertion of those with lower IP classes, and includes features like curved circumferential wall segments, projections, and notches to enhance electrical creep resistance and prevent reverse polarity insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrical connectors are used in personal care appliances, then the appliance can be powered, but remnant moisture causes electrolysis of electrical contacts reducing appliance life

Engineering Contradiction:

Improveappliance lifeVSAvoidelectrolysis from remnant moisture

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a third dimension to connector design by specifying the radius of curvature of circumferential wall segments. This geometric parameter creates a three-dimensional barrier structure that prevents moisture accumulation in the connector cavity, thereby eliminating electrolysis pathways while maintaining electrical connectivity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent converts the harmful effect of remnant moisture by designing curved circumferential wall segments that actively prevent moisture accumulation. The curvature geometry transforms potential moisture traps into drainage-friendly surfaces, turning a harmful environmental factor into a design consideration that enhances reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If power supply devices with inadequate ingress protection are used, then compatibility is improved, but safety and moisture protection are reduced

Engineering Contradiction:

ImprovecompatibilityVSAvoidingress protection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent creates a universal connector design where the curved circumferential wall structure serves multiple functions: it provides ingress protection for wet conditions, maintains mechanical connectivity, and ensures proper mating between plug and socket. This multi-functional geometry enables both compatibility and protection simultaneously.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If connector geometries without specific curvature constraints are used, then manufacturing is simpler, but electrical creep resistance is reduced

Engineering Contradiction:

Improveconnector manufacturingVSAvoidelectrical creep resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent specifies a quantitative parameter constraint (radius of curvature) for the circumferential wall segments. This parameter change transforms the connector geometry into a moisture-resistant configuration while remaining compatible with standard manufacturing processes, thus maintaining ease of production while enhancing reliability.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4300756A1Personal care appliance, power plug, and kit

Publication Date: 2024.01.03 BRAUN GMBH

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AI summary

Personal care appliances (11, 12), power supply devices (40), and kits comprising the same are disclosed. The personal care appliance (11, 12) and power supply device (40) may have mating connectors.