Personal Care Appliance Plug Geometry for IP-Class Connector Matching

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Solution Overview

Problem

Personal care appliances designed for use in wet conditions face challenges with electrical connectors and power supply devices due to remnant moisture, leading to issues like electrolysis and improper IP class compatibility.

Innovation Solution

A kit featuring personal care appliances and power supply devices with socket and plug geometries specifically designed to ensure compatibility based on IP classes, preventing insertion of plugs with lower IP classes and allowing only compatible plugs to connect, thereby reducing electrical creepage and ensuring watertightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If personal care appliances are designed for use in wet conditions with high IP class, then water resistance is improved, but electrical connector compatibility becomes problematic due to remnant moisture causing electrolysis

Engineering Contradiction:

Improvewater resistanceVSAvoidelectrolysis of electrical contacts

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the connector design into multiple geometric variants (different socket and plug geometries) corresponding to different IP classes. This segmentation allows the system to match connectors based on water resistance requirements, preventing electrolysis by ensuring compatible IP class pairing between power supply devices and personal care appliances.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning specific geometric characteristics to different parts of the connector system. Each socket geometry is designed to accept only plug geometries with equal or higher IP class ratings, creating localized compatibility rules that prevent harmful electrochemical reactions while maintaining overall system reliability.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If multiple socket geometries are provided for different IP classes, then IP class compatibility is improved, but device complexity increases

Engineering Contradiction:

ImproveIP class compatibilityVSAvoidnumber of socket geometries

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a unified connector system where a single socket geometry can accept multiple plug geometries (its own geometry and those with higher IP classes). This multi-functionality approach allows one socket design to serve multiple IP class compatibility purposes, reducing the need for entirely separate connector systems for each IP class.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs asymmetry in the geometric design of sockets and plugs, where socket geometries are designed with specific asymmetric features that allow insertion of certain plug geometries while preventing insertion of others. This asymmetric design enables compact differentiation of multiple geometries within a unified system, managing complexity through clever geometric relationships rather than numerous separate designs.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentEP4300757A1Kit of personal care appliance and power plug

Publication Date: 2024.01.03 BRAUN GMBH

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AI summary

A kit comprises a personal care appliance (11, 12) and a power supply device (40). The personal care appliance (11, 12) and power supply device (40) may have mating connectors.