Electric appliance for personal care

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Solution Overview

Problem

Existing toothbrush designs face challenges in providing a universally usable, efficient, and secure attachment system that effectively transmits vibration from the handle to the brush attachment, while ensuring easy installation and a firm hold.

Innovation Solution

A toothbrush design featuring a plug-like coupling structure with a beveled abutment surface and an inclined axis of rotation, combined with a cam and recess mechanism, utilizing materials with different moduli of elasticity for a snap connection that enhances vibration transmission and longevity, and a geometric configuration that allows for precise handling and secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional vertical coupling structure is used, then the manufacturing is simpler, but the contact surface area is reduced and trigger weight is lower

Engineering Contradiction:
Improvecontact surface areaVSAvoidcoupling structure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by tilting the abutment surface at an angle α between 30° and 70° relative to the longitudinal axis of the handle. This asymmetric configuration increases the contact surface area between the plug-like and socket-like coupling structures compared to a conventional vertical arrangement, thereby improving guidance and trigger weight without requiring additional components

Inventive Principle:
Principle #4Asymmetry

2Length of moving object

If the abutment surface is positioned closer to the rear end, then the handle length is reduced, but the handling precision and control are worsened

Engineering Contradiction:
Improvehandle lengthVSAvoidhandling precision
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating an asymmetric distribution of the abutment surface along the handle length. The dimension from the abutment surface to the rear end is made greater at the front than at the rear, forming a running surface that provides enhanced control and precision in the thumb grip area while maintaining overall compact dimensions

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the vibration drive is positioned far from the coupling interface, then the motor placement is easier, but the vibration transmission effectiveness is reduced

Engineering Contradiction:
Improvemotor placement easeVSAvoidvibration transmission effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies dimensionality change by tilting the axis of rotation of the electric motor at an angle φ between 35° and 90° relative to the longitudinal axis of the handle. This angular arrangement allows the vibration drive to be positioned optimally for manufacturing while maintaining effective vibration transmission through the coupling interface by utilizing a different spatial dimension

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

4Duration of action of stationary object

If softer material is used for the attachment part, then the snap connection longevity is improved, but the structural strength is reduced

Engineering Contradiction:
Improvesnap connection longevityVSAvoidstructural strength
Core Design Contradiction:
Duration of action of stationary objectVSStrength

Solution Approach 1:

The patent applies parameter changes by selecting materials with different moduli of elasticity for the handle and attachment part. The attachment part uses softer material (lower elastic modulus) that deforms elastically during snap connection formation, improving longevity by absorbing stress and reducing wear on the cam mechanism, while the overall structural strength is maintained through the harder handle material and geometric design

Inventive Principle:
Principle #35Parameter changes

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 design achieves improved vibration transmission, secure attachment, and extended longevity of the snap connection, ensuring effective and efficient use across various applications, including electric and manual toothbrushes.

Implementation Method 1

The material from which the hand body or the main body of the hand body (and in particular also the cam) is made is harder than the material from which the attachment part or the main body of the attachment part (and in particular also the recess) is made

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3928659B1Electric appliance for personal care
Publication Date: 2023.07.26 TRISA HLDG AG
  • EP3928659B1 patent drawingFigure 1a~1b
  • EP3928659B1 patent drawingFigure 1c~1d
  • EP3928659B1 patent drawingFigure 1e~1f

AI summary

The present invention relates to a toothbrush with a handle (1) having a longitudinal axis AG and an attachment (60) that can be placed on the handle (1), wherein the handle (1) has a hand body (1d) with a base body and the attachment (60) has a base body, wherein a plug-like coupling structure (40) projects from the handle (1) and forms an interface X with a substantially opposite socket-like coupling structure (70) of the attachment (60), wherein a stop surface (44) of the handle (1) for the attachment (60) extends obliquely to the longitudinal axis AG of the handle (1), wherein a longitudinal axis AA of the attachment designates the longitudinal axis of the socket-like coupling structure (70), which lies in the base region of the attachment (60), wherein a longitudinal axis AB of the head region lies accordingly in the head region of the attachment (60), and wherein an angle Δ between AA and AB 10° and 30°.