Indexed Toothbrush Drive With Selectable Brushing Modes

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Solution Overview

Problem

Conventional electric toothbrushes provide a single non-variable brushing motion, which is not effective or efficient for cleaning all parts of the teeth, gums, and tongue, as the direction of the brushing motion remains the same regardless of the area being cleaned.

Innovation Solution

A drive system comprising concentric inner and outer rotatable shafts with an indexing assembly and converter mechanisms that allow for selective transmission of drive from the motor to the toothbrush head, enabling multiple brushing modes by translating linear displacement of a carriage into limited angular displacement, and synchronizing the rotation of both shafts to adjust the brushing direction based on the part of the mouth being cleaned.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single non-variable brushing motion is used, then the device complexity is reduced, but the adaptability to different mouth areas deteriorates

Engineering Contradiction:
Improvedrive system complexityVSAvoidbrushing motion adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic drive system where the carriage can be selectively positioned at different locations along the inner shaft, allowing the brushing motion characteristics to change dynamically based on the selected position. This enables multiple brushing modes (different directions and patterns) while maintaining a relatively simple overall structure, resolving the contradiction between device complexity and adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The carriage acts as an intermediary component between the motor and the outer shaft. By selectively positioning the carriage at different locations, the system can transmit motor drive to different parts of the outer shaft, thereby changing the brushing motion direction and pattern without requiring multiple complex drive mechanisms, thus achieving high adaptability with controlled complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple brushing modes are implemented, then the adaptability to different mouth areas is improved, but the device complexity increases

Engineering Contradiction:
Improvebrushing mode varietyVSAvoidindexing assembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The indexing assembly is segmented into discrete positioning locations along the inner shaft, with each location corresponding to a specific brushing mode. This segmentation allows the system to achieve multiple brushing modes through a simple selective positioning mechanism rather than a continuous complex control system, reducing the overall device complexity while maintaining versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The carriage and indexing assembly are designed as universal components that can serve multiple functions. The same indexing mechanism enables selection between different brushing modes, and the carriage itself participates in both the indexing operation and the drive transmission, reducing the need for separate dedicated components for each function and thereby reducing device complexity.

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

3Adaptability or versatility

If the carriage is reciprocally displaceable along the inner shaft, then the adaptability of brushing direction is improved, but the ease of operation deteriorates

Engineering Contradiction:
Improvebrushing direction controlVSAvoidmode switching operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The indexing assembly employs periodic indexing positions along the inner shaft, where the carriage can be quickly and easily positioned at predetermined locations corresponding to different brushing modes. This periodic arrangement allows for simple, discrete mode switching rather than continuous adjustment, improving ease of operation while maintaining adaptability through the availability of multiple distinct brushing directions.

Inventive Principle:
Principle #19Periodic action

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 drive system allows for precise control of brushing motions, enabling effective cleaning of various mouth areas by switching between different brushing modes and orientations, enhancing the efficiency of toothbrush operation.

Implementation Method 1

the at least first converter comprises a cam and follower

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP3534824B1An indexed drive system
Publication Date: 2021.09.15 GLAXOSMITHKLINE CONSUMER HEALTHCARE (UK) IP LTD
  • EP3534824B1 patent drawingFigure 1~2
  • EP3534824B1 patent drawingFigure 3~4
  • EP3534824B1 patent drawingFigure 5~6

AI summary

An indexed drive system (10) for mechanised tools, in particular an electric toothbrush, for selectively imparting various drive modes to a pair of concentrically-arranged drive shafts (12, 14) thereby imparting various brushing modes to the head (H) of the mechanised tool, in particular an electric toothbrush.