Electric Toothbrush Oval Bristle Motion

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Solution Overview

Problem

Aging populations are prone to gum recession and tooth decay due to food particles being swept under the gums during regular tooth brushing, leading to bacterial proliferation and cavities.

Innovation Solution

An electric toothbrush with an orientation sensor and power transmission assembly that automatically adjusts the bristle movement to trace an oval path, ensuring bristles move away from the gums and along the teeth surface, reducing the likelihood of food particles being trapped.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If normal brushing is used to clean teeth, then teeth are cleaned effectively, but food particles are swept under the gums causing tooth decay

Engineering Contradiction:
Improvebrushing effectivenessVSAvoidfood particles under gums
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the traditional brushing motion by making the brush head move in an oval path rather than moving the brush along the teeth. The bristle holder moves relative to the stationary brush head, reversing who moves and how, to prevent food particles from being swept under the gums

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

Solution Approach 2:

The patent introduces dynamic motion control through a power transmission assembly that generates an oval path of the bristle holder. The motion transitions from static or simple linear movement to a complex oval trajectory with varying speed and direction, optimizing the brushing action to prevent food particle entrapment

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If an oval path motion is implemented, then food particles are prevented from entering under gums, but device complexity increases

Engineering Contradiction:
Improvefood particles under gumsVSAvoidpower transmission assembly
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical linkages with a magnetic coupling system. Magnets in the drive assembly magnetically couple with corresponding magnets in the brush head to transmit rotational motion without direct mechanical connection, simplifying the overall mechanical structure while achieving the desired oval path motion

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the drive assembly and the brush head. The magnetic coupling acts as a mediator to transmit power and motion, eliminating the need for direct mechanical contact and reducing structural complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If bristle holder moves relative to brush head, then optimal brushing path is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvebrushing efficiencyVSAvoidoval path accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the motion parameters by varying the speed of rotation during the oval path traversal. The brush head rotates at different speeds during different phases of the oval path, allowing for optimized brushing action while compensating for manufacturing tolerances through dynamic parameter adjustment

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

Effectively reduces the incidence of tooth decay by ensuring thorough brushing while preventing food particles from being swept under the gums, thus addressing the specific brushing challenges faced by the aging demographic.

Implementation Method 1

the camming element executes a motion that is eccentric relative to a power transmission axis

Methodology Applied
Scientific EffectEccentric motion: Eccentric

Implementation Method 2

The sensor may take the form of a ball sensor. The ball completes a circuit including two of four contact pins provided in the toothbrush frame. Alternatively, the sensor includes a gravity switch or accelerometer.

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3191014B1Electric toothbrush module
Publication Date: 2020.10.07 J T LABS LTD
  • EP3191014B1 patent drawingFigure 1
  • EP3191014B1 patent drawingFigure 2
  • EP3191014B1 patent drawingFigure 3

AI summary

A toothbrush has a frame, a bristle holder movably mounted to a distal end of the frame, and a power transmission assembly operatively connectable to a drive motor and operatively connected to the bristle holder so as to move bristle tips on the bristle holder along an oval path relative to the frame. In a single cycle of movement along the oval path, the bristles shift away from the frame and towards the teeth, then along and in contact with the teeth in a direction away from the gum line, then back towards the frame and away from the teeth, and subsequently along the frame and out of contact with the teeth.