Electric Toothbrush Drive Transmitter Pivot Outside Handle

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Solution Overview

Problem

Existing electric toothbrushes face challenges in achieving efficient cleaning movements with low vibration amplitudes in the lips area while maintaining high cleaning performance, often resulting in unpleasant sensations and drive damping due to complex and costly mechanisms.

Innovation Solution

A toothbrush design with a drive transmitter pivot point shifted outside the handle housing, utilizing a multi-joint suspension like a four-bar linkage with leaf springs, allowing the bristle field to oscillate around a center of motion outside the handle, minimizing lip area movement and maximizing cleaning amplitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a complex gear mechanism with several gear stages and a swash plate is used to convert rotary drive movement into reciprocating cleaning movement, then the cleaning movement can be achieved, but the structure becomes bulky and integration into a slim toothbrush body is hardly possible

Engineering Contradiction:
Improveintegration into slim toothbrush bodyVSAvoidgear mechanism with several gear stages and swash plate
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts the swash plate mechanism from the traditional gear train and uses it directly as the drive transmitter. This single swash plate replaces multiple gear stages, converting rotary motion to reciprocating motion in one element rather than through a complex multi-stage gear mechanism, thereby achieving a compact design that integrates easily into a slim toothbrush body

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of multiple gear stages and the swash plate into a single integrated drive system. The swash plate simultaneously performs motion conversion and transmission, combining what were previously separate components into one unified mechanism, reducing overall complexity and size

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the drive transmitter is mounted inside the handle housing, then the structure is compact, but the transverse movement occurs not only on the bristle field but also in the area of the brush tube, leading to unpleasant sensation for the user and undesired drive damping

Engineering Contradiction:
Improvecleaning movement amplitudeVSAvoidunpleasant sensation in lips area and drive damping
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent positions the swash plate's large end outside the handle housing, extending the drive transmitter beyond the traditional mounting location. This spatial reconfiguration allows the reciprocating motion to be concentrated at the bristle field while minimizing movement in the handle and lips area, effectively separating the useful motion from harmful vibrations

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

Solution Approach 2:

The patent creates different motion characteristics in different regions: large amplitude reciprocating motion at the bristle field for effective cleaning, and minimal motion in the handle and lips area to avoid unpleasant sensations. The swash plate geometry and positioning enable this localized differentiation of motion quality

Inventive Principle:
Principle #3Local quality

3Reliability

If bearings such as ball bearings are used to mount the drive transmitter, then the mounting is stable, but the structure becomes complicated and expensive and often leads to unpleasant noises and motor damping

Engineering Contradiction:
Improvemounting stabilityVSAvoidbearing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces expensive, complex bearings with a simple, inexpensive bushing made of friction-reducing material. This substitute component achieves sufficient mounting stability without the complexity and cost of precision bearings, and without causing unpleasant noises or motor damping

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the mechanical bearing system with a bushing-based mounting. Instead of using rolling element bearings or other complex mechanical mounting solutions, the drive transmitter is simply inserted into and mounted within the bushing, which provides adequate support with minimal friction

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

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

This design achieves efficient cleaning with large amplitudes in the bristle field and low vibrations in the lips area, reducing manufacturing costs and avoiding damping issues, while allowing for adjustable operating modes and independent control of frequency and amplitude.

Implementation Method 1

an electromechanical actuator, which in particular is designed as a magnetic oscillation motor, is provided for moving the drive transmitter

Methodology Applied
Scientific EffectElectromagnetic drive: Electromagnetic Induction

Implementation Method 2

the actuator directly generates linear drive movement which is transmitted to the drive transmitter; the actuator is designed as a magnetic oscillation motor

Methodology Applied
Scientific EffectMagnetic oscillation: Magnetic Field

Data Source

PatentEP2160148B1Electric toothbrush
Publication Date: 2018.12.26 BRAUN GMBH
  • EP2160148B1 patent drawingFigure 1
  • EP2160148B1 patent drawingFigure 2~3
  • EP2160148B1 patent drawingFigure 4

AI summary

The present invention relates to an electric toothbrush, specifically the toothbrush handle of an electric toothbrush, with a handle housing, with a preferably rod-shaped drive transmitter which protrudes from a first side of the handle housing and on which a brush attachment can be secured, and with a drive motor for moving the drive transmitter, wherein the drive transmitter is mounted, by means of a bearing device in the interior of the handle housing, in the manner of a rocker arm such that the drive transmitter can be pivoted to and fro transverse to its longitudinal axis by the drive motor. The invention further relates to the whole toothbrush, comprising such a toothbrush handle part and a brush attachment secured to the drive transmitter thereof. According to the invention, the bearing device holds the drive transmitter so as to pivot about a rotation point lying outside the handle housing. Said rotation point is offset particularly far out from the handle housing, such that it comes to lie between the bristle array of the brush attachment and the front end of the handle in the area of the lips. In this way, an efficient cleaning movement with a large cleaning range in the area of the bristle array can be combined with a low vibration amplitude of the toothbrush in the area of the lips.