High-Modulus Connector for Grip-Independent Brush Vibration

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Solution Overview

Problem

Existing electrically operated personal care implements, such as toothbrushes, suffer from vibration performance that is highly dependent on user grip and are hindered by bulky neck designs that compromise maneuverability and reachability, especially when motors are located within the handle or neck.

Innovation Solution

A handle design with a connector made from a material with a higher modulus than the handle housing, accommodating a motor with an eccentric weight in close proximity, allowing for efficient vibration transmission and a slim, curved neck design through a connector-to-handle ratio of 2.5 to 4.5, using fiber-reinforced materials for durability and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the motor is located within the handle housing, then the vibrations can be transmitted to the head, but the amplitude of vibrations at the brush head depends on user grip and vibrations are significantly damped when held tightly

Engineering Contradiction:
Improvevibration amplitudeVSAvoiduser grip dependency
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The motor is extracted from the handle housing and relocated to the connector, which directly interfaces with the brush head. This extraction removes the motor from the user's grip zone, eliminating the damping effect of hand pressure on vibration transmission while maintaining effective vibration delivery to the bristles.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The connector serves as an intermediary structure between the motor and the brush head, providing a rigid transmission path for vibrations. By making the connector from material with higher e-modulus than the handle housing, it acts as a stiff mediator that transmits motor vibrations directly to the head without being affected by grip forces on the handle.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the motor is located within the neck of the toothbrush head, then the vibrations can be directly transmitted to the head, but the neck becomes bulky and large in cross section which impedes maneuverability and reachability

Engineering Contradiction:
Improvevibration transmission efficiencyVSAvoidneck cross section
Core Design Contradiction:
PowerVSLength of moving object

Solution Approach 1:

The motor is taken out from the brush head neck and relocated to the connector in the handle. This removes the bulky motor housing from the neck area, allowing the neck to maintain a slim, curved profile that provides excellent maneuverability and reachability to back molars while the motor remains positioned to efficiently drive the brush head.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If a chassis is embedded inside the handle housing to mount the motor, then the motor can be securely mounted, but the additional chassis-housing interface absorbs vibrations which leads to losses of vibration energy

Engineering Contradiction:
Improvemotor mounting stabilityVSAvoidvibration energy loss
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The motor mounting interface is extracted from the handle housing by relocating the motor to the connector. This eliminates the intermediate chassis-housing interface that was absorbing vibration energy, creating a direct vibration path from motor to brush head while the connector's rigid material provides sufficient mounting stability.

Inventive Principle:
Principle #2Taking out (Extraction)

4Power

If the connector is made from material with higher e-modulus than the handle housing, then the vibrations are transmitted more efficiently, but the connector becomes stiffer which may affect absorption of impact forces

Engineering Contradiction:
Improvevibration transmission efficiencyVSAvoidimpact force absorption
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The connector is designed with local quality by using high e-modulus material specifically in the vibration transmission path from motor to brush head, while the handle housing uses materials optimized for comfort and impact absorption. This localized material selection allows efficient vibration transmission where needed without compromising overall impact resistance of the handle.

Inventive Principle:
Principle #3Local quality

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

Enhances in-mouth perception and cleaning performance by ensuring consistent vibration amplitude regardless of grip and allows for superior maneuverability and reachability of back molars with a durable, cost-effective, and environmentally friendly design.

Implementation Method 1

a motor for operating the assembly, the motor comprising an eccentric weight

Methodology Applied
Scientific EffectEccentric weight: Eccentric

Implementation Method 2

The motor vibrates the entire handle and therewith also the brush head that is attached to the handle

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP4215155B1An electrically operated assembly and electrically operated personal care implement
Publication Date: 2025.07.16 THE GILLETTE CO
  • EP4215155B1 patent drawingFigure 1~2
  • EP4215155B1 patent drawingFigure 3
  • EP4215155B1 patent drawingFigure 4

AI summary

An electrically operated assembly comprises a handle housing, a connector for repeatably attaching and detaching a head to and from the assembly, the connector being in direct proximity to a motor for operating the assembly, the motor comprising an eccentric weight, wherein the connector is made from a material having an e-modulus being higher than the e-modulus of the material from which the handle housing is made, and a ratio between an overall length extension of the handle housing extending along a longitudinal housing axis and an overall length extension of the connector extending along a longitudinal connector axis is from about 2.5 to about 4.5, preferably from about 3.0 to about 3.5.