Toothbrush Motor Current Sensing for Gum Pressure Control

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Solution Overview

Problem

Conventional electronically driven toothbrushes lack the ability to monitor and adjust the pressure exerted on the gums, which can lead to potential damage due to user-applied force combined with the stiffness and electronic movement of the bristles.

Innovation Solution

A toothbrush system with a pressure sensing function that includes a sensing module to monitor the current draw of a direct current motor, allowing for dynamic adjustment of the motor's power to maintain a safe pressure level, and providing alerts or adjustments when excessive force is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If electronically driven toothbrushes provide superior cleaning capabilities through motor-driven brush head oscillation, then cleaning effectiveness is improved, but user-applied force combined with bristle stiffness can damage gums

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidgum damage from excessive pressure

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system monitors motor current draw in real-time to detect pressure applied by the user. When excessive pressure is detected (indicated by current exceeding a threshold), the system provides feedback to the user through haptic alerts or visual indicators, prompting them to reduce pressure. This closed-loop feedback mechanism prevents gum damage while maintaining effective cleaning.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical pressure sensing with an electrical sensing approach. Instead of using mechanical pressure sensors that would require physical contact with the brush head, the system uses the motor's electrical characteristics (current draw) to infer the pressure being applied. This substitution simplifies the system architecture and enables pressure monitoring without additional mechanical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If the toothbrush includes pressure sensing and dynamic adjustment capabilities, then gum safety is improved, but device complexity increases

Engineering Contradiction:

Improvegum safetyVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system uses the motor's own electrical characteristics (current draw) as the sensing mechanism. The motor serves dual purposes: driving the brush head and providing pressure information through its electrical consumption. This self-service approach eliminates the need for separate pressure sensing components, reducing overall system complexity while maintaining gum safety monitoring capabilities.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The motor is given multiple functions: it drives the brush head oscillation for cleaning and simultaneously serves as a pressure sensor through its current draw characteristics. This multi-functionality reduces the number of components needed in the system, as the same component (motor) performs both actuation and sensing roles, thereby reducing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If the motor control dynamically adjusts current based on detected pressure, then pressure control precision is improved, but energy consumption increases

Engineering Contradiction:

Improvepressure control precisionVSAvoidmotor energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system continuously monitors motor current and dynamically adjusts power delivery in real-time based on detected pressure conditions. This periodic control ensures precise pressure management by constantly adapting motor output to actual brushing conditions, preventing both excessive pressure and inefficient energy usage during light-contact periods.

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 system effectively prevents excessive pressure on the gums by dynamically adjusting the motor's operation, ensuring a safe and effective cleaning experience while accommodating changes in brush wear and user interaction.

Implementation Method 1

a sensing module that detects a current provided to the motor

Methodology Applied

Scientific EffectElectrical current measurement: Ohmmeter

Implementation Method 2

a motor control coupled to the motor and the sensing module, wherein the motor control dynamically adjusts a current provided to the motor based on the detected current

Methodology Applied

Scientific EffectElectrical current control: Electrical Resistance

Data Source

PatentUS10561480B2Load sensing for oral devices

Publication Date: 2020.02.18 WATER PIK INC

AI summary

A toothbrush is disclosed. The toothbrush includes a handle, a brush tip connected to the handle, wherein the brush tip includes a plurality of bristles operably connected thereto, a power source, a direct current motor in selective electrical communication with the power source, wherein the motor includes a drive shaft, a drive assembly connected between the brush tip and the drive shaft, wherein the drive assembly converts rotation of the drive shaft into movement of the plurality of bristles, and a control assembly in electrical communication with the motor and the power source; wherein during operation of the motor, the control assembly monitors a current draw by the motor and adjusts a current applied to the direct current motor based on the current draw.