Handheld Appliance Handle Sensing for Intuitive Motor Power Control
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Solution Overview
Problem
Existing hand-held domestic appliances with power adjustment functions, such as kitchen and personal grooming devices, often use non-intuitive controls like knobs and rotary switches, which occupy space and may not be suitable for users with varying hand strength and size, and pressure input devices may not provide a universal intuitive interface.
Innovation Solution
A hand-held domestic appliance with a surface sensor in the handle part that detects contact surface area and pressure, allowing the controller to adjust motor power accordingly, enabling intuitive power control without physical movement of a control button, and allowing user-defined calibration for personalized settings and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If knobs and rotary switches are used for power control, then power adjustment function is achieved, but the control occupies large space and limits design freedom
Solution Approach 1:
The patent replaces mechanical control elements (knobs, rotary switches, pressure pads) with a capacitive touch sensor system. The controller detects changes in capacitance value caused by finger proximity or contact to determine user intent for power adjustment, eliminating the need for physical control components and their associated mechanical movement.
Solution Approach 2:
The patent introduces capacitance detection as an intermediary between user input and motor control. Instead of direct mechanical interaction, the system uses electrical field changes (capacitance variations) caused by the user's finger to mediate the control signal, enabling contactless or minimal-contact operation.
2Ease of operation
If pressure pad is used for motor speed control, then power adjustment is enabled, but users with different hand strength find it non-intuitive
Solution Approach 1:
The patent changes the control parameter from pressure force to capacitance value. Instead of requiring users to apply different forces (which varies by hand strength), the system detects capacitance changes caused by finger proximity or contact area, providing a more universal interface that adapts to different users without requiring force calibration.
Solution Approach 2:
The patent replaces the mechanical pressure sensing system with an electrical field-based capacitive detection system. This substitution eliminates the need for mechanical force application and provides a more intuitive control method that naturally adapts to different users' hand characteristics.
3Ease of operation
If surface sensor detects contact surface area, then intuitive power control is achieved, but additional sensor complexity is introduced
Solution Approach 1:
The patent makes the capacitive sensor serve multiple functions: it detects both the presence of a finger (for basic on/off control) and the contact area or pressure (for power level adjustment). This multi-functionality reduces the need for separate sensors for different control aspects, thereby reducing overall system complexity despite the advanced capabilities.
Solution Approach 2:
The patent utilizes different parameters from the same capacitive sensor (capacitance value, contact area, pressure) to achieve multiple control functions. By extracting different information from the same sensor based on varying physical parameters, the system avoids adding multiple sensors while providing intuitive power control.
4Power
If pressure control is implemented, then motor power can be increased by pressing harder, but safety concerns arise for infants and children
Solution Approach 1:
The patent implements feedback by continuously monitoring capacitance values and comparing them against predetermined thresholds. The controller adjusts motor power based on the detected capacitance level, and can prevent operation entirely if the detected contact does not meet the minimum threshold, thereby providing safety against unintended activation by infants or children while still allowing full power control for legitimate users.
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
Provides a more intuitive and adaptable control mechanism that suits different users, enhances safety by preventing operation by children and the elderly, and allows for comfortable and efficient power adjustment without the need for significant force, while offering design flexibility and space-saving benefits.
Implementation Method 1
the handle part comprises a surface sensor for detecting a contact surface area
Implementation Method 2
The surface sensor may additionally be for detecting a pressure
Data Source
AI summary
A hand held domestic appliance comprises a handle part, a driven member, a motor for driving the driven member and a controller for controlling the motor. The handle part comprises a surface sensor for detecting a contact surface area and optionally also pressure and the controller is adapted to control the power supplied to the motor in dependence on the sensed contact surface area and optionally also pressure.