Power Tool User Interface With Hall-Effect Sensors

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Solution Overview

Problem

Existing power tool user interfaces often lack efficient mechanisms for selecting operation modes and providing feedback, especially in dynamic control scenarios, such as when using work gloves, and may have complex internal wiring and additional PCBs that increase complexity and vulnerability to vibrations.

Innovation Solution

A hand-held power tool design featuring a user interface with a control knob, Hall-effect sensors, and magnet-based sensor actuators or a potentiometer with a plunger, integrated into a printed circuit board (PCB) that allows for contactless detection of mode positions, reducing internal wiring and enhancing vibration resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional switches or knobs with physical contact are used for mode selection, then the control mechanism is simple and reliable, but the internal wiring becomes complex and the system becomes more vulnerable to vibrations

Engineering Contradiction:
Improvevibration resistanceVSAvoidinternal wiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical contact-based switches and knobs with a magnetic field-based detection system. Hall-effect sensors detect the position of a control element (such as a rotary dial or switch) by sensing changes in magnetic field strength caused by magnets attached to the moving component. This eliminates the need for physical contact and complex internal wiring, reducing vulnerability to vibrations while maintaining control functionality.

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

Solution Approach 2:

The patent introduces magnets as an intermediary between the control element and the Hall-effect sensors. The magnets create a magnetic field that serves as the medium for transmitting position information to the sensors without requiring direct physical contact or electrical connection. This intermediary approach simplifies the internal wiring structure while maintaining reliable position detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If multiple separate PCBs are used for control functions, then each PCB can be optimized for its specific function, but the overall device complexity increases and internal wiring becomes more complex

Engineering Contradiction:
Improvefunctional optimizationVSAvoidnumber of PCBs
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple control functions onto a single PCB by integrating Hall-effect sensors directly into the board. This consolidation eliminates the need for multiple separate PCBs and their associated wiring, simplifying the overall device structure while maintaining the ability to perform multiple control functions through software or circuit design on the unified PCB.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If contact-based sensors are used for position detection, then the detection mechanism is simple, but the system becomes more vulnerable to vibrations and wear

Engineering Contradiction:
Improvedetection stabilityVSAvoidvibration sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces contact-based position detection sensors with Hall-effect sensors that operate on magnetic field principles. These sensors have no moving parts or physical contact points, making them inherently resistant to vibration and wear. The sensors detect position by measuring changes in magnetic field strength, providing stable and reliable detection without the vulnerabilities associated with mechanical contact systems.

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

The solution enables intuitive mode selection and feedback, reduces internal complexity, and improves vibration resistance by integrating sensors and actuators directly into the PCB, allowing for efficient operation mode control and enhanced durability.

Implementation Method 1

The plurality of sensors being Hall-effect sensors; the one or more sensor actuators are at least one magnet, wherein the at least one magnet is selectively locatable adjacent one of the plurality of Hall-effect sensors

Methodology Applied
Scientific EffectHall-effect: Hall Effect

Data Source

PatentEP3302891B1Power tool user interfaces
Publication Date: 2020.11.04 INGERSOLL RAND IND US INC
  • EP3302891B1 patent drawingFigure 1~2
  • EP3302891B1 patent drawingFigure 3
  • EP3302891B1 patent drawingFigure 4~5

AI summary

A hand-held power tool is provided that includes a motive source, a user interface, and one or more sensors. The motive source includes a printed circuit board (PCB) configured to support electrical components of the motive source. The user interface is movable between a plurality of mode positions to select one of a plurality of operational modes of the motive source. And one or more sensors are mounted on the PCB and are configured to detect the plurality of mode positions of the user interface.