Power Tool Orientation Sensor Using Accelerometer Gyroscope

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Solution Overview

Problem

Existing power tools lack an accurate and reliable method to indicate whether they are level, plumb, or perpendicular to a workpiece, relying on user perception and inaccurate methods such as bubble levels and lights.

Innovation Solution

A power tool system utilizing sensors, including accelerometers and gyroscopes, to determine the orientation of the tool axis relative to a workpiece, with a control circuit and indicator lights to provide real-time feedback on alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If bubble levels or simple lights are used to indicate orientation, then the device complexity is reduced, but the measurement precision and reliability deteriorate

Engineering Contradiction:
Improveindicator system complexityVSAvoidorientation indication accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical bubble levels with electronic sensors (accelerometers and gyroscopes) that electronically detect orientation. This substitution provides more precise measurements while maintaining reasonable device complexity through integrated sensor modules and digital processing circuits.

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

Solution Approach 2:

The patent introduces light guides as intermediaries between the sensors and the indicator lights. The light guides transmit light signals from the indicator lights to the user's eye, enabling accurate visual feedback on orientation without requiring complex direct display mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If bubble levels are used to indicate orientation, then the device complexity is reduced, but the ease of operation deteriorates due to difficulty in visualization

Engineering Contradiction:
Improveindicator system complexityVSAvoiduser perception difficulty
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent uses different colored indicator lights (e.g., green for level, red for not level) to provide intuitive visual feedback on tool orientation. This color-coding system makes it immediately obvious to the user whether the tool is properly oriented, significantly improving ease of operation.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The light guides serve as intermediaries that channel and focus light from the indicators to the user's field of view, making the orientation status clearly visible without requiring the user to focus on small or dim indicators.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple sensors are added to improve orientation detection accuracy, then the measurement precision improves, but the device complexity increases

Engineering Contradiction:
Improveorientation detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensors (accelerometers and gyroscopes) into an integrated sensor system that works together to detect orientation. By merging these sensors and processing their outputs through a unified control circuit, the system achieves high measurement precision while managing device complexity through integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor system is designed to perform multiple functions: detecting tilt angle, determining level/plumb status, and providing feedback for different operating modes. This multi-functionality reduces the need for separate specialized components, managing complexity while maintaining precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 provides an automated and accurate way for users to determine the orientation of the power tool, reducing errors and improving precision in various operating modes, including vertical, horizontal, and angled operations.

Implementation Method 1

The one or more motion sensors may include one or more accelerometers to sense acceleration of the tool housing. There may be three accelerometers arranged along orthogonal axes. The acceleration due to gravity in each direction may be used to determine whether the tool is level, plumb, or perpendicular.

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

In addition or in the alternative, the one or more motion sensors may additionally include one or more gyroscopic sensors to sense rotational movement of the tool housing. There may be three gyroscopic sensors arranged about three orthogonal axes.

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 3

The indicator may include an array of LEDs. The array may include a left light and a right light to indicate when the tool axis is angled in a left or right direction relative to the workpiece.

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Data Source

PatentEP2679348B1Level, plumb and perpendicularity indicator for power tool
Publication Date: 2020.07.29 BLACK & DECKER CORP
  • EP2679348B1 patent drawingFigure 1
  • EP2679348B1 patent drawingFigure 2
  • EP2679348B1 patent drawingFigure 3A

AI summary

A power tool includes a housing, an output shaft having a tool axis, and a motion sensor that senses motion of the tool housing. A control circuit receives an input signal from the motion sensor, to make a first determination, based on the input signal, whether the tool is being operated in a horizontal mode or a vertical mode. The control circuit makes a second determination, based on the input signal, whether the tool axis is substantially level when the tool is being operated in the horizontal mode or the tool axis is substantially plumb when the tool is being operated in the vertical mode. An indicator receives an output signal from the control circuit that causes the indicator to indicate whether the tool axis is level when being operated in the horizontal mode or plumb when being operated in the vertical mode.