Accelerometer Motor Speed Control for Trigger-Free Handheld Tools

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Solution Overview

Problem

Handheld motorized devices, such as weed trimmers and leaf blowers, require users to simultaneously support the device and depress a trigger to control speed and direction, leading to muscle fatigue and reduced dexterity due to the need for precise finger control.

Innovation Solution

The use of an accelerometer to sense the attitude orientation of the device, allowing the user to control the motor speed and direction by manipulating the device's orientation, thereby eliminating the need for a trigger mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a trigger mechanism is used to control motor speed and direction, then precise control is achieved, but the user experiences muscle fatigue and reduced dexterity due to prolonged finger manipulation

Engineering Contradiction:

Improvecontrol precisionVSAvoiduser comfort

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical trigger system with an accelerometer-based sensing system. The accelerometer detects device orientation and acceleration to automatically control motor speed and direction, eliminating the need for continuous mechanical trigger manipulation by the user's finger.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The device uses the user's natural manipulation of the device orientation to control motor functions. The accelerometer senses the device's attitude and automatically adjusts motor parameters, allowing the device to serve itself rather than requiring separate trigger control.

Inventive Principle:

Principle #25Self-service

2Ease of operation

If ergonomic improvements are made to reduce finger strain, then user comfort is improved, but device complexity and cost increase due to additional mechanisms

Engineering Contradiction:

Improveuser comfortVSAvoidmechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The accelerometer serves multiple functions: it detects device orientation for speed control, determines direction of movement, and can trigger operational modes. This multi-functionality eliminates the need for separate ergonomic mechanisms while achieving comprehensive control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces complex mechanical ergonomic solutions (such as trigger locks or assisted trigger mechanisms) with an electronic accelerometer-based system that uses the device's natural movement and orientation to control motor functions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the entire hand is used to control device orientation, then ergonomics are improved, but the ability to precisely manipulate a trigger with the same hand is reduced

Engineering Contradiction:

Improvehand utilizationVSAvoidcontrol precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The mechanical trigger system is replaced with an accelerometer that senses device orientation and movement. This allows the user's entire hand to manipulate the device naturally while the accelerometer precisely measures the device's attitude to control motor speed and direction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The accelerometer acts as an intermediary between the user's hand manipulation and the motor control system. It translates the device's orientation and acceleration into precise motor commands, bridging the gap between natural hand movement and precise control requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This solution improves ergonomics by allowing full-hand control of the device, reduces the risk of injury and muscle fatigue, and enhances reliability by replacing complex trigger mechanisms with a simpler accelerometer-based system, while also reducing costs.

Implementation Method 1

utilize an accelerometer as a sensor to sense the resulting attitude orientation of the device that is already being manipulated by the user's hand

Methodology Applied

Scientific EffectAccelerometer: Accelerometer

Data Source

PatentUS20250167698A1Accelerometer Controlled Rotating Motor Speed System and Method of Operation

Publication Date: 2025.05.22 ROBICHAUX NURCAN

AI summary

The system of has one accelerometer, one motor, one signal processor, one electronic motor speed controller, a power switch, a power source, a housing and a handle. The user controls the attitude orientation of the device by manipulating the handle. The accelerometer is connected to the housing or handle, and detects the acceleration due to gravity in at least one axis of the housing or the handle. The accelerometer communicates with the signal processor. The signal processor determines a commanded operating motor speed based on a preprogrammed schedule of one or more accelerometer output signals and sends the commanded operating motor speed to an electronic motor speed controller. The electronic motor speed controller controls the speed and direction of the motor according to the commanded speed and direction of the signal processor. The power switch activate the device based on the switch ON/OFF position.