Handheld Motor Control Using Handle Load Sensing for Kickback Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing handheld electric work machines face challenges in detecting whether a side handle is gripped by a user, leading to potential kickback issues due to complex signal transmission paths and device configurations.

Innovation Solution

A handheld electric work machine with a handle that is fixed or detachably attached to the housing, equipped with multiple measurement devices to measure loads, and a control circuit that adjusts electric power based on these loads to detect handle grip and prevent kickback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a detection unit is provided on the side handle to detect grip state, then the kickback can be reduced, but the device configuration becomes more complicated due to the need for signal transmission path

Engineering Contradiction:

Improvekickback reductionVSAvoiddevice configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the detection function into the existing load measurement system by utilizing the imbalance of loads on multiple measurement devices when the handle is gripped. This eliminates the need for a separate detection unit and its signal transmission path, thus resolving the contradiction between reliability improvement and device complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Difficulty of detecting and measuring

If multiple measurement devices are used to measure loads, then the handle grip state can be detected, but the device configuration becomes more complicated

Engineering Contradiction:

Improvehandle grip detectionVSAvoiddevice configuration

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent makes the load measurement devices serve dual purposes: they both measure the loads for motor control and simultaneously detect the handle grip state through load imbalance. This multi-functionality eliminates the need for separate detection devices, resolving the contradiction between detection capability and device complexity.

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 solution simplifies the device configuration by eliminating the need for separate measurement devices and signal paths, effectively detecting handle grip and reducing kickback through power adjustments.

Implementation Method 1

Two or more measurement devices (i) receive two or more loads from the handle fixed or attached to the housing, and also (ii) measure the two or more loads received

Methodology Applied

Scientific EffectLoad measurement:

Data Source

PatentUS12576469B2Technique for controlling motor in handheld electric work machine

Publication Date: 2026.03.17 MAKITA CORP

AI summary

One aspect of the present disclosure provides an electric work machine including a motor, a motor driver, an output shaft, a housing, two or more measurement devices, and a control circuit. The housing includes a handle fixed thereto or is configured such that the handle is detachably attached thereto. The two or more measurement devices (i) receive two or more loads from the handle fixed or attached to the housing, and also (ii) measure the two or more loads received. The control circuit adjusts a magnitude of the electric power, based on the two or more loads measured.