Electronic Spindle Lock Using Motor Counter-Torque

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Solution Overview

Problem

Conventional power tools with mechanical spindle locks add length, cost, and complexity to the design due to the inclusion of a mechanical component between the power tool drivetrain and the chuck.

Innovation Solution

Implementing an electronic spindle lock system that controls the power tool motor to resist or inhibit movement of the drivetrain by detecting rotation of the bit receiving portion and counter-rotating the motor in the opposite direction, eliminating the need for a mechanical spindle lock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical spindle lock is provided to resist rotation of the drivetrain, then the drivetrain rotation is inhibited, but the device complexity and length increase

Engineering Contradiction:

Improvedrivetrain rotation inhibitionVSAvoidmechanical component complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical spindle lock with an electronic control system that uses the motor controller to detect drivetrain rotation and activate the motor in reverse to counteract the rotation, thereby eliminating the need for a separate mechanical locking component

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The motor controller is given multiple functions: it both controls the motor during normal operation and acts as a spindle lock mechanism by detecting rotation and activating the motor in reverse, consolidating functions that previously required separate components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a mechanical spindle lock is provided to resist rotation of the drivetrain, then the drivetrain rotation is inhibited, but the device length increases

Engineering Contradiction:

Improvedrivetrain rotation inhibitionVSAvoidpower tool length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent combines the spindle lock function with the existing motor and motor controller, merging what were previously separate components into a unified system that uses the motor's bidirectional capability to provide both driving and locking functions

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the motor is controlled to counter-rotate in response to drivetrain rotation detection, then the drivetrain rotation is inhibited, but the energy consumption increases

Engineering Contradiction:

Improvedrivetrain rotation inhibitionVSAvoidmotor energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a control method that periodically monitors drivetrain rotation and activates the motor in reverse only when rotation is detected, rather than continuously operating, thereby reducing overall energy consumption while maintaining effective locking when needed

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses the motor's own bidirectional capability to provide the locking function, eliminating the need for separate locking mechanisms and reducing total system energy consumption by using existing components for multiple purposes

Inventive Principle:

Principle #25Self-service

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

Reduces the overall design length, cost, and complexity of power tools by replacing mechanical spindle locks with an electronic system that maintains a static rotational position and conserves battery life through sleep modes and wake-up signals.

Implementation Method 1

The motor generates a counter torque in response to a torque applied to the bit receiving portion

Methodology Applied

Scientific EffectCounter torque generation: Torque

Implementation Method 2

the rotation of the bit receiving portion in the first direction is detected based on sensing a parameter indicating rotation of the bit receiving portion. the parameter is a rotor position

Methodology Applied

Scientific EffectRotor position sensing: Hall Effect

Data Source

PatentUS12491593B2Electronic spindle lock for a power tool

Publication Date: 2025.12.09 MILWAUKEE ELECTRIC TOOL CORP

AI summary

Electronic spindle lock for a power tool. One embodiment provides a power tool including a housing, a bit receiving portion provided on the housing for receiving a power tool bit, a motor within the housing configured to rotate the bit receiving portion, and a controller coupled to the motor. The controller is configured to enter an electronic spindle lock mode, and detect rotation of the bit receiving portion in a first direction. The controller is also configured to control motor to rotate in a second direction in response to detecting rotation of the bit receiving portion in the first direction.