Electric Drill Dual Braking for Reverse Torque Cutoff

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Solution Overview

Problem

Electric drills face safety hazards due to reverse torque when the drill rod becomes blocked, leading to loss of control and potential damage or breakage, which reduces machine lifespan and operational efficiency.

Innovation Solution

The electric drill incorporates a dual braking system comprising a mechanical clutch and an electronic braking mechanism. The mechanical clutch disengages power transmission when the drill rod encounters resistance, while the electronic braking system, triggered by inertia, stops the motor to prevent counter-torque, ensuring safety and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the power transmission from motor shaft to drill rod is not immediately cut off when drill rod is blocked, then the operator maintains continuous drilling operation, but the large torque causes machine body rebound and loss of control

Engineering Contradiction:
Improvecontinuous drilling operationVSAvoidoperator control
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent replaces the purely mechanical power transmission system with an electromechanical system. The motor shaft is decoupled from the drill rod through electromagnetic control - when blocking is detected, the motor stops rotating while the drill rod can still rotate briefly due to inertia, allowing smooth separation without mechanical shock or rebound to the operator

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

Solution Approach 2:

The patent introduces an intermediary mechanism between the motor shaft and drill rod - a magnetic coupling system that can transmit torque during normal operation but allows decoupling when blocking occurs. This intermediary absorbs the shock and prevents direct transmission of reverse torque to the operator

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the power transmission from motor shaft to drill rod is not immediately cut off when drill rod is blocked, then the drilling operation continues, but the large torque causes drill rod wear or breakage

Engineering Contradiction:
Improvedrilling operation continuityVSAvoiddrill rod durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces direct mechanical coupling with electromagnetic coupling. The motor shaft and drill rod are decoupled through electromagnetic fields, allowing the motor to stop immediately while the drill rod continues rotating briefly due to inertia. This eliminates sudden torque spikes that would cause drill rod wear or breakage

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

Solution Approach 2:

The patent implements a cushioning mechanism in the form of electromagnetic inertia - the drill rod's rotational momentum acts as a buffer between the motor shutdown and complete stop. This gradual deceleration prevents shock loads that would damage the drill rod

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 dual braking system effectively prevents accidents caused by counter-torque, enhances safety, and extends the drill rod's lifespan by preventing damage from sudden torque spikes, maintaining operational efficiency and user control.

Implementation Method 1

a first brake assembly, including: a driving disc, and a driven disc, wherein the driving disc and the driven disc are respectively arranged on the transmission shaft and the output shaft, the driving disc is engaged with the driven disc to transmit power in a non-braking state, and the driving disc and the driven disc are displaced in the axial direction to be separated from each other in a braking state to stop transmitting power

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a second brake assembly, including: a mass block, and a micro switch connected with the motor, wherein in the braking state, the mass block displaces and triggers the micro switch to stop the motor

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP3992417B1Electric drill
Publication Date: 2024.03.13 GLOBE (JIANGSU) CO LTD
  • EP3992417B1 patent drawingFigure 1
  • EP3992417B1 patent drawingFigure 2
  • EP3992417B1 patent drawingFigure 3

AI summary

The disclosure provides an electric drill comprising: a housing; a motor for driving the electric drill to work; an output assembly for outputting the power of the motor; a first brake assembly including a driving disc and a driven disc respectively arranged on the transmission shaft and the output shaft, the driving disc being meshed with the driven disc to transmit power in a non-braking state, and the driving disc and the driven disc being displaced in the axial direction to be separated from each other in a braking state to stop transmitting power; and a second brake assembly including a mass block and a micro switch connected with the motor, and in a braking state, the mass block displacing and triggering the micro switch to stop the motor.