Cord clamp current sensor for dust collector

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Solution Overview

Problem

Existing dust collection systems require users to disconnect power tools from the source and connect them to a special-purpose socket, adding cost and inconvenience, and limiting current handling capacity.

Innovation Solution

A dust collection system using a clamp sensor that snaps around the power tool's cord to measure current flow, eliminating the need for a special-purpose socket and allowing the power tool to be plugged into a separate electrical outlet, with a detection circuit that turns on the dust collector motor when current exceeds a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a special-purpose socket is used to connect power tool to dust collector, then current measurement is enabled, but device complexity and cost increase

Engineering Contradiction:
Improvecurrent measurement capabilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The current measurement function is extracted from the dust collector and implemented as a separate clamp-on sensor that can be independently attached to the power cord. This separates the measurement capability from the main dust collector unit, reducing its complexity while maintaining measurement functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A clamp-on current sensor acts as an intermediary device between the power cord and the dust collector control system. It measures current through the cord and transmits signals to the dust collector, enabling current-based control without requiring a special socket integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If power tool is connected to dust collector via special socket, then dust collection is enabled, but current handling capacity is limited

Engineering Contradiction:
Improvedust collection functionalityVSAvoidcurrent handling capacity
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The dust collection system is decoupled from the power tool connection. The dust collector operates independently based on current detection signals from the clamp sensor, allowing the power tool to draw power from any outlet without being constrained by the dust collector's socket current rating.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The clamp-on current sensor serves as an intermediary that monitors power consumption without being part of the power transmission path. This allows the system to detect when the power tool is operating and activate the dust collector accordingly, without the physical connection limiting current capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If AC line splitter with current transformer is used, then current measurement is achieved, but ease of operation deteriorates

Engineering Contradiction:
Improvecurrent measurement capabilityVSAvoiduser convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The clamp-on current sensor acts as a convenient intermediary that can be quickly attached to or removed from the power cord without requiring electrical connections or modifications to the outlet. This maintains ease of operation while enabling current measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical connection requirement of AC line splitters is replaced with a magnetic field-based measurement approach. The clamp sensor measures current through electromagnetic induction around the conductor, eliminating the need for physical disconnection and reconnection of electrical outlets.

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

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

Enables cost-effective and convenient dust collection by allowing the power tool to operate on a higher current branch circuit without the need for a special socket, improving user convenience and current handling capacity.

Implementation Method 1

The electromagnetic element senses current flow in the cord

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2777464B1Cord clamp current sensor for dust collector
Publication Date: 2021.07.28 BLACK & DECKER CORP
  • EP2777464B1 patent drawingFigure 1A~1B
  • EP2777464B1 patent drawingFigure 2A
  • EP2777464B1 patent drawingFigure 2B

AI summary

A dust collection system includes a sensor body, a selection circuit, a detection circuit, and a motor control circuit. The sensor body detachably encircles a cord supplying power to a power tool. The cord includes a neutral conductor and a hot conductor. The sensor body houses sensors that, in response to current flow through the cord, generate sensor signals. The selection circuit generates a positive output signal in response to the sensor signals and generates a negative output signal in response to the sensor signals. The detection circuit generates a current detection signal in response to a comparison of the positive and negative output signals with a threshold. The motor control circuit selectively turns on a motor of the dust collection system in response to the current detection signal.