Electromagnetic Roller Conveyor for Continuous Weight Sorting

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Solution Overview

Problem

Conventional checkweighers in production lines require stopping and gapping of conveyor belts for accurate weight measurements, which slows down production and is inefficient for continuous weighing of multiple cases.

Innovation Solution

A conveyor system with electromagnetically activated rollers that divert articles based on weight by using a linear-induction motor to rotate rollers perpendicular to the belt direction, allowing for continuous operation and sorting of objects without stopping, using a side rail to guide diverted objects and sensors to measure lateral displacement for weight determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional checkweighers are used to weigh cases, then accurate weight measurements can be obtained, but the production line must be stopped and cases must be gapped, which slows down production

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidproduction throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the traditional mechanical stopping and gapping system with an electromagnetic roller propulsion system. The rollers use electromagnetic induction to propel cases laterally off the main conveyor based on their weight, eliminating the need to stop the production line for weighing. This substitution maintains measurement accuracy while preserving continuous production flow.

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

Solution Approach 2:

The patent introduces electromagnetic rollers as an intermediary mechanism between the main conveyor and the weighing/sorting function. These rollers act as a mediator that can selectively propel cases based on weight without interrupting the main conveyor's continuous operation, thus resolving the contradiction between accurate measurement and continuous production.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If cases are separated by gaps or stopped for weighing, then accurate weight measurement is possible, but production efficiency decreases

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidproduction time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables continuous weighing and sorting operation by keeping the main conveyor in constant motion. The electromagnetic rollers provide continuous lateral propulsion to selected cases based on their weight, allowing the weighing and sorting function to operate continuously without stopping or gapping cases, thus eliminating time loss while maintaining measurement accuracy.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If multiple cases are weighed consecutively with stopping and gapping, then each case can be measured accurately, but the overall production speed decreases

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidconveyor speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent introduces dynamic control through electromagnetic rollers that can be activated selectively and continuously along the conveyor. This dynamic system allows different cases to be propelled at different times and positions based on their weight, enabling accurate measurement of multiple consecutive cases while maintaining constant conveyor speed and overall production flow.

Inventive Principle:
Principle #15Dynamics

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 continuous and efficient weight-based quality control by sorting objects based on weight without interrupting the production line, allowing for accurate measurement and rejection of non-conforming items while maintaining high production throughput.

Implementation Method 1

WO 2013/169343 discloses conveyor rollers rotated by electromagnetic induction to propel articles conveyed atop the rollers

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The traveling flux wave induces eddy currents in the electrically conductive material of the rollers 14. The currents produce a reaction magnetic field that interacts with the stator flux wave to cause a constant torque in the rollers 14

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

The currents produce a reaction magnetic field that interacts with the stator flux wave to cause a constant torque in the rollers 14

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP3302830B1LIM weight sorter
Publication Date: 2020.10.21 LAITRAM LLC
  • EP3302830B1 patent drawingFigure 1~6B
  • EP3302830B1 patent drawingFigure 2A~2D
  • EP3302830B1 patent drawingFigure 3A~3D

AI summary

A conveyor and a method for weighing conveyed objects or sorting them by weight. The conveyor comprises a conveyor belt having electrically conductive rollers that are rotated with a constant torque in a lateral direction by a linier-induction stator defining a roller-activation zone along a carryway. Because the lateral acceleration of a conveyed object is inversely proportional to the object's weight, lighter objects are displaced laterally farther and at greater speeds than heavier objects. So their weights can be determined from the lateral acceleration, speed, or displacement. And objects can be sorted off the side of the belt by weight.