Conveyor Jam Detection Using Distance Measurement

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Solution Overview

Problem

Modern parcel processing conveyor systems experience false positive jam signals due to the design of prior photo-optic jam detection systems, which often misinterpret the movement of numerous adjacent articles on wide conveyors as jam conditions.

Innovation Solution

A conveyor jam detection system utilizing a distance detector on one side of the conveyor that measures the distance to parcels and outputs a constant signal for stationary parcels and varying signals for moving parcels, with a controller incrementing a jam count based on constant signals and resetting it for varying signals, to accurately determine jam conditions and reduce false positives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If photo-optic jam detection systems use emitters and detectors on opposite sides of the conveyor to detect jams, then jam detection capability is provided, but false positive jam signals occur due to misinterpretation of moving articles

Engineering Contradiction:
Improvejam detection accuracyVSAvoidfalse positive jam signals
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the detection approach by placing both the emitter and detector on the same side of the conveyor rather than on opposite sides. This configuration change allows the system to measure distance to articles on the conveyor surface, enabling differentiation between moving and stationary articles to eliminate false positives while maintaining jam detection capability.

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If distance measurements are taken at a set location on the conveyor to detect stationary parcels, then jam condition detection is improved, but the system must distinguish between stationary and moving parcels to avoid false positives

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system employs feedback by continuously monitoring distance measurements over time and comparing consecutive readings. When the distance measurement remains constant over a predetermined time period, the system determines a jam condition exists. This temporal feedback mechanism enables accurate distinction between moving and stationary parcels using straightforward signal processing.

Inventive Principle:
Principle #23Feedback

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 system provides a more reliable and accurate detection of jam conditions, reducing false positives and enabling timely corrective action by distinguishing between stationary and moving parcels, thus improving the efficiency of parcel processing.

Implementation Method 1

A detector is located on one side of a conveyor. In a jam condition, the detector measures the distance to a now stationary parcel and outputs a constant distance measurement signal.

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Electromagnetic Induction

Data Source

PatentEP2944591B1Conveyor jam detection system and method
Publication Date: 2017.07.12 SICK INC
  • EP2944591B1 patent drawingFigure 1~4
  • EP2944591B1 patent drawingFigure 5~7
  • EP2944591B1 patent drawingFigure 8

AI summary

A conveyor jam detection system and method includes a distance detector located on one side of a conveyor oriented to detect the distance from the detector to parcels on the conveyor. A controller is responsive to the distance detector and is configured to compare distance measurements, to reset a jam count if different distance measurements over time are greater than a threshold, to increment the jam count if different distance measurements over time are less than the threshold, and output a jam condition signal if the jam count exceeds a set limit.