Strapping Head Roller Gap Detection for Misfeed Correction

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Solution Overview

Problem

Existing strapping machines face inefficiencies due to misfeeds, where the strapping band does not reach the end of the guide channel, leading to delays and reduced cycle times, as they require manual intervention and wait for the counter-pressure roller to standstill to detect strap absence, which can be contaminated and inaccurately indicate a stop.

Innovation Solution

A strapping head with a pair of rollers and a counter-pressure roller that deflects to indicate strap presence or absence, allowing for immediate correction of misfeeds and improved detection of strap insertion errors, enabling faster retraction and reinsertion of the strapping band without waiting for the counter-pressure roller to stop, thus enhancing cycle efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the counter-pressure roller is used to detect strap absence by waiting for it to standstill, then the detection method is simple, but the cycle time increases and productivity decreases

Engineering Contradiction:
Improvedetection method complexityVSAvoidcycle time
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent replaces the mechanical detection method (waiting for counter-pressure roller to standstill) with an optical sensing system. Optical sensors detect the presence or absence of the strap band in real-time during the roller's rotation, eliminating the need to wait for the roller to stop and significantly reducing cycle time while maintaining detection simplicity through non-contact sensing.

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

Solution Approach 2:

The patent implements real-time feedback through optical sensors that continuously monitor strap presence during the roller's rotation. This immediate feedback allows the system to detect misfeeds and strap absence conditions without waiting for the roller to stop, enabling faster response and reduced cycle time while maintaining simple detection logic through sensor signals.

Inventive Principle:
Principle #23Feedback

2Reliability

If the counter-pressure roller waits to standstill to detect strap absence, then false detection due to contamination is reduced, but time loss increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidwaiting time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces mechanical contact-based detection with optical sensing that detects strap presence through transmission or reflection. This non-contact method eliminates false detections caused by contamination on the roller surface while providing real-time detection during rotation, thus improving reliability without requiring the roller to stop and eliminating time loss.

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

3Measurement precision

If manual intervention is required for misfeed correction, then detection precision can be high, but productivity decreases

Engineering Contradiction:
Improvemisfeed detection precisionVSAvoidarticle turnover
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements automatic misfeed correction through the deflectable counter-pressure roller system. When a misfeed is detected by optical sensors, the roller automatically deflects to guide the strap band back into the correct position, eliminating the need for manual intervention. This self-correcting mechanism maintains high detection precision while significantly improving productivity by enabling continuous automatic operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses optical sensor feedback to automatically trigger the counter-pressure roller's deflection mechanism when misfeeds are detected. This closed-loop control system provides precise detection followed by automatic correction without manual intervention, maintaining high measurement precision while eliminating the productivity loss associated with manual intervention.

Inventive Principle:
Principle #23Feedback

4Productivity

If the strapping band is retracted and reinserted immediately upon error detection, then productivity improves, but the risk of further misfeeds increases

Engineering Contradiction:
Improvecycle efficiencyVSAvoidmisfeed recurrence
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses the deflectable counter-pressure roller as an intermediary element between strap supply and the strapping head. When errors are detected, this intermediary automatically guides and redirects the strap band into the correct position during reinsertion, enabling immediate retry while reducing the risk of further misfeeds through mechanical guidance rather than random reinsertion.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution significantly reduces downtime caused by misfeeds by allowing for immediate detection and correction of strapping band errors, leading to higher cycle times and improved reliability in strapping operations.

Implementation Method 1

the counter-pressure roller is arranged such that it can be deflected transversely to the strapping band guided past the conveyor roller in the direction of the conveyor roller and away from it, wherein a deflection of the counter-pressure roller changes the width of the roller gap

Methodology Applied
Scientific EffectMechanical deflection:

Data Source

PatentEP3034418B1Strapping head and method of handling a strapping band
Publication Date: 2017.08.23 KRONES AG
  • EP3034418B1 patent drawingFigure 1
  • EP3034418B1 patent drawingFigure 2a
  • EP3034418B1 patent drawingFigure 2b

AI summary

A strapping head (01) and a method for handling a strapping band are described. The strapping head (01) is equipped with a strapping guide channel (04) comprising a strapping guide frame (03) arranged or arrangable around a group of articles (18), a strapping conveyor (06), and a tensioning device (07). Viewed in a feed direction (E), the strapping conveyor (06) is arranged after the tensioning device (07) and in front of the strapping guide frame (03). The strapping conveyor (06) comprises at least one pair of rollers (60) formed by a feed roller (61) and a counter-pressure roller (62), between the gap between the rollers of which the strapping band (02) is driven by at least one of the rollers (60) in and against the feed direction (E). The counter-pressure roller (62) is arranged to be deflectable transversely to the strapping band (02) guided past the feed roller (61).A deflection (A) of the counter-pressure roller (62) changes the width of the roller gap. The counter-pressure roller (62) presses against the conveyor roller (61). A first detector (81) is provided at the end of the strapping channel (04), which is triggered as soon as the end (20) of the strapping band (02), which is advancing in an insertion direction (E) into the strapping frame (03), reaches the end of its insertion path located at or near the end of the strapping channel (04). A second detector (82) is provided, which monitors a deflection (A) of the counter-pressure roller (62) towards and away from the conveyor roller (61).The procedure involves monitoring the width of the roller gap to determine whether the strapping band (02) is present or absent. The strapping band (02) is absent if the width of the roller gap has decreased below a predetermined dimension that cannot be undercut if the strapping band (02) is present. In the event of a mis-insertion, where the leading end (20) of the strapping band (02) does not reach the end of the band guide channel (04), the strapping band (02) is retracted as long as it is present in the roller gap. Retraction ceases as soon as no strapping band (02) is present in the roller gap.