Sheet Workpiece Pickup Detection at the Lift Upper Limit

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Solution Overview

Problem

Existing workpiece conveying systems face challenges in detecting the quantity and posture of sheet-like workpieces accurately and reliably, especially under conditions of vibrations during the raising operation, which hinders high-speed conveyance.

Innovation Solution

A workpiece conveying system equipped with a magnetic or vacuum suction workpiece stopper that reduces vibrations at the upper limit position, allowing for efficient detection of the number and posture of workpieces using a conveyed workpiece number detector and posture detector, which continue or correct the conveyance operation based on detection results without reducing the conveying speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the workpiece conveying operation is stopped to detect taking of two workpieces, then the detection accuracy is improved, but the conveying speed is reduced

Engineering Contradiction:
Improvedetection accuracyVSAvoidconveying speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by detecting the number of workpieces at the upper limit position before the conveying operation continues. The detection is performed at a predetermined position where the workpiece temporarily stops during the raising operation, allowing detection to be completed before the workpiece is conveyed to the next step, thus maintaining high-speed conveying without stopping the overall operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuity of useful action by integrating the detection process into the existing conveying operation. The workpiece is detected at the upper limit position during the normal raising cycle, and the detection result is used to control subsequent conveying. This allows the conveying operation to continue without interruption while still achieving accurate detection of the number of workpieces.

Inventive Principle:
Principle #20Continuity of useful action

2Productivity

If the workpiece is raised quickly to maintain high-speed conveyance, then the conveying speed is improved, but vibrations are generated that hinder accurate detection

Engineering Contradiction:
Improveconveying speedVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary anti-action by using the workpiece stopper to counteract vibrations at the upper limit position. The stopper temporarily holds the workpiece, preventing vibration-induced detection errors. This allows accurate detection to be performed even though the workpiece was raised quickly, thus maintaining both high conveying speed and detection accuracy.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The workpiece stopper functions as a cushioning mechanism by providing a temporary stopping point at the upper limit position. This predetermined stopping position allows the system to absorb and dampen vibrations before detection occurs, ensuring accurate detection results even when the workpiece has been raised at high speed.

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

3Device complexity

If a simple detection method is used, then the device complexity is reduced, but the reliability of detection is worsened

Engineering Contradiction:
Improvedetection system complexityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a workpiece stopper as an intermediary element that facilitates reliable detection. The stopper creates a controlled stopping condition at the upper limit position, which serves as a mediator between the high-speed conveying operation and the detection process. This simple mechanical intermediary ensures reliable detection without requiring complex detection systems or multiple sensors.

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

Enables fast and reliable detection of workpiece quantity and posture, preventing issues associated with conveying multiple or misaligned workpieces, thus ensuring high-speed and accurate conveyance to the next processing step.

Implementation Method 1

a workpiece holding unit (114) supported on a distal end of the second arm (113) and configured to hold and release the workpiece (W)

Methodology Applied
Scientific EffectMagnetic suction: Magnetism

Implementation Method 2

a workpiece holding unit (114) supported on a distal end of the second arm (113) and configured to hold and release the workpiece (W)

Methodology Applied
Scientific EffectVacuum suction: Suction

Implementation Method 3

a magnetic or vacuum suction workpiece stopper (121) configured to be brought into abutment against a top surface of the workpiece (W) held and raised by the workpiece holding unit (114) at an upper limit position of raising the workpiece (W)

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP3685934B1Workpiece conveying system, conveyed workpiece number detector, and control method for the workpiece conveying system
Publication Date: 2024.02.21 AIDA ENGINEERING LTD
  • EP3685934B1 patent drawingFigure 1
  • EP3685934B1 patent drawingFigure 2
  • EP3685934B1 patent drawingFigure 3

AI summary

Provided is a workpiece conveying system 100 configured to convey a sheet-like workpiece to a downstream step, including: a workpiece conveyor 110 configured to lift through attraction holding, by a workpiece holding unit 114, an uppermost workpiece W of a stack 102 , and convey the uppermost workpiece W of the stack 102 to the downstream step one by one; and a conveyed workpiece number detector 122 configured to detect the number of workpieces W held by the workpiece holding unit 114 at a detection timing, at which the workpiece W held and raised by the workpiece holding unit 114 in accordance with a normal workpiece conveying operation performed by the workpiece conveyor 110 reaches an upper limit position of raising the workpiece W, and at which a moving speed component of the workpiece W in a raising direction is 0.