Sheet Workpiece Length Measurement Without Conveyor Slip Errors
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Solution Overview
Problem
Existing apparatuses struggle to accurately measure the length of very long, oversized plate-shaped workpieces without measurement errors due to slip between the conveying device and the workpiece, which is exacerbated by braking and acceleration, and require complex synchronization of slide gauges with the conveying device.
Innovation Solution
An apparatus with two measuring devices, each equipped with a driver that can be selectively coupled and decoupled from the workpiece, allowing for continuous measurement by moving in the opposite direction to the conveying direction, using suction grippers and contactless interaction with stationary measuring rulers, synchronized by a control unit to ensure accurate length measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the workpiece is measured continuously during conveyance using a position encoder, then the length measurement can be performed for very long workpieces, but measurement errors occur due to slip between the conveying device and the workpiece during braking and acceleration
Solution Approach 1:
The patent replaces the mechanical position encoder system with an optical measurement system. A measuring device with a ruler and optical sensor (such as a laser scanner or camera) is used to detect the position of the workpiece edges optically, eliminating the mechanical contact and slip issues inherent in encoder-based systems. This substitution of mechanical detection with optical detection resolves the contradiction between extended measurement range and measurement precision.
Solution Approach 2:
The patent introduces an intermediary reference system - a fixed ruler or scale positioned alongside the conveyance path - that serves as a stable reference for measurement. The measuring device reads positions relative to this intermediary reference rather than relying on the moving conveying device's position encoding, thereby eliminating errors caused by slip between the conveying device and workpiece.
2Measurement precision
If slide gauges are used to measure the position of the workpiece, then measurement accuracy can be improved, but the synchronization between slide gauges and the conveying device becomes complex
Solution Approach 1:
The patent extracts the measurement function from the moving conveying system and places it in a stationary measuring device. The ruler and optical sensor are fixed in position, reading the workpiece position relative to a fixed reference frame. This separation eliminates the need for synchronization between moving measurement components and the conveying device, reducing system complexity while maintaining high measurement precision.
Solution Approach 2:
The patent creates a stationary optical copy or representation of the position information through the fixed ruler and optical sensing system. Instead of physically synchronizing moving parts, the system captures position data optically from a fixed reference, eliminating synchronization requirements while preserving measurement accuracy.
3Measurement precision
If the workpiece surface is contacted by measuring devices, then accurate position detection can be achieved, but the workpiece surface may be damaged or contaminated
Solution Approach 1:
The patent replaces mechanical contact measurement with optical measurement. The optical sensor (laser scanner, camera, or other optical detector) measures the workpiece position and edges without physical contact, eliminating the risk of surface damage or contamination while maintaining measurement precision. The optical field interacts with the workpiece surface without exerting mechanical force.
Solution Approach 2:
The patent introduces light as an intermediary between the measuring device and the workpiece surface. The optical measurement system uses light reflection or transmission to detect workpiece position and dimensions without direct mechanical contact, thereby preventing surface damage or contamination while achieving accurate measurement.
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 accurate, continuous measurement of long workpieces without interruptions, minimizing slip-related errors and avoiding surface damage, while allowing for easy cleaning and protection of the workpiece surfaces.
Implementation Method 1
suction grippers
Data Source
AI summary
An apparatus for measuring a plate-shaped workpiece comprises a conveying device for conveying the plate-shaped workpiece in a conveying direction along a conveying path and first and second measuring devices including respective first and second drivers and respective first and second measuring rulers. Each of the first and second drivers is selectively couplable to and decouplable from a main surface of the plate-shaped workpiece. In a coupled state, the drivers are moveable together with the plate-shaped workpiece in the conveying direction and, in a decoupled state, are actively movable in a direction opposite to the conveying direction. The measuring rulers extend in the conveying direction such that the positions and/or movement distances of the drivers in the conveying direction are detectable. The first and second measuring rulers detect different regions of the conveying path of the plate-shaped workpiece in the conveying direction.