Vacuum Preload Drive Wheels for Flat Panel Conveying
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Solution Overview
Problem
Conventional conveyer systems face challenges in maintaining grip and accurately directing light or flexible flat objects, such as flat panel displays and solar-cell substrates, due to low friction, leading to slipping and misdirection, especially when supported by air-cushion platforms.
Innovation Solution
The implementation of vacuum preload drive-wheels, which enhance the driving force by applying a vacuum holding down force, decoupling the conveying forces from gravity and increasing the coefficient of friction, allowing for accurate linear motion and reduced substrate non-flatness by up to a factor of 10 compared to conventional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheels are used to convey light or flexible flat objects over air-cushion platforms, then the objects can be supported without contact, but the wheels slip due to low friction and fail to advance the objects accurately
Solution Approach 1:
The vacuum preload mechanism applies a holding down force to the wheels before conveying begins, pre-establishing the necessary friction contact between wheels and substrate. This preliminary action ensures that when the substrate is placed on the air-cushion platform, the wheels already have sufficient grip to prevent slipping and enable accurate conveying.
2Force
If conventional wheels are used without vacuum preload, then the system is simpler, but the driving force is insufficient to prevent wheel slip on air-supported substrates
Solution Approach 1:
The invention employs vacuum (a pneumatic principle) to create a preload force on the drive wheels. By applying negative pressure through vacuum ports in the counter plate, the system generates a holding down force that increases friction between the wheels and substrate, thereby enhancing the driving force without requiring mechanical compression or additional complex mechanisms.
3Productivity
If vacuum preload is applied to enhance friction and grip, then conveying performance improves, but the system complexity increases due to additional vacuum components
Solution Approach 1:
The counter plate serves multiple functions: it provides structural support for the wheels, acts as a mounting surface for vacuum ports, and functions as part of the aeromechanical platform structure. By integrating these functions into a single component, the invention reduces overall system complexity while maintaining the vacuum preload capability that enhances conveying performance.
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 enables high-performance conveying with reduced drive wheels, faster acceleration, and cost-effective handling of thin, wide-format substrates, minimizing contact and contamination, and is suitable for non-contact platforms and automation modules in manufacturing lines.
Implementation Method 1
The implementation of vacuum preload drive-wheels, which enhance the driving force by applying a vacuum holding down force
Implementation Method 2
when the objects are primarily supported over an air-cushion (or an AM-platform)
Data Source
AI summary
A system and method for conveying and for accurately handling a generally flat object employing a plurality of support elements. The system comprises: a plurality of vacuum preload drive wheels arranged in one or more drive units, each drive unit comprising at least one vacuum preload drive wheel; one or more vacuum ports located on one or more counter plates adjacent each of the vacuum preload drive wheels, for applying induced holding down forces on the object. The vacuum ports of each drive unit are fluidically connected to a main vacuum pipe with controllable valve to a vacuum source. When the main vacuum pipe is connected to a vacuum source the normal force between the object and the vacuum preload drive wheels is increased and accordingly the lateral drive force is increased.