Cassette Loading System with Adjustable Conveying Alignment

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Solution Overview

Problem

In the production of liquid crystal display (LCD) devices, the existing systems for loading and unloading cassettes containing precise components like glass motherboards and substrates face challenges in accurately positioning the lift cage due to elongation of steel wire ropes over long distances, leading to difficulties in ensuring smooth conveyance and preventing damage to components.

Innovation Solution

A system comprising a lifting device with multiple conveying devices and position sensors that adjust the height and alignment of the first conveying device within the lift cage to align with secondary conveying devices at different heights, using an auxiliary lifting device and buffer conveying devices to ensure precise positioning and smooth transfer of cassettes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a steel wire rope is used to drive the lift cage for long-distance conveyance between floors, then the lifting device can achieve the required conveyance distance and load capacity, but the steel wire rope elongates over time leading to positioning inaccuracies

Engineering Contradiction:

Improveconveyance distanceVSAvoidstop position accuracy

Core Design Contradiction:

Length of moving objectVSMeasurement precision

Solution Approach 1:

The system employs position sensors to detect the actual position of the lift cage and conveying devices, feeding this information back to the control device. The control device calculates compensation amounts based on the detected initial stop position deviations and elongation amounts, then adjusts the conveying devices accordingly to achieve accurate alignment despite wire rope elongation

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes the position parameters of the conveying devices based on detected elongation. The control device calculates the elongation amount of the steel wire rope and adjusts the position of the first conveying device relative to the lift cage, transforming the fixed positioning problem into a dynamically adjustable parameter

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the lift cage is positioned with high accuracy requirement to ensure smooth cassette transfer, then component damage is prevented, but positioning difficulty increases due to wire rope elongation

Engineering Contradiction:

Improvesmooth transfer reliabilityVSAvoidpositioning difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

Position sensors continuously monitor the positions of the lift cage and conveying devices, providing real-time feedback to the control device. This enables the system to detect positioning deviations caused by wire rope elongation and automatically compensate to maintain reliable cassette transfer

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system replaces pure mechanical positioning with a combination of sensing and control. Instead of relying solely on mechanical precision, the invention uses position sensors and control algorithms to achieve accurate positioning, substituting mechanical rigidity with intelligent control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the first conveying device is fixed relative to the lift cage, then device complexity is reduced, but alignment accuracy with stationary conveying devices deteriorates due to lift cage positioning variations

Engineering Contradiction:

Improveconveying device structureVSAvoidalignment accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The first conveying device is designed to be movable relative to the lift cage rather than fixed. The auxiliary lifting device enables the first conveying device to adjust its height and position dynamically, allowing it to compensate for lift cage positioning variations and maintain accurate alignment with stationary conveying devices on different floors

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system segments the positioning function into two independent parts: the lift cage handles vertical conveyance between floors, while the first conveying device handles horizontal positioning and alignment. This segmentation allows each component to be optimized independently, with the first conveying device capable of fine position adjustments

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9919878B2System for loading and unloading cassette and method for loading and unloading cassette

Publication Date: 2018.03.20 BOE TECHNOLOGY GROUP CO LTD

AI summary

The embodiment of the present disclosure relates to a system and a method for loading and unloading a cassette. The system comprises: a lifting device vertically moving between a first height and a second height; a first conveying device in the lifting device to move the cassette horizontally; a second conveying device to move the cassette in horizontally; a third conveying device to move the cassette horizontally, a plurality of first position sensors to detect a position of the lifting device; and a control device to control vertical movements of the lifting device, and adjust further movements of the first conveying device in the lifting device based on an initial stop position of the lifting device such that the first conveying device is aligned with the second conveying device at the first height, or is aligned with the third conveying device at the second height.