Scoring Bridge Carriage Positioning and Force Control

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Solution Overview

Problem

Current on-line and off-line scoring bridges face challenges in accurately positioning carriages to reduce spacing errors between scoring wheels, leading to tolerance issues in score line spacing, and they often require complex mechanisms to maintain a constant scoring force, which increases costs and complexity.

Innovation Solution

A system with first and second drive arrangements for moving carriages along reciprocating paths, position measuring devices for generating position signals, and a motion detector to determine offsets, allowing for precise positioning of carriages and maintaining a constant load on scoring wheels using a servomotor and biasing mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If automatic positioning systems are used to space carriages, then positioning speed is improved, but positioning precision deteriorates (tolerance ±0.025 inch not met)

Engineering Contradiction:
Improvepositioning speedVSAvoidspacing precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical positioning systems with a computer-controlled system that uses sensors to detect carriage positions and calculates offset values. The system determines the actual position of each carriage relative to its commanded position and applies correction offsets to achieve precise spacing tolerances of ±0.025 inch or better, overcoming the limitations of pure mechanical positioning.

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

2Manufacturing precision

If complex mechanisms are used to maintain constant scoring force, then scoring uniformity is improved, but device complexity increases

Engineering Contradiction:
Improvescoring uniformityVSAvoidmechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs feedback control where sensors detect the actual position of scoring wheels and the system calculates offset values to maintain constant scoring force. This feedback mechanism allows the system to compensate for variations in glass thickness and conveyor alignment without requiring complex mechanical mechanisms, thereby maintaining scoring uniformity while reducing overall system complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts positioning parameters (offset values) based on real-time sensor data to maintain constant scoring force. By changing the positional parameters of carriages rather than relying on complex mechanical force control mechanisms, the system achieves uniform scoring while keeping the device complexity manageable.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If tolerance range between adjacent scores is reduced, then glass sheet quality is improved, but seaming and grinding requirements increase

Engineering Contradiction:
Improvescore spacing toleranceVSAvoidpost-processing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs preliminary positioning actions by calculating and applying offset values to carriage positions before the scoring operation occurs. This preliminary correction ensures that adjacent score lines are spaced within the tight ±0.025 inch tolerance, thereby reducing the need for subsequent seaming and grinding operations and improving overall productivity.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If glass thickness variations and conveyor alignment issues occur, then scoring consistency deteriorates, but surface damage increases

Engineering Contradiction:
Improvescoring consistencyVSAvoidsurface damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses feedback control where sensors detect variations in glass thickness and conveyor alignment, and the system responds by calculating offset values to maintain constant scoring force. This feedback mechanism compensates for disturbances in real-time, maintaining scoring consistency while preventing excessive surface damage that would occur with uncorrected force variations.

Inventive Principle:
Principle #23Feedback

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 achieves accurate spacing of score lines with a tolerance of less than ±0.025 inch, reducing the need for extensive seaming and grinding, and maintains a consistent scoring force despite variations in glass thickness and conveyor alignment, thereby minimizing surface damage and operational costs.

Implementation Method 1

one or more carriages each having a scoring wheel assembly having a load applying arrangement that applies a constant load to a scoring wheel

Methodology Applied
Scientific EffectSpring biasing: Spring

Data Source

PatentEP1893538B1Controlled scoring bridge
Publication Date: 2013.07.17 PPG INDUSTRIES OHIO INC
  • EP1893538B1 patent drawingFigure 1~2
  • EP1893538B1 patent drawingFigure 3
  • EP1893538B1 patent drawingFigure 4

AI summary

A scoring bridge includes a plurality of moveable mounted carriages. The carriages each have a rotor, and the bridge has a linear stator to move the carriages. The position of a carriage designated as a reference carriage is recorded as it moves past a motion detector. The position of each remaining carriages is recorded as they individually move past the detector. The difference between the position of a carriage and the position of the reference carriage is an offset that is added to the position reading of the carriage to accurately space the carriage form the reference carriage. Each of the carriages can have a scoring assembly that includes servomotor acting through a gear arrangement on a scoring wheel. The servomotor applies a constant load to the scoring wheel and adjusts the load for any positive or negative displacement of the scoring wheel from a reference position.