Rivet Sorting Machine Using Optical Measurement

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Solution Overview

Problem

Current machines for measuring and sorting rivets with countersunk heads face challenges in meeting precise aerodynamic and aesthetic requirements due to strict out-of-flush constraints, which are difficult to achieve with existing standards and manual drilling methods, leading to time-consuming processes and high rejection rates.

Innovation Solution

A machine that uses optical image acquisition and processing to measure multiple structural characteristics of rivets, sorting them into precise subclasses based on predetermined ranges, allowing for automatic sorting and exclusion of non-compliant parts, thereby enhancing precision and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual drilling with adaptation to exact dimensions is implemented, then offset precision can be improved, but time consumption increases significantly

Engineering Contradiction:
Improveoffset precisionVSAvoidtime consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by measuring and sorting rivets into precision subclasses before the assembly operation. The sorting device classifies rivets by head diameter into multiple subclasses (e.g., 40A, 40B, 40C) with progressively tighter tolerances, so that when assembly occurs, the correct precision subclass is already selected, eliminating the need for time-consuming on-site measurement and adaptation during drilling operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the manual mechanical measurement and adaptation process with an automated optical sorting system. Instead of operators manually measuring rivet dimensions and selecting appropriate ones during assembly, an optical sorting device with image capture and processing automatically measures rivet head diameters and sorts them into precision subclasses, substituting manual mechanical operations with automated optical-mechanical systems

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

2Manufacturing precision

If existing standards are modified to meet precise offset requirements, then offset precision can be improved, but implementation difficulty increases

Engineering Contradiction:
Improveoffset precisionVSAvoidimplementation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the standard rivet reference class into multiple precision subclasses based on head diameter measurements. Instead of modifying existing standards, the system segments the rivet population into subclasses (e.g., 40A: 6.20-6.40mm, 40B: 6.40-6.60mm, 40C: 6.60-6.78mm) with progressively tighter tolerances, allowing selection of the appropriate subclass for each precision requirement without changing the underlying standard

Inventive Principle:
Principle #1Segmentation

3Productivity

If automated sorting into multiple precision subclasses is implemented, then productivity can be improved, but device complexity increases

Engineering Contradiction:
Improvesorting speedVSAvoidsorting system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies self-service by designing a sorting system where the rivets effectively sort themselves into precision subclasses through automated optical measurement and classification. The system captures images of rivets, processes the images to measure head diameters, and automatically directs rivets into appropriate precision bins based on measured dimensions, eliminating the need for manual intervention while achieving high-speed sorting into multiple precision categories

Inventive Principle:
Principle #25Self-service

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

The machine enables rapid and precise measurement and sorting of rivets, achieving a rate of around 3 parts per second, with the ability to refine reference classes into multiple subclasses, significantly reducing the time and effort required to meet stringent technical specifications.

Implementation Method 1

optical means for acquiring images of each part to be sorted conveyed by said conveying device

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3390962B1Machine for measuring and sorting countersunk-head rivets-type assembly parts
Publication Date: 2019.11.13 STELIA AEROSPACE
  • EP3390962B1 patent drawingFigure 1~2
  • EP3390962B1 patent drawingFigure 3~4j

AI summary

The invention relates to a machine for measuring and sorting rivets (9) comprising: a vessel (5) for feeding rivets (9) to be sorted, a plurality of trays (11, 21, 31) for receiving sorted rivets, a device for conveying (6, 7) rivets to be sorted, optical means (13, 14, 23, 24, 33, 34, 50) for acquiring images of each rivet (9) to be sorted, a unit (8) for processing images configured to provide at least one measurement of at least one structural feature of each rivet to be sorted, means (15, 25, 35) for distributing each rivet towards a receiving tray, selected as a function of at least one measurement of at least one structural feature of said part supplied by said processing unit (8), each receiving tray being associated with a predetermined range of values of at least one structural feature for sorting the rivets.