Stretching Device Linear Drive Asymmetry

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Solution Overview

Problem

Current stretch-blow molding technologies face mechanical and electromagnetic stresses due to the configuration of linear motorization, leading to increased weight, maintenance issues, and reduced precision in manufacturing plastic containers, as well as clogging of position detection systems.

Innovation Solution

The stretching device features centrally mounted coils on the console and magnet channels on the support, eliminating side branches and simplifying wiring and maintenance, with a winding block that integrates coils and an encoder for reduced stress and improved assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the console has lateral arms to receive coils and the slide has magnet tracks on outer walls, then the linear motorization can be implemented, but the device weight increases and mechanical stresses increase requiring reinforced structures

Engineering Contradiction:
Improvelinear motorization implementationVSAvoiddevice weight
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent inverts the traditional symmetric configuration by placing magnet tracks on the inner walls of the slide's lateral arms rather than outer walls, and positioning coils on the console's lateral arms to face inward. This asymmetric arrangement allows the magnet tracks to be integral with the slide structure, eliminating the need for separate mounting and reducing overall device weight while maintaining linear motorization functionality.

Inventive Principle:
Principle #4Asymmetry

2Stability of the object's composition

If the console arms are reinforced to compensate for vibrations from coil resonance, then vibration stability improves, but the device weight and manufacturing complexity increase

Engineering Contradiction:
Improvevibration stabilityVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts the source of vibration problems by repositioning the coils and magnet tracks to face each other through the space between console and slide, rather than having them on opposite outer surfaces. This configuration reduces electromagnetic interference and coil resonance vibrations, eliminating the need for reinforced console arms and associated vibration compensation structures.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the slide is positioned between magnet tracks and coils with lateral adjustment during fixing, then positioning precision can be achieved, but the assembly process becomes tedious and time-consuming

Engineering Contradiction:
Improvelateral positioning precisionVSAvoidassembly time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements preliminary action by making the magnet tracks integral with the slide's lateral arms during manufacturing, rather than requiring separate mounting and adjustment during assembly. This pre-integrated configuration ensures precise lateral positioning is achieved automatically when the slide is assembled to the console, eliminating time-consuming empirical adjustment procedures.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If the encoder is positioned on the console opposite the slide's magnet track for position detection, then position monitoring is achieved, but the encoder becomes fouled by grease deposits requiring regular maintenance

Engineering Contradiction:
Improveposition detection accuracyVSAvoidencoder maintenance
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The patent extracts the encoder from its vulnerable position on the console and relocates it to the winding block, which is positioned away from grease-prone areas. This repositioning maintains the encoder's ability to detect magnet track position through the support structure while protecting it from contamination by grease deposits that would otherwise require regular cleaning and maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

5Extent of automation

If wiring harnesses are installed for coils and encoders, then the components can be powered and controlled, but the wiring complexity increases and maintenance becomes more difficult

Engineering Contradiction:
Improveelectrical control capabilityVSAvoidwiring complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent merges the encoder with the winding block structure, integrating it into the same assembly that houses the coils. This consolidation allows the encoder and coils to share common wiring pathways and mounting structures, reducing the overall wiring complexity and making electrical connections more manageable while maintaining full automation and control capabilities.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration lightens the device, reduces manufacturing costs, simplifies maintenance, and enhances precision by minimizing mechanical and electromagnetic stresses, while also protecting the encoder from contamination and simplifying its wiring and replacement.

Implementation Method 1

coils receiving the current through an electrical wiring are mounted securely to the console, while the magnets are fixed to the moving slide, this configuration then ensuring the movement of the magnets of the moving slide relative to the coils of the fixed console

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4028236B1Stretching device and winding unit of such a stretching device
Publication Date: 2023.07.12 SIDEL PARTICIPATIONS SAS
  • EP4028236B1 patent drawingFigure 1
  • EP4028236B1 patent drawingFigure 2
  • EP4028236B1 patent drawingFigure 3

AI summary

The present invention concerns a stretching device (1), comprising at least a bracket (2) and a support (4) for a stretching rod (5) mounted so as to be able to move relative to the bracket (2), means for moving the support (4) vertically along the bracket (2), with at least two pairs, each being provided with a reel (7) secured to the bracket (2) and a magnet track (8) secured to the support (4), opposite each other, forming a linear drive system, extending symmetrically to a vertical median plane of the bracket (2), characterised by the fact that the reels (7) are mounted at the centre of the bracket (2) to either side along the vertical median plane; and by the fact that the support (4) has a U-shaped cross-section with two lateral branches (40), to which each magnet track (8) is secured. The invention concerns a winding unit (9) with a linear drive system for the stretching device (1).