Moulding Unit Compensation Gripper for Thermoplastic Container Production

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Solution Overview

Problem

Existing molding units for thermoplastic containers face issues with mechanical deformations and quality defects due to play between molding elements caused by high pressures during blow molding, which are not adequately addressed by compensation chambers, leading to increased costs and energy consumption.

Innovation Solution

A molding unit with a compensation clamp that directly acts on mold carriers to eliminate play between molding elements, providing a consistent and adjustable compensation force that exceeds the forces exerted by pressurized air, ensuring the molding elements remain contiguous during container formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compensation chamber is used to counteract forces during blow molding, then molding elements remain pressed together, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvemolding element contactVSAvoidcompensation chamber structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the compensation function from a separate compensation chamber and integrates it directly into the mold carrier structure. The mold carrier itself becomes the compensation element, eliminating the need for an additional compensation chamber while maintaining the ability to counteract blow molding forces and keep molding elements pressed together.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the compensation function with the mold carrier structure. The mold carrier is designed to be movable relative to the mold, allowing it to automatically compensate for forces during blow molding by adjusting its position, thereby combining two functions (holding and compensating) into a single component.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If a compensation chamber is used to maintain molding element contact, then quality improves, but energy consumption increases

Engineering Contradiction:
Improvecontainer qualityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The mold carrier performs compensation automatically through its own movability relative to the mold. The system uses the blow molding forces themselves to drive the mold carrier movement, which in turn maintains molding element contact. This self-service mechanism eliminates the need for additional energy-consuming compensation systems while maintaining container quality.

Inventive Principle:
Principle #25Self-service

3Reliability

If locking means are used to hold mold carriers in closed position, then molding elements stay together, but operating clearance causes play between elements

Engineering Contradiction:
Improvemold carrier positioningVSAvoidmolding element contact
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention transitions from a static locking mechanism to a dynamic compensation system. The mold carrier is designed to be movable relative to the mold, allowing it to adapt its position dynamically during blow molding to maintain molding element contact, thereby eliminating the play problem caused by fixed locking means operating clearance.

Inventive Principle:
Principle #15Dynamics

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 compensation clamp simplifies design and assembly, reduces energy consumption, and enhances manufacturing rates by eliminating the need for complex locking mechanisms, resulting in improved container quality and reduced production costs.

Implementation Method 1

compensation means selectively controlled to exert a compensation force, tending to press the molding elements against each other at the level of the joint plane and to oppose the forces that the pressurized fluid exerts on the molding elements

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

pressurized fluid exerts on the molding elements during the molding of a container from a preform

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP3057767B1Moulding unit for the manufacture of containers comprising a compensation gripper
Publication Date: 2017.08.30 SIDEL PARTICIPATIONS SAS
  • EP3057767B1 patent drawingFigure 1
  • EP3057767B1 patent drawingFigure 2
  • EP3057767B1 patent drawingFigure 3

AI summary

The present invention relates to a moulding unit (10) for the manufacture of containers from preforms made of thermoplastic, said moulding unit (10) being characterized in that it comprises compensating means which are formed of at least one gripper (60) which acts on mould carriers (16) that carry the mould (12) of the unit (10) in order to clamp them against one another when the moulding unit (10) is in the closed position and to apply a compensating force that tends to clamp together moulding elements (14) of the mould (12) at said parting line (P) and opposes the forces that a pressurised fluid applies to the moulding elements (14) when a container is being moulded from a preform.