Adhesive Chime with Mechanical Locating Feature

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Solution Overview

Problem

Plastic kegs with hot melt adhesive attachment can tilt under certain conditions, causing the dip tube to become dislodged and leaving a residual volume of liquid due to the adhesive softening at elevated temperatures or during rough handling.

Innovation Solution

A container assembly with a central projection on the bottom wall and an inner hub with a central opening or slots on the chime, which allows for adhesive fixation while preventing lateral movement, ensuring the keg remains upright and allowing for greater liquid withdrawal with minimal residual volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If hot melt adhesive is used to fix the chime to the container, then the attachment is quick and inexpensive with distributed attachment points, but the adhesive softens at elevated temperatures causing the container to tilt and leaving residual liquid volume

Engineering Contradiction:
Improveattachment speed and costVSAvoidstability under elevated temperature conditions
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention divides the attachment system into two independent functional components: (1) hot melt adhesive for quick and inexpensive fixation of the chime to the container, and (2) a mechanical locating feature (protrusion recess combination) that prevents tilting by constraining lateral movement. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges two different fixation mechanisms - chemical bonding (adhesive) and mechanical constraint (protrusion-recess interface) - into a single hybrid attachment system. The adhesive provides initial bonding and distributed attachment, while the mechanical features provide positional stability and prevent tilting under thermal conditions.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the container tilts within the bottom chime, then the dip tube becomes dislodged from the lowest part of the container, but this results in residual liquid remaining in the keg

Engineering Contradiction:
Improvedip tube positioningVSAvoidresidual liquid volume
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The mechanical locating feature (protrusion and recess) acts in advance to prevent the container from tilting within the chime. By constraining lateral movement before any tilting can occur, the system ensures the dip tube remains properly positioned at the lowest part of the container, thereby preventing residual liquid accumulation.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The protrusion-recess combination establishes the correct vertical orientation of the container relative to the chime during assembly, before the keg is filled and subjected to thermal conditions. This preliminary positioning ensures that under normal operation, the dip tube will always reach the lowest point of the container.

Inventive Principle:
Principle #10Preliminary action

3Strength

If the central opening of the inner hub receives the central projection, then lateral movement is prevented without fixation, but this requires precise profile matching between the opening and projection

Engineering Contradiction:
Improvelateral movement resistanceVSAvoidprofile matching accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The central projection of the container bottom is nested within the central opening of the chime's inner hub, creating a tapered interference fit. This nested arrangement provides lateral constraint through friction and geometric interference, preventing tilting without requiring additional fixation elements or excessive manufacturing precision.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The protrusion and recess are designed with specific dimensional parameters (diameter, depth, taper angle) that create an optimal balance between lateral constraint and manufacturing feasibility. By carefully selecting these parameters, the system achieves sufficient lateral stability while accommodating normal manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

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 solution maintains the advantages of adhesive fixation while ensuring the keg remains stable and upright under various conditions, enabling a larger volume of liquid to be withdrawn with a smaller residual volume.

Implementation Method 1

a bottom chime fixed to a bottom end of the container using a hot melt adhesive as the primary means of attachment

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3494057B1Containers with adhesively attached chimes
Publication Date: 2020.11.04 POLYKEG SRL
  • EP3494057B1 patent drawingFigure 1
  • EP3494057B1 patent drawingFigure 2
  • EP3494057B1 patent drawingFigure 3

AI summary

A keg includes a container 1 and a chime 3 fixed to each other by means of an adhesive. The container has a peripheral side wall 4, and a top wall formed with a central neck containing a valve fitting provided with a dip tube which extends into the container. A bottom wall 9 is formed with a central projection 10 defining an internal well inside the container which receives the lower end of the dip tube. The chime 3 has an inner hub 12 with a central opening 13, legs 14 which extend outwardly from the inner hub, and an outer skirt 15 joined to outer ends of the legs 14. The central opening 13 of the inner hub 12 receives the central projection 10, without fixation, to locate the inner hub against lateral movement. The central opening 13 may have the same internal profile as the outer profile of the central projection 10. In a modification the central opening 13 incorporates a plurality of slots which radiate outwardly to define a plurality of flexible inwardly-directed fingers which locate the inner hub and accommodate variations in the relative axial position of the central projection 10 and the inner hub 12.