Insert Coupling in Shoe Injection Moulding

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Solution Overview

Problem

Existing methods for coupling inserts to shoes face challenges such as compromising waterproofing, inefficiency, and risk of damage during injection moulding, due to variable material and mould conditions, and require precise sealing with glues or stitching.

Innovation Solution

A process and apparatus utilizing injection moulding with a mould and counter mould configuration that includes a receiving element and blocking element to securely position the insert, preventing molten material from covering it and ensuring a waterproof, breathable interface, while allowing for easy substitution of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the insert is fixed during the injection moulding process, then the coupling is obtained in an optimal manner, but the insert can be ruined due to the temperature inside the moulds, by the pressure operated by the same moulds, or by undesired insertion of molten material into the mould area used to accommodate the insert

Engineering Contradiction:

Improvecoupling qualityVSAvoidinsert integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The insert is divided into two functional zones: a peripheral coupling zone that contacts the moulds for secure attachment, and a central protected zone that is isolated from mould contact through the creation of a controlled empty chamber. This segmentation allows the insert to be firmly coupled while protecting its functional portions from damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A blocking element is introduced as an intermediary component between the counter mould and the insert. This blocking element creates and maintains an empty chamber that prevents direct contact between the mould and the insert's central portion, thereby protecting the insert from pressure and temperature damage while still allowing the peripheral coupling to occur.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If stitching is used to attach the insert to the upper, then the insert can be attached, but waterproofing is compromised and the process is wasteful in terms of time

Engineering Contradiction:

Improveattachment capabilityVSAvoidwaterproofing

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The attachment of the insert and the waterproofing function are merged into a single injection moulding operation. The plastic material simultaneously bonds the insert to the upper and seals the interface, eliminating the need for separate stitching or gluing operations and ensuring inherent waterproofing.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mechanical stitching system is replaced with an injection moulding process that uses molten plastic material to create both the mechanical bond and the waterproof seal in one operation, improving both efficiency and waterproofing reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If glues or similar substances are used to seal the slots between insert and upper, then waterproofing is improved, but the process becomes more complex and time-consuming

Engineering Contradiction:

ImprovewaterproofingVSAvoidsealing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The injection moulding process itself provides the waterproofing function through the plastic material that fills and seals the interface between the insert and upper. The system uses its own operational material (molten plastic) to achieve sealing, eliminating the need for separate glues or sealing substances and simplifying the overall process.

Inventive Principle:

Principle #25Self-service

4Reliability

If the insert is blocked between mould and counter mould at the peripheral portion, then the pressure exerted is limited to such portion, but the configuration must be precisely designed

Engineering Contradiction:

Improveinsert protectionVSAvoidmould configuration precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The blocking element is pre-configured with a specifically designed geometry that automatically creates the empty chamber and defines the peripheral contact zone. This preliminary design of the blocking element's shape ensures that when it is placed in the counter mould, it automatically achieves the correct positioning and pressure distribution without requiring complex adjustments during the moulding process.

Inventive Principle:

Principle #10Preliminary action

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

Achieves a fast, firm, and waterproof coupling of inserts to shoe uppers with improved breathability and reduced risk of damage, using injection moulding to create a secure and efficient bond without compromising the insert or requiring new moulds.

Implementation Method 1

injecting a plastic material in an interspace formed between a mould and a counter mould

Methodology Applied

Scientific EffectInjection moulding:

Implementation Method 2

injecting a plastic material in an interspace formed between a mould and a counter mould

Methodology Applied

Scientific EffectPhase change (molten to solid): Phase Change

Data Source

PatentEP3358983B1Process and apparatus for coupling an insert to a shoe

Publication Date: 2020.09.23 HAWAI ITAL

Figure 1~4

AI summary

This is a process and an apparatus for coupling an insert to a shoe optimal way, without using sealing or gluing substances.