Waterproof Slide Fastener Injection Mold Design

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Solution Overview

Problem

Conventional slide fasteners lack comprehensive waterproofing, particularly at the central gap and slits between coupling elements, leading to inadequate water resistance when subjected to transverse forces, resulting in reduced durability and smooth operation.

Innovation Solution

A thermal plastic elastomer injection mold with an arc-shaped ridge and injection port allows the elastomer to be injected into the gap and slits between support-tapes, forming a water-impermeable structure by filling the gap and slits, enhancing the waterproofing and durability of the slide fastener.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal plastic elastomer is injected from the exterior of coupling elements to cover outer surfaces, then waterproof function is improved, but friction between elastomer and slider increases and service life is shortened

Engineering Contradiction:

Improvewaterproof functionVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

Instead of injecting elastomer from the exterior of coupling elements as in prior art, this invention inverts the injection approach by injecting from the interior gap between support tapes outward through the slits. The injection port is formed on the inner surface of the gap, allowing elastomer to flow from inside out, which prevents direct contact between elastomer and slider while still achieving waterproofing.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If thermal plastic elastomer is injected to cover outer surfaces of coupling elements, then waterproof function is improved, but the slide fastener becomes heavy and inflexible

Engineering Contradiction:

Improvewaterproof functionVSAvoidweight and flexibility

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

This invention applies elastomer locally only where needed for waterproofing - specifically filling the slits between coupling elements and the gap between support tapes - rather than coating the entire exterior surface. This localized application maintains the light weight and flexibility of the slide fastener while providing comprehensive waterproof protection at critical locations.

Inventive Principle:

Principle #3Local quality

3Reliability

If thermal plastic elastomer is injected from exterior to cover coupling elements, then waterproof function is improved, but opening and closing operation becomes unsmooth

Engineering Contradiction:

Improvewaterproof functionVSAvoidopening and closing operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

By inverting the injection direction to flow from interior to exterior, the elastomer fills the slits and gap without forming a thick exterior layer that would interfere with slider movement. The slider moves along the support tapes rather than directly contacting the elastomer, ensuring smooth operation while maintaining waterproof integrity.

Inventive Principle:

Principle #13The other way round (Inversion)

4Ease of manufacture

If conventional materials are used for slide fastener, then ease of manufacture is maintained, but comprehensive waterproof function cannot be provided

Engineering Contradiction:

Improveease of manufactureVSAvoidcomprehensive waterproof function

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

This invention combines conventional slide fastener components (support tapes, coupling elements, slider) with thermal plastic elastomer to create a composite structure. The elastomer is injected to fill and seal the slits and gap, creating a composite waterproof assembly that maintains ease of manufacture using existing components while achieving comprehensive waterproof function through the added elastomer layer.

Inventive Principle:

Principle #40Composite materials

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 provides a water-impermeable slide fastener with improved durability and flexibility, suitable for use in garments and portable devices, maintaining the softness and ease of use while ensuring a comprehensive waterproof function.

Implementation Method 1

a thermal plastic elastomer, extruded out from the at least one extruder and passing the thermal plastic elastomer injection port so as to be injected into the gap and into slits inside two rows of coupling elements

Methodology Applied

Scientific EffectExtrusion: Extrusion

Implementation Method 2

the thermal plastic elastomer to be injected into the gap and into slits inside two rows of coupling elements disposed at inner edges of the pair of support-tapes, wherein the slide fastener is formed with a water impervious structure

Methodology Applied

Scientific EffectSealing:

Data Source

PatentUS10800081B2Thermal plastic elastomer injection mold, water impervious slide fastener manufactured utilizing the same and finished product having the water impervious slide fastener

Publication Date: 2020.10.13 CHOU CHAO MU

AI summary

A thermal plastic elastomer injection mold comprises: a mold base, formed with a platform having a top surface thereof formed with an arc-shaped surface adhered with a pair of support-tapes of a slide fastener and formed with an elongated arc-shaped ridge having a wedge-shaped tip thereby being able to be stably moved into a gap between the pair of support-tapes and a surface of the arc-shaped ridge is formed with a thermal plastic elastomer injection port connected to at least one extruder; and a thermal plastic elastomer, extruded out from the at least one extruder and passing the thermal plastic elastomer injection port so as to be injected into the gap and slits inside two rows of coupling elements disposed at inner edges of the pair of support-tapes, wherein the slide fastener is formed with a water impervious structure after the thermal plastic elastomer inside the gap is cut.