Slide Fastener Locking Pawl Automatic Engagement

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Solution Overview

Problem

Conventional slide fasteners with locking mechanisms require resilient members like leaf springs, making recycling difficult and prone to wear, and existing solutions either require user intervention for locking or have complex configurations that lead to instability and increased component count.

Innovation Solution

A slide fastener design where the locking pawl is configured to automatically lock by fitting into element rows using the tab's rotation and weight, eliminating the need for resilient members and reducing component count, with specific geometric parameters for optimal locking and ease of assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a leaf spring is used in the locking mechanism, then the locking pawl can be reliably engaged into the element guide passage, but the slider components must be made of different materials (metallic leaf spring and synthetic resin slider), making recycling difficult and time-consuming

Engineering Contradiction:
Improvelocking mechanism reliabilityVSAvoidrecycling ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the leaf spring from the locking mechanism, replacing it with a locking pawl that has an inclined surface capable of self-latching without resilient members. This eliminates the need for metallic components in synthetic resin sliders, enabling all components to be made of the same material for easy recycling.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the design parameters of the locking pawl by incorporating an inclined surface that allows automatic engagement and latching through geometric design rather than elastic force. This parameter change enables the locking function to be achieved without resilient members, solving both reliability and recyclability issues.

Inventive Principle:
Principle #35Parameter changes

2Extent of automation

If a resilient member like a leaf spring is used, then automatic locking can be achieved, but the resilient member is likely to be deteriorated with time passage so that resilience is lost with long term usage

Engineering Contradiction:
Improveautomatic locking capabilityVSAvoidservice life
Core Design Contradiction:
Extent of automationVSDuration of action of stationary object

Solution Approach 1:

The invention replaces the resilient member (leaf spring) with a non-resilient locking pawl that has no elastic components. This eliminates the deterioration issue associated with resilient members over time, as the locking pawl maintains its mechanical properties without elastic fatigue, thereby extending service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes the elastic-mechanical system (leaf spring) with a geometric-mechanical system (locking pawl with inclined surface). This replacement eliminates the time-dependent deterioration of resilient members while maintaining automatic locking capability through pure geometric engagement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If existing solutions without leaf springs are used, then recycling is facilitated, but the slider cannot be automatically locked and requires user intervention to rotate the tab

Engineering Contradiction:
Improverecycling easeVSAvoidautomatic locking capability
Core Design Contradiction:
Ease of manufactureVSExtent of automation

Solution Approach 1:

The invention enables the locking mechanism to be self-actuating through the movement of the slider itself. As the slider moves along the element row, the locking pawl automatically engages and latches without requiring external user intervention to rotate the tab or activate any mechanism, thereby achieving automatic locking.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention creates a dynamic locking mechanism where the locking pawl automatically transitions from a disengaged state to an engaged latched state in response to the slider's movement. The inclined surface of the locking pawl converts the linear motion of the slider into automatic engagement, eliminating the need for manual tab rotation.

Inventive Principle:
Principle #15Dynamics

4Ease of manufacture

If existing solutions without leaf springs are used, then material uniformity is achieved, but the configuration becomes complex with multiple components (slider body, tab, locking pawl, cover body) that need to be assembled

Engineering Contradiction:
Improvematerial uniformityVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention merges the locking pawl with the tab into a single integrated component. This consolidation reduces the total number of parts that need to be assembled and manufactured separately, simplifying the overall structure while maintaining all necessary functions including automatic locking and material uniformity for recycling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated tab-locking pawl component performs multiple functions: it serves as the user-gripping tab, the automatic locking mechanism, and the latching element. This multi-functionality reduces component count and assembly complexity while achieving material uniformity across all slider components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design allows for stable automatic locking without resilient members, reducing wear and maintaining functionality over long periods, while simplifying the slider's structure and assembly, facilitating easier recycling and cost reduction.

Implementation Method 1

the locking pawl is configured to automatically lock by fitting into element rows using the tab's rotation and weight

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP2033534B1Slide fastener
Publication Date: 2018.02.21 YKK CORP
  • EP2033534B1 patent drawingFigure 1
  • EP2033534B1 patent drawingFigure 2
  • EP2033534B1 patent drawingFigure 3~4

AI summary

A slide fastener (1) with a slider locking mechanism without using any resilient member, comprising a slider body (10), a tab (30) attached to the slider body (10) rotatably, and a slider (9) having a locking pawl (31) formed integrally with the tab (30), characterized in that the locking pawl (31) has a pawl portion (37) to be fitted into between the elements (5) and the pawl portion (37) comprises: a first contact surface which, when the tab (30) is rotated after sliding operation of the slider (9) is ended, comes into contact with a first element (5a) of an element row (4) attached to a fastener stringer (2) so as to stop a rotation of the tab (30) temporarily; and a second contact surface which, when the slider (9) starts a forced movement in an element separating direction with the rotation of the tab (30) stopped, makes contact with a second element (5b) so as to stop the forced movement of the slider (9) in a state where the tab (30) restarts to rotate and the pawl portion (37) is fitted into between the elements (5).