Clip With Inclined Guide Portions For Creep-Resistant Locking

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Solution Overview

Problem

Conventional clips experience a decline in workability due to creep deformation of leg portions in a diameter-expansion state, leading to difficulties in insertion and increased risk of catching burrs, which affects their reuse and insertion properties.

Innovation Solution

The clip design includes leg-side convex portions and guide portions that incline inwardly, along with a shaft member featuring a shaft-side convex portion and concave portion to facilitate diameter expansion and return to the original condition, ensuring stable insertion and operation even with creep deformation, and incorporates elastic pieces for secure locking and easy unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the leg portions are expanded to the maximum diameter for secure locking, then the locking reliability is improved, but the insertion workability deteriorates due to creep deformation

Engineering Contradiction:
Improvelocking reliabilityVSAvoidinsertion workability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the geometric parameters of the leg portions by providing inclination portions that slope inward from the tip side. This parameter change allows the leg portions to maintain a smaller effective insertion diameter while still achieving full expansion for locking, thereby resolving the contradiction between locking reliability and insertion workability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The inclination portions are designed to guide the leg portions into the attachment hole during insertion before expansion occurs. This preliminary guiding action ensures proper alignment and facilitates easy insertion, while the subsequent expansion phase achieves secure locking without being hindered by creep deformation

Inventive Principle:
Principle #10Preliminary action

2Strength

If the leg portions remain in the diameter-expanded state for a long time, then the locking strength is maintained, but creep deformation occurs leading to loss of insertion properties

Engineering Contradiction:
Improvelocking strengthVSAvoidinsertion precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

By changing the geometric parameters through the inclination portions, the patent creates a structure where the leg portions can expand fully for locking but will not suffer from creep-induced insertion failures, as the inclination design compensates for dimensional changes over time

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The inclination portions are designed in advance to counteract the effects of creep deformation. The inward slope creates a self-correcting mechanism that prevents accumulation of deformation errors, thereby maintaining insertion precision even after prolonged periods in the expanded state

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of operation

If the convex-portion wall faces are designed for smooth sliding, then the ease of operation is improved, but the structural strength is reduced

Engineering Contradiction:
Improvesliding smoothnessVSAvoidstructural strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by providing inclination portions only at specific locations (the tip sides of the leg portions) rather than throughout the entire structure. This localized inclination maintains sliding smoothness where needed while preserving structural strength in the main body of the leg portions

Inventive Principle:
Principle #3Local quality

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 clip maintains excellent workability and insertion properties during reuse, even with creep deformation, and is less affected by burrs or other attachment hole irregularities, enhancing operational reliability and ease of use.

Implementation Method 1

elastic pieces for secure locking and easy unlocking

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3048314B1clip
Publication Date: 2019.12.11 NIFCO INC
  • EP3048314B1 patent drawingFigure 1(a)~1(b)
  • EP3048314B1 patent drawingFigure 2(a)~2(d)
  • EP3048314B1 patent drawingFigure 3(a)~3(c)

AI summary

A clip includes a grommet provided with a projecting portion and a plurality of leg portions, and a shaft member provided with a head portion and a shaft portion, and is switchable between a lock position where the shaft member is pushed into the grommet to expand a diameter of the leg portions, and an unlock position where the shaft member is pushed further into the grommet so as to return the leg portions to an original condition. In main portions, the leg portion includes a leg-side convex portion provided on an inside; a convex-portion wall face inclining in a leg-portion inward direction from a leg-portion tip side; and a guide portion extending to the leg-portion tip side from a leg-side-convex-portion forming portion in a state of being provided together with the leg-side convex portion, and inclining an extending tip side to the inside of the leg portion. The shaft portion includes a shaft-side convex portion engaging the leg-side convex portion to expand the diameter of the leg portion; a concave portion engaging the leg-side convex portion so as to return the leg portion to the original condition from a diameter expansion; an abutment portion abutting against the convex-portion wall face; and a release portion relative to the guide portion.