Spring-Loaded Cord Lock Structure to Prevent Button Inclination

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Solution Overview

Problem

Conventional cord locks with reduced cord insertion holes lead to a thin operation member that easily inclines, deteriorating operability, especially when the number of holes is decreased to one.

Innovation Solution

A cord lock design featuring a male member that can move in and out of a female member, with a coil spring urging device and strategically placed straight portions for line contact, along with a partition wall between the cord insertion portions and the coil spring, to enhance operability and prevent the tool from inclining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the number of cord insertion holes is reduced to one, then the device complexity is reduced, but the operation member easily inclines and operability deteriorates

Engineering Contradiction:
Improvenumber of cord insertion holesVSAvoidoperability of operation member
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent introduces straight portions that extend in the cord insertion direction, creating a line contact interface between the male and female members. This dimensional extension from point contact to line contact provides structural support that prevents inclination, allowing single-hole design while maintaining operability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The male member is divided into distinct functional portions: cord insertion portions for cord passage and straight portions for structural support and line contact. This segmentation allows the straight portions to specifically counteract inclination forces while the cord insertion portions maintain minimal configuration for reduced complexity.

Inventive Principle:
Principle #1Segmentation

2Length of moving object

If the male member is pushed in to reduce thickness, then the thickness in pushing direction is reduced, but the operability may deteriorate due to reduced operation area

Engineering Contradiction:
Improvethickness of male memberVSAvoidoperation area of male member
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The male member is designed with dynamic positioning capability, allowing it to move in and out of the female member. The urging device (coil spring) provides automatic positioning that maintains optimal operation area while enabling thickness reduction when pushed in, creating a dynamic balance between these two requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The male member can be nested within the female member when pushed in, reducing the overall thickness of the assembled cord lock. The straight portions and line contact design ensure that even in this nested state, the operational characteristics are maintained through the geometric relationship between the components.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 improves the operability of the male member regardless of the pressing position, prevents the tool from falling, and enlarges the operation area, reducing discomfort and thickness, while maintaining effective cord management.

Implementation Method 1

An urging device (for example, a coil spring) is provided between the female member and the male member, and provides an urging force in a direction wherein the male member protrudes from the opening of the female member.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3254580B1Cord fastener
Publication Date: 2022.09.28 NIFCO INC
  • EP3254580B1 patent drawingFigure 1
  • EP3254580B1 patent drawingFigure 2
  • EP3254580B1 patent drawingFigure 3

AI summary

A cord lock includes a female member including first cord insertion portions through which a cord can be inserted to pass, and has a cylindrical shape including an opening at least at one end; a male member supported to be capable of moving in and out from the opening of the female member to communicate with the first cord insertion portion, and including second cord insertion portions through which the cord inserted to pass through the first cord insertion portions can be inserted to pass; and an urging device (for example, a coil spring) provided between the female member and the male member to provide an urging force in a direction wherein the male member protrudes from the opening of the female member. The second cord insertion portion of the male member and the urging device (for example, the coil spring) are located adjacent to each other, and on opposed faces of the female member and the male member along an insertion direction of the cord inserted to pass through the first cord insertion portion of the female member, straight portions which can carry out at least a line contact are provided.