Tubular Body Locking Structure for Low-Force Insertion and Release

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Solution Overview

Problem

Conventional tubular body connectors require high operating force for locking and unlocking due to frictional resistance caused by the curved wire hitting the slit edge, making operation difficult.

Innovation Solution

The locking mechanism features an oblique sliding surface that widens at the leading end to reduce friction, allowing the locking member to move smoothly in the outer diameter direction and be guided to a locking position, with a run-up portion to ease movement and a holding portion to secure the locking member, utilizing a combination of first, second, and third curved portions for secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the curved portion of the wire passes through the slit in the connector, then locking and unlocking function is achieved, but the curved portion hits the edge of the slit causing frictional resistance that increases operating force

Engineering Contradiction:
ImproveoperabilityVSAvoidoperating force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

A guide unit is introduced as an intermediary component between the locking member and the housing. This guide unit includes an oblique sliding surface that mediates the movement of the locking member, preventing direct contact between the locking member and the slit edge, thereby reducing frictional resistance and operating force

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The oblique sliding surface changes the movement parameter of the locking member by providing a tapered guide path. This parameter change allows the locking member to move smoothly from a widened state to a locked state while reducing the force required for operation

Inventive Principle:
Principle #35Parameter changes

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

This design reduces the operating force required for inserting and releasing tubular bodies by minimizing frictional resistance and improving operability, allowing for easier connection and disconnection with reduced force.

Implementation Method 1

the curved portion of the wire hits an edge of the slit when locking or unlocking the pipe, and slidingly moves while touching the edge, so that an operating force required for locking or unlocking a plug becomes higher because of frictional resistance

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3460308B1Locking mechanism for tubular body
Publication Date: 2022.01.26 NIFCO INC
  • EP3460308B1 patent drawingFigure 1
  • EP3460308B1 patent drawingFigure 2
  • EP3460308B1 patent drawingFigure 3

AI summary

A locking member is mounted to the housing to be able to move in the outer diameter direction by a tapered portion of the tubular body, when the tubular body is inserted. The housing is equipped with slits formed to pass a curved portion bent in the inner diameter direction disposed at a leading-end side of the locking member and to lock with the engagement portion of the tubular body mounted on the housing. A gap is disposed between the curved portion, and the end portion of the slit positioned at a side in an opposite direction to the leading-end side of the locking member, so that there is no contact while at least the locking member is moving.