Blind Mounting Screw Cage With Elastic Tongues

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Solution Overview

Problem

Existing fixing devices for panels are cumbersome to mount and require specific tools for assembly and disassembly, complicating the process.

Innovation Solution

A U-shaped cage with a circular orifice for receiving a screw head, featuring lateral lugs for rotary movement limitation, axial immobilization tabs, elastic tongues, and a design that allows the screw head to rotate between insertion and locked positions, facilitating easy mounting and dismounting without specialized tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional fixing device with blind mounting capability is used, then the device can be mounted without visible fasteners, but the mounting process becomes cumbersome and requires specific tools

Engineering Contradiction:
Improvemounting easeVSAvoidmounting complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The screw head is nested within the cage structure, with the cage serving as both a mounting mechanism and a protective housing. The screw head fits into a circular orifice in the cage base, allowing the screw to be inserted and locked without external tools, eliminating the need for separate fastening components

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The device enables self-service mounting through the elastic tongues that automatically engage with the screw head when inserted into the cage. The elastic deformation of the tongues provides self-locking functionality without requiring additional tools or complex assembly procedures, making the mounting process intuitive and tool-free

Inventive Principle:
Principle #25Self-service

2Reliability

If a secure locking mechanism is implemented, then the screw is firmly fixed to the support part, but the disassembly process becomes difficult and may damage the support part

Engineering Contradiction:
Improvelocking reliabilityVSAvoiddisassembly ease
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The elastic tongues provide a dynamic locking mechanism that adapts to the screw head during insertion and maintains secure engagement through elastic deformation. This dynamic system allows the screw to be firmly locked during use but can be easily released by applying gentle pressure to overcome the elastic force, enabling tool-free disassembly without damage to the support part

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic tongues change their physical state through elastic deformation, transitioning from a relaxed state during insertion to a compressed state during locking. This parameter change in the elastic tongues allows the mechanism to provide strong holding force during operation while remaining reversible for easy disassembly, maintaining both reliability and ease of repair

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

Enables simple and tool-free mounting and dismounting of the screw and cage assembly, ensuring secure locking and easy removal without damaging the support part.

Implementation Method 1

the retaining means comprise elastic tongues provided on the base of the cage

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the retaining means include the bending of the base of the cage

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the ends of the arms of the cage, by which the latter rests on the front edge of the orifice of the support part form an angle greater than 90° with the axis of the screw, and are elastic, and in that this elasticity of the ends produces a restoring force

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2058531B1Device for attaching a first part to a second part, such as a panel
Publication Date: 2012.09.05 LISI AUTOMOTIVE RAPID
  • EP2058531B1 patent drawingFigure 1A~11B
  • EP2058531B1 patent drawingFigure 2~8

AI summary

The device has a screw (3) blindly mounted on a part e.g. support part (2) via a U shaped cage (6) engaged in a complementary shaped opening (8) in a non-rotating manner. A rectangular shaped head (4) of the screw is received in the cage and movable between insertion and locked positions in the cage. The cage and the screw form an assembly that is locked on the part by rotation of the screw in a position in which the head is behind a rear edge of the opening. The screw is detachably lockable in the cage. The cage with the screw is locked in the part in a removable manner.