Vehicle Buckle Assembly Retainer Mechanism

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Solution Overview

Problem

Existing buckle assemblies for motor vehicle seat belts face challenges during assembly due to the positioning of the buckle under the influence of a torsion spring, making it difficult to access the mounting aperture and fastener, which complicates the installation process and can result in additional components being left behind.

Innovation Solution

A retainer mechanism using a polymeric plastic bushing with a frangible connection between the mounting bracket and buckle strap, allowing the buckle to be maintained in a mounting position during assembly and easily released to operate under the influence of a torsion spring, or a second embodiment where the torsion spring interacts with the mounting bracket to maintain the buckle in a position for convenient access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the buckle is mounted under the influence of a torsion spring to enable normal operation, then the buckle can pivot freely within its range of motion, but the mounting aperture and fastener become inaccessible during assembly

Engineering Contradiction:
Improvebuckle pivoting motionVSAvoidmounting access
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The buckle is pre-positioned in a retracted state by the torsion spring before mounting. The retainer mechanism holds the buckle in this preliminary position during assembly, allowing access to mounting features. After mounting, the retainer is released and the buckle is actuated to its operational position, achieving both mounting accessibility and operational freedom.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the buckle is held in a fixed mounting position during assembly, then mounting features are accessible, but the buckle cannot operate in its normal range of motion

Engineering Contradiction:
Improvemounting accessVSAvoidbuckle pivoting motion
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The system is divided into two functional segments: a mounting phase where the retainer mechanism constrains the buckle to a fixed position for accessibility, and an operational phase where the retainer is removed or disengaged, allowing the buckle to pivot freely under torsion spring influence within its normal range of motion.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If additional retainer components are added to maintain mounting position, then assembly is simplified, but the device complexity increases and potential sources of problems are added

Engineering Contradiction:
Improveassembly processVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The retainer mechanism is designed as a temporary, disposable component that serves its purpose during assembly and is then removed or discarded. This approach simplifies assembly by providing easy positioning without requiring permanent retention mechanisms, and the frangible nature ensures no complex disassembly is needed afterward.

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

Solution Approach 2:

The retainer mechanism is intentionally designed to be discarded after serving its mounting function. The frangible connection breaks during normal operation, and the retainer remains in the vehicle as a harmless fragment rather than requiring recovery or removal, simplifying the overall system while maintaining assembly ease.

Inventive Principle:
Principle #34Discarding and recovering

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 convenient access for mounting features while allowing the buckle to pivot within its normal range of motion, eliminating the need for additional components and reducing assembly complexity, and ensuring the buckle operates smoothly after installation.

Implementation Method 1

under the influence of a torsion spring

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 2

the frangible connection is easily broken by forcing the buckle toward its normal range of positions

Methodology Applied
Scientific EffectFracture: Fracture Mechanics

Data Source

PatentEP1719671B1Buckle assembly
Publication Date: 2010.06.30 AUTOLIV ASP INC
  • EP1719671B1 patent drawingFigure 1~2
  • EP1719671B1 patent drawingFigure 3~5
  • EP1719671B1 patent drawingFigure 6~8

AI summary

A buckle assembly (10) for a motor vehicle belt restraint system. The buckle assembly (10) includes a mounting plate (30) and a buckle strap (32) carrying the buckle (24) which is rotatably affixed to the mounting plate (30). A torsion spring (50) acts on the buckle strap (32) to rotationally bias it toward a desired position. The buckle assembly (10) includes a retainer (56) for maintaining the buckle strap (32) in a mounting position, allowing convenient mounting of the device to the motor vehicle structure. Following mounting, the retainer (56) is released to enable the buckle strap (32) to move to its normal range of positions, allowing the buckle assembly (10) to operate in its normal manner.